1,736 research outputs found

    Disentangling the near infrared continuum spectral components of the inner 500 pc of Mrk 573: two-dimensional maps

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    We present a near infrared study of the spectral components of the continuum in the inner 500×\times500 pc2^2 of the nearby Seyfert galaxy Mrk573 using adaptive optics near-infrared integral field spectroscopy with the instrument NIFS of the Gemini North Telescope at a spatial resolution of \sim50 pc. We performed spectral synthesis using the {\sc starlight} code and constructed maps for the contributions of different age components of the stellar population: young (age100age\leq100 Myr), young-intermediate (100<age700100<age\leq700 Myr), intermediate-old (700700 Myr 22 Gyr) to the near-IR K-band continuum, as well as their contribution to the total stellar mass. We found that the old stellar population is dominant within the inner 250 pc, while the intermediate age components dominate the continuum at larger distances. A young stellar component contributes up to \sim20% within the inner \sim70 pc, while hot dust emission and featureless continuum components are also necessary to fit the nuclear spectrum, contributing up to 20% of the K-band flux there. The radial distribution of the different age components in the inner kiloparsec of Mrk573 is similar to those obtained by our group for the Seyfert galaxies Mrk1066, Mrk1157 and NGC1068 in previous works using a similar methodology. Young stellar populations (\leq100 Myr) are seen in the inner 200-300 pc for all galaxies contributing with \ge20% of the K-band flux, while the near-IR continuum is dominated by the contribution of intermediate-age stars (t=t=100 Myr-2 Gyr) at larger distances. Older stellar populations dominate in the inner 250 pc

    Sample size for family evaluation in potato breeding programs.

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    Clonal families from a broad genetic base population in the Potato Breeding Program at the Universidade Federal de Lavras (UFLA), Brazil, were used in this trials. Twenty-five families were assessed in a 5 x 5 triple lattice design. Each plot consisted of 30 clones distributed in three rows of ten plants. Tuber yield per plant, percentage of large tubers, mean weight of large tubers, mean medium-sized tuber weight and tuber specific gravity were measured. Three hundred experiments were simulated varying the family sizes from three to 90 clones. The coefficients of experimental variation (CVe), the coefficients of genetic variation (CVg), heritabilities for family mean and the CVg/CVe ratio were estimated. Genetic parameters were stabilized with family sizes as small as six clones, depending on the trait. This indicates that the families can be adequately represented by a small sample of clones. Using the maximum curvature method it is possible to conclude that approximately 30 clones would be sufficient to represent each family, even for traits with the highest CVe. The genetic variance within family was greater than the genetic variance among families for all traits, indicating a favorable potential for within family selection. The correlation coefficients of the family means with the 5%, 10%, 15% and 20% best clones from each family, considering the five traits assessed, were always high, meaning that within the best families generally are the best clones

    Seasonal proteome variation in intertidal shrimps under a natural setting: connecting molecular networks with environmental fluctuations

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    The ability of intertidal organisms to maintain their performance via molecular and physiological adjustments under low tide, seasonal fluctuations and extreme events ultimately determines population viability. Analyzing this capacity in the wild is extremely relevant since intertidal communities are under increased climate variability owing to global changes. We addressed the seasonal proteome signatures of a key intertidal species, the shrimp Palaemon elegans, in a natural setting. Shrimps were collected during spring and summer seasons at low tides and were euthanized in situ. Environmental variability was also assessed using hand-held devices and data loggers. Muscle samples were taken for 2D gel electrophoresis and protein identification through mass spectrometry. Proteome data revealed that 55 proteins (10.6% of the proteome) significantly changed between spring and summer collected shrimps, 24 of which were identified. These proteins were mostly involved in cytoskeleton remodelling, energy metabolism and transcription regulation. Overall, shrimps modulate gene expression leading to metabolic and structural adjustments related to seasonal differences in the wild (i.e. abiotic variation and possibly intrinsic cycles of reproduction and growth). This potentially promotes performance and fitness as suggested by the higher condition index in summer-collected shrimps. However, inter-individual variation (% coefficient of variation) in protein levels was quite low (min-max ranges were 0.6-8.3% in spring and 1.2-4.8% in summer), possibly suggesting reduced genetic diversity or physiological canalization. Protein plasticity is relevant to cope with present and upcoming environmental variation related to anthropogenic forcing (e.g. global change, pollution) but low inter-individual variation may limit evolutionary potential of shrimp populations.publishe

