bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of gas fraction and feedback in the stability and evolution of galactic discs: implications for cosmological galaxy formation models
Authors: Fensch Jérémy , Bournaud Frédéric 
Published: May 2021

ABSTRACT
High-redshift star-forming galaxies often have irregular morphologies with giant clumps containing up to 108−109 solar masses of gas and stars. The origin and evolution of giant clumps are debated both theoretically and observationally. In most cosmological simulations, high-redshift galaxies have regular spiral structures or short-lived clumps, in contradiction with many idealized high-redshift disc models. Here, we test whether this discrepancy can be explained by the low gas fractions of galaxies in cosmological simulations. We present a series of simulations with varying gas fractions, from 25 per cent, typical of galaxies in most cosmological simulations, to 50 per cent, typical of observed galaxies at 1.5 &lt; z &lt; 3. We find that gas-poor models have short-lived clumps, that are unbound and mostly destroyed by galactic shear, even with weak stellar feedback. In contrast, gas-rich models form long-lived clumps even with boosted stellar feedback. This shows that the gas mass fraction is the primary physical parameter driving violent disc instabilities and the evolution of giant clumps on ∼108 yr time-scales, with lower impact from the calibration of the stellar feedback. Many cosmological simulations of galaxy formation have relatively gas-poor galactic discs, which could explain why giant clumps are absent or short-lived in such models. Similar baryonic and dark matter mass distribution could produce clumpy galaxies with long-lived clumps at z ∼ 2 if the gas fraction was in better agreement with observations.
Where infall meets outflows: turbulent dissipation probed by CH+ and Lyα in the starburst/AGN galaxy group SMM J02399−0136 at z ∼ 2.8
Authors: Vidal-García A , Falgarone E , Arrigoni Battaia F , Godard B , Ivison R J , Zwaan M A , Herrera C , Frayer D , Andreani P , Li Q , Gavazzi R 
Published: May 2021

ABSTRACT
We present a comparative analysis of the $\rm CH^+$(1–0) and Lyα lines, observed with the Atacama Large Millimeter Array and Keck telescope, respectively, in the field of the submillimetre-selected galaxy SMM J02399−0136 at z ∼ 2.8, which comprises a heavily obscured starburst galaxy and a broad absorption line quasar, immersed in a large Lyα nebula. This comparison highlights the critical role played by turbulence in channelling the energy across gas phases and scales, splitting the energy trail between hot/thermal and cool/turbulent phases in the circumgalactic medium (CGM). The unique chemical and spectroscopic properties of $\rm CH^+$ are used to infer the existence of a massive (∼3.5 × 1010 M⊙), highly turbulent reservoir of diffuse molecular gas of radius ∼20 kpc coinciding with the core of the Lyα nebula. The whole cool and cold CGM is shown to be inflowing towards the galaxies at a velocity ∼ 400 km s−1. Several kpc-scale shocks are detected tentatively in $\rm CH^+$ emission. Their linewidth and specific location in space and velocity with respect to the high-velocity Lyα emission suggest that they lie at the interface of the inflowing CGM and the high-velocity outflowing gas. They signpost the feeding of CGM turbulence by active galactic nuclei- and stellar-driven outflows. The mass and energy budgets of the CGM require net mass accretion at a rate commensurate with the star formation rate. From this similarity, we infer that the merger-driven burst of star formation and black-hole growth are ultimately fuelled by large-scale gas accretion.
Detecting subparsec supermassive binary black holes: Long-term monitoring perspective
Authors: Popović L Č , Simić S , Kovačević A , Ilić D 
Published: May 2021

ABSTRACT
Here we consider the perspective to detect sub-pc supermassive binary black hole (SMBBH) systems using long-term photometric and spectroscopic monitoring campaigns of active galactic nuclei. This work explores the nature of long-term spectral variability caused by the dynamical effects of SMBBH systems. We describe in great detail a model of SMBBH system which considers that both black holes have their accretion disc and additional line emitting region(s). We simulate the H β spectral band (continuum+broad H β line) for different mass ratios of components and different total masses of the SMBBH systems (106–108 M⊙). We analyse the set of continuum and broad line light curves for several full orbits of SMBBHs with different parameters, to test the possibility to extract the periodicity of the system. We consider different levels of the signal-to-noise ratio, which is added to the simulated spectra. Our analysis showed that the continuum and broad line profiles emitted from an SMBBH system are strongly dependent, not only on the mass ratio of the components but also on the total mass of the system. We found that the mean broad line profile and its rms could indicate the presence of an SMBBH. However, some effects caused by the dynamics of a binary system could be hidden due to a low signal-to-noise ratio. Finally, we can conclude that the long-term AGN monitoring campaigns could be beneficial for the detection of SMBBH candidates.
Hydrogenation of small aromatic heterocycles at low temperatures
Authors: Miksch April M , Riffelt Annalena , Oliveira Ricardo , Kästner Johannes , Molpeceres Germán 
Published: May 2021

