bluuebunny/crossref_metadata_2025 huggingface dataset:
RTBES Radiological Index for Quantitative Assessment of Tuberculosis Evolution: Development and Validation
Authors: Cuadras Patrícia , Rafart Gerard , Català Martí , Arias Lilibeth , Pérez Ricard , Martinson Neil , Rosenthal Alex , Gabrielian Andrei , Vashakidze Sergo , Tenesa Montserrat , Bechini Jordi , Vilaplana Cristina
Published: February 2025

Question addressed by the study

A radiological index capable of quantifying pulmonary tuberculosis (TB) disease progression on standard Chest X-Ray (CXR) could enhance clinical management and inform therapeutic decision-making. Our objectives were: to develop a radiological index that quantitatively assesses the progression of pulmonary TB in patients over the course of treatment and follow-up, to evaluate its usefulness by using CXRs from a cohort of TB patients, and to validate it with CXRs from an independent cohort of TB patients.

Materials/patients and methods

An index was developed to identify and classify patterns of radiological findings of both active and inactive pulmonary TB. This index was evaluated in a first cohort comprising a pseudonymized sample of serial CXRs from 21 TB patients at the Perinatal HIV Research Unit (PHRU) in South Africa and validated in a second, larger, independent cohort comprising 50 treated TB patients from the National Institute of Allergy and Infectious Diseases (NIAID) TB Data Portals. The relationship between index values for activity markers and patients’ clinical characteristics was also analysed.

Results

A radiological index, the RUTI-TB Evolution Score (RTBES), was created and validated in two cohorts, achieving 95.96% interobserver agreement (±2 points). In both cohorts, RTBES for active TB signs decreased over follow-up. Higher baseline RTBES correlated with male sex, higher bacterial loads, and extensive pulmonary involvement (including cavitation and pleural effusions). Baseline RTBES≥2 predicted unfavourable outcomes; 80% of failures/deaths occurred above this threshold.

Answer to the question

RTBES effectively quantified pulmonary TB severity and tracked treatment evolution on standard CXRs, showing promise as a prognostic tool to inform clinical decision-making.
Characterizing meniscal calcifications with photon counting-based dual-energy computed tomography
Authors: Nevanranta Eeva , Karjalainen Ville-Pauli , Brix Mikael , Hellberg Iida , Turkiewicz Aleksandra , Shakya Bijay , Önnerfjord Patrik , Ylisiurua Sampo , Sjögren Amanda , Elkhouly Khaled , Hughes Velocity , Tjörnstrand Jon , Saarakkala Simo , Englund Martin , Finnilä Mikko A.J
Published: February 2025

Meniscal calcifications are associated with meniscal degeneration and osteoarthritis (OA). However, differentiating between calcification types, such as basic calcium phosphate (BCP) and calcium pyrophosphate (CPP), remains challengingin vivo. Therefore, assessing new imaging possibilities is crucial in understanding the calcification pathologies and their relationship with OA. This study investigated dual-energy computed tomography combined with a photon counting detector (PCD-DECT) to identify calcifications in human meniscal samplesex vivo, using Raman spectroscopy as reference. 82 meniscus samples from 41 donors were imaged using PCD-DECT at 120kVp. Data were collected in two energy bins (20-50keV and 50-120keV) with an isotropic resolution of 37µm. Raman spectroscopy was used to classify the calcifications as BCP or CPP. Among 82 samples, Raman spectroscopy identified 36 samples with only either BCP or CPP calcifications, that were included in the subsequent analysis. Regression models were used to compare the dual-energy index (DEI) and to assess the low energy values for corresponding high energy values between calcification types. The highest difference observed between BCP and CPP in comparison of low energy values for corresponding high energy values was 166HU (95%CI: 73, 259) at high energy value of 500HU and the difference between DEI values was 0.035 (95%CI: 0.011, 0.059), suggesting a potential difference in the measured parameters of calcification types. To conclude, PCD-DECT allowed the measurement of BCP and CPP calcificationsex vivo, offering new potentialin vivoapplications in the future, which could help understand calcification processes and evaluate the efficacy of disease-modifying drugs targeting calcification inhibition.
Ensemble Post-hoc Explainable AI in Multivariate Time Series: Identifying Medical Features Driving Disease Prediction
Authors: Metsch Jacqueline Michelle , Hempel Philip , Maurer Miriam Cindy , Spicher Nicolai , Hauschild Anne-Christin
Published: February 2025

Despite the growing success of deep learning (DL) in multivariate time-series classification, such as 12-lead electrocardiography (ECG), widespread integration into clinical practice has yet to be achieved. The limited transparency of DL hinders clinical adoption, where understanding model decisions is crucial for trust and compliance with regulations such as the General Data Protection Regulation (GDPR) or the EU AI Act.

