Tolerancia a heladas en variedades nativas y mejoradas de papa.

Peer Revie

Non-scattering Metasurface-bound Cavities for Field Localization, Enhancement, and Suppression

We propose and analyse metasurface-bound invisible (non-scattering) partially open cavities where the inside field distribution can be engineered. It is demonstrated both theoretically and experimentally that the cavities exhibit unidirectional invisibility at the operating frequency with enhanced or suppressed field at different positions inside the cavity volume. Several examples of applications of the designed cavities are proposed and analyzed, in particular, cloaking sensors and obstacles, enhancement of emission, and "invisible waveguides". The non-scattering mode excited in the proposed cavity is driven by the incident wave and resembles an ideal bound state in the continuum of electromagnetic frequency spectrum. In contrast to known bound states in the continuum, the mode can stay localized in the cavity infinitely long, provided that the incident wave illuminates the cavity

Neutrino oscillations in Kerr-Newman space-time

The mass neutrino oscillation in Kerr-Newman(K-N) space-time is studied in the plane $\theta=\theta_{0}$, and the general equations of oscillation phases are given. The effect of the rotation and electric charge on the phase is presented. Then, we consider three special cases: (1) The neutrinos travel along the geodesics with the angular momentum $L=aE$ in the equatorial plane. (2) The neutrinos travel along the geodesics with L=0 in the equatorial plane. (3) The neutrinos travel along the radial geodesics at the direction $\theta=0$. At last, we calculate the proper oscillation length in the K-N space time. The effect of the gravitational field on the oscillation length is embodied in the gravitational red shift factor. When the neutrino travels out of the gravitational field, the blue shift of the oscillation length takes place. We discussed the variation of the oscillation length influenced by the gravitational field strength, the rotation $a^{2}$ and charge $Q$.Comment: 20 pages, no figure

Constraints on Cosmological Models and Reconstructing the Acceleration History of the Universe with Gamma-Ray Burst Distance Indicators

Gamma-ray bursts (GRBs) have been regarded as standard candles at very high redshift for cosmology research. We have proposed a new method to calibrate GRB distance indicators with Type Ia supernova (SNe Ia) data in a completely cosmology-independent way to avoid the circularity problem that had limited the direct use of GRBs to probe cosmology [N. Liang, W. K. Xiao, Y. Liu, and S. N. Zhang, Astrophys. J. 685, 354 (2008).]. In this paper, a simple method is provided to combine GRB data into the joint observational data analysis to constrain cosmological models; in this method those SNe Ia data points used for calibrating the GRB data are not used to avoid any correlation between them. We find that the $\Lambda$CDM model is consistent with the joint data in the 1-$\sigma$ confidence region, using the GRB data at high redshift calibrated with the interpolating method, the Constitution set of SNe Ia, the cosmic microwave background radiation from Wilkinson Microwave Anisotropy Probe five year observation, the baryonic acoustic oscillation from the spectroscopic Sloan Digital Sky Survey Data Release 7 galaxy sample, the x-ray baryon mass fraction in clusters of galaxies, and the observational Hubble parameter versus redshift data. Comparing to the joint constraints with GRBs and without GRBs, we find that the contribution of GRBs to the joint cosmological constraints is a slight shift in the confidence regions of cosmological parameters to better enclose the $\Lambda$CDM model. Finally, we reconstruct the acceleration history of the Universe up to $z>6$ with the distance moduli of SNe Ia and GRBs and find some features that deviate from the $\Lambda$CDM model and seem to favor oscillatory cosmology models; however further investigations are needed to better understand the situation.Comment: 14 pages, 9 figures, 2 tables; v3: the revised version, fig. 6 and some discussions added, accepted for for publication in Phys. Rev. D; v4: the published version (Phys. Rev. D 81, 083518, 2010

Principios de manejo de control quimico del tizon tardio de la papa en Ecuador.

Es necesario establecer con claridad los principios del manejo químico de la enfermedad antes que recomendaciones explícitas del uso de fungicidas. Para establecer los principios de manejo, a su vez es necesario conocer la eficacia de control y los riesgos de resistencia de los patógenos a los fungicidas. Considerando que la base del control de la enfermedad es la rotación de fungicidas, posibles sinergias y antagonismos deben ser establecidos. Además, los niveles globales de toxicidad deben ser bajos y la eficacia alta; todos estos aspectos deben ser considerados para establecer los principios de manejo del control químico. Con estos antecedentes, estudios de eficacia, resistencia del patógeno a los fungicidas, rotación de fungicidas han permitido identificar los principios de manejo del tizón tardío, lo que permitirá el manejo sustentable de la enfermedad