Time filter

Source Type

Pereira S.,University of Lisbon | Costa M.,University of Lisbon | da Graca Carvalho M.,University of Lisbon | Rodrigues A.,Instituto Nacional Of Investigacao Agraria E Veterinaria
Energy Conversion and Management | Year: 2016

This manuscript examines the potential of poplar short rotation coppice cultivation for bioenergy in the Alentejo region, Southern Portugal. The biomass is intended to fulfil, at least, 10% (energy basis) of the fuel needs of two Portuguese coal-fired power plants (Sines and Pego), using co-firing technology. The study considers the overall production chain from cradle to power plant gate, cultivated in scrubland areas with duration of 12 years, harvested every three years and with 6667 plants per ha, covering a land area of about 52,250 ha. Three different biomass annual yields are assumed. The results show that the biomass selling prices range from 76.9 to 120.5 Euro ton−1, to match the production costs. The net energy of the overall project ranges from 34.7 to 75.4 PJ and the project cost from 619 to 823.9 MEuro. The main environmental impact of the project is the reduction of the CO2 emissions due to the biomass co-firing, instead of burning coal alone. The power plants can reduce CO2 emissions over the project lifetime between 8.2% and 16.5% of the current values. The financial analysis demonstrates that the project is not financially feasible without external grants, but a policy scenario of carbon allowances trading may be instrumental on turning it financially feasible, depending on allowances and coal market prices. Finally, with a reduction of 50% in the main costs, the project becomes financially feasible under a CO2 emissions trading scenario for a biomass yield of 20 dry ton ha−1 per year. © 2016 Elsevier Ltd


Resende A.,University of Lisbon | Catarino S.,Instituto Nacional Of Investigacao Agraria E Veterinaria | Geraldes V.,University of Lisbon | De Pinho M.,University of Lisbon
Industrial and Engineering Chemistry Research | Year: 2013

This work aims to develop a process of ultrafiltration in diafiltration mode to concentrate the fraction of white wine polysaccharides of high molecular weight (arabinogalactan-proteins and mannoproteins) and to purify this fraction in terms of polyphenols, organic acids, and minerals removal. The membrane ETNA 10PP from AlfaLaval was characterized by an hydraulic permeability, Lp, of 105 L/(h·m2·bar) and a molecular weight cutoff, MWCO, of 17 kDa. A membrane surface area of 0.036 m2 was installed in a Lab-Unit M20 from Alva Laval. The permeation operating conditions, in total recirculation mode, were a temperature of 25 C, pressures ranging from 0.5 to 5 bar, and an average velocity of 0.94 m/s. The ultrafiltration in concentration mode was run up to concentration factors of 4.25, and when diafiltration was introduced the concentration factors went up to 6.3. The permeate fluxes were maintained at an average value of 58 L/(h·m2). © 2013 American Chemical Society.


Costa A.,New University of Lisbon | Costa A.,Instituto Nacional Of Investigacao Agraria E Veterinaria | Madeira M.,University of Lisbon | Plieninger T.,Copenhagen University
Applied Geography | Year: 2014

The cork oak (Quercus suber L.) woodlands of the agroforestry landscapes of Southwestern Iberia are undergoing drastic change due to severe natural and anthropogenic disturbances. These may eventually result in woodland loss or deforestation, the final step of an ongoing process of woodland degradation. Monitoring changes in the spatial patterns of woodlands - especially fractional canopy cover of woodlands and/or their patchiness in the landscape mosaic - potentially enables forecasting of loss and responding to it at an early stage. We examine the degradation process in two cork oak woodlands, resulting from distinct disturbances, wildfire and oak mortality, aimed at evaluating the changes, trends and deviations of the spatial attributes of these woodlands as they move from an initial (less disturbed ecosystem) to a final state (more disturbed ecosystem). While undergoing disturbances, both woodlands exhibited similar trends of decreasing fractional canopy cover and decreasing number of larger patches. Patchiness rather than fractional canopy cover seems, however, to be potentially more useful as a signature of imminent oak woodlands deforestation, given that its contrast before and after disturbance was much higher. The structural dynamics of oak woodlands is a crucial but neglected issue that needs greater attention from policy forums working toward their conservation and restoration as well as from stakeholders and society as a whole. © 2014 Elsevier Ltd.


