bluuebunny/crossref_metadata_2025 huggingface dataset:
Local genetic covariance between serum urate and kidney function estimated with Bayesian multitrait models
Authors: Lupi Alexa S , Sumpter Nicholas A , Leask Megan P , O’Sullivan Justin , Fadason Tayaza , de los Campos Gustavo , Merriman Tony R , Reynolds Richard J , Vazquez Ana I
Published: July 2022

Hyperuricemia (serum urate >6.8 mg/dl) is associated with several cardiometabolic and renal diseases, such as gout and chronic kidney disease. Previous studies have examined the shared genetic basis of chronic kidney disease and hyperuricemia in humans either using single-variant tests or estimating whole-genome genetic correlations between the traits. Individual variants typically explain a small fraction of the genetic correlation between traits, thus the ability to map pleiotropic loci is lacking power for available sample sizes. Alternatively, whole-genome estimates of genetic correlation indicate a moderate correlation between these traits. While useful to explain the comorbidity of these traits, whole-genome genetic correlation estimates do not shed light on what regions may be implicated in the shared genetic basis of traits. Therefore, to fill the gap between these two approaches, we used local Bayesian multitrait models to estimate the genetic covariance between a marker for chronic kidney disease (estimated glomerular filtration rate) and serum urate in specific genomic regions. We identified 134 overlapping linkage disequilibrium windows with statistically significant covariance estimates, 49 of which had positive directionalities, and 85 negative directionalities, the latter being consistent with that of the overall genetic covariance. The 134 significant windows condensed to 64 genetically distinct shared loci which validate 17 previously identified shared loci with consistent directionality and revealed 22 novel pleiotropic genes. Finally, to examine potential biological mechanisms for these shared loci, we have identified a subset of the genomic windows that are associated with gene expression using colocalization analyses. The regions identified by our local Bayesian multitrait model approach may help explain the association between chronic kidney disease and hyperuricemia.
Spatial and temporal control of expression with light-gated LOV-LexA
Authors: Ribeiro Inês M A , Eßbauer Wolfgang , Kutlesa Romina , Borst Alexander
Published: July 2022

The ability to drive expression of exogenous genes in different tissues and cell types, under the control of specific enhancers, has been crucial for discovery in biology. While many enhancers drive expression broadly, several genetic tools were developed to obtain access to isolated cell types. Studies of spatially organized neuropiles in the central nervous system of fruit flies have raised the need for a system that targets subsets of cells within a single neuronal type, a feat currently dependent on stochastic flip-out methods. To access the same cells within a given expression pattern consistently across fruit flies, we developed the light-gated expression system LOV-LexA. We combined the bacterial LexA transcription factor with the plant-derived light, oxygen, or voltage photosensitive domain and a fluorescent protein. Exposure to blue light uncages a nuclear localizing signal in the C-terminal of the light, oxygen, or voltage domain and leads to the translocation of LOV-LexA to the nucleus, with the subsequent initiation of transcription. LOV-LexA enables spatial and temporal control of expression of transgenes under LexAop sequences in larval fat body and pupal and adult neurons with blue light. The LOV-LexA tool is ready to use with GAL4 and Split-GAL4 drivers in its current form and constitutes another layer of intersectional genetics that provides light-controlled genetic access to specific cells across flies.
Neuropsychological Correlates of Changes in Driving Behavior Among Clinically Healthy Older Adults
Authors: Aschenbrenner Andrew J , Murphy Samantha A , Doherty Jason M , Johnson Ann M , Bayat Sayeh , Walker Alexis , Peña Yasmin , Hassenstab Jason , Morris John C , Babulal Ganesh M
Published: July 2022

Objectives

To determine the extent to which cognitive domain scores moderate change in driving behavior in cognitively healthy older adults using naturalistic (Global Positioning System-based) driving outcomes and to compare against self-reported outcomes using an established driving questionnaire.

Methods

We analyzed longitudinal naturalistic driving behavior from a sample (N = 161, 45% female, mean age = 74.7 years, mean education = 16.5 years) of cognitively healthy, nondemented older adults. Composite driving variables were formed that indexed “driving space” and “driving performance.” All participants completed a baseline comprehensive cognitive assessment that measured multiple domains as well as an annual self-reported driving outcomes questionnaire.

Results

Across an average of 24 months of naturalistic driving, our results showed that attentional control, broadly defined as the ability to focus on relevant aspects of the environment and ignore distracting or competing information as measured behaviorally with tasks such as the Stroop color naming test, moderated change in driving space scores over time. Specifically, individuals with lower attentional control scores drove fewer trips per month, drove less at night, visited fewer unique locations, and drove in smaller spaces than those with higher attentional control scores. No cognitive domain predicted driving performance such as hard braking or sudden acceleration.

