bluuebunny/crossref_metadata_2025 huggingface dataset:
Visual neurons recognize complex image transformations
Authors: Hiramoto Masaki , Cline Hollis T.
Published: June 2024

Natural visual scenes are dominated by sequences of transforming images. Spatial visual information is thought to be processed by detection of elemental stimulus features which are recomposed into scenes. How image information is integrated over time is unclear. We explored visual information encoding in the optic tectum. Unbiased stimulus presentation shows that the majority of tectal neurons recognize image sequences. This is achieved by temporally dynamic response properties, which encode complex image transitions over several hundred milliseconds. Calcium imaging reveals that neurons that encode spatiotemporal image sequences fire in spike sequences that predict a logical diagram of spatiotemporal information processing. Furthermore, the temporal scale of visual information is tuned by experience. This study indicates how neurons recognize dynamic visual scenes that transform over time.

One-Sentence Summary

Complex visual scenes are encoded by plastic trajectories of spatiotemporal image sequences.
Unraveling CRP/cAMP-Mediated Metabolic Regulation InEscherichia coliPersister Cells
Authors: Ngo Han G. , Mohiuddin Sayed Golam , Ananda Aina , Orman Mehmet A.
Published: June 2024

A substantial gap persists in our comprehension of how bacterial metabolism undergoes rewiring during the transition to a persistent state. Also, it remains unclear which metabolic mechanisms become indispensable for persister cell survival. To address these questions, we directed our efforts towards persister cells inEscherichia colithat emerge during the late stationary phase. These cells have been recognized for their exceptional resilience and are commonly believed to be in a dormant state. Our results demonstrate that the global metabolic regulator Crp/cAMP redirects the metabolism of these antibiotic-tolerant cells from anabolism to oxidative phosphorylation. Although our data indicates that persisters exhibit a reduced metabolic rate compared to rapidly growing exponential-phase cells, their survival still relies on energy metabolism. Extensive genomic-level analyses of metabolomics, proteomics, and single-gene deletions consistently emphasize the critical role of energy metabolism, specifically the tricarboxylic acid (TCA) cycle, electron transport chain (ETC), and ATP synthase, in sustaining the viability of persisters. Altogether, this study provides much-needed clarification regarding the role of energy metabolism in antibiotic tolerance and highlights the importance of using a multipronged approach at the genomic level to obtain a broader picture of the metabolic state of persister cells.
The impact of YabG mutations onC. difficilespore germination and processing of spore substrates
Authors: Osborne Morgan S. , Brehm Joshua N. , Olivença Carmen , Cochran Alicia M. , Serrano Mónica , Henriques Adriano O. , Sorg Joseph A.
Published: June 2024

YabG is a sporulation-specific protease that is conserved among sporulating bacteria.C. difficileYabG processes cortex destined proteins preproSleC into proSleC and CspBA to CspB and CspA. YabG also affects synthesis of spore coat/exosporium proteins CotA and CdeM. In prior work that identified CspA as the co-germinant receptor, mutations inyabGwere found which altered the co-germinants required to initiate spore germination. To understand how these mutations in theyabGlocus contribute toC. difficilespore germination, we introduced these mutations into an isogenic background. Spores derived fromC. difficile yabGC207A(catalytically inactive),C. difficile yabGA46D,C. difficile yabGG37E,andC. difficile yabGP153Lstrains germinated in response to TA alone. Recombinantly expressed and purified preproSleC incubated withE. colilysate expressing wild type YabG resulted in the removal of the pre sequence from preproSleC. Interestingly, only YabGA46Dshowed any activity towards purified preproSleC. Mutation of the YabG processing site in preproSleC (R119A) led to YabG shifting its processing to R115 or R112. Finally, changes inyabGexpression under the mutant promoters were analyzed using a SNAP-tag and revealed expression differences at early and late stages of sporulation. Overall, our results support and expand upon the hypothesis that YabG is important for germination and spore assembly and, upon mutation of the processing site, can shift where it cleaves substrates.
Transport and Organization of Individual Vimentin Filaments Within Dense Networks Revealed by Single Particle Tracking and 3D FIB-SEM
Authors: Renganathan Bhuvanasundar , Moore Andrew , Yeo Wei-Hong , Petruncio Alyson , Ackerman David , Wiegel Aubrey ,   The CellMap Team, Pasolli H. Amalia , Xu C. Shan , Shtengel Gleb , Hess Harald F. , Serpinskaya Anna S , Zhang Hao F. , Lippincott-Schwartz Jennifer , Gelfand Vladimir I.
Published: June 2024

