1,958 research outputs found

    The innermost regions of the jet in NRAO 150. Wobbling or internal rotation?

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    NRAO 150 is a very bright millimeter to radio quasar at redshift zz=1.52 for which ultra-high-resolution VLBI monitoring has revealed a counter-clockwise jet-position-angle wobbling at an angular speed 11\sim11^{\circ}/yr in the innermost regions of the jet. In this paper we present new total and linearly polarized VLBA images at 43 GHz extending previous studies to cover the evolution of the jet in NRAO 150 between 2006 and early 2009. We propose a new scenario to explain the counter-clockwise rotation of the jet position angle based on a helical motion of the components in a jet viewed faced-on. This alternative scenario is compatible with the interpretation suggested in previous works once the indetermination of the absolute position of the self-calibrated VLBI images is taken into account. Fitting of the jet components motion to a simple internal rotation kinematical model shows that this scenario is a likely alternative explanation for the behavior of the innermost regions in the jet of NRAO 150.Comment: 5 pages, 4 figures, Presented in 'The Innermost Regions of Relativistic Jets and Their Magnetic Fields' conference. Granada, Spain, 201

    MAPCAT: Monitoring AGN with Polarimetry at the Calar Alto Telescopes

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    We introduce MAPCAT, a long-term observing program for "Monitoring of AGN with Polarimetry at the Calar Alto Telescopes". Multi-spectral-range studies are critical to understand some of the most relevant current problems of high energy astrophysics of blazars such as their high energy emission mechanisms and the location of their gamma-ray emission region through event associations across the spectrum. Adding multi-spectral-range polarimetry allows for even more reliable identification of polarized flares across the spectrum in these kind of objects, as well as for more accurate modeling of their magnetic field. As part of a major international effort to study the long term multi-spectral range polarimetric behavior of blazars, MAPCAT uses -since mid 2007- CAFOS on the 2.2m Telescope at the Calar Alto Observatory (Almeria, Spain) to obtain monthly optical (R-band) photo-polarimetric measurements of a sample of 34 of the brightest gamma-ray, optical, and radio-millimeter blazars accessible from the northern hemisphere.Comment: To be published in the proceedings of High Energy Phenomena in Relativistic Outflows III (HEPRO III, IJMPCS). 4 page

    Standardization of molecular monitoring for chronic myeloid leukemia in Latin America using locally produced secondary cellular calibrators

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    Residual disease in chronic myeloid leukemia (CML) patients undergoing therapy with tyrosine kinase inhibitors (TKIs) is measured by assessing the quantity of transcripts of the BCR-ABL1 fusion gene in peripheral white blood cells. This analysis is based on reverse-transcription quantitative PCR (RT–qPCR) technology; however, the wide array of methods used worldwide has led to large variation in quantitative BCR-ABL1 measurements, which hamper inter-laboratory comparative studiesFil: Ruiz, María Sol. Fundación Cáncer. Centro de Investigaciones Oncológicas; ArgentinaFil: Medina, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Tapia, I.. Fundación Cáncer. Centro de Investigaciones Oncológicas; ArgentinaFil: Mordoh, Jose. Fundación Cáncer. Centro de Investigaciones Oncológicas; ArgentinaFil: Cross, N. C. P.. Universidad de Southampton Uk; Reino UnidoFil: Larripa, Irene Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Bianchini, Michele. Fundación Cáncer. Centro de Investigaciones Oncológicas; Argentin

    Stability Properties of Strongly Magnetized Spine Sheath Relativistic Jets

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    The linearized relativistic magnetohydrodynamic (RMHD) equations describing a uniform axially magnetized cylindrical relativistic jet spine embedded in a uniform axially magnetized relativistically moving sheath are derived. The displacement current is retained in the equations so that effects associated with Alfven wave propagation near light speed can be studied. A dispersion relation for the normal modes is obtained. Analytical solutions for the normal modes in the low and high frequency limits are found and a general stability condition is determined. A trans-Alfvenic and even a super-Alfvenic relativistic jet spine can be stable to velocity shear driven Kelvin-Helmholtz modes. The resonance condition for maximum growth of the normal modes is obtained in the kinetically and magnetically dominated regimes. Numerical solution of the dispersion relation verifies the analytical solutions and is used to study the regime of high sound and Alfven speeds.Comment: 42 pages includes 7 figures, to appear in Ap

    Inverting Ray-Knight identity

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    We provide a short proof of the Ray-Knight second generalized Theorem, using a martingale which can be seen (on the positive quadrant) as the Radon-Nikodym derivative of the reversed vertex-reinforced jump process measure with respect to the Markov jump process with the same conductances. Next we show that a variant of this process provides an inversion of that Ray-Knight identity. We give a similar result for the Ray-Knight first generalized Theorem.Comment: 18 page

