Search for Associations Containing Young stars (SACY): Chemical tagging IC 2391 & the Argus association

We explore the possible connection between the open cluster IC 2391 and the unbound Argus association identified by the SACY survey. In addition to common kinematics and ages between these two systems, here we explore their chemical abundance patterns to confirm if the two substructures shared a common origin. We carry out a homogenous high-resolution elemental abundance study of eight confirmed members of IC 2391 as well as six members of the Argus association using UVES spectra. We derive spectroscopic stellar parameters and abundances for Fe, Na, Mg, Al, Si, Ca, Ti, Cr, Ni and Ba. All stars in the open cluster and Argus association were found to share similar abundances with the scatter well within the uncertainties, where [Fe/H] = -0.04 +/-0.03 for cluster stars and [Fe/H] = -0.06 +/-0.05 for Argus stars. Effects of over-ionisation/excitation were seen for stars cooler than roughly 5200K as previously noted in the literature. Also, enhanced Ba abundances of around 0.6 dex were observed in both systems. The common ages, kinematics and chemical abundances strongly support that the Argus association stars originated from the open cluster IC 2391. Simple modeling of this system find this dissolution to be consistent with two-body interactions.Comment: 17 pages, 7 figs, accepted for publication in MNRA

Polpas branqueadas de misturas de madeiras da Amazônia.

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Characterization of the regulatory region of bovine mucin 2 (MUC2) gene.

Na publicação: E. O. Melo

Effect of arbuscular mycorrhizal fungi on the acclimatization of micropropagated banana plantlets.

The effect of arbuscular mycorrhizal fungi (AMF) on micropropagated banana plantlets was evaluated during the acclimatization period. Plants were inoculated with Acaulospora scrobiculata, Glomus clarum or Glomus etunicatum. After cultivation in a greenhouse for 3 months, height, leaf area, fresh weight and dry matter of root and shoots, level of AMF colonization, nutrient level, photosynthesis and transpiration rate, water potential and stomatal conductance were measured. The number of AMF spores produceded in each treatment was also determined. Plantlets inoculated with Amf had greater height, leaf area and fresh weight of shoots and roots, as well as higher rates of photosynthesis and transpiration than controls. Plants inoculated with Glomus were superior in most of the evaluated parameters

Why pair production cures covariance in the light-front?

We show that the light-front vaccum is not trivial, and the Fock space for positive energy quanta solutions is not complete. As an example of this non triviality we have calculated the electromagnetic current for scalar bosons in the background field method were the covariance is restored through considering the complete Fock space of solutions. We also show thus that the method of "dislocating the integration pole" is nothing more than a particular case of this, so that such an "ad hoc" prescription can be dispensed altogether if we deal with the whole Fock space. In this work we construct the electromagnetic current operator for a system composed of two free bosons. The technique employed to deduce these operators is through the definition of global propagators in the light front when a background electromagnetic field acts on one of the particles.Comment: 11 pages, 2 figure

Karyotype, C-and fluorescence banding patterns, NOR location and FISH in the grasshopper Xestotrachelus robustus (Romaleidae).

Different techniques involving fluorochrome staining, C-banding, NOR location and FISH were used in order to characterize the karyotype and to determine the characteristics of the constitutive heterochromatin in the genome of grasshopper Xestotrachelus robustus. This species presents uniform karyotype in terms of chromosome number (2n=23, XO in males) but deffered in the morphology of some chromosomes of the complement. Fluorescence in situ hybridization (FISH) was applied to the location of 45S genes. The results of FISH are compared with those coming from classical cytogenetics (C, AgNO3 and CMA3) banding procedures

Cálculo de graus-dia acumulados para subsidiar ações de gerenciamento de risco de pragas.

O presente trabalho teve por objetivo apresentar as operações de um dos métodos de cálculo de graus-dia acumulados (vulgarmente conhecido como ?método do retângulo?), através de dois exemplos, um para um inseto e o outro para um nematóide, em localidade com disponibilidade de dados necessários ao cálculo de graus-dia.2. APLICAÇÃO DO USO DE GRAUS-DIA PARA PRAGAS PRESENTES EM ÁREAS DE PRODUÇÃO AGRÍCOLA NO BRASILbitstream/CENARGEN/27920/1/cot145.pd