bluuebunny/crossref_metadata_2025_split huggingface dataset:
Active stiffness tuning of lattice metamaterials
Authors: Mostofizadeh Parham , Dorey Robert A , Mohagheghian Iman 
Published: April 2024

Abstract
In this paper, surface conductive heating was utilized to actively control the stiffness of lattice metamaterials manufactured employing multi-material 3D printing. To create an electrical surface conduction, additively manufactured samples in single and dual material configurations were dip coated in a solution of carbon black in water. Electro-thermo-mechanical tests conducted successfully demonstrated that the low-cost conductive coating can be used to actively alter the stiffness of the structure through surface joule heating. The process was found to result in repeatable and reproduceable stiffness tuning. Stiffness reductions of 56% and 94% were demonstrated for single and dual material configurations under the same electrical loading. The proposed methodology can be implemented to actively control the properties of polymeric lattice materials/structures where the change in the composition of polymers (introduce bulk electrical conductivity) is difficult and can have a wide range of applications in soft robotics, shape-changing, and deployable structures.
Harmonic generation in a terawatt x-ray free-electron laser
Authors: Freund H P , O’Shea P G 
Published: April 2024

Abstract
Terawatt x-ray free-electron lasers (XFELs) represent the frontier in further development of x-ray sources and require high current densities with strong transverse focusing. In this paper, we investigate the implications/potentialities of TW XFELs on the generation of harmonics at still shorter wavelengths and higher photon energies. The simulations indicate that significant power levels are possible at high harmonics of the XFEL resonance and that these XFELs can be an important coherent source of hard x-rays through the gamma ray spectrum. For this purpose, we use the MINERVA simulation code which self-consistently includes harmonic generation. Both helical and planar undulators are discussed in which the fundamental is at 1.5 Å and study the associated harmonic generation. While tapered undulators are needed to reach TW powers at the fundamental, the taper does not enhance the harmonics because the taper must start before saturation of the fundamental, while the harmonics saturate before this point is reached. Nevertheless, the harmonics reach substantial powers. Simulations indicate that, for the parameters under consideration, peak powers of the order of 180 MW are possible at the fifth harmonic with a photon energy of about 41 keV and still high harmonics may also be generated at substantial powers. Such high harmonic powers are certain to enable a host of enhanced applications.
Multiple rogue wave solutions of the (1+1)-dimensional Benjamin-Ono equation
Authors: Ma Wenbo , Sudao Bilige , Shao Hangbing 
Published: April 2024

Abstract
In this paper, by means of symbolic computation, we studied the multiple rogue wave (multi-RW) solutions of the (1+1)-dimensional Benjamin-Ono (BO) equation, which is used to describe one-dimensional deep water internal waves in mathematics. In order to achieve this goal, we used the bilinear neural network method to construct the superposition formulas of n-RW based on the bilinear form. Here we only showed 1-RW, 3-RW, and 6-RW solutions. The influence of the parameters in the solution expression upon the characteristics related to RW also was discussed. Then, the dynamics characteristics of the multi-RW solutions were analyzed by drawing the three-dimensional plot, contour plot, and density plot. We observed that m-RW consisted of m independent 1-RW. This interesting phenomenon helped us to better reveal the evolution mechanism of the (1+1)-dimensional BO equation.
First-principles exploration of N- and Pd-doped graphene as CO and NO2 gas sensor for operation status evaluation in AIS
Authors: Wu Hailong , Zhong Shan , He Dan , Cui Hao 
Published: April 2024

Abstract
To evaluate the operation status of air insulated switchgears (AIS), this work purposes N- and Pd- embedded graphene (N- and Pd-graphene) as potential gas sensors upon two typical faults gases (CO and NO2) from the first-principles simulations. It is found that the N and Pd atoms can be stably trapped on the C-vacancy of the C-defected graphene with the formation energy of −12.17 and −5.12 eV, respectively. N-graphene behaves physisorption towards CO and NO2 molecules while Pd-graphene behaves chemisorption instead. The resistance-type and work function (WF)-based sensing mechanisms of N- and Pd-graphene upon such two gas species are illustrated and uncovered by analyzing their deformations of electronic property and WF in the gas adsorption systems, which reveals the potential of Pd-graphene as a resistive CO and NO2 sensor, N-graphene as a resistive NO2 sensor, as well as the N- and Pd-graphene as WF-based gas sensor for NO2 detection. This work highlights the comparison of adsorption and sensing performances between N- and Pd-graphene upon two typical gas sensors in AIS, which would be meaningful to explore novel graphene-based sensing materials facilitating their investigations and applications in the power system.
Review of Hubble tension solutions with new SH0ES and SPT-3G data
Authors: Khalife Ali Rida , Zanjani Maryam Bahrami , Galli Silvia , Günther Sven , Lesgourgues Julien , Benabed Karim 
Published: April 2024

