1,089 research outputs found

    Attack intensity of Corythucha ciliata (Hemiptera, Tingidae) on Platanus spp. in an urban area in Portugal: a comparison between pruned and unpruned trees.

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    Corythucha ciliata (Say, 1832), commonly known as sycamore lace bug (SLB), is an insect species native to North America. Since its accidental introduction in Europe (through Italy) in 1964, it has expanded across most European countries. The arrival of SLB in Portugal is uncertain but its distribution is wide. Sycamore (Platanus spp.), the only host of SLB, is one of the most widespread and important urban tree species in Portugal. It provides a wide range of environmental, social and economical benefits, which have been threatened by the invasion of this pest. SLB damages trees by feeding on the underside of the leaves causing discoloration and eventually premature senescence. While the long-term effect of SLB on the health of urban trees is yet to be fully assessed, there is compelling evidence that pruning further increases SLB damage. In this study we assessed the impact of pruning on the attack intensity of SLB. To test the hypothesis that pruning promotes the invasion of SLB, we compared the intensity of attack of pruned trees with unpruned trees. We collected sycamore leaves from pruned and unpruned trees and then assessed the intensity of attack by scaling damage by visual rating. Our findings show that pruned trees exhibit significantly higher attack intensities than unpruned trees (p < 0,001, χ2 goodness of fit). Based on these findings we recommend that sycamore pruning should be performed with caution (or even ceased), especially in urban areas where SLB is present

    Plasmodium species mixed infections in two areas of Manhiça District, Mozambique

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    We compared the distribution patterns of individual Plasmodium species and mixed-species infections in two geographically close endemic areas, but showing environmental differences. Comparisons concerned circulating Plasmodium infections in both human and mosquito vector populations in the dry and wet seasons, at a micro-epidemiological level (households). Both areas revealed a very high overall prevalence of infection, all year-round and in all age groups. Plasmodium falciparum was the predominant species, being found in the vast majority of infected individuals regardless of the presence of other species. Plasmodium malariae and Plasmodium ovale occurred almost exclusively in mixed infections. Seasonal variation in P. malariae prevalence was observed in one area but not in the other. A decrease in P. malariae prevalence concurred with a marked increase of P. falciparum prevalence. However this was strongly dependent on age and when analysing infections at the individual level, a different pattern between co-infecting species was unveiled. Regarding transmission patterns, in both areas, P. falciparum gametocytes predominated in single infections regardless of age and P. malariae gametocyte carriage increased when its overall prevalence decreased

    Linear and nonlinear models in wind resource assessment and wind turbine micro-siting in complex terrain

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    The current trend of increasing the electricity production from wind energy has led to the installation of wind farms in areas of greater orographic complexity, raising doubts on the use of simple, linear, mathematical models of the fluid flow equations, so common in the wind energy engineering. The present study shows how conventional techniques, linear models and cup anemometers, can be combined with flow simulation by computational fluid dynamics techniques (nonlinear models) and measurements by sonic anemometers, and discuss their relative merits in the characterisation of the wind over a coastal region—a cliff over the sea. The computational fluid dynamic techniques were particularly useful, providing a global view of the wind flow over the cliff and enabling the identification of separated flow regions, clearly unsuitable for installation of wind turbines. These locations display a pulsating flow, with periods between 1 and 7min, in agreement with sonic anemometer measurements, and both a turbulence intensity and a gust factor well above the wind turbine design conditions.The authors acknowledge the support of the Portuguese Foundation for Science and Technology (FCT), under research Project TURBWIND (POCI/ENR/60965/2004). Data from the field experiment were kindly supplied by EEM-Empresa de Electricidade da Madeira, SA.info:eu-repo/semantics/publishedVersio

    Collembolan morphospecies (Hexapoda: Collembola) in serpentine soils: a case study in a natural ecosystem in northeastern Portugal

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    Serpentine soils represent challenging habitats for plants and soil dwelling organisms, such as collembolans, because they typically exhibit high levels of heavy metals (e.g. chromium, cobalt, and nickel). Serpentinized areas cover about 8000 ha in Northeastern Portugal. While the plant communities are well studied, the collembolans are virtually unknown. The data presented here represent the first effort to describe the structure of a collembolan community, using morphospecies as a surrogate of species, in a serpentinized area occupied by a natural forest of Quercus rotundifolia and Quercus faginea located nearby Bragança (Portugal). Sampling was performed during the last week of September of 2008 in a serpentinized area near Bragança (Portugal). At each of the 29 sampling points (distributed along two transects) collembolans were collected with a soil core (5 cm diameter x 10 cm depth). The collembolans were extracted from the soil (using a McFadyen apparatus), sorted, counted and finally identified to morphospecies level. The number of morphospecies observed was 37. The total abundance in the mineral horizon (1862 individuals) was not significantly different from the organic horizon (1883 individuals). The Simpson Diversity Index and Richness were higher in the organic horizon (21.7 and 35 species, respectively) than in the mineral horizon (9.9 and 30 species, respectively). The species accumulation curves showed that the estimated number of morphospecies for the mineral horizon is 36 while for the organic horizon is 38

