bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fermi acceleration under Lorentz invariance violation
Authors: Duarte Matheus , de Souza Vitor 
Published: October 2024

Abstract
In this paper, the acceleration of particles in astrophysical sources by the Fermi mechanism is revisited under the assumption of Lorentz invariance violation (LIV). We calculate the energy spectrum and the acceleration time of particles leaving the source as a function of the energy beyond which the Lorentz invariance violation becomes relevant. Lorentz invariance violation causes significant changes in the acceleration of particles by the first and second-order Fermi mechanisms. The energy spectrum of particles accelerated by first-order Fermi mechanism under LIV assumption shows a strong suppression for energies above the break. The calculations presented here complete the scenario for LIV searches with astroparticles by showing, for the first time, how the benchmark acceleration mechanisms (Fermi) are modified under LIV assumption.
A test of MOND and emergent gravity with SMACS J0723.3-7327 using eROSITA observations
Authors: Govind Ambica , Desai Shantanu 
Published: October 2024

Abstract
We implement a test of MOND and Verlinde's Emergent Gravity using the galaxy cluster SMACS J0723-7327, which has been recently imaged using the eROSITA X-ray telescope as well as with JWST. We test MOND using two independent methods. The first method involves comparing the dynamical MOND mass and baryonic mass, while the second method entails a comparison of the MOND-estimated temperature with the observed temperature. We then compare the unseen mass predicted by Emergent Gravity with the estimated dark matter mass. We find that MOND shows a mass discrepancy in the central regions at high significance levels. The observed temperature profile is in marginal disagreement with that in the MOND paradigm. However, the Emergent Gravity Theory agrees in accurately accounting for the dynamical mass in the inner regions within 1σ. Our results are qualitatively consistent with the earlier tests on other clusters.
Reconstructing patchy helium reionization using the cosmic microwave background and large-scale structure
Authors: Çalışkan Mesut , Anil Kumar Neha , Hotinli Selim C. , Kamionkowski Marc 
Published: October 2024

Abstract
The intergalactic helium became fully ionized by the end of cosmic noon (z ∼ 2).
Similarly to the reionization of hydrogen, helium reionization is expected to be patchy, driven by luminous quasars that ionize the intergalactic gas in their surrounding environment.
Probing the morphology of ionized electrons during this epoch can provide crucial information about early structure formation, including the clustering and luminosities of quasars, the accretion rates, variability, and lifetimes of active galactic nuclei, as well as the growth and evolution of supermassive black holes.
In this study, we present how measurements of the cosmic microwave background (CMB) can be used to reconstruct the optical-depth fluctuations resulting from patchy helium reionization.
As helium reionization occurred at lower redshifts, upcoming probes of large-scale structure surveys will present a significant opportunity to enhance the prospects of probing this epoch by their combined analysis with the CMB.
Using a joint information-matrix analysis of hydrogen and helium reionization, we show that near-future galaxy and CMB surveys will have enough statistical power to detect optical-depth fluctuations due to doubly-ionized helium, providing a way of measuring the redshift and duration of helium reionization to high significance.
We also show that modeling uncertainties in helium reionization can impact the measurement precision of parameters characterizing hydrogen reionization.
Dark solitons on elliptic function background for the defocusing Hirota equation
Authors: Wang Xin , He Jingsong 
Published: October 2024

Abstract
We investigate dark solitons lying on elliptic function background in the defocusing Hirota equation with third-order dispersion and self-steepening terms. By means of the modified squared wavefunction method, we obtain the Jacobi’s elliptic solution of the defocusing Hirota equation, and solve the related linear matrix eigenvalue problem on elliptic function background. The elliptic N-dark soliton solution in terms of theta functions is constructed by the Darboux transformation and limit technique. The asymptotic dynamical behaviors for the elliptic N-dark soliton solution as t → ± ∞ are studied. Through numerical plots of the elliptic one-, two- and three-dark solitons, the amplification effect on the velocity of elliptic dark solitons, and the compression effect on the soliton spatiotemporal distributions produced by the third-order dispersion and self-steepening terms are discussed.
Capture behavior of self-propelled particles into a hexatic ordering obstacle
Authors: Li 李 Jing-Yi 静怡 , Shi 石 Jin-Lei 金蕾 , Wang 王 Ying-Ying 英英 , Pan 潘 Jun-Xing 俊星 , Zhang 张 Jin-Jun 进军 
Published: October 2024

