bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency-extended inverse design of transmission-type linear-to-circular polarization control metasurface based on deep learning
Authors: Hu Yanwen , Ma Yaodong , Zhang Tingrong , Li Shoudong , Zhou Wenying
Published: May 2024

Due to the parameter range limitations of the training dataset, traditional inverse prediction network models can only predict structure parameters of the metasurface within a limited frequency range. When the given design targets exceed the prediction range of network models, the predicted results will not match the actual results. This paper proposes a frequency-extended inverse design method (FEIDM) based on deep learning to address the problem. The method can automatically collect the required data and train the network model based on the center working frequency of the design targets, thereby achieving accurate prediction of metasurface structural parameters and effectively reducing labor and computational costs. Taking the transmission-type linear-to-circular polarization control metasurface as an example, the unit cell of the metasurface is first established in the paper. The structural parameters and corresponding electromagnetic parameters are collected without changing the unit size of the metasurface, and an initial inverse prediction network model (IIPNM) is constructed. The research results indicate that its predictable center working frequency range is 3–5.5 GHz. Using the design concept proposed in this paper, a program is constructed, it can automatically achieve data collection, target extraction, network model training, and prediction. Four given design targets are predicted. Among them, the center working frequencies of the three design targets are outside the initial predictable range. The predicted results meet the requirements of the given target, verifying the effectiveness of the proposed scheme. Finally, a set of parameters is selected to fabricate, and the experimental results are consistent with the simulation results. The research results can provide a reference for the efficient prediction of metasurface structural parameters over a wide frequency band.
Design and analysis of K and Ku-band wide-angle polarization-insensitive dual-band perfect metamaterial absorber
Authors: Wang Chenglong , Ji Shijun , Zhao Ji , Liu Zhenze , Dai Handa
Published: May 2024

This paper presents a polarization-insensitive dual-band metamaterial perfect absorber applied to the Ku and K bands. The proposed dual-band metamaterial absorber (MMA) is a three-layer structure of metal-dielectric-metal. The top metal layer consists of a split circle ring, two intersecting square rings, and a circle ring, the bottom metal layer is made of copper, and the middle dielectric layer is made of FR-4. The simulation results show that the MMA has two absorption peaks at frequencies of 12.06 GHz and 19.07 GHz, with absorption rates of 99.95% and 99.73%, respectively. The MMA exhibits good polarization insensitivity in TE and TM modes. In TE mode, the increase in incident angle significantly broadens the absorption bandwidth. The experimental results verified the dual-band perfect absorption of MMA and the incident angle gain characteristic of TE mode. The proposed dual-band MMA can be applied in related fields such as radar antennas, satellite communication, and sensing.
Solution to a class of multistate Landau-Zener model beyond integrability conditions
Authors: Hu Rongyu , Li Fuxiang , Sun Chen
Published: May 2024

We study a class of multistate Landau-Zener model which cannot be solved by integrability conditions or other standard techniques. By analyzing analytical constraints on its scattering matrix and performing fitting to results from numerical simulations of the Schrödinger equation, we find nearly exact analytical expressions of all its transition probabilities for specific parameter choices. We also determine the transition probabilities up to leading orders of series expansions in terms of the inverse sweep rate (namely, in the diabatic limit) for general parameter choices. We further show that this model can describe a Su-Schrieffer-Heeger chain with couplings changing linearly in time. Our work presents a new route, i.e., analytical constraint plus fitting, to analyze those multistate Landau-Zener models which are beyond the applicability of conventional solving methods.
Ultra-thin wideband frequency tunable metamaterial absorber and its application for antenna radar cross section reduction
Authors: Luo Heng , Zheng Jinfei , Wang Zhen , Wang Meng , He Jun , Dong Jian
Published: May 2024

A metamaterial absorber (MMA) with broadband and efficient absorption performance based on ultra-thin dielectric layer is proposed. In this unique configuration, the absorption frequency of the MMA can be continuously and dynamically tuned across a wide frequency range by manipulating the reverse voltage of the central varactor diode. From both the equivalent circuit and field distribution perspectives, we analyze the mechanisms behind broadband tuning and superior absorption. Simulation and experimental results demonstrate that the absorption peak of MMA can be continuously tuned over a range of 5.16–8.16 GHz, with the absorption rate consistently exceeding 90%, and the thickness is only 0.5 mm. Integrating MMA array with a microstrip patch antenna in a suitable manner can dynamically mitigates the radar cross section (RCS) within the associated frequency range, with virtually negligible impact on the antenna’s radiation performance.
Gravitational redshift constraints on the effective theory of interacting dark energy
Authors: Castello Sveva , Mancarella Michele , Grimm Nastassia , Sobral-Blanco Daniel , Tutusaus Isaac , Bonvin Camille
Published: May 2024

