Institute of Astronomy and Space Physics

A bstract We study spacetime four-point functions of chiral primary operators for superstrings propagating in AdS 3 × S 3 × T 4 from the worldsheet perspective, allowing for external states with arbitrary spectral flow charges. We work at small boundary cross-ratio and consider both extremal (supersymmetry-protected) and non-extremal configurations. The string correlators involve a non-trivial integration over the worldsheet moduli, and we demonstrate how the exchange of short and long strings is encoded in distinct integration regions. We interpret our results in terms of the operator product expansion in the boundary theory, and make explicit the precise matching with the available data for the relevant holographic correlators.

En este artículo me propongo indagar en los alcances de la limitación de la responsabilidad en Levinas como la operación que —siguiendo la sugerencia de Miguel Abensour— hace posible el pasaje de la ética a la política en su obra y permite pensar el vínculo comunitario. A tal fin, entiendo que algunas figuras de la alteridad que aparecen descriptas en la literatura de Mariana Enríquez permiten reflexionar sobre la complejidad de la responsabilidad en una comunidad que se pretenda inclusiva.

Hydroclimatic extremes are intensifying, escalating risks to ecosystems, infrastructure, and vulnerable communities. Rapid technological innovation and scientific discovery offer powerful tools to address these challenges, yet a gap remains between hydroclimate knowledge production and its use in decision-making. Bridging this divide requires democratizing hydroclimate science through expanded participation in research design and implementation, as well as in the distribution of recognition, resources, and decision power. Democratizing science can foster outcomes that are (1) more credible, through transparency and integration of decision-maker perspectives; (2) more just, through fair distribution of research opportunities, resources, recognition, and decision power; and (3) more resilient, by strengthening the capacity of communities and institutions to adapt, learn, and recover from climate pressures. Drawing on insights from the 2024 Global Energy and Water EXchanges (GEWEX) Early Career Researcher Workshop, which gathered participants from 19 countries and across disciplines, we outline pathways toward more democratic hydroclimate science grounded in diverse participation and shared leadership. We highlight three priorities: building trust through co-production, improving the usability of hydroclimate information, and promoting ethical use of emerging technologies. Case studies illustrate how early- and mid-career researchers and practitioners are advancing these priorities and modeling practices that connect innovation with equity. Achieving lasting and effective change requires research and funding institutions to recognize and support collaborative leadership, and to value relevance and accountability alongside technical excellence. Strengthening such democratic frameworks can help ensure that hydroclimate science advances more just research practices and supports the resilience of the communities it serves.

En medio de las abruptas reconfiguraciones del mundo conocido que se evidencian en el actual ciclo histórico, signado por los avances electorales de la ultraderecha y el creciente estado de guerra y genocidio a nivel global, ante un mundo en el que las palabras y la formas de la acción política que veníamos usando históricamente para imaginar posibilidades emancipatorias aparecen arrebatadas, apropiadas, vaciadas o denigradas, no espero (ni puedo) ocupar el gesto ampuloso de proponer un abordaje teórico sobre incipientes, frágiles formas de resistencia pero sí quizá prefiera ensayar un acotado ejercicio personal de escritura que dé cuenta de los hechos y también de los debates que nos atraviesan y ojalá alimente una potencial bitácora colectiva. Me propongo compartir aquí el trayecto vertiginoso de una experiencia política que irrumpió en la Argentina en los primeros meses de 2025 de manera inesperada y desafiante, por fuera de las lógicas y las organizaciones conocidas (sindicatos, partidos políticos, federaciones de la comunidad LGTBINBQ+) y que se expresó de manera patente en la multitudinaria manifestación del 1º de febrero (1F) en Buenos Aires y en cientos de ciudades y pueblos de Argentina y otras ciudades del mundo, estimándose en total la movilización de dos millones de personas aquel día. Comparto una serie de apuntes escritos en primera persona del singular en tanto partícipe-testigo directa de este proceso, en diálogo polifónico con testimonios y análisis escritos por otras personas implicadas. Aspiro a dar cuenta de las coordenadas de su vertiginosa gestación, el carácter de acontecimiento público que alcanzó, y también los límites y conflictos que están haciendo mella muy pronto de esta excepcional experiencia. Esta crónica personal se sabe escrita en medio de la urgencia, sin distancia ni calma. Estamos anonadades y dañades por la magnitud y la virulencia de los ataques que estamos recibiendo. Pero a la vez, en medio de este tiempo atroz, a pesar de todo, no dejamos de inventar colectivamente modos de confrontar ante tamaña escalada de odio y sostener la posibilidad de vidas disidentes.