ABSTRACT
The recent wave of detections of interstellar aromatic molecules has sparked interest in the chemical behaviour of aromatic molecules under astrophysical conditions. In most cases, these detections have been made through chemically related molecules, called proxies, that implicitly indicate the presence of a parent molecule. In this study, we present the results of the theoretical evaluation of the hydrogenation reactions of different aromatic molecules (benzene, pyridine, pyrrole, furan, thiophene, silabenzene, and phosphorine). The viability of these reactions allows us to evaluate the resilience of these molecules to the most important reducing agent in the interstellar medium, the hydrogen atom (H). All significant reactions are exothermic and most of them present activation barriers, which are, in several cases, overcome by quantum tunnelling. Instanton reaction rate constants are provided between 50 and 500 K. For the most efficiently formed radicals, a second hydrogenation step has been studied. We propose that hydrogenated derivatives of furan and pyrrole, especially 2,3-dihydropyrrole, 2,5-dihydropyrrole, 2,3-dihydrofuran, and 2,5-dihydrofuran, are promising candidates for future interstellar detections.
Detection of a 20-min time lag observed from Sgr A* between 8 and 10 GHz with the VLA
Authors: Michail Joseph M , Yusef-Zadeh Farhad , Wardle Mark 
Published: May 2021

ABSTRACT
We report the detection and analysis of a radio flare observed on 17 April 2014 from Sgr A* at 9 GHz using the VLA in its A-array configuration. This is the first reported simultaneous radio observation of Sgr A* across 16 frequency windows between 8 and 10 GHz. We cross-correlate the lowest and highest spectral windows centred at 8.0 and 9.9 GHz, respectively, and find the 8.0 GHz light-curve lagging $18.37^{+2.17}_{-2.18}$ min behind the 9.9 GHz light curve. This is the first time lag found in Sgr A*’s light curve across a narrow radio frequency bandwidth. We separate the quiescent and flaring components of Sgr A* via flux offsets at each spectral window. The emission is consistent with an adiabatically expanding synchrotron plasma, which we fit to the light curves to characterize the two components. The flaring emission has an equipartition magnetic field strength of 2.2 Gauss, size of 14 Schwarzschild radii, average speed of 12 000 km s−1, and electron energy spectrum index (N(E) ∝ E−p), p = 0.18. The peak flare flux at 10 GHz is approximately 25 per cent of the quiescent emission. This flare is abnormal as the inferred magnetic field strength and size are typically about 10 Gauss and few Schwarzschild radii. The properties of this flare are consistent with a transient warm spot in the accretion flow at a distance of 10–100 Schwarzschild radii from Sgr A*. Our analysis allows for independent characterization of the variable and quiescent components, which is significant for studying temporal variations in these components.
Momentum feedback from marginally resolved H iiregions in isolated disc galaxies
Authors: Jeffreson Sarah M R , Krumholz Mark R , Fujimoto Yusuke , Armillotta Lucia , Keller Benjamin W , Chevance Mélanie , Kruijssen J M Diederik 
Published: May 2021

