287 research outputs found

    A Simple and Robust Dissemination Protocol for VANETs

    Get PDF
    Several promising applications for Vehicular Ad-hoc Networks (VANETs) exist. For most of these applications, the communication among vehicles is envisioned to be based on the broadcasting of messages. This is due to the inherent highly mobile environment and importance of these messages to vehicles nearby. To deal with broadcast communication, dissemination protocols must be defined in such a way as to (i) prevent the so-called broadcast storm problem in dense networks and (ii) deal with disconnected networks in sparse topologies. In this paper, we present a Simple and Robust Dissemination (SRD) protocol that deals with these requirements in both sparse and dense networks. Its novelty lies in its simplicity and robustness. Simplicity is achieved by considering only two states (cluster tail and non- tail) for a vehicle. Robustness is achieved by assigning message delivery responsibility to multiple vehicles in sparse networks. Our simulation results show that SRD achieves high delivery ratio and low end-to-end delay under diverse traffic conditions

    Evaluation of the AR4 CMIP3 and the AR5 CMIP5 model and projections for precipitation in northeast Brazil

    Get PDF
    This article compares the sensitivity of IPCC CMIP3-AR4 and CMIP5-AR5 models used on the latest reports from the Intergovernmental Panel on Climate Change (IPCC) in representing the annual average variations (austral summer and autumn) on three regions in Northeastern Brazil (NNEB) for the periods 1979–2000 using the CMAP (Climatology Merged Analysis of Precipitation) data as reference. The three areas of NNEB chosen for this analysis were the semiarid, eastern, and southern regions. The EOF analysis was performed to investigate how the coupled models resolve the temporal variability of the spatial modes in the Tropical Atlantic Sea Surface Temperature (SST), which drives the interannual variations of the rainfall in the Northeastern Brazil. CMIP3-AR4 and CMIP5-AR5 models presented a good representation of the annual cycle of precipitation. Results from correlation and mean absolute error analysis indicate that both CMIP3 and CMIP5 models produce large errors and barely capture the interannual rainfall variance during austral summer and autumn in Northeast Brazil, this features is closely related to the poor representation of the modes of SST variability in the Tropical Atlantic Ocean. For the summer and autumn rainfall projections (2040–2070) in the semiarid region, there was no convergence between the CMIP3 and CMIP5 models. During the summer and autumn in the eastern sector, both the CMIP3 and CMIP5 models projected rainfall above the mean for the 2040–2070 period

    O pessegueiro no sistema de pomar compacto: VII. comportamento de novas seleções IAC sob poda drástica bienal

    Get PDF
    Five new peach and nectarin selections were grown under the meadow orchard system, with bienal drastic pruning, at 4m x 0.5m and 4m x lm spacings. The experimental area was located in Monte Alegre do Sul, (22°41'S; 46°43'W and 40 hours below 7°C) State of São Paulo, Brazil. Results obtained during the six years of experiments clearly indicate that the 'Aurora-2' and IAC 282-24 peach selections were the best, with an average yield above 19 ton per hectare. For 4m x 0.5m spacing, with a density of 5000 plants per hectare, the productivity increased about 12%, however decreasing the weight of the final product. The best average weights of the fruits, above of l00g, were obtained by the IAC 6782-83 and IAC 282-24 selections.Pesquisou-se durante seis anos o comportamento reprodutivo de cinco novas seleções de pêssego e nectarina em Monte Alegre do Sul (22°41'S; 46°43'W e 40 HF-7). Os pessegueiros e nectarineiras cultivados nos espaçamentos de 4 x 0,5m e 4 x Im, equivalentes a 5000 e 2500 plantas/ha, respectivamente, foram podados drasticamente, a cada dois anos, após a colheita. Em ambos espaçamentos,'Aurora-2* e IAC 282-24 apresentaram as melhores produções acima de 19 toneladas/ha. Verificou-se nos ciclos subseqüentes a cada poda da copa, tendência de menor produção das plantas, principalmente em material de ciclo mediano. No segundo ano após a poda drástica, os pessegueiros e nectarineiras produziram normalmente. No espaçamento de 4 x 0,5m, as plantas apresentaram acréscimo médio de 12% na produção, em relação a 4 x lm, diminuindo porém, o peso do produto final. Os maiores frutos com peso médio acima de l00g foram produzidos pelas seleções IAC 6782-83 e IAC 282-24

    Criticality in confined ionic fluids

    Full text link
    A theory of a confined two dimensional electrolyte is presented. The positive and negative ions, interacting by a 1/r1/r potential, are constrained to move on an interface separating two solvents with dielectric constants ϵ1\epsilon_1 and ϵ2\epsilon_2. It is shown that the Debye-H\"uckel type of theory predicts that the this 2d Coulomb fluid should undergo a phase separation into a coexisting liquid (high density) and gas (low density) phases. We argue, however, that the formation of polymer-like chains of alternating positive and negative ions can prevent this phase transition from taking place.Comment: RevTex, no figures, in press Phys. Rev.