Abstract
Computer simulations are utilized to investigate the dynamic behavior of self-propelled particles (SPPs) within a complex obstacle environment. The findings reveal that SPPs exhibit three distinct aggregation states within the obstacle, each contingent on specific conditions. A phase diagram outlining the aggregation states concerning self-propulsion conditions is presented. The results illustrate a transition of SPPs from a dispersion state to a transition state as persistence time increases within the obstacle. Conversely, as the driving strength increases, self-propelled particles shift towards a cluster state. A systematic exploration of the interplay between driving strength, persistence time, and matching degree on the dynamic behavior of self-propelled particles is conducted. Furthermore, an analysis is performed on the spatial distribution of SPPs along the y-axis, capture rate, maximum capture probability, and mean-square displacement. The insights gained from this research make valuable contributions to understanding the capture and collection of active particles.
Correlation of microstructure and magnetic softness of Si-microalloying FeNiBCuSi nanocrystalline alloy revealed by nanoindentation
Authors: Wang 汪 Benjun 本军 , Liu 刘 Wenjun 文君 , Liu 刘 Li 莉 , Wang 王 Yu 玉 , Hang 杭 Yu 宇 , Wang 王 Xinyu 新宇 , Shi 施 Mengen 蒙恩 , Feng 冯 Hanchen 汉臣 , Hou 侯 Long 龙 , Yuan 袁 Chenchen 晨晨 , Li 李 Zhong 忠 , Li 李 Weihuo 维火 
Published: October 2024

Abstract
Compared to the commercial soft-magnetic alloys, the high saturation magnetic flux density (B
s) and low coercivity (H
c) of post-developed novel nanocrystalline alloys tend to realize the miniaturization and lightweight of electronic products, thus attracting great attention. In this work, we designed a new FeNiBCuSi formulation with a novel atomic ratio, and the microstructure evolution and magnetic softness were investigated. Microstructure analysis revealed that the amount of Si prompted the differential chemical fluctuations of Cu element, favoring the different nucleation and growth processes of α-Fe nanocrystals. Furthermore, microstructural defects associated with chemical heterogeneities were unveiled using the Maxwell–Voigt model with two Kelvin units and one Maxwell unit based on creeping analysis by nanoindentation. The defect, with a long relaxation time in relaxation spectra, was more likely to induce the formation of crystal nuclei that ultimately evolved into the α-Fe nanocrystals. As a result, Fe84Ni2B12.5Cu1Si0.5 alloy with refined uniform nanocrystalline microstructure exhibited excellent magnetic softness, including a high B
s of 1.79 T and very low H
c of 2.8 A/m. Our finding offers new insight into the influence of activated defects associated with chemical heterogeneities on the microstructures of nanocrystalline alloy with excellent magnetic softness.
Upconversion photoluminescence of Er-doped Bi4Ti3O12 ceramics enhanced by vacancy clusters revealed by positron annihilation spectroscopy
Authors: Cheng 程 Huiru 慧茹 , Li 李 Yuhuan 钰环 , Pan 潘 Ziwen 子文 , Liu 刘 Jiandang 建党 , Ye 叶 Bangjiao 邦角 
Published: October 2024

Abstract
Doping of rare earth elements into Bi4Ti3O12 can significantly enhance the upconversion photoluminescence (UCPL) properties, but its structure–property relationship is still unclear. In this work, Er-doped bismuth titanate Bi4−x
Er
x
Ti3O12 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics were synthesized via solid-state reaction method. The x-ray diffraction analysis confirmed the orthorhombic crystalline structure of the Bi4−x
Er
x
Ti3O12 ceramics without any secondary phases. Experiments and calculations of positron annihilation spectroscopy were carried out to characterize their defect structure. The comparison between the experimental and calculated lifetime revealed that vacancy clusters were the main defects in the ceramics. The increase of the intensity of the second positron lifetime component (I
2) of Bi3.5Er0.5Ti3O12 ceramics indicated the presence of a high concentration of vacancy clusters. The UCPL spectra showed the sudden enhanced UCPL performance in Bi3.7Er0.3Ti3O12 and Bi3.5Er0.5Ti3O12 ceramics, which were consistent with the variation of the second positron lifetime component (I
2). These results indicate that the enhanced UCPL properties are influenced not only by the concentrations of rare earth ions but also by the concentration of vacancy clusters present within the ceramics.
Molecular beam epitaxial growth and physical properties of AlN/GaN superlattices with an average 50% Al composition
Authors: Li 李 Siqi 思琦 , Shao 邵 Pengfei 鹏飞 , Liang 梁 Xiao 潇 , Chen 陈 Songlin 松林 , Li 李 Zhenhua 振华 , Su 苏 Xujun 旭军 , Tao 陶 Tao 涛 , Xie 谢 Zili 自力 , Liu 刘 Bin 斌 , Ajmal Khan M. , Wang Li , Lin T. T. , Hirayama Hideki , Zhang 张 Rong 荣 , Wang 王 Ke 科 
Published: October 2024