Upcoming galaxy surveys provide the necessary sensitivity to measure gravitational redshift, a general relativistic effect that generates a dipole in galaxy clustering data when correlating two distinct populations of galaxies. Here, we study the constraining power of gravitational redshift within the framework of the effective theory of interacting dark energy. This formalism describes linear cosmological perturbations in scalar-tensor theories of gravity with a limited number of free functions, and allows each particle species to be coupled differently to the gravitational sector. In this work, we focus on Horndeski theories with a non-minimal coupling of dark matter to the scalar degree of freedom, yielding a breaking of the weak equivalence principle for this cosmic component, a scenario that is yet untested. We show that the dipole generated by gravitational redshift significantly breaks degeneracies and tightens the constraints on the parameters of the effective theory compared to the standard redshift-space distortion analysis solely based on the even multipoles in the galaxy correlation function, with an improvement of up to ∼ 50% for populations with a galaxy bias difference equal to 1. We make the Python package EF-TIGRE (Effective Field Theory of Interacting dark energy with Gravitational REdshift) developed for this work publicly available (https://github.com/Mik3M4n/EF-TIGRE).
Foreground removal with ILC methods for AliCPT-1
Authors: Dou Jiazheng , Ghosh Shamik , Santos Larissa , Zhao Wen
Published: May 2024

One of the main goals of most future CMB experiments is the precise measurement of CMB B-mode polarization, whose major obstacle is the Galactic foregrounds. In this paper, we evaluate the foreground cleaning performance of the variants of the ILC method on partial sky B-modes and analyze the main sources of biases on the BB power spectrum. Specially, we compare the NILC, the cILC (in three domains) and the cMILC methods for AliCPT-1 simulations. We find that the cILC methods implemented in harmonic space and needlet space are both competent to clean different models of foregrounds, which bias the tensor-to-scalar ratio about 0.008 at maximum, and constrain the tensor-to-scalar ratio to r < 0.043(95%CL) for the AliCPT-1 configuration. We also note that the deviation of the estimated noise bias from the actual one for ILC, dubbed the noise bias error (NBE) in this paper, might make significant effects on the power spectrum for a small footprint and low signal-to-noise ratio CMB experiment. We finally obtain its relation with respect to the noise residual which fits well with the simulated results.
Comment on “Source of black bounces in Rastall gravity”
Authors: Rodrigues Manuel E. , Silva Marcos V.de S.
Published: May 2024

In Atazadeh and Hadi (JCAP
01 (2024) 067), the authors proposed that black bounce solutions, such as the Simpson-Visser and the Bardeen-type spacetimes, can be obtained from Rastall gravity. To achieve these spacetimes, the authors consider the presence of a phantom scalar field with nonlinear electrodynamics. However, in this comment, we obtained different electromagnetic Lagrangians from the original work. The most problematic issue is not the incorrect expression of the electromagnetic Lagrangian itself. We show that the method obtains electromagnetic functions that are inconsistent. To obtain the black bounce spacetimes as solutions of Rastall gravity, it is necessary to consider an isotropic fluid, combined with the nonlinear electrodynamics and the phantom scalar field.
Gravitational wave measurement in the mid-band with atom interferometers
Authors: Baum Sebastian , Bogorad Zachary , Graham Peter W.
Published: May 2024

Gravitational Waves (GWs) have been detected in the ∼ 100 Hz and nHz bands, but most of the gravitational spectrum remains unobserved. A variety of detector concepts have been proposed to expand the range of observable frequencies. In this work, we study the capability of GW detectors in the “mid-band”, the ∼ 30 mHz– 10 Hz range between LISA and LIGO, to measure the signals from and constrain the properties of ∼ 1 – 100 M
⊙ compact binaries. We focus on atom-interferometer-based detectors. We describe a Fisher matrix code, AIMforGW, which we created to evaluate their capabilities, and present numerical results for two benchmarks: terrestrial km-scale detectors, and satellite-borne detectors in medium Earth orbit. Mid-band GW detectors are particularly well-suited to pinpointing the location of GW sources on the sky. We demonstrate that a satellite-borne detector could achieve sub-degree sky localization for any detectable source with chirp mass ℳ
c
≲ 50 M
⊙. We also compare different detector configurations, including different locations of terrestrial detectors and various choices of the orbit of a satellite-borne detector. As we show, a network of only two terrestrial single-baseline detectors or one single-baseline satellite-borne detector would each provide close-to-uniform sky-coverage, with signal-to-noise ratios varying by less than a factor of two across the entire sky. We hope that this work contributes to the efforts of the GW community to assess the merits of different detector proposals.
Dissecting the stochastic gravitational wave background with astrometry
Authors: Çalışkan Mesut , Chen Yifan , Dai Liang , Kumar Neha Anil , Stomberg Isak , Xue Xiao
Published: May 2024

Astrometry, the precise measurement of star motions, offers an alternative avenue to investigate low-frequency gravitational waves through the spatial deflection of photons, complementing pulsar timing arrays reliant on timing residuals. Upcoming data from Gaia, Theia, and Roman can not only cross-check pulsar timing array findings but also explore the uncharted frequency range bridging pulsar timing arrays and LISA. We present an analytical framework to evaluate the feasibility of detecting a gravitational wave background, considering measurement noise and the intrinsic variability of the stochastic background. Furthermore, we highlight astrometry's crucial role in uncovering key properties of the gravitational wave background, such as spectral index and chirality, employing information-matrix analysis. Finally, we simulate the emergence of quadrupolar correlations, commonly referred to as the generalized Hellings-Downs curves.
Topological phase transition in compressed van der Waals superlattice heterostructure BiTeCl/HfTe2
Authors: Li 李 Zhilei 志磊 , Li 李 Yinxiang 殷翔 , Wang 王 Yiting 奕婷 , Chen 陈 Wenzhi 文执 , Chen 陈 Bin 斌
Published: May 2024

