bluuebunny/crossref_metadata_2025 huggingface dataset:
Disruption of layer-specific visual processing in a model of focal neocortical epilepsy
Authors: Panarese Alessandro , Vissani Matteo , Meneghetti Nicolò , Vannini Eleonora , Cracchiolo Marina , Micera Silvestro , Caleo Matteo , Mazzoni Alberto , Restani Laura
Published: September 2022

The epileptic brain is the result of a sequence of events transforming normal neuronal populations into hyperexcitable networks supporting recurrent seizure generation. These modifications are known to induce fundamental alterations of circuit function and, ultimately, of behavior. However, how hyperexcitability affects information processing in cortical sensory circuits is not yet fully understood. Here, we investigated interlaminar alterations in sensory processing of the visual cortex in a mouse model of focal epilepsy. We found three main circuit dynamics alterations in epileptic mice: (i) a spreading of visual contrast-driven gamma modulation across layers, (ii) an increase in firing rate that is layer-unspecific for excitatory units and localized in infragranular layers for inhibitory neurons, and (iii) a strong and contrast-dependent locking of firing units to network activity. Altogether, our data show that epileptic circuits display a functional disruption of layer-specific organization of visual sensory processing, which could account for visual dysfunction observed in epileptic subjects. Understanding these mechanisms paves the way to circuital therapeutic interventions for epilepsy.
The Epidemiology of Sapovirus in the Etiology, Risk Factors, and Interactions of Enteric Infection and Malnutrition and the Consequences for Child Health and Development Study: Evidence of Protection Following Natural Infection
Authors: Rouhani Saba , Peñataro Yori Pablo , Paredes Olortegui Maribel , Lima Aldo A , Ahmed Tahmeed , Mduma Estomih R , George Ajila , Samie Amidou , Svensen Erling , Lima Ila , Mondal Dinesh , Mason Carl J , Kalam Adil , Guerrant Richard L , Lang Dennis , Zaidi Anita , Kang Gagandeep , Houpt Eric , Kosek Margaret N
Published: September 2022

Background

Sapovirus is one of the principal agents of acute viral enteritis in children. Because it has not been routinely included in diagnostic evaluations, the epidemiology and natural history remain poorly described.

Methods

A birth cohort of 1715 children from 8 countries contributed surveillance samples (n = 35 620) and diarrheal specimens (n = 6868) from 0 to 24 months of age. Sapovirus was detected by quantitative polymerase chain reaction concurrently to other enteropathogens using multiarray cards. Logistic regression was used to identify risk factors, and longitudinal models were employed to estimate incidence rates and evaluate evidence of protective immunity.

Results

Sapovirus was detected in 24.7% (n = 1665) of diarrheal stools and 12.8% (n = 4429) of monthly surveillance samples. More than 90% of children were infected and 60% experienced sapovirus diarrhea in the first 2 years of life. Breastfeeding and higher socioeconomic status were associated with reduced incidence of infection and illness. Specimens with sapovirus detected had an increased odds of coinfection with rotavirus (odds ratio [OR], 1.6 [95% confidence interval {CI}, 1.3–2.0]), astrovirus (OR, 1.5 [95% CI, 1.3–1.7]), adenovirus (OR, 1.3 [95% CI, 1.1–1.5]), and Shigella (OR, 1.4 [95% CI, 1.3–1.6]). Prior infection with sapovirus conferred a risk reduction of 22% for subsequent infection (hazard ratio [HR], 0.78 [95% CI, .74–.85]) and 24% for subsequent diarrhea (95% CI, 11.0%–35.0%; HR, 0.76).

Conclusions

Sapovirus is a common cause of early childhood diarrhea. Further research on coinfections is warranted. Evidence of acquired immunity was observed even in the absence of genotype-specific analysis for this pathogen of known genetic diversity.
Optimal Timing of Antiretroviral Therapy Initiation in Children and Adolescents With Human Immunodeficiency Virus-Associated Pulmonary Tuberculosis
Authors: Kay Alexander , Mendez-Reyes Jose , Devezin Tara , Bakaya Meenakshi , Steffy Teresa , Dlamini Sandile , Msekandiana Amos , Ness Tara , Bacha Jason , Amuge Pauline , Matshaba Mogomotsi , Chodota Moses , Nyasulu Phoebe , Thahane Lineo , Mwita Lumumbwa , Kekitiinwa Adeodata , DiNardo Andrew , Lukhele Bhekumusa , Kirchner H Lester , Mandalakas Anna
Published: September 2022

Background

There is insufficient evidence in children and adolescents with human immunodeficiency virus (CAHIV) to guide the timing of antiretroviral treatment (ART) initiation after starting treatment for pulmonary tuberculosis (pTB). To address this knowledge gap, we evaluated the risk of mortality associated with timing of ART initiation in ART-naive CAHIV treated for pTB.

Methods

Data were extracted from electronic medical records of ART-naive patients, aged 0–19 years, who were treated for HIV-associated pTB at Baylor Centers of Excellence in Botswana, Eswatini, Malawi, Lesotho, Tanzania, or Uganda between 2013 and 2020. Data were analyzed against a primary outcome of all-cause mortality with unadjusted Kaplan-Meier curves and Cox proportional hazard models.

