Recursos de colección

UTL Repository Universidade Técnica de Lisboa (35.475 recursos)

O Repositório Institucional da Universidade Técnica de Lisboa desenvolvido no âmbito do projecto RCAAP. Este repositório destina-se a recolher, preservar e disponibilizar o acesso às publicações científicas e didácticas de seis: Escolas da UTL: Faculdade de Medicina Veterinária, Instituto Superior de Agronomia, Instituto Superior de Economia e Gestão, Instituto Superior de Ciências Sociais e Políticas , Faculdade de Motricidade Humana, Faculdade de Arquitectura. O Instituto Superior Técnico, igualmente Escola Da UTL, tem repositório independente.

DEF - Artigos de Revistas

Mostrando recursos 1 - 20 de 67

  1. Bark anatomy, chemical composition and ethanol-water extract composition of Anadenanthera peregrina and Anadenanthera colubrina

    Mota, Graciene S.; Sartori, Caroline J.; Miranda, Isabel; Quilhó, Teresa; Mori, Fábio Akira; Pereira, Helena
    The bark of Anadenanthera peregrina (L.) Speg and Anadenanthera colubrina (Vell.) Brenan were characterized in relation to anatomical and chemical features. The barks were similar and included a thin conducting phloem, a largely dilated and sclerified non-conducting phloem, and a rhyridome with periderms with thin phellem interspersed by cortical tissues. Only small differences between species were observed that cannot be used alone for taxonomic purposes. The summative chemical composition of A. peregrina and A. colubrina was respectively: 8.2% and 7.7% ash; 28.8% and 29.3% extractives; 2.4% and 2.6% suberin; and 18.9% lignin. The monosaccharide composition showed the predominance of glucose (on average 82% of total neutral sugars) and...

  2. Green spaces are not all the same for the provision of air purification and climate regulationservices: the case of urban parks

    Vieira, Joana; Matos, Paula; Mexia, Teresa; Silva, Patrícia; Lopes, Nuno; Freitas, Catarina; Correia, Otília; Santos-Reis, Margarida; Branquinho, Cristina; Pinho, Pedro
    The growing human population concentrated in urban areas lead to the increase of road traffic and artificial areas, consequently enhancing air pollution and urban heat island effects, among others. These environmental changes affect citizen's health, causing a high number of premature deaths, with considerable social and economic costs. Nature-based solutions are essential to ameliorate those impacts in urban areas. While the mere presence of urban green spaces is pointed as an overarching solution, the relative importance of specific vegetation structure, composition and management to improve the ecosystem services of air purification and climate regulation are overlooked. This avoids the establishment of optimized planning and management procedures...

  3. Variation of ring width and wood density in two unmanaged stands of the Mediterranean oak Quercus faginea

    Sousa, Vicelina B.; Louzada, José Luís; Pereira, Helena
    Ring width and wood density variation were studied from pith-to-bark and along the stem in two naturally regenerated stands of Quercus faginea Lam. in Portugal. Ring width was significantly different between sites, in both heartwood and sapwood rings, ranging from 1.83 mm to 2.52 mm and from 0.77 mm to 2.11 mm, respectively. Wood density was significantly different between sites only in the heartwood, i.e., 914 kg m??3 and 1037 kg m??3. Site effects were the main source of variation for ring width and wood density within the heartwood as well as for sapwood ring width, while the between-tree effects explained more the density variation within...

  4. Milk production as an indicator of drought vulnerability of cities located in the brazilian semiarid region

    Andrade, Tafnes da S.; Cunha, John E. de B.L.; Galvão, Carlos de O.; Rufino, Iana A.A.
    Several spectral indices have been used to estimate droughts, however, these indicators only give evidence of a dry spell leaving out its impacts on significant economic activities performed in a given region. In this context, livestock breeding in one of the most important activities to analyze in the Brazilian semiarid region. The aim of this study was to evaluate the relationship between the drought indices, obtained through remote sensory devices, and annual milk production (2004 – 2014), identifying the most affected cities by the drought and were considered the most vulnerable and in need of special attention during dry periods....

  5. Burned area mapping in the brazilian savanna using a one-class support vector machine trained by active fires

    Pereira, Allan A.; Pereira, José Miguel Cardoso; Libonati, Renata; Oom, Duarte; Setzer, Alberto W.; Morelli, Fabiano; Machado-Silva, Fausto; Carvalho, Luís Marcelo Tavares de
    We used the Visible Infrared Imaging Radiometer Suite (VIIRS) active fire data (375 m spatial resolution) to automatically extract multispectral samples and train a One-Class Support Vector Machine for burned area mapping, and applied the resulting classification algorithm to 300-m spatial resolution imagery from the Project for On-Board Autonomy-Vegetation (PROBA-V). The active fire data were screened to prevent extraction of unrepresentative burned area samples and combined with surface reflectance bi-weekly composites to produce burned area maps. The procedure was applied over the Brazilian Cerrado savanna, validated with reference maps obtained from Landsat images and compared with the Collection 6 Moderate Resolution Imaging Spectrometer (MODIS) Burned Area product (MCD64A1)...

