bluuebunny/crossref_metadata_2025 huggingface dataset:
Cascade adaptive optics with a second stage based on a Zernike wavefront sensor for exoplanet observations
Authors: N’Diaye M. , Vigan A. , Engler B. , Kasper M. , Dohlen K. , Leveratto S. , Floriot J. , Marcos M. , Bailet C. , Bristow P.
Published: November 2024

Context. Over the past decade, the high-contrast observation of disks and gas giant planets around nearby stars has been made possible with ground-based instruments using extreme adaptive optics (XAO). These facilities produce images with a Strehl ratio higher than 90% in the H band, in median observing conditions and high-flux regime. However, the correction leaves behind adaptive optics (AO) residuals, which impede studies of fainter or less massive exoplanets.

Aims. Cascade AO systems with a fast second stage based on a Pyramid wavefront sensor (PWFS) have recently emerged as an appealing solution to reduce the atmospheric wavefront errors. Since these phase aberrations are expected to be small, they can also be accurately measured by a Zernike wavefront sensor (ZWFS), a well-known concept for its high sensitivity and moderate linear capture range. We propose an alternative second stage that relies on the ZWFS to correct for the AO residuals.

Methods. We implemented the cascade AO with a ZWFS-based control loop on the ESO’s GPU-based High-order adaptive OpticS Testbench (GHOST) to validate the scheme in monochromatic light. We emulated the XAO first stage in different observing conditions (wind speed, seeing) and determined the corresponding operation parameters (e.g., number of controlled modes, integrator gain, loop calibration) that lead to stable loop operation and good correction performance. Our strategy was assessed in terms of corrected wavefront errors and contrast gain in the images with a Lyot coronagraph to probe its efficiency.

Results. In median wind speed and seeing, our second-stage AO with a ZWFS and a basic integrator was able to reduce the atmospheric residuals by a factor of 6 and increase the wavefront error stability with a gain of 2 between open and closed loop. In the presence of non-common path aberrations, we also achieved a contrast gain of a factor of 2 in the coronagraphic images at short separations from the source, proving the ability of our scheme to work in cascade with an XAO loop. In addition, it may prove useful for imaging fainter or lighter close-in companions. In more challenging conditions, contrast improvements are also achieved by adjusting the control loop features.

Conclusions. Our study validates the ZWFS-based second-stage AO loop as an effective solution to address small residuals left over from a single-stage XAO system for the coronagraphic observations of circumstellar environments. Our first in-lab demonstration paves the way for more advanced versions of our approach with different temporal control laws, non-linear reconstructors, and spectral widths. This would allow our approach to operate in high-contrast facilities on the current 8–10 m class telescopes and Extremely Large Telescopes to observe exoplanets, all the way down to Earth analogs around M dwarfs.
A chemical link between saturated and unsaturated aldehydes and ketenes in the interstellar medium
Authors: Zasimov Pavel V. , Keresztes Barbara , Góbi Sándor , Volosatova Anastasia D. , Tarczay György
Published: November 2024

Context. Propenal (CH2CHCHO) and propanal (CH3CH2CHO) have been detected in various regions of the interstellar medium (ISM), from star-forming regions to a comet’s dusty coma. These molecules attract considerable attention due to their structural similarity to aldose sugars and their potential role in prebiotic astrochemistry. Their reactions with H atoms may significantly contribute to the chemical diversity in the ISM and link these molecules with each other and other isomers.

Aims. In this study, we aimed to investigate the astrophysically relevant low-temperature reactions of propenal and propanal molecules with H atoms to explore possible reaction pathways between these molecules and their isomers.

Methods. Propenal and propanal were isolated in solid para-H2 at 3.1 K. This medium, with its weak interactions, provides spec-troscopic data close to gas-phase values and allows for studying highly reactive short-lived species. Additionally, H atoms can be conveniently generated, they diffuse, and they react with the isolated molecules. The reactions were monitored using infrared (IR) spectroscopy. Quantum-chemical computations were employed to determine possible reaction paths and aid in spectral assignments.

Results. The reaction of CH2CHCHO and CH3CH2CHO with H atoms in the first step results in the production of CH2CH •CO/•CH2CHCO, CH3CH2•CO, and CH3•CHCHO radicals. Further H-atom reactions of CH3•CHCHO and R•CO radicals lead to the formation of methylketene (CH3CHCO) as the product of both the reaction of propenal and propanal. The two-step addition of H atoms to CH2CHCHO was found tentatively to produce CH3CH2CHO.

