Le petit prince de Saint-Exupéry : du conte au mythe

Dans Le petit prince, l'écriture de l'âme mue le testament spirituel en parole sacrée. Par la fermeté de sa construction à l'image d'un scénario initiatique, par la qualité de son horizon métaphysique, le récit prend la forme d'une quête et véhicule une mémoire, une morale, une formation. La force du message humaniste charrié par le conte érige ainsi le mythe. Si Le petit prince semble inviter à la magie du merveilleux, cheminer avec lui impose la gravité et la profondeur du conte philosophique, et conduit ainsi à une permanente tentative de compréhension du mystère de notre existence.In The Little Prince, considered as a writing of the soul, Saint-Exupéry transforms his spiritual testament into a sacred text. Endowed with a metaphysical horizon and the structure of an initiatory quest, this story serves as a founding narrative transmitting a memory, a moral and an education. As the receptacle of a spiritual experience and of the noble humanism of its creator, the story becomes a myth. Although The Little Prince seems initially to invite us to become part of the magic of a marvellous universe, as the narrative unfolds and become more philosophical, we are enjoined to take part in a perpetual effort to understand the mystery of our own existence

High-overtone fits to numerical relativity ringdowns: beyond the dismissed n=8 special tone

In general relativity, the remnant object originating from an uncharged black hole merger is a Kerr black hole. The approach to this final state is reached through the emission of a late train of radiation known as the black hole ringdown. The ringdown morphology is described by a countably infinite set of damped sinusoids, whose complex frequencies are solely determined by the final black hole's mass and spin. Recent results advocate that ringdown waveforms from numerical relativity can be fully described from the peak of the strain onwards if quasi-normal mode models with $N_{max}=7$ overtones are used. In this work we extend this analysis to models with $N_{max}\geq 7$ up to $N_{max}=16$ overtones by exploring the parameter bias on the final mass and final spin obtained by fitting the nonprecessing binary black hole simulations from the SXS catalogue. To this aim, we have computed the spin weight $-2$ quasi-normal mode frequencies and angular separation constants for the special $(l=m=2, n=8,9)$ overtones for the Kerr spacetime. We find that a total of $N_{max}\sim 6$ overtones are on average sufficient to model the ringdown starting at the peak of the strain, although about $21\%$ of the cases studied require at least $N_{max}\sim 12$ overtones to reach a comparable accuracy on the final state parameters. Considering the waveforms from an earlier or later point in time, we find that a very similar maximum accuracy can be reached in each case, occurring at a different number of overtones $N_{max}$. We provide new error estimates for the SXS waveforms based on the extrapolation and the resolution uncertainties of the gravitational wave strain. Finally, we observe substantial instabilities on the values of the best-fit amplitudes of the tones beyond the fundamental mode and the first overtone, that, nevertheless, do not impact significantly the mass and spin estimates

Microquijotes y otros experimentos cervantinos

Pequeño ensayo sobre la pervivencia del Quijote cervantino en el microrrelato, a partir de la colección de MicroQuijotes editada por Juan Armando Epple (2005). Incluye reflexiones originales sobre Niebla, de Miguel de Unamuno, y Platero y yo, de Juan Ramón Jiménez

Los inicios narrativos de Fernando Quiñones: de la prosa costumbrista y autobiográfica a la fantasía (1948-1953)

“Los inicios narrativos de Fernando Quiñones” (1930-1998) muestra, a partir de sus colaboraciones en las revistas El Parnaso (Cádiz, 1948-1950), Platero (Cádiz, 1950-1954), Alcaraván (Arcos de la Fra., 1949-1956) y el semanario La Voz del Sur (Cádiz, 1949- 1952), cómo lo primero que escribió fueron estampas populares en prosa lírica con Juan Ramón Jiménez como modelo. A medida que sus lecturas y contactos se amplían, el tema del texto se hace más personal y más inclinado a la sobriedad del realismo. Pero en ocasiones da rienda suelta a una fantasía de tipo mayormente alegórico (lo que explica su fidelidad a Borges). En todo caso, sus constantes temáticas ya son visibles en estos primeros escritos, de los que aquí se reproducen veinte