Results

The study population included 774 CAHIV with variable intervals to ART initiation after starting TB treatment: <2 weeks (n = 266), 2 weeks to 2 months (n = 398), >2 months (n = 66), and no ART initiated (n = 44). Adjusted Cox proportional hazards models demonstrated increased mortality 1 year from TB treatment initiation in children never starting ART (adjusted HR [aHR]: 2.67; 95% CI: 1.03, 6.94) versus children initiating ART between 2 weeks and 2 months from TB treatment initiation. Mortality risk did not differ for the <2-weeks group (aHR: 1.02; 95% CI: .55, 1.89) versus the group initiating ART between 2 weeks and 2 months.

Conclusions

This retrospective study demonstrated no increase in mortality among CAHIV initiating ART <2 weeks from TB treatment initiation. Given the broad health benefits of ART, this evidence supports the recent WHO recommendation for CAHIV to initiate ART within 2 weeks of initiating TB treatment.
Practical Implementation of Encoding Range Top-2 Queries
Authors: Park Wooyoung , Jo Seungbum , Rao Satti Srinivasa
Published: September 2022

We design a practical variant of an encoding for range Top-2 query (RT2Q) and evaluate its performance. Given an array $A[1,n]$ of $n$ elements from a total order, the range Top-2 encoding problem is to construct a data structure that answers ${\textsf{RT2Q}}{}$, which returns the positions of the first and second largest elements within a given range of $A$, without accessing the array $A$ at query time. We design the following two implementations: (i) an implementation based on an alternative representation of Davoodi et al.’s [Phil. Trans. Royal Soc. A, 2016] data structure, which supports queries efficiently. Experimental results show that our implementation is efficient in practice and gives improved time-space trade-offs compared with the indexing data structures (which keep the original array $A$ as part of the data structure) for range maximum queries. (ii) Another implementation based on Jo et al.’s ${\textsf{RT2Q}}{}$ encoding on $2 \times n$ array [CPM, 2016], which can be constructed in $O(n)$ time. We compare our encoding with Gawrychowski and Nicholson’s optimal encoding [ICALP, 2015] and show that in most cases, our encoding shows faster construction time while using a competitive space in practice.
Shifting of Cognitive Assessments Between Face-to-Face and Telephone Administration: Measurement Considerations
Authors: Smith Jason R , Gibbons Laura E , Crane Paul K , Mungas Dan M , Glymour M Maria , Manly Jennifer J , Zahodne Laura B , Rose Mayeda Elizabeth , Jones Richard N , Gross Alden L
Published: September 2022

Objectives

Telephone-administered cognitive assessments are a cost-effective and sometimes necessary alternative to face-to-face assessments. There is limited information in large studies concerning mode effects, or differences in cognition attributable to the assessment method, as a potential measurement threat. We evaluated mode effects on cognitive scores using a population-based sample of community-living older adults.

Methods

We used data from participants aged 65–79 in the 2014 Health and Retirement Study for whom the interview mode was randomized (n = 6,825). We assessed mode differences in test means, whether mode modifies associations of cognition with criterion variables, and formal measurement invariance testing.

Results

Relative to face-to-face assessment, telephone assessment was associated with higher scores for memory and calculation (0.06 to 0.013 standard deviations [SD]) and lower scores for nonmemory items (−0.09 to −0.01 SD). Cognition was significantly differentially related to instrumental activities of daily living difficulty depending on assessment mode. Measurement invariance testing identified evidence of mode differences in certain tests as a function of mode: adjusting for underlying cognition, the largest mode differences in memory and attention: immediate noun recall, delayed word recall, and serial-7s scores were higher given telephone administration.

Discussion

Differences by mode of administration are apparent in cognitive measurement in older adults, albeit to a small degree in our study, and most pronounced for tests of memory and attention. The importance of accounting for mode differences ultimately depends on one’s research question and study sample: not all associations may be affected by mode differences, and such modification may only be apparent among those with lower cognitive functioning.
Spectral element method for 3-D controlled-source electromagnetic forward modelling using unstructured hexahedral meshes
Authors: Weiss M , Kalscheuer T , Ren Z
Published: September 2022

For forward modelling of realistic 3-D land-based controlled-source electromagnetic (EM) problems, we develop a parallel spectral element approach, blending the flexibility and versatility of the finite element method in using unstructured grids with the accuracy of the spectral method. Complex-shaped structures and topography are accommodated by using unstructured hexahedral meshes, in which the elements can have curved edges and non-planar faces. Our code is the first spectral element algorithm in EM geophysics that uses the total field formulation (here that of the electric field). Combining unstructured grids and a total field formulation provides advantages in dealing with topography, in particular, when the transmitter is located on rough surface topography. As a further improvement over existing spectral element methods, our approach does not only allow for arbitrary distributions of conductivity, but also of magnetic permeability and dielectric permittivity. The total electric field on the elements is expanded in terms of high-order Lagrangian interpolants, and element-wise integration in the weak form of the boundary value problem is accomplished by Gauss–Legendre–Lobatto quadrature. The resulting complex-valued linear system of equations is solved using the direct solver MUMPS, and, subsequently, the magnetic field is computed at the points of interest by Faraday’s law. Five numerical examples comprehensively study the benefits of this algorithm. Comparisons to semi-analytical and finite element results confirm accurate representation of the EM responses and indicate low dependency on mesh discretization for the spectral element method. A convergence study illuminates the relation between high order polynomial approximation and mesh size and their effects on accuracy and computational cost revealing that high-order approximation yields accurate modelling results for very coarse meshes but is accompanied by high computational cost. The presented numerical experiments give evidence that 2nd and 3rd degree polynomials in combination with moderately discretized meshes provide better trade-offs in terms of computational resources and accuracy than lowest and higher order spectral element methods. To our knowledge, our final example that includes pronounced surface topography and two geometrically complicated conductive anomalies represents the first successful attempt at using 2nd order hexahedral elements supporting curved edges and non-planar faces in controlled-source EM geophysics.
Pseudostable Hodge Integrals
Authors: Cavalieri Renzo , Gallegos Joel , Ross Dustin , Van Over Brandon , Wise Jonathan
Published: September 2022

