Physical processes leading to surface inhomogeneities: the case of rotation

In this lecture I discuss the bulk surface heterogeneity of rotating stars, namely gravity darkening. I especially detail the derivation of the omega-model of Espinosa Lara & Rieutord (2011), which gives the gravity darkening in early-type stars. I also discuss the problem of deriving gravity darkening in stars owning a convective envelope and in those that are members of a binary system.Comment: 23 pages, 11 figure, Lecture given to the school on the cartography of the Sun and the stars (May 2014 in Besan\c{c}on), to appear in LNP, Neiner and Rozelot edts V2: typos correcte

Efeito de genótipos de sorgo sobre o predador Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) alimentado com Schizaphis graminum (Rondani) (Hemiptera: Aphididae).

O trabalho objetivou avaliar o efeito indireto da resistência de genótipos de soro sobre o predador Chrysoperla externa (Hagen) usando o pulgão Schizaphis graminum (Rondani) como presa. Os genótipos usados no estudo foram: GR 11111 e TX 430 x GR 111 (resistentes), GB 3B (moderadamente resistente) e BR 007B (suscetível). Larvas recém-eclodidas foram confinadas individualmente em recipientes de vidro e alimentadas com S. graminum, criados separadamente em cada um dos quatro genótipos. após a emergência, os adultos obtidos de cada tratamento foram sexados e agrupados aos casais, colocados em gaiolas contendo dieta à base de levedo de cerveja e mel. Os insetos foram observados diariamente da fase jovem até o período de 60 dias após a emergência do adulto. Genótipos com maior grau de resistência proporcionaram maior consumo de pulgões pelo predador, porém menor peso a este. Quando os pulgões foram criados no genótipo resistente GR 11111, o peso das larvas, sobrevivência da pré-pupa e longevidade da fêmea do predador foram inferiores. As associações positivas observadas entre o predador, C. externa, e o genótipo resistente, TX 430 x GR 111, e entre o predador e o genótipo moderadamente resistente GB 3B, evidenciaram a possibilidade de integração entre os dois métodos de controle: resistência de plantas e controle biológico

Flipping the Tortilla: Social-ecological innovations and traditional ecological knowledge for more sustainable agri-food systems in Spain

The conventional dominant global agri-food system is a main driver in the Anthropocene: food production entails profound global environmental changes from greenhouse gas emissions to biodiversity loss, and shifting diets further impact planetary and human health. Innovative approaches are needed to shift towards more sustainable, equitable and healthy agri-food systems. Building on the increasing recognition of the relevance of traditional agroecological knowledge (TAeK) in sustainable food systems, this paper aims to describe innovative agri-food initiatives and explore how the use and valorization of TAeK may transform conventional agri-food systems. It employs a case-study approach in Spain, where we conducted semi-structured interviews with 12 representatives of alternative agri-food initiatives. We found that, to promote sustainable agri-food systems, TAeK has to span from farm-to-fork. Innovative agroecological practices and knowledge help to safeguard biocultural diversity, while gastronomic knowledge among consumers on how to process and prepare local varieties and species is crucial for the implementation of shorter value chains. We discuss how TAeK enhances the success of conventional systems of innovation, challenging dominant epistemological frameworks. By scaling deep (changing values), scaling out (dissemination, reproduction) and scaling up (changing institutions), the agri-food initiatives may act on leverage points to enable broader transformation of the Spanish agri-food system

Evidence of ongoing radial migration in NGC 6754: Azimuthal variations of the gas properties

Understanding the nature of spiral structure in disk galaxies is one of the main, and still unsolved questions in galactic astronomy. However, theoretical works are proposing new testable predictions whose detection is becoming feasible with recent development in instrumentation. In particular, streaming motions along spiral arms are expected to induce azimuthal variations in the chemical composition of a galaxy at a given galactic radius. In this letter we analyse the gas content in NGC 6754 with VLT/MUSE data to characterise its 2D chemical composition and H$\alpha$ line-of-sight velocity distribution. We find that the trailing (leading) edge of the NGC 6754 spiral arms show signatures of tangentially-slower, radially-outward (tangentially-faster, radially-inward) streaming motions of metal-rich (poor) gas over a large range of radii. These results show direct evidence of gas radial migration for the first time. We compare our results with the gas behaviour in a $N$-body disk simulation showing spiral morphological features rotating with a similar speed as the gas at every radius, in good agreement with the observed trend. This indicates that the spiral arm features in NGC 6754 may be transient and rotate similarly as the gas does at a large range of radii.Comment: 8 pages, 4 figures, accepted for publication in ApJL 2016 September 2

Modeling the variance-covariance matrix of genetic and residual effects in a Panicum maximum genome wide selection experiment.

Panicum maximum stands out among the tropical forage species due to its high biomass yield and excellent nutritional quality, providing high animal performance. The improvement of sexual plant population of P. maximum by recurrent selection increases the probability of releasing superior cultivars. In this work, we aimed to model variance-covariance matrices for genetic (G) and residual (R) effects in a spaced plant experiment to obtain adjusted means that will be used in a recurrent genomic selection program