bluuebunny/crossref_metadata_2025 huggingface dataset:
18F-FDG PET/CT in Pediatric Immunoglobulin G4–Related Disease
Authors: Singh Karan , Bennett Olivia , Wegner Eva Alina , Marsden Amanda , Grewal Davinder Singh
Published: March 2024

A 14-year-old boy presented with severe, nonintentional weight loss, fatigue, and cough. Investigations were notable for raised inflammatory markers and significantly elevated serum immunoglobulin G4 (IgG4). 18F-FDG PET/CT was obtained for assessment of disease involvement and extent, to exclude differential diagnoses and to guide biopsy. The study demonstrated extensive FDG-avid nodal disease and multisystem organ involvement. Excisional biopsy of a right inguinal lymph node demonstrated reactive changes with numerous IgG4-positive plasma cells consistent with IgG4-related disease. He was commenced on immunosuppressive therapy with consequent weight restoration and symptom resolution.
The Efficiency of Segmental Le Fort I Surgery in Clear Aligner Therapy of Skeletal Class III Deformity: A Pilot Study
Authors: Xiao Xiufeng , Wu Zhongxing , Yeweng Sanjie
Published: March 2024

Introduction:

The purpose of this study was to investigate the efficiency of segmental Le Fort I osteotomy in clear aligner therapy of skeletal Class III deformities and to explore whether Le Fort I segmental osteotomy was effective for maxillary incisor axis correction and reduced the duration of perioperative orthodontics.

Materials and Methods:

Patients who had skeletal Class III deformities (ANB<0) treated with extraction of the maxillary first premolars, segmental Le Fort I osteotomy, and clear aligners therapy were included in this retrospective study. We measured the amount of tooth extraction space that was closed by surgery and recorded the preoperative orthodontic and total treatment duration. Lateral cephalograms were analyzed to measure changes of maxillary incisor inclination before treatment (T0), 1 week before surgery (T1), 1 week after surgery (T2), and after total orthodontic treatment (T3). Statistical analyses were performed, and the P value was set at 0.05.

Results:

The sample was composed of 15 patients aged 19 to 30 (M=22.9) years. The average preoperative orthodontic treatment duration was 16.2±5.22 mo, with 33.5 pairs of clear aligners. The gap at the extraction site decreased from 5.42±1.57 mm to 0.80±0.62 mm on average after surgery. U1-SN and U1-NA(deg) increased sparingly with preoperative decompensation, decreased in quantity after surgery, and then slightly increased with postoperative compensation (T2<T3<T0<T1; △U1-SN, △U1-NA: T1-T2, P<0.05; T0-T1 and T2-T3, P >0.05).

Conclusions:

Le Fort I segmental osteotomy assisted decompensation of the upper anterior teeth and reduced the duration of preoperative orthodontics with clear aligners.
Liver regeneration requires reciprocal release of tissue vesicles to govern rapid hepatocyte proliferation
Authors: Ying Si-Qi , Cao Yuan , Zhou Ze-Kai , Luo Xin-Yan , Zhang Xiao-Hui , Shi Ke , Qiu Ji-Yu , Xing Shu-Juan , Li Yuan-Yuan , Zhang Kai , Zheng Chen-Xi , Jin Fang , Jin Yan , Sui Bing-Dong
Published: March 2024

Background & Aims

The liver possesses a remarkable regenerative capacity involving intricate intercellular communication, the mechanisms of which remain poorly understood. Extracellular vesicles (EVs) emerge as important messengers in diverse pathophysiological conditions. However, tissue-derived, cell-specific functional EV populations in regeneration have not been robustly investigated.

Methods

Bulk and single-cell RNA sequencing analyses of the regenerating liver after partial hepatectomy (PHx), ultrastructural examinations ofin situliver tissue EVs (LT-EVs), and nanoscale and proteomic profiling of hepatocyte-derived tissue EVs (Hep-EVs) were integrated. Targeted inhibition of Hep-EV releasein vivowas performedviaAAV-mediated shRNA knockdown ofRab27a, and Hep-EVs were intravenously infused for therapeutically use. Gross, histological, and immunofluorescent examinations of livers with evaluatingin vivoandex vivohepatocyte proliferation were conducted.

Results

LT-EVs contribute to the liver regenerative process after PHx, and hepatocytes serve as the major origin of tissue EVs in the regenerating liver. Moreover, Hep-EVs play an indispensable role to orchestrate liver regeneration, which is strengthened to release with proliferative messages identified after PHx. Mechanistically, Hep-EVs from the regenerating liver reciprocally promote hepatocyte proliferation, which are hallmarked by and function based on the Cyclin dependent kinase 1 (Cdk1) activity. Importantly, replenishment of Hep-EVs from the regenerating liver holds translational promise and rescues insufficient liver regeneration.