Conclusions. The radicals observed in the experiments are likely produced in dark molecular clouds on icy grains, increasing interstellar chemical complexity. The experiments suggest that H-atom reactions with propanal and propenal are important channels for methylketene production. The observed reactions imply that consecutive H-atom addition and H-atom abstraction reactions of propenal and propanal can catalyze interstellar H2 formation.
The PAU survey
Authors: Daza-Perilla I. V. , Eriksen M. , Navarro-Gironés D. , Gonzalez E. J. , Rodriguez F. , Gaztañaga E. , Baugh C. M. , Lares M. , Cabayol-Garcia L. , Castander F. J. , Siudek M. , Wittje A. , Hildebrandt H. , Casas R. , Tallada-Crespí P. , Garcia-Bellido J. , Sanchez E. , Sevilla-Noarbe I. , Miquel R. , Padilla C. , Renard P. , Carretero J. , De Vicente J.
Published: November 2024

We present photometric redshifts for 1 341 559 galaxies from the Physics of the Accelerating Universe Survey (PAUS) over 50.38 deg2 of sky to iAB = 23. Redshift estimation was performed using DEEPz, a deep learning photometric redshift code. We analysed the photometric redshift precision when varying the photometric and spectroscopic samples. Furthermore, we examined observational and instrumental effects on the precision of the photometric redshifts, and we compared photometric redshift measurements with those obtained using a template method-fitting BCNz2. Finally, we examined the use of photometric redshifts in the identification of close galaxy pairs. We find that the combination of samples from the W1 and W3 fields in the training of DEEPz significantly enhances the precision of photometric redshifts. This also occurs when we recover narrow-band fluxes using BB measurements. We show that DEEPz determines the redshifts of galaxies in the prevailing spectroscopic catalogue used in the training of DEEPz with greater precision. For the faintest galaxies (iAB = 21 − 23), we find that DEEPz improves over BCNz2 both in terms of the precision (20–50% smaller scatter) and in returning a smaller outlier fraction in two of the wide fields. The catalogues were tested for the identification of close galaxy pairs, showing that DEEPz is effective for the identification of close galaxy pairs for samples with iAB <  22.5 and redshift 0.2 <  z <  0.6. In addition, identifying close galaxy pairs that are common between DEEPz and BCNz2 is a promising approach for improving the accuracy of the catalogues of these systems.
Organizational Culture and Adaptability in Public Sector Organizations: Bibliometric Analysis and Literature Review
Authors: Al-Azkiya Muhammad Emir , Sudarmo Sudarmo , Ansoriyah Faizatul
Published: November 2024

The VUCA era is a manifestation of Volatility, Uncertainty, Complexity, and Ambiguity, which every organization, including public sector organizations, is currently facing. The COVID-19 pandemic is a real manifestation of the VUCA condition. Organizational culture plays an important role in dealing with the emergence of VUCA because a strong culture allows organizations to adapt effectively to change. This study seeks to explore the development of organizational culture and adaptability in public sector organizations. The research method used in this study is a mixed method using bibliometric analysis (quantitative) and literature review (qualitative). The findings of this study reveal that organizational culture is an interesting research topic because research that raises this topic has more than 18,000 documents in the scope of social sciences indexed in the Scopus database on June 2020. Research trends that raise organizational culture also continue to change over time, where research that discusses the issue of adaptability in public sector organizations still needs to be carried out. These studies highlight three aspects, namely organizational culture and its relationship to performance, organizational adaptability, and employee adaptability in the public sector.
Quels indicateurs pour évaluer la réflexivité des formateurs en simulation en santé ?
Authors: Philippot Guillaume , Verquin Savarieau Béatrice , Deligny Christophe
Published: November 2024

Contexte et problématique : La simulation en plaçant les apprenants comme acteurs de leurs stratégies d’apprentissage, participe au changement de paradigme de la pédagogie universitaire en médecine. Avec la réflexivité au cœur des débriefings, cette méthode pédagogique contribue au développement professionnel des formateurs en simulation. Nous explorerons les concepts de réflexivité en formation, développement professionnel et mesure de la réflexivité puis tenterons d’identifier les critères de réflexivité des formateurs au fil de leur parcours d’apprentissage. Objectif : Mesurer le développement de la réflexivité des formateurs en simulation en santé au fil de leur parcours et tenter de valider une échelle d’autoévaluation de leur réflexivité. Méthodes : Cette recherche sur la formation de formateurs en simulation est réalisée au centre d’enseignement et de simulation en santé de Martinique. L’échantillon est composé de 20 formateurs auquel nous soumettons un questionnaire à trois moments de la formation (début (T1), milieu (T2) puis fin de tutorat (T3)). Nous explorons ainsi une échelle de mesure de la réflexivité à partir d’une mise en lien de trois groupes de critères (G), (C) et (D) issus de travaux de recherche préexistants [1–3], à partir de calculs intégrant l’Alpha de Cronbach, pour étudier la cohérence de cette mise en lien. Résultats : Dans cet article, nous mettons en évidence une excellente cohérence interne de l’ensemble des critères (C) et (D) pour évaluer la réflexivité à T1 et T2. Une amélioration de la notation des critères apparaît en T2 par rapport à T1 avec une différence statistiquement significative. Conclusion : Il apparaît pertinent de transférer ces indicateurs d’évaluation des traces de la réflexivité à la conception d’une échelle d’autoévaluation de la réflexivité des formateurs en simulation.
A New Management Strategy for Hemimasticatory Spasm
Authors: Zhang Zhongding , Lu Datan , Ying Tingting , Li Shiting , Zhao Hua
Published: November 2024

Background Hemimasticatory spasm (HMS) is an uncommon movement disorder of the trigeminal motor rootlet characterized by unilateral, involuntary, and paroxysmal contractions of the muscles of mastication. The mechanisms for HMS are still unclear, and an efficient treatment strategy still needs to be developed. This study aims to investigate the clinical features and surgical treatment of HMS.