Abstract
We report molecular beam epitaxial growth and electrical and ultraviolet light emitting properties of (AlN)m/(GaN)n superlattices (SLs), where m and n represent the numbers of monolayers. Clear satellite peaks observed in XRD 2θ–ω scans and TEM images evidence the formation of clear periodicity and atomically sharp interfaces. For (AlN)m/(GaN)n SLs with an average Al composition of 50%, we have obtained an electron density up to 4.48 × 1019 cm−3 and a resistivity of 0.002 Ω⋅cm, and a hole density of 1.83 × 1018 cm−3 with a resistivity of 3.722 Ω⋅cm, both at room temperature. Furthermore, the (AlN)m/(GaN)n SLs exhibit a blue shift for their photoluminescence peaks, from 403 nm to 318 nm as GaN is reduced from n = 11 to n = 4 MLs, reaching the challenging UVB wavelength range. The results demonstrate that the (AlN)m/(GaN)n SLs have the potential to enhance the conductivity and avoid the usual random alloy scattering of the high-Al-composition ternary AlGaN, making them promising functional components in both UVB emitter and AlGaN channel high electron mobility transistor applications.
Nonlinear enhanced mass sensor based on optomechanical system
Authors: Man 满 Xin-Xin 鑫鑫 , Sun 孙 Jing 静 , Zhang 张 Wen-Zhao 闻钊 , Luo 罗 Lijuan 丽娟 , Jin 金 Guangri 光日 
Published: October 2024

Abstract
A high-precision and tunable mass detection scheme based on a double-oscillator optomechanical system is proposed. By designating one of the oscillators as the detection port, tiny mass signals can be probed through the frequency shift of the output spectrum, utilizing the system’s optomechanically induced transparency (OMIT) effect. By solving the output of the optical mode, we demonstrate that the system exhibits two OMIT windows due to the double-oscillator coupling, with one window being strongly dependent on the mass to be detected. Characterizing the spectrum around this window enables high magnification and precise detection of the input signal under nonlinear parameter conditions. Additionally, our scheme shows resilience to environmental temperature variations and drive strength perturbations.
Apparatus for producing single strontium atoms in an optical tweezer array
Authors: Wen 文 Kai 凯 , Chen 陈 Huijin 辉锦 , Yan 颜 Xu 煦 , Ren 任 Zejian 泽剑 , He 何 Chengdong 成东 , Hajiyev Elnur , Fung Wong 黄 Preston Tsz 梓峰 , Jo Gyu-Boong 
Published: October 2024

Abstract
We outline an experimental setup for efficiently preparing a tweezer array of 88Sr atoms. Our setup uses permanent magnets to maintain a steady-state two-dimensional magneto-optical trap (MOT) which results in a loading rate of up to 108 s−1 at 5 mK for the three-dimensional blue MOT. This enables us to trap 2 × 106
88Sr atoms at 2 μK in a narrow-line red MOT with the 1S0 → 3P1 intercombination transition at 689 nm. With the Sisyphus cooling and pairwise loss processes, single atoms are trapped and imaged in 813 nm optical tweezers, exhibiting a lifetime of 2.5 min. We further investigate the survival fraction of a single atom in the tweezers and characterize the optical tweezer array using a release and recapture technique. Our experimental setup serves as an excellent reference for those engaged in experiments involving optical tweezer arrays, cold atom systems, and similar research.
Global motor dynamics - Invariant neural representations of motor behavior in distributed brain-wide recordings
Authors: Ottenhoff Maarten C , Verwoert Maxime , Goulis Sophocles , Wagner Louis , van Dijk Johannes P , Kubben Pieter L , Herff Christian 
Published: October 2024

