bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcomes of transcatheter aortic valve replacement in patients with cardiogenic shock
Authors: Goel Kashish , Shah Pinak , Jones Brandon M , Korngold Ethan , Bhardwaj Anju , Kar Biswajit , Barker Colin , Szerlip Molly , Smalling Richard , Dhoble Abhijeet
Published: June 2023

Aims

The safety and efficacy of transcatheter aortic valve replacement (TAVR) with contemporary balloon expandable transcatheter valves in patients with cardiogenic shock (CS) remain largely unknown. In this study, the TAVRs performed for CS between June 2015 and September 2022 using SAPIEN 3 and SAPIEN 3 Ultra bioprosthesis from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry were analysed.

Methods and results

CS was defined as: (i) coding of CS within 24 h on Transcatheter Valve Therapy Registry form; and/or (ii) pre-procedural use of inotropes or mechanical circulatory support devices and/or (iii) cardiac arrest within 24 h prior to TAVR. The control group was comprised of all the other patients undergoing TAVR. Baseline characteristics, all-cause mortality, and major complications at 30-day and 1-year outcomes were reported. Landmark analysis was performed at 30 days post-TAVR. Cox-proportional multivariable analysis was performed to determine the predictors of all-cause mortality at 1 year. A total of 309 505 patients underwent TAVR with balloon-expandable valves during the study period. Of these, 5006 patients presented with CS prior to TAVR (1.6%). The mean Society of Thoracic Surgeons score was 10.76 ± 10.4. The valve was successfully implanted in 97.9% of patients. Technical success according to Valve Academic Research Consortium-3 criteria was 94.5%. In a propensity-matched analysis, CS was associated with higher in-hospital (9.9% vs. 2.7%), 30-day (12.9% vs. 4.9%), and 1-year (29.7% vs. 22.6%) mortality compared to the patients undergoing TAVR without CS. In the landmark analysis after 30 days, the risk of 1-year mortality was similar between the two groups [hazard ratio (HR) 1.07, 95% confidence interval (CI) 0.95–1.21]. Patients who were alive at 1 year noted significant improvements in functional class (Class I/II 89%) and quality of life (ΔKCCQ score +50). In the multivariable analysis, older age (HR 1.02, 95% CI 1.02–1.03), peripheral artery disease (HR 1.25, 95% CI 1.06–1.47), prior implantation of an implantable cardioverter-defibrillator (HR 1.37, 95% CI 1.07–1.77), patients on dialysis (HR 2.07, 95% CI 1.69–2.53), immunocompromised status (HR 1.33, 95% CI 1.05–1.69), New York Heart Association class III/IV symptoms (HR 1.50, 95% CI 1.06–2.12), lower aortic valve mean gradient, lower albumin levels, lower haemoglobin levels, and lower Kansas City Cardiomyopathy Questionnaire scores were independently associated with 1-year mortality.

Conclusion

This large observational real-world study demonstrates that the TAVR is a safe and effective treatment for aortic stenosis patients presenting with CS. Patients who survived the first 30 days after TAVR had similar mortality rates to those who were not in CS.
Cost-effectiveness of an antibacterial envelope for infection prevention in patients undergoing cardiac resynchronization therapy reoperations in Denmark
Authors: Frausing Maria Hee Jung Park , Johansen Jens Brock , Afonso Daniela , Jørgensen Ole Dan , Olsen Thomas , Gerdes Christian , Johansen Mette Lundsby , Wolff Claudia , Mealing Stuart , Nielsen Jens Cosedis , Kronborg Mads Brix
Published: June 2023

Aims

Use of an absorbable antibacterial envelope during implantation prevents cardiac implantable electronic device infections in patients with a moderate-to-high infection risk. Previous studies demonstrated that an envelope is cost-effective in high-risk patients within German, Italian, and English healthcare systems, but these analyses were based on limited data and may not be generalizable to other healthcare settings.

Methods and results

A previously published decision-tree-based cost-effectiveness model was used to compare the costs per quality-adjusted life year (QALY) associated with adjunctive use of an antibacterial envelope for infection prevention compared to standard-of-care intravenous antibiotics. The model was adapted using data from a Danish observational two-centre cohort study that investigated infection-risk patients undergoing cardiac resynchronization therapy (CRT) reoperations with and without an antibacterial envelope (n = 1943). We assumed a cost-effectiveness threshold of €34 125/QALY gained, based on the upper threshold used by the National Institute for Health and Care Excellence (£30 000). An antibacterial envelope was associated with an incremental cost-effectiveness ratio (ICER) of €12 022 per QALY in patients undergoing CRT reoperations, thus indicating that the envelope is cost-effective when compared with standard of care. A separate analysis stratified by device type showed ICERS of €6227 (CRT defibrillator) and €29 177 (CRT pacemaker) per QALY gained.

Conclusions

Cost-effectiveness ratios were favourable for patients undergoing CRT reoperations in the Danish healthcare system, and thus are in line with previous studies. Results from this study can contribute to making the technology available to Danish patients and align preventive efforts in the pacemaker and ICD area.
Ostial vs. wide area circumferential ablation guided by the Ablation Index in paroxysmal atrial fibrillation
Authors: Sousa Pedro A , Barra Sérgio , Saleiro Carolina , Khoueiry Ziad , Adão Luís , Primo João , Lagrange Philippe , Lebreiro Ana , Fonseca Paulo , Pereira Mariana , Puga Luís , Oliveiros Bárbara , Elvas Luís , Gonçalves Lino
Published: June 2023

Aims

Pulmonary vein isolation (PVI) guided by the Ablation Index (AI) has shown high acute and mid-term efficacy in the treatment of paroxysmal atrial fibrillation (AF). Previous data before the AI-era had suggested that wide-area circumferential ablation (WACA) was preferable to ostial ablation. However, with the use of AI, we hypothesize that ostial circumferential ablation is non-inferior to WACA and can improve outcomes in paroxysmal AF.

