Non-LTE aluminium abundances in late-type stars

Aluminium plays a key role in studies of the chemical enrichment of the Galaxy and of globular clusters. However, strong deviations from LTE (non-LTE) are known to significantly affect the inferred abundances in giant and metal-poor stars. We present NLTE modeling of aluminium using recent and accurate atomic data, in particular utilizing new transition rates for collisions with hydrogen atoms, without the need for any astrophysically calibrated parameters. For the first time, we perform 3D NLTE modeling of aluminium lines in the solar spectrum. We also compute and make available extensive grids of abundance corrections for lines in the optical and near-infrared using one-dimensional model atmospheres, and apply grids of precomputed departure coefficients to direct line synthesis for a set of benchmark stars with accurately known stellar parameters. Our 3D NLTE modeling of the solar spectrum reproduces observed center-to-limb variations in the solar spectrum of the 7835 {\AA} line as well as the mid-infrared photospheric emission line at 12.33 micron. We infer a 3D NLTE solar photospheric abundance of A(Al) = 6.43+-0.03, in exact agreement with the meteoritic abundance. We find that abundance corrections vary rapidly with stellar parameters; for the 3961 {\AA} resonance line, corrections are positive and may be as large as +1 dex, while corrections for subordinate lines generally have positive sign for warm stars but negative for cool stars. Our modeling reproduces the observed line profiles of benchmark K-giants, and we find abundance corrections as large as -0.3 dex for Arcturus. Our analyses of four metal-poor benchmark stars yield consistent abundances between the 3961 {\AA} resonance line and lines in the UV, optical and near-infrared regions. Finally, we discuss implications for the galactic chemical evolution of aluminium.Comment: 20 pages, 15 figures. Accepted for publication in A&

Valuing Easements: Some Experimental Evidence

Trefzger and Munneke (1998) present a theoretical model, where the surplus that an easement gives rise to will be split equally between the parties. We provide experimental evidence from Sweden indicating that the split of the surplus depends on the context and what is judged to be reasonable principles of a fair distribution. The dominant estates got a significantly higher share of the surplus because they could start the bargaining with a bid that only included compensation for cost, whereas the servient estate could not find any principle that would give them the whole surplus. After these initial asymmetric bids, the parties usually met halfway.

Exploring the production and depletion of lithium in the Milky Way stellar disk

[ABRIDGED] We determine Li abundances for a well-studied sample of 714 F and G dwarf, turn-off, and subgiant stars in the solar neighbourhood. The analysis is based on line synthesis of the Li line at 6707 {\AA} in high-resolution and high signal-to-noise ratio echelle spectra, obtained with the MIKE, FEROS, SOFIN, UVES, and FIES spectrographs. The presented Li abundances are corrected for non-LTE effects. Out of the sample of 714 stars we are able to determine Li abundances for 420 stars and upper limits on the Li abundance for another 121 stars. 18 of the stars with well-determined Li abundances are listed as exoplanet host stars. Our main finding is that there are no signatures of Li production in the thick disk, but the Li abundance for stars of the same effective temperature is independent of metallicity for stars that can be associated with the Galactic thick disk. Significant Li production is however seen in the thin disk, with a steady increase towards super-solar metallicities. At the highest metallicities, however, around [Fe/H]~ +0.3, we tentatively confirm the recent discovery that the Li abundances level out. We hence contradict the recent finding in other studies that found that Li is also produced in the thick disk. This is likely due to the chemically defined selection criteria those studies used to define their thick disk samples. Age criteria that we use here, produce a thick disk stellar sample that is much less contaminated by thin disk stars, and hence more reliable abundance trends. [ABRIDGED] A conclusion that can be drawn is that no significant Li production, relative to the primordial abundance, took place during the first few billion years of the Milky Way, an era coinciding with the formation and evolution of the thick disk. [ABRIDGED]Comment: Accepted for publication in A&

Compulsory Purchase – Reasonable and Fair Compensation

Swedish law provides that compensation for compulsory purchase – in some cases – shall be decided according to the following general principle: The compensation should correspond to the price that could have been expected if it had been a "normal voluntary transaction". However, in those specific situations where compulsory purchase applies, there is always a lack of empirical data of price levels in voluntary agreements. In this article we enlighten the problem through bargaining experiments with buyers and sellers. We provide experimental evidence from Sweden indicating that the price level – or the profit-sharing between buyer and seller – depends on the context and what is judged to be reasonable principles of fair distribution

EU-Pacific Climate Change Policy and Engagement : a Social Science and Humanities review

Report for EU Framework 7 funded ECOPAS (European Consortium for Pacific Studies), Deliverable D3.311, 2013.This short report provides an overview and review of EU-Pacific Climate Change Policy and Engagement from a Social Science and Humanities perspective. Alongside an outline of the historical background and contemporary mechanisms that frame EU- Pacific partnership relations in reference to climate change, this report provides an outline of the SSH research literature produced in respect of Pacific peoples responses to climate change, and across the academy more generally. Finally, this report provides a commentary on the characteristics of current discourses carried by policy and engagement, and an analysis of the distinctive features that the SSH perspective reveals and which emerge from a close understanding of Pacific peoples’ own concerns. The review suggests how EU-Pacific engagement might draw upon SSH research evidence and methods to better approach these emerging policy concerns.Othe

