884 research outputs found

    ¿El TLC con estados unidos es la puerta a la marginación del sector agropecuario en Colombia?

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    Este ensayo sobre la marginación del sector agropecuario por la entrada en vigor del TLC con Estados Unidos, se hace un análisis desde siglos anteriores como ha sido esa forma de abrir la fronteras para la comercialización de bienes y servicios sin cobro de aranceles, que países y bajo que convenios se empezó a usar este tipo acuerdos. De ese recuento histórico sigue el estudio, el cual se enfoca en las ventajas y desventajas que puede llegar a tener este tipo de acuerdos para el sector agropecuario en el país, que tan competitivo este sector puede llegar hacer con su par en Estados Unidos, que tan avanzados en infraestructura esta en país para ser más agiles a la hora de comercializar nacional e internacionalmente sus productos, para eso se analizara que políticas se han implementado desde la apertura económica, y que tanto el gobierno ayuda a este sector como lo hace el país americano, de ahí parte como los negociadores de un lado y otro plantearon una matriz con sus necesidades para así saber cómo negociar y que le conviene a un país u otro, ya que por ser culturalmente distintos sus necesidades son diferentes, y Colombia por ser un país tropical produce alimentos que en el país del norte no se consumen, es por eso que Colombia tiene que acomodarse a las necesidades del país para sacar máximo provecho.This essay on the marginalization of the agricultural sector by the entry into force of the FTA with the United States, an analysis from previous centuries as has been the way to open the borders for the marketing of goods and services without charging tariffs that countries and under that agreement began to use such agreements. In this historical account is the study, which focuses on the advantages and disadvantages that can have this type of agreement for the agricultural sector in the country, how competitive this industry can do with your couple in the United States, which infrastructure so advanced in this country to be more agile to commercialize its products nationally and internationally, for that you analyze which policies have been implemented since the economic opening, and that both government help this sector as does the American country, from there, as negotiators from both sides raised a matrix with your requirements and know how to negotiate and is best for one country or another, as being culturally different their needs are different, and Colombia for being a tropical country food produced in the north country is not consumed, is why Colombia has to accommodate the needs of the country to take full advantage

    Debates y Reformas a las policías en Chile, Colombia y Ecuador: Un estudio comparativo

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    Chile, Colombia and Ecuador have experienced attempts of police reform in response to the need to generate change within these institutions. This research aims to identify the events that led to police reform processes in the three cases, generating a comparison between the processes and debates around police reforms, emphasizing common actors and socio-political processes to establish convergences and differences in the reform processes. As well as contributing to a debate on police institutionality and the paradigms from which citizen security and public order are discussed, especially as a result of the human rights violations committed by the police in these countries.Chile, Colombia y Ecuador han experimentado una creciente demanda de reformas policiales por parte de la ciudadanía, surgidas luego de la respuesta policial ante masivas protestas ocurridas en los 3 países durante el año 2019. Esta investigación apunta a comparar los procesos de reforma policial en los tres países seleccionados, buscando elementos convergentes en los discursos con los que actores políticos han abordado las propuestas a las reformas policiales, contextualizándolas dentro de la historia de cada una de las instituciones que cumplen la función policial: Carabineros de Chile, Policía Nacional de Ecuador y la Policía Nacional de Colombia. Con esto pretendemos aportar al debate sobre la institucionalidad policial y los paradigmas desde los que se discute la seguridad ciudadana y el orden público sobre todo a raíz de las violaciones a derechos humanos presentes en los países por parte de la fuerza policial

    MAGIC very large zenith angle observations of the Crab Nebula up to 100 TeV

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    Aims. We measure the Crab Nebula gamma-ray spectral energy distribution in the 100 TeV energy domain and test the validity of existing leptonic emission models at these high energies.Methods. We used the novel very large zenith angle observations with the MAGIC telescope system to increase the collection area above 10 TeV. We also developed an auxiliary procedure of monitoring atmospheric transmission in order to assure proper calibration of the accumulated data. This employs recording optical images of the stellar field next to the source position, which provides a better than 10% accuracy for the transmission measurements.Results. We demonstrate that MAGIC very large zenith angle observations yield a collection area larger than a square kilometer. In only 56 h of observations, we detect the gamma-ray emission from the Crab Nebula up to 100 TeV, thus providing the highest energy measurement of this source to date with Imaging Atmospheric Cherenkov Telescopes. Comparing accumulated and archival MAGIC and Fermi/LAT data with some of the existing emission models, we find that none of them provides an accurate description of the 1 GeV to 100 TeV gamma-ray signal