Methods and results

Prospective, multicentre, non-randomized, non-inferiority study of consecutive patients were referred for paroxysmal AF ablation from January 2020 to September 2021. All procedures were performed using the AI software, and patients were separated into two different groups: WACA vs. ostial circumferential ablation. Acute reconnection, procedural data, and 1-year arrhythmia recurrence were assessed. During the enrolment period, 162 patients (64% males, mean age of 60 ± 11 years) fulfilled the study inclusion criteria—81 patients [304 pulmonary vein (PV)] in the WACA group and 81 patients (301 PV) in the ostial group. Acute PV reconnection was identified in 7.9% [95% confidence interval (CI), 4.9–11.1%] of PVs in the WACA group compared with 3.3% (95% CI, 1.8–6.1%) of PVs in the ostial group [P < 0.001 for non-inferiority; adjusted odds ratio 0.51 (95% CI, 0.23–0.83), P = 0.05]. Patients in the WACA group had longer ablation (35 vs. 29 min, P = 0.001) and procedure (121 vs. 102 min, P < 0.001) times. No significant difference in arrhythmia recurrence was seen at 1-year of follow-up [11.1% in WACA vs. 9.9% in ostial, hazard ratio 1.13 (95% CI, 0.44–1.94), P = 0.80 for superiority].

Conclusion

In paroxysmal AF patients treated with tailored AI-guided PVI, ostial circumferential ablation is not inferior to WACA with regard to acute PV reconnection, while allowing quicker procedures with less ablation time.
Platelet-localized ST6Gal1 does not impact IgG sialylation
Authors: Glendenning Leandre M , Zhou Julie Y , Kukan Emily N , Gao Chao , Cummings Richard D , Joshi Smita , Whiteheart Sidney W , Cobb Brian A
Published: June 2023

The IgG antibody class forms an important basis of the humoral immune response, conferring reciprocal protection from both pathogens and autoimmunity. IgG function is determined by the IgG subclass, as defined by the heavy chain, as well as the glycan composition at N297, the conserved site of N-glycosylation within the Fc domain. For example, lack of core fucose promotes increased antibody-dependent cellular cytotoxicity, whereas α2,6-linked sialylation by the enzyme ST6Gal1 helps to drive immune quiescence. Despite the immunological significance of these carbohydrates, little is known about how IgG glycan composition is regulated. We previously reported that mice with ST6Gal1-deficient B cells have unaltered IgG sialylation. Likewise, ST6Gal1 released into the plasma by hepatocytes does not significantly impact overall IgG sialylation. Since IgG and ST6Gal1 have independently been shown to exist in platelet granules, it was possible that platelet granules could serve as a B cell-extrinsic site for IgG sialylation. To address this hypothesis, we used a platelet factor 4 (Pf4)-Cre mouse to delete ST6Gal1 in megakaryocytes and platelets alone or in combination with an albumin-Cre mouse to also remove it from hepatocytes and the plasma. The resulting mouse strains were viable and had no overt pathological phenotype. We also found that despite targeted ablation of ST6Gal1, no change in IgG sialylation was apparent. Together with our prior findings, we can conclude that in mice, neither B cells, the plasma, nor platelets have a substantial role in homeostatic IgG sialylation.
Communication costs in science: evidence from the National Science Foundation Network
Authors: Goldstein Ezra G
Published: June 2023

How do communication costs affect the creation of scientific output? This study examines changes in scientific output and citation patterns following an institution’s connection to the National Science Foundation Network (NSFNET), an early version of the Internet. Established in 1985 to connect five NSF-sponsored supercomputers, the NSFNET national internet backbone quickly expanded to universities across the United States by linking existing and newly formed, wide-area regional computer networks. I estimate the effect of connection to the national internet backbone on citations per paper by exploiting plausibly exogenous variation in the connection times of the regional NSFNET networks. Following connection to the national NSFNET, average citations per paper increase by over 10% relative to the pre-connection mean. Subgroup analyses reveal that the net effect was driven largely by middle- and top-tier institutions. Finally, I show that NSFNET connection led to a decline in interdisciplinary citations and an increase in within-field citations.
Predicting the value of Chinese patents using patent characteristics: evidence based on a Chinese patent auction
Authors: Yin Zhifeng , Sun Zhen
Published: June 2023

This study revisits the question of predicting patent value with observed patent statistics, exploiting a rare public auction of patents in China in which the starting prices are used as approximates of patent private value. Family size and the number of assignees come out as the most consistent indicators, while notably, forward citations turn out to be not important. This discrepancy with past studies is investigated. We propose some of the institutional features in the Chinese patent system could lead to the forward citations not as informative as their counterpart in other jurisdictions. The findings bear important implications as Chinese patent data are increasingly being used in innovation studies.
Talk or Text? The Role of Communication Modalities in the Adoption of a Non-directive, Goal-Attainment Coaching Chatbot
Authors: Terblanche N H D , Wallis G P , Kidd M
Published: June 2023

