4,065 research outputs found

    SDN-AAA: Towards the standard management of AAA infrastructures

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    Software Defined Networking (SDN) is a widely deployed technology enabling the agile and flexible management of networks and services. This paradigm represents an appropriate candidate to address the dynamic and secure management of large and complex Authentication, Authorization and Accounting (AAA) infrastructures. In those infrastructures, there are several nodes which must exchange information securely to interconnect different realms. This article describes a novel SDN-based framework with a data model-driven approach following the standard YANG, named SDN-AAA, which can be used to dynamically manage routing and security configuration in AAA scenarios.Comment: 7 pages, 5 figure

    Reinforcing capability of cellulose nanocrystals obtained from pine cones in a biodegradable poly(3-hydroxybutyrate)/poly(e-caprolactone) (PHB/PCL) thermoplastic blend

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    [EN] In this work, different loads (3, 5 and 7 wt%) of pine cone cellulose nanocrystals (CNCs) were added to films of poly(3-hydroxybutyrate)/poly(epsilon-caprolactone) (PHB/PCL) blends with a composition of 75 wt% PHB and 25 wt % PCL (PHB75/PCL25). The films were obtained after solvent casting followed by melt compounding in an extruder and finally subjected to a thermocompression process. The influence of different CNCs loadings on the mechanical, thermal, optical, wettability and disintegration in controlled compost properties of the PHB75/PCL25 blend was discussed. Field emission scanning electron microscopy (FESEM) revealed the best dispersion of CNCs on the polymeric matrix was at a load of 3 wt%. Over this loading, CNCs aggregates were formed enhancing the films fragilization due to stress concentration phenomena. However, the addition of CNCs improved the optical properties of the PHB75/PCL25 films by increasing their transparency and accelerated the film disintegration in controlled soil conditions. In general, the blend with 3 wt% CNCs offers the best balanced properties in terms of mechanical, thermal, optical and wettability.This research was supported by the Ministry of Economy and Competitiveness MINECO through the gran number MAT2014-59242-C2-1-R. D. Garcia-Garcia wants to thank the Spanish Ministry of Education, Culture and Sports for the financial support through a FPU grant number FPU13/06011.Garcia-Garcia, D.; Balart, R.; Strömberg, E.; Moriana, R. (2018). Reinforcing capability of cellulose nanocrystals obtained from pine cones in a biodegradable poly(3-hydroxybutyrate)/poly(e-caprolactone) (PHB/PCL) thermoplastic blend. European Polymer Journal. 104:10-18. https://doi.org/10.1016/j.eurpolymj.2018.04.036S101810

    Development and characterization of bioactive alginate microcapsules with cedarwood essential oil

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    In this work, sodium alginate microcapsules containing cedarwood essential oil (CWO) for uses in anti-acne tonic were prepared by ionic gelification of alginate with calcium chloride (CaCl2) and subsequent addition of glutaraldehyde to improve the crosslinking degree. Alginate microcapsules with cedarwood essential oil were obtained in an encapsulator with a 600 μm nozzle using different alginate concentrations (1, 3 and 4% w/v) , and different compositions of the coagulation solution with CaCl2 concentrations of 0.1, 0.25 and 0.5 M, and addition of glutaraldehyde at two concentrations: 12.5% and 50% (0.1 g L−1 and 10 g L−1, respectively). The effect of alginate concentration was followed by viscosimetry and the influence of the CaCl2 concentration and presence of glutaraldehyde on the microcapsules' shape as well as the total content on encapsulated cedarwood essential oil were evaluated by means of stereoscopic magnifying glass, scanning electron microscopy (SEM) and UV vis spectrophotometry. Results show that proper shape formation is obtained for an alginate concentration of 3% w/v. With regard to the total encapsulated cedarwood oil, as the CaCl2 concentration in the gelifying-coagulating solution increases the efficiency of the encapsulated oil. Best results in terms of micro-bead shape and total amount of encapsulated oil were obtained for a CaCl2 concentration of 0.5 M without glutaraldehyde with a maximum encapsulation of 177.2 mg per gram of microcapsule.Ferrandiz, M.; Lopez, A.; Franco, E.; Garcia-Garcia, D.; Fenollar, D.; Balart, R. (2017). Development and characterization of bioactive alginate microcapsules with cedarwood essential oil. Flavour and Fragrance Journal. 32(3):184-190. doi:10.1002/ffj.3373S18419032