Discussion

Attentional control is a key moderator of change over time in driving space but not driving performance in older adults. We speculate on mechanisms that may relate attentional control ability to modifications of driving behaviors.
Enhanced volatile emissions and anti-herbivore functions mediated by the synergism between jasmonic acid and salicylic acid pathways in tea plants
Authors: Jiao Long , Bian Lei , Luo Zongxiu , Li Zhaoqun , Xiu Chunli , Fu Nanxia , Cai Xiaoming , Chen Zongmao
Published: July 2022

The interaction between jasmonic acid (JA) and salicylic acid (SA) pathways, which affects plant stress resistance, is mainly considered to be antagonistic. Using an established theoretical model, we investigated how tea plant (Camellia sinensis) volatiles induced by exogenous elicitors of the JA and SA pathways are affected by the sequence of elicitor application, elicitor identity, and the applied concentrations. We also examined the effects of the volatiles mediated by the JA–SA synergistic interaction on the behaviors of a tea leaf-chewing herbivore (Ectropis grisescens) and its parasitic wasp (Apanteles sp.). The JA and SA pathway interactions were almost always reciprocally synergistic when the two pathways were elicited at different times, except at high JA elicitor concentrations. However, the JA pathway antagonized the SA pathway when they were elicited simultaneously. The elicitor identity affected the degree of JA–SA interaction. The volatiles induced by the JA pathway in the JA–SA reciprocal synergism treatments included up to 11 additional compounds and the total amount of volatiles was up to 7.9-fold higher. Similarly, the amount of emitted volatiles induced by the SA pathway in the reciprocal synergism treatments increased by up to 4.2-fold. Compared with the volatiles induced by either pathway, the enriched volatiles induced by the JA–SA reciprocal synergism similarly repelled E. grisescens, but attracted Apanteles sp. more strongly. Thus, non-simultaneous activation is important for optimizing the JA–SA reciprocal synergism. This reciprocal synergism enables plants to induce multifarious responses, leading to increased biotic stress resistance.
Susceptibility factor StEXA1 interacts with StnCBP to facilitate potato virus Y accumulation through the stress granule-dependent RNA regulatory pathway in potato
Authors: Chen Ruhao , Tu Zhen , He Changzheng , Nie Xianzhou , Li Kun , Fei Sitian , Song Botao , Nie Bihua , Xie Conghua
Published: July 2022

Plant viruses recruit multiple host factors for translation, replication, and movement in the infection process. The loss-of-function mutation of the susceptibility genes will lead to the loss of susceptibility to viruses, which is referred to as ‘recessive resistance’. Essential for potexvirus Accumulation 1 (EXA1) has been identified as a susceptibility gene required for potexvirus, lolavirus, and bacterial and oomycete pathogens. In this study, EXA1 knockdown in potato (StEXA1) was found to confer novel resistance to potato virus Y (PVY, potyvirus) in a strain-specific manner. It significantly compromised PVYO accumulation but not PVYN:O and PVYNTN. Further analysis revealed that StEXA1 is associated with the HC-Pro of PVY through a member of eIF4Es (StnCBP). HC-ProO and HC-ProN, two HC-Pro proteins from PVYO and PVYN, exhibited strong and weak interactions with StnCBP, respectively, due to their different spatial conformation. Moreover, the accumulation of PVYO was mainly dependent on the stress granules (SGs) induced by StEXA1 and StnCBP, whereas PVYN:O and PVYNTN could induce SGs by HC-ProN independently through an unknown mechanism. These results could explain why StEXA1 or StnCBP knockdown conferred resistance to PVYO but not to PVYN:O and PVYNTN. In summary, our results for the first time demonstrate that EXA1 can act as a susceptibility gene for PVY infection. Finally, a hypothetical model was proposed for understanding the mechanism by which StEXA1 interacts with StnCBP to facilitate PVY accumulation in potato through the SG-dependent RNA regulatory pathway.
Microbe-assisted crop improvement: a sustainable weapon to restore holobiont functionality and resilience
Authors: Marco Sandrini , Loredana Moffa , Riccardo Velasco , Raffaella Balestrini , Walter Chitarra , Luca Nerva
Published: July 2022

In the past years, breeding programs have been mainly addressed on pushing the commercial features, forgetting important traits, such as those related to environmental stress resilience, that are instead present in wild relatives. Among the traits neglected by breeding processes, the ability to recruit beneficial microorganisms that recently is receiving a growing attention due to its potentiality. In this context, this review will provide a spotlight on critical issues of the anthropocentric point of view that, until now, has characterized the selection of elite plant genotypes. Its effects on the plant-microbiome interactions, and the possibility to develop novel strategies mediated by the exploitation of beneficial root-microbe interactions, will be discussed. More sustainable microbial-assisted strategies might in fact foster the green revolution and the achievement of a more sustainable agriculture in a climatic change scenario.
HsfA1a confers pollen thermotolerance through upregulating antioxidant capacity, protein repair, and degradation in Solanum lycopersicum L.
Authors: Xie Dong-Ling , Huang Hua-Min , Zhou Can-Yu , Liu Chen-Xu , Kanwar Mukesh Kumar , Qi Zhen-Yu , Zhou Jie
Published: July 2022

The heat shock transcription factors (Hsfs) play critical roles in plant responses to abiotic stresses. However, the mechanism of Hsfs in the regulation of pollen thermotolerance and their specific biological functions and signaling remain unclear. Herein, we demonstrate that HsfA1a played a key role in tomato pollen thermotolerance. Pollen thermotolerance was reduced in hsfA1a mutants but was increased by hsfA1a overexpression, based on pollen viability and germination. Analyzing the whole transcriptome by RNA-seq data, we found that HsfA1a mainly regulated the genes involved in oxidative stress protection, protein homeostasis regulation and protein modification, as well as the response to biological stress in anthers under heat stress. The accumulation of reactive oxygen species in anthers was enhanced in hsfA1a mutants but decreased in HsfA1a-overexpressing lines. Furthermore, HsfA1a bound to the promoter region of genes involved in redox regulation (Cu/Zn-SOD, GST8, and MDAR1), protein repair (HSP17.6A, HSP70-2, HSP90-2, and HSP101) and degradation (UBP5, UBP18, RPN10a, and ATG10) and regulated the expression of these genes in tomato anthers under heat stress. Our findings suggest that HsfA1a maintains pollen thermotolerance and cellular homeostasis by enhancing antioxidant capacity and protein repair and degradation, ultimately improving pollen viability and fertility.
Environmental and anthropogenic driven transitions in the demersal ecosystem of Cantabrian Sea
Authors: Polo J , Punzón A , Vasilakopoulos P , Somavilla R , Hidalgo M
Published: July 2022