Vimentin intermediate filaments (VIFs) form complex, tight-packed networks; due to this density, traditional ensemble labeling and imaging approaches cannot accurately discern single filament behavior. To address this, we introduce a sparse vimentin-SunTag labeling strategy to unambiguously visualize individual filament dynamics. This technique confirmed known long-range dynein and kinesin transport of peripheral VIFs and uncovered extensive bidirectional VIF motion within the perinuclear vimentin network, a region we had thought too densely bundled to permit such motility. To examine the nanoscale organization of perinuclear vimentin, we acquired high-resolution electron microscopy volumes of a vitreously frozen cell and reconstructed VIFs and microtubules within a ∼50 µm3window. Of 583 VIFs identified, most were integrated into long, semi-coherent bundles that fluctuated in width and filament packing density. Unexpectedly, VIFs displayed minimal local co-alignment with microtubules, save for sporadic cross-over sites that we predict facilitate cytoskeletal crosstalk. Overall, this work demonstrates single VIF dynamics and organization in the cellular milieu for the first time

Single-particle tracking demonstrates that individual filaments in bundles of vimentin intermediate filaments are transported in the cytoplasm by motor proteins along microtubules. Furthermore, using 3D FIB-SEM the authors showed that vimentin filament bundles are loosely packed and co-aligned with microtubules.
A group B streptococcal type VII secreted LXG toxin mediates interbacterial competition and colonization of the female genital tract
Authors: Job Alyx M. , Doran Kelly S. , Spencer Brady L.
Published: June 2024

Group BStreptococcus(GBS) asymptomatically colonizes the vagina but can opportunistically ascend to the uterus and be transmitted vertically during pregnancy, resulting in neonatal pneumonia, bacteremia and meningitis. GBS is a leading etiologic agent of neonatal infection and understanding the mechanisms by which GBS persists within the polymicrobial female genital mucosa has potential to mitigate subsequent transmission and disease. Type VIIb secretion systems (T7SSb) are encoded by Firmicutes and often mediate interbacterial competition using LXG toxins that contain conserved N-termini important for secretion and variable C-terminal toxin domains that confer diverse biochemical activities. Our recent work characterized a role for the GBS T7SSb in vaginal colonization and ascending infection but the mechanisms by which the T7SSb promotes GBS persistence in this polymicrobial niche remain unknown. Herein, we investigate the GBS T7SS in interbacterial competition and GBS niche establishment in the female genital tract. We demonstrate GBS T7SS-dependent inhibition of mucosal pathobiontEnterococcus faecalisbothin vitrousing predator-prey assays andin vivoin the murine genital tract and found that a GBS LXG protein encoded within the T7SS locus (herein named groupBstreptococcalLXGToxinA) that contributes to these phenotypes. We identify BltA as a T7SS substrate that is toxic toE. coliandS. aureusupon induction of expression along with associated chaperones. Finally, we show that BltA and its chaperones contribute to GBS vaginal colonization. Altogether, these data reveal a role for a novel T7b-secreted toxin in GBS mucosal persistence and competition.

Importance

Competition between neighboring, non-kin bacteria is essential for microbial niche establishment in mucosal environments. Gram-positive bacteria encoding T7SSb have been shown to engage in competition through export of LXG-motif containing toxins, but these have not been characterized in group BStreptococcus(GBS), an opportunistic colonizer of the polymicrobial female genital tract. Here, we show a role for GBS T7SS in competition with mucosal pathobiontEnterococcus faecalis, bothin vitroandin vivo. We further find that a GBS LXG protein contributing to this antagonism is exported by the T7SS and is intracellularly toxic to other bacteria; therefore, we have named this protein groupBstreptococcalLXGToxinA(BltA). Finally, we show that BltA and its associated chaperones promote persistence within female genital tract tissuesin vivo.These data reveal previously unrecognized mechanisms by which GBS may compete with other mucosal opportunistic pathogens to persist within the female genital tract.
One for the road: Bumble bees consume pollen at flowers
Authors: Mayberry Maggie M. , Francis Jacob S. , Burrow Jenny K. , Dall Faith E. , Bowe Michelle , Leonard Anne , Campbell Parker , Russell Avery L.
Published: June 2024

Bees are the primary consumers of pollen in many ecosystems, but pollen consumption by adult bees is rarely studied, leaving a gap in our understanding of the nutritional ecology of collective foraging and pollination biology more generally. For example, while eusocial bees feed upon pollen from colony stores, whether they also consume pollen directly from flowers to meet their own needs or to assess its quality for the broader collective is unknown. We therefore captured wild bumble bee colonies (B. bimaculatusandB. griseocollis) and tested whether individual workers consumed pollen directly from flowers in a lab-based foraging assay. After confirming presence of floral pollen in worker crops (i.e., consumption at flowers), in a field setting we tested alternative hypotheses for the function of this behavior using information about the composition, abundance, and diversity of pollen found in the crops vs. pollen baskets of three species of pollen– and nectar-foraging bumble bees (Bombus bimaculatus, B. griseocollis,andB. impatiens). Consistent with the hypothesis that consuming pollen at flowers reflects sampling, total pollen quantity in crops was consistently smaller than in pollen baskets, and basket pollen tended to be a subset of that found in crops. Further, pollen foragers consumed more and different kinds of pollen than nectar foragers. Pollen consumption at flowers is thus unlikely to be purely incidental, or to substantially benefit workers nutritionally. Instead, consuming pollen directly from flowers likely allows foragers to quickly assess pollen quality before collecting it to feed the colony as whole.

