4,133 research outputs found
A DIEBACK DISEASE OF MANGOS (MANGIFERA INDICA L.)
A DIEBACK DISEASE OF MANGOS (MANGIFERA INDICA L.
PHYTOPHTHORA DAMPING-OFF OF "BRUJAS" (BRYOPHYLLUM SPP.)
PHYTOPHTHORA DAMPING-OFF OF "BRUJAS" (BRYOPHYLLUM SPP.
Coherent Pion Production by Neutrinos
In this talk I review the main features of the coherent/diffractive pion
production by neutrinos on nuclei. The method is based on PCAC and relates the
reaction to elastic pion-nucleus scattering. Estimates for the
expected rates and distributions in neutrino reactions are presented with the
help of hadronic data. The absolute rates are significantly smaller than the
older estimates which brings theory in agreement with the neutral current
measurements and the bounds in charged current reactions.Comment: 5 pages, 7 figures, Proceedings of the Sixth International Workshop
on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt09), May 18-22,
Sitges, Barcelona, Spai
Critical formation of trapped surfaces in the collision of gravitational shock waves
We study the formation of marginally trapped surfaces in the head-on
collision of two shock waves both in anti-de Sitter and Minkowski space-time in
various dimensions as a function of the spread of the energy density in
transverse space. For D=4 and D=5 it is shown that there exists a critical
value of this spread above which no solution to the trapped surface equation is
found. In four dimensions the trapped surface at criticality has a finite size,
whereas in five the critical size vanishes. In both cases we find scaling
relations characterized by critical exponents. Finally, when D>5 there is
always a solution to the trapped surface equation for any transverse spread.Comment: 16 page
Einstein y la Geometria
This is a semipopular introduction to the Special and General Theory of
Relativity, with special emphasis on the geometrical aspects of both theories
and their physical implications.Comment: In Spanish, 20 pages. LaTeX, 8 figures. To appear in the Einstein
Special Issue of "Revista Espanola de Fisica
Algorithms for the Detection and Evasion of Obstacles on a Differential Mobile Platform for Interior Navigation
In this work, the algorithms necessary to execute displacements that allow indoor navigation for a differential mobile platform were designed, it was considered the programming of an Arduino Nano card connected to ultrasonic sensors that detect the distances of possible objects in the environment, and a Raspberry Pi3 card that is responsible for the activation and control of the platform’s engines. A high level of efficiency of the System was achieved by evading obstacles and protecting the robot structure as much as possible
Keywords: algorithms, interior navigation, differential mobile platform, Arduino, Raspberry Pi
SEARCHING for NEW YELLOW SYMBIOTIC STARS: POSITIVE IDENTIFICATION of StHα63
Yellow symbiotic stars are useful targets for probing whether mass transfer has happened in their binary systems. However, the number of known yellow symbiotic stars is very scarce. We report spectroscopic observations of five candidate yellow symbiotic stars that were selected by their positions in the 2MASS (J - H) versus (H - K) diagram and which were included in some emission-line catalogs. Among the five candidates, only StHα63 is identified as a new yellow symbiotic star because of its spectrum and its position in the [TiO]-[TiO] diagram, which indicates a K4-K6 spectral type. In addition, the derived electron density (∼10 cm) and several emission-line intensity ratios provide further support for that classification. The other four candidates are rejected as symbiotic stars because three of them actually do not show emission lines and the fourth one only Balmer emission lines. We also found that the WISE W3-W4 index clearly separates normal K-giants from yellow symbiotic stars and therefore can be used as an additional tool for selecting candidate yellow symbiotic stars.L.F.M. acknowledges partial support by grants AYA2011-30228-C03.01 and AYA2014-57369-C3-3-P of the Spanish MINECO, both co-funded by FEDER funds.Peer Reviewe
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