Search

This research was supported by the grants PID2019-104619RB-C42 and PID2020-115183RB-C21 from the Spanish Ministry of Economy, Industry and Competitiveness and from the project INNJOBMAD-CM #H2019/HUM-5761, co-funded by the European Social Fund . All mistakes are the authors' own merits.

The COVID-19 pandemic was a challenge for the health systems of many countries. In the USA, COVID-19 accentuated political polarity. On the one hand, the defenders of more severe public health measures and, on the other, the advocates of individual rights and freedom above any other consideration. In this study, we analyse whether political partisanship and the political ideology of the different states of the USA have influenced the way COVID-19 was handled in the outbreak. Specifically, we analyse whether the ideology of each state affected the decrease in NO2 levels (used as a proxy for local economic activity and traffic) observed after the pandemic outbreak.

In this work, chemometric and spatial interpolation methods were used to characterize non-conventional pollutants in the atmosphere of the city of Santiago de Cali (Colombia), The contaminants were monitored using passive diffusion samplers during two (2) periods (January to February and March to April) in two consecutive years before the pandemic (2020). None of the cases exceeded the concentration limits established by the National Air Quality Standard. The Cluster analysis allowed evidencing the existence of groups, which correspond to low, medium and high influence sites of the pollutants. The Principal Components Analysis (PCA) led to gathered all the variables in two constituents: the first one (PC1) could be related as an indicator of pollutant mobile sources due to the similar contribution of pollutants, while the second one (PC2) as an indicator for punctual emissions of toluene, as it was the one that contributed the most. The performance of the spatial analysis drove to identify the downtown and north of the city as areas of high-influence of PC1, at the same time, a substantial decrease in its effects to the periphery, particularly towards the south. On the other hand, with the Inverse Distance Weighting (IDW) it was possible to observe the hot-spots of both PCs, particularly real estate construction areas and the downtown industrial sector of the city. Finally, it was found a cancer risk in downtown and north-eastern areas of the city, related to the exposure to benzene and ethylbenzene; observation that coincide in the area of incidence of PC1.

International audience; Perfect magnetic mirrors are important optical devices for the development of novel optical detectors, solar cells, and imaging devices. They have the property of only reversing the magnetic field of a light wave upon reflection, for instance, in functional optical metasurfaces. To design an optical magnetic mirror, high-refractive-index dielectric nanostructures that support strong magnetic dipole (MD) response in the optical wavelength range are used. However, the spectral overlap between the MD and electric dipole in dielectric resonators degrades the magnetic mirror reflection. Here, we propose and demonstrate a perfect optical magnetic mirror metasurface that totally reflects an incident wave without electric field phase change. In this perfect magnetic mirror, the electric dipole radiation is completely suppressed by the radiation of the anapole mode in the spectral range where the destructive interference between the electric dipole and toroidal dipole occurs. By fine-tuning the size parameters of the dielectric resonators, we show near-perfect MD scattering as a result of the spectral overlap between MD resonance and anapole mode. The optical magnetic mirror can be tuned from the visible to near-infrared range by scaling the sizes of the resonators. The MD scattering resonators promote the perfect magnetic mirror, a promising platform for designing photodetectors, biological sensors, and reflected waveplates.

The efficient manipulation of light-matter interactions in subwavelength all-dielectric nanostructures offers a unique opportunity for the design of novel low-loss visible- and telecom-range nanoantennas for light routing applications. Several studies have achieved longitudinal and transverse light scattering with a proper amplitude and phase balance among the multipole moments excited in dielectric nanoantennas. However, they only involve the interaction between electric dipole, magnetic dipole, and up to the electric quadrupole. Here, we extend and demonstrate a unidirectional transverse light scattering in a V-shaped silicon nanoantenna that involves the balance up to the magnetic quadrupole moment. Based on the long-wavelength approximation and exact multipole decomposition analysis, we find the interference conditions needed for near-unity unidirectional transverse light scattering along with near-zero scattering in the opposite direction. These interference conditions involve relative amplitude and phases of the electromagnetic dipoles and quadrupoles supported by the silicon nanoantenna. The conditions can be applied for the development of either polarization- or wavelength- dependent light routing on a V-shaped silicon and plasmonic nanoantennas.