Ferreira M.I.,University of Lisbon | Silvestre J.,Instituto Nacional Of Investigacao Agraria E Veterinaria | Conceicao N.,University of Lisbon | Malheiro A.C.,University of Trás os Montes e Alto Douro
Irrigation Science | Year: 2012

Projected climate changes and expansion of viticulture to drier regions justify the installation and management of deficit irrigation (DI) strategies. Contradictory results on the effect of DI on crops may be ascribed to the incorrect application of these techniques. The lack of discrimination between basal crop (Kcb) and stress coefficients (Ks) can be an obstacle to proper irrigation management. A sap flow (SF) technique associated with microlysimeters and eddy covariance (EC) methods was applied to five commercial vineyards, aiming to discriminate those coefficients, during the driest period of the vegetative cycle. A comparative analysis of the coefficients, in relation to measured vegetation parameters (for Kcb) and plant water status (for Ks) is presented. Kcb, ranging from about 0.35 to 0.75, was highly correlated with leaf area index at stand level. Ks, which decreased till 0.2 in the most stressed vineyard, was well correlated to plant water status (Ks function), represented by predawn leaf water potential. Ks functions for the different experiments exhibited falling slopes with decreasing water status, with variable trends depending on the rates of maximal crop transpiration (Tm). These experimental results show that specific parameters for Ks functions, necessary to estimate water use and irrigation depths, in order to control the stress levels in DI scheduling, are also dependent on Tm. © 2012 Springer-Verlag.


Rosa A.M.M.,IBB Institute for Biotechnology And Bioengineering | Louro A.F.,IBB Institute for Biotechnology And Bioengineering | Martins S.A.M.,IBB Institute for Biotechnology And Bioengineering | Inacio J.,Instituto Nacional Of Investigacao Agraria E Veterinaria | And 2 more authors.
Analytical Chemistry | Year: 2014

Microfluidic paper-based analytical devices (μPADs) fabricated by wax-printing are suitable platforms for the development of simple and affordable molecular diagnostic assays for infectious diseases, especially in resource-limited settings. Paper devices can be modified for biological assays by adding appropriate reagents to the test areas. For this purpose, the use of affinity immobilization strategies can be a good solution for bioactive paper fabrication. This paper describes a methodology to capture labeled-DNA strands and hybrids on paper via the anchoring of antibodies with a fusion protein that combines a family 3 carbohydrate binding module (CBM) from Clostridium thermocellum, with high affinity to cellulose, and the ZZ fragment of the staphyloccocal protein A, which recognizes IgG antibodies via their Fc portion. Antibodies immobilized via CBM-ZZ were able to capture appropriately labeled (biotin, fluorescein) DNA strands and DNA hybrids. The ability of an antibody specific to biotin to discriminate complementary from noncomplementary, biotin-labeled targets was demonstrated in both spot and microchannel assays. Hybridization was detected by fluorescence emission of the fluorescein-labeled DNA probe. The efficiency of the capture of labeled-DNA by antibodies immobilized on paper via the CBM-ZZ construct was significantly higher when compared with a physical adsorption method where antibodies were simply spotted on paper without the intermediation of other molecules. The experimental proof of concept of wax-printed μPADs functionalized with CBM-ZZ for DNA detection at room temperature presented in this study constitutes an important step toward the development of easy to use and affordable molecular diagnostic tests. © 2014 American Chemical Society.


