The throughput calibration of the VERITAS telescopes

Imaging atmospheric Cherenkov telescopes are continuously exposed to varying weather conditions that have short and long-term effects on their response to Cherenkov light from extensive air showers. This work presents the implementation of a throughput calibration method for the VERITAS telescopes taking into account changes in the optical response and detector performance over time. Different methods to measure the total throughput of the instrument, which depend on mirror reflectivites and PMT camera gain and efficiency, are discussed as well as the effect of its evolution on energy thresholds, effective collection areas, and energy reconstruction. The application of this calibration in the VERITAS data analysis chain is discussed, including the validation using Monte Carlo simulations and observations of the Crab Nebula.Comment: 7 pages, 4 figures, ICRC2021 Conference (Berlin, online

Lexical processing of ambiguous words: dominance or associative strength?

Four experiments examined the role of meaning frequency (dominance) and associative strength (measured by associative norms) in the processing of ambiguous words in isolation. Participants made lexical decisions to targets words that were associates of the more frequent (dominant) or less frequent (subordinate) meaning of a homograph prime. The first two experiments investigated the role of associative strength at long SOAs (Stimulus Onset Asynchrony) (750 ms.), showing that meaning is facilitated by the targets’ associative strength and not by their dominance. The last two experiments traced the role associativestrength at short SOAs (250 ms), showing that the manipulation of the associative strength has no effect in the semantic priming. The conclusions are: on the one hand, semantic priming for homographs is due to associative strength manipulations at long SOAs. On the other hand, the manipulation of the associative strength has no effect when automatic processes (short SOAs) are engaged for homographs.A través de cuatro experimentos, se examinó el papel de la frecuencia del significado (dominancia) y de la fuerza asociativa (medida mediante normas asociativas) en el procesamiento de palabras ambiguas aisladas. Los participantes tomaron decisiones léxicas acerca de palabras meta que eran las asociadas del significado más frecuente (dominante) o menos frecuente (subordinado) de un homógrafo primo. Los primeros dos experimentos investigaron el papel de la fuerza asociativa en las SOAs (asincronía del comienzo del estímulo) largas (750 ms), demostrando que el significado se ve facilitado por la fuerza asociativa de la meta y no por su dominancia. Los segundos experimentos trazaron el papel de la fuerza asociativa en las SOAs cortas (250 ms), demostrando que la manipulación de la fuerza asociativa no influye en la ceba semántica. Se concluye que: (a) la ceba semántica para homográficos se debe a las manipulaciones de la fuerza asociativa en las SOAs largas y (b) la manipulación de la fuerza asociativa no tiene ningún efecto cuando los procesos automáticos (SOAs cortas) están ocupados para los homógrafos

Long-term monitoring of the radio-galaxy M87 in gamma-rays: joint analysis of MAGIC, VERITAS and Fermi-LAT data

M87 was discovered in the very-high-energy band (VHE, E > 100 GeV) with HEGRA in 2003, long before its emission was detected in the high-energy band (HE, E > 100 MeV) with Fermi-LAT in 2009, opening the window to a new family of extragalactic sources with tilted jets. After a series of major VHE flares in 2005, 2008, and 2010, which were detected in multiple bands, the source has been found in a low activity state, interrupted only by comparatively smaller-scale flares. MAGIC and VERITAS, two stereoscopic Cherenkov telescope arrays located at Roque de los Muchachos Observatory (Canary Islands, Spain) and the Fred Lawrence Whipple Observatory (Arizona, US), have monitored M87 continuously and in coordination for more than 10 years. In this work, we present the data for 4 years of MAGIC and VERITAS observations corresponding to 2019, 2020, 2021 and 2022. The resulting light curves are shown in daily and monthly scales where no significant variability is observed. In addition, we show the first joint analysis using combined event data from the two VHE instruments and Fermi-LAT to compute the spectral energy distribution

La vegetación de ribera como indicadora de calidad ambiental en ríos serranos de la provincia de San Luis (Argentina)

