Metasurfaces for photon sorting and selective absorption

Metamaterials are a recent discovery gaining much interest due to their promising applications to multiple devices in sensing, imaging, photovoltaics, nonlinear optics, heat conversion, sorters, and multitudes of other devices. These metamaterials are made of subunits called meta-atoms which take a role similar to that of atoms in bulk crystals. However, unlike their atom counterparts, these meta-atoms are macroscopic and can be engineered to respond to a driving field in a desired way. Metasurfaces, the 2-dimensional analog of metamaterials, have been shown to possess the ability to control light in novel ways. In this work, we investigate a particular type of metasurface namely a cavity array metasurface which consists of a metal film with an array of apertures which form the meta-atoms. We will discuss methods for using such metasurfaces to develop innovative forms of photon sorting and frequency selective absorption. The metasurface devices presented illustrate how, by designing the cavity meta-atoms, various desired global properties can be achieved. Among the devices we will demonstrate are a novel polarization sensing pixel implementing a 1-dimensional polarization sorting metasurface, a Stokes parameter sensor device implementing a novel 2-dimensional cavity array metasurface, a 2-dimensional perfect absorbing metasurface with subwavelength photon sorting in the microwave, a 2-dimensional transmitting metasurface with subwavelength photon sorting in the near-IR, and an actively tunable frequency selective perfect absorber using two 2-dimensional metasurface

The growing racial pay gap is linked to rising income inequality and continued occupational segregation and discrimination.

Despite the civil rights movement of the 1960s and affirmative action policies, major pay gaps between whites and blacks persist. While the racial pay gap closed during the latter half of the 20th century, this trend reversed around 2000, and the gap has been growing ever since. In new research, Hadas Mandel and Moshe Semyonov examine a number of potential explanations for this reversal. They argue that the rising income inequality, along with continued occupational segregation and market discrimination, contributed to the enlargement of pay gaps between blacks and whites

AERO: Audio Super Resolution in the Spectral Domain

We present AERO, a audio super-resolution model that processes speech and music signals in the spectral domain. AERO is based on an encoder-decoder architecture with U-Net like skip connections. We optimize the model using both time and frequency domain loss functions. Specifically, we consider a set of reconstruction losses together with perceptual ones in the form of adversarial and feature discriminator loss functions. To better handle phase information the proposed method operates over the complex-valued spectrogram using two separate channels. Unlike prior work which mainly considers low and high frequency concatenation for audio super-resolution, the proposed method directly predicts the full frequency range. We demonstrate high performance across a wide range of sample rates considering both speech and music. AERO outperforms the evaluated baselines considering Log-Spectral Distance, ViSQOL, and the subjective MUSHRA test. Audio samples and code are available at https://pages.cs.huji.ac.il/adiyoss-lab/aer

Gain and Loss of Floral Scent Production through Changes in Structural Genes during Pollinator-Mediated Speciation

Summary The interactions of plants with their pollinators are thought to be a driving force in the evolution of angiosperms. Adaptation to a new pollinator involves coordinated changes in multiple floral traits controlled by multiple genes. Surprisingly, such complex genetic shifts have happened numerous times during evolution. Here we report on the genetic basis of the changes in one such trait, floral scent emission, in the genus Petunia (Solanaceae). The increase in the quantity and complexity of the volatiles during the shift from bee to hawkmoth pollination was due to de novo expression of the genes encoding benzoic acid/salicylic acid carboxyl methyltransferase (BSMT) and benzoyl-CoA:benzylalcohol/2-phenylethanol benzoyltransferase (BPBT) together with moderately increased transcript levels for most enzymes of the phenylpropanoid/benzenoid pathway. Loss of cinnamate-CoA ligase (CNL) function as well as a reduction in the expression of the {MYB} transcription factor {ODO1} explain the loss of scent during the transition from moth to hummingbird pollination. The {CNL} gene in the hummingbird-adapted species is inactive due to a stop codon, but also appears to have undergone further degradation over time. Therefore, we propose that loss of scent happened relatively early in the transition toward hummingbird pollination, and probably preceded the loss of UV-absorbing flavonols. The discovery that {CNL} is also involved in the loss of scent during the transition from outcrossing to selfing in Capsella (Brassicaceae) (see the accompanying paper) raises interesting questions about the possible causes of deep evolutionary conservation of the targets of evolutionary change

Effective Prevention of Microbial Biofilm Formation on Medical Devices by Low-Energy Surface Acoustic Waves

Low-energy surface acoustic waves generated from electrically activated piezo elements are shown to effectively prevent microbial biofilm formation on indwelling medical devices. The development of biofilms by four different bacteria and Candida species is prevented when such elastic waves with amplitudes in the nanometer range are applied. Acoustic-wave-activated Foley catheters have all their surfaces vibrating with longitudinal and transversal dispersion vectors homogeneously surrounding the catheter surfaces. The acoustic waves at the surface are repulsive to bacteria and interfere with the docking and attachment of planktonic microorganisms to solid surfaces that constitute the initial phases of microbial biofilm development. FimH-mediated adhesion of uropathogenic Escherichia coli to guinea pig erythrocytes was prevented at power densities below thresholds that activate bacterial force sensor mechanisms. Elevated power densities dramatically enhanced red blood cell aggregation. We inserted Foley urinary catheters attached with elastic-wave-generating actuators into the urinary tracts of male rabbits. The treatment with the elastic acoustic waves maintained urine sterility for up to 9 days compared to 2 days in control catheterized animals. Scanning electron microscopy and bioburden analyses revealed diminished biofilm development on these catheters. The ability to prevent biofilm formation on indwelling devices and catheters can benefit the implanted medical device industry

Spatial visual function in anomalous trichromats: Is less more?