This paper initiates a study of Hodge integrals on moduli spaces of pseudostable curves. We prove an explicit comparison formula that allows one to effectively compute any pseudostable Hodge integral in terms of intersection numbers on moduli spaces of stable curves, and we use this comparison to prove that pseudostable Hodge integrals are equal to their stable counterparts when they are linear in lambda classes, but not when they are nonlinear. This suggests that pseudostable Gromov–Witten invariants are equal to usual Gromov–Witten invariants for target curves, but not for higher-dimensional target varieties.
Low Prevalence of Interferon α Autoantibodies in People Experiencing Symptoms of Post–Coronavirus Disease 2019 (COVID-19) Conditions, or Long COVID
Authors: Peluso Michael J , Mitchell Anthea , Wang Chung Yu , Takahashi Saki , Hoh Rebecca , Tai Viva , Durstenfeld Matthew S , Hsue Priscilla Y , Kelly J Daniel , Martin Jeffrey N , Wilson Michael R , Greenhouse Bryan , Deeks Steven G , DeRisi Joseph L , Henrich Timothy J
Published: September 2022

Interferon (IFN)–specific autoantibodies have been implicated in severe coronavirus disease 2019 (COVID-19) and have been proposed as a potential driver of the persistent symptoms characterizing “long COVID,” a type of postacute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We report that only 2 of 215 participants with convalescent SARS-CoV-2 infection tested over 394 time points, including 121 people experiencing long COVID symptoms, had detectable IFN-α2 antibodies. Both had been hospitalized during the acute phase of the infection. These data suggest that persistent anti-IFN antibodies, although a potential driver of severe COVID-19, are unlikely to contribute to long COVID symptoms in the postacute phase of the infection.
Enhancing antimicrobial surveillance in hospitals in England: a RAND-modified Delphi
Authors: Patel Selina , Jhass Arnoupe , Hopkins Susan , Shallcross Laura
Published: September 2022

Background

Optimizing antimicrobial use (AMU) is key to reducing antimicrobial-resistant infections, but current AMU monitoring in hospital provides limited insights for quality improvement.

Objectives

To understand stakeholders’ priorities for developing national AMU surveillance in English hospitals to serve the needs of national policy makers and front-line practitioners.

Methods

Characteristics of existing AMU surveillance systems were identified from a previous systematic review and categorized by the Acceptability, Practicability, Effectiveness, Affordability, Side-effects and Equity (APEASE) criteria. Stakeholders prioritized characteristics using a two-round RAND-modified Delphi (rating round 1, telephone panel discussion, rating round 2). Findings informed the design of a framework used to assess the extent to which existing surveillance approaches meet stakeholders’ needs.

Results

Between 17/09/19 and 01/11/19, 24 stakeholders with national and local roles related to AMU prioritized 23 characteristics of AMU surveillance describing: resource for surveillance, data collection, data availability and pathways to translate information from surveillance into practice. No existing surveillance approaches demonstrated all prioritized characteristics. The most common limitation was failure to facilitate clinician engagement with AMU through delays in data access and/or limited availability of disaggregated metrics of prescribing.

Conclusions

Current surveillance delivers national public health priorities but improving stewardship demands patient-level data linked to clinical outcomes. This study offers a framework to develop current surveillance to meet the needs of local stakeholders in England. Increased investment in data infrastructure and training is essential to make information held within electronic systems available to front-line clinicians to facilitate quality improvement.
Toward informatics-enabled preparedness for natural hazards to minimize health impacts of climate change
Authors: Phuong Jimmy , Riches Naomi O , Calzoni Luca , Datta Gora , Duran Deborah , Lin Asiyah Yu , Singh Ramesh P , Solomonides Anthony E , Whysel Noreen Y , Kavuluru Ramakanth
Published: September 2022

Natural hazards (NHs) associated with climate change have been increasing in frequency and intensity. These acute events impact humans both directly and through their effects on social and environmental determinants of health. Rather than relying on a fully reactive incident response disposition, it is crucial to ramp up preparedness initiatives for worsening case scenarios. In this perspective, we review the landscape of NH effects for human health and explore the potential of health informatics to address associated challenges, specifically from a preparedness angle. We outline important components in a health informatics agenda for hazard preparedness involving hazard-disease associations, social determinants of health, and hazard forecasting models, and call for novel methods to integrate them toward projecting healthcare needs in the wake of a hazard. We describe potential gaps and barriers in implementing these components and propose some high-level ideas to address them.
Ractopamine and age alter oxygen use and nitrogen metabolism in tissues of beef steers
Authors: Eisemann Joan H , Nienaber John A , Huntington Gerald B
Published: September 2022