Abstract
We present an updated analysis of eleven cosmological models that may help reduce the Hubble tension, which now reaches the 6σ level when considering the latest SH0ES measurement versus recent CMB and BAO data, assuming ΛCDM.
Specifically, we look at five classical extensions of ΛCDM (with massive neutrinos, spatial curvature, free-streaming or self-interacting relativistic relics, or dynamical dark energy) and six elaborate models featuring either a time-varying electron mass, early dark energy or some non-trivial interactions in the neutrino sector triggered by a light Majoron. We improve over previous works in several ways. We include the latest data from the South Pole Telescope as well as the most recent measurement of the Hubble rate by the SH0ES collaboration. We treat the summed neutrino mass as a free parameter in most of our models, which reveals interesting degeneracies and constraints. We define additional metrics to assess the potential of a model to reduce or even solve the Hubble tension. We validate an emulator that uses active learning to train itself during each parameter inference run for any arbitrary model. We find that the time-varying electron mass and the Majoron models are now ruled out at more than 3σ. Models with a time-varying electron mass and spatial curvature or with early dark energy reduce the tension to 1.0-2.9σ. Nevertheless, none of the models considered in this work is favored with enough statistical significance to become the next concordance model of Cosmology.
Constraints on Lorentz invariance violation from the LHAASO observation of GRB 221009A
Authors: Yang Yu-Ming , Bi Xiao-Jun , Yin Peng-Fei 
Published: April 2024

Abstract
In some quantum gravity (QG) theories, Lorentz symmetry may be broken above the Planck scale. The Lorentz invariance violation (LIV) may induce observable effects at low energies and be detected at high energy astrophysical measurements.
The Large High Altitude Air Shower Observatory (LHAASO) has detected the onset, rise, and decay phases of the afterglow of GRB 221009A, covering a wide energy range of photons approximately from 0.2 to 13 TeV. This observation provides an excellent opportunity to study the Lorentz invariance violation effect. In this study, we simultaneously utilize the data from the KM2A and WCDA detectors of LHAASO, and apply two event by event methods, namely the pair view method and maximum likelihood method, to investigate LIV. We obtain stringent constraints on the QG energy scale. For instance, through the maximum likelihood method, we determine the 95% confidence level lower limits to be E
QG,1 > 14.7 (6.5) × 1019 GeV for the subluminal (superluminal) scenario of n = 1, and E
QG,2 > 12.0 (7.2) × 1011 GeV for the subluminal (superluminal) scenario of n = 2. We find that the rapid rise and slow decay behaviors of the afterglow can impose strong constraints on the subluminal scenario, while the constraints are weaker for the superluminal scenario.
In-flight Energy Calibration of the GECAM Gamma-ray Detectors
Authors: Qiao Rui , Guo Dong-Ya , Peng Wen-Xi , Zhang Yan-Qiu , Xiao Shuo , Xiong Shao-Lin , Zheng Chao , Li Chao-Yang , Liu Jia-Cong , Xue Wang-Chen , He Jian-Jian , An Zheng-Hua , Zhang Da-Li , Li Xin-Qiao , Song Li-Ming , Zheng Shi-Jie , Gong Ke , Liu Ya-Qing , Song Xin-Ying , Zhao Xiao-Yun , Wen Xiang-Yang , Xu Yan-Bing , Ma Xiang , Li Xiao-Bo , Wang Ping , Huang Yue , Cai Ce , Yi Qi-Bin , Zhao Yi , Wang Chen-Wei 
Published: April 2024

