Investigation of Co(OH)2 formation during cobalt electrodeposition using a chemometric procedure

AbstractThe mechanism of Co electrodeposition in sulphate solutions containing boric acid was investigated using the EQCM technique and potentiostatic measurements. The effects of solution composition, temperature and deposition potential were studied using factorial design as a chemometric procedure. The boric acid was used as a buffer to prevent pH changes due to the hydrogen evolution reaction (HER) during electrodeposition. The results showed that Co(OH)2 was formed as a parallel reaction to metallic Co formation under some experimental conditions. The analysis of the factorial design revealed that temperature and [Co2+:H3BO3] molar ratio were the critical variables that affect the mechanism of cobalt electrodeposition. At high temperatures (48°C) and using a 5:1 molar ratio of [Co2+:H3BO3], the formation of cobalt hydroxide was detected simultaneously with cobalt deposition

FGF/heparin differentially regulates Schwann cell and olfactory ensheathing cell interactions with astrocytes: a role in astrocytosis

After injury, the CNS undergoes an astrocyte stress response characterized by reactive astrocytosis/proliferation, boundary formation, and increased glial fibrillary acidic protein (GFAP) and chondroitin sulfate proteoglycan (CSPG) expression. Previously, we showed that in vitro astrocytes exhibit this stress response when in contact with Schwann cells but not olfactory ensheathing cells (OECs). In this study, we confirm this finding in vivo by demonstrating that astrocytes mingle with OECs but not Schwann cells after injection into normal spinal cord. We show that Schwann cell-conditioned media (SCM) induces proliferation in monocultures of astrocytes and increases CSPG expression in a fibroblast growth factor receptor 1 (FGFR1)-independent manner. However, SCM added to OEC/astrocyte cocultures induces reactive astrocytosis and boundary formation, which, although sensitive to FGFR1 inhibition, was not induced by FGF2 alone. Addition of heparin to OEC/astrocyte cultures induces boundary formation, whereas heparinase or chlorate treatment of Schwann cell/astrocyte cultures reduces it, suggesting that heparan sulfate proteoglycans (HSPGs) are modulating this activity. In vivo, FGF2 and FGFR1 immunoreactivity was increased over grafted OECs and Schwann cells compared with the surrounding tissue, and HSPG immunoreactivity is increased over reactive astrocytes bordering the Schwann cell graft. These data suggest that components of the astrocyte stress response, including boundary formation, astrocyte hypertrophy, and GFAP expression, are mediated by an FGF family member, whereas proliferation and CSPG expression are not. Furthermore, after cell transplantation, HSPGs may be important for mediating the stress response in astrocytes via FGF2. Identification of factors secreted by Schwann cells that induce this negative response in astrocytes would further our ability to manipulate the inhibitory environment induced after injury to promote regeneration

Non-Gaussian effects on quantum entropies

AbstractA deduction of generalized quantum entropies within the non-Gaussian frameworks, Tsallis and Kaniadakis, is derived using a generalized combinatorial method and the so-called q and κ calculus. In agreement with previous results, we also show that for the Tsallis formulation the q-quantum entropy is well-defined for values of the nonextensive parameter q lying in the interval [0,2]

A deep study of the most massive galaxy cluster at z>1.5

The X-ray satellite Chandra is the only telescope able to provide high-resolution (~1 arcsec) images in the X-ray band (0.5-10 keV). An international collaboration met in January 2014 at the Villa Il Gioiello to discuss the Chandra Large Program on the high redshift (z=1.58) galaxy cluster XDCP J0044.0-2033, constituting the deepest X-ray observation currently achieved on a massive, high redshift cluster. Thanks to this unprecedented observation, coupled to a wealth of optical and IR data, we are able to investigate the properties of the Intra Cluster Medium, star formation and nuclear activity in the cluster galaxies, and to measure the total mass of the cluster, for the first time at such a high redshift