The objective was to quantify the effects of age and ractopamine (RAC) on whole body oxygen consumption and Leu flux, and oxygen flux and metabolism of nitrogenous compounds by the portal-drained viscera (PDV), liver, and hindquarters (HQ) of steers. Multicatheterized steers were fed a high energy diet every 2 h in 12 equal portions. Five younger steers (body weight, [BW] = 223 ± 10.1 kg) were 6 mo old and five older steers (BW = 464 ± 16.3 kg) were 14 mo old. Treatments were control (Cont) or 80 mg RAC per kg diet in a crossover design. Nitrogen (N) balance was measured on day 9 to 13. Whole body oxygen consumption and net flux were measured on day 11 and day 13, and net flux of N variables, Phe and Leu kinetics were measured on day 13. Whole body oxygen consumption increased (P < 0.05) in response to RAC in older but not younger steers. Retained N was greater (P = 0.009) for younger than older steers and increased (P = 0.010) with RAC in both ages of steers. Nitrogen retained as a percentage of N apparently absorbed increased (P < 0.05) in the older steers but not the younger steers in response to RAC. Oxygen uptake was greater (P < 0.05) in PDV, liver, and total splanchnic tissues in the younger steers and there was no response to RAC. In contrast, oxygen uptake in HQ increased (P < 0.05) with RAC in the older but not the younger steers. Concentration and net PDV release of α-amino N (AAN) were not affected by age or RAC. Uptake of AAN by liver decreased with RAC (P = 0.001). Splanchnic release of AAN was greater in younger steers (P = 0.020) and increased (P = 0.024) in response to RAC. For HQ tissues, uptake (P = 0.005) and extraction (P = 0.005) of AAN were lesser in older than younger steers and both increased (P = 0.001) in response to RAC. Based on Phe kinetics in HQ, RAC increased (P < 0.05) protein synthesis in older steers but not in younger steers. In contrast, protein breakdown decreased (P < 0.05) in response to RAC in younger steers. In response to RAC, protein degradation was less (P < 0.05) in younger than older steers. Based on Leu kinetics, whole body protein synthesis was greater in the younger steers (P = 0.022) but not altered in response to RAC. Ractopamine enhanced lean tissue growth by increasing supply of AAN to peripheral tissues and altering protein metabolism in HQ. These metabolic responses are consistent with established responses to RAC in production situations.
The mechanisms of S-wave attenuation in grainstones
Authors: Li Guangquan , Zhao Hai , Wang Qianhe , Wang Zhenwei , Luo Haitao
Published: September 2022

The dominant mechanism of P-wave attenuation in fluid-saturated rock is well known to be the pore-scale squirt. However, the S-wave does not change the average fluid pressure in a pore and the pore volume stays unchanged. As such, the S-wave has a mechanism of attenuation distinctively different from the P-wave. This paper attempts to resolve the mechanisms of S-wave attenuation in fluid-saturated grainstones. The first mechanism is the viscous boundary layer in a fracture, the second is fluid acceleration plus a real-number permeability and the third mechanism is fluid acceleration plus a complex-number permeability (which arises from the viscous boundary layer). D'Euville limestone and Berea sandstone are used as illustrative examples. Ultrasonic velocity and the quality factor due to pore fluid (Qs) are compared between the three models and measurement. The results indicate that fluid acceleration plus the viscous boundary layer is the mechanism of S-wave attenuation in the water-saturated grainstones. In addition, the third model reveals a novel convex in the curve of Qs in the frequency range of 107–108 Hz.
A reference genome assembly of the declining tricolored blackbird,Agelaius tricolor
Authors: Ballare Kimberly M , Escalona Merly , Barr Kelly , Seligmann William , Sacco Samuel , Sahasrabudhe Ruta Madhusudan , Nguyen Oanh , Wyckoff Christy , Smith Thomas B , Shapiro Beth
Published: September 2022

The tricolored blackbird, Agelaius tricolor, is a gregarious species that forms enormous breeding and foraging colonies in wetland and agricultural habitats, primarily in California, USA. Once extremely abundant, species numbers have declined dramatically in the past century, largely due to losses of breeding and foraging habitats. Tricolored blackbirds are currently listed as Endangered by the IUCN, and Threatened under the California Endangered Species Act. Increased genetic information is needed to detail the evolutionary consequences of a species-wide bottleneck and inform conservation management. Here, we present a contiguous tricolored blackbird reference genome, assembled with PacBio HiFi long reads and Dovetail Omni-C data to generate a scaffold-level assembly containing multiple chromosome-length scaffolds. This genome adds a valuable resource for important evolutionary and conservation research on tricolored blackbirds and related species.
Phytochemistry and biological activity of Lansium domesticum Corr. species: a review
Authors: Mayanti Tri , Sinaga Siska Elisahbet , Supratman Unang
Published: September 2022

Objectives

This study aims to review and describe the ethnobotanical, phytochemical and biological activity of various extracts and compounds isolated from Lansium domesticum Corr. from 1967 to 2022 and to study the opportunities that can be developed in the future in the pharmaceutical and pharmacology fields. The related articles, followed by the classification of L. domesticum Corr. according to ethnobotanical, biological and phytochemical properties, were collected from SciFinder, Google Scholar and PubMed.