Methods Twelve patients with HMS were included in our study. The patient data regarding clinical characteristics, neuroimaging presentations, intraoperative findings, and treatment outcomes were analyzed retrospectively. Highly selective trigeminal motor root rhizotomy (HSTR) combined with microvascular compression was performed in nine cases with neurovascular conflict, whereas three patients without vascular compression underwent HSTR only.

Results Intraoperative findings showed that there were two patients with six branches, two patients with five branches, and the remaining patients with three to four branches of the trigeminal motor roots. Seven patients had two motor branches severed, three patients had one motor branch severed, and two patients each had three motor branches severed. Nine patients recovered uneventfully and showed no signs of spasms, and the remaining two patients experienced complete disappearance of symptoms within 3 months after surgery. In one patient, the symptoms disappeared immediately after surgery but recurred 2 years later.

Conclusion The surgical procedures of HSTR can significantly alleviate the clinical symptoms of patients with HMS without serious complications.
Enhancing financial sustainability: the power of intellectual capital in India’s renewable energy industry
Authors: Weqar Faizi , Shajar Syed Noorul , Kashif Mohammad , Noman Saqib , Khan Mohsin
Published: November 2024

The main objective of this research article is to examine the effect of intellectual capital (IC) and its dimensions on the financial performance (FP) of the Indian renewable energy industry, guided by the Resource-Based View (RBV). The study employed data from 36 solar and 39 wind sector companies for six years, from 2017 to 2022. Moreover, the modified value added intellectual coefficient (MVAIC) model was used to measure the company’s IC. Further, the paper uses panel data regression analysis to examine the above-mentioned objectives. The results showed that IC improves the earnings and profitability of solar sector companies, while for wind sector companies, it only helps boost their profitability. Contrary to the expectation, human capital efficiency (HCE) failed to show any effect on the FP of the Indian solar sector companies. However, HCE positively moderates the relationship between structural capital efficiency (SCE) and FP, as well as relational capital efficiency (RCE) and FP. For the wind sector companies, HCE significantly and positively affects the FP; however, HCE negatively moderates SCE and profitability while positively for capital employed efficiency (CEE) and FP. This research adds new data from an industry that has previously received little attention (i.e. Indian renewable energy industry), thus broadening the research on the relationship between IC and FP. Moreover, the study may provide in-depth insights into the MVAIC dimensions as it discovers the moderating effect of human capital in boosting the company’s FP.
Concentration dependence of the softening effect in Pb–Sn and Pb–Bi alloys at the superconducting transition point
Authors: Startsev V. I. , Abraimov V. V. , Sollatov V. P.
Published: November 2024

A study has been made of the effects of small amounts of tin and bismuth on the softening effect δϵns for lead single crystals at the superconducting transition point. Experiment shows that the magnitude of the softening κδϵns shows a complicated nonmonotonic dependence on the impurity concentration in the superconductor; the measurements are compared with conclusions from existing theories of the effect.
Transverse acoustoelectric effect in InSb single crystals
Authors: Roi B. F. , Kirillov S. E.
Published: November 2024

The appearance of a transverse acoustoelectric effect (TAEE) in single crystals of the n-type piezosemiconductor InSb is studied. Experiments were conducted at a temperature of 4.2 °K using ultrasonic waves in the frequency range 200–900 MHz in magnetic fields of up to 60 kOe. The nature of the formation of longitudinal and transverse acoustoelectric (AE) potentials along different crystallographic directions in the piezosemiconductor is investigated. The amplitude dependence of the TAEE on the intensity of the injected ultrasonic wave and the effect of strong magnetic fields on the nature of the formation of TAEE and AE potentials in InSb is investigated. The experimental results allow us to advance a hypothesis regarding the mechanism of TAEE formation.
Polyexciton absorption of light by oxygen crystals
Authors: Gaididei Yu. B. , Glushkov L. P. , Loktev V. M. , Pavloshchuk V. A. , Prikhot'ko A. F. , Shanskii L. I.
Published: November 2024

The results of detailed studies of the absorption bands of solid oxygen in the vicinity of 30,000 cm−1 are reported. It is shown that in addition to bimolecular transitions the spectrum displays multiple-particle transitions (involving three or four molecules). The authors suggest an interpretation of the temperature dependence of the integrated intensity of the bands caused by transitions with the excitation of three- and four-quasiparticles and calculate the fine structure of the spectrum.
Effect of resonance oscillations of the order parameter on the tunnel current in superconductors
Authors: Mitsai Yu. N. , Rozhavskii A. S.
Published: November 2024

The effect of resonance oscillations of the order parameter on the tunnel current in an S-I-S system is analyzed here. It is shown that anomalies of the Riedel kind characterize the quasiparticle current. The analysis here applies to temperatures below Tc.
Regular sloshing modes in irregular cavities using metabathymetry
Authors: Anglart Adam , Maurel Agnès , Petitjeans Philippe , Pagneux Vincent
Published: November 2024

