Performance study update of observations in divergent mode for the Cherenkov Telescope Array

Due to the limited field of view (FoV) of Cherenkov telescopes, the time needed to achieve target sensitivity for surveys of the extragalactic and Galactic sky is large. To optimize the time spent to perform such surveys, a so-called "divergent mode" of the Cherenkov Telescope Array Observatory (CTAO) was proposed as an alternative observation strategy to the traditional parallel pointing. In the divergent mode, each telescope points to a position in the sky that is slightly offset, in the outward direction, from the original center of the field of view. This bring the advantage of increasing the total instantaneous arrays' FoV. From an enlarged field of view also benefits the search for very-high-energy transient sources, making it possible to cover large sky regions in follow-up observations, or to quickly cover the probability sky map in case of Gamma Ray Bursts (GRB), Gravitational Waves (GW), and other transient events. In this contribution, we present the proposed implementation of the divergent pointing mode and its first preliminary performance estimation for the southern CTAO array

Performance study update of observations in divergent mode for the Cherenkov Telescope Array

Due to the limited field of view (FoV) of Cherenkov telescopes, the time needed to achieve target sensitivity for surveys of the extragalactic and Galactic sky is large. To optimize the time spent to perform such surveys, a so-called "divergent mode" of the Cherenkov Telescope Array Observatory (CTAO) was proposed as an alternative observation strategy to the traditional parallel pointing. In the divergent mode, each telescope points to a position in the sky that is slightly offset, in the outward direction, from the original center of the field of view. This bring the advantage of increasing the total instantaneous arrays' FoV. From an enlarged field of view also benefits the search for very-high-energy transient sources, making it possible to cover large sky regions in follow-up observations, or to quickly cover the probability sky map in case of Gamma Ray Bursts (GRB), Gravitational Waves (GW), and other transient events. In this contribution, we present the proposed implementation of the divergent pointing mode and its first preliminary performance estimation for the southern CTAO array.Comment: Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219

Hunting for dark matter and new physics with GECCO

We outline the science opportunities in the areas of searches for dark matter and new physics offered by a proposed future MeV gamma-ray telescope, the Galactic Explorer with a Coded Aperture Mask Compton Telescope (GECCO). We point out that such an instrument would play a critical role in opening up a discovery window for particle dark matter with mass in the MeV or sub-MeV range, in disentangling the origin of the mysterious 511 keV line emission in the Galactic Center region, and in potentially discovering Hawking evaporation from light primordial black holes

Estilos de aprendizaje de los estudiantes de medicina veterinaria de la Universidad Nacional de Rosario, Argentina

El objetivo del trabajo fue identificar los estilos de aprendizaje predominantes de los estudiantes de medicina veterinaria y determinar si existen diferencias en las preferencias cognitivas entre los alumnos del ciclo de formación básica y superior de la carrera. Para ello se encuestaron 76 estudiantes de la Universidad Nacional de Rosario (Argentina), aplicando el inventario de estilos de aprendizaje de Felder y Silverman, que valora la preferencia hacia los estilos activo o reflexivo (tipo de procesamiento), sensorial o intuitivo (tipo de percepción), visual o verbal (tipo de representación) y secuencial o global (tipo de comprensión). Las preferencias cognitivas de los estudiantes encuestados de ambos ciclos de formación se orientaron hacia lo activo, sensorial, visual y secuencial. Sin embargo, en el ciclo básico se hallaron diferencias estadísticamente significativas en los estilos de procesamiento y percepción según año de ingreso. Así, los estudiantes con dos o más años de trayectoria en la carrera presentaron mayores grados de preferencia por los estilos activo y sensorial que los ingresantes. Estos resultados apoyan la hipótesis de diferencias cognitivas en el aprendizaje. En este estudio se comprobó que la mayor parte de los estudiantes analizados prefieren aprender mediante los estilos activo, sensorial, visual y secuencial. Además, existe una profundización de estas preferencias a medida que permanecen más años en la carrera. La evaluación de las características psicológicas del alumnado permitiría el diseño de clases adecuadas a sus necesidades educativas facilitando la construcción de conocimientos en la universidad

Composition, distribution and trophic relationships of the fish fauna of the Negro river, Patagonia Argentina

