Characterization and quantification of symmetric Gaussian state entanglement through a local classicality criterion

A necessary and sufficient condition for characterization and quantification of entanglement of any bipartite Gaussian state belonging to a special symmetry class is given in terms of classicality measures of one-party states. For Gaussian states whose local covariance matrices have equal determinants it is shown that separability of a two-party state and classicality of one party state are completely equivalent to each other under a nonlocal operation, allowing entanglement features to be understood in terms of any available classicality measure.Comment: 5 pages, 1 figure. Replaced with final published versio

Operational Classification and Quantification of Multipartite Entangled States

We formalize and extend an operational multipartite entanglement measure introduced by T. R. Oliveira, G. Rigolin, and M. C. de Oliveira, Phys. Rev. A 73, 010305(R) (2006), through the generalization of global entanglement (GE) [D. A. Meyer and N. R. Wallach, J. Math. Phys. 43, 4273 (2002)]. Contrarily to GE the main feature of this measure lies in the fact that we study the mean linear entropy of all possible partitions of a multipartite system. This allows the construction of an operational multipartite entanglement measure which is able to distinguish among different multipartite entangled states that GE failed to discriminate. Furthermore, it is also maximum at the critical point of the Ising chain in a transverse magnetic field, being thus able to detect a quantum phase transition.Comment: 14 pages, RevTex4, published versio

Symmetry breaking effects upon bipartite and multipartite entanglement in the XY model

We analyze the bipartite and multipartite entanglement for the ground state of the one-dimensional XY model in a transverse magnetic field in the thermodynamical limit. We explicitly take into account the spontaneous symmetry breaking in order to explore the relation between entanglement and quantum phase transitions. As a result we show that while both bipartite and multipartite entanglement can be enhanced by spontaneous symmetry breaking deep into the ferromagnetic phase, only the latter is affected by it in the vicinity of the critical point. This result adds to the evidence that multipartite, and not bipartite, entanglement is the fundamental indicator of long range correlations in quantum phase transitions.Comment: 13 pages, 19 figures, comments welcome. V2: small changes, published versio

Content validation and inter-rater reliability of a protocol for the precision assessment of boccia players

Purpose: To verify a protocol's content validation and reliability for assessing the precision in the throw of Paralympic boccia in two different steps. Methods: The study was divided into two steps: In step 1, the perception of 15 boccia coaches was evaluated using a questionnaire containing 6 questions about the pertinence of the protocol on a Likert scale (1 to 5). In step 2, reliability was evaluated by two researchers, applying the protocol with two targets (0.5 and 1.0, targets) to verify the short precision (SP), average precision (AP), long precision (LP), and total precision (TP) of 23 boccia athletes (BC1 = 5; BC2 = 7; BC3 = 1; BC4 = 10) in tournaments of the modality. The Content Validity Index (CVI) calculation was applied for the electronic questionnaire, the Intraclass Correlation Coefficient (ICC) for the agreement between evaluators, and the T-Test for the difference between means. p < .05 was adopted. Results: In the result of the CVI, reliability was noticed through the experts' evaluation (Question1 = 1.0; Q2 = 0.93; Q3 = 0.80; Q4 = 0.80; Q5 = 0.93; Q6 = 0.93). There was an agreement between the evaluators by the ICC in the 0.5 targets for SP (p < .01), AP (p < .01), LP (p < .01), and TP (p < .01), and in the 1.0 target for SP (p < .01), AP (p < .01), LP (p < .01), and TP (p < .01). No differences were found between the means in the t-test. Conclusion: It was demonstrated that the protocol meets the established reliability and content validity criteria, allowing its practical use to evaluate the precision in the boccia

Electrochemical generation of hydroxyl radicals for protein oxidation studies

In the last decades, different studies shown that the increase in oxidative stress is associated with the risk factors implicated in the pathophysiology of many chronic diseases. Therefore it is important to evaluate the role that hydroxyl radicals-mediated damage may play in major human disorders. Proteins are important targets as they compose ca. 70% of cells. To understand the impact of specific modifications on protein function, stability and toxicity resulting of the damage caused by the attacked of these radicals it is important to characterize the proteins oxidation products obtained from assays where hydroxyl radicals are generated by clean processes [1]. In spite of radiolysis and photolysis are adequate for this purpose they are not accessible for most laboratories. On the other hand, Fenton-like reactions are quite accessible but have many drawbacks associated to the use of chemical precursors that can bias results [2]. In this context the electrochemical generation of hydroxyl radical can provide an alternative method that is both clean and accessible, were these radicals are formed as intermediate in the oxidation of water to produce oxygen. This reaction can be accomplished in different electrode materials such as of boron doped diamond electrodes (BDD) and platinum (Pt), among others [3]. In this work we present a study were the oxidation of BSA is conducted in different experimental conditions, including the anode material (BDD and Pt), current density and electrolytes. The extension of BSA oxidation was monitored by the quantification of carbonyl groups formed during the protein oxidation and the cleavage extension, evaluated by gel electrophoresis method (SDS-PAGE).Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/64189/2009

Dissolving star cluster candidates

We present a list of 34 neglected entries from star cluster catalogues located at relatively high galactic latitudes ($|b| >$ 15$^{\circ}$) which appear to be candidate late stages of star cluster dynamical evolution. Although underpopulated with respect to usual open clusters, they still present a high number density contrast as compared to the galactic field. This was verified by means of (i) predicted model counts from different galactic subsystems in the same direction, and (ii) Guide Star Catalog equal solid angle counts for the object and surrounding fields. This suggests that the objects are physical systems, possibly star clusters in the process of disruption or their fossil remains. The sample will be useful for followup studies in view of verifying their physi cal nature.Comment: manuscript in LATEX with 7 pages, 7 figures .ps Accepted for Astronomy and Astrophysics main journa

