bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting tingling sensations induced by autonomous sensory meridian response (ASMR) videos based on sound texture statistics: a comparison to pleasant feelings
Authors: Terashima Hiroki , Tada Kanae , Kondo Hirohito M.
Published: July 2024

Sound serves as a potent medium for emotional well-being, with phenomena like the autonomous sensory meridian response (ASMR) showing a unique capacity for inducing relaxation and alleviating stress. This study aimed to understand how tingling sensations (and, for comparison, pleasant feelings) that such videos induce relate to acoustic features, using a broader range of ASMR videos as stimuli. The sound texture statistics and their timing predictive of tingling and pleasantness were identified through L1-regularized linear regression. Tingling was well-predicted (
r
= 0.52), predominantly by the envelope of frequencies near 5 kHz in the 1500 to 750 ms period before the response: stronger tingling was associated with a lower amplitude around the 5 kHz frequency range. This finding was further validated using an independent set of ASMR sounds. The prediction of pleasantness was more challenging (
r
= 0.26), requiring a longer effective time window, threefold that for tingling. These results enhance our understanding of how specific acoustic elements can induce tingling sensations, and how these elements differ from those that induce pleasant feelings. Our findings have potential applications in optimizing ASMR stimuli to improve quality of life and alleviate stress and anxiety, thus expanding the scope of ASMR stimulus production beyond traditional methods.

This article is part of the theme issue ‘Sensing and feeling: an integrative approach to sensory processing and emotional experience’.
Microbacterium algihabitans sp. nov., Microbacterium phycohabitans sp. nov., and Microbacterium galbum sp. nov., isolated from dried beach seaweeds
Authors: Lee Soon Dong , Yang Hong Lim , Kim In Seop
Published: July 2024

Three actinobacterial strains, KSW2-21T, KSW2-29T and KSW4-17T, were isolated from dried seaweeds collected around Gwakji Beach in Jeju, Republic of Korea. Their taxonomic positions were determined based on genomic, physiological and morphological characteristics. The isolates were Gram-positive, aerobic, non-motile, rod-shaped bacteria characterized by the following chemotaxonomic features: ornithine as the cell wall diamino acid, the N-glycolyl type of murein, MK-11 as the predominant menaquinone, polar lipids including diphosphatidylglycerol, phosphatidylglycerol, two unidentified glycolipids and four unidentified phospholipids, with anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0 as the the major fatty acids. The 16S rRNA gene phylogeny showed that the novel strains formed three distinct sublines within the genus Microbacterium. Strain KSW4-17T formed a tight cluster with the type strain of Microbacterium hydrothermale, while strains KSW2-21T and KSW2-29T occupied distinct positions between the type strains of M. hydrothermale and Microbacterium testaceum. Strains KSW4-17T and KSW2-29T showed 99.9 % rRNA gene sequence similarity to M. hydrothermale CGMCC 1.12512T, while strain KSW2-21T revealed 99.4 % 16S rRNA gene sequence similarity to the type strains of M. hydrothermale and M. testaceum. The genome sizes and genomic G+C contents of the three isolates ranged from 3.44 to 3.74 Mbp and from 70.3 to 70.8 mol%, respectively. The phylogenomic tree based on 92 core gene sequences exhibited similar topologies to the 16S rRNA gene phylogeny. The comparison of overall genomic relatedness indices, such as average nucleotide indentity and digital DNA–DNA hybridization, supported that the isolates represent three new species of the genus Microbacterium. Based on the results obtained here, Microbacterium algihabitans sp. nov. (type strain, KSW2-21T=KACC 23322T=DSM 116381T), Microbacterium phycohabitans sp. nov. (type strain KSW2-29T=KACC 22350T=NBRC 115221T) and Microbacterium galbum sp. nov. (type strain, KSW4-17T=KACC 23323T=DSM 116383T) are proposed.
Maribellus mangrovi sp. nov., an iron-reducing bacterium isolated from mangrove sediment
Authors: Wang Hongxuan , Song Xiaoxuan , Xu Zhenxing , Du Zong-Jun
Published: July 2024

A novel facultatively anaerobic and Gram-stain-negative bacterium, designated FJH33T, was isolated from mangrove sediment sampled in Zhangzhou, PR China. Cells of strain FJH33T were rod-shaped or slightly curved-shaped, with widths of 0.3–0.5 µm and lengths of 1.0–3.0 µm. Optimum growth of strain FJH33T occurred in the presence of 3 % NaCl (w/v), at 33 °C and at pH 7.0. Oxidase activity was negative, while catalase activity was positive. Its iron-reducing ability was determined. Based on 16S rRNA gene sequence similarity, strain FJH33T was most closely related to Maribellus luteus XSD2T (95.1 %), followed by Maribellus sediminis Y2-1-60T (95.0 %) and Maribellus maritimus 5E3T (94.9 %). Genome analysis of strains FJH33T and M. luteus XSD2T revealed low genome relatedness, with an average nucleotide identity value of 73.8% and a digital DNA–DNA hybridization value of 19.0%. Phylogenetic trees built from 16S rRNA genes and genome sequences showed that strain FJH33T represents a relatively independent phylogenetic lineage within the genus Maribellus. The major cellular fatty acids (≥10 %) were iso-C15 : 0 and C18 : 1
 ω9c. The sole respiratory quinone was MK-7. The polar lipids consisted of phosphatidylethanolamine, diphosphatidylcholine, diphosphatidyglycerol and one unidentified lipid. The DNA G+C content was 41.4 mol%. Based on the integrated results of phylogenetic, physiological, biochemical and chemotaxonomic characterizations, we propose that strain FJH33T represents a novel species of the genus Maribellus, for which the name Maribellus mangrovi sp. nov. is proposed. The type strain is FJH33T (=KCTC 102210T=MCCC 1H01459T).
Acutalibacter caecimuris sp. nov., Acutalibacter intestini sp. nov. and Neglectibacter caecimuris sp. nov., three novel species of the family Oscillospiraceae isolated from caecal contents of C57BL/6J mice
Authors: He Jia-Hui , Wang Chang-Yu , Abdugheni Rashidin , Ni Xue , Liu Chang , Bi Ming-Xia , Liu Shuang-Jiang
Published: July 2024