We present a comprehensive investigation, combining numerical simulations and experimental measurements, into the manipulation of water waves and resonance characteristics within closed cavities utilizing anisotropic metamaterials. We engineer the anisotropic media with subwavelength-scale layered bathymetry through the application of coordinate transformation theory and the homogenization technique to a fully three-dimensional linear water wave problem. Experimental and numerical analyses of deformed cavities employing anisotropic metamaterial bathymetry demonstrate regular sloshing mode patterns and eigenfrequencies akin to those observed in rectangular reference cavities with flat bathymetry. Our study underscores the potential of water wave metamaterials for establishing robust anisotropic metabathymetry for the precise control of sloshing modes.
Field-free spin–orbit torque devices for logic and neural network applications
Authors: Lin Chun-Yi , Hsieh Jui-Yu , Wang Po-Chuan , Tsai Chia-Chin , Pai Chi-Feng
Published: November 2024

Robust field-free spin–orbit torque (SOT) switching plays an essential role in realizing practical SOT-based magnetic memories and logic devices. Leveraging the strong interlayer Dzyaloshinskii–Moriya interaction, field-free SOT switching is achieved with a threshold switching current density of 5.4 × 1010 A/m2. By exploiting the advantage of separated read–write paths, we demonstrate fundamental logic operations such as AND, OR, and NOT in a dual-channel SOT Hall bar device. We further explore the application of a digital SOT magnetic random access memory (MRAM) design in addressing the issue of the low ON/OFF ratio of the conventional spin-transfer torque MRAM, highlighting its potential for neural network applications. Our simulation results show that using digital SOT MRAM can achieve a classification accuracy of 92.2% for the MNIST dataset, outperforms the analog SOT MRAM case (<10%), and presents remarkable improvements in power and time efficiencies compared to the SRAM case. These findings establish digital SOT MRAM as a frontrunner for edge artificial intelligence applications and offline inference.
A connectivity dependent model for electrical properties of multiphase media
Authors: Zhang Yigaofei , Chen Bowen , Yang Xiaodong , Wu Xiaoping
Published: November 2024

Determining the effective electrical properties of a multiphase medium is essential for understanding its performance. However, accurately characterizing the internal structure and calculating the effective electrical properties of complex multiphase media can be challenging, often resulting in divergent results from different models. In this study, we propose a connectivity dependent model for mixed media based on the effective medium approximation, which incorporates structural influences. This model simplifies itself to analytical forms in specific scenarios, such as simple series and parallel configurations. Our model demonstrates two key advantages: First, the model parameters depend solely on the shape distribution of each phase within the medium, making it applicable to multiphase systems (≥3) without requiring additional corrections. Second, it can predict the percolation threshold and provide insights into permeability and connectivity analyses of the medium. We demonstrate the effectiveness and versatility of our model through a series of parameter analyses and comparisons with experimental data.
Meijer-G and other resummation strategies for the Møller–Plesset perturbation series
Authors: Zhao Yilin , Zhang Wenbiao , Rong Chunying , Ayers Paul W.
Published: November 2024

We compare various resummation techniques on truncated Møller–Plesset perturbation series. Our main results are for Padé, Borel–Padé, and Meijer G resummation techniques. All these resummation techniques improve the energies from truncated Møller–Plesset perturbation theory when the perturbation series is not-too-ill-behaved, but the Meijer-G resummation is arguably the best resummation, at least for low orders. An especially useful feature of the Meijer-G resummation is when it is unreliable, the predicted energy often has a nonnegligible imaginary part, making it possible to preemptively screen out some unreliable results.
Controllable gradient piezoelectric properties in ferroelectric single crystals
Authors: Jin Xinyu , Qiu Ming , Meng Xiangda , Wang Yu , Xing Bohan , Wen Xing , Ruan Jinyu , Huang Xiaolin , Wang Xiaoou , Hu Chengpeng , Tan Peng , Tian Hao
Published: November 2024

Functional gradient materials (FGMs) possess gradient-varying properties, which make them important in applications for connecting different materials and inhomogeneous environments. Ferroelectric single crystals have multiple excellent physical properties, but it is difficult to design gradient properties during the crystal growth. Here, a method is reported to achieve gradient piezoelectric properties in the tetragonal Mn&Fe-doped KTa1−xNbxO3 (Mn&Fe: KTN) crystals by alternating current poling and internal strain design. Furthermore, opposite piezoelectric coefficients are obtained in the direction perpendicular to the applied electric field, with a gradient variation from −221 to 227 pC/N. This phenomenon has been revealed to result from the co-regulating effect of flexoelectric field and alternating current electric field on defect dipoles and domain structures. This study contributes to the fabrication of functional gradient piezoelectric single crystals and expands the application scenarios of FGMs.
Tornado scar on the Nullarbor Plain, Australia
Authors: Lipar Matej
Published: November 2024