Abstract
The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission is designed to monitor the Gamma-Ray Bursts (GRBs) associated with gravitational waves and other high-energy transient sources. The mission consists of two microsatellites which are planned to operate at the opposite sides of the Earth. Each GECAM satellite could detect and localize GRBs in about 8 keV–5 MeV with its 25 Gamma-Ray Detectors (GRDs). In this work, we report the in-flight energy calibration of GRDs using the characteristic gamma-ray lines in the background spectra, and show their performance evolution during the commissioning phase. Besides, a preliminary cross-calibration of energy response with Fermi GBM data is also presented, validating the energy response of GRDs.
An SSVEP-based BCI with 112 targets using frequency spatial multiplexing
Authors: Liu Yaru , Dai Wei , Liu Yadong , Hu Dewen , Yang Banghua , Zhou Zongtan 
Published: April 2024

Abstract

Objective. Brain–computer interface (BCI) systems with large directly accessible instruction sets are one of the difficulties in BCI research. Research to achieve high target resolution (

⩾

100) has not yet entered a rapid development stage, which contradicts the application requirements. Steady-state visual evoked potential (SSVEP) based BCIs have an advantage in terms of the number of targets, but the competitive mechanism between the target stimulus and its neighboring stimuli is a key challenge that prevents the target resolution from being improved significantly. Approach. In this paper, we reverse the competitive mechanism and propose a frequency spatial multiplexing method to produce more targets with limited frequencies. In the proposed paradigm, we replicated each flicker stimulus as a 2 × 2 matrix and arrange the matrices of all frequencies in a tiled fashion to form the interaction interface. With different arrangements, we designed and tested three example paradigms with different layouts. Further we designed a graph neural network that distinguishes between targets of the same frequency by recognizing the different electroencephalography (EEG) response distribution patterns evoked by each target and its neighboring targets. Main results. Extensive experiment studies employing eleven subjects have been performed to verify the validity of the proposed method. The average classification accuracies in the offline validation experiments for the three paradigms are 89.16%, 91.38%, and 87.90%, with information transfer rates (ITR) of 51.66, 53.96, and 50.55 bits/min, respectively. Significance. This study utilized the positional relationship between stimuli and did not circumvent the competing response problem. Therefore, other state-of-the-art methods focusing on enhancing the efficiency of SSVEP detection can be used as a basis for the present method to achieve very promising improvements.
Climate change critically affects the status of the land-system change planetary boundary
Authors: Tobian Arne , Gerten Dieter , Fetzer Ingo , Schaphoff Sibyll , Andersen Lauren Seaby , Cornell Sarah , Rockström Johan 
Published: April 2024

Abstract
The planetary boundaries framework defines a safe operating space for humanity. To date, these boundaries have mostly been investigated separately, and it is unclear whether breaching one boundary can lead to the transgression of another. By employing a dynamic global vegetation model, we systematically simulate the strength and direction of the effects of different transgression levels of the climate change boundary (using climate output from ten phase 6 of the Coupled Model Intercomparison Project models for CO2 levels ranging from 350 ppm to 1000 ppm). We focus on climate change-induced shifts of Earth’s major forest biomes, the control variable for the land-system change boundary, both by the end of this century and, to account for the long-term legacy effect, by the end of the millennium. Our simulations show that while staying within the 350 ppm climate change boundary co-stabilizes the land-system change boundary, breaching it (>450 ppm) leads to critical transgression of the latter, with greater severity the higher the ppm level rises and the more time passes. Specifically, this involves a poleward treeline shift, boreal forest dieback (nearly completely within its current area under extreme climate scenarios), competitive expansion of temperate forest into today’s boreal zone, and a slight tropical forest extension. These interacting changes also affect other planetary boundaries (freshwater change and biosphere integrity) and provide feedback to the climate change boundary itself. Our quantitative process-based study highlights the need for interactions to be studied for a systemic operationalization of the planetary boundaries framework.
Optimal superdense coding capacity in the non-Markovian regime
Authors: Aiache Y , Al-Kuwari S , El Anouz K , El Allati A 
Published: April 2024

