73 research outputs found

    Purity as a witness for initial system-environment correlations in open-system dynamics

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    We study the dynamics of a two-level atom interacting with a Lorentzian structured reservoir considering initial system-environment correlations. It is shown that under strong system-reservoir coupling the dynamics of purity can determine whether there are initial correlations between system and environment. Moreover, we investigate the interaction of two two-level atoms with the same reservoir. In this case, we show that besides determining if there are initial system-environment correlations, the dynamics of the purity of the atomic system allows the identification of the distinct correlated initial states. In addition, the dynamics of quantum and classical correlations is analyzed.Comment: 6 pages, 3 figure

    Systematics of Palicoureeae (Rubiaceae): recent advances in Brazilian groups

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    Palicoureeae (Rubiaceae) has its centre of diversity in the neotropics and comprises about 1500 species. Two genera with great diversity considering the Brazilian Flora are Palicourea Aubl. and Rudgea Salisb. with ca 170 and 70 species, respectively. These numbers are still underestimated, especially because several species of Psychotria L. subgenus Heteropsychotria Steyerm. need to be transferred to Palicourea, and there are several undescribed species of Rudgea. Some of our recent studies focused on resolving some taxonomic gaps and phylogenetic questions with these genera. Considering Palicourea, phylogenetic analyses are being conducted with sections Codonocalyx, Solenocalyx, and Suteria, which include 15 species of Atlantic Forest. The monophyly of sections is being tested using molecular markers. Considering Rudgea, we are investigating its diversity in the Northeast region of Brazil, trying to answer how many species occur in the region and how climatic changes may affect its distribution. Besides, the domatia of Rudgea are also being investigated, since these structures have an important taxonomic value, but its description is not very clear in the literature. These studies are being conducted with field work, especially in eastern Brazil, exsiccatae analyses, mostly from Brazilian herbaria, and from images of digital herbaria. The phylogenetic analyses used rps16, psbA-trnH, trnL-F, and ITS markers, and were conducted using maximum likelihood and Bayesian inference. Regarding the phylogenetic inference of Palicourea, the preliminary results showed that Codonocalyx, Solenocalyx, and Suteria do not have molecular support to be sustained as monophyletic taxa. Regarding the diversity of Rudgea, there are at least 22 (~31% of the total) species in Northeast Brazil, with 18 occurring in the state of Bahia. However, there are 12 uncertain taxa still being analysed. Finally, a new proposal to classify the domatia of Rudgea is being carried out, to accommodate variation and intermediate types of domatia. Acknowledgments: CAPES, FAPES, and FAPESP

    Gene expression and activity of antioxidant enzymes in rice plants, cv. BRS AG, under saline stress.

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    Made available in DSpace on 2017-11-02T09:00:26Z (GMT). No. of bitstreams: 1 ArianoArtigoenzimaspublicado.pdf: 618231 bytes, checksum: e491e5e834a33c8646332de8188f1b17 (MD5) Previous issue date: 2017-10-31bitstream/item/165861/1/Ariano-Artigo-enzimas-publicado.pd

    Selection of Reference Genes for RT-qPCR Studies in Different Organs of Rice Cultivar BRS AG Submitted to Recurrent Saline Stress.

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    Quantitative real-time polymerase chain reactions (RT-qPCR) have become one of the most widely used methods for analyzing gene expression, provided suitable reference genes are available to normalize the data. RNA was isolated from leaves, grain, rachises and sheaths of rice (Oryza sativa L. cv. BRS AG) submitted to different saline stress events for seven days, and expression analysis was carried out by RT-qPCR. Expression levels of ten candidate reference genes were assessed, actin11 (ACT11), ubiquitin conjugating enzyme E2 (UBC-E2), eukaryotic elongation factor1-a (Eef-1a), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), B-tubulin (B-Tub), eukaryotic initiation factor 4a (Eif-4-a), ubiquitin10 (UBQ10), ubiquitin5 (UBQ5), aquaporin TIP41 (TIP41-like). Gene expression stability was calculated using the common statistical algorithms geNorm, BestKeeper and ?Ct method, NormFinder and RefFinder. The most stably expressed genes were UBC2E and GAPDH for leaves, UBQ5 and UBQ10 for sheaths, TIP41 and UBQ10 for rachises, and TIP41 and cyclophilin for grain. Gene expression of triose phosphate translocator (TPT1), ADP-glucose transporter (BT1-1), choline monooxygenase (CMO) was used to validate the selected reference genes. The results highlighted the importance of using suitable reference gene to normalize gene expression data in rice plants

    Evaluation of the genotoxic and antigenotoxic potential of Melissa officinalis in mice

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    Melissa officinalis (L.) (Lamiaceae), a plant known as the lemon balm, is native to the east Mediterranean region and west Asia. Also found in tropical countries, such as Brazil, where it is popularly known as “erva-cidreira” or “melissa”, it is widely used in aqueous- or alcoholic-extract form in the treatment of various disorders. The aim was to investigate in vivo its antigenotoxicity and antimutagenicity, as well as its genotoxic/mutagenic potential through comet and micronucleus assaying. CF-1 male mice were treated with ethanolic (Mo-EE) (250 or 500 mg/kg) or aqueous (Mo-AE) (100 mg/kg) solutions of an M. officinalis extract for 2 weeks, prior to treatment with saline or Methyl methanesulfonate (MMS) doses by intraperitoneal injection. Irrespective of the doses, no genotoxic or mutagenic effects were observed in blood and bone-marrow samples. Although Mo-EE exerted an antigenotoxic effect on the blood cells of mice treated with the alkylating agent (MMS) in all the doses, this was not so with Mo-AE. Micronucleus testing revealed the protector effect of Mo-EE, but only when administered at the highest dose. The implication that an ethanolic extract of M. officinalis has antigenotoxic/antimutagenic properties is an indication of its medicinal relevance
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