In the framework of global human-induced change, marine communities’ often respond to changing conditions abruptly reorganizing into new equilibria. These shifts are difficult to predict and often imply irreversible adjustments due to hysteresis. Unraveling the role of the forces leading regime shifts is a major challenge. We explored the temporal evolution of 63 fish species representing the Cantabrian bentho-demersal community in response to environmental changes and fishing pressure in the period 1983–2018, using survey data. Via multivariate analysis and non-additive modeling of a community index and the system's main stressors, two decadal-scale regimes were revealed, suggesting a non-linear response of the community to its environment. The Integrated Resilience Assessment framework elucidated the response mechanism to the candidate stressors and allowed quantifying resilience dynamics. The decline in fishing pressure in the 1990s was associated with a gradual transition of the system, while further decline during the 2000s eroded the resilience of the system towards changes in its stressors, leading to a discontinuous response expressed as an abrupt, possibly irreversible shift in the 2010s. Given the teleconnected character of marine ecosystems, this regional study endorses the scientific effort for actions facing the dynamic impacts of climate change on exploited marine ecosystems.
How Effective Is Private Dispute Resolution? Evidence From Ireland
Authors: Roche William K
Published: July 2022

This article examines the effectiveness of private dispute resolution arrangements (PDRAs) established voluntarily by employers and unions in private- and public-sector firms and agencies in Ireland. PDRAs comprise three-person panels or sole adjudicators and combine binding or non-binding adjudication with internal mediation. PDRAs seek to rewrite the established rules and conventions governing dispute resolution within workplaces and to change the ways in which internal dispute resolution is aligned with external dispute resolution by state agencies. The majority of the eleven PDRAs examined are shown to be effective. One is described as ‘semi-dormant’ and two are shown to be less effective. Variations in the effectiveness of PDRAs are attributed to features of the internal and external contexts of the firms and agencies in which they have been established: the persistence of significant commercial and industrial relations challenges; the absence of disjunctures in organisations or industrial relations; the presence of champions; and the effects of industrial relations legacies. The paper contributes to the literature by systematically accounting for variations in the effectiveness of adjudication and arbitrations arrangements and concludes by considering whether the incidence of PDRAs is likely to continue rising.
Current clinical practice in antibiotic treatment of Staphylococcus aureus bacteraemia: results from a survey in five European countries
Authors: Buis D T P , Prins J M , Betica-Radic L , de Boer M G J , Ekkelenkamp M , Kofteridis D , Peiffer-Smadja N , Schouten J , Spernovasilis N , Tattevin P , ten Oever J , Sigaloff K C E
Published: July 2022

Objectives

To determine clinical practice variation and identify knowledge gaps in antibiotic treatment of Staphylococcus aureus bacteraemia (SAB).

Methods

A web-based survey with questions addressing antibiotic treatment of SAB was distributed through the ESGAP network among infectious disease specialists, clinical microbiologists and internists in Croatia, France, Greece, the Netherlands and the UK between July 2021 and November 2021.

Results

A total number of 1687 respondents opened the survey link, of whom 677 (40%) answered at least one question. For MSSA and MRSA bacteraemia, 98% and 94% preferred initial monotherapy, respectively. In patients with SAB and non-removable infected prosthetic material, between 80% and 90% would use rifampicin as part of the treatment. For bone and joint infections, 65%–77% of respondents would consider oral step-down therapy, but for endovascular infections only 12%–32% would. Respondents recommended widely varying treatment durations for SAB with different foci of infection. Overall, 48% stated they used 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG-PET/CT) to guide antibiotic treatment duration. Persistent bacteraemia was the only risk factor for complicated SAB that would prompt a majority to extend treatment from 2 to 4–6 weeks.

Conclusions

This survey in five European countries shows considerable clinical practice variation between and within countries in the antibiotic management of SAB, in particular regarding oral step-down therapy, choice of oral antibiotic agents, treatment duration and use of 18F-FDG-PET/CT. Physicians use varying criteria for treatment decisions, as evidence from clinical trials is often lacking. These areas of practice variation could be used to prioritize future studies for further improvement of SAB care.
Optimization of antimicrobial dosing in patients with acute kidney injury: a single-centre observational study
Authors: Hughes Stephen , Heard Katie L , Mughal Nabeela , Moore Luke S P
Published: July 2022

Background

Acute kidney injury (AKI) is a potential complication of systemic infection. Optimizing antimicrobial dosing in this dynamic state can be challenging with sub- or supra-therapeutic dosing risking treatment failure or toxicity, respectively. Locally, unadjusted renal dosing for the first 48 h of infection is recommended.

Objectives

To determine the outcomes associated with this dosing strategy.

Methods

A retrospective cohort analysis was undertaken in patients treated for Gram-negative bacteraemia with concurrent non-filtration dependent AKI from a single-centre NHS acute hospital (April 2016–March 2020). Patient demographics, microbiology data, antimicrobial treatment and patient outcome (in-hospital mortality and kidney function) were analysed.