  6. Disturbance distance: quantifying forests' vulnerability to disturbance under current and future conditions

    Dolan, Katelyn A.; Hurtt, George C.; Flanagan, Steve A.; Fisk, Justin P.; Sahajpal, Ritvik; Huang, Chengquan; Le Page, Yannick; Dubayah, Ralph; Masek, Jeffrey G.
    Disturbances, both natural and anthropogenic, are critical determinants of forest structure, function, and distribution. The vulnerability of forests to potential changes in disturbance rates remains largely unknown. Here, we developed a framework for quantifying and mapping the vulnerability of forests to changes in disturbance rates. By comparing recent estimates of observed forest disturbance rates over a sample of contiguous US forests to modeled rates of disturbance resulting in forest loss, a novel index of vulnerability, Disturbance Distance, was produced. Sample results indicate that 20% of current US forestland could be lost if disturbance rates were to double, with southwestern forests showing highest vulnerability. Under a future climate...

  7. Importance of considering riparian vegetation requirements for the long-term efficiency of environmental flows in aquatic microhabitats

    Rivaes, Rui; Boavida, Isabel; Santos, José M.; Pinheiro, António N.; Ferreira, Maria Teresa
    Environmental flows remain biased toward the traditional biological group of fish species. Consequently, these flows ignore the inter-annual flow variability that rules species with longer lifecycles and therefore disregard the long-term perspective of the riverine ecosystem. We analyzed the importance of considering riparian requirements for the long-term efficiency of environmental flows. For that analysis, we modeled the riparian vegetation development for a decade facing different environmental flows in two case studies. Next, we assessed the corresponding fish habitat availability of three common fish species in each of the resulting riparian landscape scenarios. Modeling results demonstrated that the environmental flows disregarding riparian vegetation requirements promoted riparian degradation, particularly vegetation encroachment. Such circumstance altered the hydraulic characteristics...

  8. Functional redundancy and sensitivity of fish assemblages in European rivers, lakes and estuarine ecosystems

    Teichert, Nils; Lepage, Mario; Sagouis, Alban; Borja, Angel; Chust, Guillem; Ferreira, Maria Teresa; Pasquaud, Stéphanie; Schinegger, Rafaela; Segurado, Pedro; Argillier, Christine
    The impact of species loss on ecosystems functioning depends on the amount of trait similarity between species, i.e. functional redundancy, but it is also influenced by the order in which species are lost. Here we investigated redundancy and sensitivity patterns across fish assemblages in lakes, rivers and estuaries. Several scenarios of species extinction were simulated to determine whether the loss of vulnerable species (with high propensity of extinction when facing threats) causes a greater functional alteration than random extinction. Our results indicate that the functional redundancy tended to increase with species richness in lakes and rivers, but not in estuaries. We demonstrated that i) in the three...

  9. Comprehensive analysis of the cork oak (Quercus suber) transcriptome involved in the regulation of bud sprouting

    Usié, Ana; Simões, Fernanda; Barbosa, Pedro; Meireles, Brígida; Chaves, Inês; Gonçalves, Sónia; Folgado, André; Almeida, Maria Helena; Matos, José; Ramos, António M.
    Cork oaks show a high capacity of bud sprouting as a response to injury, which is important for species survival when dealing with external factors, such as drought or fires. The characterization of the cork oak transcriptome involved in the different stages of bud sprouting is essential to understanding the mechanisms involved in these processes. In this study, the transcriptional profile of different stages of bud sprouting, namely (1) dormant bud and (2) bud swollen, vs. (3) red bud and (4) open bud, was analyzed in trees growing under natural conditions. The transcriptome analysis indicated the involvement of genes related with energy production (linking the TCA...

  10. Synergy between land use and climate change increases future risk in Amazon forests

    Le Page, Yannick; Morton, Douglas; Hartin, Corinne; Bond-Lamberty, Ben; Pereira, José Miguel Cardoso; Hurtt, George; Asrar, Ghassem
    Tropical forests have been a permanent feature of the Amazon basin for at least 55 million years, yet climate change and land use threaten the forest’s future over the next century. Understory forest fires, which are common under the current climate in frontier forests, may accelerate Amazon forest losses from climatedriven dieback and deforestation. Far from land use frontiers, scarce fire ignitions and high moisture levels preclude significant burning, yet projected climate and land use changes may increase fire activity in these remote regions. Here, we used a fire model specifically parameterized for Amazon understory fires to examine the interactions between anthropogenic activities and climate under...