To tackle this challenge, we implemented a state-of-the-art 1D-ResNet in Pytorch that was trained on the large-scale Brazilian CODE dataset to classify six different ECG abnormalities. We employed the model on the German PTB-XL dataset, and evaluated its decision-making processes using 16 post-hoc explainable AI (XAI) methods. To assess the clinical relevance of the model’s attributions, we conducted a Wilcoxon signed-rank test to identify features with significantly higher relevance for each XAI method. We used an ensemble majority vote approach to validate whether the model has learned clinically meaningful features for each abnormality. Additionally, a Mann–Whitney U test was employed to detect significant differences in relevance attributions between correctly and incorrectly classified ECGs.

Overall, the model achieved sensitivity scores above 0.9 for most abnormalities in the PTB-XL dataset. However, our XAI analysis showed that the model struggled to capture clinically relevant features for some diseases. Certain XAI methods, including DeepLift, DeepLiftShap, and Occlusion, consistently highlighted clinically meaningful features across abnormalities, while others, such as LIME, KernelShap, and LRP, failed to do so. Moreover, some XAI methods demonstrated significant differences in attributions between correctly and incorrectly classified ECGs, highlighting their potential for enhancing model robustness and interpretability.

In conclusion, our findings underscore the importance of selecting suitable XAI methods tailored to specific model architectures and data types to ensure transparency and reliability. By identifying effective XAI techniques, this study contributes to closing the gap between DL advancements and their clinical implementation, paving the way for more trustworthy AI-driven healthcare solutions.
Data-driven Analysis of Fine-Scale Badger Movement in the UK
Authors: Furber Jessica Rachel , Delahay Richard , Cox Ruth , Woodroffe Rosie , O'Hagan Maria , Klus Stefan , Lo Iacono Giovanni , Chambers Mark , Lloyd David J.B.
Published: February 2025

Understanding animal movements at different spatial scales presents a significant challenge as their patterns can vary widely from daily foraging behaviours to broader migration or territorial movements. This challenge is of general interest because it impacts the ability to manage wildlife populations effectively. In this study, we conduct diffusion analysis based on European badger (Meles meles) movement data obtained from three different regions in the UK (Gloucestershire, Cornwall, and Northern Ireland) and fit a generalised linear mixed-effects model to examine the relationship between variables. We also feature a novel application of extended dynamic mode decomposition (EDMD) to uncover patterns relating to badger social organisation. By applying our approach to these different populations, we were able to assess its performance across a range of badger densities. A key result was that in some areas, EDMD clusters matched observed group home ranges, whilst in others, discrepancies likely arose because of population management interventions, such as badger culling. The methods presented offer a promising approach for studying territoriality and the impacts of management strategies on animal movement behaviour.
Fructose-1,6-bisphosphatase (FBPase) fine-tunes heterotrophic growth in cyanobacteria
Authors: Caliebe Frauke , Ojha Ravi Shankar , Gruber Marco , Boehm Marko , Shen Lu , Bräsen Christopher , Snoep Jacky L. , Forchhammer Karl , Hagemann Martin , Siebers Bettina , Gutekunst Kirstin
Published: February 2025

Cyanobacteria switch their carbon metabolism between photoautotrophy and heterotrophy during diurnal cycles. In cyanobacteria, the classical glycolytic control point is characterized by two catabolic phosphofructokinases (PFKs) and a bifunctional anabolic fructose-1,6-biphosphatase/sedoheptulose-1,7-biphosphatase (F/SBPase;slr2094) catalyzing two key reactions in the Calvin-Benson-Bassham (CBB) cycle. In addition,Synechocystispossesses a fructose-1,6-bisphosphatase (FBPase;slr0952) with yet unknown physiological function and biochemical properties. Hence, our aim was to investigate the FBPase and the interplay of the four enzymes in photoautotrophic and heterotrophic carbon metabolism.

We discovered that FBPase is specific for FBP, showing no SBPase activity, and unlike F/SBPase does not exhibit any biochemical regulatory properties. Growth studies with deletion mutants revealed that FBPase and PFKs play a major role under heterotrophic conditions. In contrast to F/SBPase, FBPase is not involved in the CBB cycle, but instead fine-tunes heterotrophic growth. Transaldolase cannot replace the function of SBPase in the CBB cycle.

In conclusion, the classical Embden-Meyerhoff-Parnass pathway control point, which is known to be mediated by the antagonistic enzyme pair PFK and FBPase in heterotrophic bacteria and eukaryotes, is also present inSynechocystis. We found redox-insensitive FBPases from plant chloroplasts to be closely related toSynechocystisFBPase, indicating that they might serve a similar function.

Highlight

Synechocystisfructose-1,6-bisphosphatase (slr0952) is unlike fructose-1,6-biphosphatase/sedoheptulose-1,7-biphosphatase (slr2094) monofunctional, not redox-regulated, and supports heterotrophy in darkness, despite catalyzing an anabolic reaction. Thus, presumably Slr2094 alone drives two Calvin-Benson-Bassham cycle key reactions.
Scoping review protocol- Scoping review Vitamin B12deficiency in long term metformin use and clinician awareness
Authors: Parsonage Ian , Wainwright David , Barratt Julian
Published: February 2025

Introduction

A relationship between long-term metformin use and vitamin B12deficiency has been long discussed in literature. Nonetheless, prior to 2022, there was no official guidance. In June 2022, the MHRA published advice, stating that low vitamin B12is now considered to be a common side effect. It advises checking levels in patients with symptoms of B12deficiency, as well as monitoring those at risk of B12deficiency.

