1,711 research outputs found

    Operational and Performance Issues of a CBQ router

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    The use of scheduling mechanisms like Class Based Queueing (CBQ) is expected to play a key role in next generation multiservice IP networks. In this paper we attempt an experimental evaluation of ALTQ/CBQ demonstrating its sensitivity to a wide range of parameters and link layer driver design issues. We pay attention to several CBQ internal parameters that affect performance drastically and particularly to “borrowing”, a key feature for flexible and efficient link sharing. We are also investigating cases where the link sharing rules are violated, explaining and correcting these effects wheneverpossible. Finally we evaluateCBQ performance and make suggestions for effective deployment in real networks.

    NFV service dynamicity with a DevOps approach : demonstrating zero-touch deployment & operations

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    Next generation network services will be realized by NFV-based microservices to enable greater dynamics in deployment and operations. Here, we present a demonstrator that realizes this concept using the NFV platform built in the EU FP7 project UNIFY. Using the example of an Elastic Router service, we show automated deployment and configuration of service components as well as corresponding monitoring components facilitating automated scaling of the entire service. We also demonstrate automatic execution of troubleshooting and debugging actions. Operations of the service are inspired by DevOps principles, enabling quick detection of operational conditions and fast corrective actions. This demo conveys essential insights on how the life-cycle of an NFV-based network service may be realized in future NFV platforms

    Hydrodynamic theory for granular gases

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    A granular gas subjected to a permanent injection of energy is described by means of hydrodynamic equations derived from a moment expansion method. The method uses as reference function not a Maxwellian distribution fMf_{\sf M} but a distribution f0=ΦfMf_0 = \Phi f_{\sf M}, such that Φ\Phi adds a fourth cumulant κ\kappa to the velocity distribution. The formalism is applied to a stationary conductive case showing that the theory fits extraordinarily well the results coming from our molecular dynamic simulations once we determine κ\kappa as a function of the inelasticity of the particle-particle collisions. The shape of κ\kappa is independent of the size NN of the system.Comment: 10 pages, 9 figures, more about our research in http://www.cec.uchile.cl/cinetica

    2n Gamete formation in the genus Brachiaria (Poaceae: Paniceae).

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    Microsporogenesis of several Brachiaria species of the Brazilian collection at Embrapa Beef Cattle has been analyzed in detail. This paper reports abnormal cytokinesis in three accessions of three different species (Brachiaria humidicola, 2n = 4x = 36, Brachiaria decumbens, 2n = 4x = 36, and Brachiaria dura, 2n = 6x = 54). Chromosomes paired in bi-, tri-, and quadrivalents in these accessions, whereas chromosome segregation at meiosis I was characterized by exclusion of laggards as micronuclei. In a high number of meiocytes, the first sign of cytokinesis appeared only in metaphase II and did not divide the meiocyte into a dyad. Total absence of cytokinesis was also detected among meiocytes in the second division. Since in both cases the two metaphase plates were very close, they favored the rejoining of chromosome sets after anaphase II and formed a restitutional nucleus in telophase II. Second cytokinesis occurred after telophase II in most meiocytes. Monads, dyads, and triads with n or 2n nuclei were observed among meiotic products. The 2n gametes observed correspond to the first division restitution (FDR). The number of affected cells in each accession was variable, but the number of microspores with restitutional nucleus, including those scored in tetrads and the released ones, did not exceed 9%. Although polyploidy is common in the genus Brachiaria, its origin is still unclear. Current results suggest that 2n gametes may have contributed to the evolutionary history of the genus.CNPGC

    Extended hydrodynamics from Enskog's equation for a two-dimensional system general formalism

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    Balance equations are derived from Enskog's kinetic equation for a two-dimensional system of hard disks using Grad's moment expansion method. This set of equations constitute an extended hydrodynamics for moderately dense bi-dimensional fluids. The set of independent hydrodynamic fields in the present formulations are: density, velocity, temperature {\em and also}--following Grad's original idea--the symmetric and traceless pressure tensor pijp_{ij} and the heat flux vector qk\mathbf q^{k}. An approximation scheme similar in spirit to one made by Grad in his original work is made. Once the hydrodynamics is derived it is used to discuss the nature of a simple one-dimensional heat conduction problem. It is shown that, not too far from equilibrium, the nonequilibrium pressure in this case only depends on the density, temperature and heat flux vector.Comment: :9 pages, 1 figure, This will appear in J. Stat. Phys. with minor corrections and corresponds to Ref[9] of cond-mat/050710

