bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hyper-Eddington black hole growth in star-forming molecular clouds and galactic nuclei: can it happen?
Authors: Shi Yanlong , Kremer Kyle , Grudić Michael Y , Gerling-Dunsmore Hannalore J , Hopkins Philip F 
Published: November 2022

ABSTRACT
Formation of supermassive black holes (BHs) remains a theoretical challenge. In many models, especially beginning from stellar relic ‘seeds,’ this requires sustained super-Eddington accretion. While studies have shown BHs can violate the Eddington limit on accretion disc scales given sufficient ‘fuelling’ from larger scales, what remains unclear is whether or not BHs can actually capture sufficient gas from their surrounding interstellar medium (ISM). We explore this in a suite of multiphysics high-resolution simulations of BH growth in magnetized, star-forming dense gas complexes including dynamical stellar feedback from radiation, stellar mass-loss, and supernovae, exploring populations of seeds with masses $\sim 1\!-\!10^{4}\, \mathrm{M}_{\odot }$. In this initial study, we neglect feedback from the BHs: so this sets a strong upper limit to the accretion rates seeds can sustain. We show that stellar feedback plays a key role. Complexes with gravitational pressure/surface density below $\sim 10^{3}\, \mathrm{M}_{\odot }\, {\rm pc^{-2}}$ are disrupted with low star formation efficiencies so provide poor environments for BH growth. But in denser cloud complexes, early stellar feedback does not rapidly destroy the clouds but does generate strong shocks and dense clumps, allowing $\sim 1{{\ \rm per\ cent}}$ of randomly initialized seeds to encounter a dense clump with low relative velocity and produce runaway, hyper-Eddington accretion (growing by orders of magnitude). Remarkably, mass growth under these conditions is almost independent of initial BH mass, allowing rapid intermediate-mass black hole (IMBH) formation even for stellar-mass seeds. This defines a necessary (but perhaps not sufficient) set of criteria for runaway BH growth: we provide analytic estimates for the probability of runaway growth under different ISM conditions.
3D simulations of strongly magnetized non-rotating supernovae: explosion dynamics and remnant properties
Authors: Varma Vishnu , Müller Bernhard , Schneider Fabian R N 
Published: November 2022

ABSTRACT
We investigate the impact of strong initial magnetic fields in core-collapse supernovae of non-rotating progenitors by simulating the collapse and explosion of a $16.9\, \mathrm{M}_\odot$ star for a strong- and weak-field case assuming a twisted-torus field with initial central field strengths of ${\approx }10^{12}$ and ${\approx }10^{6}\, \mathrm{G}$. The strong-field model has been set up with a view to the fossil-field scenario for magnetar formation and emulates a pre-collapse field configuration that may occur in massive stars formed by a merger. This model undergoes shock revival already $100\, \mathrm{ms}$ after bounce and reaches an explosion energy of $9.3\times 10^{50}\, \mathrm{erg}$ at $310\, \mathrm{ms}$, in contrast to a more delayed and less energetic explosion in the weak-field model. The strong magnetic fields help trigger a neutrino-driven explosion early on, which results in a rapid rise and saturation of the explosion energy. Dynamically, the strong initial field leads to a fast build-up of magnetic fields in the gain region to 40 per cent of kinetic equipartition and also creates sizable pre-shock ram pressure perturbations that are known to be conducive to asymmetric shock expansion. For the strong-field model, we find an extrapolated neutron star kick of ${\approx }350\, \mathrm{km}\, \mathrm{s}^{-1}$, a spin period of ${\approx }70\, \mathrm{ms}$, and no spin-kick alignment. The dipole field strength of the proto-neutron star is $2\times 10^{14}\, \mathrm{G}$ by the end of the simulation with a declining trend. Surprisingly, the surface dipole field in the weak-field model is stronger, which argues against a straightforward connection between pre-collapse fields and the birth magnetic fields of neutron stars.
Non-thermal emission from mildly relativistic dynamical ejecta of neutron star mergers
Authors: Sadeh Gilad , Guttman Or , Waxman Eli 
Published: November 2022

