112 research outputs found
Modesto Armijo Lozano. Diario dedicado a su esposa, Carmenza Mejía Aráuz
Como parte de abonar al estudio de la historia de Centroamérica la doctora Monica Toussaint y el doctor Guillermo Fernández Ampié editaron: Modesto Armijo Lozano, Diario dedicado a su esposa, Carmenza Mejía Aráuz (octubre 1926- julio 19279).Incluido en la colección Testimonios del Instituto Mora. El texto publicado en 2015 puede considerarse una valiosa fuente histórica para analizar la Guerra Constitucionalista nicaragüense (1926-1927) que involucró a los países centroamericanos, Estados Unidos y México. Si bien Modesto Armijo, quien fue parte del gabinete de gobierno de Juan Bautista Sacasa durante la Guerra Constitucionalista, es un personaje poco conocido dentro de la historiografía nicaragüense y centroamericana. La publicación de su Diario es una muestra de que aún a inicios del siglo XXI existen episodios y procesos históricos que no terminan de revisarse, y queda mucho por analizar y develar
El antimperialismo de Froylán Turcios: reflexiones para el estudio de la Revista Ariel
En 2013 viajé a Managua y Tegucigalpa para realizar trabajos de archivo que pudiera fundamentar mi investigación de maestría sobre Augusto C. Sandino y México. De ante mano tenía conocimiento que para poder estudiar seriamente el movimiento sandinista de los años veinte era indispensable consultar Revista Ariel, así que uno de mis principales objetivos dentro de ese proceso de investigación fue encontrar y consultar la publicación dirigida por el intelectual hondureño Froylán Turcios. Después de una interesante travesía pude encontrar la Revista Ariel en Tegucigalpa, sin embargo las condiciones en que se incontraba la colección imposibilitó su consulta. Así que solo pude analizar aquellos ejemplares que no corrían el riesgo de dañarse. Durante el proceso de sistematización de la información recuperada pude dimensionar la importancia que esta publicación y su editor Turcios tuvo en la lucha antiimperialista latinoamericana y en la construcción de una identidad continental durante las primeras décadas del siglo XX. Este artículo tiene la intensión de analizar la Revista Ariel a partir de una serie de variables metodológicas señalando la relevancia de la dimensión política que tuvo esta y el resto de revistas culturales en América Latina, no solo por los temas y debates que albergaron sino por su incidencia en la realidad latinoamericana. El análisis arroja una problemática que debe considerarse al estudiarse el antiimperialismo latinoamericano desde esta perspectiva: la dispersión física de la revista, el descuido de la colección existente y aún más grave, lo incompleto de las mismas
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
A search for ultra-high-energy photons at the Pierre Auger Observatory exploiting air-shower universality
The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above ∼0.2 EeV. It measures extensive air showers using a hybrid technique that combines a fluorescence detector (FD) with a ground array of particle detectors (SD). The signatures of a photon-induced air shower are a larger atmospheric depth at the shower maximum (X) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced background. Using observables measured by the FD and SD, three photon searches in different energy bands are performed. In particular, between threshold energies of 1-10 EeV, a new analysis technique has been developed by combining the FD-based measurement of X with the SD signal through a parameter related to its muon content, derived from the universality of the air showers. This technique has led to a better photon/hadron separation and, consequently, to a higher search sensitivity, resulting in a tighter upper limit than before. The outcome of this new analysis is presented here, along with previous results in the energy ranges below 1 EeV and above 10 EeV. From the data collected by the Pierre Auger Observatory in about 15 years of operation, the most stringent constraints on the fraction of photons in the cosmic flux are set over almost three decades in energy
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