ABSTRACTWe present a novel, physically motivated sub-grid model for H ii region feedback within the moving mesh code arepo, accounting for both the radiation pressure-driven and thermal expansion of the ionized gas surrounding young stellar clusters. We apply this framework to isolated disc galaxy simulations with mass resolutions between 103 and 105 M⊙ per gas cell. Each simulation accounts for the self-gravity of the gas, the momentum and thermal energy from supernovae, the injection of mass by stellar winds, and the non-equilibrium chemistry of hydrogen, carbon, and oxygen. We reduce the resolution dependence of our model by grouping those H ii regions with overlapping ionization front radii. The Strömgren radii of the grouped H ii regions are at best marginally resolved, so that the injection of purely thermal energy within these radii has no effect on the interstellar medium. By contrast, the injection of momentum increases the fraction of cold and molecular gas by more than 50 per cent at mass resolutions of 103 M⊙, and decreases its turbulent velocity dispersion by ∼10 km s−1. The mass-loading of galactic outflows is decreased by an order of magnitude. The characteristic lifetime of the least-massive molecular clouds ($M/{\rm M}_\odot \lesssim 5.6 \times 10^4$) is reduced from ∼18 to $\lesssim 10$ Myr, indicating that H ii region feedback is effective in destroying these clouds. Conversely, the lifetimes of intermediate-mass clouds ($5.6 \times 10^4 \lesssim M/{\rm M}_\odot \lesssim 5 \times 10^5$) are elongated by ∼7 Myr, likely due to a reduction in supernova clustering. The derived cloud lifetimes span the range from 10 to 40 Myr, in agreement with observations. All results are independent of whether the momentum is injected from a ‘spherical’ or a ‘blister-type’ H ii region.
Linear bias and halo occupation distribution of emission-line galaxies from Nancy Grace Roman Space Telescope
Authors: Zhai Zhongxu , Wang Yun , Benson Andrew , Chuang Chia-Hsun , Yepes Gustavo 
Published: May 2021

ABSTRACT
We present measurements of the linear galaxy bias of Hα and [O iii] emission-line galaxies (ELGs) for the High Latitude Spectroscopic Survey (HLSS) of Nancy Grace Roman Space Telescope (or Roman), using galaxy mocks constructed using semi-analytical model for galaxy formation, Galacticus, with a large cosmic volume and redshift coverage. We compute the two-point statistics of galaxies in configuration space and measure linear bias within scales of 10–50 h−1 Mpc. We adopt different selection algorithms to investigate the impact of the Roman line flux cut, as well as the effect of dust model used to calibrate Galacticus, on the bias measurements. We consider galaxies with Hα and [O iii] emissions over the redshift range 1 &lt; z &lt; 3, as specified by the current baseline for the Roman HLSS. We find that the linear bias for the Hα and [O iii] ELGs can be expressed as a linear function with respect to redshift: b ≃ 0.9z + 0.5 for H$\alpha \, (1\lt z\lt 2)$, and b ≃ z + 0.5 for [O iii] (2 &lt; z &lt; 3). We have also measured the halo occupation distributions of these Hα and [O iii] ELGs to understand their distribution within dark matter haloes. Our results provide key input to enable the reliable forecast of dark energy and cosmology constraints from Roman.
Chemical abundances in seven metal-poor H ii regions and a determination of the primordial helium abundance
Authors: Valerdi Mabel , Peimbert Antonio , Peimbert Manuel 
Published: May 2021

ABSTRACT
We conducted a long-slit spectrophotometry analysis to obtain the chemical abundances of seven metal-poor H ii regions in three galaxies: UM 160, UM 420, and TOL 0513−393. The data have been taken with the Focal Reducer Low Dispersion Spectrograph 1 (FORS1) at the 8.2-m Very Large Telescope. We derived the physical conditions and the chemical abundances of N, O, Ne, S, Ar, and Cl. We also performed a detailed analysis that involves abundance determinations using the t2 formalism. Based on He i recombination line intensity ratios, together with the {\sc HELIO 14} code, we derived the abundance of He. In addition, for a value $\Delta Y/\Delta Z_O \rm =3.3\pm 0.7$, we have estimated that the primordial helium abundance by mass is YP = 0.2448 ± 0.0033. This value agrees with values derived from Standard Big Bang Nucleosynthesis and with other recent determinations of YP.
Optimal serum ferritin level range: iron status measure and inflammatory biomarker
Authors: DePalma Ralph G , Hayes Virginia W , O'Leary Timothy J 
Published: May 2021