Results

In total, 647 episodes of Gram-negative bacteraemia (608 patients) were included; 305/608 (50.2%) were male with median age 71 years (range 18–100). AKI was present in 235/647 (36.3%); 78/647 (12.1%) and 45/647 (7.0%) having Kidney Disease Improving Global Outcomes-defined injury (stage 2) or failure (stage 3), respectively. In-hospital 30 day mortality was 25/352 (7.1%), 14/112 (12.5%), 26/123 (21.1%) and 11/60(18.3%) in patients with normal renal function, AKI stage 1, AKI stage ≥2 and established chronic kidney disease, respectively. Recovery of renal function at Day 21 or discharge was present in 105/106 surviving patients presenting with AKI stage ≥2. Time to recovery of AKI was similar in patients receiving full, low or no aminoglycoside (3 versus 4 versus 3 days, P = 0.612) and those receiving full- and low-dose β-lactam (3 versus 5 days, P = 0.077).

Conclusions

There is a high burden of AKI in patients with Gram-negative bacteraemia. Dose adjustments of β-lactams may not be necessary in the first 48 h of infection-induced AKI and single-dose aminoglycosides may be considered for early empirical coverage.
Automation of crane control for block lifting based on deep reinforcement learning
Authors: Chun Do-Hyun , Roh Myung-Il , Lee Hye-Won
Published: July 2022

In shipyards, blocks are controlled by connecting the crane and block with wires during block erection. During block lifting, if a block is not carefully controlled, it will cause damage. Block lifting using crane operation is performed by controlling the number of wires, hooks, and equalizers. Consequently, predicting stable block lifting is difficult. In this study, we proposed a control method to determine static equilibrium. Initially, an algorithm for finding the initial equilibrium state of the block (IES algorithm) was proposed, followed by deep reinforcement learning (DRL)-based method for block lifting. The position, orientation, angular velocity of the block, and hoisting speed of the wires were applied as the DRL state. The control input of the crane was calculated by deriving the hoisting speed of the wires. To verify the proposed method, comparative studies on the application of the IES algorithm were carried out, and further block movement was compared. Conclusively, the proposed method effectively increased block lifting safety.
The Complexities of Comparative Climate Constitutionalism
Authors: Ghaleigh Navraj Singh , Setzer Joana , Welikala Asanga
Published: July 2022

Climate constitutionalism is a relatively novel legal field that has nonetheless adopted a very distinct character. Picking up on the classical liberal tack, it is marked by a distrust of state power as it relates to climate action or inaction. This is a venerable approach. In his 1967 classic, MJC Vile recounts that the ‘great theme of the advocates of constitutionalism [had been] the frank acknowledgement of the role of government in society, linked with the determination to bring that government under control and to place limits on the exercise of its power’. This mode of distrust has been ported to the climate constitutionalism literature and in particular its focus on adjudication of constitutional rights provisions for climate purposes. This, we argue, is but one aspect of climate constitutionalism that no longer speaks to the needs of the world when we think about the relationship between climate change, the doctrines and institutions of comparative constitutional law, and the underpinning theory of constitutionalism for this relationship. The institutional dimension of the constitutional management of climate change must go beyond courts and rights to processes and institutions in the two political branches of the state. The normative theory of climate constitutionalism—why should climate change be a constitutional subject on a global scale?—should address itself to the matter of how that question can be answered from a wider and more pluralistic set of normative standpoints than simply only liberalism. In other words, how can climate constitutionalism be normatively justified beyond, although not against, liberalism?
Counting when, who and how
Authors: MacDonald Isobel
Published: July 2022

This paper critically examines the possibilities of using the British Museum’s collection database as a research tool to examine acquisition history. It publishes initial findings from the author’s research into the history of the collection through a quantitative analysis of collection data. Rather than focusing on individual collectors, collections or areas of the collection, it takes a high-level comprehensive view of the current body of material, across time, departments and material. The paper asks three questions of the database: when did objects enter the museum’s collection, from whom and how? Through a numerical analysis, acquisition patterns are revealed which both challenge and augment our understanding of the history of the collection.
Acute appendicitis in the context of De Garengeot hernia: a case report
Authors: Shellman Zachary , Worku Dawit , Kulkarni Nikhil
Published: July 2022

De Garengeot hernia is a rare type of hernia so called when the vermiform appendix is found within the hernia sac of a femoral hernia. For the appendix to be inflamed is yet more uncommon. We present the case of a 61-year-old man who presented with a painful right groin lump. Computed tomography imaging reported an inguinal hernia containing a non-inflamed appendix however, intraoperative findings confirmed a femoral hernia containing an appendix with a necrotic tip. As such, these cases prove a diagnostic challenge as not only are the clinical findings illusive, but the radiological findings are often misleading. Diagnosis is often intraoperative and case reports such as this are useful in highlighting this challenging pathology.
A stubborn nasogastric tube: self-knotting of a nasogastric tube
Authors: Tsandiraki Justin , Tendai Joylene , Likiliwike Arnold D , Moirana Ezekiel N , Msuya David , Tarmohamed Murad
Published: July 2022