We demonstrate a high-performance subwavelength scale plasmonic enhanced graphene/hexagonal boron nitride/graphene-based silicon electro-optic modulator, enabling low energy consumption for applications in communications, nonlinear photonics, and photonic neuromorphic networks.

Covid-19 pandemic was a challenge for the health systems of many countries. It altered people’s way of life and shocked the world economy. In the United States, political ideology has clashed with the fight against the pandemic. President Trump’s denial prevailed despite the warnings from the WHO and scientists who alerted of the seriousness of the situation. Despite this, some state governments did not remain passive in the absence of federal government measures, and passed laws restricting mobility (lockdowns). Consequently, the political polarity was accentuated. On the one hand, the defenders of more severe public health measures and, on the other, the advocates of individual rights and freedom above any other consideration. In this study, we analyze whether political partisanship and the political ideology has influenced the way Covid-19 was handled at the outbreak. Specifically, we analyze by using a Diff-in-Diff model, whether the ideology of each state, measure at three levels, affected the decrease in the NO2 levels observed after the pandemic outbreak in the US. We distinguish three alternative post-Covid periods and results show that the State ideology has a robust negative impact on the NO2 levels. There is an important difference between Democratic and Republican states, not just in the scope and following-up of the mobility and activity restrictions, but also in the speed they implemented them.

Hybrid integrated quantum photonic circuits possess the potential to scale up the number of quantum nodes with distributed quantum-information-processing units at affordable resources. One of the key requirements is to achieve high-efficiency and unidirectional coupling of single quantum emitters into the low loss dielectric photonic waveguide modes. Plasmonic waveguides have the capability to have high coupling efficiency due to enhanced light–matter interactions. However, they suffer from significant propagation losses. Here we design and numerically demonstrate an on-chip hybrid plasmonic–photonic integrated single-photon source that enhances the emission rate of a quantum emitter and possesses unidirectional emission to a waveguide with high coupling efficiency. Currently, the emission rate of the single emitter is enhanced by a factor of 20, and the coupling efficiency from the single emitter into the photonic circuit exceeds 70%. The integrated hybrid single-photon source could find applications in quantum-information technologies.

We present the design and the numerical modeling of electrically-tunable plasmonic metasurface absorber based on the Babinet’s principle in the mid-infrared spectrum. The plasmonic metasurface consist of an array of gold nanoantennas on a dielectric layer followed by gold substrate in a metal-insulator-metal (MIM) configuration. A graphene layer placed on top of the array enables electrical tuning of the antenna optical response. Finite-difference time-domain (FDTD) -based simulations were carried out using a commercially implemented FDTD Solutions to obtain the optical response of the metasurface. Based on the Babinet’s principle, we design and numerically modeled the complementary metasurface. We found that, even with the graphene layer, the complementary metasurfaces comply with the Babinet’s principle. These metasurfaces can found application as electrically-tunable sources in the mid-infrared range.

Transverse electric (TE)-pass polarizers integrated in silicon-on-insulator photonic circuits, based on hybrid plasmonic absorption, have been widely discussed as a key component for applications in information and communication technologies. Nevertheless, the complementary transverse magnetic (TM)-pass polarizer has not been developed due to the TM nature of plasmonic modes. Here, we experimentally demonstrate a nano-scale TM-pass polarizer based on TE-polarized plasmonic absorption using a periodic metal nanoparticle chain integrated on a silicon waveguide. Currently, the measured extinction ratio is 23 dB μm−1 and the insertion loss is 2.4 dB μm−1 at the central wavelength of 1.59 μm, in a device with a footprint of 630 nm (0.4λ). This polarization-selective absorption is analyzed using dispersion curves and transmission near-field scanning optical microscopy. The nanophotonic device completes an integrated polarizer based on plasmonic absorption and provides the necessary footprint for high density integration in photonic integrated circuits.