The photophysical behavior of novel UV-MALDI matrices belonging to the family of hydroxy-nitrobenzoic acids (HNBAs) was investigated in both acetonitrile and methanol solutions, as well as in the solid state, using spectroscopic, luminescence, and photoacoustic techniques. The study focused on the following positional isomers: 2-hydroxy-3-nitrobenzoic acid, 2-hydroxy-4-nitrobenzoic acid, 2-hydroxy-5-nitrobenzoic acid, 3-hydroxy-2-nitrobenzoic acid, 3-hydroxy-4-nitrobenzoicacid, 3-hydroxy-5-nitrobenzoic acid, 4-hydroxy-3-nitrobenzoic acid, and 5-hydroxy-2-nitrobenzoic acid. Most isomers exhibited strong solid-state absorption at the excitation wavelengths commonly used in UV-MALDI technique (>90% at 337 and 355 nm), high photostability, no detectable luminescence, and highly efficient excitation energy dissipation as prompt heat, resembling the behavior of calorimetric references under both N2- and air-saturated conditions, suggesting a potential role in facilitating desorption/ionization processes in UV-MALDI. These findings provide valuable insight into the performance of HNBAs as matrix candidates.

Este trabajo aborda el análisis faunístico en contextos pastoriles andinos a través del estudio de dos sitios arqueológicos: Montículo Chávez (Antofagasta de la Sierra, Catamarca) y Chiu Chiu-200 (Río Loa, Chile). Se proponen modelos de trozamiento basados en datos etnográficos y se aplican índices de utilidad anatómica para evaluar las prácticas de procesamiento, consumo y manufactura de charqui. Los resultados indican diferencias en las estrategias de aprovechamiento óseo, vinculadas a factores logísticos, movilidad estacional y posible caza de camélidos silvestres junto con la crianza de rebaños domésticos. Se destaca la necesidad de distinguir entre fauna doméstica y silvestre en el registro, así como de considerar la variabilidad funcional de los sitios dentro de los sistemas de asentamiento pastoril.

The knowledge of mechanical properties of materials is based on a precise analysis of their relaxation spectra. The development of methods to deconvolve spectra from measured data, and the assessment of their reliability, is therefore of paramount importance. We present a novel Bayesian deconvolution method based on a physically grounded parameterization of the spectra. We use a Metropolis-Hastings Markov-chain Monte Carlo fitting algorithm, with a full posterior analysis to obtain the best-fitting spectrum and its uncertainties. We test its performance on simulated data, finding that it is unbiased, reliable, and gives precise results even under strong noise.

Context. Bulges, located at the central regions of galaxies, are complex structures, expected to be shaped by the physical processes involved in the assembly history of their host galaxy, such as gravitational collapse, mergers, interactions, and bars. As a consequence, a variety of bulges with distinct morphologies and chemistry could be produced. Aim. We aim to explore the existence of a stellar mass-metallicity relation of bulges and analyze the possible imprint of distinctive features by accretion and migration of stars, which could store information in their assembly histories. Methods. We used 44 central galaxies from the ̧ielo cosmological simulations. Their stellar masses are within the range of ∼ M_⊙. We decomposed the galaxy into bulge and disk using the circularity and binding energies. We tracked the stellar populations in bulges back in time to their birth locations, classifying them as bulge- and disk-born, in-situ, and accreted. Results. We find that most of the stars in our bulges are formed in-situ, but 33% of our bulges show a non-negligible contribution of stellar accretion from satellites, which could add to about 35% of the population. The accreted material is generally contributed by two or three satellites at most. In some bulges, we also find up to 32% of stars that migrated from the disk due to secular evolution, with a median of 10%. Regardless of the formation histories, we find a clear for bulges, which is more enriched by about 0.4 dex than the corresponding relation of the disk components, and about 0.15 dex more enriched than the galaxy We find evidence that the dispersion in the bulge is influenced by both stellar accretion from satellites and migration from the disk, such that, at a fixed bulge mass, bulges with higher fractions of accreted and migrated stars tend to be less metal-rich. Therefore, we find a for bulges, which is consistent with an increase in metallicity with increasing mass, while its dispersion stores information on the contribution from different formation channels.

This paper aims to describe the rationale of forest Above Ground Biomass (AGB) and related Aboveground Carbon Stock (ACS) products developed with satellite remote sensing. Optical and radar imagery were synergistically combined to (1) build a classification map of vegetation species; (2) build a regression of cross-polarized, angle-normalized radar backscattering coefficient ($\gamma_{H V}^{0}$) with ground surveys for each class; (3) apply the corresponding regressions to the entire vegetation class map to retrieve AGB and ACS. The scope of these products is focused on two of Argentina’s most densely forested provinces: Misiones in the northwestermost part and Chubut in the south. The classes involve native (tropical and temperate) and implanted forests and the ground survey sampled homogeneous stands of each, totalizing 193 data measurements of AGB. ACS was derived from AGB using published dasometric relations on a species-basis. The output of each product consists of five layers, three of which define the lower and upper limits of an 80% confidence level interval and its median value. The other two are ancillary layers. The products are freely available online at the National Commission on Space Activities (CONAE) website [1].