Context. The identification of the sources that reionized the Universe and their specific contribution to this process are key missing pieces of our knowledge of the early Universe. Faint star-forming galaxies may be the main contributors to the ionizing photon budget during the epoch of reionization, but their escaping photons cannot be detected directly due to inter-galactic medium opacity. Hence, it is essential to characterize the properties of faint galaxies with significant Lyman continuum photon leakage up to z 4 to (...) define indirect indicators allowing analogues to be found at the highest redshift. Aims. Long gamma-ray bursts explode typically in star-forming regions of faint, star-forming galaxies. Through LGRB afterglow spectroscopy it is possible to detect directly LyC photons. Our aim is to use LGRBs as tools to study LyC leakage from faint, star-forming galaxies at high redshift. Methods. Here we present the observations of LyC emission in the afterglow spectra of GRB 191004B at z = 3:5055, together with those of the other two previously known LyC-emitting LGRB, to determine their LyC escape fraction and compare their properties. Results. From the afterglow spectrum of GRB 191004B we determine a neutral hydrogen column density at the LGRB redshift of og =17:2 0:15, and negligible extinction. The only metal absorption lines detected are C iv and Si iv. In contrast to GRB 050908 and GRB 060607A, the host galaxy of GRB 191004B displays significant Ly emission. From its Ly emission and the non-detection of Balmer emission lines we constrain its star-formation rate to 1 SFR 4:7 M yr. 1. We fit the Ly emission with a shell model and find parameters values consistent with the observed ones. The absolute LyC escape fractions we find for GRB 191004B, GRB 050908 and GRB 060607A are of 0:35+0:10.0:11, 0:08+0:05.0:04 and :20+0:05.0:05, respectively. We compare the LyC escape fraction of LGRBs to the values of other LyC emitters found from the literature, showing that LGRB afterglows can be powerful tools to study LyC escape for faint high-redshift star-forming galaxies. Indeed we could push LyC leakage studies to much higher absolute magnitudes. The host galaxies of the three LGRB presented here have all M1600 >.19:5 mag, with the GRB 060607A host at M1600 >.16 mag. LGRB hosts may therefore be particularly suitable for exploring the ionizing escape fraction in galaxies that are too faint or distant for conventional techniques. Furthermore the time investment is very small compared to galaxy studies. (shrink)

The World Federation of Scientific Workers (WFScW) and UNESCO share roots in the Social Relations of Science (SRS) movements and in the Franco-British scientific relations which developed in the 1930s. In this historical context (the Great Depression, the rise of Fascism and the Nazi use of science, the social and intellectual fascination for the USSR), a new model of scientific internationalism emerged, where science and politics mixed. Many progressive scientists were involved in the war efforts against Nazism, and tried to (...) prolong their international commitments into peacetime. They contributed to the establishment of the WFScW and of UNESCO in 1945–1946. Neither the WFScW nor UNESCO succeeded in achieving their initial aims. Another world emerged from the immediate post-war years, but it was not the world fancied by the progressive scientists from the mould of scientific internationalism. The aim of this article is to follow the path from the Franco-British networks towards the establishment of the WFScW and UNESCO; from an ideological scientific internationalism towards practical projects. It is to understand how these two bodies came to embody two different scientific internationalisms during the Cold War. (shrink)

We present a one per cent measurement of the cosmic distance scale from the detections of the baryon acoustic oscillations in the clustering of galaxies from the Baryon Oscillation Spectroscopic Survey, which is part of the Sloan Digital Sky Survey III. Our results come from the Data Release 11 sample, containing nearly one million galaxies and covering approximately 8500 square degrees and the redshift range 0.2 < z < 0.7. We also compare these results with those from the publicly released (...) DR9 and DR10 samples. Assuming a concordance Λ cold dark matter cosmological model, the DR11 sample covers a volume of 13 Gpc3 and is the largest region of the Universe ever surveyed at this density. We measure the correlation function and power spectrum, including density-field reconstruction of the BAO feature. The acoustic features are detected at a significance of over 7σ in both the correlation function and power spectrum. Fitting for the position of the acoustic features measures the distance relative to the sound horizon at the drag epoch, rd, which has a value of rd,fid = 149.28 Mpc in our fiducial cosmology. We find DV = at z = 0.32 and DV = at z = 0.57. At 1.0 per cent, this latter measure is the most precise distance constraint ever obtained from a galaxy survey. Separating the clustering along and transverse to the line of sight yields measurements at z = 0.57 of DA = and H =. Our measurements of the distance scale are in good agreement with previous BAO measurements and with the predictions from cosmic microwave background data for a spatially flat CDM model with a cosmological constant. © 2014 The Author Published by Oxford University Press on behalf of the Royal Astronomical Society. (shrink)

En hommage à Violaine Houdart-Merot, cet ouvrage rassemble des textes qui convergent vers une approche vivante de la littérature où l'esthétique du divers apparaît orientée par une logique de recherche, mais aussi par la ligne de force d'une réflexivité commune sur la nature des Humanités contemporaines. Ces contributions donnent ainsi le ton d'une ultime réconciliation des Anciens et des Modernes et signent l'entrée dans une ère où la considération du littéraire accepte l'expérimentation créative.

I have conducted a similar investigation on a text by a different author. The results of this investigation, which was performed on a text passage of 100,000 letters, are presented in the following tables from which one can see how and to what extent the limit theorems of the calculus of probability actually become evident.

We investigate to what extent theorems about quantum mechanical or classical entropy can be generalized to functionals of the type ρ→Tr f(ρ), or ψ→∫f(ψ)dμ, respectively, wheref is an arbitrary concave function.

Presentation of the thesis that Kumāril Bhaṭṭa and Dharmakīrti, 7th cent., Sanskrit philosophers, were Assamese by birth, contrary to the traditional belief that they are from South India.

Publikace představuje první a jediný zcela dokončený díl pamětí českého Američana, orientalisty a polyglota Aloise Richarda Nykla (1885–1958). Velmi čtivou formou se v nich věnuje svému mládí v Rakousku-Uhersku a pozdější pouti světem, např. ve Švýcarsku, Německu, USA, Mexiku, Egyptě a Japonsku. Po svém návratu do USA v roce 1916 nastoupil dráhu univerzitního profesora a později se stal světově proslulým specialistou na andaluské a srovnávací literatury. V pamětech, napsaných na počátku třicátých let minulého století, se snaží zhodnotit jak svůj život (...) i způsob, kterým nabyl své pozoruhodné jazykové znalosti přímým i teoretickým studiem po celém světě. Edice je doplněna úvodními studiemi, v nichž editor Josef Ženka zpracoval životní osudy autora. Text bohatě ilustrují unikátní fotografické a archivní materiály pocházející z pozůstalosti A. R. Nykla. (shrink)