Hexagonal boron nitride (hBN) is one of the most suitable 2D materials for supporting graphene in electronic devices, and it plays a fundamental role in screening out the effect of charge impurities in graphene in contrast to inhomogeneous supports such as silicon dioxide (SiO2). Although many interesting surface science techniques such as scanning tunneling microscopy (STM) revealed dielectric screening by hBN and emergent physical phenomena were observed, STM is only appropriate for graphene electronics. In this paper, we demonstrate the dielectric screening by hBN in graphene integrated on a silicon photonic waveguide from the perspective of a near-field scanning optical microscopy (NSOM) and Raman spectroscopy. We found shifts in the Raman spectra and about three times lower slope decrease in the measured electric near-field amplitude for graphene on hBN relative to that for graphene on SiO2. Based on finite-difference time-domain simulations, we confirm lower electric field slope and scattering rate in graphene on hBN, which implies dielectric screening, in agreement with the NSOM signal. Graphene on hBN integrated on silicon photonics can pave the way for high-performance hybrid graphene photonics.

During the months of May, June, July and August 2019 the Red Band Difference algorithm was tested over Irish waters to assess its suitability for the Irish harmful algal bloom alert system. Over the 4 weeks of June an extensive localised surface phytoplankton bloom formed in the Celtic Sea, south of Ireland. Satellite imagery from the Sentinel-3a’s Ocean and Land Colour Instrument, processed using the Red Band Difference algorithm detected the bloom in surface shelf waters and helped monitor its movement. Daily satellite images indicated that the bloom appeared at the sea surface on the 2nd June 2019 and peaked in size and surface abundance in offshore shelf waters within 4 weeks, remnants remained at the surface into July. A particle tracking approach was used to replicate oceanic circulation patterns in the vicinity of the observed algal bloom and estimate its trajectory. The initial horizontal distribution of particles in the tracking model were based on a satellite imagery polygon of the bloom when it first appeared in surface waters. Good agreement was observed between satellite imagery of the bloom and the particle tracking model. In situ sampling efforts from a research cruise and the national inshore phytoplankton monitoring programme confirmed that Karenia mikimotoi was the causative organism of the bloom. This pilot study shows great potential to use the Red Band Difference algorithm in the existing Irish harmful algal bloom alert system. In addition, satellite ocean colour data combined with particle tracking model estimates can be a useful tool to monitor high biomass harmful algal bloom forming species, such as Karenia mikimotoi, in surface coastal waters around Ireland and elsewhere.

Chip-scale integrated optical devices are one of the most developed research subjects in last years. These devices serve as a bridge to overcome size mismatch between diffraction-limited bulk optics and nanoscale photonic devices. They have been employed to develop many on-chip applications, such as integrated light sources, polarizers, optical filters, and even biosensing devices. Among these integrated systems can be found the so-called hybrid photonic-plasmonic devices, structures that integrate plasmonic metamaterials on top of optical waveguides, leading to outstanding physical phenomena. In this contribution, we present a comprehensive study of the design of hybrid photonic-plasmonic systems consisting of periodic arrays of metallic nanowires integrated on top of dielectric waveguides. Based on numerical simulations, we explain the physics of these structures and analyze light coupling between plasmonic resonances in the nanowires and the photonic modes of the waveguides below them. With this chapter we pretend to attract the interest of research community in the development of integrated hybrid photonic-plasmonic devices, especially light interaction between guided photonic modes and plasmonic resonances in metallic nanowires.

Short and long-term exposure to air pollutants has been shown to be strongly associated with mortality and morbidity. This is a particular problem in big cities, largely due to traffic. In response, low emission zones (LEZ) are becoming more common in cities all over the world. London introduced its Toxicity Charge in 2017 and the more restrictive Ultra Low Emission Zone (ULEZ) in 2019. In this paper, we evaluate the effectiveness of these policies on NO2 levels. Our results show that NO2 levels significantly dropped in the roadside stations, especially after the implementation of the ULEZ. Similarly, at the background stations, the Toxicity Charge and the ULEZ had a similar, smaller effect. Furthermore, our results suggest that there was a positive spillover effect associated with both traffic policies, which was, however limited to the area within the North and South Circular Roads. In any case, while these policies have been useful to comply with the recommended limits on NO2 levels, alleviating Londoners’ health problems, they need to be enhanced since some stations still are above those limits.