Conclusions

Our study establishes a functional and mechanistic framework that release of regenerative Hep-EVs govern rapid hepatocyte proliferation through cell cycle control, shedding light on investigation of physiological and endogenous tissue EV populations in organ regeneration and therapy.
Medial prefrontal dopamine dynamics reflect allocation of selective attention
Authors: Melugin Patrick R. , Nolan Suzanne O. , Kandov Evelyn , Ferrara Carson F. , Farahbakhsh Zahra Z. , Siciliano Cody A.
Published: March 2024

The mesocortical dopamine system is comprised of midbrain dopamine neurons that predominantly innervate the medial prefrontal cortex (mPFC) and exert a powerful neuromodulatory influence over this region1,2. mPFC dopamine activity is thought to be critical for fundamental neurobiological processes including valence coding and decision-making3,4. Despite enduring interest in this pathway, the stimuli and conditions that engage mPFC dopamine release have remained enigmatic due to inherent limitations in conventional methods for dopamine monitoring which have prevented real-timein vivoobservation5. Here, using a fluorescent dopamine sensor enabling time-resolved recordings of cortical dopamine activity in freely behaving mice, we reveal the coding properties of this system and demonstrate that mPFC dopamine dynamics conform to a selective attention signal. Contrary to the long-standing theory that mPFC dopamine release preferentially encodes aversive and stressful events6–8, we observed robust dopamine responses to both appetitive and aversive stimuli which dissipated with increasing familiarity irrespective of stimulus intensity. We found that mPFC dopamine does not evolve as a function of learning but displays striking temporal precedence with second-to-second changes in behavioral engagement, suggesting a role in allocation of attentional resources. Systematic manipulation of attentional demand revealed that quieting of mPFC dopamine signals the allocation of attentional resources towards an expected event which, upon detection triggers a sharp dopamine transient marking the transition from decision-making to action. The proposed role of mPFC dopamine as a selective attention signal is the first model based on direct observation of time-resolved dopamine dynamics and reconciles decades of competing theories.
Subtypes of brain change in aging and their associations with cognition and Alzheimer’s disease biomarkers
Authors: Capogna Elettra , Sørensen Øystein , Watne Leiv Otto , Roe James , Strømstad Marie , Idland Ane Victoria , Halaas Nathalie Bodd , Blennow Kaj , Zetterberg Henrik , Walhovd Kristine Beate ,   the Alzheimer's Disease Neuroimaging Initiative,   the Australian Imaging Biomarkers and Lifestyle flagship study of ageing, Fjell Anders Martin , Vidal-Piñeiro Didac
Published: March 2024

Structural brain changes underly cognitive changes in older age and contribute to inter-individual variability in cognition. Here, we assessed how changes in cortical thickness, surface area, and subcortical volume, are related to cognitive change in cognitively unimpaired older adults using structural magnetic resonance imaging (MRI) data-driven clustering. Specifically, we tested (1) which brain structural changes over time predict cognitive change in older age (2) whether these are associated with core cerebrospinal fluid (CSF) Alzheimer’s disease (AD) biomarkers phosphorylated tau (p-tau) and amyloid-β (Aβ42), and (3) the degree of overlap between clusters derived from different structural features. In total 1899 cognitively healthy older adults (50 - 93 years) were followed up to 16 years with neuropsychological and structural MRI assessments, a subsample of which (n = 612) had CSF p-tau and Aβ42 measurements. We applied Monte-Carlo Reference-based Consensus clustering to identify subgroups of older adults based on structural brain change patterns over time. Four clusters for each brain feature were identified, representing the degree of longitudinal brain decline. Each brain feature provided a unique contribution to brain aging as clusters were largely independent across modalities. Cognitive change and baseline cognition were best predicted by cortical area change, whereas higher levels of p-tau and Aβ42 were associated with changes in subcortical volume. These results provide insights into the link between changes in brain morphology and cognition, which may translate to a better understanding of different aging trajectories.
Domain general frontoparietal regions show modality-dependent coding of auditory and visual rules
Authors: Jackson J. B. , Rich A. N. , Moerel D. , Teichmann L. , Duncan J. , Woolgar A.
Published: March 2024

A defining feature of human cognition is our ability to respond flexibly to what we see and hear, changing how we respond depending on our current goals. In fact, we can rapidly associate almost any input stimulus with any arbitrary behavioural response. This remarkable ability is thought to depend on a frontoparietal “multiple demand” circuit which is engaged by many types of cognitive demand and widely referred to as domain general. However, it is not clear how responses to multiple input modalities are structured within this system. Domain generality could be achieved by holding information in an abstract form that generalises over input modality, or in a modality-tagged form, which uses similar resources but produces unique codes to represent the information in each modality. We used a stimulus-response task, with conceptually identical rules in two sensory modalities (visual and auditory), to distinguish between these possibilities. Multivariate decoding of functional magnetic resonance imaging data showed that representations of visual and auditory rules recruited overlapping neural resources but were expressed in modality-tagged non-generalisable neural codes. Our data suggest that this frontoparietal system may draw on the same or similar resources to solve multiple tasks, but does not create modality-general representations of task rules, even when those rules are conceptually identical between domains.
Lateral olivocochlear neurons modulate cochlear responses to noise exposure
Authors: Sitko Austen A. , Frank Michelle M. , Romero Gabriel E. , Goodrich Lisa V.
Published: March 2024

