Search

Substructures in protoplanetary disks can act as dust traps that shape the radial distribution of pebbles. By blocking the passage of pebbles, the presence of gaps in disks may have a profound effect on pebble delivery into the inner disk, crucial for the formation of inner planets via pebble accretion. This process can also affect the delivery of volatiles (such as H$_2$O) and their abundance within the water snow line region (within a few au). In this study, we aim to understand what effect the presence of gaps in the outer gas disk may have on water vapor enrichment in the inner disk. Building on previous work, we employ a volatile-inclusive multi-Myr disk evolution model that considers an evolving ice-bearing drifting dust population, sensitive to dust-traps, which loses its icy content to sublimation upon reaching the snow line. We find that vapor abundance in the inner disk is strongly affected by fragmentation velocity (v$_{\rm f}$) and turbulence, which control how intense vapor enrichment from pebble delivery is, if present, and how long it may last. Generally, for disks with low to moderate turbulence ($\alpha$ $\le$ 1 $\times$ 10$^{-3}$) and for a range of v$_{\rm f}$, radial location, and gap depth (especially that of the innermost gaps), can significantly alter enrichment. Shallow inner gaps may continuously leak material from beyond it, despite the presence of additional deep outer gaps. We finally find that the for realistic v$_{\rm f}$ ($\le$ 10 m s$^{-1}$), presence of gaps is more important than planetesimal formation beyond the snow line in regulating pebble and volatile delivery into the inner disk., Comment: 24 Pages, 15 Figures, Accepted to ApJ

Previous analyses of mid-infrared water spectra from young protoplanetary disks observed with the Spitzer-IRS found an anti-correlation between water luminosity and the millimeter dust disk radius observed with ALMA. This trend was suggested to be evidence for a fundamental process of inner disk water enrichment, used to explain properties of the Solar System 40 years ago, in which icy pebbles drift inward from the outer disk and sublimate after crossing the snowline. Previous analyses of IRS water spectra, however, were very uncertain due to the low spectral resolution that blended lines together. We present new JWST-MIRI spectra of four disks, two compact and two large with multiple radial gaps, selected to test the scenario that water vapor inside the snowline is regulated by pebble drift. The higher spectral resolving power of MIRI-MRS now yields water spectra that separate individual lines, tracing upper level energies from 900 K to 10,000 K. These spectra clearly reveal excess emission in the low-energy lines in compact disks, compared to the large disks, establishing the presence of a cooler component with $T \approx$ 170-400 K and equivalent emitting radius $R_{\rm{eq}}\approx$ 1-10 au. We interpret the cool water emission as ice sublimation and vapor diffusion near the snowline, suggesting that there is indeed a higher inwards mass flux of icy pebbles in compact disks. Observation of this process opens up multiple exciting prospects to study planet formation chemistry in inner disks with JWST., Comment: Posted as submitted to ApJ Letters; feedback and input from the community is welcome