    Study of the GeV to TeV morphology of the gamma Cygni SNR (G 78.2+2.1) with MAGIC and Fermi-LAT: Evidence for cosmic ray escape

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    Artículo firmado por 183 autores. © ESO 2023. We would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF and MPG; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish MINECO (FPA2017-87859-P, FPA2017-85668-P, FPA2017-82729-C6-2-R, FPA2017-82729-C6-6-R, FPA2017-82729-C6-5-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2017-87055-C2-2-P, FPA2017-90566-REDC); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-268/16.12.2019 and the Academy of Finland grant no. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia "Severo Ochoa" SEV-2016-0588 and SEV-2015-0548, the Unidad de Excelencia "María de Maeztu" MDM-2014-0369 and the "la Caixa" Foundation (fellowship LCF/BQ/PI18/11630012), by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq and FAPERJ. The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat a l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucleaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K.A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Etudes Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515. This research made use of Astropy (http://www.astropy.org), a community-developed core Python package for Astronomy (Astropy Collaboration 2013, 2018).Context. Diffusive shock acceleration (DSA) is the most promising mechanism that accelerates Galactic cosmic rays (CRs) in the shocks of supernova remnants (SNRs). It is based on particles scattering caused by turbulence ahead and behind the shock. The turbulence upstream is supposedly generated by the CRs, but this process is not well understood. The dominant mechanism may depend on the evolutionary state of the shock and can be studied via the CRs escaping upstream into the interstellar medium (ISM). Aims. Previous observations of the gamma Cygni SNR showed a difference in morphology between GeV and TeV energies. Since this SNR has the right age and is at the evolutionary stage for a significant fraction of CRs to escape, our aim is to understand gamma-ray emission in the vicinity of the gamma Cygni SNR. Methods. We observed the region of the gamma Cygni SNR with the MAGIC Imaging Atmospheric Cherenkov telescopes between 2015 May and 2017 September recording 87 h of good-quality data. Additionally, we analysed Fermi-LAT data to study the energy dependence of the morphology as well as the energy spectrum in the GeV to TeV range. The energy spectra and morphology were compared against theoretical predictions, which include a detailed derivation of the CR escape process and their gamma-ray generation. Results. The MAGIC and Fermi-LAT data allowed us to identify three emission regions that can be associated with the SNR and that dominate at different energies. Our hadronic emission model accounts well for the morphology and energy spectrum of all source components. It constrains the time-dependence of the maximum energy of the CRs at the shock, the time-dependence of the level of turbulence, and the diffusion coefficient immediately outside the SNR shock. While in agreement with the standard picture of DSA, the time-dependence of the maximum energy was found to be steeper than predicted, and the level of turbulence was found to change over the lifetime of the SNR.Depto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de Ciencias FísicasTRUEGerman BMBFGerman MPGItalian INFNItalian INAFSwiss National Fund SNFERDF under the Spanish MINECOIndian Department of Atomic EnergyJapanese ICRRJapanese University of TokyoJapanese JSPSJapanese MEXTBulgarian Ministry of Education and Science, National RI Roadmap ProjectAcademy of FinlandCentro de Excelencia "Severo Ochoa"Unidad de Excelencia "Maria de Maeztu"Fundación "la Caixa"Croatian Science Foundation (HrZZ) ProjectUniversity of Rijeka ProjectDFG Collaborative Research CentersPolish National Research Centre grantBrazilian MCTICBrazilian CNPqBrazilian FAPERJDOEpu