    Acúmulo e eficiência de uso de nutrientes na parte aérea de Eucalyptus urograndis em plantios puros e mistos com Acacia mangium Willd.

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    O plantio misto de eucalipto com Acacia mangium pode promover alterações no acúmulo de biomassa e na eficiência de uso de nutrientes (EUN) pelo eucalipto. Entretanto, tais alterações dependem do arranjo de plantio dessas espécies. O objetivo desse estudo foi avaliar o acúmulo de biomassa e a EUN na parte aérea do eucalipto, em plantios puros e mistos com A. mangium. Localizado em Seropédica, RJ, o experimento avaliou 4 arranjos de plantio: eucalipto puro 3x3 m (E100); eucalipto puro + ureia 3x3 m (E100+N); plantios mistos 3x3 m (A50:E50) e 3x1,5 m (A100:E100). Nos plantios mistos a espécie leguminosa foi intercalada ao eucalipto na linha de plantio. A biomassa de frações da parte aérea foi estimada aos 30 meses de idade por inventário florestal e modelos alométricos elaborados para este experimento. A EUN foi estimada pelo cálculo do coeficiente de utilização biológica (CUB). Os arranjos com maiores acúmulos de biomassa aérea de eucalipto foram E100+N e A50:E50 (com densidade de árvores igualada aos demais tratamentos). No entanto, E100+N apresentou baixos valores de CUB, enquanto que em A50:E50 esses valores foram de 3 a 6 vezes maiores que nos demais tratamentos. O arranjo A100:E100 não diferiu de E100 quanto à produção de biomassa de eucalipto, mas também apresentou valores de CUB superiores. Esses resultados sugerem a ocorrência de interações de facilitação e complementariedade no plantio misto do eucalipto com A. mangium. A alta EUN do eucalipto no arranjo A50:E50 indica o alto potencial de uso desse sistema de produção em solos de baixa fertilidade

    Produtividade de milho para ensilagem e feijão-miúdo em cultivo consorciado no noroeste do Rio Grande do Sul.

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    A bovinocultura de leite no noroeste do Rio Grande do Sul está em expansão e vem se mostrando uma alternativa rentável para pequenas propriedades. O feijão-miúdo é uma leguminosa tropical que vem se difundindo rapidamente, porém informações sobre seu cultivo e potencial de uso são escassos. O objetivo deste trabalho é avaliar a produtividade de milho para ensilagem e de feijão-miúdo em cultivo consorciado no noroeste do Rio Grande do Sul. Os tratamentos foram quatro variedades de feijão-miúdo cultivadas em consórcio com milho para ensilagem. Foram determinadas a estatura e a densidade real de plantas e as produções de massas verde e seca de milho e de feijão-miúdo na ocasião da colheita do milho. Não foram verificadas diferenças estatísticas nas variáveis analisadas, devido, provavelmente, aos altos coeficientes de variação obtidos. Foram encontrados valores expressivos de produções de massas verde e seca de milho, apesar de a densidade real de plantas de milho ter sido inferior à recomendada. As produções de massas verde e seca das variedades de feijão-miúdo ficaram aquém das obtidas em outras pesquisas regionais, sendo explicadas pela baixa densidade populacional no cultivo consorciado, época tardia de semeadura e avaliação de apenas um corte. A produção de forragem não foi afetada pelas variedades da leguminosa. O consórcio de milho e feijão-miúdo tem desempenho satisfatório e é uma alternativa na composição de sistemas de produção mais sustentáveis e racionais
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