Qubits from Number States and Bell Inequalities for Number Measurements

Bell inequalities for number measurements are derived via the observation that the bits of the number indexing a number state are proper qubits. Violations of these inequalities are obtained from the output state of the nondegenerate optical parametric amplifier.Comment: revtex4, 7 pages, v2: results identical but extended presentation, v3: published versio

A Contingent Valuation Study Of Buriti (mauritia Flexuosa L.f.) In The Main Region Of Production In Brazil: Is Environmental Conservation A Collective Responsibility?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The immature leaves of the buriti palm (Mauritia flexuosa) are widely harvested in the municipality of Barreirinhas, Maranhão, for the production of handicrafts, which are sold to locals and tourists. The increasing demand for these artisanal goods is stimulating the emergence of an informal market for immature buriti leaves, leading to an intensification of their extraction and resulting in negative effects on local buriti palm populations and the ecosystem. Thus, the objective of the present study was to assess the environmental value of the buriti palm tree based on the maximum willingness to pay (WTP) for its conservation, using the contingent valuation method. Among the respondents, 99.74% reported that the palm species should be protected and the majority of them (65.75%) agreed to pay for its conservation (annual WTP R$ 179.49 ± 222.05). Multivariate analysis revealed that the WTP was not influenced by the socio-economic profile of the respondents. The main reasons for non-WTP are related to dissatisfaction with the government and the belief that financial contributions would not solve problems of environmental damage. Overall, the evaluated population believes that environmental conservation is not an obligation of the government or that of the population, but is a collective responsibility. © 2016, Sociedade Botanica do Brasil. All rights reserved.304532539CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorMOE, Ministry of EducationCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Utilização potencial do lenho de Acacia melanoxylon a crescer em povoamentos puros ou mistos com Pinus pinaster pela indústria florestal portuguesa

A Acacia melanoxylon R. Br. (acácia-austrália ou austrália) cresce bem em Portugal, em povoamentos puros ou mistos com Pinus pinaster Aiton, ainda que apresente fortes constrangimentos ecológicos e legais. Apesar de algumas dificuldades, por exemplo na secagem, a madeira de austrália é usada em mobiliário e produtos manufacturados devido, principalmente, à sua textura e cor escura. Pode também ser usada para pasta, sendo plantada em muitos países com esse propósito juntamente com Acacia mangium e A. dealbata. O seu potencial papeleiro tem sido estudado por vários autores (CLARK et al., 1991; GUIGAN et al., 1991; FURTADO, 1994; GIL et al., 1999; PAAVILAINEN, 2000; SANTOS et al., 2002; SANTOS et al., 2006). A indústria florestal em Portugal depende fortemente do pinheiro-bravo e do eucalipto, com a consequente competição negativa, entre as várias indústrias, para a mesma matéria-prima. Em Portugal existem muitos povoamentos espontâneos com acácia, nomeadamente A. dealbata e A. melanoxylon. Enquanto a A. dealbata é considerada um problema ecológico, a A. melanoxylon não o é e está bem adaptada às condições portuguesas. Por este motivo poderá ser considerada uma espécie produtora de matéria-prima alternativa das serrações e da indústria papeleira, e poderá evitar largas áreas de monocultura e minimizar o risco de incêndio. O acréscimo anual em diâmetro da acácia (0,89 cm.ano-1) excede o do pinheiro-bravo (0,58 a 0,85 cm.ano-1) (TAVARES et al., 2004) e aproxima-se do eucalipto (0,84 a 0,96 cm.ano-1) (TOMÉ et al., 2001). As propriedades da madeira sólida de acácia (Massa volúmica média - 650 kg.m-3 ± 75, Tensão média de rotura à flexão ± sd - 146 N.mm-2 ± 24, Módulo de elasticidade médio ± sd - 14200 N.mm-2 ± 2160 e Tensão média de rotura à compressão axial ± sd - 61 N.mm-2 ± 7) permitem considerá-la uma espécie alternativa ao pinheiro-bravo (630 kg.m-3 ± 75, 130 N.mm-2 ± 33, 10500 N.mm-2 ± 3590 e 47 N.mm-2 ± 10) (MACHADO e CRUZ, 2005). As madeiras de pinheiro-bravo e de acácia podem ser, em geral, classificadas como de fraca a média densidade, de média resistência e rigidez. A qualidade do pinho é muito variável, sendo o seu potencial reconhecido a partir de dados provenientes de povoamentos de elevada qualidade (MACHADO e CRUZ, 2005). Relativamente ao potencial papeleiro, para uma dada resistência à drenagem (30 ºSR), os papeis produzidos a partir de acácia apresentam densidades aparentes mais elevadas que as de eucalipto (0,80 to 0,66 g/cm3) (SANTOS et al., 2004). Isto é devido à menor massa linear e mais elevada flexibilidade e colapsabilidade das suas fibras (SANTOS et al., 2006). Apesar do ligeiramente maior comprimento de fibra, esta produz papeis com boa relação entre a dispersão de luz e a lisura, ainda com boa resistência à tracção e a baixos níveis de consumo de energia na refinação. Este comportamento demonstra que as fibras de acácia apresentam um potencial de utilização interessante, pelo menos quando usadas juntamente com fibras de eucalipto na produção de papel para impressão e escrita. Este artigo diz respeito à análise do potencial da acácia como fonte de matéria-prima para a indústria Portuguesa (como madeira sólida e pasta e papel), reunindo informação da gestão florestal, da qualidade da madeira e da fibra. Será usado conhecimento adquirido em projectos de investigação anteriores e resultados preliminares da investigação em curso sobre A. melanoxylon proveniente de povoamento mistos (com P. pinaster) e puros, no norte de Portugal