SIGNIFICANCE STATEMENT

While nectar-collecting bees are classic models for the study of foraging behavior and plant-pollinator interactions, little is known about how bees assess pollen while foraging. Pollen is a critical source of protein and lipids, offered by many plant species alongside or instead of nectar. Though variation in pollen macronutrient content and secondary chemistry affect bee reproductive performance and health, whether and how foragers evaluate pollen quality is not known. We show that foraging worker bumble bees consume pollen at flowers and suggest this behavior may allow them to sample its nutritional quality. This sheds new light on the nutritional basis of plant-pollinator interactions and adds to our understanding of how bees regulate their collection of this critical resource.
TheDrosophila tyramine-beta-hydroxylasegene encodes multiple isoforms with different functions
Authors: Ruppert Manuela , Hampel Stefanie , Sambrani Nagraj , Cibik Osman , Classen Gerbera , Duenisch Andrea , Fuchs Claire , Kell Thomas , Paluri Sravya , Scholz Henrike
Published: June 2024

The Tyramine-beta−hydroxylase (Tbh) is required for octopamine synthesis. To better understand the function of Tbh in neurotransmitter synthesis, we analyzed the molecular genetic organization of theDrosophila melanogaster Tbhgene and found that theTbhgene encodes multiple transcripts. The transcripts differ in their 5’UTR, which results in proteins that differ in their size and putative phosphorylation sites, suggesting that theTbhfunction is regulated at translational and posttranslational levels. We generated a newTbhmutant –TbhDel3- using FLP/FRT recombination mutagenesis to remove the translational start site still that is present inTbhnM18mutants. TheTbhDel3mutants share ethanol tolerance and larval locomotion defects with theTbhnM18mutants. But, they differ in terms of their cellular stress response. To develop normal levels of ethanol tolerance, Tbh is required in a subset of Tbh expressing neurons in the adult brain, which was identified using a newly generatedTbh-Gal4 driver. Taking advantage of a newly generated Tbh antibody serum, we show that one Tbh isoform is expressed in a group of peptidergic Hugin-positive and noradrenergic neurons uncoupling Tbh function from octopamine synthesis. The existence of different functional Tbh isoforms impacts our understanding of the regulatory mechanisms of neurotransmitter synthesis and the function of the octopaminergic neurotransmitter system in cellular processes and the regulation of behavior.

Author Summary

Vertebrates and insects have structurally identical signaling molecules in their nervous system, such as the neurotransmitter dopamine. But, there are also neurotransmitters that are thought to only occur in the vertebrate or insect brain. Noradrenaline is one such neurotransmitter that regulates flight and fight responses in vertebrates. In insects such as the fruit flyDrosophila melanogaster, the structurally very similar neurotransmitter octopamine is considered to be an invertebrate-specific neurotransmitter that performs similar functions to noradrenaline. The functional similarities also extend to enzymes required for synthesis. Our analysis shows that the enzyme for octopamine synthesis exists in several variations and that the connection between the enzymes and the synthesized neurotransmitter may not be as simple as presumed. Exploiting molecular, behavioral and neuroanatomical studies, we show that different variants might be used in response to different environmental conditions and/or the synthesis of alternative, structurally similar neurotransmitters, such as noradrenaline. These results challenge our view on the functions of octopamine and noradrenaline in the regulation of behavior.
Inclusion, characteristics and credibility of systematic reviews in doctoral theses: A cross-sectional study of all Medical Faculties in Sweden
Authors: Ringsten M. , Färnqvist K. , Bruschettini M. , Johansson M
Published: June 2024

Objective

Systematic reviews (SRs) are essential to ensure that decisions are informed by an up-to-date and complete understanding of the relevant research evidence. Conducting SRs within a doctoral thesis can reduce redundant, harmful and unethical research, identify knowledge gaps, and help the doctoral student obtain important skills to conduct and use research. The output and learning process of SRs overlaps with the aims of doctoral programs. We aim to explore to what extent SRs are included in doctoral theses from all medical faculties in Sweden, and to describe the type, topic and assess the credibility of the reviews.

Study design and setting

Duplicate assessors independently searched local and national repositories for doctoral theses published in 2021 within all seven medical faculties in Sweden, and categorized identified reviews based on review type, topic, and credibility using AMSTAR-2.

Results

5.4% (45/852) of all doctoral theses included a review, and 1.3% (45/3461) of all included studies were reviews. Of these, two thirds (31) were SRs and the rest (14) were broader ‘big picture’ reviews. The most common topics were interventions (42%) and exposure/etiology (32%), with no reviews of diagnostic tests. The majority of the SRs had very low (71%) or low (19%) credibility, and few reached a high (7%) or moderate (3%) credibility. The most common issues were limitations with protocols, limited search strategies, and failure to account for risk of bias in drawn conclusions.

Conclusions

Few doctoral students included SRs in their theses, and the few SRs included in doctoral theses generally had a low credibility. Increasing the rate and quality of SRs in doctoral theses can help improve quality and relevance of subsequent primary research, and help students develop important skills. Actions are needed to support doctoral students to conduct high quality SRs.

