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High-Performance Electrochemical and Photoelectrochemical Water Splitting at Neutral pH by Ir Nanocluster-Anchored CoFe-Layered Double Hydroxide Nanosheets
No full textHighly efficient electrocatalysts for the oxygen evolutionreaction(OER) in neutral electrolytes are indispensable for practical electrochemicaland photoelectrochemical water splitting technologies. However, thereis a lack of good, neutral OER electrocatalysts because of the poorstability when H+ accumulates during the OER and slow OERkinetics at neutral pH. Herein, we report Ir species nanocluster-anchored,Co/Fe-layered double hydroxide (LDH) nanostructures in which the crystallinenature of LDH-restrained corrosion associated with H+ andthe Ir species dramatically enhanced the OEC kinetics at neutral pH.The optimized OER electrocatalyst demonstrated a low overpotentialof 323 mV (at 10 mA cm(-2)) and a record low Tafelslope of 42.8 mV dec(-1). When it was integrated withan organic semiconductor-based photoanode, we obtained a photocurrentdensity of 15.2 mA cm(-2) at 1.23 V versus reversiblehydrogen in neutral electrolyte, which is the highest among all reportedphotoanodes to our knowledge
Remote Influences of ENSO and IOD on the Interannual Variability of the West Antarctic Sea Ice
No full textWest Antarctica exhibits a pronounced sea ice variability in interannual timescale, and 20%-30% of the total variance can be explained by the El Nino-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) during austral spring. The sea ice variation is primarily linked with anomalous atmospheric circulation in the Amundsen-Bellingshausen Sea (ABS) that modulates poleward atmospheric temperature advection and radiative forcing. With a co-varying relationship between ENSO and IOD, isolating their remote impacts on Antarctica has been limited in observations. An idealized experiment using the atmospheric model with a dry dynamical core suggests that the anticyclonic circulation anomaly in the ABS is primarily contributed by the ENSO in the Pacific Ocean, while the contribution of the IOD in the Indian Ocean is only one-third large. This study implies that atmospheric teleconnection through the southern Pacific Ocean is crucial for understanding the West Antarctic sea ice concentration variability.Plain Language Summary Antarctic sea ice, which affects the Earth's climate system, has gained considerable attention in recent years. Previous studies have shown that the El Nino-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) in the tropics affect the sea ice variation in West Antarctica through atmospheric teleconnections at interannual timescale. Unfortunately, due to the high positive correlation between these two climate modes, it is unclear how each phenomenon contributes to the West Antarctic sea ice variation. Therefore, this study investigates the underlying mechanisms related to the sea ice changes caused by ENSO and IOD during austral spring and quantifies the effect of each phenomenon on the West Antarctic sea ice through an idealized model experiment. It is found that the ENSO and the IOD account for 20%-30% of sea ice variance during austral spring, which is primarily contributed by the dynamic and thermodynamic mechanisms associated with atmospheric circulation in the Amundsen-Bellingshausen Sea (ABS). In addition, we confirm through the model experiments that the effect of ENSO in the Pacific Ocean on the atmospheric circulation patterns of ABS is about three times stronger than that of IOD in the Indian Ocean
Decoding Imagined Musical Pitch From Human Scalp Electroencephalograms
No full textBrain-computer interfaces (BCIs) can restore impaired cognitive functions in people with neurological disorders such as stroke. Musical ability is a cognitive function that is correlated with non-musical cognitive functions, and restoring it can enhance other cognitive functions. Pitch sense is the most relevant function to musical ability according to previous studies of amusia, and thus decoding pitch information is crucial for BCIs to be able to restore musical ability. This study evaluated the feasibility of decoding pitch imagery information directly from human electroencephalography (EEG). Twenty participants performed a random imagery task with seven musical pitches (C4-B4). We used two approaches to explore EEG features of pitch imagery: multiband spectral power at individual channels (IC) and differences between bilaterally symmetric channels (DC). The selected spectral power features revealed remarkable contrasts between left and right hemispheres, low- (<13 Hz) and high-frequency (> 13 Hz) bands, and frontal and parietal areas. We classified two EEG feature sets, IC and DC, into seven pitch classes using five types of classifiers. The best classification performance for seven pitches was obtained using IC and multiclass Support Vector Machine with an average accuracy of 35.68 +/- 7.47% (max. 50%) and an information transfer rate (ITR) of 0.37 +/- 0.22 bits/sec. When grouping the pitches to vary the number of classes (K = 2-6), the ITR was similar across K and feature sets, suggesting the efficiency of DC. This study demonstrates for the first time the feasibility of decoding imagined musical pitch directly from human EEG