Despite the proliferation of chatbots (conversational agents) in increasingly varied contexts, user satisfaction with chatbot interactions remains a challenge. We do not yet fully understand chatbot usability and adoption factors or how to customize chatbots based on users' personality traits. One important and under researched aspect of chatbot design is users' perceptions of different communication modalities such as voice and text. In this between-group study (n = 393 participants), we asked participants to rate an equivalent text-based (n = 189) and voice-based (n = 204) non-directive, goal-attainment coaching chatbot in terms of usability, performance expectancy and risk perception. We also considered participants' personality in terms of extraversion. For usability across all participants, there was no difference between the chatbots for all participants; however, a higher rating of the voicebot was observed in the group classified as introverts and no difference was found for participants classified as extroverts. For performance expectancy all participants, extroverts and introverts rated the textbot higher. Risk ratings showed no difference between bots for all participants, extroverts and introverts. The results suggest that the voicebot was considered slightly easier to use for some participants while the textbot was considered to perform better by all participants. Creators of chatbots should consider using voice as a modality to attract users and text as a mode to accomplish complex tasks. Extraversion did not play a significant part in chatbot communication modality choice. These results may assist in designing context and audience-specific chatbots for increased efficacy and user satisfaction.
In vivo emergence of a still uncommon resistance to fidaxomicin in the urgent antimicrobial resistance threat Clostridioides difficile
Authors: Marchandin Hélène , Anjou Cyril , Poulen Gaëtan , Freeman Jane , Wilcox Mark , Jean-Pierre Hélène , Barbut Frédéric
Published: June 2023

Background

Fidaxomicin is a first-line treatment for Clostridioides difficile infections (CDIs). Fidaxomicin resistance has rarely been reported in this urgent antimicrobial resistance threat as defined by the CDC.

Objectives

To report a case of fidaxomicin-resistant C. difficile isolation in a patient treated by fidaxomicin, characterize the genetic determinant for resistance and the consequences on pathophysiological traits, and review the literature.

Patient and methods

A 38-year-old male patient with several risk factors for CDI experienced three episodes of hospital-acquired CDI and received fidaxomicin for the first episode. The successive isolates were subjected to phenotypic characterization (antimicrobial susceptibility, growth, sporulation ability and toxin production) and WGS analysis to evaluate clonality and modifications associated with resistance.

Results

Resistance to fidaxomicin arose in isolates from the recurrences of CDI (MIC: 16 mg/L). WGS analysis showed a close genetic link between strains suggestive of relapses in this patient. A T3428G mutation in the rpoB gene might be associated with fidaxomicin resistance. The resistance was associated with defects in growth, sporulation and production of toxins. A review of the literature found only three previous fidaxomicin-resistant C. difficile clinical strains.

Conclusions

Although rarely reported, resistance to fidaxomicin may quickly emerge in vivo after a single course of treatment. This observation supports the need for prospective surveillance of the susceptibility of C. difficile to treatment antibiotics. However, the clinical relevance of fidaxomicin resistance still needs to be elucidated, particularly due to its apparent rareness and associated fitness cost.
Vancomycin population pharmacokinetics analysis in Chinese paediatric patients with varying degrees of renal function and ages: development of new practical dosing recommendations
Authors: Chen Jihui , Huang Xiaohui , Yu Liting , Li Jiru , Yang Rui , Li Lixia , Zhou Jia , Yao Huijuan , Bu Shuhong
Published: June 2023

Objectives

To describe the pharmacokinetics of vancomycin in a large Chinese paediatric cohort with varying degrees of renal function and ages and to develop practical dosing guidelines.

Patients and methods

We conducted a retrospective population pharmacokinetic study using data from paediatric patients who received vancomycin between June 2013 and June 2022. A non-linear mixed-effect modelling approach with a one-compartment model structure was applied. Monte Carlo simulations were used to stimulate an optimal dosage regimen to achieve the target of AUC24/MIC between 400 and 650.

Results

We analysed a total of 673 paediatric patients and 1547 vancomycin serum concentrations. Covariate analysis revealed that physiological maturation, renal function, albumin and cardiothoracic surgery (CTS) significantly affected vancomycin pharmacokinetics. The typical clearance and volume of distribution, standardized to 70 kg, were 7.75 L/h (2.3% relative standard error, RSE) and 36.2 L (1.7% RSE), respectively. Based on the model, we proposed an optimal dosing regimen that considers the patient’s age and estimate glomerular filtration rate (eGFR) to achieve a target AUC24/MIC for CTS and non-CTS patients. We also found that a loading dose of 20 mg/kg can help patients with an eGFR of <60 mL/min/1.73 m2 achieve the target AUC on the first day of treatment.

Conclusions

We established vancomycin pharmacokinetic parameters in Chinese paediatric patients and proposed a dosing guideline integrating eGFR, age and CTS status, potentially improving clinical outcomes and reducing nephrotoxicity risk.
Low-diversity microbiota and an increased metabolism of arginine and aromatic amino acids: a hallmark of hepatic encephalopathy in western Mexican patients with alcohol-associated cirrhosis
Authors: Baltazar-Díaz Tonatiuh Abimael , Riggen-Bueno Verónica , Cortina-Romero Donovan Brandon , del Toro-Arreola Susana , Haramati Jesse , Bastidas-Ramírez Blanca Estela , Bueno-Topete Miriam Ruth
Published: June 2023

Aims

To evaluate the composition and functions of the gut microbiota in patients with decompensated alcohol-associated cirrhosis, with and without hepatic encephalopathy (HE).