Desde la firma del Acuerdo de Paz en noviembre de 2016, suscrito entre el gobierno de Juan Manuel Santos y el grupo insurgente de las FARC, muchas son las críticas que se han planteado desde diversos sectores políticos. Dichos cuestionamientos se enfocan, principalmente, en el aspecto institucional del Acuerdo, el cual se desarrolló a través de una amplia agenda legislativa, pero que en la práctica se evidencia limitado en mecanismos para mejorar el acceso a las víctimas al proceso de reparación. Además, se señalan problemáticas asociadas a la comunicación de las leyes y principios que orientan los procesos de reintegración y reparación a las víctimas, que limitan los procesos de difusión y acceso a la información sobre los distintos temas que interesan a la población beneficiaria de los proyectos. En el punto número 5 del Acuerdo de Paz se han establecido y orientado un conjunto de principios y medidas para encaminar las estrategias, en el marco del posconflicto, diseñadas para responder ante las diversas necesidades generadas a las víctimas en ocasión del conflicto armado, con la finalidad de promover nuevas posibilidades para la recuperación social y la reconciliación (Santa, 2013). Sin embargo, la realidad en que en la práctica estos principios han tenido que enfrentar enormes dificultades para cumplir con los principios de una atención integral y efectiva para las víctimas, ya que el Estado ha tenido problemas para garantizar el desarrollo de medidas que permitan atender oportunamente a las víctimas en un contexto complejo en el cual se sigue evidenciado la continuidad del conflicto armado. Universidad Libre – Facultad de Derecho -- Maestría en Filosofía del Derecho y Teoría Jurídica Since the signing of the Peace Agreement in November 2016, signed between the government of Juan Manuel Santos and the FARC insurgent group, there have been many criticisms that have been raised from various political sectors. These questions focus mainly, in the institutional aspect of the Agreement, which was developed through a broad legislative agenda, but in practice there is evidence of limited mechanisms to improve victims' access to the reparation process. In addition, problems associated with the communication of the laws and principles that guide the processes of reintegration and reparation to victims are pointed out, which limit the processes of dissemination and access to information on the different topics that interest the beneficiary population of the projects. . In point number 5 of the Peace Agreement, a set of principles and measures have been established and guided to direct the strategies, in the post-conflict framework, designed to respond to the diverse needs generated by the victims in occasion of the armed conflict, in order to promote new possibilities for social recovery and reconciliation (Santa, 2013). However, the reality that in practice these principles have had to face enormous difficulties in complying with the principles of comprehensive and effective care for victims, since The State has had problems guaranteeing the development of measures that allow timely attention to the victims in a complex context in which the continuity of the armed conflict continues to be evident.

The radial velocities and direct imaging observations of exoplanets have suggested that the frequency of giant planets may decrease for intermediate-mass stars ($2.5-8\,M_\odot$). The key mechanism that could hinder their formation remains unclear. From a theoretical point of view, planet formation around intermediate-mass stars may take place on longer timescales, which -- coupled with fast migration and efficient photoevaporation -- may prevent planetary formation in these environments. In this letter, we investigate the temporal evolution of the radial drift for dust particles in disks when stellar evolution is taken into account. We demonstrate that the particle drift velocity around intermediate-mass stars sharply increases after 1$-$2 Myr, potentially forming a difficult barrier to overcome in the first steps of planet formation. This high radial drift could explain the lack of disk detections around intermediate-mass stars older than 3$-$4 Myr, as opposed to low-mass stars ($, Accepted for publication in A&A (Letters). Minor changes after language edition

There are well-documented studies that demonstrate that mothers in STEM face different challenges throughout their careers, including: discrimination, drops in productivity, and inequities in wages and promotion. As a consequence, scientist-mothers are under-represented at the top most levels of academia. In addition, the Covid-19 pandemic has aggravated several of these issues in the last two years. In this talk, I will present different surveys and studies showing different barriers faced by scientist-mothers in academia. Moreover, I will present how various support policies and practices for working mothers have succeeded at retaining more mothers in different fields, and I will share my personal perspective in the field of Astronomy.

While protoplanetary disks are often treated as isolated systems in planet formation models, observations increasingly suggest that vigorous interactions between Class II disks and their environments are not rare. DO Tau is a T Tauri star that has previously been hypothesized to have undergone a close encounter with the HV Tau system. As part of the DESTINYS ESO Large Programme, we present new VLT/SPHERE polarimetric observations of DO Tau and combine them with archival HST scattered light images and ALMA observations of CO isotopologues and CS to map a network of complex structures. The SPHERE and ALMA observations show that the circumstellar disk is connected to arms extending out to several hundred au. HST and ALMA also reveal stream-like structures northeast of DO Tau, some of which are at least several thousand au long. These streams appear not to be gravitationally bound to DO Tau, and comparisons with previous Herschel far-IR observations suggest that the streams are part of a bridge-like structure connecting DO Tau and HV Tau. We also detect a fainter redshifted counterpart to a previously known blueshifted CO outflow. While some of DO Tau's complex structures could be attributed to a recent disk-disk encounter, they might be explained alternatively by interactions with remnant material from the star formation process. These panchromatic observations of DO Tau highlight the need to contextualize the evolution of Class II disks by examining processes occurring over a wide range of size scales., Comment: 42 pages, 20 figures, accepted by ApJ, reduced data available at https://zenodo.org/record/6408903 (typos from v1 fixed)