A newly discovered erosional scar on the Nullarbor Plain in southern Australia was analysed and hypothesised to be a consequence of a tornado event. The scar, identified using satellite imagery, stretches ~11 km in length and varies between 160 and 250 m in width, with notable cycloidal marks indicating activity of suction vortexes. The timing of the scar formation, constrained by Landsat and Sentinel imagery, is between 16 and 18 November 2022, coinciding with a significant weather event on 17 November 2022. The scar’s characteristics and the associated weather patterns strongly suggest it was formed by a tornado. Based on the scar’s dimensions and the pattern of cycloidal marks, the tornado’s strength is estimated to be within the F2 or even F3 category on the Fujita scale, with wind speeds likely exceeding 200 km h–1, moving in an eastward direction and swirling clockwise.
A noodle in a haystack: determining the conservation status of the rare and Data Deficient Ravensthorpe Range slider, Lerista viduata
Authors: Bonifacio Luke R. , Farquhar Jules E. , Pili Arman N. , Walsh Jessica C. , Chapple David G.
Published: November 2024

Context One-seventh of the ~157,000 species assessed by the IUCN Red List of Threatened Species are Data Deficient (DD), with insufficient information to assess their extinction risk. Such a statistic is concerning from a conservation perspective because more than half are predicted to be threatened by extinction, yet they are generally neglected from conservation priority. Aims Here, we aimed to improve ecological knowledge, and inform the conservation status of, the DD Ravensthorpe Range slider (Lerista viduata), a historically rare skink confined to Western Australia’s Ravensthorpe Range. Methods A detailed framework was developed to improve data on attributes integral to the species’ IUCN Red List assessment (e.g. distribution, threats, population size): collation of historical records, fieldwork within and around its known range, preserved specimen analysis, on-ground and spatial analysis of threats, and inference from ecologically similar species. Key results We found that L. viduata is threatened under multiple IUCN Red List criteria (B1ab[i,ii,iii,v], B2ab[i,ii,iii,v], C2ab[ii], D2), and overall should be considered Critically Endangered. This status is based on its Extent of Occurrence (32 km2) being <100 km2, occurrence at one location (defined by the threat of fire), and an inferred continuing decline in its distribution and habitat parameters. The species’ small estimated population size (3,514–9,276 mature individuals) also renders it extinction prone. Conclusions We demonstrate that L. viduata, long perceived as DD, should be reclassified as Critically Endangered, and is of the utmost conservation concern. Implications Our study reiterates the need for DD species to receive greater consideration in conservation research and action.
Household reduction of gas consumption in the energy crisis is not explained by individual economic incentives
Authors: Dertwinkel-Kalt Markus , Feldhaus Christoph , Ockenfels Axel , Sutter Matthias
Published: November 2024

In response to the disruption of gas supplies from Russia following the invasion of Ukraine in 2022, European politicians and public utilities appealed to citizens and customers to conserve natural gas. Moreover, they strengthened economic incentives for gas conservation. In fact, a substantial amount of natural gas was saved during the winter of 2022/23. This raises the question to what extent this success is attributable to government and corporate means to foster energy conservation in the crisis, including energy policies such as the German government’s “gas price brake,” gas-saving programs launched by public utilities, and consumers’ individual pricing schemes. We analyzed the effectiveness of these means using a survey and a field experiment with a German gas supplier and show that, while household savings during the crisis were substantial, economic incentives did not significantly change behavior. Indeed, demand for gas is largely price inelastic. A large majority of consumers do not understand the incentives arising from the gas price brake, and when they do, they do not respond. Likewise, consumers do not react to the design of the utilities’ gas-saving program. These findings suggest that i) citizens’ response to marginal individual economic incentives contributes little to overall gas savings, and ii) the crisis, along with the extensive societal engagement it generated, likely shifted the public’s mindset about energy consumption, making conservation a social priority.
Indirect reciprocity under opinion synchronization
Authors: Murase Yohsuke , Hilbe Christian
Published: November 2024

Indirect reciprocity is a key explanation for the exceptional magnitude of cooperation among humans. This literature suggests that a large proportion of human cooperation is driven by social norms and individuals’ incentives to maintain a good reputation. This intuition has been formalized with two types of models. In public assessment models, all community members are assumed to agree on each others’ reputations; in private assessment models, people may have disagreements. Both types of models aim to understand the interplay of social norms and cooperation. Yet their results can be vastly different. Public assessment models argue that cooperation can evolve easily and that the most effective norms tend to be stern. Private assessment models often find cooperation to be unstable, and successful norms show some leniency. Here, we propose a model that can organize these differing results within a single framework. We show that the stability of cooperation depends on a single quantity: the extent to which individual opinions turn out to be correlated. This correlation is determined by a group’s norms and the structure of social interactions. In particular, we prove that no cooperative norm is evolutionarily stable when individual opinions are statistically independent. These results have important implications for our understanding of cooperation, conformity, and polarization.
Determining initial conditions for nonlinear hyperbolic equations with time dimensional reduction and the Carleman contraction principle
Authors: Dang Trong D , Nguyen Loc H , Vu Huong T T
Published: November 2024

