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Now showing items 1 - 16 of 493382

  • Development of the First Brazilian Project on Superconducting Power Cable

    Neves, M. A.   da Silva, E. P.   Rosario, M. A. P.   Lopes, A. J. S.   Branco, L. M. C.   Matias, F.   Brito, A. S.   Maia, F. C. O.   Queiroz, A. R.   Antunes, J. C.   Torres, A. M.   Costa, L.   Moldenhauer, V.   Reis, T.   Berredo, A. C. S.   Nascimento, C. A. F.   Junior, E. L. C.   Mendonca, G.   Barony, M. A. P.   Pereira, M. T. R. F.   Guimaraes, M. F.   Teixeira, P.   Hojo, T.   Alves, W. M.   Nascimento, C. A. M.  

    The SUPERCABO Project is in development in Brazil, and its primary objective is to achieve knowledge on designing, construction, tests, and economic feasibility of high-temperature superconducting power cable (HTS cable) technology for Brazil. Such knowledge is shared with four major Brazilian power utilities and with Brazil's National Electric Energy Agency. The method employed was to exchange knowledge and information with those power utilities to guide the project in giving results that allow for actual use of HTS cable technology in Brazil. The procedures were to evaluate the best geometry of HTS cable according to the operating voltage level, to search for an auxiliary solution for fault current protection, and to improve the terminations of the cable. The main outcomes and results presented here are the complete design of the first Brazilian HTS cable, the proposed termination for use in an HTS cable, and computational models for the superconducting core. As a conclusion, the SUPERCABO Project is in development, with results to improve the feasibility of HTS cable technology in Brazil, using cryocooled aluminum power cables to fault current protection and a proposal of inductive linking for power flow in terminations. Some details are not shown because they are patent pending.
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  • A relaxed projection method for solving multiobjective optimization problems

    Brito, A. S.   Cruz Neto, J. X.   Santos, P. S. M.   Souza, S. S.  

    In this paper, we propose an algorithm for solving multiobjective minimization problems on nonempty closed convex subsets of the Euclidean space. The proposed method combines a reflection technique for obtaining a feasible point with a projected subgradient method. Under suitable assumptions, we show that the sequence generated using this method converges to a Pareto optimal point of the problem. We also present some numerical results. (C) 2016 Elsevier B.V. All rights reserved.
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  • Components of the water balance in soil with sugarcane crops

    Ghiberto, P. J.   Libardi, P. L.   Brito, A. S.   Trivelin, P. C. O.  

    The objective of this study was to analyze the components of the water balance in an Ultisol, located in the municipality of Jaboticabal, SP, Brazil (21 degrees 20'20 '' S, 48 degrees 18'35 '' W), that was cultivated with sugarcane. The monitoring was performed during the agricultural cycle of the first ratoon between 11/16/2006 and 7/9/2007. Three treatments were established in four blocks with doses of ammonium sulfate, as follows: Treatment 1 (T-1), without fertilizer; Treatment 2 (T-2), 100 kg ha(-1) of nitrogen (N) and 114 kg ha(-1) of sulfur (S); and Treatment 3 (T-3), 150 kg ha(-1) of N and 172 kg ha(-1) of S. Rainy precipitation (P) in the area was measured with a rain gauge. The soil water storage (H) and the soil water storage variations (Delta H) were determined by the gravimetric method, and the internal drainage (D)/capillary rise (CR) at a depth of 0.9 m was quantified by the water flux density using the Darcy-Buckingham equation. The actual evapotranspiration (ETa) was calculated as follows: ETa =3D P - D + CR +/- Delta H. During the study period, the amount of rainfall was 1406 mm, 121 mm greater than the historic average for the region (1285 mm), with a notable peak in the month of January of 40211111 (historic average: 251 mm). The internal drainage was 300 mm under T-1, 352 mm under T-2, and 199 mm under T-3, and this was relevant during times with elevated P, when the actual H was greater than the field capacity H. The actual evapotranspiration (T-1 : -897.7 mm, T-2: -847.5 mm, and T-3: -970.8 mm) and the water use efficiency (T-1: -131.3 kg mm(-1), T-2: -146.6 kg mm(-1), and T-3: -127.5 kg mm(-1)) did not differ among the treatments. The dispersion of D was greater than the other components of the water balance, especially during the period of elevated P, with the errors of this process propagated in the estimation of ETa. Despite of this propagated standard deviation of ETa, it accounted less than 15% of the total ETa, showing that the method may be conveniently used in field studies with sugarcane crops. (C) 2011 Elsevier B.V. All rights reserved.
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  • A heparin mimetic isolated from a marine shrimp suppresses neovascularization

    Dreyfuss, J. L.   Regatieri, C. V.   Lima, M. A.   Paredes-Gamero, E. J.   Brito, A. S.   Chavante, S. F.   Belfort, R., Jr.   Farah, M. E.   Nader, H. B.  

