The formation of planetary disks and winds: an ultraviolet view

Planetary systems are angular momentum reservoirs generated during star formation. This accretion process produces very powerful engines able to drive the optical jets and the molecular outflows. A fraction of the engine energy is released into heating thus the temperature of the engine ranges from the 3000K of the inner disk material to the 10MK in the areas where magnetic reconnection occurs. There are important unsolved problems concerning the nature of the engine, its evolution and the impact of the engine in the chemical evolution of the inner disk. Of special relevance is the understanding of the shear layer between the stellar photosphere and the disk; this layer controls a significant fraction of the magnetic field building up and the subsequent dissipative processes ougth to be studied in the UV. This contribution focus on describing the connections between 1 Myr old suns and the Sun and the requirements for new UV instrumentation to address their evolution during this period. Two types of observations are shown to be needed: monitoring programmes and high resolution imaging down to, at least, milliarsecond scales.Comment: Accepted for publication in Astrophysics and Space Science 9 figure

Formation of X-ray emitting stationary shocks in magnetized protostellar jets

X-ray observations of protostellar jets show evidence of strong shocks heating the plasma up to temperatures of a few million degrees. In some cases, the shocked features appear to be stationary. They are interpreted as shock diamonds. We aim at investigating the physics that guides the formation of X-ray emitting stationary shocks in protostellar jets, the role of the magnetic field in determining the location, stability, and detectability in X-rays of these shocks, and the physical properties of the shocked plasma. We performed a set of 2.5-dimensional magnetohydrodynamic numerical simulations modelling supersonic jets ramming into a magnetized medium and explored different configurations of the magnetic field. The model takes into account the most relevant physical effects, namely thermal conduction and radiative losses. We compared the model results with observations, via the emission measure and the X-ray luminosity synthesized from the simulations. Our model explains the formation of X-ray emitting stationary shocks in a natural way. The magnetic field collimates the plasma at the base of the jet and forms there a magnetic nozzle. After an initial transient, the nozzle leads to the formation of a shock diamond at its exit which is stationary over the time covered by the simulations (~ 40 - 60 yr; comparable with time scales of the observations). The shock generates a point-like X-ray source located close to the base of the jet with luminosity comparable with that inferred from X-ray observations of protostellar jets. For the range of parameters explored, the evolution of the post-shock plasma is dominated by the radiative cooling, whereas the thermal conduction slightly affects the structure of the shock.Comment: Accepted for publication in Astronomy and Astrophysic

Defining a Benchmark Suite for Evaluating the Import of OWL Lite Ontologies

SemanticWeb tools should be able to correctly interchange ontologies and, therefore, to interoperate. This interchange is not always a straightforward task if tools have different underlying knowledge representation paradigms. This paper describes the process followed to define a benchmark suite for evaluating the OWL import capabilities of ontology development tools in a benchmarking activity in progress in the Knowledge Web European Network of Excellence

Accretion shocks in T Tauri stars: diagnosis via semiforbidden UV lines ratios

Numerical calculations of the structure of accretion shocks in T Tauri stars (TTSs) indicate that the C III]1909, O III]1661+1666 and Si III]1892 ultraviolet lines should have comparable intensities. We show how the density and the velocity of the accreted gas can be derived from these line ratios. We also indicate how these parameters can be used, together with other less reliable parameters such as the distance and the extinction, to derive the accretion rate and the accretion luminosity. It is shown that the line ratios as well as their absolute fluxes [as measured with the International Ultraviolet Explorer (IUE)] are in agreement with the predictions of the accretion-shock model. However, this method is best suited for the analysis of high-resolution data [such as those obtained with the Hubble Space Telescope (HST)] from which accurate fluxes can be determined and blended components (stellar atmosphere, winds) can also be properly subtracted out.Peer reviewe

Globalización, universidad y conocimientos subalternos: desafíos para la supervivencia cultural

This article questions the possibility of creating spaces in the university for a cultural critique of the processes of global transformation of late capitalism. This is manifested by the overflow of spatial restrictions to financial capital, which is introduced into cyberspace-understood as the confluence of artifacts, practices and power relations of information technologies in relation to market forces. Specifically, it addresses the question of the place of subaltern knowledge in the new world order and the need for a new critical agenda of the university and the "Global South" academy, in the face of the threats of a corporatized university model that has been imposing itself