ABSTRACT
Binary neutron star mergers are expected to produce fast dynamical ejecta, with mildly relativistic velocities extending to β = v/c &gt; 0.6. We consider the radio to X-ray synchrotron emission produced by collisionless shocks driven by such fast ejecta into the interstellar medium. Analytical expressions are given for spherical ejecta with broken power-law mass (or energy) distributions, M(&gt; γβ) ∝ (γβ)−s with s = sKN at γβ &lt; γ0β0 and s = sft at γβ &gt; γ0β0 (where γ is the Lorentz factor). For parameter values characteristic of merger calculation results – a ‘shallow’ mass distribution, 1 &lt; sKN &lt; 3, for the bulk of the ejecta (at γβ ≈ 0.2), and a steep, sft &gt; 5, ‘fast tail’ mass distribution – our model provides an accurate (to tens of per cent) description of the evolution of the flux, including at the phase of deceleration to subrelativistic expansion. This is a significant improvement over earlier results, based on extrapolations of results valid for γβ ≫ 1 or ≪1 to γβ ≈ 1, which overestimate the flux by an order of magnitude for typical parameter values. It will enable a more reliable inference of ejecta parameters from future measurements of the non-thermal emission. For the merger event GW170817, the existence of a ‘fast tail’ is expected to produce detectable radio and X-ray fluxes over a time-scale of ∼104 d.
Covariance matrices for variance-suppressed simulations
Authors: Zhang Tony , Chuang Chia-Hsun , Wechsler Risa H , Alam Shadab , DeRose Joseph , Feng Yu , Kitaura Francisco-Shu , Pellejero-Ibanez Marcos , Rodríguez-Torres Sergio , To Chun-Hao , Yepes Gustavo , Zhao Cheng 
Published: November 2022

ABSTRACT
Cosmological N-body simulations provide numerical predictions of the structure of the Universe against which to compare data from ongoing and future surveys, but the growing volume of the Universe mapped by surveys requires correspondingly lower statistical uncertainties in simulations, usually achieved by increasing simulation sizes at the expense of computational power. It was recently proposed to reduce simulation variance without incurring additional computational costs by adopting fixed-amplitude initial conditions. This method has been demonstrated not to introduce bias in various statistics, including the two-point statistics of galaxy samples typically used for extracting cosmological parameters from galaxy redshift survey data, but requires us to revisit current methods for estimating covariance matrices of clustering statistics for simulations. In this work, we find that it is not trivial to construct covariance matrices analytically for fixed-amplitude simulations, but we demonstrate that ezmock (Effective Zel’dovich approximation mock catalogue), the most efficient method for constructing mock catalogues with accurate two- and three-point statistics, provides reasonable covariance matrix estimates for such simulations. We further examine how the variance suppression obtained by amplitude-fixing depends on three-point clustering, small-scale clustering, and galaxy bias, and propose intuitive explanations for the effects we observe based on the ezmock bias model.
Models for metal-poor stars with different initial abundances of C, N, O, Mg, and Si − III. Grids of isochrones for −2.5 ≤ [Fe/H] ≤ −0.5 and helium abundances Y = 0.25 and 0.29 at each metallicity
Authors: VandenBerg Don A 
Published: November 2022

ABSTRACT
Stellar evolutionary tracks for $0.12 \le {\cal M}/{\cal M_{\odot }}\le 1.0$ have been computed for each of several variations in the abundances of C, N, and O, assuming mass-fraction helium abundances Y = 0.25 and 0.29, and 11 metallicities in the range −2.5 ≤ [Fe/H] ≤ −0.5, in 0.2-dex increments. Such computations are provided for mixtures with [O/Fe] between +0.4 and +0.8, for different C:N:O ratios at a fixed value of [CNO/Fe] and for enhanced C. Computer codes are provided to interpolate within these grids to produce isochrones for ages ${\gtrsim}7$ Gyr and to generate magnitudes and colours for many broad-band filters using bolometric corrections based on MARCS model atmospheres and synthetic spectra. The models are compared with (i) similar computations produced by other workers, (ii) observed UV, optical, and IR colour-magnitude diagrams (CMDs), (iii) the effective temperatures, (V − IC)0 and (V − KS)0 colours of Pop. II stars in the solar neighbourhood, and (iv) empirical data for the absolute magnitude of the tip of the red-giant branch (TRGB). The isochrones are especially successful in reproducing the observed morphologies of optical CMDs and in satisfying the TRGB constraints. They also fare quite well in explaining the IR colours of low-mass stars in globular clusters, indicating that they have [O/Fe] ≈ +0.6, though some challenges remain.
The STRING database in 2023: protein–protein association networks and functional enrichment analyses for any sequenced genome of interest
Authors: Szklarczyk Damian , Kirsch Rebecca , Koutrouli Mikaela , Nastou Katerina , Mehryary Farrokh , Hachilif Radja , Gable Annika L , Fang Tao , Doncheva Nadezhda T , Pyysalo Sampo , Bork Peer , Jensen Lars J , von Mering Christian 
Published: November 2022