Despite efforts to promote evidence-based practice, there is still a gap in the translation of research findings into policies and clinical practice. The above research has been shared widely in the academic and specialist Diabetes literature over a prolonged period. The purpose of the scoping review is to explore what evidence is available regarding clinicians’ awareness of the association between metformin use and vitamin B12deficiency in patients with T2DM and how this evidence is implemented into frontline clinical practice and what screening processes are recommended or exist?

Methods and analysis

This is a protocol for a scoping review to be guided by the Joanna Briggs Institute (JBI) methodology for scoping reviews20. The databases to be searched will include CINAHL, MEDLINE, EMBASE, British Nursing Index, via EBSCOhost. Sources of unpublished studies, policies and grey literature will include Google Scholar, the Cochrane Library, ProQuest Dissertations and Theses Open. Titles and abstracts of articles were reviewed by the authors. If articles were representative of the inclusion criteria, the articles went through a full-text review by the authors The results of the search and study inclusion/exclusion process will be reported and presented in a Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) flow diagram. Data will be extracted from papers, using the recommended JBI data extraction tool.

Strengths and limitations of this study

To the authors’ knowledge, this is the first scoping review to look at clinician awareness of Vitamin B12deficiency in long term metformin use.

Strengths include an extensive search of multiple databases, including grey literature.

As this is a scoping review, the quality of the evidence and risk of bias will not be evaluated.

The review is also limited to selected languages which may bias the evidence.
Single-cell multiomics of neuronal activation reveals context-dependent genetic control of brain disorders
Authors: Liang Lifan , Zhang Siwei , Wang Zicheng , Zhang Hanwen , Li Chuxuan , Duhe Alexandra C. , Sun Xiaotong , Zhong Xiaoyuan , Kozlova Alena , Jamison Brendan , Wood Whitney , Pang Zhiping P. , Sanders Alan R. , He Xin , Duan Jubao
Published: February 2025

Despite hundreds of genetic risk loci identified for neuropsychiatric disorders (NPD), most causal variants/genes remain unknown. A major hurdle is that disease risk variants may act in specific biological contexts, e.g., during neuronal activation, which is difficult to studyin vivoat the population level. Here, we conducted a single-cell multiomics study of neuronal activation (stimulation) in human iPSC-induced excitatory and inhibitory neurons from 100 donors, and uncovered abundant neuronal stimulation-specific causal variants/genes for NPD. We surveyed NPD-relevant transcriptomic and epigenomic landscape of neuronal activation and identified thousands of genetic variants associated with activity-dependent gene expression (i.e., eQTL) and chromatin accessibility (i.e., caQTL). These caQTL explained considerably larger proportions of NPD heritability than the eQTL. Integrating the multiomic data with GWAS further revealed NPD risk variants/genes whose effects were only detected upon stimulation. Interestingly, multiple lines of evidence support a role of activity-dependent cholesterol metabolism in NPD. Our work highlights the power of cell stimulation to reveal context-dependent “hidden” genetic effects.
A biophysical model of synaptic tagging-and-capture based on actin dynamics
Authors: Negri Francesco , Luboeinski Jannik , Tetzlaff Christian , Fauth Michael
Published: February 2025

According to the synaptic tagging-and-capture hypothesis, long-lasting (late-phase) plasticity requires the synthesis of plasticity-related proteins and the setting of a synaptic tag at the stimulated synapse. It has been hypothesized that this tag is implemented by the complex interplay between dendritic spine geometry and the scaffolding protein actin.

To test this, we propose a biophysically-grounded model of late-phase synaptic plasticity considering dynamic and stable actin pools and the size of the PSD in the synapse. In our model, the tag corresponds to the imbalance between the spine volume determined by actin and the volume that would be expected for the current PSD size.

We demonstrate the viability of the proposed model by showing that it can account for the experimentally observed synaptic plasticity induced by stimulation of a single synapse, as well as tag-resetting protocols, and heterosynaptic plasticity protocols involving two synapses.

Moreover, for the interaction of two consecutive stimuli at the same synapse within around up to an hour, plastic changes stack non-linearly, reminiscent of the spacing effect found in learning and memory studies.

In summary, our model both matches experiments and extrapolates well to a wide range of stimulation protocols. Thus, it will be ideally suited to serve as a basis to predict the plasticity effects emerging from the complex activity patterns in recurrent networks.
Congruent neuronal modulation across competing actions challenges the role of the substantia nigra in action selection
Authors: Hou Lingfeng , Grijalva Torres Sofia , Svedberg Daniel , Assad John
Published: February 2025