Oscura manada intransigente : Julia Otxoa en busca de la luz

Es Julia Otxoa (San Sebastián, 1953) una poeta que desde finales de los años 70 viene mostrando una sostenida preocupación por la barbarie del ser humano: es la experiencia del siglo XX (cuyo emblema es la II Guerra Mundial) y es la experiencia del País Vasco desde la Guerra Civil, pasando por la represión franquista, hasta la democracia ensombrecida por el terrorismo. La poesía de Otxoa comienza denunciando la destrucción del amor en un lenguaje de filiación irracionalista que va desde Composición entre la luz y la sombra (1978) hasta Centauro (1989). Pero en sus últimos libros, desde La edad de los bárbaros (1997) hasta La lentitud de la luz (2008), el humanismo comprometido de su voz se abre a una reflexión esencialista en torno al sentimiento de extrañamiento, la extranjeridad como patria y destino, la comunión con la naturaleza y el entrañamiento en la infancia, y la necesidad de (re)inventar un lenguaje del silencio con el que huir de la palabrería oficial y el comercio de la mentira

Tracing the Trail of Protons through Complex I of the Mitochondrial Respiratory Chain

Mitochondria are the structures that produce the bulk part of the cellular energy currency ATP, which drives numerous energy requiring processes in the cell. This process involves a series of large enzyme complexes—the respiratory chain—that couples the transfer of electrons to the creation of a concentration gradient of protons across the inner mitochondrial membrane, which drives ATP synthesis. Complex I (or NADH-quinone oxidoreductase) is the largest and by far the most complicated of the respiratory chain enzyme complexes. The molecular mechanism whereby it couples electron transfer to proton extrusion has remained mysterious until very recently. Low-resolution X-ray structures of complex I have, surprisingly, suggested that electron transfer in the hydrophilic arm, protruding into the mitochondrial matrix, causes movement of a coupling rod that influences three putative proton pumps within the hydrophobic arm embedded in the inner mitochondrial membrane. In this Primer, we will briefly introduce the recent progress made in this area and highlight the road ahead that likely will unravel the detailed molecular mechanisms of complex I function

Fingering convection and cloudless models for cool brown dwarf atmospheres

This work aims to improve the current understanding of the atmospheres of brown dwarfs, especially cold ones with spectral type T and Y, whose modeling is a current challenge. Silicate and iron clouds are believed to disappear at the photosphere at the L/T transition, but cloudless models fail to reproduce correctly the spectra of T dwarfs, advocating for the addition of more physics, e.g. other types of clouds or internal energy transport mechanisms. We use a one-dimensional (1D) radiative/convective equilibrium code ATMO to investigate this issue. This code includes both equilibrium and out-of-equilibrium chemistry and solves consistently the PT structure. Included opacity sources are H2-H2, H2-He, H2O, CO, CO2, CH4, NH3, K, Na, and TiO, VO if they are present in the atmosphere. We show that the spectra of Y dwarfs can be accurately reproduced with a cloudless model if vertical mixing and NH3 quenching are taken into account. T dwarf spectra still have some reddening in e.g. J - H compared to cloudless models. This reddening can be reproduced by slightly reducing the temperature gradient in the atmosphere. We propose that this reduction of the stabilizing temperature gradient in these layers, leading to cooler structures, is due to the onset of fingering convection, triggered by the destabilizing impact of condensation of very thin dust.Comment: Accepted in ApJ

A uniform analysis of HD209458b Spitzer/IRAC lightcurves with Gaussian process models

We present an analysis of Spitzer/IRAC primary transit and secondary eclipse lightcurves measured for HD209458b, using Gaussian process models to marginalise over the intrapixel sensitivity variations in the 3.6 micron and 4.5 micron channels and the ramp effect in the 5.8 micron and 8.0 micron channels. The main advantage of this approach is that we can account for a broad range of degeneracies between the planet signal and systematics without actually having to specify a deterministic functional form for the latter. Our results do not confirm a previous claim of water absorption in transmission. Instead, our results are more consistent with a featureless transmission spectrum, possibly due to a cloud deck obscuring molecular absorption bands. For the emission data, our values are not consistent with the thermal inversion in the dayside atmosphere that was originally inferred from these data. Instead, we agree with another re-analysis of these same data, which concluded a non-inverted atmosphere provides a better fit. We find that a solar-abundance clear-atmosphere model without a thermal inversion underpredicts the measured emission in the 4.5 micron channel, which may suggest the atmosphere is depleted in carbon monoxide. An acceptable fit to the emission data can be achieved by assuming that the planet radiates as an isothermal blackbody with a temperature of $1484\pm 18$ K.Comment: 18 pages, 5 figures, 6 tables. Accepted by MNRA