1,453 research outputs found

    Rank two quadratic pairs and surface group representations

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    Let XX be a compact Riemann surface. A quadratic pair on XX consists of a holomorphic vector bundle with a quadratic form which takes values in fixed line bundle. We show that the moduli spaces of quadratic pairs of rank 2 are connected under some constraints on their topological invariants. As an application of our results we determine the connected components of the SO0(2,3)\mathrm{SO}_0(2,3)-character variety of XX.Comment: 37 pages, 1 figur

    The Effect Of Dye-polymer Interactions On The Kinetics Of The Isomerization Of 4-dimethyl-aminoazobenzene And Mercury Dithizonate

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    Thermal and photo-isomerization reactions of mercury dithizonate and 4-dimethyl-aminoazobenzene were studied in solutions and in polymer matrices. We used exponential functions to calculate the rate constants for both processes. The kinetic behavior was well described by monoexponential functions for these dyes dissolved in solvents, although bi-exponential functions are required when these dyes are dissolved in polymers. The rate constants are strongly influenced by dye/solvent and dye/polymer interactions, as well as by the aging processes of the polymer matrix. In general, the reaction is faster in more polar mediums, solvents or polymer matrices, since stabilization of different tautomers takes place. We also showed that larger molecules isomerize slowly and slower isomerization has also been observed for annealed samples. Both results are attributed to the importance of free-volumes in polymeric matrices.152253261Natansohn, A., Rochon, P., (2002) Chem. 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Am., B7, p. 842Viswanathan, N.K., Kim, D.Y., Bian, S., Williams, J., Liu, W., Li, L., Samuelson, L., Tripathy, S., (1999) J. Mater. Chem., 9, p. 1941Delaire, J.A., Nakatani, K., (2000) Chem. Rev., 100, p. 1817Delaire, J.A., Ishow, E., Nakatani, K., (2002) Photoreactive Organic Thin Films, p. 306. , Sekkat, Z.Knoll, W., eds., Academic Press: AmsterdamMendonça, C.R., Dhanabalan, A., Balogh, D.T., Misoguti, L., Dos Santos Jr., D.S., Pereira-da-Silva, M.A., Giacometti, J.A., Oliveira Jr., O.N., (1999) Macromolecules, 32, p. 1493Mendonça, C.R., Dos Santos Jr., D.S., Balogh, D.T., Dhanabalan, A., Giacometti, J.A., Zilio, S.C., Oliveira Jr., O.N., (2001) Polymer, 42, p. 6539Oliveira Jr., O.S., Li, L., Kumar, J., Tripathy, S.K., (2002) Photoreactive Organic Thin Films, p. 429. , Sekkat, Z.Knoll, W. eds.Academic Press: AmsterdamDhanabalan, A., Dos Santos Jr., D.S., Mendonça, C.R., Misoguti, L., Balogh, D.T., Giacometti, J.A., Zílio, S.C., Oliveira Jr., O.N., (1999) Langmuir, 15, p. 4560Ichimura, K., (2000) Chem. Rev., 100, p. 1847Richardson, T.M., (2000) Functional Organic and Polymeric Materials, , John Wily&Sons. Ltd.: ChilchesterWang, C., Weiss, R.G., (1999) Macromolecules, 32, p. 7032Yamaki, S.B., Atvars, T.D.Z., Weiss, R.G., (2002) Photochem. Photobiol. Sci., 1, p. 649Sekkat, Z., Dumont, M., (1992) Appl. Phys. B, 54, p. 486Talhavini, M., Atvars, T.D.Z., Schurr, O., Weiss, R.G., (1998) Polymer, 39, p. 3221Talhavini, M., Atvars, T.D.Z., Cui, C., Weiss, R.G., (1996) Polymer, 37, p. 4365Airinei, A., Buruiana, E.C.J.M.S., (1994) Pure Appl. Chem., A31, p. 1233Kryszewski, M., Nadolski, B., North, A.M., Pethrick, R.A., (1980) J. Chem. Soc., Faraday Trans. 2, 76, p. 351Haitjema, H.J., Von Morgan, G.L., Tan, Y.Y., Challa, G., (1995) Macromolecules, 28, p. 2867Nayak, B., Gupta, S.N., (1995) J. Polym. Sci.: Part B: Polym. Phys., 31, p. 1529Petersen, R.L., Harris, G.L., (1985) J. Chem. Educ., 62, p. 802Meriwether, L.S., Breitner, E.C., Sloan, C.L., (1965) J. Am. Chem. Soc., 87, p. 4441Meriwether, L.S., Breitner, E.C., Colthup, N.B., (1965) J. Am. Chem. 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Dissertation, Universidade Estadual de Campinas, BrazilDe Oliveira, M.G., (1992), PhD Thesis, Universidade Estadual de Campinas, BrazilWang, C.L., Hirade, T., Maurer, F.H.J., Eldrup, M., Pedersen, N.J., (1998) J. Chem. Phys., 108, p. 4654Victor, J.G., Torkelson, J.M., (1997) Macromolecules, 20, p. 2241Turi, E.A., (1981) Thermal Characterization of Polymeric Materials, , Academic: Orlando(1998) Gaussian 98 (Revision A.1), , Gaussian, Inc.: Pittsburgh, P