Methods and results

Faecal samples from 31 inpatients (20 with HE, 11 without HE), and from 18 age-balanced healthy controls (HC), were included. Microbial composition was determined by 16S rRNA amplicon sequencing and analysed using QIIME2. Metabolic pathways were inferred by PICRUSt2, and short-chain fatty acids (SCFAs) quantification was performed by gas chromatography. The gut microbiota of patients with HE was characterized by a diminished α-diversity, compared to no-HE (P < 0.01) and HC (P < 0.001) groups; β-diversity also differed between HE vs no-HE patients (P < 0.05), and between HE vs HC (P < 0.001). In patients with HE, Escherichia/Shigella, Burkholderiales and Lactobacillales taxa predominated. In contrast, patients without HE were characterized by Veillonella and Bacteroides. Reduced levels of faecal SCFAs in both groups correlated with a depletion of beneficial taxa, such as Ruminococcus or Faecalibacterium. PICRUSt2 analysis showed both an enhanced catabolism of arginine through ammonia-producing pathways and chorismate biosynthesis in HE patients, a key precursor of aromatic amino acids.

Conclusions

The gut microbiota of HE patients exhibits a proinflammatory dysbiotic profile, plus metabolic pathways that produce potentially neurotoxic byproducts.
Streptococcus agalactiae virulence factors isolated from bovine mastitis and antibiotic treatment response
Authors: Torres Giovanny , Macias Diana , Reyes-Vélez Julián , Rios-Agudelo Paola , Caraballo-Guzmán Arley
Published: June 2023

Aims

This study aims to characterize the virulence factors of Streptococcus agalactiae strains isolated from bovine mastitis and their potential association with the antibiotic treatment response.

Methods and results

Four different profiles were identified among the 181 S. agalactiae strains using polymerase chain reaction, of which hyl B and cylE were found in 100% of the isolated strains, followed by cfb (99.5%), scpB (40.3%), and lmb (15.5%). The cell invasion assay showed that lmb-positive strains exhibited higher invasion ability than lmb-negative. There was a significant association (P = 0.018) between lmb gene and cows that required more than one treatment cycle.

Conclusions

These results showed that intramammary infections caused by lmb-carrier S. agalactiae strains did not adequately respond to the antibiotics administered, likely because of the presence of this virulence factor, which potentially favours the cell invasion capacity of these strains.
Visualization of health information within immersive virtual reality environments
Authors: Ferguson Allyson , Goldsmith Denise M , Flatley Brennan Patricia
Published: June 2023

The Advanced Visualization Branch of the National Institute of Nursing Research uses computer technologies to study information visualization in support of self-care management. Advanced technologies, such as immersive virtual reality (IVR), afford researchers the opportunity to study health information visualization where user-initiated information search in visually dense settings precedes acquisition, interpretation, and use. While IVR has broad applicability in healthcare, we chose to target lay people managing chronic disease because of the growing unmet need to translate clinical recommendations into everyday behaviors. To explore how lay people seek, acquire, and interpret health information in everyday settings, we developed an IVR grocery store. In this environment, a person can locate food products, read and compare nutrition labels, and use information to make food selections. The goal of this perspective is to introduce the opportunities afforded by IVR to both present and study health information visualization and to highlight critical design considerations.
How to Choose the Right AFM Probe for Your Experiment
Authors: Ted Limpoco F , Beck David E
Published: June 2023

Atomic force microscopes (AFMs) have emerged as the principal enabling tool for nanotechnology research. They are used ubiquitously in a wide range of fields: from 2D materials, semiconductors, ferroelectrics, and batteries to biomolecules, polymers, and cell biology. As the name implies, AFMs are microscopes. However, rather than using focused light or electrons to magnify sample features, AFMs scan a mechanical probe with a very sharp tip over the surface to create a high-resolution 3D topographical image. Further, by modifying the probe composition or structure, other material properties (electrical, mechanical, magnetic, etc.) can be simultaneously measured and mapped onto the topographic image for precise structure/property correlation. Clearly, the probe is key to unlocking the power of the AFM, thus, choosing the right probe is critical. In this article, we will provide novice and experienced users with basic information and guidelines to simplify the AFM probe selection process.
Endothermic self-interacting dark matter in Milky Way-like dark matter haloes
Authors: O’Neil Stephanie , Vogelsberger Mark , Heeba Saniya , Schutz Katelin , Rose Jonah C , Torrey Paul , Borrow Josh , Low Ryan , Adhikari Rakshak , Medvedev Mikhail V , Slatyer Tracy R , Zavala Jesús
Published: June 2023