Dark energy as a curvature of space-time induced by quantum vacuum fluctuations

It is shown that quantum vacuum fluctuations give rise to a curvature of space-time of the order appropriate to explain the observed accelerated expansion of the universe. The fact that the fluctuations produce curvature, even if the expectation of the vacuum energy vanishes, is a consequence of the non-linear character of the Einstein equation. A calculation is made, involving plausible hypotheses within quantized gravity, which establishes a relation between the two-point correlation of the vacuum fluctuations and the space-time curvature.Comment: Accepted in Astrophysics and Space Scienc

Ammonia levels on in vitro degradation of fibrous carbohydrates from buffel grass

This study was carried out to examine the degradation dynamics of neutral detergent fibre (NDF) and the profile of volatile fatty acids that originate from the fermentation of buffel grass (Cenchrus ciliaris, L.) with various levels of ammonia in the growth medium. The treatments consisted of six levels of ammonia in the growth medium (0, 5, 10, 15, 20 and 30 mg/dL), which were obtained by adding urea. These in vitro incubation times were evaluated in three replicates per time for 0, 3, 6, 9, 12, 24, 36, 48, 72 and 96 hours. Rumen concentrations of acetate and propionate responded quadratically to the ammonia levels. The treatment with 15 mg/dL of ammonia nitrogen in the rumen fluid provided mean acetate and propionate contents of 57.6 mM and 23.1 mM, respectively. Urea addition elevated the degradation rate of potentially degradable fraction of NDF (pdNDF) from 2.5% to 20.1% in comparison with the treatment without urea and to a reduction in estimated discrete lag time from 0.34 to 2.31 hours. Urea supplementation increased the specific microorganism growth rate from 2.6% to 20.1%. At the end of the incubation trial, NDF degradation showed a quadratic response, with maximum value obtained at 17.76 mg/dL of ammonia in the rumen fluid. Urea improves the degradation dynamics of NDF from deferred buffel grass and increases the concentrations of acetate and propionate.Keywords: Cenchrus ciliaris, degradation kinetics, non-protein nitrogen, ure