    3D Relativistic Magnetohydrodynamic Simulations of Magnetized Spine-Sheath Relativistic Jets

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    Numerical simulations of weakly magnetized and strongly magnetized relativistic jets embedded in a weakly magnetized and strongly magnetized stationary or weakly relativistic (v = c/2) sheath have been performed. A magnetic field parallel to the flow is used in these simulations performed by the new GRMHD numerical code RAISHIN used in its RMHD configuration. In the numerical simulations the Lorentz factor γ=2.5\gamma = 2.5 jet is precessed to break the initial equilibrium configuration. In the simulations sound speeds are c/3\lesssim c/\sqrt 3 in the weakly magnetized simulations and 0.3c\lesssim 0.3c in the strongly magnetized simulations. The Alfven wave speed is 0.07c\lesssim 0.07c in the weakly magnetized simulations and 0.56c\lesssim 0.56c in the strongly magnetized simulations. The results of the numerical simulations are compared to theoretical predictions from a normal mode analysis of the linearized relativistic magnetohydrodynamic (RMHD) equations capable of describing a uniform axially magnetized cylindrical relativistic jet embedded in a uniform axially magnetized relativistically moving sheath. The theoretical dispersion relation allows investigation of effects associated with maximum possible sound speeds, Alfven wave speeds near light speed and relativistic sheath speeds. The prediction of increased stability of the weakly magnetized system resulting from c/2 sheath speeds and the stabilization of the strongly magnetized system resulting from c/2 sheath speeds is verified by the numerical simulation results.Comment: 31 pages, 8 figures, accepted for publicatin in ApJ. A paper with high resolution figures available at http://gammaray.nsstc.nasa.gov/~mizuno/research_new.htm

    Novel PHB/PCL scaffolds produced by melt base technologies

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    [Excerpt] On this work, the natural origin polymer Polyhydroxybutyrate (PHB) was melt blended with synthetic aliphatic polyester Polye-caprolactone (PCL). The ratio of PHB/PCL was varied from 25% to 75% by weight. These blends were further injection moulded and characterized. The thermal properties of the developed blends were accessed by differential scanning calorimetry DSC). The effect of the ratio PHB/PCL on the mechanical properties (tensile modulus and tensile strength) was determined by tensile tests. […]info:eu-repo/semantics/publishedVersio

    The complexity of pluralistic ignorance in Republican climate change policy support in the United States

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    Most Americans fail to recognize widespread public support for climate change action. Here we investigate how this phenomenon differs for Republican supporters versus opponents of several climate change policies. Surveying a representative sample of Republican voters (N = 1000), we find that misperception of in-group support for climate action is primarily restricted to Republicans already opposed to action. Specifically, those in the minority (i.e., Republicans opposed to climate action) were more likely to erroneously perceive other Republicans as holding views on climate change policy similar to their own. While Republican supporters recognize that most Republicans support climate change policy, they may be discouraged from expressing their support due to an information environment disproportionately portraying Republicans as opposed to climate change action

    Total energy intake and self-selected macronutrient distribution during wildland fire suppression

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    Introduction: Wildland firefighters (WLFF) work long hours in extreme environments resulting in high daily total energy expenditure (TEE). Increasing work shift eating episodes and/or providing rations that promote convenient feeding has shown augmented self-selected work output, as has regular carbohydrate (CHO) consumption. It remains unclear how current WLFF feeding strategies compare to more frequent nutrient delivery. Our study’s aim was to determine WLFFs’ self-selected field total energy intake (TEI), composition, and patterns feeding during wildland fire suppression shifts. Methods: 86 WLFF (16 female, 70 male; 27.5 ± 6.4 yr) deployed to fire incidents across the United States throughout the 2018 fire season. Pre- and post-shift food inventories collected at basecamp provided item-specific nutrient content (calories [kcal], CHO, fat, protein). Work shift consumption (TEI, feeding frequency, episodic composition) was monitored in real-time by field researchers on fireline via observational data capture using mobile tablets. Shift work output was determined via actigraph accelerometry. Results: Work shift length averaged 14.0 ± 1.1 hr, with a TEI of 6.3 ± 2.5 MJ (1494 ± 592 kcal) (51 ± 10, 37 ± 9, 13 ± 4% for CHO, fat, and protein, respectively). WLFF averaged 4.3 ± 1.6 eating episodes (1.4 ± 1.3 MJ [345 ± 306 kcal] and 44 ± 38 g CHO.episode-1). WLFF who consumed \u3e20 kcal.kg-1 averaged less sedentary activity than those consuming \u3c16 kcal.kg-1. Conclusion: The present work shift TEI approximates 33% of previously-determined WLFF TEE and demonstrates that current WLFF consumption patterns may not deliver adequate nutrients for the occupational demands
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