Abstract
This report provides perspectives concerning dual roles of serum ferritin as a measure of both iron status and inflammation. We suggest benefits of a lower range of serum ferritin as has occurred for total serum cholesterol and fasting blood glucose levels. Observations during a prospective randomized study using phlebotomy in patients with peripheral arterial disease offered unique insights into dual roles of serum ferritin both as an iron status marker and acute phase reactant. Robust positive associations between serum ferritin, interleukin 6 [IL-6], tissue necrosis factor-alpha, and high sensitivity C-reactive protein were discovered. Elevated serum ferritin and IL-6 levels associated with increased mortality and with reduced mortality at ferritin levels &lt;100 ng mL−1. Epidemiologic studies demonstrate similar outcomes. Extremely elevated ferritin and IL-6 levels also occur in individuals with high mortality due to SARS-CoV-2 infection. Disordered iron metabolism reflected by a high range of serum ferritin level signals disease severity and outcomes. Based upon experimental and epidemiologic data, we suggest testing the hypotheses that optimal ferritin levels for cardiovascular mortality reduction range from 20 to 100 ng mL−1 with % transferrin levels from 20 to 50%, to ensure adequate iron status and that ferritin levels above 194 ng mL−1 associate with all-cause mortality in population cohorts.
RNA sequence analysis reveals ITGAL/CD11A as a stromal regulator of murine low-grade glioma growth
Authors: De Andrade Costa Amanda , Chatterjee Jit , Cobb Olivia , Sanapala Shilpa , Scheaffer Suzanne , Guo Xiaofan , Dahiya Sonika , Gutmann David H 
Published: May 2021

Abstract

Background
Emerging insights from numerous laboratories have revealed important roles for nonneoplastic cells in the development and progression of brain tumors. One of these nonneoplastic cellular constituents, glioma-associated microglia (GAM), represents a unique population of brain monocytes within the tumor microenvironment that have been reported to both promote and inhibit glioma proliferation. To elucidate the role of GAM in the setting of low-grade glioma (LGG), we leveraged RNA sequencing meta-analysis, genetically engineered mouse strains, and human biospecimens.

Methods
Publicly available disease-associated microglia (DAM) RNA-seq datasets were used, followed by immunohistochemistry and RNAScope validation. CD11a-deficient mouse microglia were used for in vitro functional studies, while LGG growth in mice was assessed using anti-CD11a neutralizing antibody treatment of Neurofibromatosis type 1 (Nf1) optic glioma mice in vivo.

Results
We identified Itgal/CD11a enrichment in GAM relative to other DAM populations, which was confirmed in several independently generated murine models of Nf1 optic glioma. Moreover, ITGAL/CD11A expression was similarly increased in human LGG (pilocytic astrocytoma) specimens from several different datasets, specifically in microglia from these tumors. Using CD11a-knockout mice, CD11a expression was shown to be critical for murine microglia CX3CL1 receptor (Cx3cr1) expression and CX3CL1-directed motility, as well as glioma mitogen (Ccl5) production. Consistent with an instructive role for CD11a+ microglia in stromal control of LGG growth, antibody-mediated CD11a inhibition reduced mouse Nf1 LGG growth in vivo.

Conclusions
Collectively, these findings establish ITGAL/CD11A as a critical microglia regulator of LGG biology relevant to future stroma-targeted brain tumor treatment strategies.
For or Against Tobacco Control: Sponsored Tobacco Advocacy Messages on Facebook and Instagram
Authors: Majmundar Anuja , Moran Meghan Bridgid 
Published: May 2021

AbstractIntroductionThis study explores sponsored tobacco advocacy messages on Facebook and Instagram by: (1) Examining differences in message performance metrics, funding sources, and audience characteristics of anti- and protobacco messages in the United States, and (2) Characterizing audience exposure to anti- and protobacco message themes across different age-groups and by gender.MethodsThe analysis sample consisting of 375 tobacco-advocacy related messages on Instagram and/or Facebook in the United States from May 29, 2020 to July 26, 2020 was obtained from the Facebook Ad Library Application Programming Interface. Chi-square tests compared differences in anti- and protobacco messages by potential reach, impressions, approximate spend ($), social media platform type, average duration of delivery, type of funding sources, and audience age and gender exposure. Percentage distribution of message themes and audience exposure by age and gender were also examined.ResultsAntitobacco messages (n = 334, 89.07%) exceeded protobacco messages (n = 41, 10.93%) overall. Antitobacco messages had lower potential reach, received a lower proportion of impressions, and spent a lower proportion of money per message. Protobacco advocacy was funded primarily by the tobacco industry and advocacy groups. A small fraction of antitobacco advocacy messages reached young adults and men. Among protobacco advocacy messages, a majority of messages highlighting tobacco regulations, addiction, citizen advocacy, flavors, and impact on economy reached mostly men.ConclusionResults illustrate important gaps in current sponsored antitobacco advocacy efforts, demonstrate the feasibility of monitoring sponsored tobacco advocacy on these platforms, and offer insights for future antitobacco advocacy campaigns.ImplicationsFuture antitobacco advocacy efforts on social media may consider more focused efforts in reaching young adults and men and in leveraging strategic social media analytics to improve their overall potential reach and impressions.
How plants protect themselves from ultraviolet-B radiation stress
Authors: Shi Chen , Liu Hongtao 
Published: May 2021