Abstract

Objective

. Motor-related neural activity is more widespread than previously thought, as pervasive brain-wide neural correlates of motor behavior have been reported in various animal species. Brain-wide movement-related neural activity have been observed in individual brain areas in humans as well, but it is unknown to what extent global patterns exist.
Approach.
Here, we use a decoding approach to capture and characterize brain-wide neural correlates of movement. We recorded invasive electrophysiological data from stereotactic electroencephalographic electrodes implanted in eight epilepsy patients who performed both an executed and imagined grasping task. Combined, these electrodes cover the whole brain, including deeper structures such as the hippocampus, insula and basal ganglia. We extract a low-dimensional representation and classify movement from rest trials using a Riemannian decoder.
Main results

. We reveal global neural dynamics that are predictive across tasks and participants. Using an ablation analysis, we demonstrate that these dynamics remain remarkably stable under loss of information. Similarly, the dynamics remain stable across participants, as we were able to predict movement across participants using transfer learning.
Significance

. Our results show that decodable global motor-related neural dynamics exist within a low-dimensional space. The dynamics are predictive of movement, nearly brain-wide and present in all our participants. The results broaden the scope to brain-wide investigations, and may allow combining datasets of multiple participants with varying electrode locations or calibrationless neural decoder.
Polylysine in biomedical applications: from composites to breakthroughs
Authors: Deepak A , Hilaj Erina , Singh Manisha , Manjunath C , Rayshan Ahmed Raheem , Sharma Manish , Nainwal Pankaj , Kumar Ambati Vijay , Choudhary Alka N 
Published: October 2024

Abstract
Polylysine-based composites have emerged as promising materials in biomedical applications due to their versatility, biocompatibility, and tunable properties. In drug delivery, polylysine-based composites furnish a novel platform for targeted and controlled release of therapeutic agents. Their high loading capacity and capability to encapsulate diverse drugs make them ideal candidates for addressing challenges such as drug stability and controlled release kinetics. Additionally, their biocompatibility ensures minimal cytotoxicity, which is vital for biomedical applications. They also hold substantial potential in tissue engineering by providing a scaffold with tunable mechanical characteristics and surface properties and can support cell adhesion, proliferation, and differentiation. Furthermore, their bioactive nature facilitates cellular interactions, promoting tissue regeneration and integration. Wound healing is another area where polylysine-based composites show promise. Their antimicrobial properties help prevent infections, while their ability to foster cell migration and proliferation accelerates the wound healing procedure. Incorporation of growth factors or other bioactive molecules further enhances their therapeutic effectiveness. In biosensing applications, they serve as robust substrates for immobilizing biomolecules and sensing elements. Their high surface area-to-volume ratio and excellent biocompatibility improve sensor sensitivity and selectivity, enabling accurate detection of biomarkers or analytes in biological samples. Polylysine-based composites offer potential as contrast agents in bioimaging, aiding in the diagnosis and monitoring of diseases. Overall, polylysine-based composites represent a versatile platform with diverse applications in biomedical research and clinical practice, holding great promise for addressing various healthcare challenges.
Estimating transpiration globally by integrating the Priestley-Taylor model with neural networks
Authors: Hannemann Marco , García-García Almudena , Poyatos Rafael , Mahecha Miguel D , Peng Jian 
Published: October 2024