What is new?

Few doctoral students included systematic reviews (SRs) in their theses

The few SRs included in doctoral theses generally had a low credibility

Increasing the rate of SRs can help improve the relevance of subsequent research

Moreover, to support development of important skills and reach educational goals

Actions are needed to support doctoral students to conduct high quality SRs
Implementation outcomes of tuberculosis digital adherence technologies: a scoping review using the RE-AIM framework
Authors: Chilala Chimweta I , Foster Nicola , Bahukudumbi Shruti , Mohamed Mona S. , Zary Miranda , Kafie Cedric , Patel Barbie , Gore Genevieve , Schwartzman Kevin , Subbaraman Ramnath , Fielding Katherine
Published: June 2024

Introduction

Globally, tuberculosis (TB) remains one of the leading infectious causes of death, with 1.3 million deaths. Digital adherence technologies (DATs) have the potential to provide person-centred care and improve outcomes. Using the RE-AIM framework, we conducted a scoping review of DAT implementations for TB treatment.

Methods

We searched eight databases for papers published between January 2000 and April 2023, using keywords for ‘tuberculosis’ and ‘digital adherence technology’. Articles meeting prespecified inclusion criteria and containing data on RE-AIM domains were included (PROSPERO-CRD42022326968). We defined ‘reach’ as comprising cellphone ownership and engagement by people with TB (PWTB) with DATs, ‘adoption’ as engagement by healthcare providers with DAT programs, ‘implementation’ as the fidelity of the DAT program implemented, and ‘maintenance’ as longer-term uptake of DATs.

Results

Of 10,313 records, 105 contributed to the synthesis. DATs included SMS, phone, 99DOTS, video-supported therapy and pillboxes. For ‘reach’, across various settings, cellphone access varied from 50-100% and 2-31% of PWTB were excluded from accessing DATs due to technology challenges. 36-100% of PWTB agreed to use a DAT. The weighted mean of DAT engagement over dose-days was 81% for SMS, 85% for phone, 61% for 99DOTS, 87% for pillbox and 82% for VST. Concerning ‘implementation’, the fidelity of DAT implementations was affected by technological issues such as cellphone coverage, DAT malfunction and provider-facing issues; including failure to initiate intensified patient management following low DAT engagement. Findings related to RE-AIM dimensions of ‘adoption’ and ‘maintenance’ were limited.

Conclusion

Our findings suggest that the ‘reach’ of DATs may be limited by a cascade of barriers, including limitations in cellphone accessibility and suboptimal sustained DAT engagement by PWTB. Video and pillbox DATs have higher levels of engagement. Implementation challenges included technological and provider-facing issues. Improving implementation outcomes may be important for TB DATs to achieve broader public health impact.
Illuminating morphogen and patterning dynamics with optogenetic control of morphogen production
Authors: Benzinger Dirk , Briscoe James
Published: June 2024

Cells use dynamic spatial and temporal cues to instruct cell fate decisions during development. Morphogens are key examples, where the concentration and duration of morphogen exposure produce distinct cell fates that drive tissue patterning. Studying the dynamics of these processes has been challenging. Here, we establish an optogenetic system for morphogen production that enables the investigation of developmental patterningin vitro. Using a tunable light-inducible gene expression system, we generate long-range Shh gradients that pattern neural progenitors into spatially distinct progenitor domains mimicking the spatial arrangement of neural progenitors found in vivo during vertebrate neural tube development. With this system, we investigate how biochemical features of Shh and the presence of morphogen-interacting proteins affect the patterning length scale. We measure tissue clearance rates, revealing that Shh has an extracellular half-life of about 1h, and we probe how the level and duration of morphogen exposure govern the acquisition and maintenance of cell fates. The rate of Shh turnover is substantially faster than the downstream gene expression dynamics, indicating that the gradient is continually renewed during patterning. Together the optogenetic approach establishes a simple experimental system for the quantitative interrogation of morphogen patterning. Controlling morphogen dynamics in a reproducible manner provides a framework to dissect the interplay between biochemical cues, the biophysics of gradient formation, and the transcriptional programmes underlying developmental patterning.
Interactions between high-intensity light and unrestricted vision in the drive for hyperopia
Authors: Biswas Sayantan , Fianza Busoy Joanna Marie , Barathi Veluchamy A. , Muralidharan Arumugam R. , Schmetterer Leopold , Kathrani Biten K. , Brennan Noel A. , Najjar Raymond P.
Published: June 2024

PURPOSE

To evaluate the impact of optical versus illuminance factors and their duration-dependency on lens-induced hyperopia (LIH) in chick eyes.

METHODS

Hyperopia was induced in one eye in chicks (10 groups, n=126) from day 1 (D1) post-hatching until D8 using +10 D lenses with fellow eyes as controls. One group (LIH) served as the control without any interventions. Remaining groups were exposed to 2, 4 or 6 hours of unrestricted vision (UnV), high intensity light (HL), or both (HL +UnV). Ocular axial length (AL), refractive error, and choroidal thickness were measured on days 1, 4, and 8. Inter-ocular difference (IOD = experimental - contralateral eye) ± SEM was used to express outcome measures.