Input optics systems of the KAGRA detector during O3GK
No full textKAGRA, the underground and cryogenic gravitational-wave detector, was operated for its solo observation from February 25 to March 10, 2020, and its first joint observation with the GEO 600 detector from April 7 to April 21, 2020 (O3GK). This study presents an overview of the input optics systems of the KAGRA detector, which consist of various optical systems, such as a laser source, its intensity and frequency stabilization systems, modulators, a Faraday isolator, mode-matching telescopes, and a high-power beam dump. These optics were successfully delivered to the KAGRA interferometer and operated stably during the observations. The laser frequency noise was observed to limit the detector sensitivity above a few kilohertz, whereas the laser intensity did not significantly limit the detector sensitivity
A multilevel model of expatriate staffing and subsidiary financial performance: An expanded fit perspective
No full textWe apply the fit theory to develop a multilevel framework of expatriate staffing effectiveness and argue that the advantages of utilizing expatriate managers are more salient in subsidiaries with market-seeking mandates in the host country. This effect is stronger if the parent firm places more emphasis on value appropriation than value creation. Such an impact is further moderated by the economic development of the host country, a country-level facilitating condition affecting the adaptability and value creation of the expatriates. The results based on a multilevel analysis of a panel dataset of foreign subsidiaries of South Korean global enterprises from 2006 to 2013 support our predictions
Automated Program Repair from Fuzzing Perspective
No full textIn this work, we present a novel approach that connects two closely-related topics: fuzzing and automated program repair (APR). The paper is divided into two parts. In the first part, we describe the similarities between fuzzing and APR both of which can be viewed as a search problem. In the second part, we introduce a new patch-scheduling algorithm called Casino, which is designed from a fuzzing perspective to enhance search efficiency. Our experiments demonstrate that Casino outperforms existing algorithms. We also promote open science by sharing SimAPR, a simulation tool that can be used to evaluate new patch-scheduling algorithms
Highly rapid detection of airborne coronaviruses through a water-encapsulating airborne virus concentrator and carbon nanotubes-based paper working electrodes
No full textVersatile Layered Hydroxide Precursors for Generic Synthesis of Cu-Based Materials
No full textThe ability to mix multiple elements in a structure is crucial for obtaining Cu-based nanostructures and microstructures with desirable physicochemical properties. Precursors containing multiple metal cations, such as layered double hydroxides, have been used for the synthesis of multielement materials. However, these precursors experience difficulty containing large cations, which limits the functionalities of the derived materials. Herein, the development of Cu-based hydroxy double salts (HDSs), versatile precursors that accommodate a broad range of metal cations with homogeneous distributions, is reported. Up to 25 different metal cations are mixed with Cu in an HDS single phase, individually and simultaneously. The HDSs further exhibit useful properties with respect to anion exchange, exfoliation, and phase transformation to metal oxides. During the metal oxide transformation process, the formed crystal structures are mainly dependent on the ionic radius of the secondary metal cations. To prove their utility as precursors, the metal oxides derived from the HDSs are tested and found that they exhibited high catalytic activities for CO oxidation. This study significantly expands the compositional and structural freedom of Cu-based multi-elemental materials
Circadian gating of light-induced arousal in Drosophila sleep
No full textCircadian rhythms and sleep homeostasis constitute the two-process model for daily sleep regulation. However, evidence for circadian control of sleep-wake cycles has been relatively short since clock-less animals often show sleep behaviors quantitatively comparable to wild-type. Here we examine Drosophila sleep behaviors under different light-dark regimes and demonstrate that circadian clocks gate light-induced arousal. Genetic excitation of tyrosine decarboxylase 2 (TDC2)-expressing neurons suppressed sleep more evidently at night, causing nocturnal activity. The arousal effects were likely mediated in part by glutamate transmission from the octopaminergic neurons and substantially masked by light. Application of T12 cycles (6-h light: 6-h dark) further showed that the light-sensitive effects of TDC2 neurons depended on the time of the day. In particular, light-sensing via visual input pathway led to strong sleep suppression at subjective night, and such an effect disappeared in clock-less mutants. Transgenic mapping revealed that light-induced arousal and free-running behavioral rhythms require distinct groups of circadian pacemaker neurons. These results provide convincing evidence that circadian control of sleep is mediated by the dedicated clock neurons for light-induced arousal