The intestines of mice are colonized by diverse, as-yet-uncultivated bacteria. In this report, we describe the isolation, culture, genotypic and phenotypic characterization, as well as taxonomic classification of three novel anaerobic bacterial strains derived from the caecal contents of C57BL/6J male mice. According to the phenotypic and genotype-based polyphasic taxonomy, we propose three novel species within the family Oscillospiraceae. They are Acutalibacter caecimuris sp. nov. (type strain M00118T=CGMCC 1.18042T=KCTC 25739T), Acutalibacter intestini sp. nov. (type strain M00204T=CGMCC 1.18044T=KCTC 25741T) and Neglectibacter caecimuris sp. nov. (type strain M00184T=CGMCC 1.18043T=KCTC 25740T).
FLASH proton reirradiation, with or without hypofractionation, mitigates chronic toxicity in the normal murine intestine, skin, and bone
Authors: Verginadis Ioannis I. , Velalopoulou Anastasia , Kim Michele M. , Kim Kyle , Paraskevaidis Ioannis , Bell Brett , Oliaei Motlagh Seyyedeh Azar , Karaj Antoneta , Banerjee Esha , Finesso Giovanni , Assenmacher Charles-Antoine , Radaelli Enrico , Lu Jiawei , Lin Yuewei , Putt Mary E. , Diffenderfer Eric S. , Guha Chandan , Qin Ling , Metz James M. , Maity Amit , Cengel Keith A. , Koumenis Constantinos , Busch Theresa M.
Published: July 2024

Background and purpose

The normal tissue sparing afforded by FLASH radiotherapy (RT) is being intensely investigated for potential clinical translation. Here, we studied the effects of FLASH proton RT (F-PRT) in the reirradiation setting, with or without hypofractionation. Chronic toxicities in three murine models of normal tissue toxicity including the intestine, skin, and bone were investigated.

Materials and methods

In studies of the intestine, single-dose irradiation was performed with 12 Gy of Standard proton RT (S-PRT), followed by a second dose of 12 Gy of F-PRT or S-PRT. Additionally, a hypofractionation scheme was applied in the reirradiation setting (3 x 6.4 Gy of F-PRT or S-PRT, given every 48 hrs). In studies of skin/bone of the murine leg, 15 Gy of S-PRT was followed by hypofractionated reirradiation with F-PRT or S-PRT (3 x 11 Gy).

Results

Compared to reirradiation with S-PRT, F-PRT reduced intestinal fibrosis and collagen deposition in the reirradiation setting and significantly increased survival rate, demonstrating its protective effects on intestinal tissues. In previously irradiated leg tissues, reirradiation with hypofractionated F-PRT created transient dermatitis that fully resolved in contrast to reirradiation with hypofractionated S-PRT. Lymphedema was also alleviated after a second course of radiation with F-PRT, along with significant reductions in the accumulation of fibrous connective tissue in the skin compared to mice reirradiated with S-PRT. The delivery of a second course of fractionated S-PRT induced tibial fractures in 83.3% of the mice, whereas only 20% of mice reirradiated with F-PRT presented with fractures.

Conclusion

These studies provide the first evidence of the sparing effects of F-PRT, in the setting of hypofractionated reirradiation. The results support FLASH as highly relevant to the reirradiation regimen where it exhibits significant potential to minimize chronic complications for patients undergoing RT.
Connectome predictive modeling of trait mindfulness
Authors: Treves Isaac N. , Kucyi Aaron , Park Madelynn , Kral Tammi R.A. , Goldberg Simon B. , Davidson Richard J. , Rosenkranz Melissa , Whitfield-Gabrieli Susan , Gabrieli John D.E.
Published: July 2024

Introduction

Trait mindfulness refers to one’s disposition or tendency to pay attention to their experiences in the present moment, in a non-judgmental and accepting way. Trait mindfulness has been robustly associated with positive mental health outcomes, but its neural underpinnings are poorly understood. Prior resting-state fMRI studies have associated trait mindfulness with within- and between-network connectivity of the default-mode (DMN), fronto-parietal (FPN), and salience networks. However, it is unclear how generalizable the findings are, how they relate to different components of trait mindfulness, and how other networks and brain areas may be involved.

Methods

To address these gaps, we conducted the largest resting-state fMRI study of trait mindfulness to-date, consisting of a pre-registered connectome predictive modeling analysis in 367 adults across three samples collected at different sites.