The quality of the rivers can be analyzed using the characteristics of the vegetation of its banks. Nowadays, these habitats are being degraded at an accelerated rate by human disturbance. The aim of this study was to use the riparian vegetation of three rivers of the Sierra de San Luis (Argentina) as an indicator of the quality of aquatic environments. Fourteen phytosociological inventories were conducted in randomly selected sites on the banks of Potrero, El Volcán and El Trapiche rivers. In addition to the inventories, an anthropization index was calculated and a total of 23 alterations were identified. Each of these were assigned a value 0 (zero), 1 (low), 2 (medium) and 3 (high). These values were summed up to obtain a final score for each site. The results indicated that areas with higher anthropization possess a higher richness and coverage of invasive plants species, which are characteristic of disturbed sites. The site with the highest human disturbance was located on the banks of river El Volcán, while the lowest value was found in Potrero river. It can be inferred that invasive plants and the riparian communities’ characteristics are good indicators of the environmental quality of these rivers.Facultad de Ciencias Naturales y Muse

La vegetación de ribera como indicadora de calidad ambiental en ríos serranos de la provincia de San Luis (Argentina)

The quality of the rivers can be analyzed using the characteristics of the vegetation of its banks. Nowadays, these habitats are being degraded at an accelerated rate by human disturbance. The aim of this study was to use the riparian vegetation of three rivers of the Sierra de San Luis (Argentina) as an indicator of the quality of aquatic environments. Fourteen phytosociological inventories were conducted in randomly selected sites on the banks of Potrero, El Volcán and El Trapiche rivers. In addition to the inventories, an anthropization index was calculated and a total of 23 alterations were identified. Each of these were assigned a value 0 (zero), 1 (low), 2 (medium) and 3 (high). These values were summed up to obtain a final score for each site. The results indicated that areas with higher anthropization possess a higher richness and coverage of invasive plants species, which are characteristic of disturbed sites. The site with the highest human disturbance was located on the banks of river El Volcán, while the lowest value was found in Potrero river. It can be inferred that invasive plants and the riparian communities’ characteristics are good indicators of the environmental quality of these rivers.Facultad de Ciencias Naturales y Muse

Azospirillum brasilense Az39, a model rhizobacterium with AHL quorum quenching capacity

AimsThe aim of this research was to analyze the Quorum sensing (QS) and Quorum quenching (QQ) mechanisms based on N‐acyl‐L‐homoserine lactones (AHLs) in A. brasilense Az39, a strain with remarkable capacity to benefit a wide range of crops under agronomic conditions. Methods and ResultsWe performed an in silico and in vitro analysis of the quorum mechanisms in A. brasilense Az39. The results obtained in vitro using the reporter strains C. violaceum and A. tumefaciens and Liquid Chromatography coupled to Mass‐Mass Spectrometry (LC‐MS/MS) analysis showed that although Az39 does not produce AHL molecules, it is capable of degrading them by at least two hypothetical enzymes identified by bioinformatics approach, associated to the bacterial cell. In Az39 cultures supplemented with 500 nmol l−1 of the C3 unsubstituted AHLs (C4, C6, C8, C10, C12, C14), AHL levels were lower than in non‐inoculated LB media controls. Similar results were observed upon addition of AHLs with hydroxy (OH‐) and keto (oxo‐) substitutions in carbon 3. These results not only demonstrate the ability of Az39 to degrade AHLs. They also show the wide spectrum of molecules that can be degraded by this bacterium. ConclusionsAlthough A.brasilense Az39 is a silent bacterium unable to produce AHL signals, it is able to interrupt the communications between other bacteria and/or plants by a quorum quenching activity

Reading-related Cognitive Deficits in Spanish Developmental Dyslexia

AbstractSpanish-speaking children learn to read words written in a relatively transparent orthography. Variations in orthographic transparency may shape the manifestation of reading difficulties. This study was intended to help clarify the nature of developmental dyslexia in Spanish. Developmentally Dyslexic children (DD) were compared to a chronological age-matched control group (CA). Measures included rapid automated naming, verbal working memory, phonological short-term memory, and phonemic awareness. Results demonstrated that developmental dyslexics show reading-related cognitive deficits in areas such as naming speed, verbal working memory, phonological short-term memory, and phonemic awareness. Our results are consistent with studies conducted in the Spanish language and in other transparent orthographies