Nasogastric tubes (NGT) are widely used and generally harmless as such, complications are uncommon. NGT knotting is one such complication. We report a 45-month-old female with spontaneously knotted NGT that was identified and safely removed without complications. NGT knotting detection needs a high index of suspicion; if not detected and managed in a proper way, it may lead to severe complications. We discuss this case to raise awareness of this complication and how to minimize the likelihood of it happening and improve patient outcome.
Cross-correlation between Planck CMB lensing potential and galaxy catalogues from HELP
Authors: Saraf Chandra Shekhar , Bielewicz P , Chodorowski M
Published: July 2022

We present the study of cross-correlation between Cosmic Microwave Background (CMB) gravitational lensing potential map released by the Planck collaboration and photometric redshift galaxy catalogues from the Herschel Extragalactic Legacy Project (HELP), divided into four sky patches: NGP, Herschel Stripe-82, and two halves of SGP field, covering in total ∼660 deg2 of the sky. We estimate the galaxy linear bias parameter, b0, from joint analysis of cross-power spectrum and galaxy autopower spectrum using Maximum Likelihood Estimation technique to obtain values ranging from 0.70 ± 0.01 for SGP Part-2 to 1.02 ± 0.02 for SGP Part-1 field. We also estimate the amplitude of cross-correlation and find the values spanning from 0.67 ± 0.18 for SGP Part-2 to 0.80 ± 0.23 for SGP Part-1 field, respectively. For NGP and SGP Part-1 fields, the amplitude is consistent with the expected value for the standard cosmological model within $\sim 1\, \sigma$, while for Herschel Stripe-82 and SGP Part-2, we find the amplitude to be smaller than expected with $\sim 1.5\, \sigma$ and $\sim 2\, \sigma$ deviation, respectively. We perform several tests on various systematic errors to study the reason for the deviation, however, value of the amplitude turns out to be robust with respect to these errors. The only significant change in the amplitude is observed when we replace the minimum-variance CMB lensing map, used in the baseline analysis, by the lensing map derived from the CMB temperature map with deprojected thermal Sunyaev–Zeldovich signal.
Emergence of a new H i 21-cm absorption component at z ∼ 1.1726 towards the γ-ray blazar PKS 2355-106
Authors: Srianand Raghunathan , Gupta Neeraj , Petitjean Patrick , Momjian Emmanuel , Balashev Sergei A , Combes Françoise , Chen Hsiao-Wen , Krogager Jens-Kristian , Noterdaeme Pasquier , Rahmani Hadi , Baker Andrew J , Emig Kimberly L , Józsa Gyula I G , Kloeckner Hans-Rainer , Moodley Kavilan
Published: July 2022

We report the emergence of a new H i 21-cm absorption at zabs = 1.172 635 in the damped Lyα absorber (DLA) towards the γ-ray blazar PKS 2355-106 (zem∼1.639) using science verification observations (2020 June) from the MeerKAT Absorption Line Survey (MALS). Since 2006, this DLA is known to show a narrow H i 21-cm absorption at zabs = 1.173019 coinciding with a distinct metal absorption-line component. We do not detect significant H i 21-cm optical depth variations from this known H i component. A high-resolution optical spectrum (2010 August) shows a distinct Mg i absorption at the redshift of the new H i 21-cm absorber. However, this component is not evident in the profiles of singly ionized species. We measure the metallicity ([Zn/H] = −(0.77 ± 0.11) and [Si/H]= −(0.96 ± 0.11)) and depletion ([Fe/Zn] = −(0.63 ± 0.16)) for the full system. Using the apparent column density profiles of Si ii, Fe ii, and Mg i, we show that the depletion and the N(Mg i)/N(Si ii) column density ratio systematically vary across the velocity range. The region with high depletion tends to have a slightly larger N(Mg i)/N(Si ii) ratio. The two H i 21-cm absorbers belong to this velocity range. The emergence of zabs = 1.172 635 can be understood if there is a large optical depth gradient over a length-scale of ∼0.35 pc. However, the gas producing the zabs = 1.173 019 component must be nearly uniform over the same scale. Systematic uncertainties introduced by the absorption-line variability has to be accounted for in experiments measuring the variations of fundamental constants and cosmic acceleration even when the radio emission is apparently compact as in PKS 2355-106.
Quasar cosmology: dark energy evolution and spatial curvature
Authors: Bargiacchi G , Benetti M , Capozziello S , Lusso E , Risaliti G , Signorini M
Published: July 2022

We analyse some open debates in cosmology in light of the most updated quasar (QSO) sample, covering a wide redshift range up to $\mathit{ z}$ ∼ 7.5, combined with type Ia supernovae (SNe) and baryon acoustic oscillations (BAOs). Indeed, extending the cosmological analyses with high-redshift data is key to distinguishing between different cosmological models that are degenerate at low redshifts, and allowing better constraints on a possible dark energy (DE) evolution. Also, we discuss combinations of BAO, SNe, and QSO data to understand their compatibility and implications for extensions of the standard cosmological model. Specifically, we consider a flat and non-flat ΛCDM cosmology, a flat and non-flat DE model with a constant DE equation of state parameter (w), and four flat DE models with variable w, namely the Chevallier–Polarski–Linder and Jassal–Bagla–Padmanabhan models, and an ‘exponential’, and Barboza–Alcaniz parametrizations. We find that a joint analysis of QSO+SNe with BAO is only possible in the context of a flat Universe. Indeed BAO confirms the flatness condition assuming a curved geometry, whilst SNe + QSO show evidence of a closed space. We also find ΩM,0 = 0.3 in all data sets assuming a flat ΛCDM model. Yet, all the other models show a statistically significant deviation at 2-3 σ with the combined SNe + SO + BAO data set. In the models where DE density evolves with time, SNe + QSO + BAO data always prefer ΩM,0 > 0.3, w0 < −1 and wa > 0. This DE phantom behaviour is mainly driven by SNe + QSO, while BAO are closer to the flat ΛCDM model.
LyC escape from sphinx galaxies in the Epoch of Reionization
Authors: Rosdahl Joakim , Blaizot Jérémy , Katz Harley , Kimm Taysun , Garel Thibault , Haehnelt Martin , Keating Laura C , Martin-Alvarez Sergio , Michel-Dansac Léo , Ocvirk Pierre
Published: July 2022