In this talk, I will present recent results from SPHERE/VLT and complementary ALMA observations of the disk around the dipper star J160421.7-213028. This is one of the brightest and most massive disk detected in the old star forming region, Upper Sco (~10Myr old). It is a transition disk, with a depleted inner cavity and a ring-like structure, which might indicate the presence of a massive planet inside the cavity. Our observations using SPHERE in 2015, allowed to detect the ring in scattered light and showed the presence of a dark dip, and of a possible secondary one. These two dark regions are thought to be due to a highly misaligned inner disk, with respect to the outer disk. In 2016 and 2017, we followed-up the disk with infrared scattered light images obtained at 9 epochs, obtaining a sample separated by days, weeks, months, and years. In our images, we clearly detect two shadows along the ring, and found that they are variable in both amplitude and morphology. This indicates that the innermost regions are highly dynamic and complex, which is likely connected to the origin of the variable, aperiodic, and dimming events obtained from the K2 light curve.

Hoy en día, los algoritmos criptográficos están presentes en prácticamente todas las aplicaciones computacionales. Normalmente pasan desapercibidos a la mayoría de usuarios pero están presentes en muchas de las operaciones que se realizan de forma cotidiana, sobre todo a través de internet, como son el almacenamiento de datos confidenciales, las comunicaciones seguras, el control de accesos o las tarjetas inteligentes (Smart cards) de las que se sirven los bancos. En multitud de ocasiones y con vistas a aumentar la velocidad de cálculo y el consumo de potencia, estos algoritmos se implementan en procesadores hardware como, por ejemplo, las citadas Smart cards. El principal problema de estas implementaciones hardware es que son susceptibles a ser vulneradas mediante los denominados ataques de fallos. En este tipo de ataques, el atacante corrompe la implementación física para modificar el estado interno del dispositivo, por ejemplo, con proyección láser sobre el chip de silicio. Gracias a este tipo de errores inducidos, el atacante puede obtener información de utilidad a través de la comparación de parejas de textos encriptados con y sin error. En concreto, el ataque busca inferir información acerca de los bits de la clave secreta que, en la criptología actual, es la máxima responsable del grado de seguridad del sistema. Este trabajo consiste en la implementación de un ataque de fallos de tipo “Differential Fault Analysis” sobre el algoritmo criptográfico más usado en la actualidad, el Advanced Encryption Standard (AES). El ataque será reproducido en simulación con el fin de determinar la viabilidad del mismo antes de llevarlo a cabo en un entorno real y físico como una FPGA (Field Programmable Gate Array), este último paso se contemplará como posible trabajo futuro. El trabajo concluirá con unos comentarios acerca de la efectividad del ataque y con una recopilación de las posibles medidas de seguridad que se podrían implementar para proteger el sistema. Nowadays, cryptographic algorithms are incorporated in practically all computational applications. Usually they are unnoticed by most of the users, but they are present in many of the operations that are performed daily, especially through the Internet, such as the storage of confidential data, secure communications, access control or the smart cards used by banks. On many occasions and to increase the calculation speed and the power consumption, these algorithms are implemented in hardware processors such as -the aforementioned- Smart cards. The main problem with these hardware implementations is that they are susceptible to being violated through fault attacks. In this type of attack, the attacker corrupts the physical implementation to modify the internal state of the device, for example, with laser projection on the silicon chip. Thanks to this type of induced errors, the attacker can obtain useful information through the comparison of pairs of texts encrypted with and without error. The attack seeks, in particular, to infer information about the bits of the secret key that, in current cryptology, is the maximum responsible for the system security. This project consists in the implementation of a fault attack so-called "Differential Fault Analysis" on the most widely used cryptographic algorithm, the Advanced Encryption Standard (AES). The attack will be reproduced in simulation in order to evaluate its feasibility before carrying it out in a real and physical environment such as an FPGA (Field Programmable Gate Array), this last step will be considered as a possible future work. The project will conclude with some comments about the effectiveness of the attack and a summary of possible security measures that could be implemented to protect the system. Universidad de Sevilla. Grado en Ingeniería de Tecnologías Industriales