Based on first-principles calculations, we investigate the electronic band structures and topological properties of heterostructure BiTeCl/HfTe2 under c-direction strain. In the primitive structure, this material undergoes a phase transition from an insulator with a narrow indirect gap to a metal by strong spin–orbital coupling. When strain effect is considered, band inversion at time-reversal invariant point Z is responsible for the topological phase transition. These nontrivial topologies are caused by two different types of band crossings. The observable topological surface states in (110) surface also support that this material experiences topological phase transition twice. The layered heterostructure with van der Waals force provides us with a new desirable platform upon which to control topological phase transition and construct topological superconductors.
High-visibility ghost imaging with phase-controlled discrete classical light sources
Authors: Wu 仵 Xueying 雪滢 , Zhao 赵 Yue 岳 , Li 李 Liming 利明
Published: May 2024

We take phase modulation to create discrete phase-controlled sources and realize the super-bunching effect by a phase-correlated method. From theoretical and numerical simulations, we find the space translation invariance of the bunching effect is a key point for the ghost imaging realization. Experimentally, we create the orderly phase-correlated discrete sources which can realize high-visibility second-order ghost imaging than the result with chaotic sources. Moreover, some factors affecting the visibility of ghost image are discussed in detail.
Optimization of pellet design parameters to achieve deep fueling depth in EAST plasma with PAM code
Authors: Zhang Jie , Hou Jilei , Liu Zhuang , Chen Jiale , Huang Jia , Zhuang Ge , Chan Vincent , Nan Kaibo , Zheng Yifeng , Wu Xiaohe , Zhou Yinan , Yolbarsop Adili , Zhou Chengxi , Zhang Qi , Zhang Yunjiao , Qiang Ziwei , Deng Peng , Qiu Meng , Zhang Jingshuo , Pan Di , Dong Qilong , Li Dazheng , Yu Yangdi , Mao Xiaowei , Lan Tao , Liu Zixi , Liu Jian , Liu Adi
Published: May 2024

Deep pellet fueling depth is necessary to achieve a high-density high confinement operation and to conduct some pellet-related researches in current devices, such as trigger of internal transport barrier, and to achieve high fusion power and tritium burn-up fraction in future fusion devices. The newly developed PAM code which can make a fast evaluation on pellet ablation and deposition is applied to optimize injection parameters to achieve deep pellet fueling. Systematic scans on pellet injection parameters including pellet injection positions, injection angles, sizes and speeds are performed for optimization purpose, while at the same time demonstrating flexibility and time efficiency of the PAM code. Dependences of the pellet fueling depth on these injection parameters are revealed by simulation results and analyzed. Simulation results indicate that pellet penetration contributes more to the deep pellet deposition than the

∇
B

-induced plasmoid drifts in low temperature plasmas, while deep pellet fueling in reactor relevant high temperature plasmas has to rely on plasmoid drifts. Though a shallow penetration is expected in high temperature plasmas, the

∇
B

-induced plasmoid drift is expected to be larger than that in relatively low temperature plasmas.
Scintillation of Ar/CF4 mixtures: glass-THGEM characterization with 1% CF4 at 1–1.5 bar
Authors: Amedo P. , Hafeji R. , Roberts A. , Lowe A. , Ravinthiran S. , Leardini S. , Majumdar K. , Mavrokoridis K. , González-Díaz D.
Published: May 2024

Argon gas doped with 1% wavelength-shifter (CF4) has been employed in an optical time projection chamber (OTPC) to image cosmic radiation. We present results obtained during the system commissioning, performed with two stacked glass thick gaseous electron multipliers (THGEMs) and an electron-multiplying charge coupled device (EMCCD camera) at 1 bar. Preliminary estimates indicate that the combined optical gain was of the order of 106 (ph/e), producing sharp and high-contrast raw images without resorting to any filtering or post-processing. A first assessment of the impact of pressurization showed no change in the attainable gains when operating at 1.5 bar.
Comparison of point cloud and image-based models for calorimeter fast simulation
Authors: Torales Acosta Fernando , Mikuni Vinicius , Nachman Benjamin , Arratia Miguel , Karki Bishnu , Milton Ryan , Karande Piyush , Angerami Aaron
Published: May 2024

Score based generative models are a new class of generative
models that have been shown to accurately generate high dimensional
calorimeter datasets. Recent advances in generative models have used
images with 3D voxels to represent and model complex calorimeter
showers. Point clouds, however, are likely a more natural
representation of calorimeter showers, particularly in calorimeters
with high granularity. Point clouds preserve all of the information
of the original simulation, more naturally deal with sparse
datasets, and can be implemented with more compact models and data
files. In this work, two state-of-the-art score based models are
trained on the same set of calorimeter simulation and directly
compared.
Promoting tissue repair using deferoxamine nanoparticles loaded biomimetic gelatin/HA composite hydrogel
Authors: Li Jing , Lu Xiang , Weng Mengjia , Wang Yiru , Tang Jun , Xu Qian , Zhang Lei , Bai Jiaojiao
Published: May 2024