RESULTS

By D8, LIH decreased AL (-0.42±0.03 mm) and produced hyperopic refraction (+3.48±0.32 D) and choroidal thickening (+85.81±35.23 µm) in the LIH group (all, P<0.001). Exposure to UnV reduced LIH (i.e., hyperopic refraction, axial shortening, and choroidal thickening) in a duration-dependent manner, whereas HL potentiated the development of LIH in a duration-dependent manner. When combined, UnV overpowered HL, with resultant impact on refraction and AL being close to UnV alone, except after 6 hours, when HL+UnV induced shorter AL compared to UnV alone (P=0.03).

CONCLUSION

Daily exposure to HL, UnV, and HL+UnV altered LIH in a duration-dependent manner with UnV and LIH producing competing signals. The signal generated by UnV was generally stronger than HL in combined exposure, yet longer durations of HL affected the drive for emmetropization in eyes with UnV.
Increase in ER-mitochondria contacts and mitochondrial fusion are hallmarks of mitochondrial activation during embryogenesis
Authors: Chugunova Anastasia , Keresztes Hannah , Kobylinska Roksolana , Novatchkova Maria , Lendl Thomas , Strobl Marcus , Schutzbier Michael , Dürnberger Gerhard , Imre Richard , Roitinger Elisabeth , Pasierbek Pawel , Cencerrado Alberto Moreno , Brandstetter Marlene , Köcher Thomas , Agerer Benedikt , Genger Jakob-Wendelin , Bergthaler Andreas , Pauli Andrea
Published: June 2024

Mitochondrial ATP production is essential for development, yet the mechanisms underlying the continuous increase in mitochondrial activity during embryogenesis remain elusive. Using zebrafish as a model system for vertebrate development, we comprehensively profile mitochondrial activity, morphology, metabolome, proteome and phospho-proteome as well as respiratory chain enzymatic activity. Our data show that the increase in mitochondrial activity during embryogenesis does not require mitochondrial biogenesis, is not limited by metabolic substrates at early stages, and occurs without an increase in the abundance of respiratory chain complexes or theirin vitroactivity. Our analyses pinpoint a previously unexplored increase in mitochondrial-ER association during early stages in combination with changes in mitochondrial morphology at later stages as possible contributors to the rise in mitochondrial activity during embryogenesis. Overall, our systematic profiling of the molecular and morphological changes to mitochondria during embryogenesis provides a valuable resource for further studying mitochondrial function during embryogenesis.
Roles of feedback and feed-forward networks of dopamine subsystems: insights fromDrosophilastudies
Authors: Davidson Andrew M. , Hige Toshihide
Published: June 2024

Across animal species, dopamine-operated memory systems comprise anatomically segregated, functionally diverse subsystems. Although individual subsystems could operate independently to support distinct types of memory, the logical interplay between subsystems is expected to enable more complex memory processing by allowing existing memory to influence future learning. Recent comprehensive ultrastructural analysis of theDrosophilamushroom body revealed intricate networks interconnecting the dopamine subsystems—the mushroom body compartments. Here, we review the functions of some of these connections that are beginning to be understood. Memory consolidation is mediated by two different forms of network: A recurrent feedback loop within a compartment maintains sustained dopamine activity required for consolidation, whereas feed-forward connections across compartments allow short-term memory formation in one compartment to open the gate for long-term memory formation in another compartment. Extinction and reversal of aversive memory rely on a similar feed-forward circuit motif that signals omission of punishment as a reward, which triggers plasticity that counteracts the original aversive memory trace. Finally, indirect feed-forward connections from a long-term memory compartment to short-term memory compartments mediate higher-order conditioning. Collectively, these emerging studies indicate that feedback control and hierarchical connectivity allow the dopamine subsystems to work cooperatively to support diverse and complex forms of learning.
Future avenues inDrosophilamushroom body research
Authors: Chan Ivy Chi Wai , Chen Nannan , Hernandez John , Meltzer Hagar , Park Annie , Stahl Aaron
Published: June 2024

How does the brain translate sensory information into complex behaviors? With relatively small neuronal numbers, readable behavioral outputs, and an unparalleled genetic toolkit, theDrosophilamushroom body (MB) offers an excellent model to address this question in the context of associative learning and memory. Recent technological breakthroughs, such as the freshly completed full-brain connectome, multiomics approaches, CRISPR-mediated gene editing, and machine learning techniques, led to major advancements in our understanding of the MB circuit at the molecular, structural, physiological, and functional levels. Despite significant progress in individual MB areas, the field still faces the fundamental challenge of resolving how these different levels combine and interact to ultimately control the behavior of an individual fly. In this review, we discuss various aspects of MB research, with a focus on the current knowledge gaps, and an outlook on the future methodological developments required to reach an overall view of the neurobiological basis of learning and memory.
Production of
D(*)D¯(*)
near the thresholds in
e+e−
annihilation
Authors: Salnikov S. G. , Milstein A. I.
Published: June 2024

It is shown that the nontrivial energy dependencies of DD¯, DD¯*, and D*D¯* pair production cross sections in e+e− annihilation are well described within the approach based on an account of the final-state interaction of produced particles. This statement is valid for the production of charged and neutral particles. Interaction of D(*) and D¯(*) is taken into account using the effective potential method. Its applicability is based on the fact that for near-threshold resonance the characteristic width of peak in the wave function is much larger than the interaction radius. The transition amplitudes between all three channels play an important role in the description of cross sections. These transitions are possible since all channels have the same quantum numbers JPC=1−−.