The sense of hearing originates in the cochlea, which detects sounds across dynamic sensory environments. Like other peripheral organs, the cochlea is subjected to environmental insults, including loud, damage-inducing sounds. In response to internal and external stimuli, the central nervous system directly modulates cochlear function through olivocochlear neurons (OCNs), which are located in the brainstem and innervate the cochlear sensory epithelium. One population of OCNs, the lateral olivocochlear (LOC) neurons, target spiral ganglion neurons (SGNs), the primary sensory neurons of the ear. LOCs alter their transmitter expression for days to weeks in response to noise exposure (NE), suggesting that they are well-positioned to tune SGN excitability over long time periods in response to auditory experience. To examine how LOCs affect auditory function after NE, we characterized the transcriptional profiles of OCNs and found that LOCs exhibit transient changes in gene expression after NE, including upregulation of multiple neuropeptide-encoding genes. Next, by generating intersectional mouse lines that selectively target LOCs, we chemogenetically ablated LOC neurons and assayed auditory responses at baseline and after NE. Compared to controls, mice lacking LOCs showed stronger NE-induced functional deficits one day later and had worse auditory function after a two-week recovery period. The number of remaining presynaptic puncta at the SGN synapse with inner hair cells did not differ between control and LOC-ablated animals, suggesting that the primary role of LOCs after NE is likely not one of protection, but one of compensation, ensuring that SGN function is enhanced during periods of need.
An algorithm to detect dicrotic notch in arterial blood pressure and photoplethysmography waveforms using the iterative envelope mean method
Authors: Pal Ravi , Rudas Akos , Kim Sungsoo , Chiang Jeffrey N. , Braney Anna , Cannesson Maxime
Published: March 2024

Background and Objective

Detection of the dicrotic notch (DN) within a cardiac cycle is essential for assessment of cardiac output, calculation of pulse wave velocity, estimation of left ventricular ejection time, and supporting feature-based machine learning models for noninvasive blood pressure estimation, and hypotension, or hypertension prediction. In this study, we present a new algorithm based on the iterative envelope mean (IEM) method to detect automatically the DN in arterial blood pressure (ABP) and photoplethysmography (PPG) waveforms.

Methods

The algorithm was evaluated on both ABP and PPG waveforms from a large perioperative dataset (MLORD dataset) comprising 17,327 patients. The analysis involved a total of 1,171,288 cardiac cycles for ABP waveforms and 3,424,975 cardiac cycles for PPG waveforms. To evaluate the algorithm’s performance, the systolic phase duration (SPD) was employed, which represents the duration from the onset of the systolic phase to the DN in the cardiac cycle. Correlation plots and regression analysis were used to compare the algorithm with an established DN detection technique (second derivative). The marking of the DN temporal location was carried out by an experienced researcher using the help of the ‘find_peaks’ function from the scipy PYTHON package, serving as a reference for the evaluation. The marking was visually validated by both an engineer and an anesthesiologist. The robustness of the algorithm was evaluated as the DN was made less visually distinct across signal-to-noise ratios (SNRs) ranging from -30 dB to -5 dB in both ABP and PPG waveforms.

Results

The correlation between SPD estimated by the algorithm and that marked by the researcher is strong for both ABP (R2(87343) =.99,p<.001) and PPG (R2(86764) =.98,p<.001) waveforms. The algorithm had a lower mean error of dicrotic notch detection (s): 0.0047 (0.0029) for ABP waveforms and 0.0046 (0.0029) for PPG waveforms, compared to 0.0693 (0.0770) for ABP and 0.0968 (0.0909) for PPG waveforms for the established 2ndderivative method. The algorithm has high accuracy of DN detection for SNR of >= -9 dB for ABP waveforms and >= -12 dB for PPG waveforms indicating robust performance in detecting the DN when it is less visibly distinct.

Conclusion

Our proposed IEM-based algorithm can detect DN in both ABP and PPG waveforms with low computational cost, even in cases where it is not distinctly defined within a cardiac cycle of the waveform (‘DN-less signals’). The algorithm can potentially serve as a valuable, fast, and reliable tool for extracting features from ABP and PPG waveforms. It can be especially beneficial in medical applications where DN-based features, such as SPD, diastolic phase duration, and DN amplitude, play a significant role.
Outcomes of a Multidisciplinary Approach to Management of Mavacamten in Obstructive Hypertrophic Cardiomyopathy
Authors: Jensen Hanna , Yousif Zaid , Huynh Trina , Kraushaar Megan , Reed Marcy , Boarman Trista , Silva Enciso Jorge , Willeford Andrew
Published: March 2024

Background

Traditional treatments for obstructive hypertrophic cardiomyopathy (oHCM) include beta-blockers, calcium channel blockers, and disopyramide. Mavacamten, a novel cardiac myosin inhibitor, is a promising oHCM therapy but has practical challenges limiting its use. This study aimed to describe a clinic workflow for mavacamten management in a real-world setting, addressing challenges such as cost, drug interactions, and monitoring requirements. The focus was on reducing patient-level costs while ensuring feasibility and efficiency.

Methods

A retrospective analysis was conducted on 34 oHCM patients considered for mavacamten between May 2022 and May 2023. The clinic workflow involved cardiologist assessment, pharmacist evaluation of drug interactions, enrollment in the mavacamten REMS program, cost reduction measures, and initiation monitoring through scheduled echocardiograms. An algorithm detailing steps and tools used in this workflow is provided.

Results

Of the 34 patients, 21 (62%) were initiated on mavacamten and followed for up to 1 year on therapy. Cost assessments indicated reduced out-of-pocket expenses with assistance programs. The median time from referral to first fill was 22 days. Patients demonstrated high adherence (99.1%) measured by proportion of days covered. Echocardiogram follow-ups showed significant improvements in left ventricular outflow tract parameters with no patients having a decrease in left ventricular ejection fraction to less than 50%.

