484 research outputs found

    Discrete breathers in dc biased Josephson-junction arrays

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    We propose a method to excite and detect a rotor localized mode (rotobreather) in a Josephson-junction array biased by dc currents. In our numerical studies of the dynamics we have used experimentally realizable parameters and included self-inductances. We have uncovered two families of rotobreathers. Both types are stable under thermal fluctuations and exist for a broad range of array parameters and sizes including arrays as small as a single plaquette. We suggest a single Josephson-junction plaquette as an ideal system to experimentally investigate these solutions.Comment: 5 pages, 5 figure, to appear June 1, 1999 in PR

    Increased cerebrospinal fluid levels of cytokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1β (MIP-1β) in patients with amyotrophic lateral sclerosis

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    Introduction: Neuroinflammation has recently been described in amyotrophic lateral sclerosis (ALS). However, the precise role of such proinflammatory cytokines as monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1� (MIP-1�) in ALS has not yet been determined. In this study, we determined cerebrospinal fluid (CSF) MCP-1 and MIP-1� levels and assessed their association with the duration and severity of ALS. Methods: Concentrations of MCP-1 and MIP-1� were determined in the CSF of 77 patients diagnosed with ALS and 13 controls. Cytokine levels were analysed in relation to ALS duration ( 12 months) and severity ( 30 points on the ALS Functional Rating Scale administered at hospital admission). Results: Higher CSF MIP-1� (10.68 pg/mL vs 4.69 pg/mL, P < .0001) and MCP-1 (234.89 pg/mL vs 160.95 pg/mL, P = .011) levels were found in the 77 patients with ALS compared to controls. There were no differences in levels of either cytokine in relation to disease duration or severity. However, we did observe a significant positive correlation between MIP-1� and MCP-1 in patients with ALS. Conclusions: The increase in MIP-1� and MCP-1 levels suggests that these cytokines may havea synergistic effect on ALS pathogenesis. However, in our cohort, no association was found witheither the duration or the clinical severity of the disease

    New silica based adsorbent material from rice straw and its in-flow application to nitrate reduction in waters: Process sustainability and scale-up possibilities

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    [EN] This paper shows a particular example to move to a sustainable circular economical process from valorization of rice straw ashes by developing a green synthesis for obtaining a useful sub-product. This strategy can palliate negative effects of the agriculture waste practices on the environment and also the obtained silica reduced nitrate content in waters. It is demonstrated that the silica synthesis developed at lab was scalable more than a hundred times with good results. Adsorption studies of nitrate in standards and real well waters at lab scale and scaling-up provided similar results. Adsorption values near to 15 mg/g for nitrate standards and 8.5 mg/g for well water were obtained until achieving the initial nitrate concentration. Experimental breakthrough curves fitted to Thomas model, which gave similar results for adsorption capacities. The adsorption capacity was checked with that obtained by a commercial resin, providing improved results. The method at large scale was compared with industrial traditional methods and green adsorbents.The authors are grateful to EU (EASME LIFE and CIP ECO-Innovation) LIBERNITRATE. LIFE 16 ENV/ES/000419; EU FEDER and the Gobierno de Espana MCIU-AEI (CTQ2017-90082-P) and the Generalitat Valenciana (PROMETEO 2020/078) and EU FEDER-Generalitat Valenciana (ID-FEDER/2018/049) for the financial support received. H. R. Robles-Jimarez expresses his grateful to EU-LIBERNITRATE. L. Sanjuan-Navarro expresses his gratitude for the FPU-grant (MCIU-AEI) .Robles-Jimarez, H.; Sanjuan-Navarro, L.; Jornet-Martínez, N.; Primaz, C.; Teruel-Juanes, R.; Molins-Legua, C.; Ribes-Greus, A.... (2022). New silica based adsorbent material from rice straw and its in-flow application to nitrate reduction in waters: Process sustainability and scale-up possibilities. Science of The Total Environment. 805:1-12. https://doi.org/10.1016/j.scitotenv.2021.15031711280

    High prevalence of secondary resistance mutations in Venezuelan HIV-1 isolates.

