The Most Metal-Poor Stars. V. The CEMP-no Stars in 3D and Non-LTE

We explore the nature of carbon-rich ([C/Fe]_{1D,LTE} > +0.7), metal-poor ([Fe/H_{1D,LTE}] < -2.0) stars in the light of post 1D,LTE literature analyses, which provide 3D-1D and NLTE-LTE corrections for iron, and 3D-1D corrections for carbon (from the CH G-band, the only indicator at lowest [Fe/H]). High-excitation C~I lines are used to constrain 3D,NLTE corrections of G-band analyses. Corrections to the 1D,LTE compilations of Yoon et al. and Yong et al. yield 3D,LTE and 3D,NLTE Fe and C abundances. The number of CEMP-no stars in the Yoon et al. compilation (plus eight others) decreases from 130 (1D,LTE) to 68 (3D,LTE) and 35 (3D,NLTE). For stars with -4.5 < [Fe/H] < -3.0 in the compilation of Yong et al., the corresponding CEMP-no fractions change from 0.30 to 0.15 and 0.12, respectively. We present a toy model of the coalescence of pre-stellar clouds of the two populations that followed chemical enrichment by the first zero-heavy-element stars: the C-rich, hyper-metal-poor and the C-normal, very-metal-poor populations. The model provides a reasonable first-order explanation of the distribution of the 1D,LTE abundances of CEMP-no stars in the A(C) and [C/Fe] vs. [Fe/H] planes, in the range -4.0 < [Fe/H] < -2.0. The Yoon et al. CEMP Group I contains a subset of 19 CEMP-no stars (14% of the group), 4/9 of which are binary, and which have large [Sr/Ba]_{1D,LTE} values. The data support the conjectures of Hansen et al. (2016b, 2019) and Arentsen et al. (2018) that these stars may have experienced enrichment from AGB stars and/or "spinstars".Comment: ApJ in pres

Heavy metals and nitrogen in mosses: spatial patterns in 2010/2011 and long-term temporal trends in Europe

Naturally-occurring mosses have been sampled across Europe to monitor the deposition of heavy metals and nitrogen from the air. This survey has been repeated at five-yearly intervals since 1990 for heavy metals and since 2005 for nitrogen. In 2010/2011, mosses were collected at ca. 4,500 sites in 25 countries for heavy metals and ca. 2,400 sites in 15 countries for nitrogen. In general, the lowest concentrations in mosses were found in northern Europe for both heavy metals and nitrogen. The highest concentrations of heavy metals were often observed in south-eastern Europe, whereas the highest concentrations of nitrogen were found in parts of western and central Europe. Europe-wide the concentration of lead (77% decline), vanadium (57%), iron (52%) and cadmium (51%) has declined the most since 1990, whereas the concentration of copper has declined the least (11% decline). Since 1995, the concentration of arsenic and mercury has declined by 26% and 23% respectively. The nitrogen concentration in mosses has hardly changed since 2005

Transformation techniques for the parameter estimation of discrete-time transfer functions

Imperial Users onl

Writing about war: making sense of the absurd in Mileta Prodanović's novel Pleši, čudovište, na moju nežnu muziku (Dance, you monster, to my soft music)

In the narrative of a mass conflict, the human experience of its effects may be subsumed into the rationalizing contours of history, or they may fall completely outside our comprehension. This article examines the intertextual strategies employed in Prodanović's novel about the war in former Yugoslavia. The text conveys the reality of the conflict by relating it through events and characters located in prior media constructions. The historical, documentary, mythic, and fictional sources focus on the signifying systems which drag the war into the horizon of expectations of those who were not there, closing the gap between reality and representation, life and art