639 research outputs found

    Transposição de marcadores microssatélites derivados de mamona em tungue.

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    Entre as culturas oleaginosas, o tungue é uma alternativa de grande potencial econômico para o sul do Brasil por apresentar elevado rendimento de óleo. Embora genótipos introduzidos no Estado tenham demonstrado adaptação, é fundamental desenvolver um programa de melhoramento genético para a cultura, a fim de oferecer cultivares mais produtivas. Uma forma eficiente de auxiliar os programas de melhoramento é a análise da variabilidade genética por meio de marcadores moleculares. Muitos estudos têm mostrado que grande parte dos marcadores SSR encontrados numa espécie podem ser transferidos para espécies correlatas. Tanto a mamona (Ricinus communis L.) como o tungue (Aleurites fordii), pertencem à família Euphorbiaceae, o que pode facilitar a transposição de primers microssatélites de mamona para tungue. O presente trabalho teve como objetivo testar a transposição de marcadores microssatélites do genoma de mamona para tungue. Foram utilizados 74 pares de primers sintetizados a partir do genoma da mamona. Os resultados demonstram ser possível utilizar marcadores microssatélites em genótipos de tungue desenvolvidos a partir do genoma de mamona

    Variabilidade genética, respostas fisiológicas e morfoagronômicas para tolerância ao calor em batata

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    Tese (Doutorado) - Programa de Pós-Graduação em Agronomia. Universidade Federal de Pelotas, Pelotas. Orientadora: Caroline Marques Castro, Coorientador: Arione da Silva Pereira

    Spectroscopic follow up of arclets in AC114 with the VLT

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    We present the first results on the VLT/FORS-1 spectroscopic survey of amplified sources and multiple images in the lensing cluster AC114. Background sources were selected in the cluster core, close to the critical lines, using photometric redshifts combined with lensing inversion criteria. Spectroscopic results are given, together with a brief summary of the properties of some of these high-z galaxies.Comment: 4pages. To appear in the Proceedings of the XXth Moriond Astrophysics Meeting "Cosmological Physics with Gravitational Lensing", eds. J.-P. Kneib, Y. Mellier, M. Moniez and J. Tran Thanh Van, Les Arcs, France, March 11th-18th 200

    Keck Spectroscopy of Faint 3<z<8 Lyman Break Galaxies:- Evidence for a Declining Fraction of Emission Line Sources In the Redshift Range 6<z<8

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    Using deep Keck spectroscopy of Lyman break galaxies selected from infrared imaging data taken with WFC3/IR onboard the Hubble Space Telescope, we present new evidence for a reversal in the redshift-dependent fraction of star forming galaxies with detectable Lyman alpha emission in the redshift range 6.3 < z < 8.8. Our earlier surveys with the DEIMOS spectrograph demonstrated a significant increase with redshift in the fraction of line emitting galaxies over the interval 4 < z < 6, particularly for intrinsically faint systems which dominate the luminosity density. Using the longer wavelength sensitivities of LRIS and NIRSPEC, we have targeted 19 Lyman break galaxies selected using recent WFC3/IR data whose photometric redshifts are in the range 6.3 < z < 8.8 and which span a wide range of intrinsic luminosities. Our spectroscopic exposures typically reach a 5-sigma sensitivity of < 50 A for the rest-frame equivalent width (EW) of Lyman alpha emission. Despite the high fraction of emitters seen only a few hundred million years later, we find only 2 convincing and 1 possible line emitter in our more distant sample. Combining with published data on a further 7 sources obtained using FORS2 on the ESO VLT, and assuming continuity in the trends found at lower redshift, we discuss the significance of this apparent reversal in the redshift-dependent Lyman alpha fraction in the context of our range in continuum luminosity. Assuming all the targeted sources are at their photometric redshift and our assumptions about the Lyman alpha EW distribution are correct, we would expect to find so few emitters in less than 1% of the realizations drawn from our lower redshift samples. Our new results provide further support for the suggestion that, at the redshifts now being probed spectroscopically, we are entering the era where the intergalactic medium is partially neutral.Comment: 8 pages, 5 figures, Accepted to ApJ 10/1/1
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