Infecção pelo Sugarcane yellow leaf virus causa alterações na eficiência fotossintética e acúmulo de carboidratos nas folhas de cana-de-açúcar

Infection by Sugarcane yellow leaf virus (ScYLV) causes severe leaf symptoms in sugarcane (Saccharum spp.) hybrids, which indicate alterations in its photosynthetic apparatus. To gain an overview of the physiological status of infected plants, we evaluated chlorophyll a fluorescence and gas exchange assays, correlating the results with leaf metabolic surveys, i.e., photosynthetic pigments and carbohydrate contents. When compared to healthy plants, infected plants showed a reduction in potential quantum efficiency for photochemistry of photosystem (PSII) and alterations in the filling up of the plastoquinone (PQ) pool. They also showed reduction in the CO2 net exchange rates, probably as a consequence of impaired quantum yield. In addition, reductions were found in the contents of photosynthetic leaf pigments and in the ratio chlorophyll a/chlorophyll b (chla/chlb). Carbohydrate content in the leaves was increased as a secondary effect of the ScYLV infection. This article discusses the relation of virus replication and host defense responses with general alterations in the photosynthetic apparatus and in the metabolism of infected plants.O vírus do amarelecimento foliar da cana-de-açúcar (Sugarcane yellow leaf virus, ScYLV) causa sintomas foliares severos e típicos de infecção por luteovirus, em cana-de-açúcar (Saccharum spp.). Uma vez que alterações no sistema fotossintético da planta seriam esperadas, avaliaram-se a análise da emissão da fluorescência da clorofila a e as trocas gasosas durante a fotossíntese, relacionando esses dados com análises metabólicas, ou seja, conteúdos de pigmentos fotossintéticos e carboidratos presentes nas folhas. As plantas infetadas apresentaram redução na eficiência quântica fotoquímica potencial do fotossistema II (PSII) e alterações no preenchimento do pool de plastoquinona (PQ). Essas plantas apresentaram, também, redução nas taxas de troca líquida de CO2, provavelmente em conseqüência da redução na eficiência quântica. Paralelamente, reduções nos conteúdos de pigmentos fotossintéticos foliares e na razão clorofila a/clorofila b (chla/chlb) foram verificadas. Adicionalmente, o conteúdo de açúcares nas folhas foi aumentado, provavelmente como um efeito secundário da infecção viral. A relação entre a replicação viral e as respostas de defesa da hospedeira com as alterações encontradas no aparelho fotossintético e no metabolismo das plantas infetadas é discutida.101

Hepatocellular Neoplasm in a Wild-Caught Sheepshead Minnow (Cyprinodon variegatus) from the Northern Gulf of Mexico

The sheepshead minnow, Cyprinodon variegatus, is a widely distributed small fish species that inhabits estuaries and inshore waters from New England to northern South America. This species has been used extensively in aquatic environmental toxicity and carcinogenicity tests (Couch et al., 1981; Courtney and Couch, 1984). Hepatic neoplasms have been induced in the sheepshead minnow by exposure to several known chemical carcinogens including diethylnitrosamine (Couch and Courtney, 1987), methylazoxymethanolacetate (Hawkins etal., 1985), and dimethylbenz(a)anthracene (Hawkins et al., 1991). Because of its widespread distribution, limited home range, and proven sensitivity tocarcinogens, the sheepshead minnow appears to be a good candidate to serve as an in situ monitor of environmental carcinogens and other toxicants in coastal waters, especially those of the Gulf of Mexico and Caribbean Sea. To establish background information on the histopathological lesions in sheepshead minnows taken from the wild, we collected and examined specimens from an offshore site presumed to be free of chemical contamination. The present report concerns a hepatic neoplastic lesion, diagnosed as a hepatocellular adenoma, found in a wild sheepshead minnow. Neoplasms from wild sheepshead minnows or spontaneous neoplasms from laboratory specimens previously have not been reported

Chemical composition and minerals in pyrite ash of an abandoned sulphuric acid production plant

The extraction of sulphur produces a hematite-rich waste, known as roasted pyrite ash, which contains significant amounts of environmentally sensitive elements in variable concentrations and modes of occurrence. Whilst the mineralogy of roasted pyrite ash associated with iron or copper mining has been studied, as this is the main source of sulphur worldwide, the mineralogy, and more importantly, the characterization of submicron, ultrafine and nanoparticles, in coal-derived roasted pyrite ash remain to be resolved. In this work we provide essential data on the chemical composition and nanomineralogical assemblage of roasted pyrite ash. XRD, HR-TEM and FE-SEM were used to identify a large variety of minerals of anthropogenic origin. These phases result from highly complex chemical reactions occurring during the processing of coal pyrite of southern Brazil for sulphur extraction and further manufacture of sulphuric acid. Iron-rich submicron, ultrafine and nanoparticles within the ash may contain high proportions of toxic elements such as As, Se, U, among others. A number of elements, such as As, Cr, Cu, Co, La, Mn, Ni, Pb, Sb, Se, Sr, Ti, Zn, and Zr, were found to be present in individual nanoparticles and submicron, ultrafine and nanominerals (e.g. oxides, sulphates, clays) in concentrations of up to 5%. The study of nanominerals in roasted pyrite ash from coal rejects is important to develop an understanding on the nature of this by-product, and to assess the interaction between emitted nanominerals, ultra-fine particles, and atmospheric gases, rain or body fluids, and thus to evaluate the environmental and health impacts of pyrite ash materials