To effectively address underlying issues and enhance the healing process of hard-to-treat soft tissue defects, innovative therapeutic approaches are required. One promising strategy involves the incorporation of bioactive substances into biodegradable scaffolds to facilitate synergistic tissue regeneration, particularly in vascular regeneration. In this study, we introduce a composite hydrogel design that mimics the extracellular matrix by covalently combining gelatin and hyaluronic acid (HA), with the encapsulation of deferoxamine nanoparticles (DFO NPs) for potential tissue regeneration applications. Crosslinked hydrogels were fabricated by controlling the ratio of HA in the gelatin-based hydrogels, resulting in improved mechanical properties, enhanced degradation ability, and optimised porosity, compared with hydrogel formed by gelatin alone. The DFO NPs, synthesized using a double emulsion method with poly (D,L-lactide-co-glycolide acid), exhibited a sustained release of DFO over 12 d. Encapsulating the DFO NPs in the hydrogel enabled controlled release over 15 d. The DFO NPs, composite hydrogel, and the DFO NPs loaded hydrogel exhibited excellent cytocompatibility and promoted cell proliferation in vitro. Subcutaneous implantation of the composite hydrogel and the DFO NPs loaded hydrogel demonstrated biodegradability, tissue integration, and no obvious adverse effects, evidenced by histological analysis. Furthermore, the DFO NPs loaded composite hydrogel exhibited accelerated wound closure and promoted neovascularisation and granular formation when tested in an excisional skin wound model in mice. These findings highlight the potential of our composite hydrogel system for promoting the faster healing of diabetes-induced skin wounds and oral lesions through its ability to modulate tissue regeneration processes.
Recent advances in hepatocellular carcinoma-targeted nanoparticles
Authors: Liu Xiaoming , Bai Yaowei , Zhou Binqian , Yao Wei , Song Songlin , Liu Jiacheng , Zheng Chuansheng
Published: May 2024

In the field of medicine, we often brave the unknown like interstellar explorers, especially when confronting the formidable opponent of hepatocellular carcinoma (HCC). The global burden of HCC remains significant, with suboptimal treatment outcomes necessitating the urgent development of novel drugs and treatments. While various treatments for liver cancer, such as immunotherapy and targeted therapy, have emerged in recent years, improving their transport and therapeutic efficiency, controlling their targeting and release, and mitigating their adverse effects remains challenging. However, just as we grope through the darkness, a glimmer of light emerges—nanotechnology. Recently, nanotechnology has attracted attention because it can increase the local drug concentration in tumors, reduce systemic toxicity, and has the potential to enhance the effectiveness of precision therapy for HCC. However, there are also some challenges hindering the clinical translation of drug-loaded nanoparticles (NPs). Just as interstellar explorers must overcome interstellar dust, we too must overcome various obstacles. In future researches, the design and development of nanodelivery systems for novel drugs treating HCC should be the first attention. Moreover, researchers should focus on the active targeting design of various NPs. The combination of the interventional therapies and drug-loaded NPs will greatly advance the process of precision HCC therapy.
Normal quantum channels and Markovian correlated two-qubit quantum errors
Authors: Contreras Reynoso Alejandro , Gorin Thomas
Published: May 2024

We study general ‘normally’ (Gaussian) distributed random unitary transformations. These distributions can be defined in terms of a diffusive random walk in the respective group manifold. On the one hand, a Gaussian distribution induces a unital quantum channel, which we will call ‘normal’. On the other hand, the diffusive random walk defines a unital quantum process, generated by a Lindblad master equation. In the single qubit case, we show different distributions may induce the same quantum channel.
In the case of two qubits, we study normal quantum channels, induced by Gaussian distributions in

SU
(
2
)
⊗
SU
(
2
)

. They provide an appropriate framework for modeling quantum errors with classical correlations. In contrast to correlated Pauli errors, for instance, they conserve their Markovianity, and they lead to very different results in error correcting codes. This is illustrated with an application to entanglement distillation.
Optimal quantum metrology of two-photon absorption
Authors: Karsa Athena , Nair Ranjith , Chia Andy , Lee Kwang-Geol , Lee Changhyoup
Published: May 2024

Two-photon absorption (TPA) is a nonlinear optical process with wide-ranging applications from spectroscopy to super-resolution imaging. Despite this, the precise measurement and characterisation of TPA parameters are challenging due to their inherently weak nature. We study the potential of single-mode quantum light to enhance TPA parameter estimation through the quantum Fisher information (QFI). Discrete variable quantum states (defined to be a finite superposition of Fock states) are optimised to maximise the QFI for given absorption, revealing a quantum advantage compared to both the coherent state (classical) benchmark and the single-mode squeezed vacuum state. For fixed average energy

n
¯

∈
2

N

, the Fock state is shown to be optimal for large TPA parameters, while a superposition of vacuum and a particular Fock state is optimal for small absorption for all

n
¯

. This differs from single-photon absorption where the Fock state is always optimal. Notably, photon counting is demonstrated to offer optimal or nearly optimal performance compared to the QFI bound for all levels of TPA parameters for the optimised quantum probes, and their quantum advantage is shown to be robust to single-photon loss. Our findings provide insight into known limiting behaviours of Gaussian probes and their different FI scalings under photon counting (