    A 2d Honeycomb Photonic Crystal Under Applied Magnetic Fields

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    The band-structure properties of a photonic two-dimensional honeycomb lattice formed by cylindrical semiconductor shell rods with dielectric permitivities ε 1 and ε 2, and embedded in a background with permitivity ε 3, is studied by using an standard plane-wave expansion. The properties of bandgaps and density of states, considering dispersive dielectric responses, are investigated together with the possibility of fabricating systems with tunable photonic bandgaps, due to the Voigt magneto-optical effect, under the influence of an external magnetic field. © 2008 SPIE.7138J. D. Joannopoulos, R. D. Meade, J. N. Winn, Photonic Crystals: Molding the Flow of Light, Princeton University Press, Princeton, 1995E. Istrate and E. H. Sargent, Rev. Mod. Phys. 78, 455 (2006)Xu, C., Hu, X., Li, Y., Liu, X., Fu, R., Zi, J., (2003) Phys. Rev. B, 68, p. 193201Kee, C.-S., Kim, J.-E., Park, H.Y., Park, I., Lim, H., (2000) Phys. Rev. B, 61, p. 15523Anderson, C.M., Giapis, K.P., (1996) Phys. Rev. Lett, 77, p. 2949Rezaei, B., Kalafi, M., (2006) Optics Commun, 266, p. 159Busch, K., John, S., (1999) Phys. Rev. Lett, 83, p. 967S. B. Cavalcanti, M. de Dios-Leyva, E. Reyes-Gómez, and L. E. Oliveira, Phys. Rev. B 74, 153102 (2006)ibid., Phys. Rev. E 75, 026607 (2007)Ho, K.M., Chan, C.T., Soukoulis, C.M., (1990) Phys. Rev. Lett, 65, p. 315

    Restructuring Passiflora Cincinnata Fruit Pulp: Influence Of Hydrocolloids [estruturação De Polpa De Passiflora Cincinnata: Influência De Hidrocoloides]