Conclusions

The described workflow effectively addressed challenges associated with mavacamten management, emphasizing roles for clinic personnel, cost reduction strategies, and structured patient monitoring. While the workflow’s specifics may need adaptation in different settings, this report provides valuable insights for clinics implementing structured mavacamten management approaches.
Designing Combinatorial Multiepitope Vaccine Candidates against Scrub Typus by a Proteome-wide Immunoinfomatics Approach
Authors: Shaw Swarna , Bagchi Arka , Ruj Debyani , Bhattacharya Sudipta Paul , Biswas Arunima , Bhattacharya Arijit
Published: March 2024

Scrub typhus (ST) is a mite-borne infection caused by the bacteriaOrientia tsutsugamushiand a major public health concern in eastern and south eastern Asia. Early diagnosis and immediate intervention with antibiotics are required to limit the severity of the infection. Prophylaxis is compromised by the absence of an effective vaccine againstO. tsutsugamushi. Development an effective vaccine is impeded due to extreme divergence of major surface antigens limiting cross-protectivity. Adopting a proteome-wide immunoinformatic approach, here, immunodominant outer membrane proteins are identified and conserved regions enriched in B-cell, Tc-cell, and Th-cell epitopes were mapped. Similarly, immunodominant stretches from salivary proteins of the vector were identified. Fifteen independent MEVs were designed by combining such segments and were analysed for physicochemical and immunological properties. Tertiary structure of the prioritized MEV was modelled, and interaction with TLR2, 4, and 5 was profiled through molecular docking and MD simulation. A glycosylation-deficient version of the MEV was also designed and analysed similarly. Both the MEVs were immune-simulated, which indicated elicitation of effective immune response.In silicocloning and expression were performed for bacterial and mammalian expression systems. Though the proteome-wide combinatorial approach with immunodominant segments demonstrated prospect, experimental validation for its efficacy against ST is warranted.
Glutamate signaling and neuroligin/neurexin adhesion play opposing roles that are mediated by major histocompatibility complex I molecules in cortical synapse formation
Authors: Sell Gabrielle L. , Barrow Stephanie L. , McAllister A. Kimberley
Published: March 2024

Although neurons release neurotransmitter before contact, the role for this release in synapse formation remains unclear. Cortical synapses do not require synaptic vesicle release for formation1-4, yet glutamate clearly regulates glutamate receptor trafficking5,6and induces spine formation7-11. Using a culture system to dissect molecular mechanisms, we found that glutamate rapidly decreases synapse density specifically in young cortical neurons in a local and calcium-dependent manner through decreasing NMDAR transport and surface expression as well as co-transport with neuroligin (NL1). Adhesion between NL1 and neurexin 1 protects against this glutamate-induced synapse loss. Major histocompatibility I (MHCI) molecules are required for the effects of glutamate in causing synapse loss through negatively regulating NL1 levels. Thus, like acetylcholine at the NMJ, glutamate acts as a dispersal signal for NMDARs and causes rapid synapse loss unless opposed by NL1-mediated trans-synaptic adhesion. Together, glutamate, MHCI and NL1 mediate a novel form of homeostatic plasticity in young neurons that induces rapid changes in NMDARs to regulate when and where nascent glutamatergic synapses are formed.
Task structure tailors the geometry of neural representations in human lateral prefrontal cortex
Authors: Bhandari Apoorva , Keglovits Haley , Badre David
Published: March 2024

How do human brains represent tasks of varying structure? The lateral prefrontal cortex (lPFC) flexibly represents task information. However, principles that shape lPFC representational geometry remain unsettled. We use fMRI and pattern analyses to reveal the structure of lPFC representational geometries as humans perform two distinct categorization tasks- one with flat, conjunctive categories and another with hierarchical, context dependent categories. We show that lPFC encodes task relevant information with task tailored geometries of intermediate dimensionality. These geometries preferentially enhance the separability of task relevant variables while encoding a subset in abstract form. Specifically, in the flat task, a global axis encodes response relevant categories abstractly, while category specific local geometries are high dimensional. In the hierarchy task, a global axis abstractly encodes the higher level context, while low dimensional, context specific local geometries compress irrelevant information and abstractly encode the relevant information. Comparing these task geometries exposes generalizable principles by which lPFC tailors representations to different tasks.
The microbiome of the lichenLobaria pulmonariavaries according to climate in Europe
Authors: Bogale Anteneh Tamirat , Braun Maria , Bernhardt Jörg , Zühlke Daniela , Schiefelbein Ulf , Bog Manuela , Scheidegger Christoph , Zengerer Veronika , Becher Dörte , Grube Martin , Riedel Katharina , Bengtsson Mia M.
Published: March 2024