Key findings

More than 80 compounds have been isolated and identified from L. domesticum Corr., including terpenoids and their glycosides. Furthermore, the pharmacological activity of the extracts and pure compounds of L. domesticum Corr. tested in vitro and in vivo were mainly confirmed to include antifeedant, antimalarial, antimicrobial, antibacterial, and radical scavenging activity, antimutagenic, and anticancer.

In conclusion, based on this review, all data on the phytochemical and biological activity of L. domesticum Corr. can be used to support scientists in further research aim to determine the reaction mechanism of the extracts or compounds and need to be further validated using in vivo models together with toxicological analysis to establish their maximum tolerated dose.
The double round-robin population unravels the genetic architecture of grain size in barley
Authors: Shrestha Asis , Cosenza Francesco , van Inghelandt Delphine , Wu Po-Ya , Li Jinquan , Casale Federico A , Weisweiler Marius , Stich Benjamin
Published: September 2022

Grain number, size and weight primarily determine the yield of barley. Although the genes regulating grain number are well studied in barley, the genetic loci and the causal gene for sink capacity are poorly understood. Therefore, the primary objective of our work was to dissect the genetic architecture of grain size and weight in barley. We used a multi-parent population developed from a genetic cross between 23 diverse barley inbreds in a double round-robin design. Seed size-related parameters such as grain length, grain width, grain area and thousand-grain weight were evaluated in the HvDRR population comprising 45 recombinant inbred line sub-populations. We found significant genotypic variation for all seed size characteristics, and observed 84% or higher heritability across four environments. The quantitative trait locus (QTL) detection results indicate that the genetic architecture of grain size is more complex than previously reported. In addition, both cultivars and landraces contributed positive alleles at grain size QTLs. Candidate genes identified using genome-wide variant calling data for all parental inbred lines indicated overlapping and potential novel regulators of grain size in cereals. Furthermore, our results indicated that sink capacity was the primary determinant of grain weight in barley.
MLL1:EZH2 Ratio in Uterine Secretions and Endometrial Receptivity in Patients with Endometriosis
Authors: Zou Kehan , Du Qing , Chen Xin , Tang Pingfang , Liang Huizhen
Published: September 2022

Objective

To establish a novel approach for diagnosing endometriosis (EM) in patients with impaired endometrial receptivity.

Method

Mixed lineage leukemia 1 (MLL1) and enhancer of zeste homolog 2 (EZH2) levels were analyzed. The MLL1:EZH2 ratio in identifying impaired endometrial receptivity has been established and validated.

Results

In normal endometrial tissue, the MLL1:EZH2 ratio increased significantly in the midsecretory phase, compared with that in the proliferative phase. In the midsecretory phase, the MLL1:EZH2 ratio in endometrial tissues and uterine secretions accurately identifies patients with EM who have impaired endometrial receptivity. In the validation group, the sensitivity and specificity of the MLL1:EZH2 ratio in the uterine secretions of the midsecretory phase, in diagnosing patients EM who have impaired endometrial receptivity, were 100% and 96.55%, respectively.

Conclusions

The MLL1:EZH2 ratio in uterine secretions of the midsecretory phase may serve as a marker to diagnose EM in patients with impaired endometrial receptivity.
Collimation of the kiloparsec-scale radio jets in NGC 2663
Authors: Velović Velibor , Filipović M D , Barnes L , Norris R P , Tremblay C D , Heald G , Rudnick L , Shabala S S , Pannuti T G , Andernach H , Titov O , Waddell S G H , Koribalski B S , Grupe D , Jarrett T , Alsaberi R Z E , Carretti E , Collier J D , Einecke S , Galvin T J , Hotan A , Manojlović P , Marvil J , Nandra K , Reiprich T H , Rowell G , Salvato M , Whiting M
Published: September 2022

We present the discovery of highly collimated radio jets spanning a total of 355 kpc around the nearby elliptical galaxy NGC 2663, and the possible first detection of recollimation on kiloparsec scales. The small distance to the galaxy (∼28.5 Mpc) allows us to resolve portions of the jets to examine their structure. We combine multiwavelength data: radio observations by the Murchison Widefield Array (MWA), the Australian Square Kilometre Array Pathfinder (ASKAP) and the Australia Telescope Compact Array (ATCA), and X-ray data from Chandra, Swift, and SRG/eROSITA. We present intensity, rotation measure, polarization, spectral index, and X-ray environment maps. Regions of the southern jet show simultaneous narrowing and brightening, which can be interpreted as a signature of the recollimation of the jet by external, environmental pressure, though it is also consistent with intermittent active galactic nuclei or complex internal jet structure. X-ray data suggest that the environment is extremely poor; if the jet is indeed recollimating, the large recollimation scale (40 kpc) is consistent with a slow jet in a low-density environment.
The hydrogen clock to infer the upper stellar mass
Authors: Higgins Erin R , Vink Jorick S , Sabhahit Gautham N , Sander Andreas A C
Published: September 2022