Anemia megaloblástica: un reto diagnóstico para el facultativo. serie de casos clínicos

We describe the clinical and laboratory characteristics of 3 patients who had megaloblastic anemia with different etiologies. Two cases with a diagnosis of pernicious anemia, one of them related to an infection by Helicobacter pylori and the second one mediated by autoimmune mechanisms; In the last patient, megaloblastic anemia was the presenting form of a myelodysplastic syndrome. Subsequently, we present a common sense approach to the first contact with the patient with megaloblastic anemia and the therapeutic bases according to current evidence for their underlying pathologyDescribimos las características clínicas y de laboratorio de 3 individuos quienes cursaron con anemia megaloblástica con etiologías distintas. Dos casos con diagnóstico de anemia perniciosa, uno de ellos relacionado a infección por Helicobacter pilory y el segundo mediado por mecanismos autoinmunes; En el paciente restante la anemia megaloblástica fue la forma de presentación de un síndrome mielodisplásico. Posteriormente se presentará un abordaje con sentido común frente al primer contacto con el paciente con anemia megaloblástica y las bases terapéuticas según la evidencia actual para su patología de base

Implicit and semi-implicit well-balanced finite-volume methods for systems of balance laws

The aim of this work is to design implicit and semi-implicit high-order well-balanced finite-volume numerical methods for 1D systems of balance laws. The strategy introduced by two of the authors in some previous papers for explicit schemes based on the application of a well-balanced reconstruction operator is applied. The well-balanced property is preserved when quadrature formulas are used to approximate the averages and the integral of the source term in the cells. Concerning the time evolution, this technique is combined with a time discretization method of type RK-IMEX or RK-implicit. The methodology will be applied to several systems of balance laws.This work is partially supported by projects RTI2018-096064-B-C21 funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”, projects P18-RT-3163 of Junta de Andalucía and UMA18-FEDERJA-161 of Junta de Andalucía-FEDER-University of Málaga. G.Russo and S.Boscarino acknowledge partial support from the Italian Ministry of University and Research (MIUR), PRIN Project 2017 (No. 2017KKJP4X) entitled “Innovative numerical methods for evolu-tionary partial differential equations and applications”. I. Gómez-Bueno is also supported by a Grant from “El Ministerio de Ciencia, Innovación y Universidades”, Spain (FPU2019/01541) funded by MCIN/AEI/10.13039/501100011033 and “ESF Invest-ing in your future”. // Funding for open access charge: Universidad de Málaga/CBUA

Kinetic Approach to Multilayer Sorption: Equations of Isotherm and Applications

An analytical isotherm equation that describes the multilayer adsorption on fractal surfaces with adsorbate-adsorbate interactions (measured in terms of free energy) different from that of bulk liquid was developed. Assuming mathematical functionalities for the variation of the free energy, it is possible to evaluate the influence of the adsorbate-adsorbate interactions on the adsorption capacity of solids of high degree of surface irregularity. For those surfaces with relatively low degree of irregularity, it results that the free energy variation with the layer number in the multilayer region affects considerably the sorption capacity of the adsorbent, even for water activities lower than those corresponding to the monolayer moisture content. The energy interactions between adjacent adsorbate layers become less important as the fractal dimension of the adsorbent increases. For a fractal surface, the growing of the multilayer seems to mainly controlled by the degree of surface roughness characteristic of microporous adsorbents, where the volume and pore dimension are the true limitants to the sorption capacity. The isotherm equations obtained were tested fitting published experimental equilibrium data of various water vapor-biopolymer systems

Molecular gas in the warped galaxy NGC 4013

The edge-on spiral galaxy NGC4013 has been mapped in the J=2-1 and 1-0 lines of (CO)-C-12 with the IRAM 30m telescope (HPBW 13'' and 21''). CO emission is detected within a galactocentric radius, R similar to 100'' (5.5 Kpc), The radial molecular gas distribution consists of a ring-like source (of radius r(ring) similar to 1.5 kPc)) and a fast rotating nuclear disk (of radius r(nucl) similar to 500 pc)