TheLobaria pulmonariaholobiont comprises algal, fungal, cyanobacterial, and bacterial components. We investigatedL. pulmonaria’sbacterial microbiome in the adaptation of this ecologically sensitive lichen species to diverse climatic conditions. Our central hypothesis posited that microbiome composition and functionality aligns with continental-scale climatic parameters related to temperature and precipitation. We also tested the impact of short-term weather dynamics, sampling season, and algal/fungal genotypes on microbiome variation. Metaproteomics provided insights into compositional and functional changes within the microbiome. Climatic variables explained 41.64% of microbiome variation, surpassing the combined influence of local weather and sampling season at 31.63%. Notably, annual mean temperature and temperature seasonality emerged as significant climatic drivers. Microbiome composition correlated with algal, not fungal genotype, suggesting similar environmental recruitment for the algal partner and microbiome. Differential abundance analyses revealed distinct protein compositions in sub-atlantic lowland and alpine regions, indicating differential microbiome responses to contrasting environmental/climatic conditions. Proteins involved in oxidative and cellular stress were notably different. Our findings highlight microbiome plasticity in adapting to stable climates, with limited responsiveness to short-term fluctuations, offering new insights into climate adaptation in lichen symbiosis.
Identification of ESCRT-III like protein sequences in yeast
Authors: Brune Thomas , Kölling Ralf
Published: March 2024

Endosomal sorting complex required for transport (ESCRT-III) is a membrane remodeling complex involved in a large number of cellular processes. It appears to perform an essential function in eukaryotes, since to date no eukaryotic organism completely devoid of ESCRT-III has been found. Yet, yeast cells with a deletion of all eight known ESCRT-III genes are viable. We therefore searched for new, previously undiscovered ESCRT-III like proteins in yeast. HHPred uncovered several proteins with similarity to Snf7. The similarity was mostly restricted to theα1-α2 hairpin region of Snf7. A conserved pattern of amino acids was detected in this region. The protein encoded by ORF YPL199c strikingly resembled Snf7 in its secondary structure. Since this protein could be the ninth member of the ESCRT-III family in yeast, we called it Nbr9 (“number nine”). Nbr9 is palmitoylated and localizes to the plasma membrane. In contrast to other palmitoylated proteins, it is not associated with lipid rafts. WhenNBR9was deleted in the octuple ESCRT-III deletion background, the yeast cells were still viable. However, despite a number of experiments, we do not have evidence at present that Nbr9 is part of an alternative ESCRT-III complex.
Theoretical and simulation study of dispersive electron cooling
Authors: Zhao He , Mao Lijun , Tang Meitang , Ma Fu , Yang Xiaodong , Yang Jiancheng
Published: March 2024

In electron cooling, the transverse cooling rate is usually smaller than the longitudinal rate, especially at high energies. By introducing dispersive cooling, it is possible to redistribute the cooling rate between longitudinal and transverse planes. Theoretically, achieving dispersive electron cooling requires an ion dispersion and a transverse gradient of longitudinal friction force. The latter depends on many factors such as the relative momentum offset, transverse displacement, e-beam density distribution, and space charge effect. Therefore, several methods can be employed to achieve dispersive electron cooling based on these factors. Based on the dc electron beam, these factors and their respective impacts on the cooling rate are discussed and analyzed. For the first time, we propose a new mechanism to achieve dispersive cooling for a uniform electron beam by placing part of the ion beam outside of the electron beam. Based on a linear friction force model, we propose a simple formula to numerically estimate the cooling rate redistribution effect of these methods. The analytical results are in good agreement with Monte Carlo calculation and numerical simulation.

Published by the American Physical Society
2024
Smallness of matter effects in long-baseline muon neutrino disappearance
Authors: Denton Peter B. , Parke Stephen J.
Published: March 2024

Current long-baseline accelerator experiments, NOvA and T2K, are making excellent measurements of neutrino oscillations and the next generation of experiments, DUNE and HK, will make measurements at the O(1%) level of precision. These measurements are a combination of the appearance channel which is more challenging experimentally but depends on many oscillation parameters, and the disappearance channel which is somewhat easier and allows for precision measurements of the atmospheric mass splitting and the atmospheric mixing angle. It is widely recognized that the matter effect plays a key role in the appearance probability, yet the effect on the disappearance probability is surprisingly small for these experiments. Here we investigate both exactly how small the effect is and show that it just begins to become relevant in the high statistics regime of DUNE.

Published by the American Physical Society
2024
All orders factorization and the Coulomb problem
Authors: Hill Richard J. , Plestid Ryan
Published: March 2024

In the limit of large nuclear charge, Z≫1, or small lepton velocity, β≪1, Coulomb corrections to nuclear beta decay and related processes are enhanced as Zα/β and become large or even nonperturbative (with α the QED fine structure constant). We provide a constructive demonstration of factorization to all orders in perturbation theory for these processes and compute the all-orders hard and soft functions appearing in the factorization formula. We clarify the relationship between effective field theory amplitudes and historical treatments of beta decay in terms of a Fermi function.

Published by the American Physical Society
2024
Discovery prospects with the Dark-photons & Axion-Like particles Interferometer
Authors: De Miguel Javier , Hernández-Cabrera Juan F. , Hernández-Suárez Elvio , Joven-Álvarez Enrique , Otani Chiko , Alberto Rubiño-Martín J. ,   On behalf of the DALI Collaboration
Published: March 2024

We discuss the discovery potential of the Dark-photons & Axion-Like particles Interferometer in this paper. The apparatus, currently in a design and prototyping phase, will probe axion dark matter from the Teide Observatory, an environment protected from terrestrial microwave sources, reaching Dine-Fischler-Srednicki-Zhitnitsky-like axion sensitivity in the range 25–250  μeV of mass. The experimental approach shows a potential to probe dark sector photons of kinetic mixing strength in excess of several 10−16 and to establish new constraints to a stochastic gravitational wave background in its band. We identify different branches, including cosmology, stellar, and particle physics, where this next-generation halo-telescope may play a role in coming years.