Self-interacting dark matter (SIDM) offers the potential to mitigate some of the discrepancies between simulated cold dark matter (CDM) and observed galactic properties. We introduce a physically motivated SIDM model to understand the effects of self interactions on the properties of Milky Way and dwarf galaxy sized haloes. This model consists of dark matter with a nearly degenerate excited state, which allows for both elastic and inelastic scattering. In particular, the model includes a significant probability for particles to up-scatter from the ground state to the excited state. We simulate a suite of zoom-in Milky Way-sized N-body haloes with six models with different scattering cross sections to study the effects of up-scattering in SIDM models. We find that the up-scattering reaction greatly increases the central densities of the main halo through the loss of kinetic energy. However, the physical model still results in significant coring due to the presence of elastic scattering and down-scattering. These effects are not as apparent in the subhalo population compared to the main halo, but the number of subhaloes is reduced compared to CDM.
A theory of mass transfer in binary stars
Authors: Cehula Jakub , Pejcha Ondřej
Published: June 2023

Calculation of the mass transfer (MT) rate $\dot{M}_\text{d}$ of a Roche lobe overflowing star is a fundamental task in binary star evolution theory. Most of the existing MT prescriptions are based on a common set of assumptions that combine optically thick and optically thin regimes with different flow geometries. In this work, we develop a new model of MT based on the assumption that the Roche potential sets up a nozzle converging on the inner Lagrangian point and that the gas flows mostly along the axis connecting both stars. We derive a set of 1D hydrodynamic equations governing the gas flow with $\dot{M}_\text{d}$ determined as the eigenvalue of the system. The inner boundary condition directly relates our model to the structure of the donor obtained from 1D stellar evolution codes. We obtain an algebraic solution for the polytropic equation-of-state (EOS). This gives $\dot{M}_\text{d}$ within a factor of 0.9 to 1.0 of existing optically thick prescriptions and reduces to the existing optically thin prescription for isothermal gas. For a realistic EOS, we find that $\dot{M}_\text{d}$ differs by up to a factor of 4 from existing models. We illustrate the effects of our new MT model on a $30\, M_\odot$ low-metallicity star undergoing intensive thermal time-scale MT and find that it is more likely to become unstable to L2 overflow and common-envelope evolution than expected according to MT prescriptions. Our model provides a framework to include additional physics such as radiation or magnetic fields.
Connecting the early afterglow to the prompt GRB and the central engine in the striped jet model
Authors: Damoulakis Michail , Duran Rodolfo Barniol , Giannios Dimitrios
Published: June 2023

Despite a generally accepted framework for describing the gamma-ray burst (GRB) afterglows, the nature of the compact object at the central engine and the mechanism behind the prompt emission remain debated. The striped jet model is a promising venue to connect the various GRB stages since it gives a robust prediction for the relation of jet bulk acceleration, magnetization, and dissipation profile as a function of distance. Here, we use the constraints of the magnetization and bulk Lorentz of the jet flow at the large scales, where the jet starts interacting with the ambient gas in a large sample of bursts to (i) test the striped jet model for the GRB flow and (ii) study its predictions for the prompt emission and the constraints on the nature of the central engine. We find that the peak of the photospheric component of the emission predicted by the model is in agreement with the observed prompt emission spectra in the majority of the bursts in our sample, with a radiative efficiency of about 10 per cent. Furthermore, we adopt two different approaches to correlate the peak energies of the bursts with the type of central engine to find that more bursts are compatible with a neutron star central engine compared to a black hole one. Lastly, we conclude that the model favours broader distribution of stripe length-scales which results in a more gradual dissipation profile in comparison to the case, where the jet stripes are characterized by a single length-scale.
Effective cosmic density field reconstruction with convolutional neural network
Authors: Chen Xinyi , Zhu Fangzhou , Gaines Sasha , Padmanabhan Nikhil
Published: June 2023

We present a cosmic density field reconstruction method that augments the traditional reconstruction algorithms with a convolutional neural network (CNN). Following previous work, the key component of our method is to use the reconstructed density field as the input to the neural network. We extend this previous work by exploring how the performance of these reconstruction ideas depends on the input reconstruction algorithm, the reconstruction parameters, and the shot noise of the density field, as well as the robustness of the method. We build an eight-layer CNN and train the network with reconstructed density fields computed from the Quijote suite of simulations. The reconstructed density fields are generated by both the standard algorithm and a new iterative algorithm. In real space at z = 0, we find that the reconstructed field is 90 per cent correlated with the true initial density out to $k\sim 0.5 \, \mathrm{ h}\, \rm {Mpc}^{-1}$, a significant improvement over $k\sim 0.2 \, \mathrm{ h}\, \rm {Mpc}^{-1}$ achieved by the input reconstruction algorithms. We find similar improvements in redshift space, including an improved removal of redshift space distortions at small scales. We also find that the method is robust across changes in cosmology. Additionally, the CNN removes much of the variance from the choice of different reconstruction algorithms and reconstruction parameters. However, the effectiveness decreases with increasing shot noise, suggesting that such an approach is best suited to high density samples. This work highlights the additional information in the density field beyond linear scales as well as the power of complementing traditional analysis approaches with machine learning techniques.
Common envelope jets supernova with thermonuclear outburst progenitor for the enigmatic supernova remnant W49B
Authors: Grichener Aldana , Soker Noam
Published: June 2023

