270 research outputs found

    A tree-based approach for modelling interception loss from evergreen oak mediterranean savannas

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    Evaporation of rainfall intercepted by tree canopies is usually an important part of the overall water balance of forested catchments and there have been many studies dedicated to measuring and modelling rainfall interception loss. These studies have mainly been conducted in dense forests; there have been few studies on the very sparse forests which are common in dry and semi-arid areas. Water resources are scarce in these areas making sparse forests particularly important. Methods for modelling interception loss are thus required to support sustainable water management in those areas. In very sparse forests, trees occur as widely spaced individuals rather than as a continuous forest canopy. We therefore suggest that interception loss for this vegetation type can be more adequately modelled if the overall forest evaporation is derived by scaling up the evaporation from individual trees. The evaporation rate for a single tree can be estimated using a simple Dalton-type diffusion equation for water vapour as long as its surface temperature is known. From theory, this temperature is shown to be dependent upon the available energy and windspeed. However, the surface temperature of a fully saturated tree crown, under rainy conditions, should approach the wet bulb temperature as the radiative energy input to the tree reduces to zero. This was experimentally confirmed from measurements of the radiation balance and surface temperature of an isolated tree crown. Thus, evaporation of intercepted rainfall can be estimated using an equation which only requires knowledge of the air dry and wet bulb temperatures and of the bulk tree-crown aerodynamic conductance. This was taken as the basis of a new approach for modelling interception loss from savanna-type woodland, i.e. by combining the Dalton-type equation with the Gash’s analytical model to estimate interception loss from isolated trees. This modelling approach was tested using data from two Mediterranean savanna-type oak woodlands in southern Portugal. For both sites, simulated interception loss agreed well with the observations indicating the adequacy of this new methodology for modelling interception loss by isolated trees in savanna-type ecosystems. Furthermore, the proposed approach is physically based and requires only a limited amount of data. Interception loss for the entire forest can be estimated by scaling up the evaporation from individual trees accounting for the number of trees per unit area

    Observation of diffractive orbits in the spectrum of excited NO in a magnetic field

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    We investigate the experimental spectra of excited NO molecules in the diamagnetic regime and develop a quantitative semiclassical framework to account for the results. We show the dynamics can be interpreted in terms of classical orbits provided that in addition to the geometric orbits, diffractive effects are appropriately taken into account. We also show how individual orbits can be extracted from the experimental signal and use this procedure to reveal the first experimental manifestation of inelastic diffractive orbits.Comment: 4 fig

    Nd:YAG laser scribed zinc oxide on semi-flexible copper foils

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    In this work, a novel approach to synthesise zinc oxide (ZnO) directly on flexible copper substrates is proposed. The produced samples show a foam-like morphology made of agglomerates of small ZnO particles when processed at laser energy density of 18.0 J/cm2. On the other hand, the samples processed at higher beam energy density, i.e. 33.2 J/cm2, resulted in a more granular morphology, with some ZnO particles dispersed over the sample’s surface. Raman spectroscopy measurements demonstrated that this method resulted in the formation of wurtzite-ZnO crystalline phase in all samples. Room temperature photoluminescence spectroscopy analysis revealed the presence of a broad visible band in the orange-red region dominating the spectra, with a small contribution from the near band edge emission in the UV spectral region. Decreasing the beam energy fluence from 33.2 to 18.0 J/cm2 resulted in samples with higher overall visible band intensity, in line with what was observed for their crystalline quality. Moreover, the shift of the broad band maxima towards longer wavelengths could be an indication of the possibility of tuning the visible emission according to the chosen laser processing conditions.publishe

    Multiparasitism in Crab-eating fox (Cerdocyon thous) (Carnivora: Canidae), including new records, in the Brazilian Pampa - case report

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    ABSTRACT Cerdocyon thous is considered the most common wild canid in Rio Grande do Sul, and can serve as a host for several parasites, playing an important role in maintaining the biological cycle. Despite being a widespread and abundant species, they have a relatively little-known fauna of endo and ectoparasites, mainly focusing on the different regions of their occurrence. With this work, the objective was to report the multiparasitism in a specimen of C. thous in the Brazilian Pampa. Using modified Centrifuge-Flotation and Spontaneous Sedimentation techniques, a high taxonomic diversity of parasites was observed, and the finding of eggs compatible with Lagochilascaris spp. in C. thous in Brazil, in addition to Uncinaria spp. eggs and Cystoisospora spp. oocysts in the same host in the south of the country. The presence of eggs of different helminths in the feces of C. thous is extremely important, mainly for public health, but also for the knowledge of the biodiversity of parasites present in wild populations of canids, until then little studied, thus allowing the implementation of control programs