AbstractMuch of the complexity within cells arises from functional and regulatory interactions among proteins. The core of these interactions is increasingly known, but novel interactions continue to be discovered, and the information remains scattered across different database resources, experimental modalities and levels of mechanistic detail. The STRING database (https://string-db.org/) systematically collects and integrates protein–protein interactions—both physical interactions as well as functional associations. The data originate from a number of sources: automated text mining of the scientific literature, computational interaction predictions from co-expression, conserved genomic context, databases of interaction experiments and known complexes/pathways from curated sources. All of these interactions are critically assessed, scored, and subsequently automatically transferred to less well-studied organisms using hierarchical orthology information. The data can be accessed via the website, but also programmatically and via bulk downloads. The most recent developments in STRING (version 12.0) are: (i) it is now possible to create, browse and analyze a full interaction network for any novel genome of interest, by submitting its complement of encoded proteins, (ii) the co-expression channel now uses variational auto-encoders to predict interactions, and it covers two new sources, single-cell RNA-seq and experimental proteomics data and (iii) the confidence in each experimentally derived interaction is now estimated based on the detection method used, and communicated to the user in the web-interface. Furthermore, STRING continues to enhance its facilities for functional enrichment analysis, which are now fully available also for user-submitted genomes.
Structure of Escherichia coli heat shock protein Hsp15 in complex with the ribosomal 50S subunit bearing peptidyl-tRNA
Authors: Safdari Haaris A , Kasvandik Sergo , Polte Christine , Ignatova Zoya , Tenson Tanel , Wilson Daniel N 
Published: November 2022

Abstract
In Escherichia coli, the heat shock protein 15 (Hsp15) is part of the cellular response to elevated temperature. Hsp15 interacts with peptidyl-tRNA-50S complexes that arise upon dissociation of translating 70S ribosomes, and is proposed to facilitate their rescue and recycling. A previous structure of E. coli Hsp15 in complex with peptidyl-tRNA-50S complex reported a binding site located at the central protuberance of the 50S subunit. By contrast, recent structures of RqcP, the Hsp15 homolog in Bacillus subtilis, in complex with peptidyl-tRNA-50S complexes have revealed a distinct site positioned between the anticodon-stem-loop (ASL) of the P-site tRNA and H69 of the 23S rRNA. Here we demonstrate that exposure of E. coli cells to heat shock leads to a decrease in 70S ribosomes and accumulation of 50S subunits, thus identifying a natural substrate for Hsp15 binding. Additionally, we have determined a cryo-EM reconstruction of the Hsp15-50S-peptidyl-tRNA complex isolated from heat shocked E. coli cells, revealing that Hsp15 binds to the 50S-peptidyl-tRNA complex analogously to its B. subtilis homolog RqcP. Collectively, our findings support a model where Hsp15 stabilizes the peptidyl-tRNA in the P-site and thereby promotes access to the A-site for putative rescue factors to release the aberrant nascent polypeptide chain.
Growth dynamics of incidental meningiomas: A prospective long-term follow-up study
Authors: Strømsnes Torbjørn Austveg , Lund-Johansen Morten , Skeie Geir Olve , Eide Geir Egil , Behbahani Maziar , Skeie Bente Sandvei 
Published: November 2022

