Science with the World Space Observatory - Ultraviolet

The World Space Observatory-Ultraviolet (WSO-UV) will provide access to the UV range during the next decade. The instrumentation on board will allow to carry out high resolution imaging, high sensitivity imaging, high resolution (R~55000) spectroscopy and low resolution (R~2500) long slit spectroscopy. In this contribution, we briefly outline some of the key science issues that WSO-UV will address during its lifetime. Among them, of special interest are: the study of galaxy formation and the intergalactic medium; the astronomical engines; the Milky Way formation and evol ution, and the formation of the Solar System and the atmospheres of extrasolar p lanets.Comment: Just one text file (aigomezdecastro.tex). To be published in the proceeding of the conference: "New Quest in Stellar Astrophysics II: UV properties of evolved stellar populations" held in Puerto Vallarta - Mexico, in april 200

Comment on "Relativistic extension of shape-invariant potentials"

This comment directs attention to some fails of the Alhaidari approach to solve relativistic problems. It is shown that his gauge considerations are way off the mark and that the class of exactly solvable relativistic problems is not so enlarged as Alhaidari thinks it is

A novel programmable lysozyme-based lysis system in Pseudomonas putida for biopolymer production

Indexación: Scopus; Web of Science.Cell lysis is crucial for the microbial production of industrial fatty acids, proteins, biofuels, and biopolymers. In this work, we developed a novel programmable lysis system based on the heterologous expression of lysozyme. The inducible lytic system was tested in two Gram-negative bacterial strains, namely Escherichia coli and Pseudomonas putida KT2440. Before induction, the lytic system did not significantly arrest essential physiological parameters in the recombinant E. coli (ECPi) and P. putida (JBOi) strain such as specific growth rate and biomass yield under standard growth conditions. A different scenario was observed in the recombinant JBOi strain when subjected to PHA-producing conditions, where biomass production was reduced by 25% but the mcl-PHA content was maintained at about 30% of the cell dry weight. Importantly, the genetic construct worked well under PHA-producing conditions (nitrogen-limiting phase), where more than 95% of the cell population presented membrane disruption 16 h post induction, with 75% of the total synthesized biopolymer recovered at the end of the fermentation period. In conclusion, this new lysis system circumvents traditional, costly mechanical and enzymatic cell-disrupting procedures.https://www.nature.com/articles/s41598-017-04741-2.pd

Mirabolano 29C: obtenção de portaenxertos clonais por mergulhia aérea.

bitstream/item/30925/1/Circular-79.pd

Evidence of magnetic field decay in massive main-sequence stars

A significant fraction of massive main-sequence stars show strong, large-scale magnetic fields. The origin of these fields, their lifetimes, and their role in shaping the characteristics and evolution of massive stars are currently not well understood. We compile a catalogue of 389 massive main-sequence stars, 61 of which are magnetic, and derive their fundamental parameters and ages. The two samples contain stars brighter than magnitude 9 in the V band and range in mass between 5 and 100 Msun. We find that the fractional main-sequence age distribution of all considered stars follows what is expected for a magnitude limited sample, while that of magnetic stars shows a clear decrease towards the end of the main sequence. This dearth of old magnetic stars is independent of the choice of adopted stellar evolution tracks, and appears to become more prominent when considering only the most massive stars. We show that the decreasing trend in the distribution is significantly stronger than expected from magnetic flux conservation. We also find that binary rejuvenation and magnetic suppression of core convection are unlikely to be responsible for the observed lack of older magnetic massive stars, and conclude that its most probable cause is the decay of the magnetic field, over a time span longer than the stellar lifetime for the lowest considered masses, and shorter for the highest masses. We then investigate the spin-down ages of the slowly rotating magnetic massive stars and find them to exceed the stellar ages by far in many cases. The high fraction of very slowly rotating magnetic stars thus provides an independent argument for a decay of the magnetic fields.Comment: Accepted for publication on A&A; 9 pages, 8 figure

Yield, foliar concentration, and efficiency of extractant solutions with boron application in a Xanthic Ferralsol cultivated with banana in Central Amazon.