∝

n
¯

2

for squeezed vacuum states versus

n
¯

3

for coherent states). The squeezed state outperforms coherent states for small TPA parameters but underperforms in the intermediate regime, becoming comparable in the large absorption limit. This can be explained through fundamental differences between behaviours of even and odd number Fock states: the former’s QFI diverges in both large and small absorption limits, while the latter diverges only in the small absorption limit, dominating at intermediate scales.
Resource-efficient quantum principal component analysis
Authors: Wang Youle , Luo Yu
Published: May 2024

Principal component analysis (PCA) is an important dimensionality reduction method in machine learning and data analysis. Recently, the quantum version of PCA has been established to diagonalize quantum states. Although these quantum algorithms promise quantum advantages, they require substantial resources beyond the reach of state-of-the-art quantum technologies. This work aims to reduce resource requirements and improve the efficiency of quantum PCA. Assuming that the quantum state is accessed through a purified quantum query model and a sampling model, we propose quantum algorithms that use minimal resource requirements for ancillary qubits to reveal properties of eigenvectors and eigenvalues of a state. In particular, we show that estimating eigenvalue λ with error ε and success probability larger than

λ
(
1
−
η
)

requests a query complexity

O
~

(

ϵ

−
1

)

and a sample complexity

O
~

(

ϵ

−
2

η

−
1

)

, respectively. To our knowledge, our result is the first quantum speedup that achieves asymptotic linear scaling in

1

/

ϵ

for quantum PCA. As applications, we discuss estimating the minimum relative entropy of entanglement of bipartite pure-states and performing quantum state discrimination tasks. We show that quantum speedups are maintained when the pure state has a low Schmidt number and states of discrimination have a low rank. This study opens up a new quantum PCA method for high-dimensional quantum data analysis and discusses its application in quantum information processing tasks.
Unifying quantum verification and error-detection: theory and tools for optimisations
Authors: Kapourniotis Theodoros , Kashefi Elham , Leichtle Dominik , Music Luka , Ollivier Harold
Published: May 2024

With the advent of cloud-based quantum computing, it has become vital to provide strong guarantees that computations delegated by clients to quantum service providers have been executed faithfully. Secure—blind and verifiable—delegated quantum computing (SDQC) has emerged as one of the key approaches to address this challenge, yet current protocols lack at least one of the following three ingredients: composability, noise-robustness and modularity. To tackle this question, our paper lays out the fundamental structure of SDQC protocols, namely mixing two components: the computation which the client would like the server to perform and tests that are designed to detect a server’s malicious behaviour. Using this abstraction, our main technical result is a set of sufficient conditions on these components which imply the security and noise-robustness of generic SDQC protocols in the composable Abstract Cryptography framework. This is done by establishing a correspondence between these security properties and the error-detection capabilities of the test computations. Changing the types of tests and how they are mixed with the client’s computation automatically yields new SDQC protocols with different security and noise-robustness capabilities. This approach thereby provides the desired modularity as our sufficient conditions on test computations simplify the steps required to prove the security of the protocols and allows to focus on the design and optimisation of test rounds to specific situations. We showcase this by systematising the search for improved SDQC protocols for bounded-error quantum polynomial-time (

BQP

) computations. The resulting protocols do not require more hardware on the server’s side than what is necessary to blindly delegate the computation without verification, and they outperform all previously known results.
Application of handheld/portable spectroscopic tools to the identification, inner stratigraphy and mapping of archaeological metal artefacts
Authors: Mattiello Sara , De Pascale Olga , Palleschi Vincenzo , Fiorentino Girolamo , Senesi Giorgio S
Published: May 2024

Field handheld/portable instrumentations, such as in-situ geochemical analyzers, have the potential to assist efficiently targeted geochemical archaeometry campaigns in detecting and quantifying specific elements. Non-destructive portable energy dispersive x-ray fluorescence and micro-destructive handheld laser-induced breakdown spectroscopy (LIBS) instrumentation were utilized to investigate the elemental composition, internal stratigraphy by depth profiling and microscale compositional mapping of five copper and two iron alloy artefacts collected from various ancient graves in the Minervino Murge area, Apulia, Italy. The primary elements identified by both techniques included Cu, Sn and Pb in copper alloys, and Fe with minor amounts of Cu and Pb in iron alloys. Furthermore, the elements Al, Ca, Si, Mg, Na and K, mostly originated from soil contamination, and the trace elements Sb, Ni and Zn were detected. The satisfactory performance of both techniques was assessed by their capacity to provide reproducible elemental composition data. Finally, the depth profile and mapping achieved by LIBS contributed to understanding the metal processing and history of the objects studied, so confirming both techniques to be robust analytical tools in outdoor archaeology and archaeometry campaigns.
Speed of sound measurement and mapping in transparent materials by impulsive stimulated Brillouin microscopy
Authors: Le Taoran , Li Jiarui , Wei Haoyun , Li Yan
Published: May 2024