The development of integrated photonic devices has led to important advancements in the field of light-matter interaction at the nanoscale. One of the main focal points is the coupling between single photon emitters and optical waveguides aiming to achieve efficient optical confinement and propagation. In this work, we focus on the characterization of a hybrid dielectric/plasmonic waveguide consisting of a gold triangular nanoantenna placed on top of a TiO2 waveguide. The strong directionality of the device is experimentally demonstrated by comparing the intensity scattered by the nanotriangle to the one scattered by a SNOM tip for different illumination geometries. The ability of the plasmonic antenna to generate powerful coupling between a single emitter and the waveguide will also be highlighted through numerical simulations.

Azaspiracids (AZA) are a group of lipophilic toxins, which are produced by a few species of the marine nanoplanktonic dinoflagellates Azadinium and Amphidoma (Amphidomataceae). A survey was conducted in 2018 to increase knowledge on the diversity and distribution of amphidomatacean species and their toxins in Irish and North Sea waters (North Atlantic). We here present a detailed morphological, phylogenetic, and toxinological characterization of 82 new strains representing the potential AZA producers Azadinium spinosum and Amphidoma languida. A total of ten new strains of Am. languida were obtained from the North Sea, and all conformed in terms of morphology and toxin profile (AZA-38 and-39) with previous records from the area. Within 72 strains assigned to Az. spinosum there were strains of two distinct ribotypes (A and B) which consistently differed in their toxin profile (dominated by AZA-1 and -2 in ribotype A, and by AZA-11 and -51 in ribotype B strains). Five strains conformed in morphology with Az. spinosum, but no AZA could be detected in these strains. Moreover, they revealed significant nucleotide differences compared to known Az. spinosum sequences and clustered apart from all other Az. spinosum strains within the phylogenetic tree, and therefore were provisionally designated as Az. cf. spinosum. These Az. cf. spinosum strains without detectable AZA were shown not to cause amplification in the species-specific qPCR assay developed to detect and quantify Az. spinosum. As shown here for the first time, AZA profiles differed between strains of Az. spinosum ribotype A in the presence/absence of AZA-1, AZA-2, and/or AZA-33, with the majority of strains having all three AZA congeners, and others having only AZA-1, AZA-1 and AZA-2, or AZA-1 and AZA-33. In contrast, no AZA profile variability was observed in ribotype B strains. Multiple AZA analyses of a period of up to 18 months showed that toxin profiles (including absence of AZA for Az. cf. spinosum strains) were consistent and stable over time. Total AZA cell quotas were highly variable both among and within strains, with quotas ranging from 0.1 to 63 fg AZA cell&minus, 1. Cell quota variability of single AZA compounds for Az. spinosum strains could be as high as 330-fold, but the underlying causes for the extraordinary large variability of AZA cell quota is poorly understood.

International audience; We present an experimental technique adapted to characterize individual metallic nanostructures in terms of differential reflectivity spectroscopy. We analyze gold patch nanoantennas holding different morphological properties. Our experimental methodology shows steady and reliable results consistent with classical analytical approximations and simulation methods. This technique allows us to identify absorption properties of metallic nanostructures commonly associated with surface plasmon resonances. By contrasting the light absorbed solely by the metallic antenna with respect to a surrounding reference medium, we found that some antennas show absorption of almost 50% of the incident light across the range of the visible spectrum. Plasmonic patch nanoantennas are promising systems in which the confinement of the electromagnetic field inside the dielectric gap strongly modifies the local density of states.

