Cargado dinámico de plugins en Rust en ausencia de estabilidad en la Interfaz Binaria de Aplicación

La toma de decisiones de muchas empresas modernas como Wayfair se basa en la recolección y análisis de datos de sus sistemas. Para llevarlo a cabo de forma eficiente en una escala masiva, deben usarse herramientas de alto rendimiento como Tremor, escrito con Rust, programación asíncrona con hilos y SIMD.A medida que Tremor evoluciona, sus tiempos de compilación crecen y, consecuentemente, se deteriora la experiencia de desarrollo. Esto se puede aliviar implementando un sistema de plugins que divide su único binario en componentes más pequeños compilables independientemente.Existen múltiples tecnologías disponibles para su desarrollo: lenguajes interpretados, WebAssembly, eBPF, comunicación inter-proceso o cargado dinámico. Sin embargo, muchas de ellas deben descartarse por no cumplir los estándares de eficiencia de Tremor. Entre las alternativas restantes, se escoge cargado dinámico por ser la más usable y popular.El cargado dinámico es imposible con tipos y funciones declarados con Rust puro, ya que su Interfaz Binaria de Aplicación (ABI) no es estable. Es necesario convertir los tipos al ABI de C, que sí es estable, y viceversa. Para facilitar el proceso, se pueden aprovechar librerías existentes y herramientas del lenguaje como macros procedurales.Dado que el cargado dinámico en Rust es un ecosistema muy nuevo, se debe contribuir en código abierto a gran cantidad de dependencias de Tremor para implementar la funcionalidad necesaria para un sistema de plugins. La complejidad del proyecto incrementa significativamente respecto al plan original, por lo que, aunque funcional, la implementación no alcanza alguno de los objetivos iniciales, principalmente relacionados con el rendimiento. Sin embargo, sirve como una buena base para futuras versiones de Tremor que sí que lo incluyan en producción y continuará evolucionando con el programa.<br /

Nanostructured In3SbTe2 antennas enable switching from sharp dielectric to broad plasmonic resonances

Phase-change materials (PCMs) allow for non-volatile resonance tuning of nanophotonic components. Upon switching, they offer a large dielectric contrast between their amorphous and crystalline phases. The recently introduced “plasmonic PCM” In3SbTe2 (IST) additionally features in its crystalline phase a sign change of its permittivity over a broad infrared spectral range. While optical resonance switching in unpatterned IST thin films has been investigated before, nanostructured IST antennas have not been studied, yet. Here, we present numerical and experimental investigations of nanostructured IST rod and disk antennas. By crystallizing the IST with microsecond laser pulses, we switched individual antennas from narrow dielectric to broad plasmonic resonances. For the rod antennas, we demonstrated a resonance shift of up to 1.2 µm (twice the resonance width), allowing on/off switching of plasmonic resonances with a contrast ratio of 2.7. With the disk antennas, we realized an increase of the resonance width by more than 800% from 0.24 µm to 1.98 µm while keeping the resonance wavelength constant. Further, we demonstrated intermediate switching states by tuning the crystallization depth within the resonators. Our work empowers future design concepts for nanophotonic applications like active spectral filters, tunable absorbers, and switchable flat optics

All‐Dielectric Programmable Huygens' Metasurfaces

Low‐loss nanostructured dielectric metasurfaces have emerged as a breakthrough platform for ultrathin optics and cutting‐edge photonic applications, including beam shaping, focusing, and holography. However, the static nature of their constituent materials has traditionally limited them to fixed functionalities. Tunable all‐dielectric infrared Huygens' metasurfaces consisting of multi‐layer Ge disk meta‐units with strategically incorporated non‐volatile phase change material Ge3Sb2Te6 are introduced. Switching the phase‐change material between its amorphous and crystalline structural state enables nearly full dynamic light phase control with high transmittance in the mid‐IR spectrum. The metasurface is realized experimentally, showing post‐fabrication tuning of the light phase within a range of 81% of the full 2π phase shift. Additionally, the versatility of the tunable Huygen's metasurfaces is demonstrated by optically programming the spatial light phase distribution of the metasurface with single meta‐unit precision and retrieving high‐resolution phase‐encoded images using hyperspectral measurements. The programmable metasurface concept overcomes the static limitations of previous dielectric metasurfaces, paving the way for “universal” metasurfaces and highly efficient, ultracompact active optical elements like tunable lenses, dynamic holograms, and spatial light modulators

App-based mindfulness training supported eudaimonic wellbeing during the COVID19 pandemic

A randomized-controlled-trial study (N = 219) tested two pre-registered hypotheses that mobile-phone app-based mindfulness training improves wellbeing and increases self-transcendent emotions: gratitude, self-compassion, and awe. Latent change score modeling with a robust maximum likelihood estimator was used to test how those changes are associated in the training versus the waiting-list group. The training increased wellbeing and all self-transcendent emotions regardless of interindividual variance in the changes across time. Changes in all self-transcendent emotions were positively associated with changes in wellbeing. The strength of those associations was comparable in the waiting-list group and the training group. More studies are needed to test whether the effects of mindfulness practice on wellbeing are driven by increases in self-transcendent emotions. The study was conducted over 6 weeks during the COVID19 pandemic. The results indicate that the mindfulness training can be an easily accessible effective intervention supporting eudaimonic wellbeing in face of adversity