Analytical theory of wave propagation through stacked fishnet metamaterials

This work analyzes the electromagnetic wave propagation through periodically stacked fishnets from zero frequency to the first Wood's anomaly. It is shown that, apart from Fabry-Perot resonances, these structures support two transmission bands that can be backward under the appropriate conditions. The first band starts at Wood's anomaly and is closely related to the well-known phenomena of extraordinary transmission through a single fishnet. The second band is related to the resonances of the fishnet holes. In both cases, the in-plane periodicity of the fishnet cannot be made electrically small, which prevents any attempt of homogenization of the structure along the fishnet planes. However, along the normal direction, even with very small periodicity transmission is still possible. An homogenization procedure can then be applied along this direction, thus making that the structure can behave as a backward-wave transmission line for such transmission bands. Closed-form design formulas will be provided by the analytical formulation here presented. These formulas have been carefully validated by intensive numerical computations.Ministerio de Educación y Ciencia TEC2007-65376, TEC2007-68013-C02-01, CSD2008- 00066Junta de Andalucía TIC-253Czech Grant Agency 102/08/031

Analytical theory of extraordinary transmission through metallic diffraction screens perforated by small holes

In this letter, the problem of extraordinary (ET) transmission of electromagnetic waves through opaque screens perforated with subwave- length holes is addressed from an analytical point of view. Our purpose was to find a closed-form expression for the transmission coefficient in a simple case in order to explore and clarify, as much as possible, the physical background of the phenomenon. The solution of this canonical example, apart from matching quite well with numerical simulations given by commercial solvers, has provided new insight in extraordinary transmission as well as Wood's anomaly. Thus, our analysis has revealed that one of the key factors behind ET is the continuous increase of excess electric energy around the holes as the frequency approaches the onset of some of the higher-order modes associated with the periodicity of the screen. The same analysis also helps to clarify the role of surface modes -or spoof plasmons- in the onset of ET.Ministerio de Educación y Ciencia TEC2007-65376, TEC2007-68013-C02-01, CSD2008- 00066Junta de Andalucía TIC–25

Spatial angular filtering by FSSs made of chains of interconnected SRRs and CSRRs

Two frequency selective surfaces (FSSs) made of an infinite set of parallel 1-D chains of interconnected split ring resonators (I-SRRs) and interconnected complementary split ring resonators (I-CSRRs) are studied. The main result was that the central frequencies of the stopband and passband can be strongly tuned by controlling the angle of incidence.Colombian Administrative Departament of Science, Technology and Innovation 1101-521-29389Ministerio de Ciencia e Innovación CSD2008-00066, TEC2010-1694

Serendipitous discovery of RR Lyrae stars in the Leo V ultra-faint galaxy

During the analysis of RR Lyrae stars discovered in the High cadence Transient Survey (HiTS) taken with the Dark Energy Camera at the 4-m telescope at Cerro Tololo Inter-American Observatory, we found a group of three very distant, fundamental mode pulsator RR Lyrae (type ab). The location of these stars agrees with them belonging to the Leo V ultra-faint satellite galaxy, for which no variable stars have been reported to date. The heliocentric distance derived for Leo V based on these stars is 173 +/- 5 kpc. The pulsational properties (amplitudes and periods) of these stars locate them within the locus of the Oosterhoff II group, similar to most other ultra-faint galaxies with known RR Lyrae stars. This serendipitous discovery shows that distant RR Lyrae stars may be used to search for unknown faint stellar systems in the outskirts of the Milky Way.Comment: Accepted in ApJ Letter

Influence of source and micronization of soya bean meal on growth performance, nutrient digestibility and ileal mucosal morphology of Iberian piglets

The effects of inclusion in the diet of different sources of soya bean meal (SBM) on growth performance, total tract apparent digestibility (TTAD) and apparent ileal digestibility (AID) of major dietary components and mucosal ileum morphology were studied in Iberian pigs weaned at 30 days of age. From 30 to 51 days of age (phase I), there was a control diet based on regular soya bean meal (R-SBM; 44% CP) of Argentina (ARG) origin and five extra diets in which a high-protein soya bean meal (HP-SBM; 49% CP) of the USA or ARG origin, either ground (990 μm) or micronized (60 μm), or a soya protein concentrate (SPC; 65% CP) substituted the R-SBM. From 51 to 61 days of age (phase II), all pigs were fed a common commercial diet in mash form. The following pre-planned orthogonal contrasts were conducted: (1) R-SBM v. all the other diets, (2) SPC v. all the HP-SBM diets, (3) micronized HP-SBM v. ground HP-SBM, (4) HP-SBM of ARG origin v. HP-SBM of US origin and (5) interaction between source and the degree of grinding of the HP-SBM. Dietary treatment did not affect growth performance of the pigs at any age but from 30 to 51 days of age, post weaning diarrhoea (PWD) was higher (P<0.001) and the TTAD and AID of all nutrients were lower for pigs fed the R-SBM diet than for pigs fed the HP-SBM or the SPC diets. However, no differences between the HP-SBM and the SPC containing diets were detected for any trait. The TTAD of organic matter (P=0.07) and gross energy (GE) (P=0.05) tended to be higher for the micronized HP-SBM than for the ground HP-SBM and that of GE was higher (P<0.05) for US meal than for the ARG meal. Pigs fed R-SBM had lower villus height (P<0.01) than pigs fed HP-SBM or SPC but no differences in ileal mucosal morphology were detected between SPC and HP-SBM containing diets. It is concluded that feeding the HP-SBM or SPC-reduced PWD and improved nutrient digestibility and ileal morphology as compared with feeding the R-SBM, but had no effect on pig performance. The inclusion in the diet of added value soya products (micronized SBM or SPC) in substitution of the R-SBM increased the TTAD of all nutrients and reduced PWD but had no advantage in terms of growth performance over the use of ground HP-SBM

Cytomegalovirus-Associated Pancreatitis in Acquired Immunodeficiency Syndrome

A middle-aged woman suffering from CMV pancreatitis and HIV positive was treate

Multisubband ensemble Monte Carlo analysis of tunneling leakage mechanisms in ultrascaled FDSOI, DGSOI, and FinFET devices

Leakage phenomena are increasingly affecting the performance of nanoelectronic devices, and therefore, advanced device simulators need to include them in an appropriate way. This paper presents the modeling and implementation of direct source-to-drain tunneling (S/D tunneling), gate leakage mechanisms (GLMs) accounting for both direct tunneling and trap-assisted tunneling, and nonlocal band-to-band tunneling (BTBT) phenomena in a multissubband ensemble Monte Carlo (MS-EMC) simulator along with their simultaneous application for the study of ultrascaled fully depleted silicon-on-insulator, double-gate silicon-on-insulator, and FinFET devices. We find that S/D tunneling is the prevalent phenomena for the three devices, and it is increasingly relevant for short-channel lengths

Contribución al conocimiento de la flora de Andalucía: citas novedosas e interesantes de la provincia de Almería

Contribution to the knowledge about Andalusian flora: new and interesting cites of the Almería province.Palabras clave. Corología, Isla de Alborán, sureste ibérico, xenófitas.Key words. Corology, Alborán Island, South-Eastern Iberian Peninsula, xenophytes