Published by the American Physical Society
2024
Parallel tempered metadynamics: Overcoming potential barriers without surfing or tunneling
Authors: Eichhorn Timo , Fuwa Gianluca , Hoelbling Christian , Varnhorst Lukas
Published: June 2024

At fine lattice spacings, Markov chain Monte Carlo simulations of QCD and other gauge theories with or without fermions are plagued by slow modes that give rise to large autocorrelation times. This can lead to simulation runs that are effectively stuck in one topological sector, a problem known as topological freezing. Here, we demonstrate that for a relevant set of parameters, metadynamics can be used to unfreeze four-dimensional SU(3) gauge theory. However, compared to local update algorithms and the Hybrid Monte Carlo algorithm, the computational overhead is significant in pure gauge theory, and the required reweighting procedure may considerably reduce the effective sample size. To deal with the latter problem, we propose modifications to the metadynamics bias potential and the combination of metadynamics with parallel tempering. We test the new algorithm in four-dimensional SU(3) gauge theory and find that it can achieve topological unfreezing without compromising the effective sample size, thereby reducing the autocorrelation times of topological observables by at least 2 orders of magnitude compared to conventional update algorithms. Additionally, we observe significantly improved scaling of autocorrelation times with the lattice spacing in two-dimensional U(1) gauge theory.

Published by the American Physical Society
2024
Lattice
B
-field correlators for heavy quarks
Authors: Altenkort Luis , de la Cruz David , Kaczmarek Olaf , Moore Guy D. , Shu Hai-Tao
Published: June 2024

We analyze the color-magnetic (or “B”) field two-point function that encodes the finite-mass correction to the heavy-quark momentum-diffusion coefficient. The simulations are done on fine isotropic lattices in the quenched approximation at 1.5Tc, using a range of gradient flow times for noise suppression and operator renormalization. The continuum extrapolation is performed at fixed flow time followed by a second extrapolation to zero flow time. Perturbative calculations to next-to-leading order of this correlation function, matching gradient-flowed correlators to MS¯, are used to resolve nontrivial renormalization issues. We perform a spectral reconstruction based on perturbative model fits to estimate the coefficient κB of the finite-mass correction to the heavy-quark momentum-diffusion coefficient. The approach we present here yields high-precision data for the correlator with all renormalization issues incorporated at next-to-leading order and is also applicable for actions with dynamical fermions.

Published by the American Physical Society
2024
Studying the phase diagram of the three-flavor Schwinger model in the presence of a chemical potential with measurement- and gate-based quantum computing
Authors: Schuster Stephan , Kühn Stefan , Funcke Lena , Hartung Tobias , Pleinert Marc-Oliver , von Zanthier Joachim , Jansen Karl
Published: June 2024

We propose an ansatz quantum circuit for the variational quantum eigensolver (VQE), suitable for exploring the phase structure of the multiflavor Schwinger model in the presence of a chemical potential. Our ansatz is capable of incorporating relevant model symmetries via constrains on the parameters, and can be implemented on circuit-based as well as measurement-based quantum devices. We show via classical simulation of the VQE that our ansatz is able to capture the phase structure of the model, and can approximate the ground state to a high level of accuracy. Moreover, we perform proof-of-principle simulations on superconducting, gate-based quantum hardware. Our results show that our approach is suitable for current gate-based quantum devices, and can be readily implemented on measurement-based quantum devices once available.

Published by the American Physical Society
2024
Enhanced X-ray free-electron laser performance with optical klystron and helical undulators
Authors: Kittel Christoph , Calvi Marco , Reiche Sven , Sammut Nicholas , Wang Guanglei , Prat Eduard
Published: June 2024

This article presents a demonstration of the improved performance of an X-ray free-electron laser (FEL) using the optical klystron mechanism and helical undulator configuration, in comparison with the common planar undulator configuration without optical klystron. The demonstration was carried out at Athos, the soft X-ray beamline of SwissFEL. Athos has variable-polarization undulators, and small magnetic chicanes placed between every two undulators to fully exploit the optical klystron. It was found that, for wavelengths of 1.24 nm and 3.10 nm, the required length to achieve FEL saturation is reduced by about 35% when using both the optical klystron and helical undulators, with each effect accounting for about half of the improvement. Moreover, it is shown that a helical undulator configuration provides a 20% to 50% higher pulse energy than planar undulators. This work represents an important step towards more compact and high-power FELs, rendering this key technology more efficient, affordable and accessible to the scientific community.
Scanning WAXS microscopy of regenerated cellulose fibers at mesoscopic resolution
Authors: Johansson Sara , Scattarella Francesco , Kalbfleisch Sebastian , Johansson Ulf , Ward Christopher , Hetherington Crispin , Sixta Herbert , Hall Stephen , Giannini Cinzia , Olsson Ulf
Published: June 2024