The basal ganglia are involved in the control of movement, but their exact role is unclear. Paradoxically, most of the inhibitory projection neurons in the main output nuclei increase firing around the time of movement; only a small fraction decrease firing. This antagonistic activity pattern could subserve action selection, with the small “decrease” population selectively disinhibiting the desired movement, and the larger “increase” population inhibiting competing movements. The action-selection hypothesis makes an implicit assumption: neurons that decrease firing to disinhibit a specific action should increase firing to inhibit that action when a different action is desired. To test this hypothesis, we recorded projection neurons in the substantia nigra pars reticulata (SNr) of mice trained to alternate between two different types of movements. Many SNr neurons showed a “ramping” pattern of pre-movement firing-rate modulation, with most neurons increasing firing, consistent with previous findings. However, contrary to the action-selection model, the overwhelming majority of SNr neurons exhibited congruent modulation between the competing actions, either increasing or decreasing their firing rates for both actions; only a small fraction of neurons exhibited opposite signs of modulation. We could not ascribe the congruent modulation to potential uninstructed movements. Our results are not easily reconciled with simple antagonistic mechanisms for action selection in the basal ganglia output nuclei. We also found that ramping activity in SNr neurons typically began hundreds of ms before self-timed and spontaneous movements, in contrast to previous findings suggesting that basal ganglia output is modulated too late to be involved in movement initiation. Our findings suggest constraints – and raise new questions – about the role of the basal ganglia in movement initiation and action selection.
Bosonic quantum error correction with neutral atoms in optical dipole traps
Authors: Bohnmann Leon H. , Locher David F. , Zeiher Johannes , Müller Markus
Published: February 2025

Bosonic quantum error correction codes encode logical qubits in the Hilbert space of one or multiple harmonic oscillators. A prominent class of bosonic codes is that of Gottesman-Kitaev-Preskill (GKP) codes of which implementations have been demonstrated with trapped ions and microwave cavities. In this paper, we investigate theoretically the preparation and error correction of a GKP qubit in a vibrational mode of a neutral atom stored in an optical dipole trap. This platform has recently shown remarkable progress in simultaneously controlling the motional and electronic degrees of freedom of trapped atoms. The protocols we develop make use of motional states and, additionally, internal electronic states of the trapped atom to serve as an ancilla qubit. We compare optical tweezer arrays and optical lattices and find that the latter provide more flexible control over the confinement in the out-of-plane direction, which can be utilized to optimize the conditions for the implementation of GKP codes. Concretely, the different frequency scales that the harmonic oscillators in the axial and radial lattice directions exhibit and a small oscillator anharmonicity prove to be beneficial for robust encodings of GKP states. Finally, we underpin the experimental feasibility of the proposed protocols by numerically simulating the preparation of GKP qubits in an optical lattice with realistic parameters.

Published by the American Physical Society
2025
Emergent spinon-holon Feshbach resonance in a doped Majumdar-Ghosh model
Authors: Linsel Simon M. , Schollwöck Ulrich , Bohrdt Annabelle , Grusdt Fabian
Published: February 2025

Experimental and numerical spectroscopy have revealed rich physics in antiferromagnets, in particular in frustrated and doped systems. The Majumdar-Ghosh (MG) model has an analytically known spin-disordered ground state of dimerized singlets as a result of magnetic frustration. Here we study the single-hole angle-resolved photoemission spectrum (ARPES) of a doped MG model, where we introduce a spin-hole interaction that is experimentally accessible with ultracold molecules. We report a bound spinon-holon ground state and clear signatures of a spinon-holon molecule state and polarons in the ARPES spectrum at different magnetizations. Moreover, we find signatures of an emergent Feshbach resonance with tunable interactions associated with the unbinding of the spinon and the holon. Our results provide new insights into the physics of dopants in frustrated t−J models and establish the latter as a new platform for studies of emergent few-body phenomena.

Published by the American Physical Society
2025
Benchmarking neutrino interaction models via a comparative analysis of kinematic imbalance measurements from the T2K, MicroBooNE, and MINERvA experiments
Authors: Filali W. , Munteanu L. , Dolan S.
Published: February 2025

Recent neutrino-nucleus cross-section measurements of observables characterizing kinematic imbalance from the T2K, MicroBooNE, and MINERvA experiments are used to benchmark predictions from widely used neutrino interaction event generators. Given the different neutrino energy spectra and nuclear targets employed by the three experiments, comparisons of model predictions to their measurements breaks degeneracies that would be present in any single measurement. In particular, the comparison of T2K and MINERvA measurements offers a probe of energy dependence, while a comparison of T2K and MicroBooNE investigates scaling with nuclear target. In order to isolate the impact of individual nuclear effects, model comparisons are made following systematic alterations to the nuclear ground state, final-state interactions, and multinucleon interaction strength. The measurements are further compared to the generators used as an input to DUNE/SBN and T2K/Hyper-K analyses. While no model is able to quantitatively describe all of the measurements, evidence is found for mismodeling of A-scaling in multinucleon interactions and it is found that tight control over how energy is distributed among hadrons following final-state interactions is likely to be crucial to achieving improved agreement. Overall, this work provides a novel characterization of neutrino interactions while offering guidance for refining existing generator predictions.

