Tablas de reducción de moneda inglesa a española y vice-versa : no comprendidas en ninguna de las obras publicadas hasta el día

Copia digital. España : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, d2024Rústica, deteriorada.Registro de la Propiedad Intelectual: Ley de 1847: 18817; n. de solicitud de ingreso: "5670"; fecha y datos de ingreso: "12 Febrero 77", "Regº fº 115 lib. 28"; firma del depositante: "Alfonso Rodero

The role of initial density profiles in simulations of coronal wave - coronal hole interaction

Interactions between global coronal waves (CWs) and coronal holes (CHs) reveal many interesting features of reflected waves and coronal hole boundaries (CHB) but have fairly been studied so far. Magnetohydrodynamic (MHD) simulations can help us to better understand what is happening during these interaction events, and therefore, to achieve a broader understanding of the parameters involved. In this study, we perform for the first time 2D MHD simulations of a CW-CH interaction including a realistic initial wave density profile that consists of an enhanced as well as a depleted wave part. We vary several initial parameters, such as the initial density amplitudes of the incoming wave, the CH density, and the CHB width, which are all based on actual measurements. We analyse the effects of different incident angles on the interaction features and we use the corresponding time-distance plots to detect specific features of the incoming and the reflected wave. We found that a particular combination of a small CH density, a realistic initial density profile and a sufficiently small incident angle leads to remarkable interaction features, such as a large density amplitude of the reflected wave with respect to the incoming one. The parameter studies in this paper provide a tool to compare time-distance plots based on observational measurements to those created from simulations and therefore enable us to derive interaction parameters from observed CW-CH interaction events that usually cannot be obtained directly. The simulation results in this study are augmented by analytical expressions for the reflection coefficient of the CW-CH interaction which allows us to verify the simulations results in an additional way. This work is the first of a series of studies aiming to finally reconstruct actual observed CW-CH interaction events by means of MHD-simulations

Role of initial density profiles in simulations of coronal wave-coronal hole interactions

[eng] Interactions between global coronal waves (CWs) and coronal holes (CHs) reveal many interesting features of reflected waves and coronal hole boundaries (CHB). However, such interactions have scarcely been studied thus far. Magnetohydrodynamic (MHD) simulations can help us to better understand what is happening during these interaction events and thus to achieve a broader understanding of the parameters involved. In this study, we performed the first 2D MHD simulations of a CW-CH interaction that include a realistic initial wave density profile consisting of an enhanced wave component as well as a depleted one. We varied several initial parameters, such as the initial density amplitudes of the incoming wave, the CH density, and the CHB width, which are all based on actual measurements. We analysed the effects of different incident angles on the interaction features and we used the corresponding time-distance plots to detect specific features of the incoming and the reflected waves. We found that the specific combination of a small CH density, a realistic initial density profile, and a sufficiently small incident angle can lead to remarkable interaction features, such as a large density amplitude for the reflected wave and greater phase speed for the reflected wave with respect to the incoming one. The parameter studies in this paper provide a tool for comparing time-distance plots based on observational measurements to those created from simulations. This has enabled us to derive interaction parameters from observed CW-CH interaction events that usually cannot be obtained directly. The simulation results in this study are augmented by analytical expressions for the reflection coefficient of the CW-CH interaction, which allows us to verify the simulations results in an complementary way. This work, with its focus on parameter studies that examine the initial density profile of CWs, is the first of a series of studies aiming to ultimately reconstruct actual observed CW-CH interaction events by means of MHD simulations. These results improve our understanding of the involved interaction parameters in a comprehensive way

Effects of different coronal hole geometries on simulations of the interaction between coronal waves and coronal holes

[eng] The geometry of a coronal hole (CH) affects the density profile of the reflected part of an incoming global coronal wave (CW). In this study, we perform for the first time magnetohydrodynamic (MHD) simulations of fast-mode MHD waves that interact with CHs of different geometries, such as circular, elliptic, convex, and concave shapes. We analysed the effect of these geometries on the density profiles of the reflected waves, and we generated the corresponding simulation-based time-distance plots. Within these time-distance plots, we determined regions that exhibit specific density features, such as large reflected density amplitudes. In a further step, these interaction features can be compared to actual observed CW–CH interaction events, which will enable us to explain interaction parameters of the observed interaction events, such as the density structure of the reflected wave. These parameters are usually difficult to understand comprehensively based on an analysis of the measurements alone. Moreover, we show that the interaction between a concave CH and CWs, whose density profile includes an enhanced as well as a depleted wave part, can lead to reflected density amplitudes that are more than twice larger than the incoming density amplitudes. Another effect of the interplay between the constructive and destructive interference of the reflected wave parts is a strongly depleted region in the middle of the CW–CH interaction process. In addition, we show that the choice of the path that is used to generate the time-distance plots is important and that this choice affects the interpretation of the CW–CH interaction results.</p

An effect of serotonergic stimulation on learning rates for rewards apparent after long intertrial intervals