We present high resolution ($0.11"\times0.06"$) 3mm ALMA observations of the highly inclined transition disk around the star T Cha. Our continuum image reveals multiple dust structures: an inner disk, a spatially resolved dust gap, and an outer ring. When fitting sky-brightness models to the real component of the 3mm visibilities, we infer that the inner emission is compact ($\le1$au in radius), the gap width is between 18-28 au, and the emission from the outer ring peaks at $\sim36$ au. We compare our ALMA image with previously published 1.6$\mu$m VLT/SPHERE imagery. This comparison reveals that the location of the outer ring is wavelength dependent. More specifically, the peak emission of the 3mm ring is at a larger radial distance than that of the 1.6$\mu$m ring, suggesting that millimeter-sized grains in the outer disk are located further away from the central star than micron-sized grains. We discuss different scenarios to explain our findings, including dead zones, star-driven photoevaporation, and planet-disk interactions. We find that the most likely origin of the dust gap is from an embedded planet, and estimate --- for a single planet scenario --- that T Cha's gap is carved by a $1.2M_{jup}$ planet., Comment: 5 pages, 3 figures, accepted for publication in MNRAS Letters

Resumen Antecedentes: los valores de la diferencia alveolo arterial de oxígeno D(A-a)O2 y de la relación presión alveolar de oxígeno y fracción inspirada de oxígeno (PaO2/FiO2), son pobremente conocidos a gran altitud para predecir ventilación mecánica (VM) en pacientes con neumonía adquirida en comunidad (NAC) mayores de 65 años. Objetivo: conocer los valores de D(A-a)O2 y PaO2/FiO2 en pacientes con NAC que requirieron soporte ventilatorio. Métodos: estudio de cohorte prospectivo donde se obtuvo la D(A-a)O2 y PaO2/FiO2 de los gases arteriales de ingreso a urgencias, con cálculo de sensibilidad (S), especificidad (E), valor predictivo positivo (VPP), valor predictivo negativo VPN) y área bajo la curva ROC para el requerimiento de VM en las primeras 72 horas. Resultados: se siguieron 247 pacientes, 37 (15%) requirieron VM, no se encontraron diferencias en edad, género, y comorbilidades entre los grupos de VM y no VM. El área bajo la curva ROC para D(A-a) O2 como predictor de VM fue de 0.84 (IC95%:0.77-0.92), para la PaO2/FiO2 de 0.85 (IC 5%: 0.78-0.92) (p

Recent powerful facilities as ALMA and VLT/SPHERE, with their unprecedented sensitivity and spatial resolution, have revealed fascinating structures in protoplanetary disks at different wavelengths, such as: multiple rings, vortices, asymmetries, dips, and spiral arms. In this talk, I will compare these observations with theoretical models that combine hydrodynamical simulations of gas evolution and dust growth, which include the coagulation and fragmentation of particles. I will present how these detailed observations are providing significant insights about different parameters that play an important role in the evolution of protoplanetary disks such as snow lines, potential embedded planets, and viscosity.

Tesis (Cirujano Dentista) La pulpa dental es un tejido conectivo laxo, conformado por células, fibras y matriz extracelular, que forma parte del complejo dentino-pulpar. Este complejo está expuesto a distintos tipos de injuria, respondiendo a éstas a través de un proceso inflamatorio. En Chile, según el MINSAL, la caries dental tiene una prevalencia cercana al 100% en los adultos, por lo que es posible suponer que el odontológo se verá enfrentado a un alto número de pacientes que padezcan diversos grados de inflamación pulpar. Es por esto que, a través de esta revisión, queremos que el lector comprenda la estructura y fisiología del complejo dentino-pulpar para que así también pueda comprender la patología y capacidad reparativa de la pulpa. Con este objeto, se realizó una revisión de artículos originales de manera manual y electrónica a través de las bases de datos PubMed/Medline y EBSCOhost; la cual fue complementada con una búsqueda manual utilizando como fuente de bibliografía convencional los libros, revistas y tesis presentes en las bibliotecas de la Universidad Andrés Bello, Universidad de Valparaíso, Universidad Finis Terrae, Universidad Mayor y Universidad de Chile. Con esta búsqueda se seleccionaron, de acuerdo a los criterios de inclusión y exclusión, 58 artículos originales, 22 libros y 5 tesis.El conocimiento de la estructura y fisiología del complejo dentino-pulpar, permite comprender la patogenia de la enfermedad pulpar, la cual se basa en procesos inflamatorios de carácter crónico y agudo, siendo el primero el más frecuente. Existen diversos grados de pulpitis, que se pueden clasificar dependiendo de su reversibilidad o irreversibilidad. Si el estímulo no sobrepasa el umbral de tolerancia fisiológica pulpar, y éste es correctamente removido, la pulpa tiene la capacidad de reparar, incluso en condiciones de exposición por caries siempre que las condiciones sean favorables.