Published by the American Physical Society
2025
Doubly charm tetraquark channel with isospin 1 from lattice QCD
Authors: Meng Lu , Ortiz-Pacheco Emmanuel , Baru Vadim , Epelbaum Evgeny , Padmanath M. , Prelovsek Sasa
Published: February 2025

Experimentally, the doubly charm tetraquark channel ccq¯q¯ with q=u, d features an exotic hadron, Tcc, with isospin I=0 near the DD* threshold, while no peak was observed for I=1. We present a lattice QCD study of this channel with I=1, JP=1+, and mπ≃280  MeV. Finite-volume energies calculated across five charm quark masses consistently feature a positive energy shift with respect to noninteracting energies, indicating repulsive interaction at energies near the threshold. These energies are used to compute the DD* scattering amplitude using both the standard Lüscher method and the recently proposed effective field theory-based approach in the plane wave basis, which incorporates the long-range interactions and the left-hand cut. Both analyses render a small negative scattering length and a scattering amplitude that does not feature any poles in the energy region near the DD* threshold, in line with the LHCb results. We identify that the Wick contraction, resembling t-channel isovector-vector meson exchanges between D and D*, plays a key role in distinguishing between the I=0 and I=1 channels, leading to repulsion in the I=1 and attraction in the I=0 channel.

Published by the American Physical Society
2025
μ−→e−γ
in a muonic atom as a probe for effective lepton-flavor-violating operators involving photon fields
Authors: Uesaka Yuichi , Yamanaka Masato , Kuno Yoshitaka
Published: February 2025

We propose the μ−→e−γ process in a muonic atom as a novel means to investigate charged lepton flavor violation (CLFV). We demonstrate its sensitivity in probing effective CLFV operators associated with both single and double photon fields. In comparison to μ+→e+γ using free positive muon decays at rest, the emitted electron and photon in μ−→e−γ exhibit nonmonochromatic spectra, presenting nontrivial case. We derive the decay rate formula and demonstrate that the potential rate of the process is significant enough to motivate exploration in future muon CLFV experiments.

Published by the American Physical Society
2025
Axion minicluster halo limits from wide binary disruption
Authors: Wang Zihang , Gao Yu
Published: February 2025

Axionic dark matter can form miniclusters and minicluster halos (MCHs) from inhomogeneities in the early Universe. If MCHs are sufficiently massive, then their existence can be revealed by small-scale gravitational tidal perturbation to halolike wide binary star systems in the Galaxy. The observed population of the Milky Way’s wide-separation binaries with a≳0.1 parsec offer a sensitive test to dynamic evaporation from MCHs. Considering data from recent GAIA observations, we derive significant constraints on the MCH fraction of the Galactic dark matter halo. For several scenarios including dense MCHs and isolated minicluster models, these limits will apply to axionlike particles in the mass range ma∼10−15–10−12  eV and ma∼10−19–10−16  eV, respectively.

Published by the American Physical Society
2025
Confronting cold new early dark energy and its equation of state with updated CMB, supernovae, and BAO data
Authors: Chatrchyan Aleksandr , Niedermann Florian , Poulin Vivian , Sloth Martin S.
Published: February 2025

Cold new early dark energy (cold NEDE) addresses the Hubble tension through a triggered vacuum phase transition in the dark sector. In this paper, we constrain a phenomenological fluid model using recent cosmic microwave background likelihoods based on Planck NPIPE data alongside baryonic acoustic oscillations (BAO) and supernovae data from Pantheon+. Exploiting the enhanced constraining power of the datasets, we introduce and study an extended version of the NEDE fluid model in which the equation of state parameter wNEDE, characterizing the fluid after the phase transition, is allowed to evolve with nonvanishing derivatives dwNEDE/dlna and d2wNEDE/d(lna)2. Our results indicate that data is compatible with a rather simple time dependence that could arise from a mixture of radiation and a stiff fluid. With the updated datasets, the base and extended models still show a significant reduction of the difference of the maximum tension from 6.3σ in ΛCDM down to 3.5σ with a small simultaneous reduction of the

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tension, slightly improving over recent findings for the axionlike early dark energy model. Finally, we also provide a first test of the model against new BAO data from the dark energy spectroscopic instrument survey. Replacing the previous BAO constraints in our analysis with the new ones, the tension is further reduced to 2.6σ, reaffirming the cold NEDE model as a promising solution to the Hubble tension.

Published by the American Physical Society
2025
Gravitational wave forms for extreme mass ratio collisions from supersymmetric gauge theories
Authors: Fucito Francesco , Morales Jose Francisco , Russo Rodolfo
Published: February 2025

We study the wave form emitted by a particle moving along an arbitrary (in general open) geodesic of the Schwarzschild geometry. The mathematical problem can be phrased in terms of quantities in N=2 supersymmetric gauge theories that can be calculated by using localization and the Alday-Gaiotto-Tachikawa correspondence. In particular through this mapping, the post-Newtonian expansion of the wave form is expressed as a double instanton sum with rational coefficients that resums all tail contributions into Gamma functions and exponentials. The formulas we obtain are valid for generic values of the orbital quantum numbers ℓ and m. For ℓ=2, 3 we check explicitly that our results agree with the small mass ratio limit of the wave forms derived in the multipole post-Minkowskian and the amplitudes approaches. We show how the so-called tails and tails-of-tails contributions to the wave form arise in our approach. Finally, we derive a universal formula for the soft limit of the wave form that resums all logarithmic terms of the form ωn−1(logω)n.