Impulsive stimulated Brillouin scattering (ISBS) is a variant of stimulated Brillouin scattering, which can overcome the shortcomings of the long acquisition time of traditional Brillouin microscopy. We introduce the difference between ISBS and other Brillouin microscopies in calculating longitudinal modulus. The Brillouin frequency shift obtained by ISBS is only related to the system parameters and the speed of sound (SOS) in the sample, not to the refractive index. Non-contact SOS measurement of homogeneous samples is an important application of Brillouin scattering, used in the early study of Brillouin spectroscopy and the mechanical properties of liquids. However, the measurement requires prior knowledge of the sample refractive index, which limits the measurement of the unknown refractive index sample. Here, we propose a method to measure the SOS based on ISBS, which in principle avoids the need for refractive index parameters. The SOS of several liquids are measured and compared with the standard values. The mean relative standard deviation is 1.13%. Moreover, we measure the SOS of a mixture of ethanol and water to demonstrate an application of measuring SOS without refractive index information. We also demonstrate the high spatial resolution of ISBS with a methanol-filled PDMS sample.
Investigation of cathode properties of two-dimensional NbS2Cl2 for Li and Na-ion batteries using density functional theory
Authors: Raj Natarajan Arul , S Pujari Bhalchandra , Vaitheeswaran G , Kanchana V
Published: May 2024

Exploring novel two-dimensional materials (2D) for electrode and electrochemical storage applications stands as a pivotal pursuit in advancing renewable energy technologies. While recent research has predominantly focused on anode materials, cathode materials have received comparatively lesser attention. This study delves into the potential cathode applications of the novel two-dimensional material NbS2Cl2 using density functional theory. Fundamental properties, encompassing electronic and thermodynamic attributes, were scrutinized to comprehend the material’s characteristics. Our investigation extended to examining the adsorption and diffusion properties of these electrode materials. Comprehensive calculations of mechanical and thermodynamic properties reaffirmed the stability of this system. Upon adsorption of Li/Na atoms, the conducting nature emerged, evident through charge density difference and projected density of states. Our findings notably reveal minimal diffusion barriers of 1.5 eV and 0.35 eV for Li and Na atoms. Moreover, the observed open circuit voltages for adsorbed Li and Na ions were 4.69 V and 2.62 V, respectively. The calculated theoretical capacity for adsorbed Li-ion on 2D-NbS2Cl2 is 400 mAh g−1, while for Na-ion adsorption, it is 353 mAh g−1, awaiting validation through future experimental verifications.
Excited-state downfolding using ground-state formalisms
Authors: Bauman Nicholas P
Published: May 2024

Downfolding coupled cluster (CC) techniques are powerful tools for reducing the dimensionality of many-body quantum problems. This work investigates how ground-state downfolding formalisms can target excited states using non-Aufbau reference determinants, paving the way for applications of quantum computing in excited-state chemistry. This study focuses on doubly excited states for which canonical equation-of-motion CC approaches struggle to describe unless one includes higher-than-double excitations. The downfolding technique results in state-specific effective Hamiltonians that, when diagonalized in their respective active spaces, provide ground- and excited-state total energies (and therefore excitation energies) comparable to high-level CC methods. The performance of this procedure is examined with doubly excited states of H2, Methylene, Formaldehyde, and Nitroxyl.
Africa’s critical minerals can power the global low-carbon transition
Authors: Ouedraogo N S , Kilolo J M M
Published: May 2024

The global shift towards low-carbon economies and societies is expected to result in a substantial surge in the demand for critical minerals. Endowed with at least a fifth of the world’s reserves in a dozen minerals, Africa can play a pivotal role in facilitating the global transition away from fossil fuels. In this paper, we argue that, for this to happen, Africa needs to act now to convert its natural assets into sustainable comparative advantages for a resource-based industrialisation. This will require proactive measures to ensure strict compliance with the highest standards of governance and transparency, as well as to uphold social values such as safeguarding basic rights of affected individuals and communities and sound environmental management to avoid falling into a new resource curse. This also requires a renewed global raw material diplomacy in which Africa manages the geopolitics of critical minerals, identifying strategic global alliances to unleash economic potential, create local content in the mining sector, develop domestic productive capacity, and foster sustainable development.
Non local analytical and numerical modelling of re-entrant auxetic honeycomb
Authors: Bora Kaustav Moni , Varshney Shailendra Kumar , Kumar Cheruvu Siva
Published: May 2024

