119 research outputs found
Purity as a witness for initial system-environment correlations in open-system dynamics
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
Thermal/electrical properties and texture of carbon black pc polymer composites near the electrical percolation threshold
Polycarbonate (PC), a thermoplastic polymer with excellent properties, is used in many advanced technological applications. When PC is blended with other polymers or additives, new properties, such as electrical properties, can be available. In this study, carbon black (CB) was melt-compounded with PC to produce polymer compounds with compositions (10–16 wt.% of CB), which are close to or above the electrical percolation threshold (13.5–14 wt.% of CB). Effects due to nanofiller dispersion/aggregation in the polymer matrix, together with phase composition, glass transition temperature, morphology and textural properties, were studied by using thermal analysis methods (thermogravimetry and differential scanning calorimetry) and scanning electron microscopy. The DC electrical properties of these materials were also investigated by means of electrical conductivity measurements and correlated with the “structure” of the CB, to better explain the behaviour of the composites close to the percolation threshold
Identifying plant species using architectural features of leaf microscopy images
This work proposes an analytical method to identify plant species based on microscopy images of the midrib cross-section of leaves. Unlike previous shape-based approaches based on the individual shape of external contours and cells, an architectural analysis is proposed, where the midrib is semi-automatically segmented and partitioned into histologically relevant structures composed of layers of cells and vascular structures. Using a sequence of morphological operations, a set of geometrical measures from the cells in each layer is extracted to produce a vector of features for species categorization. The method applied to a database containing 10 species of plants from the Brazilian flora achieved a success rate of 91.7%, outperforming other classical shape-based approaches published in the literature.Fil: Florindo, Joao Batista. Universidade de Sao Paulo; BrasilFil: Bruno, Odemir Martinez. Universidade de Sao Paulo; BrasilFil: Rossatto, Davi Rodrigo. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Kolb, Rosana Marta. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Gómez, María Cecilia. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Landini, Gabriel. University Of Birmingham; Reino Unid
Systematics of Palicoureeae (Rubiaceae): recent advances in Brazilian groups
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
Gold Coast diagnostic criteria increase sensitivity in amyotrophic lateral sclerosis
Objective: This study evaluates diagnostic accuracy of the proposed ‘Gold Coast’ (GC) diagnostic criteria for amyotrophic lateral sclerosis (ALS). Methods: Five European centres retrospectively sampled consecutive patients referred for electromyography on suspicion of ALS. Patients were classified according to the GC criteria, the revised El Escorial (rEE) criteria and the Awaji (AW) criteria without and with the ‘Possible’ category (+ Poss). Reference standard was ALS confirmed by disease progression at follow-up. Results: Of 404 eligible patients 272 were diagnosed as ALS, 94 had mimicking disorders, 35 were lost for follow-up, and three had insufficient data. Sensitivity for the GC criteria was 88.2% (95% CI: 83.8-91.8%), which was higher than for previous criteria, of which the AW + Poss criteria reached the highest sensitivity of 77.6% (95% CI: 72.2–82.4%) (p < 0.001). Specificity was high for all criteria. The increase in sensitivity for the GC criteria was mainly due to the inclusion of 28 patients with progressive muscular atrophy (PMA). Conclusions: The simpler GC criteria increase the sensitivity, primarily due to considering PMA as a form of ALS with high specificity preserved. Significance: This validation study supports that GC criteria should be used in clinical practice and may be used for inclusion in trials
Gene expression and activity of antioxidant enzymes in rice plants, cv. BRS AG, under saline stress.
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
- …