In this work, regenerated cellulose textile fibers, Ioncell-F, dry-wet spun with different draw ratios, have been investigated by scanning wide-angle X-ray scattering (WAXS) using a mesoscopic X-ray beam. The fibers were found to be homogeneous on the 500 nm length scale. Analysis of the azimuthal angular dependence of a crystalline Bragg spot intensity revealed a radial dependence of the degree of orientation of crystallites that was found to increase with the distance from the center of the fiber. We attribute this to radial velocity gradients during the extrusion of the spin dope and the early stage of drawing. On the other hand, the fiber crystallinity was found to be essentially homogeneous over the fiber cross section.
Determinants of organic food purchase behaviour in the European Union: a cross-country analysis guided by the theory of planned behavior
Authors: Serebrennikov Dmytro , Kallas Zein , Thorne Fiona , Ornelas Herrera Selene Ivette , McCarthy Sinéad N.
Published: June 2024

Purpose

The purpose of this study is to analyse the impact of behavioural determinants, such as consumer attitude, subjective norm, behavioural control and sustainable buying behaviour, on organic food purchase behaviour in different EU countries.

Design/methodology/approach

A structured survey of more than 5000 individuals from Germany, Netherlands, Spain, Italy and Czech Republic was conducted to elicit consumer responses regarding behavioural determinants of organic food selection. Both a structural equation modelling approach and a multinomial logit model were employed to analyse the data.

Findings

Consumer attitudes, subjective norms and behavioural control were shown to significantly influence the frequency of organic food purchasing behaviour for the whole sample and to varying degrees across each of the countries. The effect of a sustainable buying behaviour was found to be more pronounced for Germany, Netherlands and Italy than for Czech Republic and Spain.

Research limitations/implications

Analysis is based on self-reported data on frequency of organic food purchases, which might be subject to recall bias. Overestimation may arise as consumers tend to report increased purchasing due to the “desirable” qualities of organic food. We tried to ensure that the translations bore similar meanings cross country although some miscomprehension by survey respondents was a possibility.

Practical implications

To stimulate consumer demand for organic products, it is important to design policies and interventions that take into account the impact of both behavioural factors and demographic attributes on consumer decision-making across various locations. For example, market analysts and policymakers may find it useful to exploit the impact of consumer attitude towards the qualities of organics to induce sales of such food in their locations.

Originality/value

This paper combines unique survey data from five EU countries using a common model to explore and compare consumer behavioural preferences for multiple organic food products. In addition to a classic triad of behavioural factors believed to influence organic food purchases, sustainable buying behaviour as a determinant of organic purchasing behaviour was included in the analysis.
Perfectionism damages performance: shifting the dial through learning and development interventions
Authors: Kohli Kanika , Prabhu Nandan
Published: June 2024

Purpose

This article aims to explore the relationship between perfectionism and job performance to suggest opportunities for organizational learning and development.

Design/methodology/approach

The article examines and contextualizes existing research on perfectionism for organizational learning and development. This study identifies gaps and puzzles in the perfectionism-performance relationship and provides practical insights for leaders and managers.

Findings

The study's findings suggest trends in the perfectionism-job performance relationship and have practical implications for organizations. The study also proposes practical ideas, a framework for future research and interventions that organizations can use to promote excellence in the workplace.

Originality/value

This article is original in its focus on the relationship between perfectionism and job performance, and it contributes to both research and practice by discussing the academic and practical aspects of perfectionism in the workplace.
Proactive cyber fraud response: a comprehensive framework from detection to mitigation in banks
Authors: Chhabra Roy Neha , P. Sreeleakha
Published: June 2024

Purpose

This study addresses the ever-increasing cyber risks confronting the global banking sector, particularly in India, amid rapid technological advancements. The purpose of this study is to de velop an innovative cyber fraud (CF) response system that effectively controls cyber threats, prioritizes fraud, detects early warning signs (EWS) and suggests mitigation measures.

Design/methodology/approach

The methodology involves a detailed literature review on fraud identification, assessment methods, prevention techniques and a theoretical model for fraud prevention. Machine learning-based data analysis, using self-organizing maps, is used to assess the severity of CF dynamically and in real-time.

Findings

Findings reveal the multifaceted nature of CF, emphasizing the need for tailored control measures and a shift from reactive to proactive mitigation. The study introduces a paradigm shift by viewing each CF as a unique “fraud event,” incorporating EWS as a proactive intervention. This innovative approach distinguishes the study, allowing for the efficient prioritization of CFs.

Practical implications

The practical implications of such a study lie in its potential to enhance the banking sector’s resilience to cyber threats, safeguarding stability, reputation and overall risk management.