    Academics perception towards various water reuse options: University of Trás-os-Montes e Alto Douro - UTAD Campus (Portugal) as a case study

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    Any strategy of water reuse has to achieve social acceptance to be successful. This paper presents the results of a multiple choice survey that attempted to establish the general attitude toward water reuse by asking academics in UTAD (Portugal) a wide range of questions. The survey included 20 reuse options, which were clustered into three reuse categories, specifically: low, medium and high contact levels. Correlation analysis between the level of support of low, medium and high contact options and demographic characteristics, personal and environmental beliefs was performed. Results show that a high proportion of the participants supported low and medium contact reuse options. Correlation was found to exist between the income classes and to the level of support of medium and high reuse options and between education level and the support for high contact reuse options. The responses to the survey suggested that some beliefs influence the level of support

    The use of camu-camu (Myrciaria dubia) for the production of a fermented alcoholic beverage

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    The high levels of ascorbic acid in camu-camu (Myrciaria dubia McVaugh, Myrtaceae) have stimulated interest of extractivists, farmers and consumers. This has led to a need to develop adequate technology for it's production on non-flooded land and the industrial use of this fruit. This study had as its main objective to verify if camu-camu is adequate for the production of fermented alcoholic beverages, measuring the effect of blanching the fruit and the incorporation of the fruit peel with the fruit pulp on the nutritional and sensory characteristics of the drink. The fruits were separated into 4 groups, two being blanched (90 ºC for 7 minutes). After the pulp was removed, the peels of one group from each blanching treatment were incorporated into the respective pulps and their chemical composition evaluated. After sugar correction of the must, pasteurisation, fermentation (25 days), decanting, pasteurisation (70 ºC for 15 minutes), filtering and clarification, the beverages were evaluated as to their chemical composition, sweetened and submitted to sensory analysis. Blanching reduced the concentration of ascorbic acid in the pulps (33 %) and the addition of the peel increased the amount of dry matter (39 % in pulp), ascorbic acid (33 % in pulp, 23 % in must and 50 % in drink) and phenolic compounds (50 % in drink). The sensory profile and acceptability suggest that camu-camu is adequate for the production of fermented alcoholic beverages and that the addition of the peel to the pulp contributes positively to it's acceptability (6.7 with versus 6.2 without, of 9 points possible). The beverage had flavour characteristic of the fruit, a orangish-red color and agreeable taste.", 'enO elevado teor de ácido ascórbico no camu-camu (Myrciaria dubia McVaugh, Myrtaceae) desperta o interesse de extrativistas, agricultores e consumidores, e leva à necessidade de desenvolvimento de tecnologias adequadas para produção em terra firme e aproveitamento industrial do fruto. Este trabalho teve por objetivo verificar a adequação do camu-camu para a produção de bebida alcoólica fermentada, assim como o efeito do branqueamento do fruto e da incorporação da casca à polpa nas características nutricionais e sensoriais da bebida. Os frutos foram separados em quatro lotes, sendo dois branqueados (90 ºC por 7 min). Após a despolpa, as cascas de um lote de cada tratamento (com e sem branqueamento) foram incorporadas às respectivas polpas e avaliadas quanto à composição química (umidade, pH, acidez, sólidos solúveis, açúcares, ácido ascórbico, compostos fenólicos, antocianinas e flavonóides). Após a correção do mosto com açúcar, pasteurização, fermentação (25 dias), trasfega, pasteurização (70 ºC por 15 min), filtragem e clarificação, as bebidas foram avaliadas quanto a composição química, edulcoradas e submetidas à análise sensorial. O branqueamento reduziu a concentração de ácido ascórbico das polpas (33 %) e a agregação da casca aumentou os teores de matéria seca (39 % polpa), ácido ascórbico (33 % na polpa, 23 % no mosto e 50 % na bebida) e fenólicos (50 % bebida). O perfil sensorial e a aceitabilidade sugerem que o camu-camu é adequado para a produção de bebida alcoólica fermentada e que a agregação da casca à polpa contribuiu positivamente para a aceitabilidade (6,7 com casca e 6,2 sem casca, na escala de 9 pontos). As bebidas apresentaram flavor característico do fruto, limpidez, coloração vermelho-laranjada e sabor agradável
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