    Co-activation of NF-κB and MYC renders cancer cells addicted to IL6 for survival and phenotypic stability

    Get PDF
    NF-κB and MYC are found co-deregulated in human B and plasma-cell cancers. In physiology, NF-κB is necessary for terminal B-to-plasma cell differentiation, whereas MYC repression is required. It is thus unclear if NF-κB/MYC co-deregulation is developmentally compatible in carcinogenesis and/or impacts cancer cell differentiation state, possibly uncovering unique sensitivities. Using a mouse system to trace cell lineage and oncogene activation we found that NF-κB/MYC co-deregulation originated cancers with a plasmablast-like phenotype, alike human plasmablastic-lymphoma and was linked to t(8;14)[MYC-IGH] multiple myeloma. Notably, in contrast to NF-κB or MYC activation alone, co-deregulation rendered cells addicted to IL6 for survival and phenotypic stability. We propose that conflicting oncogene-driven differentiation pressures can be accommodated at a cost in poorly-differentiated cancers. SIGNIFICANCE: Our studies improve the understanding of cancer pathogenesis by demonstrating that co-deregulation of NF-κB and MYC synergize in forming a cancer with a poorly-differentiated state. The cancers in the mouse system share features with human Plasmablastic lymphoma that has a dismal prognosis and no standard of care, and with t(8;14)[MYC-IGH] Multiple myeloma, which is in overall resistant to standard therapy. Notably, we found that NF-κB and MYC co-deregulation uniquely render cells sensitive to IL6 deprivation, providing a road-map for patient selection. Because of the similarity of the cancers arising in the compound mutant mouse model with that of human Plasmablastic lymphoma and t(8;14)[MYC-IGH] Multiple myeloma, this model could serve in preclinical testing to investigate novel therapies for these hard-to-treat diseases

    Genome sequence and effectorome of Moniliophthora perniciosa and Moniliophthora roreri subpopulations

    Get PDF
    Background: The hemibiotrophic pathogens Moniliophthora perniciosa (witches' broom disease) and Moniliophthora roreri (frosty pod rot disease) are among the most important pathogens of cacao. Moniliophthora perniciosa has a broad host range and infects a variety of meristematic tissues in cacao plants, whereas M. roreri infects only pods of Theobroma and Herrania genera. Comparative pathogenomics of these fungi is essential to understand Moniliophthora infection strategies, therefore the detection and in silico functional characterization of effector candidates are important steps to gain insight on their pathogenicity. Results: Candidate secreted effector proteins repertoire were predicted using the genomes of five representative isolates of M. perniciosa subpopulations (three from cacao and two from solanaceous hosts), and one representative isolate of M. roreri from Peru. Many putative effectors candidates were identified in M. perniciosa: 157 and 134 in cacao isolates from Bahia, Brazil; 109 in cacao isolate from Ecuador, 92 and 80 in wild solanaceous isolates from Minas Gerais (Lobeira) and Bahia (Caiçara), Brazil; respectively. Moniliophthora roreri showed the highest number of effector candidates, a total of 243. A set of eight core effectors were shared among all Moniliophthora isolates, while others were shared either between the wild solanaceous isolates or among cacao isolates. Mostly, candidate effectors of M. perniciosa were shared among the isolates, whereas in M. roreri nearly 50% were exclusive to the specie. In addition, a large number of cell wall-degrading enzymes characteristic of hemibiotrophic fungi were found. From these, we highlighted the proteins involved in cell wall modification, an enzymatic arsenal that allows the plant pathogens to inhabit environments with oxidative stress, which promotes degradation of plant compounds and facilitates infection. Conclusions: The present work reports six genomes and provides a database of the putative effectorome of Moniliophthora, a first step towards the understanding of the functional basis of fungal pathogenicity. © 2018 The Author(s).This work was done in the frame of the International Consortium in Advanced Biology (CIBA; https://www.ciba-network.org). The authors thank the Molecular Plant Pathology Laboratory and the Plant Pathology Laboratory at INIAP personnel for their assistance in obtaining the DNAs, Dr Carmen Suarez Capello for her kind assistance in Ecuador, and the Núcleo de Biologia Computacional e Gestão de Informações Biotecnológicas - UESC (NBCGIB), and Copenhague University for providing bioinformatics facility. Data sets were processed in sagarana HPC cluster, CPAD-ICB-UFMG. The authors would also like to thank Dr. Claudia Fortes Ferreira (Embrapa CNPMF, Brazil) and Dr. Raul Renné Valle (CEPLAC/CEPEC, Brazil) for English language revision. We are also grateful to Ivanna Michelle Meraz Pérez for helping translating an early version of this manuscript and to the anonymous reviewers who provided helpful comments to our work. KPG, FM and CPP were supported by research fellowship Pq-1 from CNPq. National Council for Scientific Development (CNPq) n° 311759/2014–9. CSB acknowledges FAPESB (Foundation for Research Support of the State of Bahia) for supporting her with a research assistantship during her Master’s Programme

    The Fluorescence Detector of the Pierre Auger Observatory

    Get PDF
    The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section

    Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

    Get PDF
    Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius AA. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio

    Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

    Get PDF
    Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{6×10196\times 10^{19}eV}. The anisotropy was measured by the fraction of arrival directions that are less than 3.13.1^\circ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron 12th12^{\rm th} catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (386+7)(38^{+7}_{-6})%, compared with 2121% expected for isotropic cosmic rays. This is down from the early estimate of (6913+11)(69^{+11}_{-13})%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201
    corecore