Fontes e doses de adubo nitrogenado na avaliação do estado nutricional em mamão.

A adubação é um aspecto decisivo na produção de mudas sadias e bem nutridas. Um dos nutrientes quantitativamente mais importantes na adubação é o nitrogênio, que deve ser fornecido em dose apropriada e que pode variar dependendo do tipo de adubo a ser usado. Com o intuito de avaliar a fonte e a dose mais adequada de adubação nitrogenada para as mudas de mamoeiro, foram testados dois adubos (uréia e nitrato de amônio) e doses de nitrogênio. Para isso foi desenvolvido um experimento em condições de casa de vegetação, com vasos preenchidos com Latossolo Vermelho com 7 tratamentos (2 adubos x 3 doses de N + testemunha) e 4 repetições, perfazendo um total de 28 unidades experimentais. Cada unidade experimental foi composta por um vaso com 3 dm3 de solo, onde foram semeadas 4 sementes, com posterior raleamento mantendo uma planta por vaso. As doses consistiram na aplicação dos adubos equivalentes a: D1 = 150 mg; D2 = 300 mg e D3 = 450 mg dm3 de N, além da testemunha. As fontes utilizadas foram o nitrato de amônio e a uréia. A condução das mudas se deu por 90 dias, quando foram avaliados o teor de N nas folhas, massa de matéria seca nas folhas e total, além do acúmulo de N nas folhas e leitura do índice SPAD. O nitrato de amônio foi superior em relação à uréia para acúmulo foliar de N. Para N nas folhas as melhores doses foram a de 300 e 450 mg dm-3

The contribution of everyday activities for investigative practices for soil study

Studies in the Science education area reveal that investigative activities play a significant role in both, the student´s\ud and teacher´s learning process. This study evaluates investigative activities in the continuing education of teachers in the\ud schools of São Paulo from two assumptions: (1) the teaching of soils is difficult in urban areas because they are usually\ud covered. (2) investigative activities are essential for the teaching of soils. During previous studies related to teachers, we found\ud that they modify the activities suggested by researchers of Education in order to implement them in the classrooms. In order\ud to better understand how this knowledge is dissipated daily in the schools, we have conducted a new study with 4th grade\ud (now 5th year) elementary public school teachers. The results show that investigative activities improve student learning of\ud the content of soils, both in the acquisition of scientific skills such as the development of oral and writing abilities. The knowledge\ud surrounding the subject of soils changed as it became a formative element for students and teachers. Furthermore, the\ud activities triggered thematic teaching, breaking the fragmentation of knowledge and creating a more interconnected knowledgeEstudos na área de ensino de ciências revelam que as atividades investigativas exercem papel significativo\ud na aprendizagem, tanto de alunos, quanto de professores. Este trabalho avalia atividades investigativas na formação continuada\ud de professores nas escolas de São Paulo, a partir de dois pressupostos: (1) o ensino de solos é dificultado em área\ud urbana, onde ele está normalmente encoberto; (2) atividades investigativas são essenciais para ensino de solos. Durante\ud trabalho prévio com professores, constatamos que eles modificam as atividades sugeridas pelos pesquisadores de Educação,\ud ao implementá-las em sala de aula. Para entender melhor como tais saberes se mesclam cotidianamente nas escolas, realizamos\ud novo estudo com professores da 4ª série (atual 5º ano) do Ensino Fundamental em escola pública paulista. Os\ud resultados mostram que as atividades investigativas favoreceram a aprendizagem dos alunos sobre o conteúdo solos, tanto\ud na aquisição de habilidades científicas, como no desenvolvimento de oralidade e capacidade de redação. Transformou-se a\ud relação com o conhecimento acerca do solo, que se tornou elemento formativo para alunos e professores. Além disso, as atividades\ud desencadearam o ensino por temáticas, rompendo a fragmentação do conhecimento e tecendo conhecimento em redeCAPE

Efeito de doses de nitrogênio em cobertura em variáveis biométricas e de produção em híbridos de milho.

