2,164 research outputs found

    Concentrações de ácido indolbutírico no enraizamento de Cryptomeria japonica.

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    Cryptomeria japonica is a conifer of great load that detaches for the fast growth and good lumber potential. In spite of could being propagated by seeds, the vegetative propagation of Cryptomeria japonica is justified for the maintenance of the desirable characteristics of selected plus trees. In function of this and the lack of information about vegetative propagation out of Japan, this work had as objective to verify the effect of indolbutiric acid (IBA) and alcohol on rooting of cuttings of three adult clones of Cryptomeria japonica. The cuttings from three trees with nine years old, after prepared, received phytosanitary treatment for the clear, followed by the treatment with different concentrations of iba (T1 = 0 mg L-1; T2 = water + alcohol (1:1 v/v); T3 = 2,000 mg.L-1 IBA; T4 = 4,000 mg.L-1 IBA; T5 = 8,000 mg.L-1 IBA). The best results showed that the studied clones presents variation in clones in terms of the evaluated characteristics and has low level of rooting independent of the tested concentrations of IBA. the concentration with maximum technical efficiency is around 4,000 mg.L-1 IBA, with 22.9% of rooting for clone 2

    The strength of nuclear shell effects at N=126 in the r-process region

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    We have investigated nuclear shell effects across the magic number N=126 in the region of the r-process path. Microscopic calculations have been performed using the relativistic Hartree-Bogoliubov approach within the framework of the RMF theory for isotopic chains of rare-earth nuclei in the r-process region. The Lagrangian model NL-SV1 with the inclusion of the vector self-coupling of omega meson has been employed. The RMF results show that the shell effects at N=126 remain strong and exhibit only a slight reduction in the strength in going from the r-process path to the neutron drip line. This is in striking contrast to a systematic weakening of the shell effects at N=82 in the r-process region predicted earlier in the similar approach. In comparison the shell effects with microscopic-macroscopic mass formulae show a near constancy of shell gaps leading to strong shell effects in the region of r-process path to the drip line. A recent analysis of solar-system r-process abundances in a prompt supernova explosion model using various mass formulae including the recently introduced mass tables based upon HFB approach shows that whilst mass formulae with weak shell effects at N=126 give rise to a spread and an overproduction of nuclides near the third abundance peak at A~190, mass tables with droplet models showing stronger shell effects are able to reproduce the abundance features near the third peak appropriately. In comparison, several analyses of the second r-process peak at A~130 have required weakened shell effects at N=82. Our predictions in the RMF theory with NL-SV1, which exhibit weaker shell effects at N=82 and stronger one at N=126 in the r-process region, support the conjecture that a different nature of the shell effects at the magic numbers may be at play in r-process nucleosynthesis of heavy nuclei.Comment: 14 pages, 8 figures; submitted to Physical Review C. Part of this work was presented at Nuclear Physics in Astrophysics II, 20th International Nuclear Physics Divisional Conference of the European Physical Society, at Debrecen, Hungary, May 16-20, 200

    The additional-mode garden of RR Lyrae stars

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    Space-based photometric missions revealed a surprising abundance of millimagnitude-level additional modes in RR Lyrae stars. The modes that appear in the modulated fundamental-mode (RRab) stars can be ordered into four major categories. Here we present the distribution of these groups in the Petersen diagram, and discuss their characteristics and connections to additional modes observed in other RR Lyrae stars.Comment: 4 pages, 4 figures, proceedings of the Joint TASC2-KASC9-SPACEINN-HELAS8 Conference "Seismology of the Sun and the Distant Stars 2016", to be published in EPJ Wo

    Closed shells at drip-line nuclei

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    The shell structure of magic nuclei far from stability is discussed in terms of the self-consistent spherical Hartree-Fock-Bogoliubov theory. In particular, the sensitivity of the shell-gap sizes and the two-neutron separation energies to the choice of particle-hole and particle-particle components of the effective interaction is investigated.Comment: 19 pages, LaTeX, 8 uuencoded figures available upon reques

    Process Evaluation of the Los Angeles Unified School District Nutrition Network

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    IntroductionThis study evaluated the Los Angeles Unified School District Nutrition Network, a large multicomponent nutrition and physical activity program in an ethnically diverse school district, launched in 2000.MethodsWe calculated descriptive statistics and performed hierarchical logistic regression on school-level demographic and implementation data.ResultsThirty-six percent of eligible schools participated in 2001, and 79% of participating schools reapplied the following year. Elementary schools and schools that applied for grant money were more likely to re-apply. Produce sampling was the most frequently cited program highlight, and making purchases with program grant money was the most frequently cited challenge.ConclusionOur findings suggest that schools serving students of low socioeconomic status and diverse ethnicities can be recruited into a large program to promote healthy dietary choices and physical activity, especially elementary schools. Effectiveness and institutionalization of the program might be positively affected by fostering local ownership, allowing school personnel who apply for the grant to tailor the program to their individual schools

    Enraizamento de miniestacas de erva-mate sob diferentes ambientes.

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    Pouco se conhece a respeito da propagação vegetativa da erva-mate, principalmente em relação à miniestaquia e aos aspectos relacionados ao ambiente de enraizamento. O estudo objetivou avaliar o efeito do ambiente inicial de enraizamento sobre a sobrevivência, vigor da parte aérea e enraizamento de miniestacas da espécie. O delineamento experimental foi o inteiramente casualizado em arranjo fatorial (3x2), sendo três clones (A7, A21 e A35) e dois ambientes de enraizamento (casa-de-vegetação simples, sem controle de temperatura e umidade e casa-de-vegetação automatizada). A sobrevivência das miniestacas na saída das casas de enraizamento e na casa-de-sombra não foram influenciadas pelo ambiente testado, com variação de 51,8 % a 71,9 %. Os clones A7 e A21 não diferiram significativamente quanto ao enraizamento, com médias de 49,1 % e 46,4 %, respectivamente. Contudo, o clone A35 mostrou-se superior quando proveniente da casa-de-vegetação automatizada, com 62,5 % de enraizamento. A casa-de-vegetação automatizada favoreceu tanto o número de folhas quanto o número e comprimento das brotações emitidas. A miniestaquia de erva-mate pode ser considerada tecnicamente viável em ambos os ambientes de enraizamento testados, apresentando resultados semelhantes

    Turbine Electrified Energy Management (TEEM) For Enabling More Efficient Engine Designs

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    NASA is investing in Electrified Aircraft Propulsion (EAP) research as part of an effort to assist industry in meeting the future needs of a global aviation market. The integration of electric machines into traditional turbine-based propulsion provides opportunities to change system architectures effecting radical improvements in propulsive efficiency. However, less consideration has been afforded to the utilization of these electrical machines to improve the thermal efficiency and performance of the gas turbine engine. Noting this deficit, a novel operability concept is proposed and is referred to as Turbine Electrified Energy Management (TEEM). The concept is a transient control technology that supplements the main fuel control for the suppression of the natural off-design dynamics associated with changes in engine operating state. Here the electric machines, used as engine actuators during the transient, add or extract torque from the engine shafts to maintain the speed-flow characteristics of steady-state design operation. This greatly reduces the need to maintain transient stall margin stack in the compressors, among other potential benefits. This paper demonstrates the feasibility of the concept in dynamic simulation using a Numerical Propulsion System Simulation (NPSS) engine model of a NASA hybrid electric propulsion concept known as the Parallel Hybrid Electric Turbofan (hFan)
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