How personality traits relate to the self‐esteem of Greek children and adolescents with dyslexia

The main aim of the current study is to find out whether personality traits have any influence on self‐ esteem of dyslexic adolescents. Personality traits were first identified by the use of the ‘Personality Questionnaire for Children and adolescents’ (Besevegis & Paulopoulos, 1998) while self‐esteem was measured by the ‘Culture‐free Self‐esteem Inventory’ (Battle, 1992). The participants consisted of 86 adolescents ‐boys and girls‐ aged 11 to 14 years old diagnosed with dyslexia. The results of the study indicated that two of the personality factors: conscientiousness (organization and achievement) and intelligence (receptivity to new experiences and self‐confidence) play a significant role in their self‐ esteem. As far as the other factors were concerned the results of the study showed that they didn’t play a significant role in self‐esteem. On a descriptive level it is clear that participants of high sociability and low withdrawal tend to have high self‐esteem

Anomalous reflection of visible light by all-dielectric gradient metasurfaces

Plane wave scattering by a planar metasurface composed of two periodically alternating rectangular dielectric rods is considered. A rigorous integral equation methodology is employed for the analysis and the accurate determination of the reflected and transmitted fields. Systematic optimizations with respect to the configuration’s parameters are performed, which reveal that it is possible to obtain significantly enhanced anomalous reflection (with simultaneously suppressed ordinary reflection predicted by Snell’s law) with power varying from 92% to almost 100% of the input one, depending on the color of the incident light. It is shown that these reflection properties are supported by metasurfaces easily realizable with specific low-loss dielectric materials. In this way, several all-dielectric optimal designs are reported that can be used in numerous applications demanding anomalous reflection in the visible rang

Mitigating Snell’s-Law Reflection and Transmission with Metasurfaces of Ordinary Dielectrics

Obtaining anomalous reflection and transmission (namely propagation along directions different from those predicted by Snell’s law) is investigated for plane waves impinging on a planar periodic metasurface composed of two dielectric layers. The associated boundary-value problem is treated by a rigorous entire-domain integral equation methodology. Optimizations with respect to the con- figuration’s parameters are performed which reveal that it is possible to obtain significantly enhanced anomalous transmission and reflection depending on the color of the incident light. The optimal parameter values correspond to metasurfaces which can be easily realizable by low-loss dielectric materials

Higher-order effects and ultra-short solitons in left-handed metamaterials

Starting from Maxwell's equations, we use the reductive perturbation method to derive a second-order and a third-order nonlinear Schroedinger equation, describing ultra-short solitons in nonlinear left-handed metamaterials. We find necessary conditions and derive exact bright and dark soliton solutions of these equations for the electric and magnetic field envelopes.Comment: 4 pages, 2 figures, Phys. Rev. E in pres

Giant enhancement of the controllable in-plane anisotropy of biased isotropic noncentrosymmetric materials with epsilon-negative multilayers

Giant in-plane anisotropy can be exhibited by a finitely thick periodic multilayer comprising bilayers of an isotropic noncentrosymmetric material and a non-dissipative isotropic medium of negative permittivity, when a dc electric field is applied in the thickness direction. Compared to a homogeneous layer of the noncentrosymmetric material with the same thickness as the periodic multilayer, the latter exhibits an effective in-plane anisotropy that can be three orders larger in magnitude. This enhancement gets more substantial at higher frequencies and is electrically controllable. The incorporation of dissipation reduces the enhancement of the effective in-plane anisotropy, which nevertheless remains significant. We expect the finitely thick periodic multilayer to be useful as a polarization transformer or a modulator in the terahertz regime fully controllable via external dc bia

Analytical investigations of ground modifications assisting the detection of buried object

A ground-penetrating radar (GPR) antenna excites a perfectly electric conducting inclusion buried inside the ground. The scattering problem is solved semi-analytically via integral equation techniques. The permittivity and thickness of a superstrate deposited atop the ground are determined such that the detectability of the inclusion is significantly increased. Results from numerical simulations are presented exhibiting the effectiveness of the approach. Emphasis is given on the effects that the shape of the buried inclusion has on the scattered field