We suggest a common envelope jets supernova (CEJSN) origin to the supernova remnant (SNR) W49B where jets launched by a neutron star (NS) that collapsed to a black hole (BH) together with a thermonuclear outburst of the disrupted red super giant’s (RGS’s) core powered and shaped the ejecta. The jets account for the highly non-spherical morphology of W49B and the thermonuclear outburst to its high iron abundance. CEJSNe are violent events powered by jets that a NS or a BH launch as they orbit inside a red supergiant star and accrete mass from its envelope and then from its core. We classify the CEJSN process to either a case where the NS/BH enters the core to form a common envelope evolution (CEE) inside the core or to a case where the NS/BH tidally disrupts the core. In the later case, the core material forms an accretion disc around the NS that might experience a thermonuclear outburst, leading to an energetic event powered by both jets and thermonuclear burning. We term this scenario thermonuclear CEJSN. We find that the maximum core mass that leads to this scenario with a NS is 2 M⊙ ≲ Mcore ≲ 3.5 M⊙. We estimate the event rates of CEJSN that go through tidal disruption of the core by a NS to be 5 per 1000 core collapse supernovae.
Initial sizes of star clusters: implications for cluster dissolution during galaxy evolution
Authors: Reina-Campos Marta , Sills Alison , Bichon Godefroy
Published: June 2023

Massive star clusters are often used as tracers of galaxy formation and assembly. In order to do so, we must understand their properties at formation, and how those properties change with time, galactic environment, and galaxy assembly history. The two most important intrinsic properties that govern star cluster evolution are mass and radius. In this paper, we investigate 10 theoretically and observationally motivated initial size–mass relations for star clusters, and evolve populations of clusters through galaxy formation models. We compare our results to each other and to observations of cluster populations in M83, M31, and the Milky Way. We find that none of our size–mass relations agree with the observations after 6–10 Gyr of evolution. We can successfully reproduce the cluster mass functions with models that have a small range of initial radii, and which do not allow cluster radii to change with time. However, these models do not agree with our understanding of cluster evolution, which does involve radius evolution, and do not match the observed distributions of radii. We note that there is a region of parameter space where clusters are optimally protected from both tidal shocks and evaporation due to two-body relaxation. Clusters that are allowed to evolve into this parameter space will likely survive. An improved understanding of both mass and radius evolution of star clusters in realistic, time-varying galactic potentials is necessary to appropriately make the connection between present-day cluster properties and their use as tracers of galaxy formation and assembly.
Analysis of accretion disc structure and stability using open code for vertical structure
Authors: Tavleev A S , Lipunova G V , Malanchev K L
Published: June 2023

Radial structure of accretion discs around compact objects is often described using analytic approximations which are derived from averaging or integrating vertical structure equations. For non-solar chemical composition, partial ionization, or for supermassive black holes, this approach is not accurate. Additionally, radial extension of ‘analytically-described’ disc zones is not evident in many cases. We calculate vertical structure of accretion discs around compact objects, with and without external irradiation, with radiative and convective energy transport taken into account. For this, we introduce a new open Python code, allowing different equations of state and opacity laws, including tabular values. As a result, radial structure and stability ‘S-curves’ are calculated for specific disc parameters and chemical composition. In particular, based on more accurate power-law approximations for opacity in the disc, we supply new analytic formulas for the farthest regions of the hot disc around stellar-mass object. On calculating vertical structure of a self-irradiated disc, we calculate a self-consistent value of the irradiation parameter Cirr for stationary α-disc. We find that, for a fixed shape of the X-ray spectrum, Cirr depends weakly on the accretion rate but changes with radius, and the dependence is driven by the conditions in the photosphere and disc opening angle. The hot zone extent depends on the ratio between irradiating and intrinsic flux: corresponding relation for $T_{\rm irr,\, crit}$ is obtained.
Keck spectroscopy of NGC 1052-DF9: stellar populations in the context of the NGC 1052 group
Authors: Gannon Jonah S , Buzzo Maria Luisa , Ferré-Mateu Anna , Forbes Duncan A , Brodie Jean P , Romanowsky Aaron J
Published: June 2023

In this study, we use Keck/Keck Cosmic Web Imager spectroscopy to measure the age, metallicity, and recessional velocity of NGC 1052-DF9 (DF9), a dwarf galaxy in the NGC 1052 group. We compare these properties to those of two other galaxies in the group, NGC 1052-DF2 and NGC 1052-DF4, which have low dark matter content. The three galaxies are proposed constituents of a trail of galaxies recently hypothesized to have formed as part of a ‘bullet dwarf’ collision. We show that the ages and total metallicities of the three galaxies are within uncertainties of one another which may be expected if they share a related formation pathway. However, the recessional velocity we recover for DF9 (1680 ± 10 km s−1) is higher than predicted for a linearly projected interpretation of the ‘bullet dwarf’ trail. DF9 is then either not part of the trail or the correlation of galaxy velocities along the trail is not linear in 2D projection due to their 3D geometry. After examining other proposed formation pathways for the galaxies, none provide a wholly satisfactory explanation for all of their known properties. We conclude further work is required to understand the formation of this interesting group of galaxies.
Discovery of delta Scuti variables in eclipsing binary systems II. Southern TESS field search
Authors: Kahraman Aliçavuş F , Çoban Ç G , Çelik E , Dogan D S , Ekinci O , Aliçavuş F
Published: June 2023

