F-theory at order α′3\alpha'^3

We study the effective physics of F-theory at order $\alpha'^3$ in derivative expansion. We show that the ten-dimensional type IIB eight-derivative couplings involving the graviton and the axio-dilaton naturally descend from pure gravity in twelve dimensions. Upon compactification on elliptically fibered Calabi-Yau fourfolds, the non-trivial vacuum profile for the axio-dilaton leads to a new, genuinely N=1, $\alpha'^3$ correction to the four-dimensional effective action.Comment: 24 pages, minor improvements, typos correcte

A sequence of nitrogen-rich very red giants in the globular cluster NGC 1851

We present the abundances of N in a sample of 62 stars on the red giant branch (RGB) in the peculiar globular cluster NGC 1851. The values of [N/Fe] ratio were obtained by comparing the flux measured in the observed spectra with that from synthetic spectra for up to about 15 features of CN. This is the first time that N abundances are obtained for such a large sample of RGB stars from medium-resolution spectroscopy in this cluster. With these abundances we provide a chemical tagging of the split red giant branch found from several studies in NGC 1851. The secondary, reddest sequence on the RGB is populated almost exclusively by N-rich stars, confirming our previous suggestion based on Stromgren magnitudes and colours. These giants are also, on average, enriched in s-process elements such as Ba, and are likely the results of pollution from low mass stars that experienced episodes of third dredge-up in the asymptotic giant branch phase.Comment: Version to match the one in press on Astronomy and Astrophysic

Selfish Dark Matter

We present a mechanism where a particle asymmetry in one sector is used to generate an asymmetry in another sector. The two sectors are not coupled through particle number violating interactions and are not required to be in thermal contact with each other. When this mechanism is applied to baryogenesis in asymmetric dark matter models, we find that the dark matter particles can be extremely light, e.g. much lighter than an eV, and that in some cases there is no need to annihilate away the symmetric component of dark matter. We discuss a concrete realization of the mechanism with signals in direct detection, at the LHC, at $B$-factories or future beam dump experiments.Comment: 18+5 pages, 2 figures; Journal version: Added references, small changes to the free-streaming length estimate

Influence of zinc on distiller’s yeast:cellular accumulation of zinc and impact on spirit congeners

Accumulation of zinc by a whisky distilling yeast strain of Saccharomyces cerevisiae was studied during fermentation of malt wort and synthetic defined medium. Zinc uptake by yeast cells was very rapid in malt wort, as zinc (0.32 μg/mL) was completely removed from the fermentation medium within one hour. The type of fermentable carbohydrate had an impact on the kinetics of zinc accumulation, with maltose most effective at enhancing metal uptake at zinc concentrations above 3.2 μg/mL. Enriching yeast cells with zinc by “preconditioning” impacted on the production of flavour congeners in the distillates produced from fermented cultures. Such distillates were characterized by an altered flavour and aroma profile. In particular, the production of some higher alcohols increased when yeast cells were preconditioned with zinc. This phenomenon is yeast strain related. Industrial fermentation processes, including brewing and distilling, may benefit from optimization of zinc bioavailability in yeast cultures resulting in more efficient fermentations and improved product quality

Developing Capacity, Skills, and Tobacco Control Networks to address Tobacco-related Disparities: Leadership and Advocacy Institute to Advance Minnesota’s Parity for Priority Populations (LAAMPP)

Priority populations disproportionately experience tobacco-related disparities, despite population level declines in tobacco use. The Leadership and Advocacy Institute to Advance Minnesota’s Parity for Priority Populations (LAAMPP) recruits and trains African immigrants/African Americans, Asian Americans/Pacific Islanders, American Indians, Chicano/Latinos, and LGBTQ community members to develop leaders to address tobacco harms in their communities. This paper describes and evaluates the LAAMPP Institute, and discusses lessons learned through the Institute and future directions for community-based tobacco-control efforts. The mixed-methods evaluation included qualitative key informant interviews with LAAMPP Fellows and community and project contacts, a Skills Assessment Tool, project case studies, and a social network analysis of the Fellows’ tobacco-control social networks at baseline and follow-up. At follow-up, Fellows’ tobacco control networks were larger, more extensive and diverse, and included more actors perceived to be influential in tobacco control. Fellows’ skills increased in core competencies (tobacco control, advocacy, facilitation, collaboration, cultural/community competence) and Fellows used tobacco, advocacy and cultural/community competencies more frequently. Four of five cohorts successfully passed policies. The results of LAAMPP suggest that a cross-cultural leadership institute contributes to the successful development of capacity and leadership skills among priority populations and may be a useful model for others working toward health equity

Terzan 8: a Sagittarius-flavoured globular cluster

Massive globular clusters (GCs) contain at least two generations of stars with slightly different ages and clearly distinct light elements abundances. The Na-O anticorrelation is the best studied chemical signature of multiple stellar generations. Low-mass clusters appear instead to be usually chemically homogeneous. We are investigating low-mass GCs to understand what is the lower mass limit where multiple populations can form, mainly using the Na and O abundance distribution. We used VLT/FLAMES spectra of giants in the low-mass, metal-poor GC Terzan 8, belonging to the Sagittarius dwarf galaxy, to determine abundances of Fe, O, Na, alpha-, Fe-peak, and neutron-capture elements in six stars observed with UVES and 14 observed with GIRAFFE. The average metallicity is [Fe/H]=-2.27+/-0.03 (rms=0.08), based on the six high-resolution UVES spectra. Only one star, observed with GIRAFFE, shows an enhanced abundance of Na and we tentatively assign it to the second generation. In this cluster, at variance with what happens in more massive GCs, the second generation seems to represent at most a small minority fraction. We discuss the implications of our findings, comparing Terzan 8 with the other Sgr dSph GCs, to GCs and field stars in the Large Magellanic Cloud, Fornax, and in other dwarfs galaxies.Comment: 15 pages, 12 figures, 10 tables; accepted for publication on Astronomy and Astrophysic

Boosting Stop Searches with a 100 TeV Proton Collider

A proton-proton collider with center of mass energy around 100 TeV is the energy frontier machine that is likely to succeed the LHC. One of the primary physics goals will be the continued exploration of weak scale naturalness. Here we focus on the pair-production of stops that decay to a top and a neutralino. Most of the heavy stop parameter space results in highly boosted tops, populating kinematic regimes inaccessible at the LHC. New strategies for boosted top-tagging are needed and a simple, detector-independent tagger can be constructed by requiring a muon inside a jet. Assuming 20% systematic uncertainties, this future collider can discover (exclude) stops with masses up to 6.5 (8) TeV with 3000 fb^-1 of integrated luminosity. Studying how the exclusion limits scale with luminosity motivates going beyond this benchmark in order to saturate the discovery potential of the machine.Comment: v2: 16 pages, 17 figures, results updated using NLL+NLO cross sections, journal versio