Color deficiency is a common inherited disorder affecting 8% of Caucasian males with anomalous trichromacy (AT); it is the most common type of inherited color vision deficiency. Anomalous trichromacy is caused by alteration of one of the three cone-opsins' spectral sensitivity; it is usually considered to impose marked limitations for daily life as well as for choice of occupation. Nevertheless, we show here that anomalous trichromat subjects have superior basic visual functions such as visual acuity (VA), contrast sensitivity (CS), and stereo acuity, compared with participants with normal color vision. Both contrast sensitivity and stereo acuity performance were correlated with the severity of color deficiency. We further show that subjects with anomalous trichromacy exhibit a better ability to detect objects camouflaged in natural gray scale figures. The advantages of color-deficient subjects in spatial vision performance could explain the relatively high prevalence of color-vision polymorphism in humans

The prevalence of welfare state policies and gender socioeconomic inequality A comparative analysis

'The present study examines the hypotheses that progressive welfare-state policies are likely to increase women's labor force participation, but at the same time to increase both occupational segregation and earning gaps between economically active men and women. Using data from 20 industrialized countries (obtained from the Luxembourg Income Study), we combine both individual-level and country-level variables into one data file. The country-level variables pertain to a series of family oriented policies enacted by the state, and to the size of the public welfare sector. The data are analyzed to estimate the net effects of welfare state policies on female labor force participation, occupational segregation, and gender earnings inequality across the 20 countries. The analysis lends firm support to the hypothesis that progressive welfare policies are associated with higher rates of female labor force participation and with higher rates of gender-based occupational segregation but only limited support to the hypothesis that welfare-policies are likely to decrease gender inequality in earnings. The direct and indirect effects of welfare-state policies on earnings inequality obtained from multilevel regression models are discussed and re-evaluated in light of sociological theory.' (author's abstract)Die Studie prueft die Hypothese, dass progressive Wohlfahrtspolitik die Berufstaetigkeit von Frauen foerdert, gleichzeitig aber die berufliche Segregation und den Lohnunterschied zwischen berufstaetigen Frauen und Maennern ansteigen laesst. Es wurden Daten von 20 Industrielaendern aus der Luxemburger Einkommensstudie ausgewertet. Sowohl die individuelle als auch die Laenderebene werden zu einem neuen Datenbestand aufbereitet. Die Variablen der Laenderebenen sind wesentliche Bestandteile einer Reihe von familienorientierten sozialpolitischen Massnahmen. Die Daten wurden so aufbereitet, dass sie die Vernetzungseffekte von Wohlfahrtspolitik hinsichtlich des Anteils weiblicher Arbeitskraft, beruflicher Segregation und geschlechtsspezifischen Unterschieden im Verdienst erklaeren koennen. Die Analyse unterstuetzt die Hypothese, dass fortschrittliche Wohlfahrtspolitik verbunden ist mit hoeheren Raten von Frauenerwerbstaetigkeit und von geschlechtsspezifischer Segregation. Sie gibt aber nur begrenzt Auskunft ueber die Gueltigkeit der Hypothese, dass Wohlfahrtspolitik fuer die Verringerung von Lohnunterschieden geeignet sei. Die Ergebnisse der multivariaten Regressionsanalyse werden vor dem Hintergrund soziologischer Theorien diskutiert. (ICF)German title: Wohlfahrtsstaatliche Politik und geschlechtsspezifische soziooekonomische Ungleichheit: eine vergleichende AnalyseSIGLEAvailable from Luxembourg Income Study -LIS-, Luxembourg (LU) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

In Vitro and In Vivo Antimicrobial Activity of the Novel Peptide OMN6 against Multidrug-Resistant <i>Acinetobacter baumannii</i>

The rapid worldwide spread of antimicrobial resistance highlights the significant need for the development of innovative treatments to fight multidrug-resistant bacteria. This study describes the potent antimicrobial activity of the novel peptide OMN6 against a wide array of drug-resistant Acinetobacter baumannii clinical isolates. OMN6 prevented the growth of all tested isolates, regardless of any pre-existing resistance mechanisms. Moreover, in vitro serial-passaging studies demonstrated that no resistance developed against OMN6. Importantly, OMN6 was highly efficacious in treating animal models of lung and blood infections caused by multidrug-resistant A. baumannii. Taken together, these results point to OMN6 as a novel antimicrobial agent with the potential to treat life-threatening infections caused by multidrug-resistant A. baumannii avoiding resistance