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Full list of authors: Gurvits, Leonid I.; Paragi, Zsolt ; Casasola, Viviana; Conway, John; Davelaar, Jordy; Falcke, Heino; Fender, Rob; Frey, Sándor; Fromm, Christian M.; Miró, Cristina García; Garrett, Michael A.; Giroletti, Marcello; Goddi, Ciriaco; Gómez, José-Luis; van der Gucht, Jeffrey; Guirado, José Carlos; Haiman, Zoltán; Helmich, Frank; Humphreys, Elizabeth; Impellizzeri, Violette; Kramer, Michael; Lindqvist, Michael; Linz, Hendrik; Liuzzo, Elisabetta; Lobanov, Andrei P.; Mizuno, Yosuke; Rezzolla, Luciano; Roelofs, Freek; Ros, Eduardo; Rygl, Kazi L. J.; Savolainen, Tuomas; Schuster, Karl; Venturi, Tiziana; Wiedner, Martina C.; Zensus, J. Anton.-- This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. ; This paper presents the ESA Voyage 2050 White Paper for a concept of TeraHertz Exploration and Zooming-in for Astrophysics (THEZA). It addresses the science case and some implementation issues of a space-borne radio interferometric system for ultra-sharp imaging of celestial radio sources at the level of angular resolution down to (sub-) microarcseconds. THEZA focuses at millimetre and sub-millimetre wavelengths (frequencies above ∼ 300 GHz), but allows for science operations at longer wavelengths too. The THEZA concept science rationale is focused on the physics of spacetime in the vicinity of supermassive black holes as the leading science driver. The main aim of the concept is to facilitate a major leap by providing researchers with orders of magnitude improvements in the resolution and dynamic range in direct imaging studies of the most exotic objects in the Universe, black holes. The concept will open up a sizeable range of hitherto unreachable parameters of observational astrophysics. It unifies two major lines of development of space-borne radio astronomy of the past decades: Space VLBI (Very Long Baseline Interferometry) and mm- and sub-mm astrophysical studies with "single dish" instruments. It also builds upon the recent success of the Earth-based Event Horizon Telescope (EHT) – the first-ever direct image of a shadow of the super-massive black hole in the centre of the galaxy M87. As an amalgam of these three major areas of modern observational astrophysics, THEZA aims at facilitating a breakthrough in high-resolution high image quality studies in the millimetre and sub-millimetre domain of the electromagnetic spectrum. © 2021, The Author(s). ; With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709. ; Peer reviewed

This is an open access article. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. ; The coming decades will establish the exploration of the gravitational wave (GW) Universe over a broad frequency range by ground and space interferometers. Meanwhile, wide-field, high-cadence and sensitive surveys will span the electromagnetic spectrum from radio all the way up to TeV, as well as the high-energy neutrino window. Among the numerous classes of transients, γ–ray bursts (GRBs) have direct links with most of the hot topics that will be addressed, such as the strong gravity regime, relativistic shocks, particle acceleration processes, equation of state of matter at nuclear density, and nucleosynthesis of heavy elements, just to mention a few. Other recently discovered classes of transients that are observed throughout cosmological distances include fast radio bursts (FRBs), fast blue optical transients (FBOTs), and other unidentified high-energy transients. Here we discuss how these topics can be addressed by a mission called ASTENA (Advanced Surveyor of Transient Events and Nuclear Astrophysics, see Frontera et al. 18). Its payload combines two instruments: (i) an array of wide-field monitors with imaging, spectroscopic, and polarimetric capabilities (WFM-IS); (ii) a narrow field telescope (NFT) based on a Laue lens operating in the 50–600 keV range with unprecedented angular resolution, polarimetric capabilities, and sensitivity. © 2021, The Author(s). ; The ASTENA mission concept is the result of several development activities. We wish to acknowledge the support by the Italian Space Agency (ASI) and that by the AHEAD European program. Open access funding provided by Universita degli Studi di Ferrara within the CRUI-CARE Agreement. ; With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709. ; Peer reviewed

En El Salvador, las exigencias de transparencia sobre el gobierno actual son mayores que en los anteriores, que muchos demandantes de ahora fueron los tolerantes de antes, que la mayor distancia de este gobierno con importantes sectores empresariales hace a estos más críticos que antaño. Sin embargo, las actuales exigencias de transparencia tienen sus bases objetivas, muchas explicables por las expectativas que el mismo gobierno generó, como por la preocupante falta de transparencia y signos de corrupción que se están manifestando en ciertas esferas gubernamentales. No es extraño entonces que muchos se quejen ahora de esa incómoda transparencia.