Transport congestion events detection (TCED): towards decorrelating congestion detection from TCP

TCP (Transmission Control Protocol) uses a loss-based algorithm to estimate whether the network is congested or not. The main difficulty for this algorithm is to distinguish spurious from real network congestion events. Other research studies have proposed to enhance the reliability of this congestion estimation by modifying the internal TCP algorithm. In this paper, we propose an original congestion event algorithm implemented independently of the TCP source code. Basically, we propose a modular architecture to implement a congestion event detection algorithm to cope with the increasing complexity of the TCP code and we use it to understand why some spurious congestion events might not be detected in some complex cases. We show that our proposal is able to increase the reliability of TCP NewReno congestion detection algorithm that might help to the design of detection criterion independent of the TCP code. We find out that solutions based only on RTT (Round-Trip Time) estimation are not accurate enough to cover all existing cases. Furthermore, we evaluate our algorithm with and without network reordering where other inaccuracies, not previously identified, occur

Ret Finger Protein: An E3 Ubiquitin Ligase Juxtaposed to the XY Body in Meiosis

During prophase I of male meiosis, the sex chromosomes form a compact structure called XY body that associates with the nuclear membrane of pachytene spermatocytes. Ret Finger Protein is a transcriptional repressor, able to interact with both nuclear matrix-associated proteins and double-stranded DNA. We report the precise and unique localization of Ret Finger Protein in pachytene spermatocytes, in which Ret Finger Protein takes place of lamin B1, between the XY body and the inner nuclear membrane. This localization of Ret Finger Protein does not seem to be associated with O-glycosylation or sumoylation. In addition, we demonstrate that Ret Finger Protein contains an E3 ubiquitin ligase activity. These observations lead to an attractive hypothesis in which Ret Finger Protein would be involved in the positioning and the attachment of XY body to the nuclear lamina of pachytene spermatocytes

Tunable Kondo effect in double quantum dots coupled to ferromagnetic contacts

We investigate the effects induced by spin polarization in the contacts attached to a serial double quantum dot. The polarization generates effective magnetic fields and suppresses the Kondo effect in each dot. The super-exchange interaction ($J_{\mathrm{AFM}}$), tuned by the inter-dot tunnelling rate $t$, can be used to compensate the effective fields and restore the Kondo resonance when the contact polarizations are aligned. As a consequence, the direction of the spin conductance can be controlled and even reversed using electrostatic gates alone. Furthermore, we study the associated two-impurity Kondo model and show that a ferromagnetic exchange coupling ($J_{\mathrm{FM}}$) leads to an effective spin-1 exchange-anisotropic Kondo model which exhibits a quantum phase transition in the presence of partially polarized contacts.Comment: 5 pages, 4 figure

The 3B/X3 solar flare of 27 February 1992

Analizamos la evolución de la región activa (AR) NOAA 7070 y la relacionamos con una fulguración 3B/X3, ocurrida el 27 de febrero de 1992. Las observaciones en rayos X blandos fueron obtenidas por el SXT (Soft X-ray Telescope) a bordo del satélite Yohkoh y las imágenes en Hα provienen del Observatorio de Udaipur (India). La ubicación de los núcleos y bandas de la fulguración y la forma de los arcos en rayos X se comparan con el modelo del campo magnético de la AR. Tanto las observaciones como el modelo muestran que los arcos coronales presentan alto “shear” antes de la fulguración y que la configuración se relaja luego de la liberación de la energía. Calculamos la energía magnética libre utilizando el teorema del virial, hallando un límite inferior de 2X1032 erg. Este valor concuerda con los valores típicos de energía liberada por estos fenómenos.Active region NOAA 7070 was related to a 3B/X3 solar flare that occurred on February 27, 1992. The soft X-ray flare observations were obtained by the SXT (Soft X-ray Telescope) on board the Yohkoh satellite, and those in Hα from the Udaipur Observatory. The location of the Hα kernels and ribbons, and the shape of soft X-ray loops are compared with the magnetic field model of the AR. Both, observations and model, suggest that the coronal loops are highly sheared before the flare and that the configuration relaxes after energy release. We compute the magnetic free energy at 2×1032 erg; this value is typical for the energy released by solar flares.Fil: Lopez Fuentes, Marcelo Claudio. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mandrini, Cristina Hemilse. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Rovira, Marta Graciela. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Démoulin, Pascal. Centre National de la Recherche Scientifique. Observatoire de Paris; Franci

Subtypes of NanS-p sialate O-acetylesterase encoded by Stx2a bacteriophages

Shiga toxin (Stx)-producing Escherichia coli strains are foodborne pathogens that cancause severe human diseases, such as haemorrhagic colitis and haemolytic-uraemic syndrome. Stxsare encoded by bacteriophages (Stx phages) which show remarkable variations in genomecomposition and harbour several genes of unknown function. Recently, a gene encoding a sialateO-acetylesterase (NanS-p) was identified in some relevant Stx2a phages and it was suggested that itcould provide advantages for bacterial growth in the gut. The aim of this study was to analyse thepresence and sequence of nanS-p genes in available Stx2a phage genomes. A total of 59 DNAsequences of Stx2a phages were extracted from the NCBI GenBank database with the BLASTprogram using the stx2a sequence from phage 933W as query sequence, either as complete phagegenomes (45) or from bacterial genomes by subsequent analysis with PHASTER web server (14).Comparative analysis revealed that nanS-p was located downsteam stx2a in all genomes. Twentydifferent amino acid sequences of NanS-p were identified. Specifically, catalytic esterase domainsshowed only 11 possible sequences, with differences mainly observed in nine amino acid positions.Sequences corresponding to the N-terminal domain (DUF1737) showed three possible sequences,two of them closely related, while C-terminal domain was highly variable giving place to fourgroups with structural differences. Since sialate O-acetylesterase activity has been determined fromparticular Stx2a phages, new studies are necessary to evaluate if the NanS-p subtypes identified inthe present study also differ in their biological activity.Fil: Pascal, Stefanía Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Lorenzo Lopez, Juan Ramiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Lucchesi, Paula Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Krüger, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina1st International Electronic Conference on MicrobiologySuizaMDP

DISCUSSION ON THE COMPOSITION AND TRANSPORT COEFFICIENTS CALCULATION MADE IN PLASMA OUT OF EQUILIBRIUM

International audienceIn this paper, the composition calculation in plasma out of thermal equilibrium is discussed and we test the viscosity formulations of Wilke, Gupta et al, Chapman Enskog and Sutherland in air plasma out of thermal equilibrium. Finally we applied the formulations to Fire II reentry

Idm@ti Network: an innovatiove proposal for improving teaching and learning in Spanish universities

IdM@ti network members concurred in the diagnosis of the difficulties and opportunities arising from Bologna process implementation and teaching methodologies improvement in Materials Science and Engineering (MSE) teaching. This network has been created with the aim of improving efficiency of underway and future collaborations.The main objectives are related to MSE resources sharing (course programs, exercises, lab scripts, projects, PBL and case studies, etc.). The network will allow classifying those educational resources already individually implemented by each University, monitoring their statewide and promote the creation of new resources. In order to promote discussion and sharing of experiences, achievements and challenges, a workshop is annually organized, arose from the convenience of joining forces on the axes of innovation and improving the quality of teaching in MSE field