Curvature(s) of a light wavefront in a weak gravitational field

The geometry of a light wavefront evolving from a flat wavefront under the action of weak gravity field in the 3-space associated to a post-Newtonian relativistic spacetime, is studied numerically by means of the ray tracing method.Comment: 3 pages, 1 fig, Talk given by JFPS at the 12th Marcel Grossmann conference (Paris, July, 2009), submitted to the Proceeding

Geometry of an accelerated rotating disk

We analyze the geometry of a rotating disk with a tangential acceleration in the framework of the Special Theory of Relativity, using the kinematic linear differential system that verifies the relative position vector of time-like curves in a Fermi reference. A numerical integration of these equations for a generic initial value problem is made up and the results are compared with those obtained in other works.Comment: 10 pages, LaTeX, 2 eps figs; typos corrected, added reference, minor changes; submitte

Mass Selection for Adaptation in Antigua Maize (Zea mays L.) Composite

Tropical maize (Zea mays L.) germplasm has had limited use in temperate areas because of photoperiod sensitivity. Antigua germplasm from the island Antigua was introduced co Iowa because of its resistance to important pests of maize and its heterosis exposed m crosses with ocher tropical varieties. Mass selection procedures were used to adapt the Antigua Composite germplasm co Iowa conditions. After. Six cycles of mass selection for earlier silk emergence, the selected Antigua Composite flowered 17 days earlier than the original composite. Grain yield and ocher agronomic traits of the adapted scram of Antigua were similar co chose of adapted varieties

Systematic procedure for the efficient design of folded waveguide comb-line filters

[EN] A systematic procedure for the efficient design of folded waveguide comb-line filters is presented. The proposed strategy is based on dividing the design process in more simple stages, in order to reduce the number of variables to be optimized in each step of the design process. The electrical response of an equivalent circuit model of the waveguide component considered in each step is used as a target response. Moreover, a method for obtaining an initial value for some key dimensions of the filter is also addressed. Finally, an S-band 6-pole folded comb-line filter has been successfully designed following the proposed design strategy.San-Blas, AA.; Pérez-Guijarro, J.; Boria Esbert, VE.; Guglielmi, M. (2019). Systematic procedure for the efficient design of folded waveguide comb-line filters. IEEE. 1-4. https://doi.org/10.1109/NEMO.2019.8853707S1

Seed treatments for improved germination of caper (Capparis spinosa)

[EN] This study analyses the effects of seven treatments for removing hardseededness and four for breaking physiological dormancy in caper seeds. Seeds were germinated in a growth chamber and the maximum germination percentage, the time to reach 50% of final germination and the mean relative cumulative rate were calculated. The logistic function was suitable for analysing caper seed germination. Acid scarification followed by the addition of a GA(3) solution to the germination substrate was the best, efficient and cost effective method for ensuring satisfactory seed germination. Acid scarification can be substituted by mechanical scarification with ultrasound. hot water scarification or soaking, but these procedures require longer germination periods to reach satisfactory germination levels. The soaking method proved useful enough to remove hardseededness and it is also the most simple among the assayed treatments.Pascual España, B.; San Bautista Primo, A.; Imbernon, A.; López Galarza, SV.; Alagarda Pardo, J.; Maroto Borrego, JV. (2004). Seed treatments for improved germination of caper (Capparis spinosa). Seed Science and Technology. 32(2):637-642. doi:10.15258/sst.2004.32.2.33S63764232