Structure of TAR RNA Complexed with a Tat-TAR Interaction Nanomolar Inhibitor that Was Identified by Computational Screening

AbstractHIV-1 TAR RNA functions critically in viral replication by binding the transactivating regulatory protein Tat. We recently identified several compounds that experimentally inhibit the Tat-TAR interaction completely at a 100 nM concentration. We used computational screening of the 181,000-compound Available Chemicals Directory against the three-dimensional structure of TAR [1]. Here we report the NMR-derived structure of TAR complexed with acetylpromazine. This structure represents a new class of compounds with good bioavailability and low toxicity that bind with high affinity to TAR. NMR data unambiguously show that acetylpromazine binds only to the unique 5′ bulge site to which the Tat protein binds. Specificity and affinity of binding are conferred primarily by a network of base stacking and hydrophobic interactions. Acetylpromazine alters the structure of free TAR less than Tat peptides and neomycin do

A method for identifying metal-poor stars with Gaia BP/RP spectra

Context. The study of the oldest and most metal-poor stars in our Galaxy promotes our understanding of the Galactic chemical evolution and the beginning of Galaxy and star formation. However, they are notoriously difficult to find, with only five stars at $\mathrm{[Fe/H]<-5.0}$ having been detected to date. Thus, the spectrophotometric data of 219 million sources which became available in the third Gaia Data Release comprise a very promising dataset for the identification of metal-poor stars. Aims. We want to use the low-resolution Gaia Blue Photometer / Red Photometer (BP/RP) spectra to identify metal-poor stars. Our primary aspiration is to help populate the poorly constrained tail of the metallicity distribution function of the stellar halo of the Galaxy. Methods. We developed a metal-poor candidate selection method based on flux ratios from the BP/RP Gaia spectra, using simulated synthetic spectra. Results. We found a relation between the relative iron abundance and the flux ratio of the Ca H \& K region to that of the $\mathrm{H\beta}$ line. This relation is temperature and surface gravity dependent, and it holds for stars with $\mathrm{4800\,K \leq T_{eff}\leq6300\,K}$. We applied it to noisy simulated synthetic spectra and inferred $\mathrm{[Fe/H]}$ with an uncertainty of $\sigma_{\mathrm{[Fe/H]}}\lessapprox0.65$ dex for $\mathrm{-3\leq[Fe/H]}\leq 0.5$ and G=15-17mag, which is sufficient to identify stars at $\mathrm{[Fe/H]<-2.0 }$ reliably. We predict that by selecting stars with inferred $\mathrm{[Fe/H]}\leq-2.5$ dex, we can retrieve 80% of the stars with $\mathrm{[Fe/H]}\leq-3$ and have a success rate of about 50%, that is one in two stars we select would have $\mathrm{[Fe/H]}\leq-3$. We do not take into account the effect of reddening, so our method should only be applied to stars which are located in regions of low extinction.Comment: 11 pages, 15 figures, to be published in A&

European Union development strategy in the Pacific

Study Report for the European Parliament Development Committee, undertaken by ECOPAS (European Consortium for Pacific Studies).Development in the Pacific region is uneven, multi-layered and challenging. The European Union’s development cooperation with the Pacific is significant; in fact the EU is the second largest donor of development assistance to the region. This study, implemented by the European Consortium for Pacific Studies, analyses the current and future contexts for European Union engagement in development cooperation with the Pacific, and proposes elements of a renewed EU development strategy for the region. From a Pacific perspective, the question of defining a new EU development strategy is as much a matter of defining new and equal partnerships through which Pacific development strategies can be supported. Rising to the challenge of re-imagining EU-Pacific relations will require a good deal of work and reflection. The Pacific clearly constitutes a geopolitical context whose importance is markedly set to grow in significance, and there is a clear rationale for the EU to commit further resources to support its interests and activities in the region. In particular, the EU should enhance and deepen its institutional knowledge and means of drawing upon existing expertise on ‘Pacific Ways’.Publisher PD

A Longitudinal, Mixed-Method Study of the Identity Theory of Desistance

Recently, Paternoster and Bushway (2009) developed the Identity Theory of Desistance to explain how once criminal offenders transform their identities and reform. In an effort to test important components of this theory, the current study analyzed retrospective narratives from 144 substance-involved, male offenders from Delaware. After coding the narratives for mention of concepts from the identity theory and other theories of desistance, the author conducted time-based and age-based group-based trajectory models and multinomial logistic regression analyses to test whether the identity theory could explain criminal desistance. Results suggest that many offenders undergo these processes, and there may be experiences that distinguish those who desist from those who persist in crime and drug use. These include the formation of hoped-for selves, a change in preferences, social networks, and routine activities, motivation to change, and treatment