Results

In the model-training dataset, we did not find connections that predicted overall trait mindfulness, but we identified neural models of two mindfulness subscales,Acting with AwarenessandNon-judging. Models included both positive networks (sets of pairwise connections that positively predicted mindfulness with increasing connectivity) and negative networks, which showed the inverse relationship. TheActing with AwarenessandNon-judgingpositive network models showed distinct network representations involving FPN and DMN, respectively. The negative network models, which overlapped significantly across subscales, involved connections across the whole brain with prominent involvement of somatomotor, visual and DMN networks. Only the negative networks generalized to predict subscale scores out-of-sample, and not across both test datasets. Predictions from both models were also negatively correlated with predictions from a well-established mind-wandering connectome model.

Conclusions

We present preliminary neural evidence for a generalizable connectivity models of trait mindfulness based on specific affective and cognitive facets. However, the incomplete generalization of the models across all sites and scanners, limited stability of the models, as well as the substantial overlap between the models, underscores the difficulty of finding robust brain markers of mindfulness facets.
Spurious correlations in surface-based functional brain imaging
Authors: Jeganathan Jayson , Koussis Nikitas C , Paton Bryan , L Sina Mansour , Zalesky Andrew , Breakspear Michael
Published: July 2024

The study of functional MRI data is increasingly performed after mapping from volumetric voxels to surface vertices. Processing pipelines commonly used to achieve this mapping produce meshes with uneven vertex spacing, with closer neighbours in sulci compared to gyri. Consequently, correlations between the fMRI time series of neighbouring sulcal vertices are stronger than expected. However, the causes, extent, and impacts of this bias are not well understood or widely appreciated. We explain the origins of these biases, and usingin-silicomodels of fMRI data, illustrate how they lead to spurious results. The bias leads to leakage of anatomical cortical folding information into fMRI time series. We show that many common analyses can be affected by this “gyral bias”, including test-retest reliability, fingerprinting, functional parcellations, regional homogeneity, and brain-behaviour associations. Finally, we provide recommendations to avoid or remedy this spatial bias.
Quantifying ‘just-right’ APC inactivation for colorectal cancer initiation
Authors: Brunet Guasch Meritxell , Feeley Nathalie , Soriano Ignacio , Thorn Steve , Tomlinson Ian , Nicholson Michael D. , Antal Tibor
Published: July 2024

Dysregulation of the tumour suppressor gene Adenomatous Polyposis Coli (APC)is a canonical step in colorectal cancer development. Curiously, most colorectal tumours carry biallelic mutations that result in only partial loss of APC function, suggesting that a ‘just-right’ level of APC inactivation, and hence Wnt signalling, provides the optimal conditions for tumorigenesis. Mutational processes act variably across theAPCgene, which could contribute to the bias against complete APC inactivation. Thus the selective consequences of partial APC loss are unclear. Here we propose a mathematical model to quantify the tumorigenic effect of biallelicAPCgenotypes, controlling for somatic mutational processes. Analysing sequence data from >2500 colorectal cancers, we find thatAPCgenotypes resulting in partial protein function confer about 50 times higher probability of progressing to cancer compared to complete APC inactivation. The optimal inactivation level varies with anatomical location and additional mutations of Wnt pathway regulators. We use this context dependency to assess the regulatory effect of secondary Wnt drivers in combination with APCin vivo, and provide evidence that mutantAMER1combines withAPCgenotypes that lead to relatively low Wnt. The fitness landscape of APC inactivation is consistent across microsatellite unstable andPOLE-deficient colorectal cancers and tumours in patients with Familial Adenomatous Polyposis suggesting a general ‘just-right’ optimum, and pointing to Wnt hyperactivation as a potential cancer vulnerability.
Increasing intraspecific plant chemical diversity at plot and plant level affects arthropod communities
Authors: Ojeda-Prieto Lina , Moreno Eliecer L. , Heinen Robin , Weisser Wolfgang W.
Published: July 2024

Plant chemistry mediates interactions between plants and their environment. While intraspecific chemodiversity at the plant level is well-studied, the effects of chemodiversity at the community level on arthropod interactions need more attention. We conducted a field experiment to test how intraspecific chemodiversity affects plant-arthropod interactions. We manipulated plots ofTanacetum vulgareL., varying in chemotype richness and composition, and monitored four arthropod groups (herbivores, flower visitors, predators, and ants) over three seasons. We hypothesized that higher plot-level chemotype richness would enhance occurrence across all studied arthropod groups but have functional group-specific effects on abundance, resulting in reduced herbivore and ant abundance and increased flower visitor and predator abundance with increased chemotype richness. Using mixed models, we found that increasing plot-level chemotype richness had a limited effect on most arthropod group occurrences but led to significant changes in abundance. Herbivore abundance decreased over time, and flower visitor abundance increased, while predatory arthropods and ants remained largely unaffected. Furthermore, we found that chemotype presence within a plot showed year-to-year variation in its effects, particularly on herbivores in which positive effects turned negative over time, and on flower visitors in which the presence of specific chemotypes positively affected their abundances. Predators and ants, on the other hand, showed weaker and more variable responses to specific chemotypes. These results suggest that different arthropod groups may respond to plant chemicals through different ecological mechanisms. Our research underscores the role of plant chemical diversity in shaping insect communities and contributing to ecosystem dynamics.
The regulatory potential of transposable elements in maize
Authors: Bubb Kerry L. , Hamm Morgan O. , Tullius Thomas W. , Min Joseph K. , Ramirez-Corona Bryan , Mueth Nicholas A. , Ranchalis Jane , Mao Yizi , Bergstrom Erik J. , Vollger Mitchell R. , Trapnell Cole , Cuperus Josh T. , Stergachis Andrew B. , Queitsch Christine
Published: July 2024