The most massive stars dominate the chemical enrichment, mechanical and radiative feedback, and energy budget of their host environments. Yet how massive stars initially form and how they evolve throughout their lives is ambiguous. The mass loss of the most massive stars remains a key unknown in stellar physics, with consequences for stellar feedback and populations. In this work, we compare grids of very massive star (VMS) models with masses ranging from 80 to 1000 M⊙, for a range of input physics. We include enhanced winds close to the Eddington limit as a comparison to standard O-star winds, with consequences for present-day observations of ∼50–100 M⊙ stars. We probe the relevant surface H abundances (Xs) to determine the key traits of VMS evolution compared to O stars. We find fundamental differences in the behaviour of our models with the enhanced-wind prescription, with a convergence on the stellar mass at 1.6 Myr, regardless of the initial mass. It turns out that Xs is an important tool in deciphering the initial mass due to the chemically homogeneous nature of VMS above a mass threshold. We use Xs to break the degeneracy of the initial masses of both components of a detached binary, and a sample of WNh stars in the Tarantula Nebula. We find that for some objects, the initial masses are unrestricted and, as such, even initial masses of the order 1000 M⊙ are not excluded. Coupled with the mass turnover at 1.6 Myr, Xs can be used as a ‘clock’ to determine the upper stellar mass.
First Light and Reionisation Epoch Simulations (FLARES) – VI. The colour evolution of galaxies z = 5–15
Authors: Wilkins Stephen M , Vijayan Aswin P , Lovell Christopher C , Roper William J , Irodotou Dimitrios , Caruana Joseph , Seeyave Louise T C , Kuusisto Jussi K , Thomas Peter A
Published: September 2022

With its exquisite sensitivity, wavelength coverage, and spatial and spectral resolution, the James Webb Space Telescope (JWST) is poised to revolutionize our view of the distant, high-redshift (z > 5) Universe. While Webb’s spectroscopic observations will be transformative for the field, photometric observations play a key role in identifying distant objects and providing more comprehensive samples than accessible to spectroscopy alone. In addition to identifying objects, photometric observations can also be used to infer physical properties and thus be used to constrain galaxy formation models. However, inferred physical properties from broad-band photometric observations, particularly in the absence of spectroscopic redshifts, often have large uncertainties. With the development of new tools for forward modelling simulations, it is now routinely possible to predict observational quantities, enabling a direct comparison with observations. With this in mind, in this work, we make predictions for the colour evolution of galaxies at z = 5–15 using the First Light And Reionisation Epoch Simulations (flares) cosmological hydrodynamical simulation suite. We predict a complex evolution with time, driven predominantly by strong nebular line emission passing through individual bands. These predictions are in good agreement with existing constraints from Hubble and Spitzer as well as some of the first results from Webb. We also contrast our predictions with other models in the literature: While the general trends are similar, we find key differences, particularly in the strength of features associated with strong nebular line emission. This suggests photometric observations alone should provide useful discriminating power between different models and physical states of galaxies.
CO2-driven surface changes in the Hapi region on Comet 67P/Churyumov–Gerasimenko
Authors: Davidsson Björn J R , Schloerb F Peter , Fornasier Sonia , Oklay Nilda , Gutiérrez Pedro J , Buratti Bonnie J , Chmielewski Artur B , Gulkis Samuel , Hofstadter Mark D , Keller H Uwe , Sierks Holger , Güttler Carsten , Küppers Michael , Rickman Hans , Choukroun Mathieu , Lee Seungwon , Lellouch Emmanuel , Lethuillier Anthony , Da Deppo Vania , Groussin Olivier , Kührt Ekkehard , Thomas Nicolas , Tubiana Cecilia , El-Maarry M Ramy , La Forgia Fiorangela , Mottola Stefano , Pajola Maurizio
Published: September 2022

Between 2014 December 31 and 2015 March 17, the OSIRIS cameras on Rosetta documented the growth of a $140\, \mathrm{\hbox{-}m}$ wide and $0.5\, \mathrm{\hbox{-}m}$ deep depression in the Hapi region on Comet 67P/Churyumov–Gerasimenko. This shallow pit is one of several that later formed elsewhere on the comet, all in smooth terrain that primarily is the result of airfall of coma particles. We have compiled observations of this region in Hapi by the microwave instrument MIRO on Rosetta, acquired during October and November 2014. We use thermophysical and radiative transfer models in order to reproduce the MIRO observations. This allows us to place constraints on the thermal inertia, diffusivity, chemical composition, stratification, extinction coefficients, and scattering properties of the surface material, and how they evolved during the months prior to pit formation. The results are placed in context through long-term comet nucleus evolution modelling. We propose that (1) MIRO observes signatures that are consistent with a solid-state greenhouse effect in airfall material; (2) CO2 ice is sufficiently close to the surface to have a measurable effect on MIRO antenna temperatures, and likely is responsible for the pit formation in Hapi observed by OSIRIS; (3) the pressure at the CO2 sublimation front is sufficiently strong to expel dust and water ice outwards, and to compress comet material inwards, thereby causing the near-surface compaction observed by CONSERT, SESAME, and groundbased radar, manifested as the ‘consolidated terrain’ texture observed by OSIRIS.
A universal profile for stacked filaments from cold dark matter simulations
Authors: Yang Tianyi , Hudson Michael J , Afshordi Niayesh
Published: September 2022