    Background: Choroidal neovascularization (CNV) is the main cause of severe visual loss in age-related macular degeneration (AMD). Heparin/heparan sulfate are known to play important roles in neovascularization due to their abilities to bind and modulate angiogenic growth factors and cytokines. Previously, we have isolated from marine shrimp a heparin-like compound with striking anti-inflammatory action and negligible anticoagulant and hemorrhagic activities. Objectives: To investigate the role of this novel heparin-like compound in angiogenic processes. Methods and Results: The anti-angiogenic effect of this heparinoid in laser-induced CNV and in vitro models is reported. The compound binds to growth factors (FGF-2, EGF and VEGF), blocks endothelial cell proliferation and shows no cytotoxic effect. The decrease in proliferation is not related to cell death either by apoptosis or secondary necrosis. The results also showed that the heparinoid modified the 2-D network organization in capillary-like structures of endothelial cells in Matrigel and reduced the CNV area. The effect on CNV area correlates with decreases in the levels of VEGF and TGF-beta 1 in the choroidal tissue. The low content of 2-O-sulfate groups in this heparinoid may explain its potent anti-angiogenic effect. Conclusions: The properties of the shrimp heparinoid, such as potent anti-angiogenic and anti-inflammatory activities but insignificant anticoagulant or hemorrhagic actions, point to this compound as a compelling drug candidate for treating neovascular AMD and other angioproliferative diseases. A mechanism for the anti-angiogenic effect of the heparinoid is proposed.
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  • Leaching of nutrients from a sugarcane crop growing on an Ultisol in Brazil

    Libardi, P. L.   Brito, A. S.   Trivelin, P. C. O.  

    Leaching is disadvantageous, both for economical and environmental reasons since it may decrease the ecosystem productivity and may also contribute to the contamination of surface and ground water. The objective of this paper was to quantify the loss of nitrogen and sulfur by leaching, at the depth of 0.9 m, in an Ultisol in Sao Paulo State (Brazil) with high permeability, Cultivated with sugarcane during the agricultural cycle of crop plant. The following ions were evaluated: nitrite, nitrate, ammonium, and sulfate. Calcium, magnesium, potassium, and phosphate were also evaluated at the same depth. The sugarcane was planted and fertilized in the furrows with 120 log ha(-1) of N-urea. In order to find out the fate of N-fertilizer, four microplots with N-15-enriched fertilizer were installed. Input and output of the considered ions at the depth of 0.9 m were quantified from the flux density of water and the concentration of the elements in the soil solution at this soil depth: tensiometers, soil water retention curve and soil solution extractors were used for this quantification. The internal drainage was 205 mm of water, with a total loss of 18 kg ha(-1) of N and 10 kg ha(-1) of S. The percentage of N in the soil solution derived from the fertilizer (%NSSDF) was 1.34, resulting in only 25 g ha(-1) of N fertilizer loss by leaching during all agricultural cycle. Under the experimental conditions of this crop plant, that is, high demand of nutrients and high incorporation of crop residues, the leached N represented 15% of applied N and S leaching were not considerable; the higher amount of leached N was native nitrogen and a minor quantity from N fertilizer; and the leached amount of Ca, Mg, K and P did not exceed the applications performed in the crop by lime and fertilization. (C) 2009 Elsevier B.V. All rights reserved.
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  • Orientation control of KNbO3 film grown on glass substrates by Ca2Nb3O10- nanosheets seed layer

    Baudouin, F.   Demange, V.   Ollivier, S.   Rault, L.   Brito, A. S.   Maia, A. S.   Gouttefangeas, F.   Bouquet, V.   Deputier, S.   Berini, B.   Fouchet, A.   Guilloux-Viry, M.  

    KNbO3 films have been deposited by pulsed laser deposition on glass substrates covered by Ca2Nb3O10- nanosheets used as seed layer, for the purpose of promoting (001) preferential orientation. Nanosheets have been prepared by the exfoliation process of HCa2Nb3O10 phase that is obtained by cation exchange of the Dion-Jacobson KCa2Nb3O10 phase in an acidic solution. Electron diffraction in transmission electron microscopy performed on KCa2Nb3O10 and HCa2Nb3O10 powders, and on Ca2Nb3O10- nanosheets revealed formation of local superstructures that are not detected by X-ray diffraction due to the weakness of superstructure reflection intensities. Nanosheets were deposited on substrates using the Langmuir-Blodgett method. A smooth covering of the surface was shown by atomic force microscopy. 200 nm thick KNbO3 films have been grown by pulsed laser deposition on Ca2Nb3O10--NS/glass and on (001)SrTiO3 substrates for comparison. Substrates covered with nanosheets induced highly textured (001)-oriented thin film, which possesses a similar microstructure as epitaxial film on single crystalline strontium titanate substrate.
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  • Influence of the synthesis media in the properties of CuO obtained by microwave-assisted hydrothermal method

    Maul, J.   Brito, A. S.   de Oliveira, A. L. M.   Lima, S. J. G.   Maurera, M. A. M. A.   Keyson, D.   Souza, A. G.   Santos, I. M. G.  