The genomes of flowering plants consist largely of transposable elements (TEs), some of which modulate gene regulation and function. However, the repetitive nature of TEs and difficulty of mapping individual TEs by short-read-sequencing have hindered our understanding of their regulatory potential. We demonstrate that long-read chromatin fiber sequencing (Fiber-seq) comprehensively identifies accessible chromatin regions (ACRs) and CpG methylation across the maize genome. We uncover stereotypical ACR patterns at young TEs that degenerate with evolutionary age, resulting in TE-enhancers preferentially marked by a novel plant-specific epigenetic feature: simultaneous hyper-CpG methylation and chromatin accessibility. We show that TE ACRs are co-opted as gene promoters and that ACR-containing TEs can facilitate gene amplification. Lastly, we uncover a pervasive epigenetic signature – hypo-5mCpG methylation and diffuse chromatin accessibility – directing TEs to specific loci, including the loci that sparked McClintock’s discovery of TEs.
Reconciling ecology and evolutionary game theory or ‘When not to think cooperation’
Authors: Tarnita Corina E. , Traulsen Arne
Published: July 2024

Evolutionary game theory (EGT)—overwhelmingly employed today for the study of cooperation in a variety of systems, from microbes to cancer and from insect to human societies—started with the seminal 1973 paper by John Maynard Smith and George Price [1], in which they probed the logic of limited war in animal conflict. If fighting was essential to get access to mates and territory, then why did fights rarely lead to serious injury? Maynard Smith and Price developed game theory to show that limited war can be selected at the individual level. Owing to the explanatory potential of this first paper, and enabled by the elegant and powerful machinery of the soon-to-be-developed replicator dynamics [2, 3], EGT took off at an accelerated pace and began to shape expectations across systems and scales. But, even as it expanded its reach from animals to microbes [4–8] and from microbes to cancer [9–11], the field did not revisit a fundamental assumption of that first paper, which subsequently got weaved into the very fabric of the framework—that individual differences in reproduction are determined only by payoff from the game (i.e. in isolation, all individuals, regardless of strategy, were assumed to have identical intrinsic growth rates). Here, we argue that this original assumption substantially limits the scope of EGT. But, because it is not explicitly presented as a caveat, predictions of EGT have been empirically tested broadly across real systems, where the intrinsic growth rates are generally not equal. That has, unsurprisingly, led to puzzling findings and contentious debates [7, 12–15]. Flagging the high potential for confusion to arise from applications of EGT to empirical systems that it is not designed to study and suggesting a way forward constitute our main motivation for this work. In the process, we reestablish a dialog with ecology that can be fruitful both ways, e.g., by providing a so-far-elusive explanation for how diverse ecological communities can assemble evolutionarily.
Basal p53 maintains a distinct transcriptional program from irradiated p53 in tissue, including tumor suppressors
Authors: Zhou Royce W , Manfredi James , Silverman Lois , Parsons Ramon E.
Published: July 2024

The significance of p53 and its primary and secondary tumor suppressor programs cannot be overstated. A context- and stress-dependent transcription factor, p53 accumulates to mount its most well-characterized programs in response to a variety of stressors, most notably DNA damage. As cells and tissues never exist in a complete absence of stress, a small amount of p53 exists in cells under physiologic stress, detectable by chromatin immunoprecipitation and sequencing, termed basal p53. Recently, we and others have shown that basal p53 is sufficient to regulate tumor suppressor function. Furthermore, others have suggested the possibility that p53 accumulation in response to experimental stress may be dispensable for its tumor suppression. We previously showed basal p53 occupancy and regulation of known tumor suppressor genes, including PTEN and PHLDA3, in non-transformed breast cells, but this study was limited by experimental stress inherent to cell culture. Given the lack of global characterization of the basal p53 landscape under non-malignant physiologic stress in vivo, we utilized a multi-omics approach to define the murine basal p53 epigenome and its transcriptional program in various normal murine tissues. In this study, we observed basal p53 binding to cis regions of multiple tumor suppressor genes in different tissues, of which some showed p53-dependent regulation of their expression, including Phlda3, Bbc3, Xaf1, and itself. Furthermore, the vast majority of basal p53 target genes were not induced upon irradiation, suggesting basal p53 operates a transcriptional program that is largely distinct from its DNA damage response. Similarly, the basal p53 target gene repertoire is unique to each tissue type.
Apoptotic caspases cleave DRP1 to promote mitochondrial fusion and anti-viral immune responses
Authors: Fang Yujie , Guan Zihan , Zhu Xiangtao , Guan Zhenqiong , Li Shufen , Peng Ke
Published: July 2024