We study the stacked filaments connecting group-mass halo pairs, using dark-matter-only N-body simulations. We calculate the dark matter overdensity profile of these stacked filaments at different redshifts as a function of the distance perpendicular to the filament axis. A four-parameter universal functional form, including three comoving scale radii and one amplitude parameter (core density), provides a good fit out to a radius of 20h−1cMpc for stacked filaments over a range of redshifts, lengths, and masses. The scale radii are approximately independent of redshift but increase as power laws with the comoving filament length. Lastly, we compare the scaling of the filament mass measured directly from the simulations to the predicted scaling from the halo–halo–matter three-point correlation function as a function of redshift and of the mass of the halo pairs. We find that both measured scalings are similar to, but somewhat shallower than the predictions, by 10 per cent and 30 per cent, respectively. These results provide a template to interpret present and upcoming observational results based on stacking, for example, weak lensing, thermal and kinetic Sunyaev-Zel’dovich, or X-ray observations.
The flickering radio jet from the quiescent black hole X-ray binary A0620-00
Authors: dePolo Donna L , Plotkin Richard M , Miller-Jones James C A , Strader Jay , Maccarone Thomas J , O’Doherty Tyrone N , Chomiuk Laura , Gallo Elena
Published: September 2022

Weakly accreting black hole X-ray binaries launch compact radio jets that persist even in the quiescent spectral state, at X-ray luminosities ≲ 10−5 of the Eddington luminosity. However, radio continuum emission has been detected from only a few of these quiescent systems, and little is known about their radio variability. Jet variability can lead to misclassification of accreting compact objects in quiescence, and affects the detectability of black hole X-ray binaries in next-generation radio surveys. Here we present the results of a radio monitoring campaign of A0620 − 00, one of the best-studied and least-luminous known quiescent black hole X-ray binaries. We observed A0620 − 00 at 9.8 GHz using the Karl G Jansky Very Large Array on 31 epochs from 2017 to 2020, detecting the source $\sim 75{{\ \rm per\, cent}}$ of the time. We see significant variability over all time-scales sampled, and the observed flux densities follow a lognormal distribution with μ = 12.5 μJy and σ = 0.22 dex. In no epoch was A0620 − 00 as bright as in 2005 (51 ± 7 μJy), implying either that this original detection was obtained during an unusually bright flare, or that the system is fading in the radio over time. We present tentative evidence that the quiescent radio emission from A0620 − 00 is less variable than that of V404 Cyg, the only other black hole binary with comparable data. Given that V404 Cyg has a jet radio luminosity ∼20 times higher than A0620 − 00, this comparison could suggest that less luminous jets are less variable in quiescence.
NEOSSat observations of three transiting hot Jupiters
Authors: Fox Chris , Wiegert Paul
Published: September 2022

The Near Earth Object Surveillance Satellite (NEOSSat) is a Canadian-led 15 cm Earth-orbiting telescope originally designed to detect asteroids near the Sun. Its design is however also suitable for the observation of exoplanetary transits of bright stars. We used the NEOSSat platform to perform followup observations of several Transiting Exoplanets Survey Satellite (TESS) targets, both as a demonstration of NEOSSat capabilities for exoplanetary science and improve the orbital ephemerides and properties of these exoplanet systems. We are able to recover / confirm the orbital properties of such targets to within mutual error bars, demonstrating NEOSSat as a useful future contributor to exoplanetary science.
Generalized model-independent characterization of strong gravitational lenses VIII. Automated multiband feature detection to constrain local lens properties
Authors: Lin Joyce , Wagner Jenny , Griffiths Richard E
Published: September 2022

As established in previous papers of this series, observables in highly distorted and magnified multiple images caused by the strong gravitational lensing effect can be used to constrain the distorting properties of the gravitational lens at the image positions. If the background source is extended and contains substructure, like star forming regions, which is resolved in multiple images, all substructure that can be matched across a minimum of three multiple images can be used to infer the local distorting properties of the lens. In this work, we replace the manual feature selection by an automated feature extraction based on SExtractor for Python and show its superior performance. Despite its aimed development to improve our lens reconstruction, it can be employed in any other approach, as well. Valuable insights on the definition of an ‘image position’ in the presence of noise are gained from our calibration tests. Applying it to observations of a five-image configuration in galaxy cluster CL0024 and the triple-image configuration containing Hamilton’s object, we determine local lens properties for multiple wavebands separately. Within current confidence bounds, all of them are consistent with each other, corroborating the wavelength-independence of strong lensing and offering a tool to detect deviations caused by micro-lensing and dust in further examples.
The orbital architecture and stability of the μ Arae planetary system
Authors: Goździewski K
Published: September 2022

We re-analyse the global orbital architecture and dynamical stability of the HD 160691 planetary system. We have updated the best-fitting elements and minimal masses of the planets based on literature precision radial velocity (RV) measurements, now spanning 17.3 yr. This is twice the RVs interval used for the first characterization of the system in 2006. It consists of a Saturn- and two Jupiter-mass planets in low-eccentric orbits resembling the Earth–Mars–Jupiter configuration in the Solar system, as well as the close-in warm Neptune with a mass of ≃14 Earth masses. Here, we constrain this early solution with the outermost period to be accurate to one month. The best-fitting Newtonian model is characterized by moderate eccentricities of the most massive planets below 0.1 with small uncertainties ≃0.02. It is close but meaningfully separated from the 2e:1b mean motion resonance of the Saturn–Jupiter-like pair, but may be close to weak three-body MMRs. The system appears rigorously stable over a wide region of parameter space covering uncertainties of several σ. The system stability is robust to a five-fold increase in the minimal masses, consistent with a wide range of inclinations, from ≃20° to 90°. This means that all planetary masses are safely below the brown dwarf mass limit. We found a weak statistical indication of the likely system inclination $I \simeq \, 20^{\circ }$–30°. Given the well-constrained orbital solution, we also investigate the structure of hypothetical debris discs, which are analogues of the Main Belt and Kuiper Belt, and may naturally occur in this system.
Magnetically confined mountains on accreting neutron stars with multipole magnetic fields
Authors: Fujisawa Kotaro , Kisaka Shota , Kojima Yasufumi
Published: September 2022