Boron is known to play important role in the structure of cell wall, membranes, and membrane-associated functions in plants. In soil, the hot water B extraction method has been extensively used, however, difficulties with this procedure result in low accuracy and precision of extraction of available boron (B) in soil. The objective of this study was to evaluate the Yield, foliar concentration, and efficiency of B extracting solutions and the effect of B fertilization on B uptake in banana leaves and fruits, subgroup Cavendish (AAA), cultivated in a Xanthic Ferralsol (dystrophic Yellow Latosol), in the Amazonas State, Brazil. The experimental design was a completely randomized split plot, comprising four boron rates (0, 4, 8, and 12 kg ha-1), and two harvest cycles (subtreatments), with four replicates. Available boron was determined with seven extractant solutions: Mehlich 1, Mehlich 3, hot water, HCl 0.05 mol L-1, HCl 0.1 mol L-1, HCl 5.0 mol L-1 and KCl 1.0 mol L-1. The application of B fertilizer increased the yield and concentration of B in leaves and fruits. Hot water and KCl 1.0 mol L-1 were the most efficient extracting solutions for the determination of available B in soil. The application of 3.4 kg B ha-1 in first cycle and 1.3 kg B ha-1 in second cycle guarantees an adequate nutritional status in banana plants.Paper 1054

B fields in OB stars (BOB): low-resolution FORS2 spectropolarimetry of the first sample of 50 massive stars

Within the context of the collaboration "B fields in OB stars (BOB)", we used the FORS2 low-resolution spectropolarimeter to search for a magnetic field in 50 massive stars, including two reference magnetic massive stars. Because of the many controversies of magnetic field detections obtained with the FORS instruments, we derived the magnetic field values with two completely independent reduction and analysis pipelines. We compare and discuss the results obtained from the two pipelines. We obtained a general good agreement, indicating that most of the discrepancies on magnetic field detections reported in the literature are caused by the interpretation of the significance of the results (i.e., 3-4 sigma detections considered as genuine, or not), instead of by significant differences in the derived magnetic field values. By combining our results with past FORS1 measurements of HD46328, we improve the estimate of the stellar rotation period, obtaining P = 2.17950+/-0.00009 days. For HD125823, our FORS2 measurements do not fit the available magnetic field model, based on magnetic field values obtained 30 years ago. We repeatedly detect a magnetic field for the O9.7V star HD54879, the HD164492C massive binary, and the He-rich star CPD -57 3509. We obtain a magnetic field detection rate of 6+/-4%, while by considering only the apparently slow rotators we derive a detection rate of 8+/-5%, both comparable with what was previously reported by other similar surveys. We are left with the intriguing result that, although the large majority of magnetic massive stars is rotating slowly, our detection rate is not a strong function of the stellar rotational velocity.Comment: 20 pages, 10 figures, 4 tables; accepted for publication on Astronomy & Astrophysic

Efficiency of boron application in an Oxisol cultivated with banana in the Central Amazon.

In the Amazon region, there is no information on the fertilization of banana plants with boron (B). Besides this, the extractant (hot water) currently used to test B concentrations has many limitations. The aim of this work was to study the effect of B on the fruit yield and quality of banana plants of the Cavendish (AAA) sub-group, grown in dystrophic Yellow Latosol (Oxisol or Xanthic Ferralsol), in the Amazonas State, Brazil. The experimental design was completely randomized split plot in a 4 × 2 factorial scheme, composed of four B rates (0, 4, 8 and 12 kg ha?1) and two harvest cycles (sub-treatments), with four replicates. The B availability in the soilwas determined by three extractants: Mehlich 3, hot water and KCl 1.0 mol L?1. The application of B influences the fruit yield, pulp/peel ratio, pulp resistance and B content in the leaves and fruits. The KCl 1.0 mol L?1 extractant was similar to the hot water in the evaluation of available B. To obtain maximum yield, it is necessary to apply 4.1 and 6.1 kg ha?1 of B in the first and second cycles, respectively