Published by the American Physical Society
2024
GRB221009A gamma-ray events from nonstandard neutrino self-interactions
Authors: Dhuria Mansi
Published: March 2024

The flux of high-energy astrophysical neutrinos observed by the present generation of neutrino detectors has already indicated a few hints of new physics beyond the Standard Model. In this work, we show that high-energy gamma-ray observations can also be considered as a complementary probe for unveiling the source of high-energy astrophysical neutrino events and new physics. Recently, the LHAASO collaboration has reported O(5000) gamma-ray events in the energy range between 0.5–18 TeV from gamma-ray burst GRB 221009A within 2000 seconds after the initial outburst. We showed that some of the high-energy gamma rays can be produced from the interaction of astrophysical neutrinos with CMB neutrinos through nonstandard self-interaction of neutrinos mediated by light scalar bosons. The nonstandard interaction of neutrinos recently took a lot of attention in cosmology for its role in reducing Hubble tension. We have constrained the parameter space of nonstandard self-interacting neutrinos from the flux of photons observed by LHAASO and showed consistency of the same with the resulting parameter space from Hubble tension requirements and other recent constraints from laboratory/cosmology.

Published by the American Physical Society
2024
Fluctuation corrections to Lifshitz tails in disordered systems
Authors: Garcia Enrique Rozas , Hofmann Johannes
Published: March 2024

Quenched disorder in semiconductors induces localized electronic states at the band edge, which manifest as an exponential tail in the density of states. For large impurity densities, this tail takes a universal Lifshitz form that is characterized by short-ranged potential fluctuations. We provide both analytical expressions and numerical values for the Lifshitz tail of a parabolic conduction band including its exact fluctuation prefactor. Our analysis is based on a replica field integral approach, where the leading exponential scaling of the tail is determined by an instanton profile and fluctuations around the instanton determine the subleading preexponential factor. This factor contains the determinant of a fluctuation operator, and we avoid a full computation of its spectrum by using a Gel'fand-Yaglom formalism, which provides a concise general derivation of fluctuation corrections in disorder problems. We provide a revised result for the disorder band tail in two dimensions.

Published by the American Physical Society
2024
Search for Daily Modulation of MeV Dark Matter Signals with DAMIC-M
Authors: Arnquist I. , Avalos N. , Baxter D. , Bertou X. , Castelló-Mor N. , Chavarria A. E. , Cuevas-Zepeda J. , Dastgheibi-Fard A. , De Dominicis C. , Deligny O. , Duarte-Campderros J. , Estrada E. , Gadola N. , Gaïor R. , Hossbach T. , Iddir L. , Kavanagh B. J. , Kilminster B. , Lantero-Barreda A. , Lawson I. , Lee S. , Letessier-Selvon A. , Loaiza P. , Lopez-Virto A. , McGuire K. J. , Mitra P. , Munagavalasa S. , Norcini D. , Paul S. , Piers A. , Privitera P. , Robmann P. , Scorza S. , Settimo M. , Smida R. , Traina M. , Vilar R. , Warot G. , Yajur R. , Zopounidis J-P. ,   DAMIC-M Collaboration
Published: March 2024

Dark matter (DM) particles with sufficiently large cross sections may scatter as they travel through Earth’s bulk. The corresponding changes in the DM flux give rise to a characteristic daily modulation signal in detectors sensitive to DM-electron interactions. Here, we report results obtained from the first underground operation of the DAMIC-M prototype detector searching for such a signal from DM with MeV-scale mass. A model-independent analysis finds no modulation in the rate of 1  e− events with sidereal period, where a DM signal would appear. We then use these data to place exclusion limits on DM in the mass range [0.53,2.7]  MeV/c2 interacting with electrons via a dark photon mediator. Taking advantage of the time-dependent signal we improve by ∼2 orders of magnitude on our previous limit obtained from the total rate of 1  e− events, using the same dataset. This daily modulation search represents the current strongest limit on DM-electron scattering via ultralight mediators for DM masses around 1  MeV/c2.

Published by the American Physical Society
2024
Fifth Forces from QCD Axions Scale Differently
Authors: Bauer Martin , Rostagni Guillaume
Published: March 2024

We reexamine the low-energy potential for a macroscopic fifth force generated from the exchange of two axions. The shift symmetry of the linear axion interactions leads to a potential falling off as V(r)∼1/r5. We find that in the case of the QCD axion higher-order terms in the Lagrangian break the shift symmetry and lead to the dominant contribution to the potential scaling as V(r)∼1/r3. These terms are generated by the same physics responsible for the axion mass, and therefore the new contributions to the potential induce a different force for external nucleons and leptons. We demonstrate how this result affects the sensitivity of searches for new long-range forces.

