The Pristine survey - XV. A CFHT ESPaDOnS view on the Milky Way halo and disc populations

We present a one-dimensional, local thermodynamic equilibrium homogeneous analysis of 132 stars observed at high resolution with ESPaDOnS. This represents the largest sample observed at high resolution (R ∼40 000) from the Pristine survey. This sample is based on the first version of the Pristine catalogue and covers the full range of metallicities from [Fe/H] ∼-3 to ∼+0.25, with nearly half of our sample (58 stars) composed of very metal-poor (VMP) stars ([Fe/H] ≤ -2). This wide range of metallicities provides the opportunity of a new detailed study of the Milky Way stellar population. Because it includes both dwarf and giant stars, it also enables the analysis of any potential bias induced by the Pristine selection process. Based on Gaia EDR3, the orbital analysis of this Pristine-ESPaDOnS sample shows that it is composed of 65 halo stars and 67 disc stars. After a general assessment of the sample chemical properties with the α-elements Mg and Ca, we focus on the abundance of carbon and the neutron capture elements Ba and Sr. While most of our VMP subsample is carbon normal, we also find that 14 stars out of the 38 stars with [Fe/H] ≤ -2 and measured carbon abundances turn out to be carbon-enhanced metal-poor (CEMP) stars. We show that these CEMP stars are nearly exclusively (i.e. 12 stars out of 14) in the regime of low luminosity, unevolved, dwarf stars, which we interpret as the consequence of bias of the Pristine filter against C-rich giants. Among the VMP stars, we identify two CEMP stars with no enhancement in neutron-capture process elements and another one enriched in s-process element. Finally, one VMP star is found with a very low [Sr/Fe] abundance ratio for its metallicity, as expected if it had been accreted from an ultra-faint dwarf galaxy

An appeal to the global health community for a tripartite innovation: an ‘‘Essential Diagnostics List,’’ ‘‘Health in All Policies,’’ and ‘‘See-Through 21st Century Science and Ethics"

Diagnostics spanning a wide range of new biotechnologies, including proteomics, metabolomics, and nanotechnology, are emerging as companion tests to innovative medicines. In this Opinion, we present the rationale for promulgating an ‘‘Essential Diagnostics List.’’ Additionally, we explain the ways in which adopting a vision for ‘‘Health in All Policies’’ could link essential diagnostics with robust and timely societal outcomes such as sustainable development, human rights, gender parity, and alleviation of poverty. We do so in three ways. First, we propose the need for a new, ‘‘see through’’ taxonomy for knowledge-based innovation as we transition from the material industries (e.g., textiles, plastic, cement, glass) dominant in the 20th century to the anticipated knowledge industry of the 21st century. If knowledge is the currency of the present century, then it is sensible to adopt an approach that thoroughly examines scientific knowledge, starting with the production aims, methods, quality, distribution, access, and the ends it purports to serve. Second, we explain that this knowledge trajectory focus on innovation is crucial and applicable across all sectors, including public, private, or public–private partnerships, as it underscores the fact that scientific knowledge is a co-product of technology, human values, and social systems. By making the value systems embedded in scientific design and knowledge co-production transparent, we all stand to benefit from sustainable and transparent science. Third, we appeal to the global health community to consider the necessary qualities of good governance for 21st century organizations that will embark on developing essential diagnostics. These have importance not only for science and knowledge based innovation, but also for the ways in which we can build open, healthy, and peaceful civil societies today and for future generations

Ghostly tributaries to the Milky Way: charting the halo's stellar streams with the Gaia DR2 catalogue

We present a panoramic map of the stellar streams of the Milky Way based upon astrometric and photometric measurements from the Gaia DR2 catalogue. In this first contribution, we concentrate on the halo at heliocentric distances beyond 5{ kpc}, and at Galactic latitudes |b > 30°, using the STREAMFINDER algorithm to detect structures along plausible orbits that are consistent with the Gaia proper motion measurements. We find a rich network of criss-crossing streams in the halo. Some of these structures were previously known, while several are new discoveries, but others are potentially artefacts of the Gaia scanning law and will require confirmation. With these initial discoveries, we are starting to unravel the complex formation of the halo of our Galaxy