Respostas de enzimas antioxidantes a bioativador em plântulas de milho sob estresse hídrico.

Edição Especial contendo os Anais do XVIII Congresso Brasileiro de Sementes, Florianópolis, set. 2013

Qualidade fisiológica de sementes de soja tratadas durante o armazenamento.

Edição Especial contendo os Anais do XVIII Congresso Brasileiro de Sementes, Florianópolis, set. 2013

Habitat filtering determines spatial variation of macroinvertebrate community traits in northern headwater streams

Although our knowledge of the spatial distribution of stream organisms has been increasing rapidly in the last decades, there is still little consensus about trait-based variability of macroinvertebrate communities within and between catchments in near-pristine systems. Our aim was to examine the taxonomic and trait based stability vs. variability of stream macroinvertebrates in three high-latitude catchments in Finland. The collected taxa were assigned to unique trait combinations (UTCs) using biological traits. We found that only a single or a highly limited number of taxa formed a single UTC, suggesting a low degree of redundancy. Our analyses revealed significant differences in the environmental conditions of the streams among the three catchments. Linear models, rarefaction curves and beta-diversity measures showed that the catchments differed in both alpha and beta diversity. Taxon- and trait-based multivariate analyses also indicated that the three catchments were significantly different in terms of macroinvertebrate communities. All these findings suggest that habitat filtering, i.e., environmental differences among catchments, determines the variability of macroinvertebrate communities, thereby contributing to the significant biological differences among the catchments. The main implications of our study is that the sensitivity of trait-based analyses to natural environmental variation should be carefully incorporated in the assessment of environmental degradation, and that further studies are needed for a deeper understanding of trait-based community patterns across near-pristine streams

Measurement of the CP properties of Higgs boson interactions with τ-leptons with the ATLAS detector

A study of the charge conjugation and parity (CP ) properties of the interaction between the Higgs boson and τ -leptons is presented. The study is based on a measurement of CP -sensitive angular observables defined by the visible decay products of τ -leptons produced in Higgs boson decays. The analysis uses 139 fb−1 of proton–proton collision data recorded at a centre-of-mass energy of √s=13 TeV with the ATLAS detector at the Large Hadron Collider. Contributions from CP -violating interactions between the Higgs boson and τ -leptons are described by a single mixing angle parameter ϕτ in the generalised Yukawa interaction. Without constraining the H→ττ signal strength to its expected value under the Standard Model hypothesis, the mixing angle ϕτ is measured to be 9∘±16∘ , with an expected value of 0∘±28∘ at the 68% confidence level. The pure CP -odd hypothesis is disfavoured at a level of 3.4 standard deviations. The results are compatible with the predictions for the Higgs boson in the Standard Model

Dossier: elargissement de la CEE

National audienceLes discussions au sujet de l'adhesion de l'Espagne et du Portugal a la Communaute Economique Europeenne se sont focalisees sur l'aspect europeen de l'elargissement. Mais l'agriculture mediterraneenne risque aussi beaucoup dans une telle operation. L'accentuation du clivage Europe du Nord/Sud de la mediterranee et ses consequences sur la situation alimentaire du bassin font bel et bien partie de la question de l'elargissement