Published by the American Physical Society
2024
Correlation, crossover, and broken scaling in the Abelian Manna model
Authors: Chen Letian , Huynh Hoai Nguyen , Pruessner Gunnar
Published: March 2024

The role of correlations in self-organized critical (SOC) phenomena is investigated by studying the Abelian Manna model (AMM) in two dimensions. Local correlations of the debris left behind after avalanches are destroyed by rearranging particles on the lattice between avalanches, without changing the one-point particle density. It is found that the spatial correlations are not relevant to small avalanches, while changing the scaling of the large (system-wide) ones, yielding a crossover in the model's scaling behavior. This crossover breaks the simple scaling observed in normal SOC.

Published by the American Physical Society
2024
Detecting entanglement by pure bosonic extension
Authors: Zhu Xuanran , Zhang Chao , Cao Chenfeng , Li Youning , Poon Yiu Tung , Zeng Bei
Published: March 2024

In the realm of quantum information theory, the detection and quantification of quantum entanglement stand as paramount tasks. The relative entropy of entanglement (REE) serves as a prominent measure of entanglement, with extensive applications spanning numerous related fields. The positive partial transpose (PPT) criterion, while providing an efficient method for the computation of REE, unfortunately, falls short when dealing with bound entanglement. In this study, we propose a method termed “pure bosonic extension” to enhance the practicability of k-bosonic extensions, which approximates the set of separable states from the “outside”, through a hierarchical structure. It enables efficient characterization of the set of k-bosonic extendible states, facilitating the derivation of accurate lower bounds for REE. Compared to the semi-definite programming (SDP) approach, such as the symmetric/bosonic extension function in QETLAB, our algorithm supports much larger dimensions and higher values of extension k.

Published by the American Physical Society
2024
Wave-particle correlations in multiphoton resonances of coherent light-matter interaction
Authors: Mavrogordatos Th. K.
Published: March 2024

We discuss the conditional measurement of field amplitudes by a nonclassical photon sequence in the Jaynes-Cummings (JC) model under multiphoton operation. We do so by employing a correlator of immediate experimental relevance to reveal a distinct nonclassical evolution in the spirit of Foster []. The correlator relies on the complementary nature of the pictures obtained from different unravelings of a JC source master equation. We demonstrate that direct photodetection entails a conditioned separation of timescales, a quantum beat, and a semiclassical oscillation, produced by the coherent light-matter interaction in its strong-coupling limit. We single out the quantum beat in the analytical expression for the waiting-time distribution, pertaining to the particle nature of the scattered light, and find a negative spectrum of quadrature amplitude squeezing, characteristic of its wave nature for certain operation settings. Finally, we jointly detect the dual aspects through the wave-particle correlator, showing an asymmetric regression of fluctuations to the steady state which depends on the quadrature amplitude being measured.

Published by the American Physical Society
2024
Universal responses in nonmagnetic polar metals
Authors: Jäger Fabian , Spaldin Nicola A. , Bhowal Sayantika
Published: March 2024

We demonstrate that two phenomena, the kinetic magnetoelectric effect and the nonlinear Hall effect, are universal to polar metals as a consequence of their coexisting and contraindicated polarization and metallicity. We show that measurement of the effects provides a complete characterization of the nature of the polar metal, in that the nonzero response components indicate the direction of the polar axis, and the coefficients change signs on polarization reversal and become zero in the nonpolar phase. We illustrate our findings for the case of electron-doped PbTiO3 using a combination of density functional theory and model Hamiltonian-based calculations. Our model Hamiltonian analysis provides crucial insight into the microscopic origin of the effects, showing that they originate from inversion-symmetry-breaking-induced interorbital hoppings that correlate to an asymmetric charge density quantified by odd-parity charge multipoles. Our paper both heightens the relevance of the kinetic magnetoelectric and nonlinear Hall effects, and broadens the platform for investigating and detecting odd-parity charge multipoles in polar metals.

Published by the American Physical Society
2024
First-principles simulations of scanning tunneling microscopy images exhibiting anomalous dot patterns on armchair-edged graphene nanoribbons
Authors: Li Junhuan , Inagaki Kouji , Arima Kenta
Published: March 2024

To interpret our recent scanning tunneling microscopy (STM) experiment of nanographene sheets, in which the existence of rectangularlike lattices is confirmed, we conducted first-principles calculations of both simple and wrinkled armchair-edged graphene nanoribbons (AGNRs). We focused on the origin of this unique lattice and simulated STM images in the occupied band for the above-mentioned ribbons with different widths. Combined with the band structures of AGNRs, we investigated the features of electron distribution in detail under various magnitudes of applied sample biases (−1 to −0.05 V). In contrast to the well-known hexagonal structure of graphene at a large bias of −1 V, a rectangularlike lattice emerges in the STM images of AGNRs with specific widths when they are generated solely by electronic states occupying the valence band maximum. Furthermore, we find that a wrinkle in graphene parallel to the edges in AGNR significantly affects the STM images of a neighboring flat graphene region, even when its height is only several angstroms. By comparing the partial density of states of the wrinkle with flat graphene, we discussed the role of a wrinkle in functionalizing graphene sheets.