AbstractBackgroundThere is no consensus on the management of incidental meningiomas. The literature on long-term growth dynamics is sparse and the natural history of these tumors remains to be illuminated.MethodsWe prospectively assessed long-term tumor growth dynamics and survival rates during active monitoring of 62 patients (45 female, mean age 63.9 years) harboring 68 tumors. Clinical and radiological data were obtained every 6 months for 2 years, annually until 5 years, then every second year.ResultsThe natural progression of incidental meningiomas during 12 years of monitoring was growth (P &lt; .001). However, mean growth decelerated at 1.5 years and became insignificant after 8 years. Self-limiting growth patterns were seen in 43 (63.2%) tumors, non-decelerating in 20 (29.4%) and 5 (7.4%) were inconclusive due to  ≤ 2 measurements. Decelerating growth persisted once established. Within 5 years, 38 (97.4%) of 39 interventions were initiated. None developed symptoms prior to intervention. Large tumors (P &lt; .001) involving venous sinuses (P = .039) grew most aggressively. Since inclusion 19 (30.6%) patients have died of unrelated causes and 2 (3%) from grade 2 meningiomas.ConclusionActive monitoring seems a safe and appropriate first-line management of incidental meningiomas. Intervention was avoided in  &gt; 40% with indolent tumors in this cohort. Treatment was not compromised by tumor growth. Clinical follow-up seems sufficient beyond 5 years if self-limiting growth is established. Steady or accelerating growth warrant monitoring until they reach a stable state or intervention is initiated.
The microvariability and wavelength dependence of polarization degree/angle of BL Lacertae in the outburst 2020 to 2021
Authors: Imazawa Ryo , Sasada Mahito , Hazama Natsuko , Fukazawa Yasushi , Kawabata Koji S , Nakaoka Tatsuya , Akitaya Hiroshi , Bohn Thomas , Gangopadhyay Anjasha 
Published: November 2022

Abstract
We have obtained simultaneous and continuous photo-polarization observations of the blazar BL Lacertae in optical and near-infrared (NIR) bands during an historical outburst from 2020 to 2021. In total, 14 nights of observations were performed where 10 observations show microvariability on timescales of a few minutes to several hours. This suggests a compact emission region, and the timescales are difficult to explain by a one-zone shock-in-jet model. Moreover, we found significant differences in the polarization degree (PD) and angle between optical and NIR bands. Nine nights showed a PD in the optical band that is greater than or equal to that in the NIR band, which can be explained by either a shock-in-jet model or the Turbulent Extreme Multi-Zone (TEMZ) model. On the other hand, five nights showed higher PD in an NIR band than an optical band, which cannot be explained by simple shock-in-jet models nor the simple TEMZ model. The observed timescales and wavelength-dependency of the PD and polarization angle suggest the existence of complicated multiple emission regions such as an irregular TEMZ model.
X-ray spectroscopy of the accretion disk corona source 2S 0921−630 with Suzaku archival data
Authors: Yoneyama Tomokage , Dotani Tadayasu 
Published: November 2022

Abstract
2S 0921−630 is an eclipsing low-mass X-ray binary (LMXB) with an orbital period of ∼9 d. Past X-ray observations have revealed that 2S 0921−630 has an extended accretion disk corona (ADC), from which most of the X-rays from the system are emitted. We report the result of our Suzaku archival data analysis of 2S 0921−630. The average X-ray spectrum is reproduced with a blackbody emission (kTbb ∼ 0.3 keV) Comptonized by optically thick gas (“Compton cloud”; optical depth τ ∼ 21) with a temperature of ∼2 keV, combined with 13 emission lines. We find that most of the emission lines correspond to highly ionized atoms: O, Ne, Mg, Si, S, Ar, and Fe. A Kα emission line and an absorption edge of semi-neutral iron (Fe  textsci– textscxvii) are also detected. The semi-neutral iron Kα line is significantly broad, with a width of 0.11 ± 0.02 keV in sigma, which corresponds to the Doppler broadening by the Kepler motion at a radius of ∼109 cm. We suggest that the observed semi-neutral iron line originates at the inner part of the accretion disk in the immediate outside of the Compton cloud, i.e., the Compton cloud may have a radius of ∼109 cm.
Medical cannabis in schools: A qualitative study on the experiences of clinicians
Authors: Mansell Holly , Zaslawski Zina , Kelly Lauren E , Lougheed Taylor , Brace Tracy , Alcorn Jane 
Published: November 2022

Abstract

Objectives
Guidance is lacking for medical cannabis use in Canadian schools in both legislation and approach; the impact of ambiguous policy on patient care is unknown. A qualitative study was undertaken to explore the experiences of clinicians who care for school-aged children who take medical cannabis.

