26,666 research outputs found

    Produção de mudas micropropagadas de bananeira.

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    O objetivo desta publicação é fornecer informações para a produção de mudas micropropagadas de bananeira, em larga escala.bitstream/item/72455/1/CIT12001.pd

    Cosmological scenarios from multiquintessence

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    In this work we derive and analyse cosmological scenarios coming from multi-component scalar field models. We consider a direct sum of a sine-Gordon with a Z2 model, and also a combination of those with a BNRT model. Moreover, we work with a modified version of the BNRT model, which breaks the Z2 x Z2 symmetry of the original BNRT potential, coupled with the sine-Gordon and with the standard Z2 models. We show that our approach can be straightforwardly elevated to NN fields. All the computations are made analytically and some parameters restriction is put forward in order to get in touch with complete and realistic cosmological scenarios

    Constraining the evolution of the CMB temperature with SZ measurements from Planck data

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    The CMB temperature-redshift relation, T_CMB(z)=T_0(1+z), is a key prediction of the standard cosmology, but is violated in many non standard models. Constraining possible deviations to this law is an effective way to test the LambdaCDM paradigm and to search for hints of new physics. We have determined T_CMB(z), with a precision up to 3%, for a subsample (104 clusters) of the Planck SZ cluster catalog, at redshift in the range 0.01-- 0.94, using measurements of the spectrum of the Sunyaev Zel'dovich effect obtained from Planck temperature maps at frequencies from 70 to 353 GHz. The method adopted to provide individual determinations of T_CMB(z) at cluster redshift relies on the use of SZ intensity change, Delta I_SZ(nu), at different frequencies, and on a Monte-Carlo Markov Chain approach. By applying this method to the sample of 104 clusters, we limit possible deviations of the form T_CMB(z)=T_0(1+z)^(1-beta) to be beta= 0.022 +/- 0.018, at 1 sigma uncertainty, consistent with the prediction of the standard model. Combining these measurements with previously published results we get beta=0.016+/-0.012.Comment: submitted to JCAP, 21 pages, 8 figure

    Artificial light and growth regulators on the in vitro etiolation of Cattleya labiata.

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    Made available in DSpace on 2018-01-18T22:15:11Z (GMT). No. of bitstreams: 1 ART17088.pdf: 109805 bytes, checksum: 23bcb913384e6bcd8b2295e502a6ff88 (MD5) Previous issue date: 2018-01-15bitstream/item/171365/1/ART17088.pd

    On the Uq[sl(2)]{\cal{U}}_{q}[sl(2)] Temperley-Lieb reflection matrices

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    This work concerns the boundary integrability of the spin-s Uq[sl(2)]{\cal{U}}_{q}[sl(2)] Temperley-Lieb model. A systematic computation method is used to constructed the solutions of the boundary Yang-Baxter equations. For ss half-integer, a general 2s(s+1)+3/22s(s+1)+3/2 free parameter solution is presented. It turns that for ss integer, the general solution has 2s(s+1)+12s(s+1)+1 free parameters. Moreover, some particular solutions are discussed.Comment: LaTex 17 page

    Constraining the redshift evolution of the Cosmic Microwave Background black-body temperature with PLANCK data

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    We constrain the deviation of adiabatic evolution of the Universe using the data on the Cosmic Microwave Background (CMB) temperature anisotropies measured by the {\it Planck} satellite and a sample of 481 X-ray selected clusters with spectroscopically measured redshifts. To avoid antenna beam effects, we bring all the maps to the same resolution. We use a CMB template to subtract the cosmological signal while preserving the Thermal Sunyaev-Zeldovich (TSZ) anisotropies; next, we remove galactic foreground emissions around each cluster and we mask out all known point sources. If the CMB black-body temperature scales with redshift as T(z)=T0(1+z)1αT(z)=T_0(1+z)^{1-\alpha}, we constrain deviations of adiabatic evolution to be α=0.007±0.013\alpha=-0.007\pm 0.013, consistent with the temperature-redshift relation of the standard cosmological model. This result could suffer from a potential bias δα\delta\alpha associated with the CMB template, that we quantify it to be δα0.02|\delta\alpha|\le 0.02 and with the same sign than the measured value of α\alpha, but is free from those biases associated with using TSZ selected clusters; it represents the best constraint to date of the temperature-redshift relation of the Big-Bang model using only CMB data, confirming previous results.Comment: ApJ, in press. Manuscript matches the accepted version: 10 pages, 7 figures, 3 table

    Nonlinear viscosity and velocity distribution function in a simple longitudinal flow

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    A compressible flow characterized by a velocity field ux(x,t)=ax/(1+at)u_x(x,t)=ax/(1+at) is analyzed by means of the Boltzmann equation and the Bhatnagar-Gross-Krook kinetic model. The sign of the control parameter (the longitudinal deformation rate aa) distinguishes between an expansion (a>0a>0) and a condensation (a<0a<0) phenomenon. The temperature is a decreasing function of time in the former case, while it is an increasing function in the latter. The non-Newtonian behavior of the gas is described by a dimensionless nonlinear viscosity η(a)\eta^*(a^*), that depends on the dimensionless longitudinal rate aa^*. The Chapman-Enskog expansion of η\eta^* in powers of aa^* is seen to be only asymptotic (except in the case of Maxwell molecules). The velocity distribution function is also studied. At any value of aa^*, it exhibits an algebraic high-velocity tail that is responsible for the divergence of velocity moments. For sufficiently negative aa^*, moments of degree four and higher may diverge, while for positive aa^* the divergence occurs in moments of degree equal to or larger than eight.Comment: 18 pages (Revtex), including 5 figures (eps). Analysis of the heat flux plus other minor changes added. Revised version accepted for publication in PR

    Influência do preparo do solo, sistema de plantio e porta-enxerto no crescimento de limeira ácida 'tahiti' em tabuleiro costeiro da Bahia - 2ª etapa.

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    Na Bahia, 80% da área citrícola encontra-se na Grande Unidade de Paisagem Tabuleiros Costeiros, em propriedades de até dez hectares (agricultura familiar). Objetiva-se um modelo de manejo que possibilite sustentabilidade, menor relação custo/benefício e maior produtividade de pomares cítricos especialmente destinados a essas propriedades. O experimento foi instalado na Fazenda Lagoa do Coco, município de Rio Real, Litoral Norte do Estado da Bahia, em um Argissolo Amarelo Coeso. O delineamento experimental é inteiramente casualizado, no esquema de parcelas sub-subdivididas no espaço, com seis repetições. Nas parcelas constam dois sistemas de preparo do solo (convencional, isto é, aração a 0, 25 m de profundidade, e aração seguida de subsolagem nas linhas de plantio a 0,50 m de profundidade); nas sub-parcelas constam dois sistemas de plantio (convencional, isto é, plantio de mudas, e semeadura e enxertia no local definitivo); nas sub-parcelas constam cinco porta-enxertos enxertados com limeira ácida 'Tahiti': limoeiro 'Cravo', limoeiro 'Volkameriano', tangerineira 'Sunki Tropical', tangerineira 'Cleópatra' e híbrido TSK x TRENG 256. Observou-se que o crescimento das plantas originárias da semeadura do porta enxerto cítrico no local definitivo é superior ao daquelas originárias de mudas, independentemente do preparo do solo e da combinação copa/porta-enxerto
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