Indução de brotações em cepas de Cupressus lusitanica Mill. de diferentes idades.

Resumo

Concentrações de ácido indolbutírico no enraizamento de Cryptomeria japonica.

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

Substratos para enraizamento de estacas de Cryptomeria japonica Don.

Resumo

Miniestaquia de Eucalyptus benthamii x E. dunnii em substratos a base de casca de arroz carbonizada.

Objetivou-se avaliar a viabilidade técnica da utilização de diferentes granulometrias de casca de arroz carbonizada, pura ou em mistura com fibra de coco, substrato comercial a base de casca de pinus e vermiculita como componentes de substratos para produção de mudas de Eucalyptus benthamii x E. dunnii via miniestaquia. Para tanto, foram montados 14 substratos, nos quais as miniestacas foram enraizadas para produção das mudas (60 dias em casa de vegetação, 30 dias em casa de sombra e 30 dias em área de pleno sol). Avaliou-se: 1) a sobrevivência das miniestacas, número de raízes e comprimento da maior raiz na saída da casa de vegetação; 2) a sobrevivência na saída da casa de sombra e; 3) o percentual final de enraizamento após a permanência na área de pleno sol. Com base nos resultados obtidos, conclui-se que a casca de arroz carbonizada pode ser utilizada pura (granulometria de 0,5 a 1 mm e em sua forma íntegra) ou em composição com vermiculita (50%) como substrato para produção de mudas do híbrido em questão via miniestaquia

Heating in the Accreted Neutron Star Ocean: Implications for Superburst Ignition

We perform a self-consistent calculation of the thermal structure in the crust of a superbursting neutron star. In particular, we follow the nucleosynthetic evolution of an accreted fluid element from its deposition into the atmosphere down to a depth where the electron Fermi energy is 20 MeV. We include temperature-dependent continuum electron capture rates and realistic sources of heat loss by thermal neutrino emission from the crust and core. We show that, in contrast to previous calculations, electron captures to excited states and subsequent gamma-emission significantly reduce the local heat loss due to weak-interaction neutrinos. Depending on the initial composition these reactions release up to a factor of 10 times more heat at densities < 10^{11} g/cc than obtained previously. This heating reduces the ignition depth of superbursts. In particular, it reduces the discrepancy noted by Cumming et al. between the temperatures needed for unstable 12C ignition on timescales consistent with observations and the reduction in crust temperature from Cooper pair neutrino emission.Comment: 10 pages, 11 figures, the Astrophysical Journal, in press (scheduled for v. 662). Revised from v1 in response to referee's comment

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

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

Evaluation of design recommendations for the development of wheelchair rugby sports-wear

Currently, wheelchair rugby athletes face the challenges of playing the sport without specifically designed sports-wear kit. A few designs and recommendations have already been proposed by researchers but none have made it to market yet. The purpose of this study was to evaluate a set of design recommendations for the development of wheelchair rugby sports-wear. This was done so that the products to be created are developed in collaboration with their potential users, responding to their particular needs and requirements. The evaluation was done through an online survey, where the athletes were presented with a visual representation of the design recommendations. The results indicate that the people questioned agree with the majority of the proposed designs and would be happy to have these improvements made to their current sports-wear. The most criticised recommendations were for the gloves, as they are the most important part of the kit, so it is important that they are adequate and allow for a good performance

On the Origin of the Early Solar System Radioactivities. Problems with the AGB and Massive Star Scenarios

Recent improvements in stellar models for intermediate-mass and massive stars are recalled, together with their expectations for the synthesis of radioactive nuclei of lifetime $\tau \lesssim 25$ Myr, in order to re-examine the origins of now extinct radioactivities, which were alive in the solar nebula. The Galactic inheritance broadly explains most of them, especially if $r$-process nuclei are produced by neutron star merging according to recent models. Instead, $^{26}$Al, $^{41}$Ca, $^{135}$Cs and possibly $^{60}$Fe require nucleosynthesis events close to the solar formation. We outline the persisting difficulties to account for these nuclei by Intermediate Mass Stars (2 $\lesssim$ M/M$_\odot \lesssim 7 - 8$). Models of their final stages now predict the ubiquitous formation of a $^{13}$C reservoir as a neutron capture source; hence, even in presence of $^{26}$Al production from Deep Mixing or Hot Bottom Burning, the ratio $^{26}$Al/$^{107}$Pd remains incompatible with measured data, with a large excess in $^{107}$Pd. This is shown for two recent approaches to Deep Mixing. Even a late contamination by a Massive Star meets problems. In fact, inhomogeneous addition of Supernova debris predicts non-measured excesses on stable isotopes. Revisions invoking specific low-mass supernovae and/or the sequential contamination of the pre-solar molecular cloud might be affected by similar problems, although our conclusions here are weakened by our schematic approach to the addition of SN ejecta. The limited parameter space remaining to be explored for solving this puzzle is discussed.Comment: Accepted for publication on Ap

Relativistic mean field study of the properties of Z=117 nucleus and the decay chains of 293,294^{293,294}117 isotopes

We have calculated the binding energy, root-mean-square radius and quadrupole deformation parameter for the recently synthesized superheavy element Z=117, using the axially deformed relativistic mean field (RMF) model. The calculation is extended to various isotopes of Z=117 element, strarting from A=286 till A=310. We predict almost spherical structures in the ground state for almost all the isotopes. A shape transition appears at about A=292 from prolate to a oblate shape structures of Z=117 nucleus in our mean field approach. The most stable isotope (largest binding energy per nucleon) is found to be the $^{288}$117 nucleus. Also, the Q-value of $\alpha$-decay $Q_\alpha$ and the half-lives $T_{\alpha}$ are calculated for the $\alpha$-decay chains of $^{293}$117 and $^{294}$117, supporting the magic numbers at N=172 and/ or 184.Comment: 6 Pages and 8 Figure