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International audience; In this paper we introduce a definition of approximate Pareto efficient solution as well as a necessary condition for such solutions in the multiobjective setting on Riemannian manifolds. We also propose an inexact proximal point method for nonsmooth multiobjective optimization in the Riemannian context by using the notion of approximate solution. The main convergence result ensures that each cluster point (if any) of any sequence generated by the method is a Pareto critical point. Furthermore, when the problem is convex on a Hadamard manifold, full convergence of the method for a weak Pareto efficient solution is obtained. As an application, we show how a Pareto critical point can be reached as a limit of traps in the context of the variational rationality approach of stay and change human dynamics.

Parasitoids of three mealybug pests (Hemiptera: Pseudococcidae), Planococcus ficus (Signoret), Pseudococcus sociabilis Hambleton, and Pseudococcus viburni (Signoret) have been identified for the first time in Brazil. Mealybugs were collected in fruit-growing areas along southern Brazil during 2013-2016. An integrative approach, combining morphological and molecular methods, was used to identify the Brazilian parasitoids to the species level. Fifteen species were recorded, including 14 primary parasitoids belonging to Encyrtidae and Platygastridae and a single secondary parasitoid species belonging to Signiphoridae. The encyrtid parasitoids Acerophagus flavidulus (Brethes), Anagyrus calyxtoi Noyes and Zaplatycerus sp., and the signiphorid secondary parasitoid Chartocerus axillaris De Santis are reported for the first time in Brazil., Centro de Estudios Parasitológicos y de Vectores, Centro de Investigación en Sanidad Vegetal

International audience; A root-knot nematode (RKN) parasitizing rice (Oryza sativaL.) and causing damage in Santa Catarina (SC), Rio Grande do Sul (RS) and Parana (PR) states (Brazil) was identified asMeloidogyne ottersoni(Thorne1969) Franklin1971. The species is redescribed from the Brazilian population from Meleiro (SC) and compared with the description ofM. ottersonifrom Wind Lake (Wisconsin, USA) with additional morphological, biochemical and molecular characterization. The female and male bear smaller stylets: 10-12 mu m, 14-16 mu m, respectively, when compared withM. graminicola: 12-14 mu m, 16-18 mu m, andM. oryzae: 14-16 mu m, 18-20 mu m.Meloidogyne ottersonipresents perineal patterns located on the contour of a slight protuberance. Striae are mostly continuous, never raised by transverse irregular striae, as frequently observed inM. graminicolaandM. oryzae.Meloidogyne ottersonibelongs to the RKN group 11 described by Jepson (1987); the reproduction is by meiotic parthenogenesis and the somatic chromosome number is 18. The tail of second-stage juveniles is very long and thin, and tapers to a long, narrow, irregular hyaline terminus (M. ottersoni, 20.5 mu mvs M. graminicola,17.9 mu m andM. oryzae, 22.0 mu m, respectively). The ability of the BrazilianM. ottersonipopulation to parasitize canary grass,Phalaris arundinaceaL. (type host), and barnyard grass,Echinocloa crus-galli,was confirmed. Biochemically, the esterase profile ofM. ottersonilacks any band (Est Ot0, Rm=0), which differentiates it fromM. graminicolaandM. oryzae(Est VS1, Rm=0.70 and Est O1,Rm=1.02, respectively). In Maximum Likelihood analysis of ITS, D2D3 and COXII-16S rRNA sequences, populations ofM. ottersonifrom different states of Brazil clustered together and were separated from otherMeloidogynespp., thus confirming that all four populations are very similar and conspecific.

Nematodes and drought are major constraints in tropical agriculture and often occur simultaneously. Plant responses to these stresses are complex and require crosstalk between biotic and abiotic signaling pathways. In this study, we explored the transcriptome data of wild Arachis species subjected to drought (A-metaDEG) and the root-knot nematode Meloidogyne arenaria (B-metaDEG) via meta-analysis, to identify core-stress responsive genes to each individual and concurrent stresses in these species. Transcriptome analysis of a nematode/drought bioassay (cross-stress) showed that the set of stress responsive DEGs to concurrent stress is distinct from those resulting from overlapping A- and B-metaDEGs, indicating a specialized and unique response to combined stresses in wild Arachis. Whilst individual biotic and abiotic stresses elicit hormone-responsive genes, most notably in the jasmonic and abscisic acid pathways, combined stresses seem to trigger mainly the ethylene hormone pathway. The overexpression of a cross-stress tolerance candidate gene identified here, an endochitinase-encoding gene (AsECHI) from Arachis stenosperma, reduced up to 30% of M. incognita infection and increased post-drought recovery in Arabidopsis plants submitted to both stresses. The elucidation of the network of cross-stress responsive genes in Arachis contributes to better understanding the complex regulation of biotic and abiotic responses in plants facilitating more adequate crop breeding for combined stress tolerance.

Since the discovery of graphene oxide (GO), the most accessible of the precursors of graphene, this material has been widely studied for applications in science and technology. In this work, we describe a procedure to obtain GO dispersions in water at high concentrations, these highly dehydrated dispersions being in addition fully redispersible by dilution. With the availability of such concentrated samples, it was possible to investigate the structure of hydrated GO sheets in a previously unexplored range of concentrations, and to evidence a structural phase transition. Tentatively applying models designed for describing the small-angle scattering curve in the Smectic A (or L$_{\alpha}$) phase of lyotropic systems, it was possible to extract elastic parameters characterising the system on the dilute side of the transition, thereby evidencing the relevance of both electrostatic and steric (Helfrich) interactions in stabilising aqueous lamellar stacks of GO sheets, Comment: 11 pages, 10 figures