La provincia ictiogeográfica Patagónica se caracteriza por una llamativa pobreza de especies. El río Negro es el curso de agua más importante de esta región y a pesar de sus dimensiones e importancia socioeconómica su fauna íctica ha sido poco estudiada. Este trabajo describe algunos aspectos biogeográficos y características ecológicas de su ictiofauna. Se muestrearon estacionalmente cinco sitios a lo largo del río, por medio de redes de enmalle, pesca eléctrica, redes de arrastre costero y atarraya. Se analizó la composición y distribución de peces y se estudió la dieta para determinar los roles tróficos y los niveles de competencia y de piscivoría. Se capturaron ejemplares de 13 especies: siete de origen nativo y seis exóticas, de las cuales se destaca la novedosa presencia de la coridora (Corydoras paleatus) y la carpa común (Cyprinus carpio), ampliando su distribución austral. Las especies más importantes fueron las nativas pejerrey patagónico (Odontesthes hatcheri), perca bocona (Percychthis colhuapiensis), perca de boca chica (P. trucha) y madrecita (Jenynsia multidentata). Los índices ecológicos indican que el curso inferior es diferente al resto del río presentando una dominancia de pejerrey patagónico y madrecita. En este sector se observó una mayor importancia de especies exóticas. Se encontraron ocho grupos tróficos, existencia de solapamientos en las dietas entre componentes nativos y exóticos, y evidencia de piscivoría importante entre las especies. La presencia y distribución de los peces en el río Negro está fuertemente influenciada por fenómenos de antropocoria accidental o intencional. Es necesario desarrollar estudios que analicen el impacto generado por las introducciones y la evolución de las relaciones entre los componentes nativos y exóticos, teniendo en cuenta que la trucha arco iris y la carpa común han influido negativamente en otros lugares del mundo.The Patagonic ictiogeographic region is characterized by a low species diversity. Despite that the Negro river is the most important water body in the region, both in terms of the size of its drainage basin and of its socioeconomic importance, its fish fauna has scarcely been studied. The present paper addresses biogeographic and ecological characteristics related to its fish. Gill net gangs, electro fishing and beach seine nets were used to sample seasonally five stations along the river. Fish fauna composition and distribution were analyzed throughout different ecological indexes. Diet composition was also analyzed to establish trophic roles, competition and piscivory. We caught seven native and six exotic species; two of them (Corydoras paleatus and Cyprinus carpio) represent a widening of their austral distribution. The natives Odontesthes hatcheri, Percychthis colhuapiensis, P. trucha and Jenynsia multidentata were more important in terms of numbers in catches. Ecological indexes show that the lower part of the Negro river differs from the rest of the river with higher numbers of O. hatchery and J. multidentata. Eight trophic groups were found as well as evidence of diet overlapping and considerable piscivory. Presence and distribution of fish in the Negro river is strongly influenced by introduction by men, either accidentally or intentionally. Impacts by introduced species need to be addressed, specially in terms of emerging processes between native and exotic fish, taking into special consideration the negative impacts that the rainbow trout and the carp have already had in different parts of the world

Association of intronic variants of the KCNAB1 gene with lateral temporal epilepsy.

The KCNAB1 gene is a candidate susceptibility factor for lateral temporal epilepsy (LTE) because of its functional interaction with LGI1, the gene responsible for the autosomal dominant form of LTE. We investigated association between polymorphic variants across the KCNAB1 gene and LTE. The allele and genotype frequencies of 14 KCNAB1 intronic SNPs were determined in 142 Italian LTE patients and 104 healthy controls and statistically evaluated. Single SNP analysis revealed one SNP (rs992353) located near the 3'end of KCNAB1 slightly associated with LTE after multiple testing correction (odds ratio=2.25; 95% confidence interval 1.26-4.04; P=0.0058). Haplotype analysis revealed two haplotypes with frequencies higher in cases than in controls, and these differences were statistically significant after permutation tests (Psim=0.047 and 0.034). One of these haplotypes was shown to confer a high risk for the syndrome (odds ratio=12.24; 95% confidence interval 1.32-113.05) by logistic regression analysis. These results support KCNAB1 as a susceptibility gene for LTE, in agreement with previous studies showing that this gene may alter susceptibility to focal epilepsy

Impact of Aetiological Treatment on Conventional and Multiplex Serology in Chronic Chagas Disease

The main criterion for treatment effectiveness in Chagas Disease has been the seronegative conversion of previously reactive serology, generally achieved many years post-treatment. The lack of reliable tests to ensure parasite clearance and to examine the effect of treatment is the main difficulty in evaluating treatment for chronic Chagas disease. Decreases of conventional and non-conventional serological titers can be useful tools to monitor the early impact of treatment. We serially measured changes in antibody levels, including seronegative conversion as well as declines in titers in 53 benznidazole-treated and 89 untreated chronically T. cruzi-infected subjects. Seronegative conversion as well as decreases of titers was significantly higher in treated compared with untreated patients. A strong concordance was found between decreases of titers of conventional and non-conventional serologic tests post-treatment, reaffirming the findings. When seronegative conversion plus decreases of titers were considered altogether, the impact of treatment was higher, in a shorter follow-up period than previously considered. New tools for monitoring the effectiveness of treatment of chronic Chagas disease are necessary, and the results showed in this study is a contribution to researchers and physicians who assist patients suffering from this disease

White Paper and Roadmap for Quantum Gravity Phenomenology in the Multi-Messenger Era

