Universidad Pública de Navarra

About: Universidad Pública de Navarra is a education organization based out in Pamplona, Spain. It is known for research contribution in the topics: Population & Optical fiber. The organization has 3500 authors who have published 8166 publications receiving 177239 citations.

Equivalent-circuit models for split-ring resonators and complementary split-ring resonators coupled to planar transmission lines

Abstract: In this paper, a new approach for the development of planar metamaterial structures is developed. For this purpose, split-ring resonators (SRRs) and complementary split-ring resonators (CSRRs) coupled to planar transmission lines are investigated. The electromagnetic behavior of these elements, as well as their coupling to the host transmission line, are studied, and analytical equivalent-circuit models are proposed for the isolated and coupled SRRs/CSRRs. From these models, the stopband/passband characteristics of the analyzed SRR/CSRR loaded transmission lines are derived. It is shown that, in the long wavelength limit, these stopbands/passbands can be interpreted as due to the presence of negative/positive values for the effective /spl epsiv/ and /spl mu/ of the line. The proposed analysis is of interest in the design of compact microwave devices based on the metamaterial concept.

The paleozoic origin of enzymatic lignin decomposition reconstructed from 31 fungal genomes

Abstract: Wood is a major pool of organic carbon that is highly resistant to decay, owing largely to the presence of lignin. The only organisms capable of substantial lignin decay are white rot fungi in the Agaricomycetes, which also contains non-lignin-degrading brown rot and ectomycorrhizal species. Comparative analyses of 31 fungal genomes (12 generated for this study) suggest that lignin-degrading peroxidases expanded in the lineage leading to the ancestor of the Agaricomycetes, which is reconstructed as a white rot species, and then contracted in parallel lineages leading to brown rot and mycorrhizal species. Molecular clock analyses suggest that the origin of lignin degradation might have coincided with the sharp decrease in the rate of organic carbon burial around the end of the Carboniferous period.

Socioemotional Wealth and Corporate Responses to Institutional Pressures: Do Family-Controlled Firms Pollute Less?:

Abstract: This paper compares the environmental performance of family and nonfamily public corporations between 1998 and 2002, using a sample of 194 U.S. firms required to report their emissions. We found that family-controlled public firms protect their socioemotional wealth by having a better environmental performance than their nonfamily counterparts, particularly at the local level, and that for the nonfamily firms, stock ownership by the chief executive officer (CEO) has a negative environmental impact. We also found that the positive effect of family ownership on environmental performance persists independently of whether the CEO is a family member or serves both as CEO and board chair.

Babinet principle applied to the design of metasurfaces and metamaterials.

Abstract: The electromagnetic theory of diffraction and the Babinet principle are applied to the design of artificial metasurfaces and metamaterials. A new particle, the complementary split rings resonator, is proposed for the design of metasurfaces with high frequency selectivity and planar metamaterials with a negative dielectric permittivity. Applications in the fields of frequency selective surfaces and polarizers, as well as in microwave antennas and filter design, can be envisaged. The tunability of all these devices by an applied dc voltage is also achievable if these particles are etched on the appropriate substrate.