The presence of pulsating stars in eclipsing binary systems (EBs) makes these objects significant since they allow us to investigate the stellar interior structure and evolution. Different types of pulsating stars could be found in EBs, such as δ Scuti variables. δ Scuti stars in EBs have been known for decades, and the increasing number of such systems is important for understanding pulsational structure. Hence, in this study, research was carried out on the southern TESS field to discover new δ Scuti stars in EBs. We produced an algorithm to search for detached and semidetached EBs considering three steps: the orbital period (Porb)’s harmonics in the Fourier spectrum, skewness of the light curves, and classification of upsilon program. If two of these steps classify a system as an EB, the algorithm also identifies it as an EB. The TESS pixel files of targets were also analysed to see whether the fluxes were contaminated by other systems. No contamination was found. We researched the existence of pulsation through EBs with a visual inspection. To confirm δ Scuti-type oscillations, the binary variation was removed from the light curve, and residuals were analysed. Consequently, we identified 42 δ Scuti candidates in EBs. The Porb, L, and MV of systems were calculated. Their positions on the H–R diagram and the known orbital-pulsation period relationship were analysed. We also examined our targets to see if any of them showed frequency modulation with the orbital period and discovered one candidate of tidally tilted pulsators.
What causes the formation of discs and end of bursty star formation?
Authors: Hopkins Philip F , Gurvich Alexander B , Shen Xuejian , Hafen Zachary , Grudić Michael Y , Kurinchi-Vendhan Shalini , Hayward Christopher C , Jiang Fangzhou , Orr Matthew E , Wetzel Andrew , Kereš Dušan , Stern Jonathan , Faucher-Giguère Claude-André , Bullock James , Wheeler Coral , El-Badry Kareem , Loebman Sarah R , Moreno Jorge , Boylan-Kolchin Michael , Quataert Eliot
Published: June 2023

As they grow, galaxies can transition from irregular/spheroidal with ‘bursty’ star formation histories (SFHs), to discy with smooth SFHs. But even in simulations, the direct physical cause of such transitions remains unclear. We therefore explore this in a large suite of numerical experiments re-running portions of cosmological simulations with widely varied physics, further validated with existing FIRE simulations. We show that gas supply, cooling/thermodynamics, star formation model, Toomre scale, galaxy dynamical times, and feedback properties do not have a direct causal effect on these transitions. Rather, both the formation of discs and cessation of bursty star formation are driven by the gravitational potential, but in different ways. Disc formation is promoted when the mass profile becomes sufficiently centrally concentrated in shape (relative to circularization radii): we show that this provides a well-defined dynamical centre, ceases to support the global ‘breathing modes’ that can persist indefinitely in less-concentrated profiles and efficiently destroy discs, promotes orbit mixing to form a coherent angular momentum, and stabilizes the disc. Smooth SF is promoted by the potential or escape velocity Vesc (not circular velocity Vc) becoming sufficiently large at the radii of star formation that cool, mass-loaded (momentum-conserving) outflows are trapped/confined near the galaxy, as opposed to escaping after bursts. We discuss the detailed physics, how these conditions arise in cosmological contexts, their relation to other correlated phenomena (e.g. inner halo virialization, vertical disc ‘settling’), and observations.
The challenges of identifying Population III stars in the early Universe
Authors: Katz Harley , Kimm Taysun , Ellis Richard S , Devriendt Julien , Slyz Adrianne
Published: June 2023

The recent launch of JWST has enabled the exciting prospect of detecting the first generation of metal-free, Population III (Pop. III) stars. Determining characteristics that robustly signify Pop. III stars against other possible contaminants represents a key challenge. To this end, we run high-resolution (sub-pc) cosmological radiation hydrodynamics simulations of the region around a dwarf galaxy at z ≥ 10 to predict the emission line signatures of the Pop. III/Pop. II transition. We show that the absence of metal emission lines is a poor diagnostic of Pop. III stars because metal-enriched galaxies can maintain low [O iii] 5007 Å that may be undetectable due to sensitivity limits. Combining spectral hardness probes (e.g. He ii 1640 Å/H α) with metallicity diagnostics is more likely to probe metal-free stars, although contamination from Wolf−Rayet stars, X-ray binaries, or black holes may be important. The hard emission from Pop. III galaxies fades fast due to the short stellar lifetimes of massive stars, which could further inhibit detection. Pop. III stars may be identifiable after they evolve off the main sequence due to the cooling radiation from nebular gas or a supernova remnant; however, these signatures are also short-lived (i.e. few Myr). Contaminants including flickering black holes might confuse this diagnostic. While JWST will provide a unique opportunity to spectroscopically probe the nature of the earliest galaxies, both the short time-scales associated with pristine systems and ambiguities in interpreting emission lines may hinder progress. Special care will be needed before claiming the discovery of systems with pure Pop. III stars.
Evidence of radius inflation in radiative GCM models of WASP-76b due to the advection of potential temperature
Authors: Sainsbury-Martinez Felix , Tremblin Pascal , Schneider Aaron David , Carone Ludmila , Baraffe Isabelle , Chabrier Gilles , Helling Christiane , Decin Leen , Jørgensen Uffe Gråe
Published: June 2023