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    This study evaluated the effect of mixtures of alginate, low methoxy pectin and gelatin on characteristics of P. cincinnata fruit gels, containing pulp with high soluble solids content (50 °Brix). The results of a central composite design showed that the models obtained, except for water activity and pH, were predictive. Gelatin was an important factor affecting firmness and colour parameters since higher concentrations of this hydrocolloid, combined with alginate concentrations greater than 1.3% and pectin quantity up to 1.26%, could be used to obtain clear yellow products with firmness greater that 1.2 kg.311160166(2000) Official methods of analysis of the Association of Official Analytical Chemists International, , ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS-AOAC, 17th ed. Arlington: AOACAmeny, M.A., Wilson, P.W., Relationship between hunter color values and beta carotene contents in white-fleshed African sweet potatoes (Ipomoea batatas Lam.) (1997) Journal of the Science of Food and Agriculture, 73, pp. 301-306Araújo, F.P., Caracterização de frutos de maracujá do mato (Passiflora cincinnata Mast.) cultivado em condições de sequeiro (2002) Congresso Nacional de Botânica, 53, p. 10. , In:, Recife. Resumos... São Paulo: Sociedade Botânica do Brasil, 2002Araújo, F.P., Estratégias para coleta de germoplasma de maracujá do mato (Passiflora cincinnata Mast.) (2006) Magistra, 18, pp. 35-37Bruckner, C.H., Picanço, M.C., (2001) Maracujá: Tecnologia de produção, pós-colheita, agroindústria e mercado, , Porto Alegre: Cinco ContinentesCervi, A.C., (1997) Passifloraceae do Brasil. Estudo do gênero Passiflora L., subgênero Passiflora, , Madrid: FontqueiraChirife, J., Buera, M.D.P., Water activity, glass transition and microbial stability in concentrated/semi moisture food systems (1994) Journal of Food Science, 59, pp. 925-927Gill, B.S., Effects of oBrix, sodium alginate and drying temperature on colour, texture and sensory properties of 'ushehari' mango leather (2004) International Journal of Food Science and Technology, 41, pp. 373-378Glicksman, M., The hydrocolloids industry in the 80's-problems and opportunities (1982) Progress in Food and Nutrition Science, 6, pp. 299-321Grizotto, R.K., Otimização via metodologia da superfície de resposta dos parâmetros tecnológicos para produção de fruta estruturada e desidratada a partir de polpa concentrada de mamão (2005) Ciência e Tecnologia de Alimentos, 25, pp. 158-164Grizotto, R.K., Technological aspects for restructuring concentrated pineapple pulp (2007) Lebensmittel-Wissenschaft und-Technologie, 5, pp. 759-765Laboissière, L.H.E.S., Effect of high hydrostatic pressure (HHP) on sensory characteristics of yellow passion fruit juice (2007) Innovative Food Science and Emerging Technologies, 8, pp. 469-477Mancini, F., McHugh, T.H., Fruit-alginate interactions in novel restructured products (2000) Nahrung, 44, pp. 152-157Mouquet, C., Dumas, J.C., Guilbert, S., Texturization of sweetened mango pulp: Optimization using Response Surface Methodology (1992) Journal of Food Science, 6, pp. 1395-1400Nunes, T.S., de Queiroz, L.P., A família Passifloraceae na Chapada da Diamantina, Bahia, Brasil (2001) Sitientibus-Séries Ciências Biológicas, 1, pp. 33-46Olivier, D., Guigou, B., Bouillette, T., (1998) Produit alimentaire reconstitué, procede et mélanger pour sa préparation, , EP 0274301 AlRodrigues, M.I., Iemma, A.F., (2005) Planejamento e otimização de processos: Uma estratégia seqüencial de planejamentos, p. 326. , Campinas: Casa do Pão EditoraTenn, F.E., (1985) Fruit filler for pastry products and process for its preparation, , US 4562080Sass-Kiss, A., Differences in anthocyanin and carotenoid content of fruits and vegetables (2005) Food Research International, 38, pp. 1023-1029(1995) Computer program manual, , STATISTICA for Windows 5.0, Tulsa: StatSoft In

    Uso De água Residuária Da Piscicultura No Cultivo De Alface

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    Lettuce stands out as the main leafy vegetable consumed in Brazil, with divergence regarding adaptability to different environmental conditions, which include salinity. The objective of the work was to evaluate the response of lettuce cultivars to the use of saline wastewater from fish farming. The experiment was conducted in a completely randomized design with four replicates, in a factorial 7 × 4, corresponding to seven cultivars (Regiane, Vera, Isabela, Elisa, Amelia, Lavinia and Angelina) and four salt concentrations (1.2, 2.2, 3.2 and 4.2 dS m-1). The evaluated characteristics were: number of leaves, leaf area, crown diameter and shoot fresh and dry matter. Diluted wastewater from fish farming can be used in the preparation of solution for fertigation of lettuce. The cultivars Regiane and Elisa had higher production of leaves and leaf area, while Amélia and Angelina were the most productive in terms of biomass. The cultivars Vera, Isabela, Amélia and Angelina were more tolerant to the salinity of the fertigation solution. © 2016, Departamento de Engenharia Agricola - UFCG/Cnpq. All rights reserved.20872873

    Relationship between polymorphism of growth hormone and precocity traits in Nellore heifers

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    Avaliaram-se as relações entre o polimorfismo do gene do hormônio do crescimento (GH) e as características de precocidade, em novilhas da raça Nelore. Amostras de sangue periférico foram obtidas de 181 animais de três rebanhos distintos do estado da Bahia, nas quais foi realizada a extração de DNA e a amplificação por PCR, seguidas por digestão com enzima de restrição AluI. Os fragmentos resultantes da digestão enzimática foram analisados em gel de agarose 2% para determinação dos respectivos genótipos. A frequência do alelo Leu nas amostras analisadas foi estimada em 100%. Em decorrência da alta incidência de homozigose para o alelo Leu, sugere-se que o restriction fragment lenght polymorphism AluI do gene GH não possa ser considerado como marcador molecular para precocidade sexual em novilhas Nelore nesses rebanhos.The relationships between polymorphism of growth hormone gene (GH) and precocity traits in Nellore heifers were evaluated. A total of 181 animals from three different farms of Bahia state, Brazil, were blood sampled. The DNA of each animal was extracted, amplified by PCR, and digested by "AluI" restriction enzyme, and the resultant fragments were analyzed in 2% agarose gel for genotype identification. The frequency of Leu allele in the analyzed samples was estimated in 100%. Due to the high incidence of homozygose for the Leu allele, it is suggested that the restriction fragment lenght polymorphism AluI of GH gene can not be considered as a molecular marker for sexual precocity in Nellore heifers of those herds.Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Mechanical and microstructural properties of redispersible polymer-gypsum composites