Transitional disks represent a short stage of the evolution of circumstellar material. Studies of dust grains in these objects can provide pivotal information on the mechanisms of planet formation. Dissimilarities in the spatial distribution of small (micron-size) and large (millimeter-size) dust grains have recently been pointed out. Constraints on the small dust grains can be obtained by imaging the distribution of scattered light at near-infrared wavelengths. We aim at resolving structures in the surface layer of transitional disks (with particular emphasis on the inner 10 - 50 AU), thus increasing the scarce sample of high resolution images of these objects. We obtained VLT/NACO near-IR high-resolution polarimetric differential imaging observations of SAO 206462 (HD135344B). This technique allows one to image the polarized scattered light from the disk without any occulting mask and to reach an inner working angle of 0.1''. A face-on disk is detected in H and Ks bands between 0.1'' and 0.9''. No significant differences are seen between the H and Ks images. In addition to the spiral arms, these new data allow us to resolve for the first time an inner cavity for small dust grains. The cavity size (about 28 AU) is much smaller than what is inferred for large dust grains from (sub)mm observations (39 to 50 AU). The interaction between the disk and potential orbiting companion(s) can explain both the spiral arm structure and the discrepant cavity sizes for small and large dust grains. One planet may be carving out the gas (and, thus, the small grains) at 28 AU, and generating a pressure bump at larger radii (39 AU), which holds back the large grains. We analytically estimate that, in this scenario, a single giant planet (with a mass between 5 and 15 Jupiter masses) at 17 to 20 AU from the star is consistent with the observed cavity sizes., Comment: 11 pages, 6 figures; accepted for publication in A&A

The detection of a wide range of substructures such as rings, cavities, and spirals has become a common outcome of high spatial resolution imaging of protoplanetary disks, both in the near-infrared scattered light and in the thermal millimetre continuum emission. The most frequent interpretation of their origin is the presence of planetary-mass companions perturbing the gas and dust distribution in the disk (perturbers), but so far the only bona fide detection has been the two giant planets carving the disk around PDS 70. Here, we present a sample of 15 protoplanetary disks showing substructures in SPHERE scattered-light images and a homogeneous derivation of planet detection limits in these systems. To obtain mass limits we rely on different post-formation luminosity models based on distinct formation conditions, which are critical in the first million years of evolution. We also estimate the mass of these perturbers through a Hill radius prescription and a comparison to ALMA data. Assuming that one single planet carves each substructure in scattered light, we find that more massive perturbers are needed to create gaps within cavities than rings, and that we might be close to a detection in the cavities of RX J1604.3-2130A, RX J1615.3-3255, Sz Cha, HD 135344B, and HD 34282. We reach typical mass limits in these cavities of 3-10 M-Jup. For planets in the gaps between rings, we find that the detection limits of SPHERE high-contrast imaging are about an order of magnitude away in mass, and that the gaps of PDS 66 and HD 97048 seem to be the most promising structures for planet searches. The proposed presence of massive planets causing spiral features in HD 135344B and HD 36112 are also within SPHERE's reach assuming hot-start models. These results suggest that the current detection limits are able to detect hot-start planets in cavities, under the assumption that they are formed by a single perturber located at the centre of the cavity. More realistic planet mass constraints would help to clarify whether this is actually the case, which might indicate that perturbers are not the only way of creating substructures., Astronomy & Astrophysics, 652, ISSN:0004-6361, ISSN:1432-0746