Apoptosis has been recognized as a suicidal host-defense programmed cell death pathway against invading pathogens. However, recent evidences showed that viruses can employ caspases to cleave and inactivate immune signaling molecules to facilitate infection. Whether caspases can promote anti-viral immune responses is currently unknown. Here, we demonstrated that the NSs protein of RVFV triggers activation of apoptotic caspases, which cleave the mitochondrial fission factor DRP1 resulting in mitochondrial elongation. Elongated mitochondria promote MAVS aggregation leading to enhanced anti-viral immunity. Apoptotic caspases, including caspase-3, -6, -7 and -8, cleave DRP1 at the motifs of D500FAD503and/or AEAD556, suggesting that this cleavage event may occur during infection of different viruses. Indeed, infection of H1N1, SeV and HSV-1 all triggered apoptotic caspases activation to cleave DRP1 promoting anti-viral immune responses. Compared with wild-type DRP1, introduction of caspase-resistant DRP1 strongly attenuated immune responses triggered by virus infection. These results revealed a novel mechanism through which apoptotic caspases promote anti-viral immunity by regulating mitochondrial morphodynamics.
Comparative Analysis of RT-PCR, RT-LAMP, and Antigen Testing Strategies for Effective COVID-19 Outbreak Control: A Modeling Study
Authors: Chantanasaro Tanakorn , Sararat Chayanin , Yolai Noppamas , Suttirat Pikkanet , Nawattanapaiboon Kawin , Chauvatcharin Somchai , Chadsuthi Sudarat , Modchang Charin
Published: July 2024

The COVID-19 pandemic has highlighted the crucial role of testing in mitigating disease transmission. This study comprehensively evaluates the effectiveness and cost-efficiency of various testing strategies, including daily screening, symptom-based testing, and contact-based testing, using assays such as RT-PCR, RT-LAMP, and antigen tests. Employing stochastic modeling on a contact network, we assessed the impact of these strategies on outbreak control, using COVID-19 as a case study. Our findings demonstrate that daily screening, particularly with RT-PCR and RT-LAMP, significantly reduces transmission risks but incurs higher costs. In contrast, symptom-based testing offers a more cost-effective alternative, albeit with lower efficacy in mitigating outbreaks. Notably, testing turnaround time emerges as a more critical factor than assay sensitivity in containing outbreaks. Moreover, combining symptom-based testing with contact tracing further reduces outbreak probability and scale. To provide a comprehensive analysis, we also explored the application of these strategies in scenarios where a portion of the population has acquired immunity. Our results suggest that testing all symptomatic individuals is the most effective and cost-efficient approach in the later stages of an epidemic. These findings provide valuable insights for optimizing testing strategies to tackle current and future infectious disease outbreaks effectively and efficiently. By adapting strategies based on the stage of the epidemic, population immunity, and available resources, public health authorities can design targeted interventions to protect communities while managing limited resources.
Tensor loop reduction via the Baikov representation and an auxiliary vector
Authors: Zhang Liang
Published: July 2024

In this paper, we introduce a simple and efficient approach for the general reduction of one-loop integrals. Our method employs the introduction of an auxiliary vector and the identification of the tensor structure as an auxiliary propagator. This key insight allows us to express a wide range of one-loop integrals, encompassing both tensor structures and higher poles, in the Baikov representation. By establishing an integral-by-parts relation, we derive a recursive formula that systematically solves the one-loop reduction problem, even in the presence of various degenerate cases. Our proposed strategy is characterized by its simplicity and effectiveness, offering a significant advancement in the field of one-loop calculations.

Published by the American Physical Society
2024
Smoothed asymptotics: From number theory to QFT
Authors: Padilla Antonio , Smith Robert G. C.
Published: July 2024

Inspired by the method of smoothed asymptotics developed by Terence Tao, we introduce a new ultraviolet regularization scheme for loop integrals in quantum field theory which we call η regularization. This reveals a connection between the elimination of divergences in divergent series of powers and the preservation of gauge invariance in the regularization of loop integrals in quantum field theory. In particular, we note that a method for regularizing the series of natural numbers so that it converges to minus one-twelfth inspires a regularization scheme for non-Abelian gauge theories coupled to Dirac fermions that preserves the Ward identity for the vacuum polarization tensor and other higher point functions. We also comment on a possible connection to Schwinger proper time integrals.

Published by the American Physical Society
2024
Probing the quantum nature of gravity using a Bose-Einstein condensate
Authors: Sen Soham , Gangopadhyay Sunandan
Published: July 2024

The effect of noise induced by gravitons has been investigated using a Bose-Einstein condensate. The general complex scalar field theory with a quadratic self-interaction term has been considered in the presence of a gravitational wave. The gravitational wave perturbation is then considered as a sum of discrete Fourier modes in the momentum space. Varying the action and making use of the principle of least action, one obtains two equations of motion corresponding to the gravitational perturbation and the time-dependent part of the pseudo-Goldstone boson. Coming to an operatorial representation and quantizing the phase space variables via appropriately introduced canonical commutation relations between the canonically conjugate variables corresponding to the graviton and bosonic part of the total system, one obtains a proper quantum gravity setup. Then we obtain the Bogoliubov coefficients from the solution of the time-dependent part of the pseudo-Goldstone boson and construct the covariance metric for the bosons initially being in a squeezed state. The entries of the covariance matrix now involves a stochastic contribution which results in an operatorial stochastic structure of the quantum Fisher information. Using the stochastic average of the Fisher information, we obtain a lower bound on the amplitude parameter of the gravitational wave. As the entire calculation is done at zero temperature, the bosonic system, by construction, will behave as a Bose-Einstein condensate. For a Bose-Einstein condensate with a single mode, we observe that the lower bound of the expectation value of the square of the uncertainty in the amplitude measurement does not become infinite when the total observational term approaches zero. It always has a finite value if the gravitons are initially in a squeezed state with high enough squeezing. In order to sum over all possible momentum modes, we next consider a noise term with a suitable Gaussian weight factor which decays over time. We then obtain the lower bound on the final expectation value of the square of the variance in the amplitude parameter. Because of the noise induced by the graviton, there is a minimum value of the measurement time below which it is impossible to detect any gravitational wave using a Bose-Einstein condensate. Finally, we consider interaction between the phonon modes of the Bose-Einstein condensate which results in a decoherence. We observe that the decoherence effect becomes significant for gravitons with minimal squeezing.