Abstract
Superdense coding (SDC) is a significant technique widely used in quantum information processing. Indeed, it consists of sending two bits of classical information using a single qubit, leading to faster and more efficient quantum communication. In this paper, we propose a model to evaluate the effect of backflow information in a SDC protocol through a non-Markovian dynamics. The model considers a qubit interacting with a structured Markovian environment. In order to generate a non-Markovian dynamic, an auxiliary qubit contacts a Markovian reservoir in such a way that the non-Markovian regime can be induced. By varying the coupling strength between the central qubit and the auxiliary qubit, the two dynamical regimes can be switched interchangeably. An enhancement in non-Markovian effects corresponds to an increase in this coupling strength. Furthermore, we conduct an examination of various parameters, namely temperature weight, and decoherence parameters in order to explore the behaviors of SDC, quantum fisher information (QFI), and local quantum uncertainty using an exact calculation. The obtained results show a significant relationship between non-classical correlations and QFI since they behave similarly, allowing them to detect what is beyond entanglement. In addition, the presence of non-classical correlations enables us to detect the optimal SDC capacity in a non-Markovian regime.
Polar duality and the reconstruction of quantum covariance matrices from partial data
Authors: de Gosson Maurice 
Published: April 2024

Abstract
We address the problem of the reconstruction of quantum covariance matrices using the notion of Lagrangian and symplectic polar duality introduced in previous work. We apply our constructions to Gaussian quantum states which leads to a non-trivial generalization of Pauli’s reconstruction problem and we state a simple tomographic characterization of such states.
Pressure of Coulomb systems with volume-dependent long-range potentials
Authors: Onegin A S , Demyanov G S , Levashov P R 
Published: April 2024

Abstract
In this work, we consider the pressure of Coulomb systems, in which particles interact via a volume-dependent potential (in particular, the Ewald potential and its angular-averaged version (Demyanov and Levashov 2022 J. Phys. A: Math. Theor.
55 385202)). We confirm that the expression for the virial pressure should be corrected in this case. We show that the corrected virial pressure coincides with the formula obtained by differentiation of free energy if the potential energy is a homogeneous function of particle coordinates and a cell length. As a consequence, we find out that the expression for the pressure in the recent paper by Liang et al (2022 J. Chem. Phys.
157 144102) is incorrect.
A hybrid quantum ensemble learning model for malicious code detection
Authors: Xiong Qibing , Ding Xiaodong , Fei Yangyang , Zhou Xin , Du Qiming , Feng Congcong , Shan Zheng 
Published: April 2024

Abstract
Quantum computing as a new computing model with parallel computing capability and high information carrying capacity, has attracted a lot of attention from researchers. Ensemble learning is an effective strategy often used in machine learning to improve the performance of weak classifiers. Currently, the classification performance of quantum classifiers is not satisfactory enough due to factors such as the depth of quantum circuit, quantum noise, and quantum coding method, etc. For this reason, this paper combined the ensemble learning idea and quantum classifiers to design a novel hybrid quantum machine learning model. Firstly, we run the Stacking method in classical machine learning to realize the dimensionality reduction of high-latitude data while ensuring the validity of data features. Secondly, we used the Bagging method and Bayesian hyperparameter optimization method applied to quantum support vector machine (QSVM), quantum K nearest neighbors (QKNN), variational quantum classifier (VQC). Thirdly, the voting method is used to ensemble the predict results of QSVM, QKNN, VQC as the final result. We applied the hybrid quantum ensemble machine learning model to malicious code detection. The experimental results show that the classification precision (accuracy, F1-score) of this model has been improved to 98.9% (94.5%, 94.24%). Combined with the acceleration of quantum computing and the higher precision rate, it can effectively deal with the growing trend of malicious codes, which is of great significance to cyberspace security.
Strichartz type estimates for solutions to the Schrödinger equation
Authors: Chen Jie 
Published: April 2024

In this article, we show the necessary and sufficient conditions for the inequality

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\begin{equation*} \|u\|_{L_t^qL_x^r}\lesssim \|u\|_{X^{s,b}}, \end{equation*}

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. These estimates are also referred to as Strichartz estimates related to Schrödinger equation. We also give a new proof of the maximal function estimates for solutions to Schrödinger and Airy equations.
Confounder-dependent Bayesian mixture model: Characterizing heterogeneity of causal effects in air pollution epidemiology
Authors: Zorzetto Dafne , Bargagli-Stoffi Falco J , Canale Antonio , Dominici. Francesca 
Published: April 2024

