Biases in scholarly recommender systems: impact, prevalence, and mitigation

We create a simulated financial market and examine the effect of different levels of active and passive investment on fundamental market efficiency. In our simulated market, active, passive, and random investors interact with each other through issuing orders. Active and passive investors select their portfolio weights by optimizing Markowitz-based utility functions. We find that higher fractions of active investment within a market lead to an increased fundamental market efficiency. The marginal increase in fundamental market efficiency per additional active investor is lower in markets with higher levels of active investment. Furthermore, we find that a large fraction of passive investors within a market may facilitate technical price bubbles, resulting in market failure. By examining the effect of specific parameters on market outcomes, we find that that lower transaction costs, lower individual forecasting errors of active investors, and less restrictive portfolio constraints tend to increase fundamental market efficiency in the market

ScribFormer: Transformer Makes CNN Work Better for Scribble-based Medical Image Segmentation

Most recent scribble-supervised segmentation methods commonly adopt a CNN framework with an encoder-decoder architecture. Despite its multiple benefits, this framework generally can only capture small-range feature dependency for the convolutional layer with the local receptive field, which makes it difficult to learn global shape information from the limited information provided by scribble annotations. To address this issue, this paper proposes a new CNN-Transformer hybrid solution for scribble-supervised medical image segmentation called ScribFormer. The proposed ScribFormer model has a triple-branch structure, i.e., the hybrid of a CNN branch, a Transformer branch, and an attention-guided class activation map (ACAM) branch. Specifically, the CNN branch collaborates with the Transformer branch to fuse the local features learned from CNN with the global representations obtained from Transformer, which can effectively overcome limitations of existing scribble-supervised segmentation methods. Furthermore, the ACAM branch assists in unifying the shallow convolution features and the deep convolution features to improve model’s performance further. Extensive experiments on two public datasets and one private dataset show that our ScribFormer has superior performance over the state-of-the-art scribble-supervised segmentation methods, and achieves even better results than the fully-supervised segmentation methods. The code is released at https://github.com/HUANGLIZI/ScribFormer

HLG: A framework for computing graphs in Residue Number System and its application in Fully Homomorphic Encryption

Implementation of Fully Homomorphic Encryption (FHE) is challenging. Especially when considering hardware acceleration, the major performance bottleneck is data transfer. Here we propose an algebraic framework called Heterogenous Lattice Graph (HLG) to build and process computing graphs in Residue Number System (RNS), which is the basis of high performance implementation of mainstream FHE algorithms. There are three main design goals for HLG framework: • Design a dedicated IR (HLG IR) for RNS system, here splitting and combination of data placeholders has practical implications in an algebraic sense. Existing IRs cannot efficiently support these operations. • Lower the technical barriers for both crypto researchers and hardware engineers by decoupling front-end cryptographic algorithms from the back-end hardware platforms. The algorithms and solutions built on HLG framework can be written once and run everywhere. Researchers and engineers don’t need to understand each other. • Try to reduce the cost of data transfer between CPU and GPU/FPGA/dedicated hardware, by providing the intermediate representation (IR) of the computing graph for hardware compute engine, which allows task scheduling without help from CPU. We have implemented CKKS algorithm based on HLG framework, together with a compute engine for multiple CPU cores. Experiment shows that we can outperform SEAL v3 Library in several use cases in multi-threading scenarios

Photogenerated charge transfer via interfacial internal electric field for significantly improved photocatalysis in direct Z-scheme oxygen-doped carbon nitrogen/CoAl-layered double hydroxide heterojunction