Correa M.J.,CONICET | Ferrero C.,CONICET | Puppo C.,CONICET | Puppo C.,National University of La Plata | Brites C.,Instituto Nacional Of Investigacao Agraria E Veterinaria
Food Hydrocolloids | Year: 2013

Pasting and gelatinization behavior of rice gels from Japonica (Ariete, Euro), Indica (Gladio, Suriname) and waxy (Glutinous) varieties were analyzed. These varieties differ widely in amylose contents and differential scanning calorimetry (DSC) gelatinization temperatures. Besides, the effect of locust bean gum (LBG) addition and the impact of successive viscoanalyser multiple-heating-cooling and freezing-thawing cycles on the gels pasting viscosities (peak-ηpeak, trough-ηmin, final-ηfinal), viscoelasticity by oscillatory rheometry and syneresis were evaluated.Flours from different rice varieties exhibited distinct viscoanalyser curves and viscoelastic behaviors as well as different degree of syneresis. Euro and Ariete showed lower setback from peak (ηfinal-ηpeak) and syneresis, whereas Waxy had ηpeak superior to ηfinal (negative setback) and did not exhibit syneresis.The addition of LBG (0.5%, 1%, 2% w/w) significantly modified the pasting viscosities in single and multiple profiles, viscoelastic and syneresis properties of rice gels and the extent of the effect was dependent of rice varieties. In general, the addition of LBG caused an increase in peak, final and minimum viscosities but only rice gel from Ariete variety exhibited reduction of setback. Reduction of syneresis seems evident for 0.5% LBG addition on rice gels from Suriname and Ariete varieties, but 1% was needed for Gladio variety.Successive multiple-heating-cooling cycles led to a progressive decrease on viscosity after a second cycle for Japonica and Waxy varieties, in Indica varieties these peak viscosities were maintained or decreased in a lesser degree, syneresis was higher than in single cycles and is largely reduced in the presence of LBG.This study provides knowledge of different rheological behavior of rice varieties that would be relevant for utilization of rice gels on food applications. © 2012 Elsevier Ltd.


Sun B.,Instituto Nacional Of Investigacao Agraria E Veterinaria | Sa M.D.,Instituto Nacional Of Investigacao Agraria E Veterinaria | Leandro C.,Instituto Nacional Of Investigacao Agraria E Veterinaria | Caldeira I.,Instituto Nacional Of Investigacao Agraria E Veterinaria | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2013

Recent studies have indicated the presence of significant amount of highly polymerized and soluble proanthocyanidins in red wine and such compounds interacted readily with proteins, suggesting that they might be particularly astringent. Thus, the objective of this work was to verify the astringency of polymeric proanthocyanidins and their contribution to red wine astringency. The precipitation reactions of the purified oligomeric procyanidins (degree of polymerization ranging from 2 to 12-15) and polymeric procyanidins (degree of polymerization ranging from 12-15 to 32-34) with human salivary proteins were studied; salivary proteins composition changes before and after the reaction was verified by SDS-PAGE and procyanidins composition changes by spectrometric, direct HPLC and thiolysis-HPLC methods. The astringency intensity of these two procyanidin fractions was evaluated by a sensory analysis panel. For verifying the correlation between polymeric proanthocyanidins and young red wine astringency, the levels of total oligomeric and total polymeric proanthocyanidins and other phenolic composition in various young red wines were quantified and the astringency intensities of these wines were evaluated by a sensory panel. The results showed that polymeric proanthocyanidins had much higher reactivity toward human salivary proteins and higher astringency intensity than the oligomeric ones. Furthermore, young red wine astringency intensities were highly correlated to levels of polymeric proanthocyanidins, particularly at low concentration range (correlation coefficient r = 0.9840) but not significant correlated to total polyphenols (r = 0.2343) or other individual phenolic compounds (generally r < 0.3). These results indicate the important contribution of polymeric proanthocyanidins to red wine astringency and the levels of polymeric polyphenols in red wines may be used as an indicator for its astringency. © 2013 American Chemical Society.


Canas S.,Instituto Nacional Of Investigacao Agraria E Veterinaria | Caldeira I.,Instituto Nacional Of Investigacao Agraria E Veterinaria | Belchior A.P.,Instituto Nacional Of Investigacao Agraria E Veterinaria
Food Chemistry | Year: 2013

This study provides innovative information on the influence of new technologies of ageing (stainless steel tanks with wood staves or wood tablets of chestnut or Limousin oak), in comparison with traditional technology (oak wooden barrels), on the extraction/oxidation kinetics of low molecular weight compounds of wine brandy. The brandy was sampled and analysed by HPLC during the first year of ageing. The results show that most of the compounds tend to increase over the time, but their extraction/oxidation kinetics depend on the ageing technology. The wooden barrels promote greater enrichment in the majority of the compounds. However, gallic acid, ellagic acid and syringaldehyde, and vanillin and 5-methylfurfural, which are strong antioxidants and key-odourant compounds, respectively, present higher contents in the brandy aged with the alternative technologies. Chestnut proves to be a suitable alternative to Limousin oak for the ageing of brandy in all the studied technologies, inducing faster evolution and high quality. © 2013 Elsevier Ltd. All rights reserved.