ABSTRACT
Several epidemiological studies have provided evidence that long-term exposure to fine particulate matter (pm2.5) increases mortality rate. Furthermore, some population characteristics (e.g., age, race, and socioeconomic status) might play a crucial role in understanding vulnerability to air pollution. To inform policy, it is necessary to identify groups of the population that are more or less vulnerable to air pollution. In causal inference literature, the group average treatment effect (GATE) is a distinctive facet of the conditional average treatment effect. This widely employed metric serves to characterize the heterogeneity of a treatment effect based on some population characteristics. In this paper, we introduce a novel Confounder-Dependent Bayesian Mixture Model (CDBMM) to characterize causal effect heterogeneity. More specifically, our method leverages the flexibility of the dependent Dirichlet process to model the distribution of the potential outcomes conditionally to the covariates and the treatment levels, thus enabling us to: (i) identify heterogeneous and mutually exclusive population groups defined by similar GATEs in a data-driven way, and (ii) estimate and characterize the causal effects within each of the identified groups. Through simulations, we demonstrate the effectiveness of our method in uncovering key insights about treatment effects heterogeneity. We apply our method to claims data from Medicare enrollees in Texas. We found six mutually exclusive groups where the causal effects of pm2.5 on mortality rate are heterogeneous.
A semiparametric Gaussian mixture model for chest CT-based 3D blood vessel reconstruction
Authors: Zeng Qianhan , Zhou Jing , Ji Ying , Wang Hansheng 
Published: April 2024

Summary
Computed tomography (CT) has been a powerful diagnostic tool since its emergence in the 1970s. Using CT data, 3D structures of human internal organs and tissues, such as blood vessels, can be reconstructed using professional software. This 3D reconstruction is crucial for surgical operations and can serve as a vivid medical teaching example. However, traditional 3D reconstruction heavily relies on manual operations, which are time-consuming, subjective, and require substantial experience. To address this problem, we develop a novel semiparametric Gaussian mixture model tailored for the 3D reconstruction of blood vessels. This model extends the classical Gaussian mixture model by enabling nonparametric variations in the component-wise parameters of interest according to voxel positions. We develop a kernel-based expectation–maximization algorithm for estimating the model parameters, accompanied by a supporting asymptotic theory. Furthermore, we propose a novel regression method for optimal bandwidth selection. Compared to the conventional cross-validation-based (CV) method, the regression method outperforms the CV method in terms of computational and statistical efficiency. In application, this methodology facilitates the fully automated reconstruction of 3D blood vessel structures with remarkable accuracy.
Nitrogen-fixing bacterial communities differ between perennial agroecosystem crops
Authors: Sorochkina Kira , Martens-Habbena Willm , Reardon Catherine L , Inglett Patrick W , Strauss Sarah L 
Published: April 2024

Abstract
Biocrusts, common in natural ecosystems, are specific assemblages of microorganisms at or on the soil surface with associated microorganisms extending into the top centimeter of soil. Agroecosystem biocrusts have similar rates of nitrogen (N) fixation as those in natural ecosystems, but it is unclear how agricultural management influences their composition and function. This study examined the total bacterial and diazotrophic communities of biocrusts in a citrus orchard and a vineyard that shared a similar climate and soil type but differed in management. To contrast climate and soil type, these biocrusts were also compared with those from an apple orchard. Unlike natural ecosystem biocrusts, these agroecosystem biocrusts were dominated by proteobacteria and had a lower abundance of cyanobacteria. All of the examined agroecosystem biocrust diazotroph communities were dominated by N-fixing cyanobacteria from the Nostocales order, similar to natural ecosystem cyanobacterial biocrusts. Lower irrigation and fertilizer in the vineyard compared with the citrus orchard could have contributed to biocrust microbial composition, whereas soil type and climate could have differentiated the apple orchard biocrust. Season did not influence the bacterial and diazotrophic community composition of any of these agroecosystem biocrusts. Overall, agricultural management and climatic and edaphic factors potentially influenced the community composition and function of these biocrusts.