    Biological invasion of Corythucha ciliata in green urban spaces in Portugal: a niche modeling approach using maximum entropy

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    Corythucha ciliata (Hemiptera: Tingidae) é um inseto nativo da América do Norte que foi introduzido na Europa, pela Itália, em 1964. Desde então tem se expandido por toda a Europa, desconhecendo-se a data de chegada e a sua área de distribuição em Portugal. Esta importante praga invasora alimenta-se na face inferior das folhas de plátano, uma das mais importantes árvores ornamentais nos espaços verdes urbanos em Portugal, causando senescência prematura e eventualmente morte, em casos de infestações severas consecutivas. A modelação de nicho está se tornando uma ferramenta cada vez mais importante na gestão de invasões biológicas, tanto antes como depois da introdução do organismo invasor. Neste estudo, o software MaxEnt (máxima entropia) foi usado na modelação da distribuição invasiva potencial de Corythucha ciliata em Portugal, a partir de um conjunto de variáveis ambientais e de dados de presença do inseto, obtidos a partir da observação de folhas de plátanos amostrados por todo o país. De acordo com o melhor modelo gerado pelo MaxEnt, as áreas de maior adequabilidade potencial à invasão de Corythucha ciliata encontram-se no norte de Portugal apresentando o sul e as regiões de maior altitude do norte e centro adequabilidade reduzida ou nula. Observações laboratoriais da biologia de Corythucha ciliata aliadas aos registos de ausência em várias localidades do sul de Portugal e ocorrência predominante na metade norte de Espanha suportam o modelo desenvolvido. Porém, a validação do modelo requer futuras prospecções nas áreas de reduzida adequabilidade e onde a praga se encontrava virtualmente ausente no momento em que foi realizada a amostragem. Os modelos de adequabilidade podem ser usados como ferramenta auxiliar na tomada de decisão no que concerne à gestão dos espaços verdes

    Collembolan communities in a sustainable system for production of woody biomass for energy: abundance and diversity of morphospecies.

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    Woody biomass for energy obtained from short rotation woody crops (SRWC) needs to be managed in a sustainable way, thus allowing ecosystem conservation. However, there is a gap in our knowledge concerning the effects of these crops on soil organisms, of which collembolans represent a good indicator of soil quality. On the other hand, soil biological sciences are strongly affected by the taxonomic skill crisis, with many groups of soil animals suffering from a taxonomic impediment in terms of identification. This problem can be reduced by using a para-taxonomic approach where morphospecies can be used as surrogates of taxonomic species. The objective of this work was to study the structure of collembolan communities in a SRWC experimental field using morphospecies. Abundance, richness, evenness and diversity indexes were used to describe the structure of the collembolan community and species accumulation curves were computed to estimate species richness in the study area. Prior to the installation of the SRWC, 106 soil samples were collected at each defined sampling point (distributed along 14 transects) using a soil core (5 cm diameter x 10 cm depth). In the laboratory, collembolans were extracted from the soil (using a McFadyen apparatus), sorted, counted and finally identified to morphospecies level. The number of morphospecies observed was 34, representing a total abundance of 3221 collembolans. The Simpson Diversity Index and richness were 27and 34, respectively. The species accumulation curves showed that the estimated number of morphospecies was 38

    Radiation Damage of Polycrystalline CVD Diamond with Graphite Electrical Contacts

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    In this work we show preliminary results of radiation damage for a polycrystalline diamond with graphite contacts in terms of time response after 62 MeV protons irradiation for a total fluence of (2.0±0.08)×1015 protons/cm2. In addition, we describe the realization of a new type of device made with graphite micro-strips by laser micro-writing on diamond surface. In this way we made 20 graphite micro-strips of width about 87 m and spacing between each other of about 60 μ\mum

    Project Proof: Internet Enabled Process Reengineering at J.D. Edwards & Company

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    J.D. Edwards is a provider of the new generation of ERP and collaborative commerce solutions. This case study describes the challenges faced internally by the company to upgrade to the latest enterprise software it would sell to the world. Dubbed Project PROOF, the project started in June 2001 and was completed in November 2002. The perspectives of the CIO, the program manager, and other key personnel are presented. The case study highlights the issues that arise in an enterprise software implementation project. In addition, the case touches upon issues of project management, process redesign, and marketing. The case study uses a multimedia format to add richness and detail. Although J.D. Edwards was acquired in 2003, the issues discussed are relevant to current business practices

    Tuberculose disseminada com manifestações cerebrais, pulmonares, ganglionares e intestinais em raposas

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    Tuberculose disseminada com manifestações cerebrais, pulmonares, ganglionares e intestinais em raposas

    CO053. O IMPACTO DOS ANDROGÉNIOS NA RESISTÊNCIA ÓSSEA DE HOMENS NORMAIS.

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