Magnetically confined mountains on accreting neutron stars are candidates for producing continuous gravitational waves. We formulate a magnetically confined mountain on a neutron star with strong multipole magnetic fields and obtain some sequences of numerical solutions. We find that the mass ellipticity of the mountain increases by one order of magnitude if the neutron star has strong multipole magnetic fields. As matter accretes on to the magnetic pole, the size of the mountain increases and the magnetic fields are buried. If the neutron star has a dipole magnetic field, the dipole magnetic field is buried and transformed into multipole components. By contrast, if the neutron star has both dipole and strong multipole magnetic fields, the multipole magnetic fields are buried and transformed into a negative dipole component. We also calculate magnetically confined mountains with toroidal magnetic fields and find that the ellipticity becomes slightly smaller when the mountain has toroidal magnetic fields. If the multipole magnetic fields are buried, they sustain the intense toroidal magnetic field near the stellar surface, and the ratio of the toroidal magnetic field to the poloidal magnetic field is close to 100. The hidden strong toroidal magnetic fields are sustained by the buried multipole magnetic fields.
Pre-explosion, explosion, and post-explosion jets in supernova SN 2019zrk
Authors: Soker Noam
Published: September 2022

I analyse some properties of the luminous transient event SN 2019zrk and conclude that jets were the main powering sources of the pre-explosion outburst (pre-cursor) and ejection of a massive circumstellar matter (CSM), of the very energetic explosion itself, and of the post-explosion bump in the light curve. The pre-explosion energy source is mainly a companion (main sequence, Wolf–Rayet, neutron star, or black hole) star that accreted mass and launched jets. I find that the fast expansion of the CSM after acceleration by the explosion ejecta requires the explosion energy to be $\gtrsim 10^{52}\, {~\rm erg}$. Only jet-driven explosions can supply this energy in such SN 2009ip-like transients. I conclude that ejecta-CSM interaction is extremely unlikely to power the bright bump at about 110 d after explosion. Instead, I show by applying a jet-driven bump toy-model that post-explosion jets are the most likely explanation for the bump. I leave open the question of whether the explosion itself (main outburst) was a core collapse supernova (CCSN) or a common envelope jets supernova (CEJSN). In this study, I further connect peculiar transient events, here 2009ip-like transient events, to CCSNe by arguing that jets drive all events, from regular CCSNe through superluminous CCSNe and to many other peculiar and superenergetic transient events, including CEJSNe. Jet-powering cannot be ignored when analysing all these types of transients.
Measuring the Hubble constant with double gravitational wave sources in pulsar timing
Authors: McGrath Casey , D’Orazio Daniel J , Creighton Jolien
Published: September 2022

Pulsar timing arrays (PTAs) are searching for gravitational waves from supermassive black hole binaries (SMBHBs). Here we show how future PTAs could use a detection of gravitational waves from individually resolved SMBHB sources to produce a purely gravitational wave-based measurement of the Hubble constant. This is achieved by measuring two separate distances to the same source from the gravitational wave signal in the timing residual: the luminosity distance DL through frequency evolution effects, and the parallax distance Dpar through wavefront curvature (Fresnel) effects. We present a generalized timing residual model including these effects in an expanding universe. Of these two distances, Dpar is challenging to measure due to the pulsar distance wrapping problem, a degeneracy in the Earth-pulsar distance and gravitational wave source parameters that requires highly precise, sub-parsec level, pulsar distance measurements to overcome. However, in this paper we demonstrate that combining the knowledge of two SMBHB sources in the timing residual largely removes the wrapping cycle degeneracy. Two sources simultaneously calibrate the PTA by identifying the distances to the pulsars, which is useful in its own right, and allow recovery of the source luminosity and parallax distances which results in a measurement of the Hubble constant. We find that, with optimistic PTAs in the era of the Square Kilometre Array, two fortuitous SMBHB sources within a few hundred Mpc could be used to measure the Hubble constant with a relative uncertainty on the order of 10 per cent.
Gaussian process model for the local stellar velocity field from Gaia data release 2
Authors: Nelson Patrick , Widrow Lawrence M
Published: September 2022

We model the local stellar velocity field using position and velocity measurements for 4M stars from the second data release of Gaia. We determine the components of the mean or bulk velocity in $\sim 27\, 000$ spatially defined bins. Our assumption is that these quantities constitute a Gaussian process where the correlation between the bulk velocity at different locations is described by a simple covariance function or kernel. We use a sparse Gaussian process algorithm based on inducing points to construct a non-parametric, smooth, and differentiable model for the underlying mean stellar velocity field. We estimate the Oort constants A, B, C, and K and find values in excellent agreement with previous results. Maps of the velocity field within $2\, {\rm kpc}$ of the Sun reveal complicated substructures, which provide clear evidence that the local disc is in a state of disequilibrium. We present the first three-dimensional map of the divergence of the stellar velocity field and identify regions of the disc that may be undergoing compression and rarefaction.