Resumo: Com o objetivo de avaliar a adubação nitrogenada em cobertura em variáveis biométricas e de produção de diferentes híbridos de milho, conduziu-se ensaio em condições de campo em Jaboticabal, SP. Antes da instalação do experimento foi realizada amostragem de solo na camada 0-20 cm para verificação da fertilidade do solo e ainda realizou-se a adubação de semeadura, que consistiu em 300 kg ha-1 do formulado 4-20-20. Os tratamentos foram dois genótipos híbridos simples, AS1522 e AS1596 submetidos a quatro níveis de N em cobertura: zero, metade da padrão, padrão e duas vezes a padrão. O delineamento foi em blocos ao acaso, com três repetições. A semeadura foi realizada manualmente, e quando as plantas atingiram estágio de maturidade fisiológica foram avaliadas as variáveis altura, diâmetro do colmo, produção de grãos, número de grãos por espiga e número de fileiras de grãos por espiga. Os dados foram analisados utilizando-se o teste F e, quando significativos foi realizado teste de comparação de médias. Há diferença entre os híbridos de milho em função das doses de nitrogênio aplicadas em cobertura para produção de grãos e eficiência agronômica. O material AS1596 apresentou superioridade na produção de grãos e eficiência agronômica em relação ao genótipo AS1522. [Effect of nitrogen topdressing levels on biometric variables and on production of corn hybrids]. Abstract: Aiming to evaluate the nitrogen topdressing on biometric variables and production of different corn hybrids, an experiment was conducted under field conditions in Jaboticabal, SP. Before carrying out the experiment, soil sampling in the layer 0-20 cm was performed for soil fertility verification, also it was performed the sowing fertilization, which consisted of the 300 kg ha-1 formulated 4-20-20. The treatments consisted of two simple hybrid genotypes, AS1522 and AS1596, subjected to four nitrogen level: zero, half the standard, standard and twice the standard. The experimental was a randomized complete block design with three replications. The sowing was done manually, and when the plants reached stage of physiological maturity, parameters such as height, stem geometry, grain yield, number of grains per spike and number of grain rows per ear were evaluated. The data were analyzed through the F test, and when significant, it was carried out an average comparison. There is difference between the hybrids on the basis of nitrogen topdressing for grain yield and agronomic efficiency. The material AS1596 showed superiority in grain yield and agronomic efficiency in relation to genotype AS1522

Nutrient accumulation curves in fruits and nutrient export by seeds and hulls harvesting of physic nut (Jatropha curcas L.).

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Chemical evolution of the Small Magellanic Cloud based on planetary nebulae

We investigate the chemical evolution of the Small Magellanic Cloud (SMC) based on abundance data of planetary nebulae (PNe). The main goal is to investigate the time evolution of the oxygen abundance in this galaxy by deriving an age-metallicity relation. Such a relation is of fundamental importance as an observational constraint of chemical evolution models of the SMC. We have used high quality PNe data in order to derive the properties of the progenitor stars, so that the stellar ages could be estimated. We collected a large number of measured spectral fluxes for each nebula, and derived accurate physical parameters and nebular abundances. New spectral data for a sample of SMC PNe obtained between 1999 and 2002 are also presented. These data are used together with data available in the literature to improve the accuracy of the fluxes for each spectral line. We obtained accurate chemical abundances for PNe in the Small Magellanic Cloud, which can be useful as tools in the study of the chemical evolution of this galaxy and of Local Group galaxies. We present the resulting oxygen versus age diagram and a similar relation involving the [Fe/H] metallicity based on a correlation with stellar data. We discuss the implications of the derived age-metallicity relation for the SMC formation, in particular by suggesting a star formation burst in the last 2-3 Gyr.Comment: 11 pages, 6 figures, accepted for publication in Astronomy and Astrophysic

Tatuagem: um mapa rizomático de um tema de pesquisa

A fim de compreender a dispersa produção da área interdisciplinar sobre a temática da tatuagem, realizamos um levantamento dos discursos de 35 artigos publicados em periódicos brasileiros da área interdisciplinar, no período compreendido entre 1990 e 2020. A partir desses artigos, elaboramos quatro eixos de análise: a tatuagem como inscrição do eu, potência criativa e emancipatória; o lado “b” da tatuagem; a interface entre saúde pública, dermatologia e tatuagem; e, por fim, a nova geração de tatuadores. Por fim, apresentamos algumas considerações no sentido de que, apreender a tatuagem como prática discursiva, abre as portas de um labirinto, cujas saídas inexistem e tampouco nos asseguram uma subjetividade contemporânea mais liberta e emancipada.To understand the dispersed interdisciplinary production on the topic of tattoos, we conducted a survey of the language of 35 articles published in Brazilian interdisciplinary journals from 1990 to 2020. From these articles, we developed four axes of analysis: tattoo as an inscription of the self, a creative and emancipatory power; the “B” side of tattoo; the interface between public health, dermatology and tattoo; and, lastly, the new generation of tattoo artists. We then present some considerations that apprehending tattoo as a discursive practice opens the doors of a labyrinth, whose exits do not exist and do not assure us a more liberated and emancipated contemporary subjectivity