Published by the American Physical Society
2025
Modulated instabilities and the
AdS2
point in dense holographic matter
Authors: Cruz Rojas Jesús , Demircik Tuna , Järvinen Matti
Published: February 2025

We investigate fluctuations of hot and dense QCD plasma by using the gauge/gravity duality. To this end, we carry out a comprehensive classification and analysis of quasinormal modes of charged black holes in the holographic V-QCD model. It turns out that the Chern-Simons term determined by the flavor anomalies of QCD is strong enough to drive a modulated instability. While such an instability is expected at high densities, we find that the unstable phase extends to surprisingly low densities and high temperatures, close to the region where data from lattice simulations are available. We also analyze the limit of small temperature which is controlled by a quantum critical AdS2 point. We study in detail the signatures of the critical point in the quasinormal mode spectrum, focusing on the interplay between the hydrodynamic modes and other modes.

Published by the American Physical Society
2025
Proposal for many-body quantum chaos detection
Authors: Das Adway Kumar , Cianci Cameron , Cabral Delmar G. A. , Zarate-Herrada David A. , Pinney Patrick , Pilatowsky-Cameo Saúl , Matsoukas-Roubeas Apollonas S. , Batista Victor S. , del Campo Adolfo , Torres-Herrera E. Jonathan , Santos Lea F.
Published: February 2025

In this work, the term “quantum chaos” refers to spectral correlations similar to those found in the random matrix theory. Quantum chaos can be diagnosed through the analysis of level statistics using, e.g., the spectral form factor, which detects both short- and long-range level correlations. The spectral form factor corresponds to the Fourier transform of the two-point spectral correlation function and exhibits a typical slope-dip-ramp-plateau structure (aka correlation hole) when the system is chaotic. We discuss how this structure could be detected through the quench dynamics of two physical quantities accessible to experimental many-body quantum systems: the survival probability and the spin autocorrelation function. The survival probability is equivalent to the spectral form factor with an additional filter. When the system is small, the dip of the correlation hole reaches sufficiently large values at times which are short enough to be detected with current experimental platforms. As the system is pushed away from chaos, the correlation hole disappears, signaling integrability or localization. We also provide a relatively shallow circuit with which the correlation hole could be detected with commercially available quantum computers.

Published by the American Physical Society
2025
Phonon Thermal Hall Effect in Mott Insulators via Skew Scattering by the Scalar Spin Chirality
Authors: Oh Taekoo , Nagaosa Naoto
Published: February 2025

Thermal transport is a crucial probe for studying excitations in insulators. In Mott insulators, the primary candidates for heat carriers are spins and phonons; which of these candidates dominates the thermal conductivity is a persistent issue. Typically, phonons dominate the longitudinal thermal conductivity while the thermal Hall effect (THE) is primarily associated with spins, requiring time-reversal symmetry breaking. The coupling between phonons and spins usually depends on spin-orbit interactions and is relatively weak. Here, we propose a new mechanism for this coupling and the associated THE: the skew scattering of phonons via spin fluctuations by the scalar spin chirality. This coupling does not require spin-orbit interactions and is ubiquitous in Mott insulators, leading to a thermal Hall angle on the order of 10−3 to 10−2. Based on this mechanism, we investigate the THE in YMnO3 with a trimerized triangular lattice where the THE beyond spins was recognized, and we predict the THE in the kagome and square lattices.

Published by the American Physical Society
2025
Benchmarking and Fidelity Response Theory of High-Fidelity Rydberg Entangling Gates
Authors: Tsai Richard Bing-Shiun , Sun Xiangkai , Shaw Adam L. , Finkelstein Ran , Endres Manuel
Published: February 2025

The fidelity of entangling operations is a key figure of merit in quantum information processing, especially in the context of quantum error correction. High-fidelity entangling gates in neutral atoms have seen remarkable advancement recently. A full understanding of error sources and their respective contributions to gate infidelity will enable the prediction of fundamental limits on quantum gates in neutral atom platforms with realistic experimental constraints. In this work, we implement the time-optimal Rydberg controlled-Z (CZ) gate, design a circuit to benchmark its fidelity, and achieve a fidelity, averaged over symmetric input states, of 0.9971(5), downward corrected for leakage error, which together with our recent work [Nature 634, 321–327 (2024)] forms a new state of the art for neutral atoms. The remaining infidelity is explained by an error model, consistent with our experimental results over a range of gate speeds, with varying contributions from different error sources. Further, we develop a fidelity response theory to efficiently predict infidelity from laser noise with nontrivial power spectral densities and derive scaling laws of infidelity with gate speed. Besides its capability of predicting gate fidelity, we also utilize the fidelity response theory to compare and optimize gate protocols, to learn laser frequency noise, and to study the noise response for quantum simulation tasks. Finally, we predict that a CZ gate fidelity of ≳0.999 is feasible with realistic experimental upgrades.