Abstract
Transpiration (T), the component of evapotranspiration (ET) controlled by the vegetation, dominates terrestrial ET in many ecosystems; however, estimating it accurately, especially at the global scale, remains a considerable challenge. Existing approaches mostly rely on the relationship between T and photosynthesis, but untangling this relationship is difficult and leads to diverging T estimates. Limited in-situ measurements and the inability to directly measure transpiration from space further complicate the reliable assessment of this crucial process in the terrestrial water cycle. Here, we developed a new hybrid Priestley–Taylor (PT) model combined with an Artificial Neural Network (ANN) using globally available remote sensing and reanalysis data of soil moisture, vapor pressure deficit and windspeed. We also take advantage of the newly released global sap flow measurement network SAPFLUXNET. In the proposed approach, we avoid the parameterization of stomatal conductance by training the ANN on the PT-Coefficient α, obtained by inverting the PT equation. The results showed that our model framework can estimate T in different forest ecosystems based on few predictors. By utilizing forcings from independent datasets, we eliminate the reliance on in-situ measurements for predicting T. Through upscaling actual observations to a larger scale, this model framework helps alleviate the scarcity of T products. Intercomparison of T with ET partitioning methods based on eddy covariance data, shows high performances (KGE of 0.69 in Europe and 0.60 in North America), slightly improving estimates compared to other models. Analysis of contribution of T to ET across 100 FLUXNET sites result in a global mean of 55.2%. We believe that modelling T independent from the carbon cycle can support our understanding of land-atmosphere feedbacks and climate extremes in future research.
Seasonal variability in the global relevance of mountains to satisfy lowland water demand
Authors: Hanus Sarah , Burek Peter , Smilovic Mikhail , Seibert Jan , Viviroli Daniel 
Published: October 2024

Abstract
Mountain areas play a vital role in global water resources as they often generate disproportionally high runoff and seasonally delay runoff due to storage as snow and ice. Water originating from mountains is used to satisfy human water demand further downstream in the lowlands of the corresponding river basins. Although the relevance of mountains for water supply is widely acknowledged, our current quantitative knowledge of their relevance for human water use on a global scale remains limited to decadal averages. As both water demand and mountain water supply have a strong seasonality, it is crucial to assess the global relevance of mountain areas beyond the annual time scale. To this end, we examined the share of lowland surface water abstraction (LSWA) stemming from mountain runoff in all river basins larger than 10 000 km2 globally from 1990 to 2019, focusing on the intra-annual variability. We distinguished between essential runoff contributions from low and high mountains and potential mountain runoff contributions to LSWA. Essential mountain contributions are defined as the share of water abstractions in the lowlands that can solely be satisfied by mountain runoff, whereas potential mountain contributions are the share that can originate from the mountains but does not necessarily have to. Our results confirm a strong spatial heterogeneity in the contribution of mountain runoff to LSWA. Globally, 15% of annual LSWA can solely be satisfied by mountain runoff, with monthly variations between 9% and 23%, highlighting the strong seasonality in the reliance on mountain runoff for lowland water use. The share of potential mountain contributions is much higher (51% annually). Slightly less than half of the essential mountain contributions to LSWA are sourced from high mountains. This shows the disproportional relevance of these regions, constituting only around one-third of the total mountain area. Furthermore, our results show an increasing dependence of lowlands on mountain runoff contributions.
The distribution of environmental pressures from global dietary shift
Authors: DeCesaro Joseph M , Allison Edward H , Clawson Gage , Frazier Melanie , Gephart Jessica A , Hicks Christina C , Nash Kirsty L , Williams David R , Halpern Benjamin S 
Published: October 2024

Abstract
The production and consumption of food is one of the main drivers of environmental change globally. Meanwhile, many populations remain malnourished due to insufficient or unhealthy diets. Increasingly, dietary shifts are proposed as a means to address both environmental and health concerns. We have a limited understanding of how dietary shifts could alter where food is produced and consumed and how these changes would affect the distribution of environmental pressures both globally and across different groups of people. Here we combine new food flow data linking producing to consuming country with environmental pressures to estimate how a global shift to each of four diets (Indian, EAT-Lancet, Mediterranean, and mean Food Based Dietary Guidelines (FBDGs)) could affect environmental pressures at the global, country income group, and country level. Globally, cumulative pressures decrease under the Indian, EAT-Lancet, and Mediterranean scenarios and increase under FBDGs. On average, low income countries increase their cumulative consumption and production pressures while high income countries decrease their consumption pressures, and typically decrease their production pressures. Increases in low income countries are likely due to the nutritional inadequacy of current diets and the corresponding increases in consumption quantities with a shift to our diet scenarios. Despite these increases, we believe that three out four of our simulated dietary shifts can be seen as a net benefit by decreasing global pressures while low income countries increase pressures to adequately feed their populations. Additionally, considering principles of fairness applied, some nations are more responsible for causing historical environmental pressures and should shoulder more of the change. To facilitate more equitable shifts in global diets, resources, capacity, and knowledge sharing of sustainable agricultural practices are critical to minimize the increases in pressures that low income countries would incur to adequately feed their populations.