The impact of red giant/AGB winds on AGN jet propagation

Dense stellar winds may mass-load the jets of active galactic nuclei, although it is unclear what are the time and spatial scales in which the mixing takes place. We study the first steps of the interaction between jets and stellar winds, and also the scales at which the stellar wind may mix with the jet and mass-load it. We present a detailed two-dimensional simulation, including thermal cooling, of a bubble formed by the wind of a star. We also study the first interaction of the wind bubble with the jet using a three-dimensional simulation in which the star enters the jet. Stability analysis is carried out for the shocked wind structure, to evaluate the distances over which the jet-dragged wind, which forms a tail, can propagate without mixing with the jet flow. The two-dimensional simulations point at quick wind bubble expansion and fragmentation after about one bubble shock crossing time. Three-dimensional simulations and stability analysis point at local mixing in the case of strong perturbations and relatively small density ratios between the jet and the jet dragged-wind, and to a possibly more stable shocked wind structure at the phase of maximum tail mass flux. Analytical estimates also indicate that very early stages of the star jet-penetration time may be also relevant for mass loading. The combination of these and previous results from the literature suggest highly unstable interaction structures and efficient wind-jet flow mixing on the scale of the jet interaction height, possibly producing strong inhomogeneities within the jet. In addition, the initial wind bubble shocked by the jet leads to a transient, large interaction surface. The interaction structure can be a source of significant non-thermal emission.Comment: Accepted for publication in Astronomy & Astrophysic

Clouds and red giants interacting with the base of AGN jets

Extragalactic jets are formed close to supermassive black-holes in the center of galaxies. Large amounts of gas, dust, and stars cluster in the galaxy nucleus, and interactions between this ambient material and the jet base should be frequent, having dynamical as well as radiative consequences. This work studies the dynamical interaction of an obstacle, a clump of matter or the atmosphere of an evolved star, with the innermost region of an extragalactic jet. Jet mass-loading and the high-energy outcome of this interaction are briefly discussed. Relativistic hydrodynamical simulations with axial symmetry have been carried out for homogeneous and inhomogeneous obstacles inside a relativistic jet. These obstacles may represent a medium inhomogeneity or the disrupted atmosphere of a red giant star. Once inside the jet, an homogeneous obstacle expands and gets disrupted after few dynamical timescales, whereas in the inhomogeneous case, a solid core can smoothen the process, with the obstacle mass-loss dominated by a dense and narrow tail pointing in the direction of the jet. In either case, matter is expected to accelerate and eventually get incorporated to the jet. Particles can be accelerated in the interaction region, and produce variable gamma-rays in the ambient matter, magnetic and photon fields. The presence of matter clumps or red giants into the base of an extragalactic jet likely implies significant jet mass-loading and slowing down. Fast flare-like gamma-ray events, and some level of persistent emission, are expected due to these interactions.Comment: 13 pages, 15 Figures, accepted for publication in Astronomy and Astrophysic

Propagation of Magnetic Avalanches in Mn12Ac at High Field Sweep Rates

Time-resolved measurements of the magnetization reversal in single crystals of Mn 12 Ac in pulsed magnetic fields, at magnetic field sweep rates from 1.5     kT / s up to 7     kT / s , suggest a new process that cannot be scaled onto a deflagrationlike propagation driven by heat diffusion. The sweep rate dependence of the propagation velocity, increasing from a few 100     m / s up to the speed of sound in Mn 12 Ac , indicates the existence of two new regimes at the highest sweep rates, with a transition around 4     kT / s that can be understood as a magnetic deflagration-to-detonation transition

Inflammatory monocytes require type I interferon receptor signaling to activate NK cells via IL-18 during a mucosal viral infection

The requirement of type I interferon (IFN) for natural killer (NK) cell activation in response to viral infection is known, but the underlying mechanism remains unclear. Here, we demonstrate that type I IFN signaling in inflammatory monocytes, but not in dendritic cells (DCs) or NK cells, is essential for NK cell function in response to a mucosal herpes simplex virus type 2 (HSV-2) infection. Mice deficient in type I IFN signaling, Ifnar(-/-) and Irf9(-/-) mice, had significantly lower levels of inflammatory monocytes, were deficient in IL-18 production, and lacked NK cell-derived IFN-gamma. Depletion of inflammatory monocytes, but not DCs or other myeloid cells, resulted in lower levels of IL-18 and a complete abrogation of NK cell function in HSV-2 infection. Moreover, this resulted in higher susceptibility to HSV-2 infection. Although Il18(-/-) mice had normal levels of inflammatory monocytes, their NK cells were unresponsive to HSV-2 challenge. This study highlights the importance of type I IFN signaling in inflammatory monocytes and the induction of the early innate antiviral response

Large Nonreciprocal Propagation of Surface Acoustic Waves in Epitaxial Ferromagnetic/Semiconductor Hybrid Structures