Okadaic acid (OA) group toxins may accumulate in shellfish and can result in diarrhetic shellfish poisoning when consumed by humans, and are therefore regulated. Purified toxins are required for the production of certified reference materials used to accurately quantitate toxin levels in shellfish and water samples, and for other research purposes. An improved procedure was developed for the isolation of dinophysistoxin-2 (DTX2) from shellfish (M. edulis), reducing the number of purification steps from eight to five, thereby increasing recoveries to ~68%, compared to ~40% in a previously reported method, and a purity of &gt, 95%. Cell densities and toxin production were monitored in cultures of Prorocentrum lima, that produced OA, DTX1, and their esters, over ~1.5 years with maximum cell densities of ~70,000 cells mL&minus, 1 observed. Toxin accumulation progressively increased over the study period, to ~0.7 and 2.1 mg L&minus, 1 of OA and DTX1 (including their esters), respectively, providing information on appropriate harvesting times. A procedure for the purification of OA and DTX1 from the harvested biomass was developed employing four purification steps, with recoveries of ~76% and purities of &gt, 95% being achieved. Purities were confirmed by LC-HRMS, LC-UV, and NMR spectroscopy. Additional stability observations led to a better understanding of the chemistry of these toxins.

Studies on wage discrimination assume that independent observers are able to distinguish a priori which workers are suffering from discrimination. However, this may not be a good assumption when anti-discrimination laws mean that severe penalties can be imposed on discriminatory employers or when unobserved heterogeneity is significant. We develop a wage discrimination model in which workers are not classified a priori. It can be thought of as a generalization of the standard empirical framework, whereas the Oaxaca–Blinder model can be thought of as an extreme case. We propose a finite mixture model to explicitly model unobserved heterogeneity in individual characteristics and estimate the probabilities of being a discriminated or a non-discriminated worker. We illustrate this proposal by estimating wage discrimination in Germany and the UK.

International audience; Plasmonic metalenses are optical elements that are able to shape the amplitude and the phase of light with a high spatial resolution, standing as promising elements for new low-weight imaging technologies. A desired characteristic for metalenses is to have an extended depth of focus (DOF) to bring a larger tolerance of placement of the image plane, reducing image blurring and increasing light directivity. Based on the Fresnel biprism and using the integral equation method, we numerically demonstrate light focusing with cylindrical plasmonic metalenses that are able to generate large DOF values of up to 150λ with transmission efficiencies around 50%. The easiness in the design of our plasmonic metalenses represents an advantage in terms of fabrication, opening new possibilities for the development of small-size lenses for light focusing and imaging applications.

Representatives of the marine dinophyte family Amphidomataceae produce lipophilic phycotoxins called azaspiracids (AZA) which may cause azaspiracid shellfish poisoning (AZP) in humans after consumption of contaminated seafood. Three of the four known toxigenic species are observed frequently in the eastern North Atlantic. In 2018, a research survey was performed to strengthen knowledge on the distribution and abundance of toxigenic Amphidomataceae and their respective toxins in Irish coastal waters and in the North Sea. Species-specific quantification of the three toxigenic species (Azadinium spinosum, Azadinium poporum and Amphidoma languida) was based on recently developed qPCR assays, whose performance was successfully validated and tested with specificity tests and spike experiments. The multi-method approach of on-board live microscopy, qPCR assays and chemical AZA-analysis revealed the presence of Amphidomataceae in the North Atlantic including the three targeted toxigenic species and their respective AZA analogues (AZA-1, -2, -33, -38, -39). Azadinium spinosum was detected at the majority of Irish stations with a peak density of 8.3 x 104 cells L-1 and AZA (AZA-1, -2, -33) abundances up to 1,274 pg L-1. Amphidoma languida was also present at most Irish stations but appeared in highest abundance in a bloom at a central North Sea station with a density of 1.2 x 105 cells L-1 and an AZA (AZA-38, -39) abundances of 618 pg L-1. Azadinium poporum was detected sporadically at the Irish south coast and North Sea and was rather low in abundance during this study. The results confirmed the wide distribution and frequent occurrence of the target species in the North Atlantic area and revealed, for the first time, bloom abundances of toxigenic Amphidomataceae in this area. This emphasizes the importance of future studies and monitoring of amphidomatacean species and their respective AZA analogues in the North Atlantic.