Published by the American Physical Society
2025
Governance beyond borders: exploring executive overconfidence and firm performance using meta-analysis
Authors: Agarwal Promila , Edacherian Saneesh , Karna Amit , Kaur Ashneet , Maheshwari Sudhanshu
Published: February 2025

Purpose

This study examines the complex relationship between executive overconfidence and firm performance, highlighting the moderating role of country-level factors. By conducting a meta-analysis of 116 independent effect sizes from global studies, this research aims to clarify the ambiguous effects of executive overconfidence, emphasizing the significance of national contexts.

Design/methodology/approach

Utilizing a cross-national meta-analytic framework, this study evaluates how variations in governance, board efficacy and shareholder protection across countries influence the impact of executive overconfidence on firm performance.

Findings

Results reveal that the relationship between executive overconfidence and performance is significantly shaped by country-level factors, suggesting a need to consider contextual influences alongside traditional trait-focused perspectives and underscoring the importance of contextual influences.

Practical implications

The findings suggest that organizations should incorporate national-level contextual factors in their governance structures to better manage the risks associated with executive overconfidence.

Originality/value

This study advances the literature by providing a comprehensive analysis of how country-specific variables modulate the effects of executive overconfidence on firm outcomes. It offers new insights into the role of situational factors in executive behavior, contributing to a more nuanced understanding of leadership and organizational performance.
A novel damping discrete grey model with time-polynomial term for forecasting monthly natural gas consumption
Authors: Zhao Ying , Zhang Tao , Xu Jie , Yang Jie , Wu Wen-Ze
Published: February 2025

Purpose

This study aims to design a novel seasonal discrete grey model for forecasting monthly natural gas consumption by incorporating damping accumulation and time-polynomial term.

Design/methodology/approach

Considering the principle of new information priority and nonlinear patterns in the original series of monthly natural gas consumption, we establish a novel discrete seasonal grey model by adding the damping accumulation and time-polynomial term into the existing model. In addition, the order of damping accumulation and the coefficient of time-power term can be determined by the moth flame optimization (MFO) algorithm.

Findings

The empirical cases show that the proposed model has a better prediction performance when compared with other benchmark models, including six seasonal grey models, one statistical model and one artificial intelligent model. Based on forecasts, the proposed model can be considered a promising tool for monthly natural gas consumption (NGC) in US.

Originality/value

By combining the damping accumulation and the time-polynomial term, a new discrete seasonal grey model for improving the prediction performance of the existing grey model is proposed. The properties of the proposed model are given, and the newly-designed model is initially applied to predict monthly NGC in US.
The adaptive capacity of the tourism sector to volcanic eruption and the COVID-19 pandemic: the case of Yogyakarta, Indonesia
Authors: Ningsih Reni Diah , Ariyaningsih  , Shaw Rajib
Published: February 2025

Purpose

Tourism is a vulnerable industry easily influenced by safety and security challenges such as violence, health issues and natural disasters. To quickly recover from negative impacts in the tourism sector, the industry must adapt to changes and cope with extreme conditions. In this regard, the purpose of this paper is to understand the factors influencing the tourism industry’s adaptive capacity to volcanic eruptions and the COVID-19 pandemic.

Design/methodology/approach

Using binary logistic regression, a quantitative approach was used to answer the research question regarding the adaptive capacity against the eruption and the COVID-19 pandemic. Furthermore, a semiqualitative method was used to identify the tourism industry’s coping strategy in dealing with the eruption and the COVID-19 pandemic.

Findings

According to the research findings, the tourism industry was more affected by the COVID-19 pandemic than by the eruption. In addition, various determinant factors have influenced the adaptive ability to the eruption and the COVID-19 pandemic, and this study offers successful strategies for improving adaptive capacity and enhancing resilience. Finally, this study indicates that to deal with current issues, multi-hazard risk assessments should be integrated with adaptive capacity hazard type elements to reduce future disaster risks and improve tourism business capacity.

Originality/value

The tourism industry is the most important economic pillar in developing countries. If disasters are not adequately understood, they have the potential to halt the tourism industry. However, no research has been conducted to examine the adaptive capacity of the tourism sector in disasters, especially in volcanic eruptions and the COVID-19 pandemic.
Could entrepreneurial leadership promote employees’ IWB? The roles of intrinsic motivation, creative self-efficacy and firms’ innovation climate
Authors: Alshahrani Mohammed Awad , Yaqub Muhammad Zafar , Ali Murad , El Hakimi Imane , Salam Mohammad Asif
Published: February 2025

Purpose

Building on social cognitive theory and self-determination theory, this study aims to discern the innovative work behaviors of organizational employees as the process by which they generate, develop and implement new and valuable ideas, practices, products or procedures shaped by entrepreneurial leadership by reinforcing intrinsic motivation and creative self-efficacy under the boundary condition of a firm’s innovative climate.

Design/methodology/approach

This study used partial least squares-based structural equation modeling on a sample of 203 employees of small and medium-sized enterprises operating in Saudi Arabia.