We measure escape fractions, fesc, of ionizing radiation from galaxies in the sphinx suite of cosmological radiation-hydrodynamical simulations of reionization, resolving haloes with $M_{\rm vir}\gtrsim 7.5 \times 10^7 \ {\rm {M}_{\odot }}$ with a minimum cell width of ≈10 pc. Our new and largest 20 co-moving Mpc wide volume contains tens of thousands of star-forming galaxies with halo masses up to a few times 1011 M⊙. The simulated galaxies agree well with observational constraints of the ultraviolet (UV) luminosity function in the Epoch of Reionization. The escape fraction fluctuates strongly in individual galaxies over time-scales of a few Myr, due to its regulation by supernova and radiation feedback, and at any given time a tiny fraction of star-forming galaxies emits a large fraction of the ionizing radiation escaping into the intergalactic medium. Statistically, fesc peaks in intermediate-mass, intermediate-brightness, and low-metallicity galaxies (M* ≈ 107 M⊙, M1500 ≈ −17, Z ≲ 5 × 10−3 Z⊙), dropping strongly for lower and higher masses, brighter and dimmer galaxies, and more metal-rich galaxies. The escape fraction correlates positively with both the short-term and long-term specific star formation rate. According to sphinx, galaxies too dim to be yet observed, with ${M_{1500}}\gtrsim -17$, provide about 55 per cent of the photons contributing to reionization. The global averaged fesc naturally decreases with decreasing redshift, as predicted by UV background models and low-redshift observations. This evolution is driven by decreasing specific star formation rates over cosmic time.
Arecibo observations of a burst storm from FRB 20121102A in 2016
Authors: Hewitt D M , Snelders M P , Hessels J W T , Nimmo K , Jahns J N , Spitler L G , Gourdji K , Hilmarsson G H , Michilli D , Ould-Boukattine O S , Scholz P , Seymour A D
Published: July 2022

FRB 20121102A is the first known fast radio burst (FRB) from which repeat bursts were detected, and one of the best-studied FRB sources in the literature. Here we report on the analysis of 478 bursts (333 previously unreported) from FRB 20121102A using the 305-m Arecibo telescope – detected during approximately 59 hours of observations between December 2015 and October 2016. The majority of bursts are from a burst storm around September 2016. This is the earliest available sample of a large number of FRB 20121102A bursts, and it thus provides an anchor point for long-term studies of the source’s evolving properties. We observe that the bursts separate into two groups in the width-bandwidth-energy parameter space, which we refer to as the low-energy bursts (LEBs) and high-energy bursts (HEBs). The LEBs are typically longer duration and narrower bandwidth than the HEBs, reminiscent of the spectro-temporal differences observed between the bursts of repeating and non-repeating FRBs. We fit the cumulative burst rate-energy distribution with a broken power law and find that it flattens out toward higher energies. The sample shows a diverse zoo of burst morphologies. Notably, burst emission seems to be more common at the top than the bottom of our 1150–1730 MHz observing band. We also observe that bursts from the same day appear to be more similar to each other than to those of other days, but this observation requires confirmation. The wait times and burst rates that we measure are consistent with previous studies. We discuss these results, primarily in the context of magnetar models.
The viability of the optically thick wind model in accreting white dwarfs at high accretion rates
Authors: Cui Yingzhen , Meng Xiangcun
Published: July 2022

The single degenerate (SD) model is one of the leading models for the progenitors of Type Ia supernovae (SNe Ia). The optically thick wind (OTW) model is considered to be essential for the SD model. In this article, we aim to constrain the condition for the occurrence of the OTW. Using the stellar evolution code, Modules for Experiments in Stellar Astrophysics, we carried out a series of one-dimensional hydrodynamical simulations with different accretion rates and different white dwarf (WD) masses to simulate the dynamical ejection process on the accreting WDs. We find that, by neglecting interaction with the accreted material, we can get a similar result to the previous works using steady-state method, i.e. the OTW occurs. However, if we consider the interaction between the accreted and the outflowing materials, whether the OTW can occur or not becomes strongly dependent on the accretion rate. For a given WD mass, the higher the accretion rate, the less likely the OTW can occur. In addition, the WD masses can also affect the occurrence of the OTW, i.e. the higher the WD mass, the easier the OTW can occur. As a result, the OTW in novae may occur because the accretion rate is low enough, while in the SD progenitor system of SNe Ia, a high accretion rate is likely to prevent the occurrence of the OTW.
Dynamical fates of S-type planetary systems in embedded cluster environments
Authors: Ellithorpe Elizabeth A , Kaib Nathan A
Published: July 2022