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    The genetic variability was studied in HIV-1 from Venezuelan patients with and without treatment, in order to evaluate the presence of polymorphisms and drug resistance mutations. Proviral DNA from peripheral blood mononuclear cells or viral RNA from plasma was extracted from the blood of 30 patients. Two regions from the polymerase gene, protease (Pr) and reverse transcriptase (RT) and one genomic fragment from the envelope (Env) gene were amplified and sequenced. All HIV-1 samples analyzed were classified as subtype B, without evidence of recombination. Although no primary protease mutations were detected, a high frequency of secondary mutations (86%, 19/22), associated to restoration of viral replicative fitness, was observed in strains circulating both in treated and non-treated patients. Resistance mutations to nucleoside RT inhibitors (NRTI) and non-nucleoside RT inhibitors (NNRTI) were detected in 35% (6/17) and 12% (2/17) of the viruses circulating in treated patients, respectively. Resistance mutations were also present in the virus infecting one antiretroviral naive individual (7.7%), suggesting that local screening for resistant mutation in naive patient might be important to minimize therapy failure. Future studies are warranted to assess the role of secondary mutation in the success of viral infection

    Neutral Pions and Eta Mesons as Probes of the Hadronic Fireball in Nucleus-Nucleus Collisions around 1A GeV

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    Chemical and thermal freeze-out of the hadronic fireball formed in symmetric collisions of light, intermediate-mass, and heavy nuclei at beam energies between 0.8A GeV and 2.0A GeV are discussed in terms of an equilibrated, isospin-symmetric ideal hadron gas with grand-canonical baryon-number conservation. For each collision system the baryochemical potential mu_B and the chemical freeze-out temperature T_c are deduced from the inclusive neutral pion and eta yields which are augmented by interpolated data on deuteron production. With increasing beam energy mu_B drops from 800 MeV to 650 MeV, while T_c rises from 55 MeV to 90 MeV. For given beam energy mu_B grows with system size, whereas T_c remains constant. The centrality dependence of the freeze-out parameters is weak as exemplified by the system Au+Au at 0.8A GeV. For the highest beam energies the fraction of nucleons excited to resonance states reaches freeze-out values of nearly 15 %, suggesting resonance densities close to normal nuclear density at maximum compression. In contrast to the particle yields, which convey the status at chemical freeze-out, the shapes of the related transverse-mass spectra do reflect thermal freeze-out. The observed thermal freeze-out temperatures T_th are equal to or slightly lower than T_c, indicative of nearly simultaneous chemical and thermal freeze-out.Comment: 42 pages, 12 figure

    Incremento de las citoquinas proteína quimiotáctica de monocitos-1 (MCP-1) y proteína inflamatoria macrofágica-1β (MIP-1β) en líquido cefalorraquídeo de pacientes con esclerosis lateral amiotrófica

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    Introducción: En la esclerosis lateral amiotrófica (ELA) se ha descrito recientemente la presencia de neuroinflamación. Sin embargo, no se ha definido el rol de citoquinas proinflamatrorias como la proteína quimiotáctica de monocitos-1 (MCP-1) y la proteína inflamatoria macrofágica-1� (MIP-1�) en ELA. En este estudio evaluamos niveles de MCP-1 y MIP-1� en líquido cefalorraquídeo (LCR), analizando su participación en la duración y gravedad de la ELA. Métodos: En 77 pacientes con ELA definida y 13 sujetos controles, se comparó el nivel de citoquinas MCP-1 y MIP-1� en LCR. Se analizaron estos niveles con relación a la duración de la ELA ( 12 meses) y a la gravedad de esta determinada mediante el puntaje obtenido al ingreso en la escala funcional estratificada de la ELA ( 30 puntos). Resultados: En los 77 pacientes con ELA, se encontraron aumentados los niveles de MIP-1� (4,69 pg/ml vs. 10,68 pg/ml, p < 0,0001) y MCP-1 (160,95 pg/ml vs. 234,89 pg/ml, p = 0,011) en comparación con sujetos controles. No se observó diferencia de los niveles de estas citoquinas con la duración o la gravedad de la enfermedad. Sin embargo, observamos una correlación positiva significativa entre MIP-1� y MCP-1 en pacientes con ELA. Conclusiones: El aumento de MIP-1� y MCP-1 sugiere que estas citoquinas parecen tener unefecto sinérgico en la patogénesis de la ELA. Sin embargo, en nuestra cohorte no se asociaroncon la duración o la gravedad de la ELA

    Perceptions and attitudes to sustainable roundworm control by European sheep farmers

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    Trabajo presentado al: 28th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP). Dublín. 19-22 julio. Virtual meeting

    Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

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    Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic

    The exposure of the hybrid detector of the Pierre Auger Observatory

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    The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The "hybrid" detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data collected during operations, such as the status of the fluorescence detector, background light and atmospheric conditions, that are used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic
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