This paper aims to determine the initial conditions for quasi-linear hyperbolic equations that include nonlocal elements. We suggest a method where we approximate the solution of the hyperbolic equation by truncating its Fourier series in the time domain with a polynomial–exponential basis. This truncation effectively removes the time variable, transforming the problem into a system of quasi-linear elliptic equations. We refer to this technique as the ‘time dimensional reduction method.’ To numerically solve this system comprehensively without the need for an accurate initial estimate, we used the newly developed Carleman contraction principle. We show the efficiency of our method through various numerical examples. The time dimensional reduction method stands out not only for its precise solutions but also for its remarkable speed in computation.
Coenhancement of optical transmission and Faraday effect with magnetic plasmonic nanopillars
Authors: Luo Peng , Wang Qiang , Wang Han
Published: November 2024

Coenhancement of optical transmission and the Faraday effect are always the goals to pursue for photoelectric devices, while the current research almost concentrated on the properties based on gratings and photonic crystal structures. Nanopillars (NPs) are structures with a relatively simple preparation that have been widely used in many fields, where the Faraday effect has been rarely studied. In this work, a Faraday rotator in the wavelength range of 500–800 nm is proposed based on bismuth–iron garnet (BIG) with magnetic plasmonic NPs structure, in which the hemispherical shaped silver covered on top and silica used as the substrate for enhancement effect. Through this rotator, two peak values for both Faraday rotation angle and transmittance can be achieved, no matter what the wavelength changes are. The transmittance, Faraday rotation angle, and figure of merit (FOM) can be controlled by tuning the thickness and lattice constant of the BIG NPs, the radius of the silver hemisphere, and the external magnetic field. Furthermore, the physics mechanism of the large Faraday effect and extraordinary optical transmission is explained by employing the electric field distribution diagrams. Finally, the optimized FOM simply can be raised to 0.9, achieving well overall performance in the visible light range. The results have certain values for achieving simpler and better performance of magneto-optical devices under visible wavelength range, such as optical isolators and magneto-optical sensors.
Integrating chromosome conformation and DNA repair in a computational framework to assess cell radiosensitivity*
Authors: Andriotty Matthew , Wang C-K Chris , Kapadia Anuj , McCord Rachel Patton , Agasthya Greeshma
Published: November 2024

Objective. The arrangement of chromosomes in the cell nucleus has implications for cell radiosensitivity. The development of new tools to utilize Hi-C chromosome conformation data in nanoscale radiation track structure simulations allows for in silico investigation of this phenomenon. We have developed a framework employing Hi-C-based cell nucleus models in Monte Carlo radiation simulations, in conjunction with mechanistic models of DNA repair, to predict not only the initial radiation-induced DNA damage, but also the repair outcomes resulting from this damage, allowing us to investigate the role chromosome conformation plays in the biological outcome of radiation exposure. Approach. In this study, we used this framework to generate cell nucleus models based on Hi-C data from fibroblast and lymphoblastoid cells and explore the effects of cell type-specific chromosome structure on radiation response. The models were used to simulate external beam irradiation including DNA damage and subsequent DNA repair. The kinetics of the simulated DNA repair were compared with previous results. Main results. We found that the fibroblast models resulted in a higher rate of inter-chromosome misrepair than the lymphoblastoid model, despite having similar amounts of initial DNA damage and total misrepairs for each irradiation scenario. Significance. This framework represents a step forward in radiobiological modeling and simulation allowing for more realistic investigation of radiosensitivity in different types of cells.
Statistical biases correction in channelized Hotelling model observers
Authors: Desponds Lionel
Published: November 2024

Objective. Channelized Hotelling model observers are efficient at simulating the human observer visual performance in medical imaging detection tasks. However, channelized Hotelling observers (CHO) are subject to statistical biases from zero-signal and finite-sample effects. The point estimate of the d′ value is also not always symmetric with exact confidence interval (CI) bounds determined for the infinitely trained CHO. A method for correcting these statistical biases and CI asymmetry is studied. Approach. CHO d′ values and CI bounds with hold-out and resubstitution methods were computed for a range of 200 × 200 pixels images from 20 to 10 000 images for 10, 40 and 96 channels from a set of 20 000 images with gaussian coloured simulated noise and simulated signal. The median of the non-central F cumulative distribution (F′), which is the CHO underlying statistical behaviour for the resubstitution method, was computed, and compared to d′ values and CI bounds. A set of experimental data was used to evaluate F′ median values. Main results. The F′ median allows to get accurate corrected simulated d′ values down to zero-signals. For small d′ values, the variation of d′ values with the inverse of number of images is not linear while the F′ median allows a good correction in such conditions. The F′ median is also inherently symmetric with regards to the CI. With experimental data, F′ median values in a range of about 1–10 d′ values were within −0.8% to 4.7% of linearly extrapolated values at an infinite number of images. Significance. The F′ median correction is an effective simultaneous correction of the zero-signal statistical bias and finite-sample statistical bias, and of CI asymmetry of CHO.
Quantum optimal control of molecular coherent states
Authors: Belfakir Abdessamad , Belhaj Adil , Hassouni Yassine , Herzallah Randa , Ratnani Ahmed
Published: November 2024