The unification of quantum mechanics and general relativity has long been elusive. Only recently have empirical predictions of various possible theories of quantum gravity been put to test. The dawn of multi-messenger high-energy astrophysics has been tremendously beneficial, as it allows us to study particles with much higher energies and travelling much longer distances than possible in terrestrial experiments, but more progress is needed on several fronts. A thorough appraisal of current strategies and experimental frameworks, regarding quantum gravity phenomenology, is provided here. Our aim is twofold: a description of tentative multimessenger explorations, plus a focus on future detection experiments. As the outlook of the network of researchers that formed through the COST Action CA18108 "Quantum gravity phenomenology in the multi-messenger approach (QG-MM)", in this work we give an overview of the desiderata that future theoretical frameworks, observational facilities, and data-sharing policies should satisfy in order to advance the cause of quantum gravity phenomenology.Comment: Submitted to CQG for the Focus Issue on "Quantum Gravity Phenomenology in the Multi-Messenger Era: Challenges and Perspectives". Please contact us to express interesst of endorsement of this white pape

Multiwavelength study of the galactic PeVatron candidate LHAASO J2108+5157

Context. Several new ultrahigh-energy (UHE) γ-ray sources have recently been discovered by the Large High Altitude Air Shower Observatory (LHAASO) collaboration. These represent a step forward in the search for the so-called Galactic PeVatrons, the enigmatic sources of the Galactic cosmic rays up to PeV energies. However, it has been shown that multi-TeV γ-ray emission does not necessarily prove the existence of a hadronic accelerator in the source; indeed this emission could also be explained as inverse Compton scattering from electrons in a radiation-dominated environment. A clear distinction between the two major emission mechanisms would only be made possible by taking into account multi-wavelength data and detailed morphology of the source. Aims. We aim to understand the nature of the unidentified source LHAASO J2108+5157, which is one of the few known UHE sources with no very high-energy (VHE) counterpart. Methods. We observed LHAASO J2108+5157 in the X-ray band with XMM-Newton in 2021 for a total of 3.8 hours and at TeV energies with the Large-Sized Telescope prototype (LST-1), yielding 49 hours of good-quality data. In addition, we analyzed 12 years of Fermi-LAT data, to better constrain emission of its high-energy (HE) counterpart 4FGL J2108.0+5155. We used naima and jetset software packages to examine the leptonic and hadronic scenario of the multi-wavelength emission of the source. Results. We found an excess (3.7σ) in the LST-1 data at energies E > 3 TeV. Further analysis of the whole LST-1 energy range, assuming a point-like source, resulted in a hint (2.2σ) of hard emission, which can be described with a single power law with a photon index of Σ = 1.6 ± 0.2 the range of 0.3 - 100 TeV. We did not find any significant extended emission that could be related to a supernova remnant (SNR) or pulsar wind nebula (PWN) in the XMM-Newton data, which puts strong constraints on possible synchrotron emission of relativistic electrons. We revealed a new potential hard source in Fermi-LAT data with a significance of 4σ and a photon index of Σ = 1.9 ± 0.2, which is not spatially correlated with LHAASO J2108+5157, but including it in the source model we were able to improve spectral representation of the HE counterpart 4FGL J2108.0+5155. Conclusions. The LST-1 and LHAASO observations can be explained as inverse Compton-dominated leptonic emission of relativistic electrons with a cutoff energy of 100-30+70 TeV. The low magnetic field in the source imposed by the X-ray upper limits on synchrotron emission is compatible with a hypothesis of a PWN or a TeV halo. Furthermore, the spectral properties of the HE counterpart are consistent with a Geminga-like pulsar, which would be able to power the VHE-UHE emission. Nevertheless, the lack of a pulsar in the neighborhood of the UHE source is a challenge to the PWN/TeV-halo scenario. The UHE γ rays can also be explained as π0 decay-dominated hadronic emission due to interaction of relativistic protons with one of the two known molecular clouds in the direction of the source. Indeed, the hard spectrum in the LST-1 band is compatible with protons escaping a shock around a middle-aged SNR because of their high low-energy cut-off, but the origin of the HE γ-ray emission remains an open question

Observations of the Crab Nebula and Pulsar with the Large-sized Telescope Prototype of the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) is a next-generation ground-based observatory for gamma-ray astronomy at very high energies. The Large-Sized Telescope prototype (LST-1) is located at the CTA-North site, on the Canary Island of La Palma. LSTs are designed to provide optimal performance in the lowest part of the energy range covered by CTA, down to ≃20 GeV. LST-1 started performing astronomical observations in 2019 November, during its commissioning phase, and it has been taking data ever since. We present the first LST-1 observations of the Crab Nebula, the standard candle of very-high-energy gamma-ray astronomy, and use them, together with simulations, to assess the performance of the telescope. LST-1 has reached the expected performance during its commissioning period—only a minor adjustment of the preexisting simulations was needed to match the telescope’s behavior. The energy threshold at trigger level is around 20 GeV, rising to ≃30 GeV after data analysis. Performance parameters depend strongly on energy, and on the strength of the gamma-ray selection cuts in the analysis: angular resolution ranges from 0.°12-0.°40, and energy resolution from 15%-50%. Flux sensitivity is around 1.1% of the Crab Nebula flux above 250 GeV for a 50 hr observation (12% for 30 minutes). The spectral energy distribution (in the 0.03-30 TeV range) and the light curve obtained for the Crab Nebula agree with previous measurements, considering statistical and systematic uncertainties. A clear periodic signal is also detected from the pulsar at the center of the Nebula