    Copper monoxide (CuO) was successfully obtained by microwave-assisted hydrothermal method, using different conditions-in a solution without base, in a solution alkalinized with NaOH or with NH(4)OH. The powders were analyzed by thermal analysis (TG/DTA), X-ray diffraction (XRD), infrared spectroscopy, UV-Visible spectroscopy, and scanning electronic microscopy. XRD results showed that CuO was obtained with monoclinic structure and without secondary phases. Thermal analysis and infrared spectra indicated the presence of acetate groups on the powder surface. TG curves also showed a mass gain assigned to the Cu(I) oxidation indicating that a reduction possibly occurred during synthesis. The high and broad absorption band in the UV-Vis spectroscopy from 250 to 750 nm indicated the coexistence of Cu(II) and Cu(I), confirming the Cu(II) reduction, inside the CuO lattice. It was also possible to confirm the Cu(II) reduction by a displacement of the Me-O vibration bands observed in the IR spectra at around 500 cm(-1).
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  • It\"s a Bird, It\"s a Plane, It\"s a Dilated Superhero

    Wanda Milliman  

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  • A Conversation with S. R. S. Varadhan

    Zeitouni, Ofer  

    Sathamangalam Ranga Iyengar Srinivasa (Raghu) Varadhan was born in Chennai (then Madras). He received his Bachelor's and Master's degree from Presidency College, Madras, and his PhD from the Indian Statistical Institute in Kolkata, in 1963. That same year he came to the Courant Institute, New York University as a postdoc, and remained there as faculty member throughout his career. He has received numerous prizes and recognitions, including the Abel Prize in 2007, the US National Medal of Science in 2010 and honorary degrees from the Chennai Mathematical Institute, Duke University, the Indian Statistical Institute, Kolkata and the University of Paris.
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  • A Conversation with S. R. S. Varadhan

    Zeitouni   Ofer  

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  • Sigma(s) - Sigma(s) as a Di-baryonic Molecule

    Rathaud, D. P.   Rai, Ajay Kumar  

    We study the Sigma(s) - Sigma(s) as a possible di-baryonic molecule in the potential model framework. We approximated the binding mechanism mainly as One Boson Exchange (OBE) plus screen type Yukawa potential. We predict the Sigma(s) - Sigma(s) bound state molecule with I/(J(P))=3D0(0(+)) and 0(1(+)) possible quantum numbers.
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  • Simpson\"s paradox: A statistician\"s case study

    Chu, Kevin H   Brown, Nathan J   Pelecanos, Anita   Brown, Anthony FT  

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  • A Revision of Cuphea section Amazoniana s. s. (Lythraceae)

    Graham, Shirley A.  

    Cuphea section Amazoniana, one of 13 sections in Cuphea, comprises 20 species, mostly narrow endemics in Colombia, Ecuador, and the Guiana Shield region of Venezuela, Guyana, French Guiana, and Brazil. The species inhabit river margins, tepuis, scrubland, savanna, and low montane forests in tropical to cold temperate climates. They are subshrubs defined by the common presence of a strigose indumentum of bifid (malpighiaceous) trichomes; small elliptic to narrowly lanceolate or linear coriaceous leaves; and tubular flowers to 9 mm long with 11 deeply inserted stamens included in the floral tube. In morphology, they are similar to or partially overlap species currently classified in Cuphea sections Trispermum and Heteranthus. The revision provides a new key, comparative morphological descriptions, first descriptions and illustrations of pollen and seed morphology, and distribution maps. Cuphea saxatilis S. A. Graham, sp. nov. from Colombia and Cuphea trisperma S. A. Graham, sp. nov. from Venezuela are newly described. Cuphea killipii Lourteig is placed in synonomy of C. philombria Lourteig. Presence or absence of a floral spur, position and shape of a nectary-like floral organ, the "disc", and presence of two major pollen types suggest the section is not monophyletic, but consists of a minimum of two phylogenetic lineages, one in the Guiana Shield region in Venezuela and eastward, the other in low montane forests and on outliers of the Guiana Shield in Colombia and northern Ecuador. Fossilized Cuphea pollen grains resembling two types of pollen known in sect. Amazoniana, establish the presence of the genus in the Mio-Pliocene to Holocene of northern South America in areas occupied today by members of the section.
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  • “Walcott’s Lament”

    Miller, Nancy Anne  

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  • A Wheel’s Life

    Wood, Nigel  

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  • Look! Up in the sky! It\"s a bird. It\"s a plane. It\"s a medical drone!

    The Lancet Haematology  

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