Mateus C.,Instituto Nacional Of Investigacao Agraria E Veterinaria
Bulletin of Insectology | Year: 2012

Spatial distribution and flight and predation activities of Coenosia attenuata Stein (Diptera Muscidae) adults were studied in greenhouse vegetable crops in the Oeste region, Portugal. During spring and summer, fewer flies were seen in the crops in the middle of the day in relation to the morning and afternoon periods. Males/ females ratio was 1:4, independently of the season. Flies were significantly more abundant in the sunny areas of crops in relation to the shadowed ones, and were found landed on cucumber and sweet pepper plants (especially on leaves), in opposition to tomato plants; in this crop, flies preferred the tutors and other greenhouse structures. Adults were also abundant next to the soil, on the plastic covering it and on irrigation pipes. Outside greenhouses, adults were landed everywhere. Most flies, when landed in the pending cucumber leaves, were next to their borders and oriented downwards. Some flights were trigged by insects flying inside a range of about 30 cm distance (here called "provoked flights"), and also by other movements made by the observer nearby. Insects landed on the same leaf as the predator, moving closely (but not flying), were not attacked. The majority of flights registered had no visible cause ("non-provoked flights"), some of them looking more like jumps. In 72% of provoked flights, flies returned to the leaf they had just left, and in almost half of them, they adopted both the location and the orientation they had before in the leaf. The percentage of preys captured was very low: many flights were probably the result of a territorial behaviour and not of a predation activity. Cannibalism was not detected in the field. Predation in the field occurred on whiteflies, small hymenopterans, leafhoppers, leafminers, sciarids, psocopterans, and also on thrips. Most preys were attacked in the cervix area.


Lourenco A.M.,University of Coimbra | Sequeira E.,Instituto Nacional Of Investigacao Agraria E Veterinaria | Sant'Ovaia H.,University of Porto | Gomes C.R.,University of Coimbra
Geoderma | Year: 2014

This study presents an application of environmental magnetism techniques for the characterisation of the soils near Coimbra (central Portugal). Magnetic measurements, scanning electron microscopy and geochemical studies were carried out on samples collected in 6 soil profiles in order to find possible relationships and to interpret environmental implications. Magnetic susceptibility, saturation isothermal remanent magnetisation and isothermal remanent magnetisation at the backfield of 100 mT and 300 mT were measured. HardIRM %, SIRM/. χ and S-ratios were also calculated. Polluted soils showed higher values of magnetic parameters in the superficial soil horizons closer to the roads, plants and urban areas. The lowest values were observed in the deeper horizons of the soil and in the areas least disturbed by human activity. The magnetic results also suggested that the magnetic signal of these soils is mainly influenced by ferrimagnetic magnetite-like minerals and with only a minor contribution from antiferromagnetic carriers (such as hematite minerals). In unpolluted soils, lithogenic contribution is reflected by the enhancement of magnetic susceptibility near parental rock material. Scanning electron microscope images of the topsoil samples revealed the presence of magnetic spherules typical of vehicular exhaust and combustion processes. This evidence suggests that the atmospheric deposition of fly ash is the main reason for the enhancement of the magnetic signal in the topsoil. Chemical analyses showed that the concentration of various heavy metals was higher than the mean background values for Portuguese soils, and higher in superficial soils. Heavy metals showed significant positive correlation with magnetic properties. The conclusions highlight the importance of using environmental magnetism methods and techniques in the evaluation process of soil evolution and pollution history throughout time. © 2013 Elsevier B.V.

Loading Instituto Nacional Of Investigacao Agraria E Veterinaria collaborators
Loading Instituto Nacional Of Investigacao Agraria E Veterinaria collaborators