7Li in Metal-Poor Stars: The Spread of the Li Plateau

A highly homogeneous study of 23 halo field dwarf stars has achieved a Li abundance accuracy of 0.033 dex per star. The work shows that the intrinsic spread of the Li abundances of these stars at a given metallicity is <0.02 dex, and consistent with zero. That is, the Spite Li plateau for halo field dwarfs is incredibly thin. The thinness rules out depletion by more than 0.1 dex by a rotational-induced extra-mixing mechanism. Despite the thinness of the plateau, an increase of Li with [Fe/H] is seen, interpreted as evidence of Galactic chemical evolution (GCE) of Li, primarily due to Galactic cosmic ray (GCR) spallation reactions in the era of halo formation. The rate of Li evolution is concordant with: (1) observations of spallative 6Li in halo dwarfs; (2) GCE models; and (3) data on Li in higher metallicity halo stars. New data have also revealed four new ultra-Li-deficient halo dwarfs, doubling the number known. Based on their propensity to cluster at the halo main sequence turnoff and also to exist redward of the turnoff, we hypothesise that they are the products of binary mergers that ultimately will become blue stragglers. We explain their low Li abundances by normal pre-main-sequence (and possibly main-sequence) destruction in the low mass stars prior to their merging. If this explanation is correct, then such stars need no longer be considered an embarrassment to the existence of negligible Li destruction in the majority of field halo dwarfs.Comment: Proc. IAU Symp. 198, "The Light Elements and Their Evolution", L. da Silva, R. de Medeiros, & M. Spite (eds), ASP Conf. Ser. xxx (2000). 10 pages including 5 figure

Big Bang Nucleosynthesis, Population III, and Stellar Genetics in the Galactic Halo

Original article can be found at: http://www.publish.csiro.au --Copyright CSIRO --DOI : 10.1071/AS01067The diverse isotopic and elemental signatures produced in different nucle- osynthetic sites are passed on to successive generations of stars. By tracing these chemical signatures back through the stellar populations of the Galaxy, it is pos- sible to unravel its nucleosynthetic history and even to study stars which are now extinct. This review considers recent applications of ”stellar genetics” to examine the earliest episodes of nucleosynthesis in the Universe, in Population III stars and the Big Bang.Peer reviewe

In Animate Praise: The Heavenly Temple Liturgy of the Apocalypse and the Songs of the Sabbath Sacrifice

This article engages with contemporary research by drawing out evocative lines of continuity between the description of angelic praise in the heavenly realm in the Songs of the Sabbath Sacrifice, and scenes of worship in the celestial temple in the Apocalypse (especially Rev 4-5). Three aspects will be picked-out for detailed scrutiny in this comparative analysis: ● The architecture and plan of the celestial temple ● The animate praise of the celestial architecture and furnishings ● The prominence of 'seven' as a structural principle The article concludes that the celestial temple liturgy of the Apocalypse shares a wealth of conceptual parallels with the Songs of the Sabbath Sacrifice as both texts visualise the heavenly realm as the interior of a celestial temple re-imagined as a living, animate structure of praise. The 'rhapsodic' meditation on the number seven in both texts suggests that the potential liturgical context of the Apocalypse's reception (Rev 1:10, Lord's Day), analogous to the Sabbath setting of the Songs of the Sabbath Sacrifice, may merit renewed investigation

Catholic Iconography, Cultural Memory and Imaginaries: The Sacred Heart in Irish Emigrant Identity

My paper focuses on the use of images of Catholic devotional objects (rosarybeads, Sacred Heart painting) to communicate the identity of the working-class Irish emigrant in the photographic novel I Could Read the Sky (O’Grady & Pyke, 1997). I will focus on how the novel attempts to communicate a collective “cultural memory” of Irish emigrant identity to second or third generation Irish readers of the novel, as well as nuancing stereotypical images of Irish identity already contained in the “cultural imaginaries” of a wider readership. Accordingly, my paper will tease out some of the distinguishing characteristics of the concepts of “cultural memory” and “cultural imaginary” in order to highlight elements of continuity and discontinuity

Extreme Walrasian Dynamics: The Gale Example in the Lab

We study the classic Gale (1963) economy using laboratory markets. Tatonnement theory predicts prices will diverge from an equitable interior equilibrium towards infinity or zero depending only on initial prices. The inequitable equilibria determined by these dynamics give all gains from exchange to one side of the market. Our results show surprisingly strong support for these predictions. In most sessions one side of the market eventually outgains the other by more than twenty times, leaving the disadvantaged side to trade for mere pennies. We also find preliminary evidence that these dynamics are sticky, resisting exogenous interventions designed to reverse their trajectories

Sky localization of complete inspiral-merger-ringdown signals for nonspinning massive black hole binaries

We investigate the capability of LISA to measure the sky position of equal-mass, nonspinning black hole binaries, combining for the first time the entire inspiral-merger-ringdown signal, the effect of the LISA orbits, and the complete three-channel LISA response. We consider an ensemble of systems near the peak of LISA's sensitivity band, with total rest mass of 2\times10^6 M\odot, a redshift of z = 1, and randomly chosen orientations and sky positions. We find median sky localization errors of approximately \sim3 arcminutes. This is comparable to the field of view of powerful electromagnetic telescopes, such as the James Webb Space Telescope, that could be used to search for electromagnetic signals associated with merging massive black holes. We investigate the way in which parameter errors decrease with measurement time, focusing specifically on the additional information provided during the merger-ringdown segment of the signal. We find that this information improves all parameter estimates directly, rather than through diminishing correlations with any subset of well- determined parameters. Although we have employed the baseline LISA design for this study, many of our conclusions regarding the information provided by mergers will be applicable to alternative mission designs as well.Comment: 9 pages, 5 figures, submitted to Phys. Rev.