Originality/value

The originality stems from proposing a comprehensive framework that combines machine learning, EWS and a proactive mitigation model, addressing critical gaps in existing cyber security systems.
Research trends in international public sector accounting standards (IPSAS): a bibliometric analysis
Authors: Tijjani Bashir , Algarni Ahmed Ali , Al Hudithi Faisal Abdullah , Falgi Khalid Idris , Siddique Nadeem , Khan Muhammad Ajmal
Published: June 2024

Purpose

This study aims to provide quantitative information on the research trends of international public sector accounting standards (IPSAS).

Design/methodology/approach

The study used bibliometric analysis to determine the research trends in IPSAS literature. The method was applied to papers indexed in the Scopus database to analyze the growth and publication trends of the selected papers. The research team rigorously compiled a list of keywords relevant to IPSAS after consultation with the principal researcher. The study did not apply document type, year or language filter. The search query resulted in 475 documents. The study used MS Access, Excel and Biblioshiny software for the data analysis and visualization.

Findings

The acceptance and application of IPSAS by many countries and UN system organizations have led to the rise in IPSAS literature globally. The study finds the USA to be the most productive country, with Italy, Spain and the UK as second, third and fourth, respectively. Similarly, the University of Zaragoza has produced the most publications in the field, followed by the University of Salerno and Ghent University.

Practical implications

This study provides the current state of IPSAS research globally; as a result, it supports the development of policies by the users of this standards. This information can inform the development or revision of public sector accounting policies and standards.

Originality/value

To the best of the authors’ knowledge, this is the first study that provides a bibliometric analysis of the growth and publication trends of IPSAS literature. The findings in this study uncover different areas of IPSAS research productivity globally.
Antecedents and outcomes of customer over-the-top experience: a systematic literature review
Authors: Kalra Neha , Deshwal Pankaj , Gokarn Samir , Kushwah Shiksha
Published: June 2024

Purpose

The proliferation of technological advancements has facilitated unrestricted access to and customizable consumption of content for viewers. Over-the-top (OTT) services are becoming more and more popular as the number of people using video streaming services grows around the world. In this context, this study aims to identify the antecedents and outcomes of Customer over-the-top Experience (COTTE) by synthesizing the existing research.

Design/methodology/approach

This research used the systematic literature review approach to identify the antecedents and outcomes of COTTE, along with the publication schedule, theories, analytical techniques, research methodology, and geographic scope of the 47 studies identified from the Scopus and Web of Science database.

Findings

The findings elucidate various antecedents of COTTE, including user-related, social, content-related, and website/platform-related factors. Additionally, diverse outcomes, encompassing behavioural/attitudinal and company-related factors have been discussed. Furthermore, an integrated framework is presented herein, synthesizing extant research and guiding future researchers in this domain.

Originality/value

The study’s findings offer a novel perspective for service providers aiming to enhance the OTT experience for their customers. This study stands out as one of the first to comprehensively present the antecedents and consequences of COTTE.
Reporting lag in the GCC region: exploring the nexus of earnings management and IFRS transition
Authors: Kateb Ines
Published: June 2024

Purpose

The purpose of this study is to delve into the complex interplay between earnings management (EM), the International Financial Reporting Standards (IFRS) implementation and the reporting lag (RL) within the specific context of the Gulf Cooperation Council (GCC) region, with a particular emphasis on the Saudi context, offering insights into their influence on financial reporting practices.

Design/methodology/approach

Using a panel data set of 135 Saudi companies over an eight-year period, covering four years before and after the mandatory adoption of IFRS in 2017, this study investigates the Saudi financial reporting landscape. It uses interaction moderation analysis to explore variable effects and includes robustness analyses to validate the findings.

Findings

The findings reveal three key outcomes. First, they challenge conventional expectations by showing no significant impact of discretionary accruals (DACC) on RL, contrary to established accounting theories. This deviation is attributed to unique market characteristics within the GCC region, including family-owned businesses, government involvement and distinct regulations, with specific insights relevant to Saudi Arabia. Second, an unexpected positive association between IFRS adoption and RL in Saudi Arabia emerged. Several contextual factors contribute, including transition costs, compliance expenses, institutional dynamics and reconciling IFRS with local Shariah principles. Most importantly, IFRS adoption significantly reduced RL, especially for companies with high DACC levels. This highlights IFRS’s transformative role, emphasizes aligning EM with international standards for investor confidence and mitigating nonconformity risks in the GCC region’s business landscape.

Practical implications

The research findings carry significant practical implications for companies operating within the GCC region, accentuating the strategic imperative of timely financial reporting to bolster credibility, align with international standards and fortify investor confidence. Moreover, regulators and policymakers are urged to consider tailoring accounting regulations to accommodate the distinctive GCC context, thereby adeptly addressing the intricacies stemming from the interplay of EM, IFRS adoption and RL dynamics in the region.

Originality/value

This study adds to the current body of literature by highlighting the significant moderating influence of IFRS transition on the nexus between DACC and RL. It underscores the crucial role of this global accounting framework in reshaping financial reporting practices.