Serotonin has widespread, but computationally obscure, modulatory effects on learning and cognition. Here, we studied the impact of optogenetic stimulation of dorsal raphe serotonin neurons in mice performing a non-stationary, reward-driven decision-making task. Animals showed two distinct choice strategies. Choices after short inter-trial-intervals (ITIs) depended only on the last trial outcome and followed a win-stay-lose-switch pattern. In contrast, choices after long ITIs reflected outcome history over multiple trials, as described by reinforcement learning models. We found that optogenetic stimulation during a trial significantly boosted the rate of learning that occurred due to the outcome of that trial, but these effects were only exhibited on choices after long ITIs. This suggests that serotonin neurons modulate reinforcement learning rates, and that this influence is masked by alternate, unaffected, decision mechanisms. These results provide insight into the role of serotonin in treating psychiatric disorders, particularly its modulation of neural plasticity and learning.info:eu-repo/semantics/publishedVersio

Euclid preparation: XIII. Forecasts for galaxy morphology with the Euclid Survey using deep generative models

We present a machine learning framework to simulate realistic galaxies for the Euclid Survey, producing more complex and realistic galaxies than the analytical simulations currently used in Euclid. The proposed method combines a control on galaxy shape parameters offered by analytic models with realistic surface brightness distributions learned from real Hubble Space Telescope observations by deep generative models. We simulate a galaxy field of 0.4 deg2 as it will be seen by the Euclid visible imager VIS, and we show that galaxy structural parameters are recovered to an accuracy similar to that for pure analytic Sérsic profiles. Based on these simulations, we estimate that the Euclid Wide Survey (EWS) will be able to resolve the internal morphological structure of galaxies down to a surface brightness of 22.5 mag arcsec-2, and the Euclid Deep Survey (EDS) down to 24.9 mag arcsec-2. This corresponds to approximately 250 million galaxies at the end of the mission and a 50% complete sample for stellar masses above 1010.6 M (resp. 109.6 M) at a redshift z ∼ 0.5 for the EWS (resp. EDS). The approach presented in this work can contribute to improving the preparation of future high-precision cosmological imaging surveys by allowing simulations to incorporate more realistic galaxies

Euclid: I. Overview of the Euclid mission

The current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients,dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015–2025 programme of theEuropean Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy,over about 14 000 deg² of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structureformation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range ofscience. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processingsteps, and data products. We also highlight the main science objectives and expected performance

Euclid preparation XIII. Forecasts for galaxy morphology with the Euclid Survey using deep generative models

We present a machine learning framework to simulate realistic galaxies for the Euclid Survey, producing more complex and realistic galaxies than the analytical simulations currently used in Euclid. The proposed method combines a control on galaxy shape parameters offered by analytic models with realistic surface brightness distributions learned from real Hubble Space Telescope observations by deep generative models. We simulate a galaxy field of 0.4 deg2 as it will be seen by the Euclid visible imager VIS, and we show that galaxy structural parameters are recovered to an accuracy similar to that for pure analytic Sérsic profiles. Based on these simulations, we estimate that the Euclid Wide Survey (EWS) will be able to resolve the internal morphological structure of galaxies down to a surface brightness of 22.5 mag arcsec−2, and the Euclid Deep Survey (EDS) down to 24.9 mag arcsec−2. This corresponds to approximately 250 million galaxies at the end of the mission and a 50% complete sample for stellar masses above 1010.6 M⊙ (resp. 109.6 M⊙) at a redshift z ∼ 0.5 for the EWS (resp. EDS). The approach presented in this work can contribute to improving the preparation of future high-precision cosmological imaging surveys by allowing simulations to incorporate more realistic galaxies

Euclid Quick Data Release (Q1). Extending the quest for little red dots to z<4

Recent observations with the James Webb Space Telescope (JWST) have revealed an interesting population of sources with a compact morphology and a characteristic v-shaped continuum, namely blue at a rest frame łambda<4000,Å and red at longer wavelengths. The nature of these sources, which are called little red dots (LRDs), is still highly debated because it is unclear whether they host active galactic nuclei (AGNs) and their number seems to drop drastically at z<4. We took advantage of the $63,̊m covered by the quick Euclid Quick Data Release (Q1) to extend the search for LRDs to brighter magnitudes and lower redshifts than what was possible with JWST. This is fundamental for a broader view of the evolution of this peculiar galaxy population. The selection was performed by fitting the available photometric data (Euclid, the Spitzer Infrared Array Camera (IRAC), and ground-based griz data) with two power laws to retrieve the rest-frame optical and UV slopes consistently over a wide redshift range (i.e. z<7.6). We then excluded extended objects and possible line emitters and inspected the data visually to remove any imaging artefacts. The final selection included 3341 LRD candidates from z=0.33 to z=3.6, 29 of which were also detected in IRAC. The resulting rest-frame UV luminosity function, in contrast with previous JWST studies, shows that the number density of LRD candidates increases from high redshift to z=1.5--$2.5$ and decreases at even lower redshifts. The subsample of more robust LRD candidates that are also detected with IRAC show a weaker evolution, however, which is affected by low statistics and limited by the IRAC resolution. The comparison with previous quasar UV luminosity functions shows that LRDs are not the dominant AGN population at z<4 and M_ ̊m UV <-21. Follow-up studies of these LRD candidates are pivotal to confirm their nature, probe their physical properties, and determine whether they are compatible with JWST sources because the different spatial resolution and wavelength coverage of Euclid and JWST might select different samples of compact sources