Methods
Semi-structured interviews were recorded and transcribed verbatim. Qualitative content analysis performed using the Dedoose qualitative software ascribed meaning units and codes, which were further consolidated into categories and subcategories.

Results
Thirteen physicians were interviewed virtually, representing seven provinces in Canada. The physicians provided care for between five and hundreds of school-aged children who took medical cannabis. The most common indications were refractory seizure disorders and autism. The interviews provided rich descriptions on perceptions of medical cannabis in schools, and in general. Five overarching categories were identified across both domains including variability, challenges (subcategories: lack of knowledge, stigma, lack of policy, and pragmatic challenges), potential solutions (subcategories: treat it like other medications, communication, education, and family support), positive experiences and improvements over time.

Conclusion
In Canada, cannabis-based medicine use in schools still faces important challenges. Effective education, communication, family support and policy refinements that allow cannabis to be treated like other prescription medications are recommended to improve the status quo. These findings will guide the C4T Medical Cannabis in Schools Working Group’s future priorities and initiatives.
Breeding crops for drought-affected environments and improved climate resilience
Authors: Cooper Mark , Messina Carlos D 
Published: November 2022

AbstractBreeding climate-resilient crops with improved levels of abiotic and biotic stress resistance as a response to climate change presents both opportunities and challenges. Applying the framework of the “breeder’s equation,” which is used to predict the response to selection for a breeding program cycle, we review methodologies and strategies that have been used to successfully breed crops with improved levels of drought resistance, where the target population of environments (TPEs) is a spatially and temporally heterogeneous mixture of drought-affected and favorable (water-sufficient) environments. Long-term improvement of temperate maize for the US corn belt is used as a case study and compared with progress for other crops and geographies. Integration of trait information across scales, from genomes to ecosystems, is needed to accurately predict yield outcomes for genotypes within the current and future TPEs. This will require transdisciplinary teams to explore, identify, and exploit novel opportunities to accelerate breeding program outcomes; both improved germplasm resources and improved products (cultivars, hybrids, clones, and populations) that outperform and replace the products in use by farmers, in combination with modified agronomic management strategies suited to their local environments.
Scaffold-based tissue engineering strategies for soft–hard interface regeneration
Authors: Li Yibo , Zhou Mo , Zheng Wenzhuo , Yang Jianying , Jiang Nan 
Published: November 2022

AbstractRepairing injured tendon or ligament attachments to bones (enthesis) remains costly and challenging. Despite superb surgical management, the disorganized enthesis newly formed after surgery accounts for high recurrence rates after operations. Tissue engineering offers efficient alternatives to promote healing and regeneration of the specialized enthesis tissue. Load-transmitting functions thus can be restored with appropriate biomaterials and engineering strategies. Interestingly, recent studies have focused more on microstructure especially the arrangement of fibers since Rossetti successfully demonstrated the variability of fiber underspecific external force. In this review, we provide an important update on the current strategies for scaffold-based tissue engineering of enthesis when natural structure and properties are equally emphasized. We firstly described compositions, structures and features of natural enthesis with their special mechanical properties highlighted. Stimuli for growth, development and healing of enthesis widely used in popular strategies are systematically summarized. We discuss the fabrication of engineering scaffolds from the aspects of biomaterials, techniques and design strategies and comprehensively evaluate the advantages and disadvantages of each strategy. At last, this review pinpoints the remaining challenges and research directions to make breakthroughs in further studies.
Numeric work: The efforts of calculation actors to make numbers count in climate and energy policy
Authors: Jørgensen Susanne , Sørensen Knut H 
Published: November 2022

AbstractPolicy documents suggest that quantitative information is important in the development of climate and energy policy. This is supported by quantitative studies research into the use of numbers in governance, which tends to assume that numbers have sufficient epistemic authority to be used by policymakers because they are believed to be trustworthy since they are produced through mechanical objectivity. This paper questions such assumptions, by analysing the extent of extra-calculative work when providing numeric information to policymakers. We term such efforts numeric work and analyse the extent and content of such work based on interviewed experts who are engaged with calculating climate and energy issues in the context of policymaking in Norway. Numeric work shares features with the actor–network theory concept of translation but differs due to the dialogic interaction between calculation actors and policymakers that includes efforts to improve the transparency of calculation, which counters a complete black-boxing of calculation results.