In this paper, we address the optimal control problem in molecular systems, focusing on transitions within coherent states characterised by complex coefficients. Employing Hölder’s inequality, we establish a mathematical relationship between the energy requirement and the distance separating the initial and the target coherent states. A key part of our study is the application of this framework to the H2O molecule, specifically examining the local OH bond. Here, we demonstrate how energy requirements for the state transitions are influenced by the distance between these states. Furthermore, we investigate the effects of a heat bath coupled to the system, by analysing its impact on transferring the molecular system to different final coherent states. These coherent states are defined as almost eigenvectors of the Generalised Heisenberg Algebra (GHA) annihilation operator. By using the Perolomov approach, another type of coherent states for the Morse potential associated with the GHA can be constructed. By leveraging the GHA structure, we revisit and analyse Morse coherent states previously established for certain diatomic molecules, offering a deeper insight into the dynamics of state transitions under various conditions.
Entropy measures of silicon nanotubes using degree based topological indices
Authors: Fraz Hafiz Muhammad , Ali Kashif , Nadeem Muhammad Faisal
Published: November 2024

Nanotechnology is an emerging field in the modern era, and nanotubes, tube-like structures derived from various materials, including carbon, silicon, and boron, are extensively used in nanosciences, particularly in medicine, energy, and the synthesis of new compounds. The physical stability and chemical properties of nanotubes are topics of significant interest due to their high impact. A topological index is an invariant numerical value associated with certain physicochemical properties and aids in exploring key insights into a chemical compound. In this paper, we compute several degree-based topological indices, including the first Zagreb, second Zagreb, multiplicative first Zagreb, multiplicative second Zagreb, hyper Zagreb, atom-bond connectivity, sum connectivity, and Sombor indices. We also calculate the related entropies for two silicon nanotubes. A numerical comparison of the different values of the indices above and a regression model is also established.
A novel multi-delay feedback digital chaos anti-degradation algorithm and its application in key generator
Authors: Xu Yaoqun , Zhang Tianqi , Liu Jiaoyang , You Zelong
Published: November 2024

Under conditions of finite accuracy, chaotic systems will exhibit a sequence of dynamic degradation issues. Such chaotic systems cannot be considered strictly chaotic, and their applications will be significantly impacted. A control approach is given to handle this problem, which combines parameter perturbation and multi-delay dynamic feedback. This approach utilizes a pseudo-random sequence produced by a high-performance chaotic system to disturb the parameters, then loops back the output of the previous state to the input based on its activity. Numerical studies were conducted to verify the usefulness of this enhanced technique when used in both one-dimensional and two-dimensional chaotic systems. Using a two-dimensional chaotic system as an example, it was confirmed that the enhanced digital chaotic system is extremely responsive to little variations in the starting value. Subsequently, a key generator was created, which successfully passed the NIST randomness test. The experimental results demonstrate that the enhanced digital chaotic system has favorable chaotic properties within the constraints of low precision.
Exploring giant dielectric constant in Dy2CoMnO6: evidence of non-overlapping small polaron hopping
Authors: Pokhrel Dipankar , Sahu Somnath , Singh Hodam Karnajit , Tangi Malleswararao , Sridhar V , Pamu D
Published: November 2024

Perovskites, both natural and synthetic, form a large class of materials are a vast class of materials with significant technological relevance due to their remarkable physical properties, such as superconductivity, magnetoresistance, ionic conductivity, and diverse dielectric behaviors. In this study, the dielectric relaxation and transport properties of the double perovskite Dy2CoMnO6(DCMO) synthesized via high-energy ball milling are investigated. DCMO exhibits a notably large dielectric constant, attributed to a combination of intrinsic and extrinsic mechanisms. Frequency-dependent dielectric studies reveal non-Debye-like behavior, validated by augmented Havriliak-Negami function fitting. Impedance spectroscopy confirms the semiconducting nature of DCMO, showing a negative temperature coefficient of resistance, and identifies two distinct relaxation processes corresponding to grain boundaries and grain interiors thereby highlighting the impact of microstructure and defects. The Cole-Cole plot further supports the non-Debye behavior, while thermally activated relaxation suggests damped charge carrier dynamics at grain boundaries. Conduction analysis using augmented Jonscher's power law reveals non-overlapping small polaron tunneling as the dominant mechanism driving both the dielectric response and transport properties, with DC conductivity suggesting a three-dimensional variable range hopping model. These results provide significant insights into the dielectric and transport properties of DCMO, highlighting its promising potential for advanced electronic applications.
Enhancing room temperature thermoelectric efficiency in zigzag phosphorene nanoribbon junctions through Quasi-Flat impurity bands
Authors: Al-Zubaidi Maha , Karbaschi Hossein , Sadeghizadeh Mozhgan , Ghanbari-Adivi Ebrahim , Soltani Morteza
Published: November 2024