The majority of binary star systems that host exoplanets will spend the first portion of their lives within a star-forming cluster that may drive dynamical evolution of the binary-planet system. We perform numerical simulations of S-type planets, with masses and orbital architecture analogous to the Solar system’s four gas giants, orbiting within the influence of a $0.5\, \mathrm{M}_{\odot }$ binary companion. The binary-planet system is integrated simultaneously with an embedded stellar cluster environment. ∼10 per cent of our planetary systems are destabilized when perturbations from our cluster environment drive the binary periastron towards the planets. This destabilization occurs despite all of our systems being initialized with binary orbits that would allow stable planets in the absence of the cluster. The planet–planet scattering triggered in our systems typically results in the loss of lower mass planets and the excitement of the eccentricities of surviving higher mass planets. Many of our planetary systems that go unstable also lose their binary companions prior to cluster dispersal and can therefore masquerade as hosts of eccentric exoplanets that have spent their entire histories as isolated stars. The cluster-driven binary orbital evolution in our simulations can also generate planetary systems with misaligned spin–orbit angles. This is typically done as the planetary system precesses as a rigid disc under the influence of an inclined binary, and those systems with the highest spin–orbit angles should often retain their binary companion and possess multiple surviving planets.
Extreme giant molecular clouds in the luminous infrared galaxy NGC 3256
Authors: Brunetti Nathan , Wilson Christine D
Published: July 2022

We present a cloud decomposition of 12CO (2–1) observations of the merger and nearest luminous infrared galaxy, NGC 3256. 185 spatially and spectrally resolved clouds are identified across the central ≈130 kpc2 at 90 pc resolution and completeness is estimated. We compare our cloud catalogue from NGC 3256 to ten galaxies observed in the PHANGS-ALMA survey. Distributions in NGC 3256 of cloud velocity dispersions (median 23 km s−1), luminosities (1.5 × 107 K km s−1 pc2), CO-estimated masses (2.1 × 107 M⊙), mass surface densities (470 M⊙ pc−2), virial masses (5.4 × 107 M⊙), virial parameters (4.3), size-linewidth coefficients (6.3 km2 s−2 pc−1), and internal turbulent pressures ( 1.0 × 10 7K cm−3$\, k_{\mathrm{B}}^{-1}$) are significantly higher than in the PHANGS-ALMA galaxies. Cloud radii (median 88 pc) are slightly larger in NGC 3256 and free-fall times (4.1 Myr) are shorter. The distribution of cloud eccentricities in NGC 3256 (median of 0.8) is indistinguishable from many PHANGS-ALMA galaxies, possibly because the dynamical state of clouds in NGC 3256 is similar to that of nearby spiral galaxies. However, the narrower distribution of virial parameters in NGC 3256 may reflect a narrower range of dynamical states than in PHANGS-ALMA galaxies. No clear picture of cloud alignment is detected, despite the large eccentricities. Correlations between cloud properties point to high external pressures in NGC 3256 keeping clouds bound and collapsing given such high velocity dispersions and star-formation rates. A fit to the cloud mass function gives a high-mass power-law slope of $-2.75^{+0.07}_{-0.01}$, near the average from PHANGS-ALMA galaxies. We also compare our results to a pixel-based analysis of these observations and find molecular-gas properties agree qualitatively, though peak brightness temperatures are somewhat higher and virial parameters and free-fall times are somewhat lower in this cloud-based analysis.
Redshift and stellar mass dependence of intrinsic shapes of disc-dominated galaxies from COSMOS observations below z = 1.0
Authors: Hoffmann K , Laigle C , Chisari N E , Tallada-Crespí P , Teyssier R , Dubois Y , Devriendt J
Published: July 2022

The high abundance of disc galaxies without a large central bulge challenges predictions of current hydrodynamic simulations of galaxy formation. We aim to shed light on the formation of these objects by studying the redshift and mass dependence of their intrinsic 3D shape distributions in the COSMOS galaxy survey below redshift z = 1.0. This distribution is inferred from the observed distribution of 2D shapes, using a reconstruction method which we test using hydrodynamic simulations. Our tests reveal a moderate bias for the inferred average disc circularity and relative thickness, but a large bias on the dispersion of these quantities. Applying the reconstruction method on COSMOS data, we find variations of the average disc circularity and relative thickness with redshift of around ∼1 per cent and ∼10 per cent, respectively, which is comparable to the error estimates on these quantities. The average relative disc thickness shows a significant mass dependence which can be accounted for by the scaling of disc radius with galaxy mass. We conclude that our data provides no evidence for a strong dependence of the average circularity and absolute thickness of disc-dominated galaxies on redshift and mass that is significant with respect to the statistical uncertainties in our analysis. These findings are expected in the absence of disruptive merging or feedback events that would affect galaxy shapes. They hence support a scenario where present-day discs form early ( z > 1.0) and subsequently undergo a tranquil evolution in isolation. However, more data and a better understanding of systematics are needed to reaffirm our results.
Spherical accretion of collisional gas in modified gravity I: self-similar solutions and a new cosmological hydrodynamical code
Authors: Zhang Han , Weinzierl Tobias , Schulz Holger , Li Baojiu
Published: July 2022