    Efecto del methoprene sobre <i>Musca domestica</i>: ensayos de laboratorio

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    To determine methoprene's (MTP) effect on fly Musca domestica emergence were performed laboratory bioassays using a technical formulation identified as MK55, in the form of a granulated insoluble in water. Concentrations of 1.625, 4.5 and 10 ppm of MTP were mixed directly with poultry manure, and larvae I of Musca domestica were fed (test 1). The same MTP concentrations (1.625, 4.5 and 10 ppm) were added to chicken feed and then, the manure produced by the chicken was used as feed to M. domestica larvae I ( test 2); each test involved five assays and one untreated check, in both larvae II and III were grown by feeding manure. Pupae were controlled until fly adults emergence. The percentage of fly growth in each assay decreased in relation to the increase of MTP concentrations and 77.1% of efficacy was shown when 10 ppm was used directly mixed with manure. And 83.7% of efficacy was demonstrated when used as a feed additive. However, a high variability of results was observed in low concentrations. MTP should be used at the highest doses and integrated with other methods to control M. domestica fly in poultry farms.Con el propósito de evaluar el efecto del methoprene (MTP) sobre la emergencia de adultos de Musca domestica, se realizaron ensayos bajo condiciones de laboratorio con una formulación granulada insoluble en agua, identificada como MK55. Concentraciones de 1.625, 4.5 y 10 ppm de MTP fueron mezcladas directamente con estiércol de gallina y ofrecidas como alimento a larvas I de M. domestica (test 1). Las mismas concentraciones de MTP (1.625, 4.5 y 10 ppm) fueron adicionadas al alimento balanceado para gallinas y luego la materia fecal producida por esos animales se usó como fuente alimenticia de larvas I de M. domestica (test 2); cada test involucró cinco ensayos y un control sin tratar, en ambos, larvas II y III se desarrollaron alimentándose con estiércol de gallina. Las pupas fueron controladas hasta la emergencia de los adultos. El porcentaje de moscas nacidas en cada ensayo disminuyó en relación al aumento de la concentración de MTP y se demostró una eficacia del 77,1% y del 83,7% cuando se utilizó 10 ppm mezclado directamente en las heces, y como aditivo en el alimento, respectivamente. No obstante, en bajas concentraciones se observó gran variabilidad en los resultados. El methoprene debería ser usado en concentraciones elevadas y en combinación con otros métodos para un control óptimo de adultos de M. domestica en explotaciones avícolas

    HLA-G expression and role in advanced-stage classical Hodgkin lymphoma

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    Non-classical human leucocyte antigen (HLA)-G class I molecules have an important role in tumor immune escape mechanisms. We investigated HLA-G expression in lymphonode biopsies taken from 8 controls and 20 patients with advanced-stage classical Hodgkin lymphoma (cHL), in relationship to clinical outcomes and the HLA-G 14-basepair (14-bp) deletion-insertion (del-ins) polymorphism. Lymphnode tissue sections were stained using a specific murine monoclonal HLA-G antibody. HLA-G protein expression was higher in cHL patients than controls. In the group of PET-2 positive (positron emission tomography carried out after 2 cycles of standard chemotherapy) patients with a 2-year progression-free survival rate (PFS) of 40%, we observed high HLA-G protein expression within the tumor microenvironment with low expression on Hodgkin and Reed-Sternberg (HRS) cells. Conversely, PET-2 negative patients with a PFS of 86% had higher HLA-G protein expression levels on HRS cells compared to the microenvironment. Lower expression on HRS cells was significantly associated with the HLA-G 14-bp ins/ins genotype. These preliminary data suggest that the immunohistochemical pattern of HLA-G protein expression may represent a useful tool for a tailored therapy in patients with cHL, based on the modulation of HLA-G expression in relation to achievement of negative PET-
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