Findings

This study found that entrepreneurial leadership improves employees’ innovative work behavior by successively enhancing their intrinsic motivation and creative self-efficacy. Furthermore, the analysis confirmed that a firm’s innovative climate significantly moderates the strength of the indirect mediation effect between entrepreneurial leadership and employees’ innovative work behavior through sequential mediation.

Practical implications

The findings of this study yield substantial theoretical and practical implications resulting from a fine-grained understanding of the instrumentality of entrepreneurial leadership in fostering employees’ innovative work behavior. Effectively orchestrating these psychological mechanisms could enable entrepreneurial leaders to alleviate their behaviors.

Originality/value

This is an original study that outlines the importance of aligning entrepreneurial leadership and an innovative climate to shape intrinsic motivation and creative self-efficacy in employees’ innovative work behavior. It demonstrates how entrepreneurial leadership enhances innovative work behavior through the sequential mediation of intrinsic motivation and creative self-efficacy under the boundary condition of an innovative climate.
The effect of expatriates’ role conflict on their desire to terminate an international assignment and venture performance: comparing wholly owned subsidiaries with international joint ventures
Authors: Gehrisch Marius Gabriel , Klingenberg Ingo , Süß Stefan
Published: February 2025

Purpose

Compared to wholly owned subsidiaries (WOSs), certain international organizational forms such as international joint ventures (IJVs) often fail. Moreover, associated expatriations to these organizational forms also regularly fail, which contributes to or exacerbates the problem described above. To address this issue, this article aims to investigate the effect of expatriates’ role conflict on their desire to terminate an international assignment and on venture performance, measured as managerial satisfaction, by comparing expatriates who are delegated to an WOS with expatriates who are delegated to an IJV.

Design/methodology/approach

Drawing on role theory, a vignette-based experimental study was conducted with role conflict and organizational form as experimental variables. After conducting two pilot studies, data were gathered by means of an online questionnaire targeting organizational assigned expatriates (AE) for the main study.

Findings

The results indicate that role conflict negatively influences managerial satisfaction with venture performance, but has no effect on expatriates’ desire to terminate an international assignment and show no moderating effect of the organizational form. Additionally, we found a significant direct effect of organizational form on managerial satisfaction with venture performance. Hence, participants were less satisfied with IJVs compared to WOSs.

Originality/value

Studies in international business research lack experimental investigations. This article addresses this deficiency for the presented topic by applying a vignette-based experimental approach, thereby drawing causal inferences. Moreover, we extend role theory to the context of IJVs and contribute to organization research, as this article is the first to make a comparison between WOSs and IJVs for the context of role conflict. Fertile opportunities for future re-search are also provided.
Italian Gen Z and sustainable coastal tourism: a segmentation analysis of knowledge, attitudes and pro-environmental behaviours
Authors: Forleo Maria Bonaventura , Bredice Marilena
Published: February 2025

Purpose

Coastal and marine tourism (CMT) is facing environmental challenges that may prove critical in the near future. A shift towards sustainable approaches is required. Investigating the approach of today’s youth, who represent an important segment of the general and tourist populations, can foster this change. The aim of this study is to investigate the knowledge, opinions, attitudes and behaviour among the Italian Gen Z in relation to coastal and marine environments and the sustainability of CMT and to perform a segmentation of young people’s profiles.

Design/methodology/approach

A survey of 778 students was performed. Descriptive statistics, tests and cluster analyses were applied.

Findings

Two-thirds of the participants are convinced that tourism activities may interfere with the protection of marine and coastal environments. Likewise, they are largely convinced that the quality of these environments could affect tourism. The respondents’ environmental behaviour is mainly related to the issues of litter and single-use plastics. Gender and area of residence significantly affect the respondents’ knowledge of marine sustainability topics, some of their behavioural attitudes and their future perspectives. The educational field is significant for many phenomena. The cluster analysis detected five groups, ranging from a distant profile to one more interested in sustainable marine tourism whose members are involved and have a strong environmental attitude.

Originality/value

The study gives an original contribution to the literature on generational cohorts and young people’s perspectives on future scenarios of sustainable coastal and marine tourism.
Leading and managing inclusive entrepreneurial ecosystems
Authors: Bendickson Joshua S. , Stewart Geoffrey T. , Cowden Birton , Lanier Patricia A. , Johnson Sydnee I.
Published: February 2025

Purpose

The purpose of this article is to discuss methods for leading and managing inclusive entrepreneurial ecosystems (IEEs) that encourage inclusion and participation from underrepresented portions of their community for entrepreneurship ecosystems to represent and help all types of entrepreneurs in their region.

Design/methodology/approach

This article uses an in-depth interview method for data collection.

Findings

Our findings present challenges and opportunities in striving to have more inclusive entrepreneurial ecosystems (IEEs) by empathizing with different populations and co-creating new and novel programs to meet needs.

Practical implications

EE leaders should follow suit with entrepreneurs and utilize the customer discovery and design thinking processes to design resources and programming that reach the various needs of entrepreneurs from all backgrounds. This process should be co-created with stakeholders to allow those communities to have ownership in the final product.

Originality/value

This article takes a pracademic approach using both interviews and academic research to determine methods for fostering IEEs.