Published by the American Physical Society
2024
Bifurcations and nonlinear dynamics of the follower force model for active filaments
Authors: Clarke Bethany , Hwang Yongyun , Keaveny Eric E.
Published: July 2024

Biofilament-motor protein complexes are ubiquitous in biology and drive the transport of cargo vital for many fundamental life processes at the cellular level. As they move, motor proteins exert compressive forces on the filaments to which they are attached. If the filament is clamped or tethered in some way, this force leads to buckling and a subsequent range of dynamics. The follower force model, in which a single compressive force is imposed at the filament tip, is a simple filament model that is becoming widely used to describe an elastic filament, such as a microtubule, compressed by a motor protein. Depending on the force value, one can observe different states including whirling, beating, and writhing, though the bifurcations giving rise to these states are not completely understood. In this paper, we utilize techniques from computational dynamical systems to determine and characterize these bifurcations. We track emerging time-periodic branches and identify quasiperiodic states. We investigate the effect of filament slenderness on the bifurcations and, in doing so, present a comprehensive overview of the dynamics which emerge in the follower force model.

Published by the American Physical Society
2024
Network analysis of students’ conceptual understanding of mathematical expressions for probability in upper-division quantum mechanics
Authors: Riihiluoma William D. , Topdemir Zeynep , Thompson John R.
Published: July 2024

One expected outcome of physics instruction is for students to be capable of relating physical concepts to multiple mathematical representations. In quantum mechanics (QM), students are asked to work across multiple symbolic notations, including some they have not previously encountered. To investigate student understanding of the relationships between expressions used in these various notations, a survey was developed and distributed to students at six different institutions. All of the courses studied were structured as “spins-first,” in which the course begins with spin-1/2 systems and Dirac notation before transitioning to include continuous systems and wave function notation. Network analysis techniques such as community detection methods were used to investigate conceptual connections between commonly used expressions in upper-division QM courses. Our findings suggest that, for spins-first students, Dirac bras and kets share a stronger identity with vectorlike concepts than are associated with quantum state or wave function concepts. This work represents a novel way of using well-developed network analysis techniques and suggests such techniques could be used for other purposes as well.

Published by the American Physical Society
2024
Lifshitz transitions and Weyl semimetals from a topological superconductor with supercurrent flow
Authors: Cuy Fabian G. Medina , Buccheri Francesco , Dolcini Fabrizio
Published: July 2024

A current flowing through a superconductor induces a spatial modulation in its superconducting order parameter, characterized by a wave vector Q related to the total momentum of a Cooper pair. Here we investigate this phenomenon in a p-wave topological superconductor, described by a one-dimensional Kitaev model. We demonstrate that, by treating Q as an extra synthetic dimension, the current-carrying nonequilibrium steady state can be mapped into the ground state of a half-filled two-dimensional Weyl semimetal, whose Fermi surface exhibits Lifshitz transitions when varying the model parameters. Specifically, the transition from type-I to type-II Weyl phases corresponds to the emergence of a gapless p-wave superconductor, where Cooper pairs coexist with unpaired electrons and holes. Such a transition is signaled by the appearance of a sharp cusp in the Q-dependence of the supercurrent, at a critical value Q* that is robust to variations of the chemical potential μ. We determine the maximal current that the system can sustain in the topological phase, and we discuss possible implementations.

Published by the American Physical Society
2024
Coherent radiation of an electron bunch colliding with an intense laser pulse
Authors: Gelfer E. G. , Fedotov A. M. , Klimo O. , Weber S.
Published: July 2024

We study the conditions for coherent radiation of an electron bunch driven by a counterpropagating strong pulsed electromagnetic plane wave. We derive the spectrum of the coherent radiation and show that it is emitted backward with respect to the laser propagation direction and has a very narrow angular spread. We demonstrate that for a solid density plasma coherent radiation extends to frequencies up to hundreds of keV, thereby enhancing the low-frequency part of the spectrum by many orders of magnitude. Our analytical findings are tested with three-dimensional particle-in-cell simulations of an electron bunch passing through a laser pulse, clearly demonstrating how the coherence can essentially modify the observed radiation spectrum.