Semiconductor heterojunctions, widely applied in photocatalytic solar-to-chemical energy conversion, are advantageous for spatially separating photogenerated charge across the heterojunction boundary, inhibiting carrier recombination processes and synergistically accelerating photocatalytic reaction beyond individual components. Herein, a novel type of 2D-2D heterostructure consisting of oxygen-doped carbon nitride (OCN) and ultrathin CoAl-layered double hydroxide (CoAl-LDH) with the aid of hydrogen bonding has been constructed via in situ growth method. The visible-light photocatalytic degradation efficiency of the hybridized photocatalyst is 38 and 239 folds higher than that of pure OCN and pure CoAl-LDH, respectively. This is due to the strong electronic coupling effect in the heterostructured interface, which induces photogenerated charge transfer from CoAl-LDH to OCN and make for the constrction of an interfacial internal electric field (IIEF) between CoAl-LDH and OCN. Based on the experimental evidence and density functional theory calculations, an IIEF-induced direct Z-scheme charge transfer mechanism has been proposed to enhance the extraction and utilization of photoinduced electron and hole in respectively CoAl-LDH and OCN. This work uncovers the nature of charge transfer system based on a 2D–2D heterostructured system, which can be potentially employed in various fields of photocatalysis.MOE (Min. of Education, S’pore)EDB (Economic Devt. Board, S’pore

Addressing molecular optomechanical effects in nanocavity-enhanced Raman scattering beyond the single plasmonic mode.

The description of surface-enhanced Raman scattering (SERS) as a molecular optomechanical process has provided new insights into the vibrational dynamics and nonlinearities of this inelastic scattering process. In earlier studies, molecular vibrations have typically been assumed to couple with a single plasmonic mode of a metallic nanostructure, ignoring the complexity of the plasmonic response in many configurations of practical interest such as in metallic nanojunctions. By describing the plasmonic fields as a continuum, we demonstrate here the importance of considering the full plasmonic response to properly address the molecule-cavity optomechanical interaction. We apply the continuum-field model to calculate the Raman signal from a single molecule in a plasmonic nanocavity formed by a nanoparticle-on-a-mirror configuration, and compare the results of optomechanical parameters, vibrational populations, and Stokes and anti-Stokes signals of the continuum-field model with those obtained from the single-mode model. Our results reveal that high-order non-radiative plasmonic modes significantly modify the optomechanical behavior under strong laser illumination. Moreover, Raman linewidths, lineshifts, vibrational populations, and parametric instabilities are found to be sensitive to the energy of the molecular vibrational modes. The implications of adopting the continuum-field model to describe the plasmonic cavity response in molecular optomechanics are relevant in many other nanoantenna and nanocavity configurations commonly used to enhance SERS

Research data supporting "Addressing Molecular Optomechanical Effects in Nanocavity-Enhanced Raman Scattering beyond the Single Plasmonic Mode"

In this folder, we include the original datasets for the figures in the article "Addressing Molecular Optomechanical Effects in Nanocavity-Enhanced Raman Scattering beyond the Single Plasmonic Mode" by Yuan Zhang, Ruben Esteban, Roberto A. Boto, Mattin Urbieta, Xabier Arrieta, ChongXin Shan, Shuzhou Li, Jeremy J. Baumberg and Javier Aizpurua, published in the journal Nanoscale (DOI: 10.1039/d0nr06649d). We organize the datasets with sub-folders, which are labeled with the figure number in the main article and the electronic supplementary information (ESI). In each sub-folder, the datasets are presented in text files named as "Figure[X].dat" (X for 2,3,...,S1,S2,...). The matlab scripts with name "Figure[X].m" import the text files to produce the figures in the main text and the ESI. In the begining of the scripts, we provide the explanation of the meaning of the columns in the datasets. The matlab files were prepared for version R2018b. Notice that the "Figure[X].m" can be opened with a standard word processor so that it is possible to read the explanation without using the matlab program. The data in "Figure[X].dat" can then be plotted using a different program.National Science Foundation of ChinaSpanish Ministry of Science and InnovationBasque GovernmentEuropean ComissionUK EPSRCPeer reviewe

Addressing molecular optomechanical effects in nanocavity-enhanced Raman scattering beyond the single plasmonic mode