    A search for dark matter in Triangulum II with the MAGIC telescopes

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    We present the first results from very-high-energy observations of the dwarf spheroidal satellite candidate Triangulum II with the MAGIC telescopes from 62.4 h of good-quality data taken between August 2016 and August 2017. We find no gamma-ray excess in the direction of Triangulum II, and upper limits on both the differential and integral gamma-ray flux are presented. Currently, the kinematics of Triangulum II are affected by large uncertainties leading to a bias in the determination of the properties of its dark matter halo. Using a scaling relation between the annihilation J-factor and heliocentric distance of well-known dwarf spheroidal galaxies, we estimate an annihilation J-factor for Triangulum II for WIMP dark matter of log[J(ann)(0.5 degrees)/GeV2 cm(-5)] = 19.35 +/- 0.37. We also derive a dark matter density profile for the object relying on results from resolved simulations of Milky Way sized dark matter halos. We obtain 95% confidence-level limits on the thermally averaged annihilation cross section for WIMP annihilation into various Standard Model channels. The most stringent limits are obtained in the tau(-)tau(+) final state, where a cross section for annihilation down to = 3.05 x 10(-24) cm(3) s(-1) is excluded. (C) 2020 Elsevier B.V. All rights reserved

    Bounds on Lorentz Invariance Violation from MAGIC Observation of GRB 190114C

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    On January 14, 2019, the Major Atmospheric Gamma Imaging Cherenkov telescopes detected GRB 190114C above 0.2 TeV, recording the most energetic photons ever observed from a gamma-ray burst. We use this unique observation to probe an energy dependence of the speed of light in vacuo for photons as predicted by several quantum gravity models. Based on a set of assumptions on the possible intrinsic spectral and temporal evolution, we obtain competitive lower limits on the quadratic leading order of speed of light modification

    Unraveling the Complex Behavior of Mrk 421 with Simultaneous X-Ray and VHE Observations during an Extreme Flaring Activity in 2013 April

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    We report on a multiband variability and correlation study of the TeV blazar Mrk 421 during an exceptional flaring activity observed from 2013 April 11 to 19. The study uses, among others, data from GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), Swift, Nuclear Spectroscopic Telescope Array (NuSTAR), Fermi Large Area Telescope, Very Energetic Radiation Imaging Telescope Array System (VERITAS), and Major Atmospheric Gamma Imaging Cherenkov (MAGIC). The large blazar activity and the 43 hr of simultaneous NuSTAR and MAGIC/VERITAS observations permitted variability studies on 15 minute time bins over three X-ray bands (3-7 keV, 7-30 keV, and 30-80 keV) and three very-high-energy (VHE; >0.1 TeV) gamma-ray bands (0.2-0.4 TeV, 0.4-0.8 TeV, and >0.8 TeV). We detected substantial flux variations on multi-hour and sub-hour timescales in all of the X-ray and VHE gamma-ray bands. The characteristics of the sub-hour flux variations are essentially energy independent, while the multi-hour flux variations can have a strong dependence on the energy of the X-rays and the VHE gamma-rays. The three VHE bands and the three X-ray bands are positively correlated with no time lag, but the strength and characteristics of the correlation change substantially over time and across energy bands. Our findings favor multi-zone scenarios for explaining the achromatic/chromatic variability of the fast/slow components of the light curves, as well as the changes in the flux-flux correlation on day-long timescales. We interpret these results within a magnetic reconnection scenario, where the multi-hour flux variations are dominated by the combined emission from various plasmoids of different sizes and velocities, while the sub-hour flux variations are dominated by the emission from a single small plasmoid moving across the magnetic reconnection layer

    Síndrome hemolítico urémico atípico, revisión de la literatura y documento de consenso. Enfoque diagnóstico y tratamiento