Published by the American Physical Society
2024
Nature of Excitons and Their Ligand-Mediated Delocalization in Nickel Dihalide Charge-Transfer Insulators
Authors: Occhialini Connor A. , Tseng Yi , Elnaggar Hebatalla , Song Qian , Blei Mark , Tongay Seth Ariel , Bisogni Valentina , de Groot Frank M. F. , Pelliciari Jonathan , Comin Riccardo
Published: July 2024

The fundamental optical excitations of correlated transition-metal compounds are typically identified with multielectronic transitions localized at the transition-metal site, such as dd transitions. In this vein, intense interest has surrounded the appearance of sharp, below-band-gap optical transitions, i.e., excitons, within the magnetic phase of correlated Ni2+ van der Waals magnets. The interplay of magnetic and charge-transfer insulating ground states in Ni2+ systems raises intriguing questions on the roles of long-range magnetic order and of metal-ligand charge transfer in the exciton nature, which inspired microscopic descriptions beyond typical dd excitations. Here we study the impact of charge transfer and magnetic order on the excitation spectrum of the nickel dihalides (NiX2, X=Cl, Br, and I) using Ni-L3 edge resonant inelastic x-ray scattering (RIXS). In all compounds, we detect sharp excitations, analogous to the recently reported excitons, and assign them to spin-singlet multiplets of octahedrally coordinated Ni2+ stabilized by intra-atomic Hund’s exchange. Additionally, we demonstrate that these excitons are dispersive using momentum-resolved RIXS. Our data evidence a ligand-mediated multiplet dispersion, which is tuned by the charge-transfer gap and independent of the presence of long-range magnetic order. This reveals the mechanisms governing nonlocal interactions of on-site dd excitations with the surrounding crystal or magnetic structure, in analogy to ground-state superexchange. These measurements thus establish the roles of magnetic order, self-doped ligand holes, and intersite-coupling mechanisms for the properties of dd excitations in charge-transfer insulators.

Published by the American Physical Society
2024
Flocking by Turning Away
Authors: Das Suchismita , Ciarchi Matteo , Zhou Ziqi , Yan Jing , Zhang Jie , Alert Ricard
Published: July 2024

Flocking, as paradigmatically exemplified by birds, is the coherent collective motion of active agents. As originally conceived, flocking emerges through alignment interactions between the agents. Here, we report that flocking can also emerge through interactions that turn agents away from each other. Combining simulations, kinetic theory, and experiments, we demonstrate this mechanism of flocking in self-propelled Janus colloids with stronger repulsion on the front than on the rear. The polar state is stable because particles achieve a compromise between turning away from left and right neighbors. Unlike for alignment interactions, the emergence of polar order from turn-away interactions requires particle repulsion. At high concentration, repulsion produces flocking Wigner crystals. Whereas repulsion often leads to motility-induced phase separation of active particles, here it combines with turn-away torques to produce flocking. Therefore, our findings bridge the classes of aligning and nonaligning active matter. Our results could help to reconcile the observations that cells can flock despite turning away from each other via contact inhibition of locomotion. Overall, our work shows that flocking is a very robust phenomenon that arises even when the orientational interactions would seem to prevent it.

Published by the American Physical Society
2024
Lifetime Reduction of Single Germanium-Vacancy Centers in Diamond via a Tunable Open Microcavity
Authors: Zifkin Rigel , Rodríguez Rosenblueth César Daniel , Janitz Erika , Fontana Yannik , Childress Lilian
Published: July 2024

Coupling between a single quantum emitter and an optical cavity presents a key capability for future quantum networking applications. Here, we explore interactions between individual germanium-vacancy (GeV) defects in diamond and an open microcavity at cryogenic temperatures. Exploiting the tunability of our microcavity system to characterize and select emitters, we observe a Purcell-effect-induced lifetime reduction of up to 4.5±0.3 and extract coherent-coupling rates up to 360±20 MHz. Our results indicate that the GeV defect has favorable optical properties for cavity coupling, with a quantum efficiency of at least 0.34±0.05 and likely much higher.

Published by the American Physical Society
2024
In situ photodeposition of ultra-small palladium particles on TiO2
Authors: Kozyr Elizaveta , Martí-Sánchez Sara , Skorynina Alina , Arbiol Jordi , Escudero Carlos , Mino Lorenzo , Bugaev Aram
Published: July 2024

In situ and operando investigation of photocatalysts plays a fundamental role in understanding the processes of active phase formation and the mechanisms of catalytic reactions, which is crucial for the rational design of more efficient materials. Using a custom-made operando photocatalytic cell, an in situ procedure to follow the formation steps of Pd/TiO2 photocatalyst by synchrotron-based X-ray absorption spectroscopy (XAS) is proposed. The procedure resulted in the formation of ∼1 nm Pd particles with a much narrower size distribution and homogeneous spreading over TiO2 support compared with the samples generated in a conventional batch reactor. The combination of in situ XAS spectroscopy with high-angle annular dark-field scanning transmission electron microscopy demonstrated the formation of single-atom Pd(0) sites on TiO2 as the initial step of the photodeposition process. Palladium hydride particles were observed for all investigated samples upon exposure to formic acid solutions.
Instrumental broadening and the radial pair distribution function with 2D detectors
Authors: Chernyshov Dmitry , Marshall Kenneth P. , North Erlend Tiberg , Fuller Chloe A. , Wragg David S.
Published: July 2024