In this study, a novel approach has been utilized to Please specify the corresponding author.explore the room temperature thermoelectric properties of zigzag phosphorene nanoribbon-based monolayer-bilayer-monolayer junctions. To achieve thermoelectric properties at room temperature, a quasi-flat energy band with limited width is required. It has been demonstrated, for the first time, that such bands can be observed by considering a junction of the monolayer and bilayer phosphorene nanoribbons. By adjusting the ribbon widths, quasi-flat bands are produced. This geometrical problem is solved using analytical calculations for a general system and applied to phosphorene. We show that the edge states of phosphorene resemble a one-dimensional tight-binding system, with a close agreement between their results. Using the introduced approach, we calculate the electronic energy band structure of the specified system. Initially, we demonstrate that the formation of zigzag monolayer-bilayer-monolayer junctions can lead to the emergence of quasi-flat impurity bands within the energy bandgap. Furthermore, we show that utilizing these structures at room temperature, across a wide range of lead temperature differences, results in significant output electrical power and improved thermoelectric efficiency. The electrical power and thermoelectric efficiency are examined as functions of applied bias voltage and average chemical potential. Additionally, we explore how the output electrical power, thermoelectric efficiency, and efficiency at maximum power vary with the temperature difference between the leads at the ends of the structure.
Constructing viable interacting dark matter and dark energy models: a dynamical systems approach
Authors: Ashmita  , Banerjee Kinjal , Das Prasanta Kumar
Published: November 2024

We study the evolution of k = -1 FLRW cosmological models for two interacting Dark Matter-Dark Energy Models using dynamical system analysis. Since we are interested in late time evolution, the sign of the interaction term is chosen such that it facilitates the transfer of energy from dark matter to dark energy. We also explore the k = 0 invariant subspace of these models. We find that both these models have sectors which have a stable fixed point where we can recover an accelerating universe with a negative equation of state. This indicates these can be viable models for our universe. We also rule out certain sectors of these models because they do not give the correct late time observational features. We observe that although we start with a dust-like Dark Matter, its effective equation of state evolves due to its interaction with Dark Energy. As a result, the Dark Matter can display features of stiff matter and exotic matter in the course of evolution.
Red-shift effect on the zero-field splitting for negatively charged nitrogen-vacancy centres in diamond
Authors: Wang Zheng , Zhang Jintao , Feng Xiaojuan , Xing Li
Published: November 2024

The zero field splitting (ZFS) quantifies the energy difference for the ground electron spin-triplet of a negatively charged nitrogen-vacancy centre3

3

The term of negatively charged nitrogen-vacancy centre is abbreviate as NV centre in this paper.

in the absence of external fields in a diamond sample. ZFS is a key parameter for using NV centres as quantum sensors for probes of magnetic and electric fields, temperatures and strains. The ZFS is generally detected using coherent spin manipulation by sweeping microwaves (MWs) at frequencies close to resonance with the ZFS. In this article, we report our experimental observations of the red-shift effect on the ZFS as a function of the MW power for two different thermal environments of the sample. We find asymptotic properties of the red shifts of the ZFS. Given the identical initial thermal equilibrium states of the sample, the differences in the raw values of the ZFS between the two cases randomly vary from 47 kHz to 1505 kHz over the entire experimental range. According to the asymptotic approximation, the difference is reduced to 29 kHz–166 kHz with a standard deviation of 49 kHz, suggesting a significant elimination of the red-shift effect. To the best of our knowledge, no other study has addressed the quantification and elimination of the red shift-effect of the MW field dependence using the asymptotic approximation.
Preliminary characterization of a surface electrode Paul trap for frequency metrology
Authors: Madunic Josipa , Groult Lucas , Achi Bachir , Lauprêtre Thomas , Boudrias Alan , Roset Pierre , Soumann Valérie , Kersalé Yann , Hafiz Moustafa Abdel , Lacroûte Clément
Published: November 2024

We are developing a single-ion optical clock based on a surface-electrode (SE) trap that we will operate with 171Yb+ ions on the electric quadrupole transition at 435.5 nm. We present heating rate measurements performed with a prototype SE trap. We also introduce a new, micro-fabricated SE trapping chip using silicon on insulator technology. Electric tests were performed under ultra-high vacuum using a testing chip, including breakdown voltages measurements and flashover detection. We present suitable trapping parameters for this chip, as well as a road-map for improving its design.
Optically steered time scale generation at OP and NPL and remote comparisons
Authors: Abgrall M , Chupin B , Uhrich P , Lorini L , Le Targat R , Pointard B , Lodewyck J , Tunesi J , Tran D B A , Parsons A O , Tofful A , Robertson B I , Johnson M Y H , Feng C-H , Schioppo M , Curtis E A , Hill I R , Godun R M , Margolis H S
Published: November 2024

In this paper, we present real-time optically steered time scales generated simultaneously at the Observatoire de Paris (OP) and the National Physical Laboratory (NPL). Throughout one month, experimental UTCx(k) time scales were generated concurrently in the two laboratories alongside the local operational UTC(k) time scales. The UTCx(k) time scales were based on hydrogen masers whose frequencies were calibrated by local optical frequency standards using optical frequency combs, with algorithms being developed for outlier filtering and frequency steering estimations in the two laboratories. The performance of the experimental time scales was assessed through local comparisons against the corresponding UTC(k) time scales, and also through remote comparisons performed both via Coordinated Universal Time (UTC) and by using the GPS Precise Point Positioning (PPP) technique. The two optically steered time scales remained within 4 ns of each other, outperforming the corresponding UTC(k) over the same period. To our knowledge, this is the first reported comparison of two independent “optical time scale” prototypes, and the results demonstrate the capability of optical clocks to produce operational time scales.