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    Atypical Hemolytic Uremic Syndrome is an ultra-orphan disease, more than 50% of patients die, need renal replacement therapy or have permanent renal failure within the first year of diagnostic. With current supportive care 9-15% of aHUS patients die within 1 year following a clinical manifestation of aHUS. Severe consequences of this disease reinforce the early diagnostic and treatment importance. Clinical manifestations of this disease include the classic triad of microangiopatic anemia, thrombocytopenia and end organ damage where the renal failure is the most common manifestation, although not the only one as neurological, cardiac and gastrointestinal complications are also apparent. Mutations on the complement system regulating proteins are recognized as the cause of this syndrome; however they are not identified in all patients as new mutations are continuously being identified. It has a high rate post-transplantation graft loss in 60% of the cases. Most known therapy for this disease, considered as the first line therapy was plasmapheresis; however it shows very poor results. Since 2011 we have a recombinant monoclonal antibody targeted to the complement component C5 (eculizumab), the only approved for the treatment of aHUS, which has proven to significantly improve the disease prognosis and progression, and is considered the first line therapy.El Síndrome Hemolítico Urémico atípico (SHUa) es una enfermedad ultra-huérfana; más del 50% de los pacientes muere, necesita terapia de remplazo renal o sufre insuficiencia renal terminal dentro del primer año de diagnóstico. Con el tratamiento de soporte actual (plasmaféresis o infusión deplasma) 9-15% de los pacientes de SHUa mueren dentro del lapso de 1 año, después de una manifestación clínica de hemólisis. Las consecuencias severas de esta enfermedad refuerzan la importancia del diagnóstico y tratamiento temprano. Las manifestaciones clínicas incluyen la triada clásica de anemia microangiopática, trombocitopenia y daño a otros órganos, donde la insuficiencia renal es la manifestación más común, frecuentemente asociada a otras complicaciones tales como neurológicas, cardíacas y gastrointestinales. Las mutaciones en las proteínas reguladoras del sistema del complemento son reconocidas como las causas de este síndrome; sin embargo, no se identifican en todos los pacientes con diagnóstico de SHUa. Existe una alta tasa de pérdida del injerto postrasplante renal, en aproximadamente 60% de los casos.La plasmaféresis, considerada como terapia de primera línea, no ha demostrado resultados satisfactorios a largo plazo. Desde el año 2011 está disponible en Colombia un anticuerpo monoclonal recombinante dirigido contra el complemento a nivel C5 (eculizumab), medicamento único aprobado para el tratamiento del SHUa. Este tratamiento ha demostrado mejorar, de manera significativa, el pronóstico y la progresión de la enfermedad, y es considerado la primera línea de terapia hoy en día

    Broadband characterisation of the very intense TeV flares of the blazar 1ES 1959+650 in 2016

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    1ES 1959+650 is a bright TeV high-frequency-peaked BL Lac object exhibiting interesting features like "orphan" TeV flares and broad emission in the high-energy regime that are difficult to interpret using conventional one-zone Synchrotron Self-Compton (SSC) scenarios. We report the results from the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) observations in 2016 along with the multi-wavelength data from the Fermi Large Area Telescope (LAT) and Swift instruments. MAGIC observed 1ES 1959+650 with different emission levels in the very-high-energy (VHE, E> 100 GeV) gamma -ray band during 2016. In the long-term data, the X-ray spectrum becomes harder with increasing flux and a hint of a similar trend is also visible in the VHE band. An exceptionally high VHE flux reaching similar to 3 times the Crab Nebula flux was measured by MAGIC on the 13 and 14 of June, and 1 July 2016 (the highest flux observed since 2002). During these flares, the high-energy peak of the spectral energy distribution (SED) lies in the VHE domain and extends up to several TeV. The spectrum in the gamma -ray (both Fermi-LAT and VHE bands) and the X-ray bands are quite hard. On 13 June and 1 July 2016, the source showed rapid variations in the VHE flux within timescales of less than an hour. A simple one-zone SSC model can describe the data during the flares requiring moderate to large values of the Doppler factors (delta >= 30-60). Alternatively, the high-energy peak of the SED can be explained by a purely hadronic model attributed to proton-synchrotron radiation with jet power L-jet similar to 10(46) erg s(-1) and under high values of the magnetic field strength (similar to 100 G) and maximum proton energy (similar to few EeV). Mixed lepto-hadronic models require super-Eddington values of the jet power. We conclude that it is difficult to get detectable neutrino emission from the source during the extreme VHE flaring period of 2016
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