Abstract
Ultraviolet-B (UV-B) radiation has a wavelength range of 280–315 nm. Plants perceive UV-B as an environmental signal and a potential abiotic stress factor that affects development and acclimation. UV-B regulates photomorphogenesis including hypocotyl elongation inhibition, cotyledon expansion, and flavonoid accumulation, but high intensity UV-B can also harm plants by damaging DNA, triggering accumulation of reactive oxygen species, and impairing photosynthesis. Plants have evolved “sunscreen” flavonoids that accumulate under UV-B stress to prevent or limit damage. The UV-B receptor UV RESISTANCE LOCUS 8 (UVR8) plays a critical role in promoting flavonoid biosynthesis to enhance UV-B stress tolerance. Recent studies have clarified several UVR8-mediated and UVR8-independent pathways that regulate UV-B stress tolerance. Here, we review these additions to our understanding of the molecular pathways involved in UV-B stress tolerance, highlighting the important roles of ELONGATED HYPOCOTYL 5, BRI1-EMS-SUPPRESSOR1, MYB DOMAIN PROTEIN 13, MAP KINASE PHOSPHATASE 1, and ATM- and RAD3-RELATED. We also summarize the known interactions with visible light receptors and the contribution of melatonin to UV-B stress responses. Finally, we update a working model of the UV-B stress tolerance pathway.
Incorporating an unincorporated charity
Authors: Mills Matthew 
Published: May 2021

Abstract
Every year, a substantial number of trustees ‘convert’ their unincorporated charities to incorporated charities. However, there is surprisingly little guidance in charity law books on the powers that trustees have to make and give effect to the decision to incorporate. This article seeks to redress the balance. It will explain what incorporating a charity involves and why it is so popular. It will then set out the powers which charity trustees might have to incorporate an unincorporated charity and the methods for transferring the unincorporated charity’s assets.
Nonischemic cardiomyopathy with reduced ejection fraction secondary to hyperthyroidism
Authors: Martin Melanie M. , Collins Megan R. 
Published: May 2021

ABSTRACT
Dilated cardiomyopathy is a form of heart failure characterized by left ventricular dilation with impaired systolic function. Causes may include ischemic heart disease, hypertensive heart disease, valvular heart disease, endocrine disorders, substance use, and viral diseases. This case report describes a patient with new-onset heart failure, initially diagnosed as idiopathic dilated cardiomyopathy with pericarditis secondary to a virus but later found to be secondary to hyperthyroidism.
Narcolepsy
Authors: Anderson Diana 
Published: May 2021

ABSTRACT
Narcolepsy continues to be a significantly underdiagnosed/misdiagnosed condition worldwide. According to the National Institutes of Health (NIH), an estimated 135,000 to 200,000 patients in the United States are living with narcolepsy. However, due to the number of patients who either do not seek medical advice for their symptoms or receive an incorrect initial diagnosis at onset, this number may be higher. This article reviews the different subtypes of narcolepsy along with the pathophysiology, screening guidelines, clinical features, diagnosis, and management of the disorder. Educational awareness from a healthcare and patient standpoint can enhance early detection and accurate diagnosis of narcolepsy and improve patient quality of life.
PA job satisfaction and career plans
Authors: Halasy Michael P. , West Colin P. , Shanafelt Tait , O'Laughlin Danielle J. , Satele Daniel , Dyrbye Liselotte N. 
Published: May 2021

ABSTRACT

Objective:
To understand the relationships between burnout, job satisfaction, and career plans among physician assistants in the United States.

Methods:
The authors surveyed PAs in 2016. The survey included the Maslach Burnout Inventory and items on job satisfaction and career plans.

Results:
Overall 82.7% of PAs were satisfied with their job, 32.2% indicated intent to leave their current position, and 19.5% reported intent to reduce work hours. On multivariate analysis, burnout increased the odds of job dissatisfaction, intent to reduce work hours within the next year, and intent to leave the current practice in the next 2 years.

Conclusions:
About a third of PAs indicated intent to leave their current practice and one in five indicated intent to reduce their clinical hours. Burnout was an independent predictor of job satisfaction and career plans.