The description of surface-enhanced Raman scattering (SERS) as a molecular optomechanical process has provided new insights into the vibrational dynamics and nonlinearities of this inelastic scattering process. In earlier studies, molecular vibrations have typically been assumed to couple with a single plasmonic mode of a metallic nanostructure, ignoring the complexity of the plasmonic response in many configurations of practical interest such as in metallic nanojunctions. By describing the plasmonic fields as a continuum, we demonstrate here the importance of considering the full plasmonic response to properly address the molecule-cavity optomechanical interaction. We apply the continuum-field model to calculate the Raman signal from a single molecule in a plasmonic nanocavity formed by a nanoparticle-on-a-mirror configuration, and compare the results of optomechanical parameters, vibrational populations, and Stokes and anti-Stokes signals of the continuum-field model with those obtained from the single-mode model. Our results reveal that high-order non-radiative plasmonic modes significantly modify the optomechanical behavior under strong laser illumination. Moreover, Raman linewidths, lineshifts, vibrational populations, and parametric instabilities are found to be sensitive to the energy of the molecular vibrational modes. The implications of adopting the continuum-field model to describe the plasmonic cavity response in molecular optomechanics are relevant in many other nanoantenna and nanocavity configurations commonly used to enhance SERS.We acknowledge project Nr. 12004344 from the National Science Foundation of China, joint project Nr. 21961132023 from the NSFC-DPG, project PID2019-107432GB-I00 from the Spanish Ministry of Science and Innovation, project KK-2019/00101 from Eusko Jaurlaritza, project H2020-FET Open “THOR” Nr. 829067 from the European Commission, UK EPSRC EP/L027151/1, and grant IT1164-19 for consolidated groups of the Basque University, through the Department of Education, Research and Universities of the Basque Government.Peer reviewe

Optomechanics with molecular vibrations in plasmonic nanocavities

Póster presentado al Quantum Nanophotonics, celebrado en el Centro de Ciencias de Benasque Pedro Pascual de forma online del 28 de febrero al 5 de marzo de 2021.Peer reviewe

Electrical promotion of spatially photoinduced charge separation via interfacial-built-in quasi-alloying effect in hierarchical Zn2In2S5/Ti3C2(O, OH)x hybrids toward efficient photocatalytic hydrogen evolution and environmental remediation

Exploring new hybridized catalysts for synergistically promoting the photocatalytic efficiency hold great challenges in solar-to-chemical energy conversion and environmental remediation. Hierarchical Zn2In2S5/Ti3C2(O, OH)x hybrids have been rationally constructed using Ti3C2(O, OH)x as a two-dimensional platform for in situ growth of flower-like Zn2In2S5 microsphere under anaerobically hydrothermal conditions. Upon exposure to visible light, the Zn2In2S5/Ti3C2(O, OH)x hybrids with the Ti3C2(O, OH)x content of 1.5% (by mass) had hydrogen generation yields of 12,983.8 μmol g−1, which was significantly better than that of pure Zn2In2S5. The apparent quantum efficiency reached 8.96% at 420 nm. Furthermore, the photocatalytic tetracycline removal rate was ˜1.25 times higher than that of pure Zn2In2S5, and can be further improved with the increase of temperature in the range of 35–55 °C. Excellent photocatalytic activity originated from the synergistic effects between visible-light-active Zn2In2S5 and conductive Ti3C2(O, OH)x for spatial electrical promotion. The photogenerated-electrons transfer efficiency from Zn2In2S5 to Ti3C2(O, OH)x was 33.0%. In accordance with spectroscopic, electrochemical, and density functional theory studies, we proposed that the interfacial-built-in quasi-alloying effect between ZIS and Ti3C2(O, OH)x culminated in notable charge redistribution, which thereby facilitated the spatial separation and transfer of photogenerated electron-hole pairs. This work revealed the underlying photo-excited charge transfer between metallic compound and semiconductor.Economic Development Board (EDB)Enterprise SingaporeMinistry of Education (MOE)The authors gratefully acknowledge the financial support provided by the Singapore Ministry of Education Academic Research Funds Tier 2 (MOE2014-T2-2-074; ARC16/15) and Tier 1 (2015-T1-001-023; RG7/15), the GSK (GlaxoSmithKline) – EDB (Economic Development Board) Trust Fund, and the Joint Singapore-Germany Research Project Fund (SGP-PROG3-019). We also acknowledge funding from the Projects of the National Nature Science Foundation of China (No. 21776066, 51708195). Hou Wang, Yuanmiao Sun and Yan Wu contributed equally to this work