Auxetic materials, characterized by their negative Poisson’s ratio, have been extensively studied for applications in energy absorption and mechanical reinforcement. Re-entrant honeycomb structures, a subtype of auxetic materials, have demonstrated superior mechanical characteristics. However, understanding the mechanical behavior of these structures at the nanoscale remained a significant challenge. To address this gap, the authors explored the influence of size on the deflection behavior of re-entrant auxetic honeycomb structures through non-local continuum mechanics. Their analytical model, incorporating the Euler-Bernoulli beam model and considering four non-dimensional geometrical parameters, was validated through numerical simulations and a comprehensive review of existing literature. The study aimed to provide valuable insights into the design and engineering of re-entrant auxetic honeycomb structures across diverse applications, contributing to the advancement of non-local elasticity theory and deepening the understanding of the mechanical behavior of auxetic structures at the nanoscale. The research laid a foundation for further exploration and optimization of re-entrant honeycomb structures, facilitating their effective utilization in fields such as MEMS/NEMS by leveraging the dimensionless parameters identified in the study.
The methylome of motile cilia
Authors: King Stephen M. , Sakato-Antoku Miho , Patel-King Ramila S. , Balsbaugh Jeremy L.
Published: May 2024

Cilia are highly complex motile, sensory, and secretory organelles that contain perhaps 1000 or more distinct protein components, many of which are subject to various posttranslational modifications such as phosphorylation, N-terminal acetylation, and proteolytic processing. Another common modification is the addition of one or more methyl groups to the side chains of arginine and lysine residues. These tunable additions delocalize the side-chain charge, decrease hydrogen bond capacity, and increase both bulk and hydrophobicity. Methylation is usually mediated by S-adenosylmethionine (SAM)-dependent methyltransferases and reversed by demethylases. Previous studies have identified several ciliary proteins that are subject to methylation including axonemal dynein heavy chains that are modified by a cytosolic methyltransferase. Here, we have performed an extensive proteomic analysis of multiple independently derived cilia samples to assess the potential for SAM metabolism and the extent of methylation in these organelles. We find that cilia contain all the enzymes needed for generation of the SAM methyl donor and recycling of the S-adenosylhomocysteine and tetrahydrofolate byproducts. In addition, we find that at least 155 distinct ciliary proteins are methylated, in some cases at multiple sites. These data provide a comprehensive resource for studying the consequences of methyl marks on ciliary biology.
Litigating Climate Change in the Global South
Authors: Lin Jolene , Peel Jacqueline
Published: May 2024

While climate change litigation in developed countries of the ‘Global North’ is a well-studied phenomenon, relatively few studies focus on climate case law emerging in the Global South, its distinctive characteristics, and the contribution it is making, and may make, to implementation of international climate laws like the Paris Agreement. The purpose of this book is to shed light on emerging and accelerating climate litigation in Global South developing countries. It is the first monograph-length work to provide a comprehensive assessment of this jurisprudence. The book examines which Global South countries are seeing climate cases, what is driving these trends, the coalitions of actors involved, and the early impacts the litigation is delivering towards goals of climate mitigation and adaptation. With growing scholarly and policy interest in the contribution of climate litigation to international climate governance, the book helps capture and analyse the richness of climate cases emerging in the Global South to provide a holistic picture of the role climate litigation plays in addressing the global problem of climate change.
Revisiting and Understanding Crown Liability from a Historical Constitutional Perspective
Authors: Fortin Marie-France
Published: May 2024

In this chapter, the evolution of the understanding of the king can do no wrong in light of this book’s model is outlined. A discussion of current legal thinking in relation to crown liability is presented, informed by the historical constitutional approach adopted in this book. An analysis of the king can do no wrong as an ahistorical basis for crown immunity is conducted. Dicey’s influence on the current understanding of crown liability and on the Crown Proceedings Act 1947 (and its Canadian counterpart, the Crown Liability and Proceedings Act) is discussed. A possible reorientation of our understanding of the crown and of crown liability is suggested, based on a historically informed understanding of the king can do no wrong. The chapter concludes by highlighting the divergence in constitutional thinking in the realms of judicial review, the prerogative, the law of public authorities’ liability, and crown liability.
Complicit Participation
Authors: Preston Carrie J
Published: May 2024

Complicit participation is the prevailing framework through which white liberal allies participate in theatrical and other institutional efforts associated with “diversity, equity, and inclusion” initiatives. This book argues that the current trend of inviting audiences to participate in antiracist theater can lead to intense emotional experiences and insight; but it can also assure participants that they are an enlightened group of allies who are battling racism from their seats in the theater—without the inconvenience of engaging in activism or giving up their privilege. The book addresses immersive, documentary, site-specific, experimental, street, and popular theater in chapters on Jean Genet’s The Blacks, Branden Jacobs-Jenkins’s An Octoroon, George C. Wolfe’s Shuffle Along, Lin-Manuel Miranda’s Hamilton, Anna Deavere Smith’s Notes from the Field, and Claudia Rankine’s The White Card. The author analyzes her own complicit participation and that of other audience members and theater professionals in productions of these plays and their talkbacks or other audience engagement programs. While white allyship is often a shallow, even defensive performance that enables white supremacy, this does not mean we should abandon the work to dismantle institutionalized racism and advance social justice and equity. Instead, this book argues that recognizing the contradictions and complicities at the heart of allyship, inclusion, and diversity initiatives, as revealed in contemporary theater, can lay the groundwork for full and radical participation in antiracist efforts.
Dion Boucicault’s The Octoroon and the Loudly Immersed Audiences of Nineteenth-Century Melodramas
Authors: Preston Carrie J
Published: May 2024