  11. The role of river morphodynamic disturbance and groundwater hydrology as driving factors of riparian landscape patterns in mediterranean rivers

    Rivaes, Rui; Pinheiro, António N.; Egger, Gregory; Ferreira, Teresa
    Original Research

  12. Os fogos florestais e a engenharia militar

    Costa, A. Maia e

  13. First interspecific genetic linkage map for Castanea sativa x Castanea crenata revealed QTLs for resistance to Phytophthora cinnamomi

    Santos, Carmen; Nelson, Charles Dana; Zhebentyayeva, Tetyana; Machado, Helena; Gomes-Laranjo, José; Costa, Rita Lourenço
    Research Article

  14. An operational approach to high resolution agro-ecological zoning in West-Africa

    Le Page, Y.; Vasconcelos, Maria; Palminha, A.; Melo, I.Q.; Pereira, J.M.C.
    Research Article

  15. Can heat waves change the trophic role of the world's most invasive crayfish ? Diet shifts in Procambarus clarkii

    Carreira, Bruno M.; Segurado, Pedro; Laurila, Anssi; Rebelo, Rui
    Research Article

  16. Storage stability of Jatropha curcas L. oil naturally rich in gamma-tocopherol

    Rodrigues, Joana; Miranda, Isabel; Furquim, Leonnardo; Gominho, Jorge; Vasconcelos, Manuel; Barradas, Gonçalo; Pereira, Helena; Bianchi-de-Aguiar, Fernando; Ferreira-Dias, Suzana
    tJatropha curcas L. is an interesting tropical oil crop for biodiesel production. However, seed conservationuntil oil extraction may be a problem under high temperature and humidity. In this study, Jatropha curcasL. seeds grown in Mozambique and presenting 160 mg/kg of gamma-tocopherol in their oil were storedfor 42 days, in dark, at 35◦C and 75% or 92% relative humidity (RH). Along storage, the oil was extractedand analysed in terms of fatty acid composition, tocopherol content, acidity, initial and final oxidationproducts (monitored by K232 and K270 values, respectively).Jatropha seeds presented an initial water content of 8.4% and an oil content of 45.7%...

  17. Effects of an extremely dry winter on net ecosystem carbon exchange and tree phenology at cork oak woodland

    Costa-e-Silva, Filipe; Correia, Alexandra C.; Piayda, Arndt; Dubbert, Maren; Rebmann, Corinna; Cuntz, Matthias; Werner, Christiane; David, Jorge Soares; Pereira, João Santos
    In seasonally dry climates, such as the Mediterranean, lack of rainfall in the usually wet winter may originate severe droughts which are a main cause of inter-annual variation in carbon sequestration. Leaf phenology variability may alter the seasonal pattern of photosynthetic uptake, which in turn is determined by leaf gas exchange limitations. The current study is based on the monitoring of an extremely dry winter in an evergreen cork oak woodland under the Mediterranean climate of central Portugal. Results are focused on net ecosystem CO2 exchange (NEE), phenology and tree growth measurements during two contrasting years: 2011, a wet year with a typical summer drought pattern...

  18. Classification modeling based on surface porosity for the grading of natural cork stoppers for quality wines

    Oliveira, Vanda; Knapic, Sofia; Pereira, Helena
    tThe natural cork stoppers are commercially graded into quality classes according with the homogeneity of theexternal surface. The underlying criteria for this classification are subjective without quantified criteria and standardsdefined by cork industry or consumers. Image analysis was applied to premium, good and standard quality classes tocharacterize the surface of the cork stoppers and stepwise discriminant analysis (SDA) was used to build predictiveclassification models. The final goal is to analyze the contribution of each porosity feature and propose an algorithmfor cork stoppers quality class classification. This study provides the knowledge based on a large sampling to anaccurate grading of natural...

  19. Chemical composition and kraft pulping potential of 12 eucalypt species

    Neiva, Duarte; Fernandes, Luís; Araújo, Solange; Lourenço, Ana; Gominho, Jorge; Simões, Rogério; Pereira, Helena
    Eucalypts are among the most important short-rotation hardwoods, planted worldwide for the pulp and paper industry. Even though the genus comprises over 700 species, only about a dozen species are used for pulping purposes, therefore, showing the potential for diversification. Six-year-old eucalypt trees from 12 species (Eucalyptus botryoides, Eucalyptus camaldulensis, Eucalyptus globulus, Eucalyptus grandis, Corymbia maculata, Eucalyptus ovata, Eucalyptus propinqua, Eucalyptus resinifera, Eucalyptus rudis, Eucalyptus saligna, Eucalyptus sideroxylon, and Eucalyptus viminalis) were analyzed for chemical composition, fiber morphological, pulping and handsheet paper properties to determine their kraft pulping suitability. The 12 species showed substantial differences regarding extractives (6.1–18.9%), lignin (21.6–30.8%) and holocellulose content (55.4–70.1%). The high inter-species variation...

  20. Sensory impact of alternative ageing technology for the production of wine brandies

    Caldeira, Ilda; Anjos, Ofélia; Belchior, A. Pedro; Canas, Sara
    The production of wine brandies requires their stage in wooden barrels, for a minimum period of time, a process called ageing or maturation. Due to the high cost of this process, alternative technologies are being studied in order to accelerate the ageing process, such as the use of wood fragments inside of stainless steel tanks. The present work evaluates the influence of different ageing technologies on the sensory profile of the brandy. A brandy was aged, during two years, in 650 L wooden barrels and in 3000 L stainless steel tanks. Both had Limousin oak (Quercus robur) and Portuguese chestnut staves (Castanea sativa). The...

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