We present an experimental and numerical study of the optical properties of nanofabricated samples with layered dielectric structures. The samples, which contain periodic arrays of silicon disks over a flat layer of silicon dioxide on a silicon substrate, present diffraction and thin film interference effects. Well-defined circular fringes that modulate the intensity of the diffraction orders are observed in the far-field angular distribution of scattered light. We also find that although the angle of incidence modulates the intensity of the observed circular ring patterns, it has little or no effect on their angular position. The problem is modeled theoretically through numerical calculations based on a Rayleigh method.

An experimental and theoretical study of the scattering and diffraction properties of nanopatterned dielectric structures is presented. The samples consist of periodic arrays of silicon disks over a flat layer of silicon dioxide on a silicon substrate. The samples produce far-field scattering patterns that display a series of well-defined circular fringes that modulate the intensity of the diffraction orders. Simple models of the physical mechanisms that give rise to the observed phenomena are proposed. Measurements of the angular scattering distribution produced by the samples are presented and compared them with the results of numerical calculations.

The so-called on- and off-cells of the rostral ventromedial medulla (RVM) send their axons to the spinal dorsal horn. Activation of on-cells precedes and coincides with a facilitation, and activation of off-cells coincides with an inhibition, of withdrawal reflexes elicited by noxious agents. Considerable evidence supports the notion that on- and off-cells modulate nocifensive reflexes during opioid and non-opioid action and also during normal circumstances and during peripheral neuropathy and inflammation. Yet it is unclear whether on- and off-cells act upon sensory spinal circuits that might lead to ascending projections and the experience of pain. Here, in deeply anesthetized rats we recorded single unit discharges from pairs of one on-like or off-like cell in RVM and a nociceptive neuron in the spinal dorsal horn with input from a hind paw. Both ongoing activity and responses to a calibrated noxious stimulus applied to the paw were documented during basal conditions and during development of paw inflammation. Probably due to the strong barbiturate anesthesia, off-like cells were depressed and did not yield interpretable results. However, we showed for the first time that during the increase in neuronal activity that results from paw inflammation the activity of spinal nociceptive neurons reflects the activity of their partner on-like cells in a highly correlated manner. This implies a tight relationship between spinal sensory and RVM modulatory functions that may underlie inflammation-induced hyperreflexia and clinically relevant hyperalgesia.

Apparent increases in harmful algal blooms worldwide have fostered attempts at mitigating their impacts on the aquaculture industry. The dinoflagellate species Azadinium spinosum has been described as the de novo azaspiracid (AZA) toxin producer of AZA-1 and -2 and been implicated in shellfish poisoning incidents (AZP) around Europe, regularly affecting shellfish mariculture operations. Several species of Azadinium have been confirmed in Irish coastal waters, and routine monitoring has shown disparities between Azadinum spp. cell count estimates in the water column and AZA concentrations in shellfish. A survey of bays on the southwest and west coasts of Ireland, carried out in August 2016, investigated the late summer distribution of Azadinium spp. and AZAs. Molecular analysis of water column samples showed very low levels of Az. spinosum. However, AZAs were found in 44% of samples, including in Az. spinosum negative samples. PCR-DGGE analysis was carried out using Amphidomataceae family specific primers on a selection of Az. spinosum negative, but AZA positive, samples. Subsequently sequenced DNA amplicons showed a high level of similarity with other Azadinium species suggesting that the species-specific molecular assays, in current use for monitoring Azadinium spp., are not capturing the likely greater diversity of the genus in Irish waters.

Vavilov–Cherenkov radiation (CR), an electromagnetic radiation emission that occurs when a charged particle in a medium moves faster than the speed of light in the same medium, plays an important role in many areas of physics such as nuclear physics. Recently, CR has been investigated in photonics and plasmonics in the perspective of its application in velocity-dependent particle detection to enhance current particle detectors, thanks to the flexibility that offer integrated devices. In this contribution, the description of the excitation of eigenmodes in different integrated photonic and plasmonic structures by a uniformly moving charged particle is numerically presented. The CR that arise from such an interaction is described within the framework of an eigenmode analysis and validated with source and field propagation with the use of the finite-difference time-domain method. Integrated nanophotonics could provide a promising platform for the investigation of the interaction between electrons and photons on-chip.