Nonreciprocal propagation of sound, that is, the different transmission of acoustic waves traveling in opposite directions, is a challenging requirement for the realization of devices such as acoustic isolators and circulators. Here, we demonstrate efficient nonreciprocal transmission of surface acoustic waves (SAWs) propagating in opposite directions in a GaAs substrate coated with an epitaxial Fe3Si film. The nonreciprocity arises from the acoustic attenuation induced by the magnetoelastic (ME) interaction between the SAW strain field and spin waves in the ferromagnetic film, which depends on the SAW propagation direction and can be controlled via the amplitude and orientation of an external magnetic field. The acoustic-transmission nonreciprocity, defined as the difference between the transmitted acoustic powers for forward and backward propagation at the ME resonance, reaches values of up to 20%, which are, to our knowledge, the largest values of nonreciprocity reported for SAWs traveling in a semiconducting piezoelectric substrate covered by a ferromagnetic film. The experimental results are well accounted for by a model for the ME interaction, which also shows that the nonreciprocity can be further enhanced by optimization of the sample design. These results make Fe3Si/GaAs a promising platform for the realization of efficient nonreciprocal SAW devices

A Comparative Study of Benchtop and Portable NIR and Raman Spectroscopic Methods for the Quantitative Determination of Curcuminoids in Turmeric Powder

Turmeric consumption is continually increasing worldwide. Curcuminoids are major active constituents in turmeric and are associated with numerous health benefits. A combination of spectroscopic methods and chemometrics shows the suitability of turmeric for food quality control due to advantages such as speed, versatility, portability, and no need for sample preparation. Five calibration models to quantify curcuminoids in turmeric were proposed using benchtop and portable devices. The most remarkable results showed that Raman and NIR calibration models present an excellent performance reporting RMSEP of 0.44% w/w and 0.41% w/w, respectively. In addition, the five proposed methods (FT-IR, Raman, and NIR) were compared in terms of precision and accuracy. The results showed that benchtop and portable methods were in good agreement and that there are no significant differences between them. This study aims to foster the use of portable devices for food quality control in situ by demonstrating their suitability for the purpose

Manejo y producción de hortalizas bajo los principios de la agricultura orgánica en el altiplano de Oriente Antioqueño

La presente investigación se llevó a cabo en parcelas de agricultores de las veredas Las Mercedes, Alto del Mercado, Salto Abajo y El Chagualo del municipio de Marinilla, Antioquia. Estas veredas se encuentran ubicadas a alturas promedio de 2.100 metros sobre el nivel del mar, con temperaturas entre 15-18°C, un promedio anual de lluvias de 1.800-2.000 mm/año, humedad relativa del 75-80% y en la zona de vida bh-MB, según la clasificación de Holdridge. El trabajo consistió en evaluar durante dos semestres consecutivos, diferentes fuentes de fertilización orgánica e inorgánica y pesticidas naturales en la producción y calidad de los arreglos Brócoli // Lechuga, Repollo blanco // Repollo morado, Papa criolla II Lechuga y Zanahoria II Remolacha. En todos los ensayos de fertilización los rendimientos más sobresalientes se obtuvieron cuando se mezcló gallinaza más fertilizante químico. Por costos se presenta como promisoria la gallinaza más roca fosfórica en la sustitución del fertilizante químico. En la evaluación de los pesticidas naturales, el Badilus thuringiensis y el extracto de Melia sp. (Biomel) fueron efectivos en el control de la polilla dorso de diamante (Plutella xylostella) y de la pulgilla de la papa (Epítrix sp.), respectivamente. Los extractos de ortiga, manzanilla, cola de caballo y desincol floral no fueron efectivos contra Mycosphaerella brassicola, Xanthomonas campestris, Alternaría dauci, Cercospora veticola y Phytophthora infestans, respectivamente.Brócoli-Brassica oleracea var. italicaLechuga-Lactuca sativaZanahoria-Daucus carotaRemolacha-Beta vulgari

Frequency and predictors of thrombus inside the guiding catheter during interventional procedures: an optical coherence tomography study

Optical coherence tomography (OCT) is able to identify thrombus. We detect the frequency of thrombus inside the guiding catheter by OCT and its relationship with clinical and procedural factors. We screened 77 patients who underwent OCT pullbacks. Only patients with visible guiding catheter were finally included (35) and divided into thrombus (21) or no-thrombus group (14). Patients within thrombus group were mostly males (100 vs. 71 %, p = 0.05), with acute coronary syndrome (76 vs. 36 %, p = 0.02) and received more frequently percutaneous coronary intervention (86 vs. 43 %, p = 0.01) as compared to other group. A second dose of heparin was more frequently administered in thrombus than in other group (86 vs. 50 %, p = 0.01). Time between first heparin administration and OCT pullback (41[28–57] vs. 20 min [10–32], p = 0.001), time elapsed from second heparin administration and OCT pullback (29 [19–48] vs. 16 min [12–22], p = 0.002) and total procedural time (47 [36–69] vs. 31 min [26–39], p = 0.005) were longer in thrombus compared to other group. At multivariate analysis, total procedural time and time between first heparin administration and OCT pullback were only predictors of intra-catheter thrombus (HR 0.6 [0.3–0.9], p = 0.03 and HR 1.9 [1.1–3.2], p = 0.02, respectively). Thrombus inside guiding catheter may be a frequent finding in long interventional procedure. Future studies are warranted to determine its clinical impact