The atomic pair distribution function (PDF) is a real-space representation of the structure of a material. Experimental PDFs are obtained using a Fourier transform from total scattering data which may or may not have Bragg diffraction peaks. The determination of Bragg peak resolution in scattering data from the fundamental physical parameters of the diffractometer used is well established, but after the Fourier transform from reciprocal to direct space, these contributions are harder to identify. Starting from an existing definition of the resolution function of large-area detectors for X-ray diffraction, this approach is expanded into direct space. The effect of instrumental parameters on PDF peak resolution is developed mathematically, then studied with modelling and comparison with experimental PDFs of LaB6 from measurements made in different-sized capillaries.
Is internationalization abroad a prerequisite for university students' intercultural competence development?
Authors: Wang Xiaoqing , Shen Yuting
Published: July 2024

Purpose

This study aims to examine how intercultural competence (IC) among university students can be enhanced through two streams of higher education internationalization: internationalization abroad and internationalization at home (IaH). By doing so, it aims to improve university students' IC through identifying which factors are more effective in fostering IC.

Design/methodology/approach

The study is not solely a literature review, but rather a conceptual exploration based on a selective review of the literature. Due to the exploratory nature of this study, we employed a thematic analysis approach to reviewing English language literature while incorporating relevant Chinese literature to ensure a more balanced representation.

Findings

We found that international students’ IC is influenced by their overseas learning experiences, which are closely related to the duration of stay, language proficiency, intercultural contact, university management and teachers and administrative support. On the other hand, domestic students’ IC has been influenced by various IaH experiences primarily within their home university campus, such as foreign language learning, international curriculum, extracurricular activities, communication between domestic and international students, integrated management of international students, the use of Internet and communication technology and so forth. Although a direct and definitive comparison is lacking, some comparative analyses suggest that IaH experiences may yield better results in enhancing the IC of domestic students.

Originality/value

This article advances the understanding of IC development. We call for further research that values the importance of IaH in the increasingly uncertain globalization and delves into comparative analysis of the effects of two streams of higher education internationalization.
On primality of Cartesian product of graphs
Authors: El Amri Nadia , Boudabbous Imed , Yaich Mouna
Published: July 2024

Purpose

The present work focuses on the primality and the Cartesian product of graphs.

Design/methodology/approach

Given a graph G, a subset M of V (G) is a module of G if, for a, b ∈ M and x ∈ V (G) \ M, xa ∈ E(G) if and only if xb ∈ E(G). A graph G with at least three vertices is prime if the empty set, the single-vertex sets and V (G) are the only modules of G.

Findings

Motivated by works obtained on “the Cartesian product of graphs” and “the primality,” this paper creates a link between the two notions.

Originality/value

In fact, we study the primality of the Cartesian product of two connected graphs minus k vertices, where k ∈ {0, 1, 2}.
Is all that glitters gold? Exploring sustainability and business ethics education in ethics-friendly environments
Authors: Seguí-Mas Elies , Tormo-Carbó Guillermina , Sigurjonsson Throstur Olaf , Arnardóttir Auður Arna
Published: July 2024

Purpose

This study aims to identify students’ perceptions of the importance and objectives of sustainability and business ethics education, considering contextual factors (ethics-friendly environments) and including the social desirability (SD) bias to strengthen data robustness and assess response truthfulness.

Design/methodology/approach

A survey was administered to 170 business students at an Icelandic university to measure their attitudes and perceptions toward sustainability and business ethics courses. Descriptive statistics, Mann–Whitney tests, χ2 tests and multivariate regression were used for the analysis.

Findings

The results show no significant differences among participants, depending on individual and organizational factors. The authors did not find significant differences in gender, age or exposure to sustainability and business ethics courses concerning social desirability bias. Contextual solid factors can explain these results.

Originality/value

This study expands on previous research by examining students’ perceptions of sustainability and business ethics education in an “ethics-friendly environment” like Iceland, a new and fertile territory for business ethics education research. These elements are crucial for further research on students’ attitudes toward sustainability and business ethics and the role of this subject in university curricula.
Tribological properties and synergistic effects of ionic liquids and silver complexes
Authors: Sun Long , Jin Chengjie , Tang Xiaodong , Cao Kexin , Wang Songquan , Hu Ningning
Published: July 2024

Purpose

The purpose of this paper is to solve the abrupt deterioration of lubricant performance in high-temperature conditions.

Design/methodology/approach

Three silver pyrazolyl methyl pyridine complexes with different morphologies were synthesized. A four-ball tribometer was used to assess the tribological characteristics as an additive for pentaerythritol oleate both independently and compound with 1-hexyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide.

Findings

The results showed that when silver complexes and ionic liquids (IL) act independently, sheet silver complex 1 and rod silver complex 2 exhibit good lubricating performance; the optimal antifriction concentration of the ILs is 0.25 Wt.%. The tribological results of the compounds additive of ILs and silver complexes indicate that the wear scar diameter of compound 1 decreased by 16.914%, the wear volume reduced by 7.44% and the lubrication effect surpassed that of the two substances individually; rod compound 2 exhibited an antagonistic effect, intensifying wear; compound 3’s lubrication effect fell between that of the two individual components.

Originality/value

The compound of sheet silver complexes and ILs effectively solves the agglomeration problem of micro/nano lubricant additives. When the interface fails, self-repair is completed, improving the stability and antiwear performance of the lubricating oil.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0128