El objeto del presente documento es exponer los lineamientos principales del estatuto juridico aplicable a las empresas comercializadoras de energia electrica, bajo la normativa contenida en el Anteproyecto de la Nueva Ley Electrica, elaborado por la Comision Nacional de Energia (CNE). Su exposicion se referira al concepto de comercializacion, la situacion de la comercializacion bajo la normativa actual y bajo las disposiciones del Anteproyecto, para terminar con las conclusiones del trabajo.

International audience; We investigated the augmentation in the light-output power of InGaN light-emitting diodes (LEDs) functionalized with ZnO nanorods (NRs) according to the emission wavelength of the LEDs and the volume fraction of the ZnO NRs. The ZnO NRs were fabricated on top of the ultraviolet, blue, and green InGaN LEDs using the hydrothermal method. The optical properties of the LEDs and ZnO NRs were examined by electroluminescence, photoluminescence, and Raman scattering at room temperature. The measurements of light-output power versus current and current as a function of voltage showed that there were considerably different enhancements in the light-output power of InGaN LEDs functionalized with ZnO NRs at different emission wavelengths of the LEDs, while no changes were observed in the electrical properties. Three-dimensional finite-difference time-domain simulations were conducted to support the experimental results. Both experimental and theoretical results indicated that the light-extraction efficiency of InGaN LEDs functionalized with ZnO NRs was significantly affected by the differences between the refractive indices of the GaN layers, indium–tin oxide layer, and ZnO NRs, which could be changed by the emission wavelength of the LEDs and volume fraction of the ZnO NRs.

We propose a definition of second-order discrimination that does not require the reference distribution to first-order dominate the comparison one, and allows rankings of discrimination patterns when both the reference and the comparison distributions differ. It involves comparing the probabilities that randomly selected individuals in the reference and comparison distributions belong to subgroups having the same cumulative mean income, yields orderings of distributions equivalent to those from generalized Lorenz dominance, and allows orderings of discrimination patterns, partial or complete, across pairs of distributions. We compare discrimination against U.S. seniors (inter-distributional inequality between seniors and non-seniors) by ethnicity.

Inequality, asymmetry, and the median-mean ratio are related but different concepts, although they have been frequently treated as equivalent in the literature. In this paper, we find important connections between these three concepts under particular conditions. We show that the Atkinson family and the generalized entropy class of inequality indices are simple functions of the medianmean ratio when a distribution is symmetrizable by a power transformation. In such a case, the coefficient of asymmetry can be interpreted as the aversion inequality parameter of a social planner, and a social evaluation function à la Kolm-Atkinson is shown to be equivalent to median income. A social evaluation function that depends only on mean income and inequality of opportunity is found as a by-product. In addition, the Hannah-Kay family of concentration indices (of which the Herfindahl-Hirschman is a special case) is also obtained as a function of the median-mean ratio. We illustrate these results empirically using the CPS dataset for the U.S. (1992—2007) and the EU-SILC dataset for the European Union (2005–2007).

International audience; We consider the design of magnetic mirrors that consist of a layer of two-dimensional high-refractive-index dielectric particles. The central idea is to search for conditions for which the electric field of the light backscattered by a single particle has a zero phase difference with respect to the incident field. Employing physical arguments, we conclude that this can occur when the electric dipolar contribution vanishes. Optimizing the form of the cross section, we find a situation in which the vanishing of the dipolar contribution coincides with an in-phase condition for the magnetic dipole and the electric quadrupole contributions. The resulting scattering pattern of the particle resembles that of an electric dipole, with the difference that the forward and backscattered electric fields have opposite signs. Based on these results, we design a metasurface reflector that behaves as a magnetic mirror at a specific wavelength within a wideband spectral response. Subsequently, we extend the results to the design of supported structures where a magnetic mirror condition at a single wavelength is similarly found.