In Search of Possible Associations between Planetary Nebulae and Open Clusters

We consider the possibility of cluster membership for 13 planetary nebulae that are located in close proximity to open clusters lying in their lines of sight. The short lifetimes and low sample size of intermediate-mass planetary nebulae with respect to nearby open clusters conspire to reduce the probability of observing a true association. Not surprisingly, line of sight coincidences almost certainly exist for 7 of the 13 cases considered. Additional studies are advocated, however, for 6 planetary nebula/open cluster coincidences in which a physical association is not excluded by the available evidence, namely M 1-80/Berkeley 57, NGC 2438/NGC 2437, NGC 2452/NGC 2453, VBRC 2 & NGC 2899/IC 2488, and HeFa 1/NGC 6067. A number of additional potential associations between planetary nebulae and open clusters is tabulated for reference purposes. It is noteworthy that the strongest cases involve planetary nebulae lying in cluster coronae, a feature also found for short-period cluster Cepheids, which are themselves potential progenitors of planetary nebulae.Comment: Accepted for publication in PASP (December 2007

Influence of nitrogen source and sucrose concentration on inulinase production by Kluyveromyces marxianus in fed-batch fermentation

This work studied the influence of nitrogen source and sucrose concentration in the feeding medium for biomass and inulinase production by Kluyveromyces marxianus var. bulgaricus. The results show that the best nitrogen source was a combination of 5 g/L of yeast extract and 10 g/L of peptone. Both cellular growth and enzymatic activity increased with sucrose concentration in the feeding medium (from 200 to 500 g/L). When the sucrose concentration reached 600 g/L, both cellular growth and enzymatic activity decreased.Key words: Kluyveromyces marxianus, nitrogen, sucrose, inulinase, fed-batch fermentation

An estimate of the time variation of the O/H radial gradient from planetary nebulae

Radial abundance gradients are a common feature of spiral galaxies, and in the case of the Galaxy both the magnitude of the gradients and their variations are among the most important constraints of chemical evolution models. Planetary nebulae (PN) are particularly interesting objects to study the gradients and their variations. Owing to their bright emission spectra, they can be observed even at large galactocentric distances, and the derived abundances are relatively accurate, with uncertainties of about 0.1 to 0.2 dex, particularly for the elements that are not synthesized in their progenitor stars. On the other hand, as the offspring of intermediate mass stars, with main sequence masses in the interval of 1 to 8 solar masses, they are representative of objects with a reasonable age span. In this paper, we present an estimate of the time variation of the O/H radial gradient in a sample containing over 200 nebulae with accurate abundances. Our results are consistent with a flattening of the O/H gradient roughly from -0.11 dex/kpc to -0.06 dex/kpc during the last 9 Gyr, or from -0.08 dex/kpc to -0.06 dex/kpc during the last 5 Gyr.Comment: 9 pages, 7 encapsulated postscript figures, LaTeX, uses Astronomy and Astrophysics macro aa.cls, graphicx package, to be published in Astronomy and Astrophysics (2002), Also available at: http://www.astro.iag.usp.br/~macie

Investigating potential planetary nebula/cluster pairs

Fundamental parameters characterizing the end-state of intermediate-mass stars may be constrained by discovering planetary nebulae (PNe) in open clusters (OCs). Cluster membership may be exploited to establish the distance, luminosity, age, and physical size for PNe, and the intrinsic luminosity and mass of its central star. Four potential PN-OC associations were investigated, to assess the cluster membership for the PNe. Radial velocities were measured from intermediate-resolution optical spectra, complemented with previous estimates in the literature. When the radial velocity study supported the PN/OC association, we analyzed if other parameters (e.g., age, distance, reddening, central star brightness) were consistent with this conclusion. Our measurements imply that the PNe VBe3 and HeFa1 are not members of the OCs NGC5999 and NGC6067, respectively, and likely belong to the background bulge population. Conversely, consistent radial velocities indicate that NGC2452/NGC2453 could be associated, but our results are not conclusive and additional observations are warranted. Finally, we demonstrate that all the available information point to He2-86 being a young, highly internally obscured PN member of NGC4463. New near-infrared photometry acquired via the Vista Variables in the Via Lactea ESO public survey was used in tandem with existing UBV photometry to measure the distance, reddening, and age of NGC4463, finding d=1.55+-0.10 kpc, E(B-V)=0.41+-0.02, and tau=65+-10 Myr, respectively. The same values should be adopted for the PN if the proposed cluster membership will be confirmed.Comment: Accepted for publication in A&