Published by the American Physical Society
2024
Geometry-independent superfluid weight in multiorbital lattices from the generalized random phase approximation
Authors: Tam Minh , Peotta Sebastiano
Published: March 2024

The superfluid weight of a generic lattice model with attractive Hubbard interaction is computed analytically in the isolated band limit within the generalized random phase approximation. Time-reversal symmetry, spin rotational symmetry, and the uniform pairing condition are assumed. It is found that the relation obtained in Huhtinen [] between the superfluid weight in the flat band limit and the so-called minimal quantum metric is valid even at the level of the generalized random phase approximation. For an isolated, but not necessarily flat, band it is found that the correction to the superfluid weight obtained from the generalized random phase approximation Ds(1)=Ds,c(1)+Ds,g(1) is also the sum of a conventional contribution Ds,c(1) and a geometric contribution Ds,g(1), as in the case of the known mean-field result Ds(0)=Ds,c(0)+Ds,g(0), in which the geometric term Ds,g(0) is a weighted average of the quantum metric. The conventional contribution is geometry independent, that is, independent of the orbital positions, while it is possible to find a preferred, or natural, set of orbital positions such that Ds,g(1)=0. Useful analytic expressions are derived for both the natural orbital positions and the minimal quantum metric, including its extension to bands that are not necessarily flat. Finally, using some simple examples, it is argued that the natural orbital positions may lead to a more refined classification of the topological properties of the band structure.

Published by the American Physical Society
2024
Extracting many-body quantum resources within one-body reduced density matrix functional theory
Authors: Benavides-Riveros Carlos L. , Wasak Tomasz , Recati Alessio
Published: March 2024

Quantum Fisher information (QFI) is a central concept in quantum sciences used to quantify the ultimate precision limit of parameter estimation, detect quantum phase transitions, witness genuine multipartite entanglement, or probe nonlocality. Despite this widespread range of applications, computing the QFI value of quantum many-body systems is, in general, a very demanding task. Here we combine ideas from functional theories and quantum information to develop a functional framework for the QFI of fermionic and bosonic ground states. By relying upon the constrained-search approach, we demonstrate that the QFI matrix terms can universally be determined by the one-body reduced density matrix (1-RDM), thus avoiding the use of exponentially large wave functions. Furthermore, we show that QFI functionals can be determined from the universal 1-RDM functional by calculating its derivatives with respect to the coupling strengths, thus becoming the generating functional of the QFI. We showcase our approach with the Bose-Hubbard model and present exact analytical and numerical QFI functionals. Our results provide the first connection between the one-body reduced density matrix functional theory and the quantum Fisher information.

Published by the American Physical Society
2024
AlphaFold-assisted structure determination of a bacterial protein of unknown function using X-ray and electron crystallography
Authors: Miller Justin E. , Agdanowski Matthew P. , Dolinsky Joshua L. , Sawaya Michael R. , Cascio Duilio , Rodriguez Jose A. , Yeates Todd O.
Published: March 2024

Macromolecular crystallography generally requires the recovery of missing phase information from diffraction data to reconstruct an electron-density map of the crystallized molecule. Most recent structures have been solved using molecular replacement as a phasing method, requiring an a priori structure that is closely related to the target protein to serve as a search model; when no such search model exists, molecular replacement is not possible. New advances in computational machine-learning methods, however, have resulted in major advances in protein structure predictions from sequence information. Methods that generate predicted structural models of sufficient accuracy provide a powerful approach to molecular replacement. Taking advantage of these advances, AlphaFold predictions were applied to enable structure determination of a bacterial protein of unknown function (UniProtKB Q63NT7, NCBI locus BPSS0212) based on diffraction data that had evaded phasing attempts using MIR and anomalous scattering methods. Using both X-ray and micro-electron (microED) diffraction data, it was possible to solve the structure of the main fragment of the protein using a predicted model of that domain as a starting point. The use of predicted structural models importantly expands the promise of electron diffraction, where structure determination relies critically on molecular replacement.
The structure of principal-teacher conversation: Why it matters for school leadership
Authors: Adams Curt , Adigun Olajumoke Beulah
Published: March 2024

Purpose

This study addressed a relatively understudied process of school leadership: the principal-teacher conversation about instructional change. Two distinct conversation structures were examined: controlling conversation and transformative leadership conversation (TLC). Self-determination theory (SDT) was used to make the case that TLC is a better fit for instructional change than controlling conversation. Hypotheses were developed on the relationship between principal-teacher conversation and teacher trust in the principal, teacher autonomy and teacher vitality. These mental states were identified for empirical testing because of their influence on change processes.

Design/methodology/approach

The empirical study used a correlational research design with survey data. The data came from a random sample of 2,500 teachers from the population of certified teachers in a southwestern state in the USA. Useable survey responses were obtained from 1,615 teachers, for a response rate of 65 percent. Teachers in the sample averaged 15 years of teaching experience, with 7 years in their current school. Around 81% of teachers identified as female and 18 percent as male and 79% of teachers listed a racial identification as white. Hypotheses were tested in a path model using AMOS 28.0 with robust maximum likelihood (MLR).

Findings

As hypothesized, TLC had moderate to strong positive relationships with teacher trust in the principal, teacher autonomy and teacher vitality. Controlling conversation had small, negative relationships with teacher trust in the principal and teacher autonomy. Controlling conversation was not related to teacher vitality in the path analysis. Compared with controlling conversation, TLC had stronger relationships with teacher mental states.

Originality/value

The results of this study begin to reveal useful evidence on the inherent social-psychological mechanisms active in principal-teacher conversations. With results indicating that conversation structure has consequences for positive teacher mental states, the study directs attention to a ubiquitous yet understudied leadership process.