This chapter presents melodramatic audience participation in Dion Boucicault’s 1859 The Octoroon as part of the prehistory of immersive theater that is more frequently associated with modernist and especially postmodern performance than with the supposedly conservative, sentimental genre of melodrama. When Brandon Jacobs-Jenkins adapted Boucicault’s melodrama in his controversial 2016 play, An Octoroon, he recognized that melodrama was rarely used to promote transformative politics, but it developed strategies for involving audiences in political questions. For this reason, melodrama appeals to contemporary playwrights like Jacobs-Jenkins, who are deeply engaged with antiracist politics but refuse the tendency to offer solutions or easy answers. Nineteenth-century melodrama is part of the overlooked history of immersive or site-specific theater, and theater artists from Jacobs-Jenkins to George C. Wolfe, Lin-Manuel Miranda to Claudia Rankine, turn back to the participatory conventions of melodrama for their own political theater work.
Doing Time in Anna Deavere Smith’s Act II
Authors: Preston Carrie J
Published: May 2024

Anna Deavere Smith’s Notes from the Field: Doing Time in Education, performed in 2016 at American Repertory Theater (A.R.T.) in Cambridge, Massachusetts, may have inspired A.R.T.’s Act II “experiment in disrupting the role of spectator as passive observer.” After the first act of Smith’s unique monologue performances drawn from actual interviews, facilitators separated audiences into small groups and asked them to share their own experiences with racial oppression and privilege. Following these Act II discussions, audiences returned to the theater for a moving Coda, but were they inspired to engage in political activism? Or was it just another talkback? This chapter argues that Act II was actually twenty-five minutes of immersive theater, bookended by an adamantly documentary form, and advertised as activism.
Playing The White Card with Claudia Rankine
Authors: Preston Carrie J
Published: May 2024

Claudia Rankine’s The White Card (2018) demonstrates that theater of racial justice, even with an Act II, cannot avoid contributing to the phenomenon the play documents so well—the tendency of art and media to turn Black suffering into spectacle. The play participates in the phenomenon, even as it reveals that the interest in depictions of Black suffering and death by liberal elites is yet another manifestation of white supremacy. The Act II talkback asked audiences to stay in the theater for a conversation about race, a conversation that gave audiences the opportunity to share, process, and perform their outrage at atrocity and their frustration with the more subtle forms of racism displayed by the well-intentioned white characters. In arguing that plays, theatrical institutions, and well-intentioned audience members are complicit in the systems they attempt to critique, this chapter reveals the infusion of white supremacy through every institution and the insidious, adaptable nature of both racism and diversity platforms. Recognizing the contradictions and complicities at the heart of allyship can begin to set the stage for full and radical participation in activist efforts.
Scoring alignments by embedding vector similarity
Authors: Ashrafzadeh Sepehr , Golding G Brian , Ilie Silvana , Ilie Lucian
Published: May 2024

Sequence similarity is of paramount importance in biology, as similar sequences tend to have similar function and share common ancestry. Scoring matrices, such as PAM or BLOSUM, play a crucial role in all bioinformatics algorithms for identifying similarities, but have the drawback that they are fixed, independent of context. We propose a new scoring method for amino acid similarity that remedies this weakness, being contextually dependent. It relies on recent advances in deep learning architectures that employ self-supervised learning in order to leverage the power of enormous amounts of unlabelled data to generate contextual embeddings, which are vector representations for words. These ideas have been applied to protein sequences, producing embedding vectors for protein residues. We propose the E-score between two residues as the cosine similarity between their embedding vector representations. Thorough testing on a wide variety of reference multiple sequence alignments indicate that the alignments produced using the new $E$-score method, especially ProtT5-score, are significantly better than those obtained using BLOSUM matrices. The new method proposes to change the way alignments are computed, with far-reaching implications in all areas of textual data that use sequence similarity. The program to compute alignments based on various $E$-scores is available as a web server at e-score.csd.uwo.ca. The source code is freely available for download from github.com/lucian-ilie/E-score.
Assessing GPT-4’s diagnostic accuracy with darker skin tones: underperformance and implications
Authors: Akuffo-Addo Edgar , Samman Luna , Munawar Leena , Akbik Maya , Kokikian Nelly , Wescott Raquel , Wu Jashin J
Published: May 2024

This study aimed to assess the accuracy of GPT-4 in generating appropriate differential diagnoses and arriving at the correct diagnoses for common skin lesions. Additionally, we investigated any differences in its diagnostic accuracy between darker and lighter skin tones. GPT-4 exhibited better performance in providing the correct diagnosis for lighter skin tones (44%, n = 11 of 25) compared with darker skin tones (12%, n = 3 of 25), and this was statistically significant (P < 0.05). Furthermore, with each unit increase in the Fitzpatrick scale, GPT-4’s performance decreased by 11.4% in accurately providing a differential diagnosis and by 7.1% in accurately providing the correct diagnosis.