The spherical collapse scenario has great importance in cosmology since it captures several crucial aspects of structure formation. The presence of self-similar solutions in the Einstein-de Sitter (EdS) model greatly simplifies its analysis, making it a powerful tool to gain valuable insights into the real and more complicated physical processes involved in galaxy formation. While there has been a large body of research to incorporate various additional physical processes into spherical collapse, the effect of modified gravity (MG) models, which are popular alternatives to the Λ cold dark matter paradigm to explain the cosmic acceleration, is still not well understood in this scenario. In this paper, we study the spherical accretion of collisional gas in a particular MG model, which is a rare case that also admits self-similar solutions. The model displays interesting behaviours caused by the enhanced gravity and a screening mechanism. Despite the strong effects of MG, we find that its self-similar solution agrees well with that of the EdS model. These results are used to assess a new cosmological hydrodynamical code for spherical collapse simulations introduced here, which is based on the hyperbolic partial differential equation engine ExaHyPE 2. Its good agreement with the theoretical predictions confirms the reliability of this code in modelling astrophysical processes in spherical collapse. We will use this code to study the evolution of gas in more realistic MG models in future work.
Morphology, colour–magnitude, and scaling relations of galaxies in Abell 426
Authors: Khanday Sheeraz A , Saha Kanak , Iqbal Nasser , Dhiwar Suraj , Pahwa Isha
Published: July 2022

We present photometric properties of 183 member galaxies in the Abell 426 cluster using the Sloan Digital Sky Survey (SDSS) imaging and spectroscopic observation. Detailed morphology based on visual classification followed by multicomponent image decomposition of 179 galaxies is presented in the SDSS g, r, i bands. More than 80 per cent of the members are early-type galaxies (ETGs), with elliptical, dwarf elliptical (dE), and lenticular morphology and follow the red-sequence in the colour–magnitude diagram (CMD). With a few dEs and spirals in the blue cloud, the cluster CMD is nearly unimodal. The dEs are ∼2-mag fainter and follow a different Sersic index and central velocity dispersion distribution than their bright counterparts. Further, we establish the Kormendy relation (KR) and the fundamental plane relation (FPR) for five different samples of ETGs constructed based on derived physical parameters such as Sersic index, concentration, central velocity dispersion in g, r, i bands. The mean r-band slope and zero-point of the KR are 3.02 ± 0.1 and 18.65 ± 0.03 in close agreement to other cluster ellipticals in the local and higher redshift. Kinematics-based ETG sample produces the least scatter in KR with zero-point getting brighter by ∼1.3 mag from g to i band. The dEs and other low-mass ETGs follow the KR with a similar slope but with ∼1.3 mag fainter zero-point and form a parallel KR. The bright ellipticals follow an FPR with a = 1.37 ± 0.003, b = 0.35 ± 0.05, and c = −9.37 ± 0.02 in the r band; galaxies tend to deviate from this relation at the low-mass end. A catalogue with morphology and 2D structural analysis is available online.
Machine learning for galactic archaeology: a chemistry-based neural network method for identification of accreted disc stars
Authors: Tronrud Thorold , Tissera Patricia B , Gómez Facundo A , Grand Robert J J , Pakmor Ruediger , Marinacci Federico , Simpson Christine M
Published: July 2022

We develop a method (‘Galactic Archaeology Neural Network’, gann) based on neural network models (NNMs) to identify accreted stars in galactic discs by only their chemical fingerprint and age, using a suite of simulated galaxies from the Auriga Project. We train the network on the target galaxy’s own local environment defined by the stellar halo and the surviving satellites. We demonstrate that this approach allows the detection of accreted stars that are spatially mixed into the disc. Two performance measures are defined – recovery fraction of accreted stars, frecov and the probability that a star with a positive (accreted) classification is a true-positive result, P(TP). As the NNM output is akin to an assigned probability (Pa), we are able to determine positivity based on flexible threshold values that can be adjusted easily to refine the selection of presumed-accreted stars. We find that  gann identifies accreted disc stars within simulated galaxies, with high frecov and/or high P(TP). We also find that stars in Gaia–Enceladus–Sausage (GES) mass systems are over 50 per cent recovered by our NNMs in the majority (18/24) of cases. Additionally, nearly every individual source of accreted stars is detected at 10 per cent or more of its peak stellar mass in the disc. We also demonstrate that a conglomerated NNM, trained on the halo and satellite stars from all of the Auriga galaxies provides the most consistent results, and could prove to be an intriguing future approach as our observational capabilities expand.
Distinguishing between ΛCDM and f(R) gravity models using halo ellipticity correlations in simulations
Authors: Chuang Yao-Tsung , Okumura Teppei , Shirasaki Masato
Published: July 2022

There is a growing interest in utilizing intrinsic alignment (IA) of galaxy shapes as a geometric and dynamical probe of cosmology. In this paper, we present the first measurements of IA in a modified gravity model using the gravitational shear-intrinsic ellipticity correlation (GI) and intrinsic ellipticity-ellipticity correlation (II) functions of dark-matter haloes from f(R) gravity simulations. By comparing them with the same statistics measured in Lambda cold dark matter (ΛCDM) simulations, we find that the IA statistics in different gravity models show distinguishable features, with a trend similar to the case of conventional galaxy clustering statistics. Thus, the GI and II correlations are found to be useful in distinguishing between the ΛCDM and f(R) gravity models. More quantitatively, IA statistics enhance detectability of the imprint of f(R) gravity on large-scale structures by $\sim 40{{\ \rm per\ cent}}$ when combined with the conventional halo clustering in redshift space. We also find that the correlation between the axial ratio and orientation of haloes becomes stronger in f(R) gravity than that in ΛCDM. Our results demonstrate the usefulness of IA statistics as a probe of gravity beyond a consistency test of ΛCDM and general relativity.