Understanding the discrepancy between the radii of observed hot Jupiters and standard ‘radiative-convective’ models remains a hotly debated topic in the exoplanet community. One mechanism which has been proposed to bridge this gap, and which has recently come under scrutiny, is the vertical advection of potential temperature from the irradiated outer atmosphere deep into the interior, heating the deep unirradiated atmosphere, warming the internal adiabat, and resulting in radius inflation. Specifically, a recent study which explored the atmosphere of WASP-76b using a 3D non-grey GCM suggested that their models lacked radius inflation, and hence any vertical enthalpy advection. Here we perform additional analysis of these, and related models, focusing on an explicit analysis of vertical enthalpy transport and the resulting heating of the deep atmosphere compared with 1D models. Our results indicate that, after any evolution linked with initialization, all the WASP-76b models considered here exhibit significant vertical enthalpy transport, heating the deep atmosphere significantly when compared with standard 1D models. Furthermore, comparison of a long time-scale (and hence near steady-state) model with a Jupiter-like internal-structure model suggests not only strong radius-inflation, but also that the model radius, 1.98 RJ, may be comparable with observations (1.83 ± 0.06 RJ). We thus conclude that the vertical advection of potential temperature alone is enough to explain the radius inflation of WASP-76b, and potentially other irradiated gas giants, albeit with the proviso that the exact strength of the vertical advection remains sensitive to model parameters, such as the inclusion of deep atmospheric drag.
Possible contribution of X-ray binary jets to the Galactic cosmic ray and neutrino flux
Authors: Kantzas D , Markoff S , Cooper A J , Gaggero D , Petropoulou M , De La Torre Luque P
Published: June 2023

For over a century, the identification of high-energy cosmic ray (CR) sources remains an open question. For Galactic CRs with energy up to 1015 eV, supernova remnants (SNRs) have traditionally been thought the main candidate source. However, recent TeV γ-ray observations have questioned the SNR paradigm. Propagating CRs are deflected by the Galactic magnetic field, hence, γ-rays and neutrinos produced via inelastic hadronic interactions are the only means for unveiling the CR sources. In this work, we study the γ-ray and neutrino emission produced by CRs accelerated inside Galactic jets of stellar-mass black holes in X-ray binaries (BHXBs). We calculate the intrinsic neutrino emission of two prototypical BHXBs , Cygnus X–1 and GX 339–4, for which we have high-quality, quasi-simultaneous multiwavelength spectra. Based on these prototypical sources, we discuss the likelihood of the 35 known Galactic BHXBs to be efficient CR accelerators. Moreover, we estimate the potential contribution to the CR spectrum of a viable population of BHXBs that reside in the Galactic plane. When these BHXBs go into outburst, they may accelerate particles up to hundreds of TeV that contribute to the diffuse γ-ray and neutrino spectra while propagating in the Galactic medium. Using HERMES, an open-source code that calculates the hadronic processes along the line of sight, we discuss the contribution of BHXBs to the diffuse γ-ray and neutrino fluxes, and compare these to their intrinsic γ-ray and neutrino emissions. Finally, we discuss the contribution of BHXBs to the observed spectrum of Galactic CRs.
Atmospheres as windows into sub-Neptune interiors: coupled chemistry and structure of hydrogen–silane–water envelopes
Authors: Misener William , Schlichting Hilke E , Young Edward D
Published: June 2023

Sub-Neptune exoplanets are commonly hypothesized to consist of a silicate-rich magma ocean topped by a hydrogen-rich atmosphere. Previous work studying the outgassing of silicate material has demonstrated that such atmosphere–interior interactions can affect the atmosphere’s overall structure and extent. However, these models only considered SiO in an atmosphere of hydrogen gas, without considering chemical reactions between them. Here, we couple calculations of the chemical equilibrium between H, Si, and O species with an atmospheric structure model. We find that substantial amounts of silane, SiH4, and water, H2O, are produced by the interaction between the silicate-rich interior and hydrogen-rich atmosphere. These species extend high into the atmosphere, though their abundance is greatest at the hottest, deepest regions. For example, for a 4 M⊕ planet with an equilibrium temperature of 1000 K, a base temperature of 5000 K, and a 0.1 M⊕ hydrogen envelope, silicon species and water can comprise 30 per cent of the atmosphere by number at the bottom of the atmosphere. Due to this abundance enhancement, we find that convection is inhibited at temperatures ≳2500 K. This temperature is lower, implying that the resultant non-convective region is thicker, than was found in previous models that did not account for atmospheric chemistry. Our findings show that significant endogenous water is produced by magma–hydrogen interactions alone, without the need to accrete ice-rich material. We discuss the observability of the signatures of atmosphere–interior interaction and directions for future work, including condensate lofting and more complex chemical networks.
A unified exploration of the chronology of the Galaxy
Authors: Stokholm Amalie , Aguirre Børsen-Koch Víctor , Stello Dennis , Hon Marc , Reyes Claudia
Published: June 2023

The Milky Way has distinct structural stellar components linked to its formation and subsequent evolution, but disentangling them is non-trivial. With the recent availability of high-quality data for a large numbers of stars in the Milky Way, it is a natural next step for research in the evolution of the Galaxy to perform automated explorations with unsupervised methods of the structures hidden in the combination of large-scale spectroscopic, astrometric, and asteroseismic data sets. We determine precise stellar properties for 21 076 red giants, mainly spanning 2–15 kpc in Galactocentric radii, making it the largest sample of red giants with measured asteroseismic ages available to date. We explore the nature of different stellar structures in the Galactic disc by using Gaussian mixture models as an unsupervised clustering method to find substructure in the combined chemical, kinematic, and age subspace. The best-fitting mixture model yields four distinct physical Galactic components in the stellar disc: the thin disc, the kinematically heated thin disc, the thick disc, and the stellar halo. We find hints of an age asymmetry between the Northern and Southern hemisphere, and we measure the vertical and radial age gradient of the Galactic disc using the asteroseismic ages extended to further distances than previous studies.