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    Studies on gypsum modified by polymers have been conducted to assess the potential of improvement in the mechanical performance, water resistance and increasing the setting time, facilitating its handling. Gypsum-based compounds made with different additions of redispersible polymers were studied, such as: ethylene-vinyl acetate (EVA), vinyl acetate terpolymer, vinyl laurate and vinyl chloride (VA/VL/VC), and vinyl acetate and vinyl versatate (VA/VeoVA). The influence on setting time, microstructural formation and on the bending performance was assessed, as well as and compression of the hardened gypsum. The composites were prepared using a polymer concentration of 5% and 10%, and water/gypsum ratio of 0.6. The addition of the polymer decreased the structural robustness and change in the microstructure. We concluded that the reduction in the amount of water through additives may allow a more complete and robust training of gypsum crystals and compounds with better mechanical performance223COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESnão te

    A Taste Of Photonics: Band Structure, Null Gaps, Non-bragg Gaps, And Symmetry Properties Of One-dimensional Superlattices

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    We have investigated the propagation of plane waves through one-dimensional superlattices composed of alternate layers characterized by two different refractive indexes, which may take on positive as well as negative values. For both indices of refraction positive we have found null-gap points for commensurate values of the optical path lengths of each layer at which the superlattice becomes transparent. We have determined the symmetry properties of the electromagnetic field demonstrating the degeneracy of the solutions at these points. Furthermore, we have been able to characterize non-Bragg gaps that show up in frequency regions in which the average refractive index is null, by obtaining analytically the non-Bragg gap width which depends only on the ratio b/a of the layer widths.6726Rayleigh, L., (1887) Phil. Mag, 24 (256), p. 5. , SVeselago, V.G., (1968) Sov. Phys. Usp, 10, p. 509Parimi, P.V., Lu, W.T., Vodo, P., Sridhar, S., (2003) Nature, 426, p. 404Cubuku, E., Aydin, K., Ozbay, E., Foteinopolou, S., Soukoulis, C.M., (2003) Phys. Rev. Lett, 91, p. 207401Yeh, P., Yariv, A., Hong, C.-S., (1977) J. Opt. Soc. Am, 67, p. 423Cavalcanti, S.B., de Dios-Leyva, M., Reyes-Gómez, E., Oliveira, L.E., (2006) Phys. Rev. B, 74, p. 153102(2007) Phys. Rev. E, 75, p. 026607Eleftheriades, G.V., Yyer, A.K., Kremer, P.C., (2002) IEEE Trans. Microwave Theory Tech, 50, p. 2702Li, J., Zhou, L., Chan, C.T., Sheng, P., (2003) Phys. Rev. Lett, 90, p. 08390

    Family Health Development in Life Course Research: A Scoping Review of Family Functioning Measures

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    BACKGROUND AND OBJECTIVES: Our objective is to identify common family functioning measurement tools and assess their compatibility with family-health development and life-course perspectives. METHODS: Data sources include PubMed, ERIC, CINAHL, Families and Societies Worldwide, PsychInfo, Web of Science, PsychNet, and Health and Psychosocial Instruments. Title and abstract screening and full-text review of articles were conducted by multiple reviewers based on prespecified inclusion criteria. Data extraction focused on features of identified measurements tools, including: (1) name (2) domains of family functioning measured, (3) established psychometric properties, and (4) original context of psychometric evaluation (eg, details about the study sample). RESULTS: Of the 50 measurement tools identified, 94% measured organizational patterns (eg, flexibility, connectedness, or resources), 46% measured belief systems (eg, making meaning of adversity, or positive outlook), and 54% measured communication processes (eg, open emotional sharing, or collaborative problem-solving). CONCLUSIONS: Existing measures of family functioning can aid life-course researchers in understanding family processes as contexts for health and well-being. There also remain opportunities to refine or develop measures of family functioning more compatible with a life-course perspective that assess family processes (1) at various life stages; (2) with various backgrounds, identities, structures, and experiences; and (3) embedded in or impacted by various contexts that may facilitate or hinder family functioning
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