    Secondary Plastids of Euglenids and Chlorarachniophytes Function with a Mix of Genes of Red and Green Algal Ancestry

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    International audienceEndosymbiosis has been common all along eukaryotic evolution, providing opportunities for genomic and organellar innovation. Plastids are a prominent example. After the primary endosymbiosis of the cyanobacterial plastid ancestor, photosynthesis spread in many eukaryotic lineages via secondary endosymbioses involving red or green algal endosymbionts and diverse heterotrophic hosts. However, the number of secondary endosymbioses and how they occurred remain poorly understood. In particular, contrasting patterns of endosymbiotic gene transfer (EGT) have been detected and subjected to various interpretations. In this context, accurate detection of EGTs is essential to avoid wrong evolutionary conclusions. We have assembled a strictly selected set of markers that provides robust phylogenomic evidence suggesting that nuclear genes involved in the function and maintenance of green secondary plastids in chlorarachniophytes and euglenids have unexpected mixed red and green algal origins. This mixed ancestry contrasts with the clear red algal origin of most nuclear genes carrying similar functions in secondary algae with red plastids

    A Participação das ONGs nas Políticas Públicas: o Ponto de Vista de Gestores Federais

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    Produzido pelo Instituto de Pesquisa Econômica Aplicada (Ipea), o estudo A Participação das ONGs nas Políticas Públicas: o Ponto de Vista de Gestores Federais traz as percepções de gestores da alta burocracia federal quanto à decisão de implementar políticas públicas por meio da cooperação com organizações não governamentais (ONGs). A pesquisa sistematiza os motivos que animam a cooperação, as vantagens e desvantagens da implementação por meio de ONGs em face da burocracia pública e, por fim, os papéis relativos atribuídos ao Estado/burocracia e às ONGs nas políticas

    Leaf Categorization Methods for Plant Identification

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    In most of classic plant identification methods a dichotomous or multi-access key is used to compare characteristics of leaves. Some questions about if the analyzed leaves are lobed, unlobed, simple or compound need to be answered to identify plants successfully. However, very little attention has been paid to make an automatic distinction of leaves using such features. In this paper we first explore if incorporating prior knowledge about leaves (categorizing between lobed simple leaves, and the unlobed simple ones) has an effect on the performance of six classification methods. According to the results of experiments with more than 1,900 images of leaves from Flavia data set, we found that it is statically significant the relationship between such categorization and the improvement of the performances of the classifiers tested. Therefore, we propose two novel methods to automatically differentiate between lobed simple leaves, and the unlobed simple ones. The proposals are invariant to rotation, and achieve correct prediction rates greater than 98%

    Ultra‐Small Platinum Nanoparticles with High Catalytic Selectivity Synthesized by an Eco‐friendly Method Supported on Natural Hydroxyapatite

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    The biosynthesis of Pt-nanoparticles (Pt NPs) supported on bovine bone powder was conducted by an environmentally friendly method that consists on immersing bovine bone powder into a Pt4+ metal ion solution at room temperature, atmospheric pressure and subsequent reduction by Heterotheca inuloides. It is worth pointing out that a calcination process is not required for the synthesis of this catalyst by the method reported herein. The nanocomposite was characterized by transmission electron microscopy (TEM), which revealed uniformly dispersed platinum nanoparticles with quasi-spherical form and average particle size of 7.1 nm. The XPS studies exhibited the presence of 47.62% Pt° and 51.84% PtO. The catalyst activity was tested in the selective hydrogenation of 2-butyne-1,4-diol towards 2-butene-1,4-diol. The nanocomposite exhibits a reasonable catalytic performance with nearly 100% conversion of the alkyne and 96% selectivity towards 2-butene-1,4-diol.CONACY
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