bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substructure analysis of the RXCJ0232.2–4420 galaxy cluster
Authors: Parekh Viral , Laganá Tatiana F , Kale Ruta 
Published: March 2021

ABSTRACT
RXCJ0232.2–4420, at z = 0.28, is a peculiar system hosting a radio halo source around the cool-core of the cluster. To investigate its formation and nature, we used archival Chandra and XMM–Newton X-ray data to study the dynamical state of the cluster and detect possible substructures in the hot gas. Its X-ray surface brightness distribution shows no clear disruption except an elongation in the north-east to south-west direction. We perform the unsharp masking technique and compute morphology parameters (Gini, M20, and concentration) to characterize the degree of disturbance in the projected X-ray emission. Both of these methods revealed a substructure, which is located at ∼1 arcmin from the cluster core in the south-west direction. Previous spectral analysis conducted for RXCJ0232.2–04420 concluded that there are a short cooling time and low entropy at the cluster centre, indicating that the cluster has a cool core. Thus, we suggest that RXCJ0232.2–4420 may be a system where the core of the cluster is not showing any sign of disturbance, but the south-west substructure could be pumping energy to the detected radio halo via turbulence.
Relative depolarization of the black hole photon ring in GRMHD models of Sgr A* and M87*
Authors: Jiménez-Rosales A , Dexter J , Ressler S M , Tchekhovskoy A , Bauböck M , Dallilar Y , de Zeeuw P T , Drescher A , Eisenhauer F , von Fellenberg S , Gao F , Genzel R , Gillessen S , Habibi M , Ott T , Stadler J , Straub O , Widmann F 
Published: March 2021

ABSTRACT
Using general relativistic magnetohydrodynamic simulations of accreting black holes, we show that a suitable subtraction of the linear polarization per pixel from total intensity images can enhance the photon ring feature. We find that the photon ring is typically a factor of ≃2 less polarized than the rest of the image. This is due to a combination of plasma and general relativistic effects, as well as magnetic turbulence. When there are no other persistently depolarized image features, adding the subtracted residuals over time results in a sharp image of the photon ring. We show that the method works well for sample, viable GRMHD models of Sgr A* and M87*, where measurements of the photon ring properties would provide new measurements of black hole mass and spin, and potentially allow for tests of the ‘no-hair’ theorem of general relativity.
Reconstruction of baryon fraction in intergalactic medium through dispersion measurements of fast radio bursts
Authors: Dai Ji-Ping , Xia Jun-Qing 
Published: March 2021

ABSTRACT
Fast radio bursts (FRBs) probe the total column density of free electrons in the intergalactic medium (IGM) along the path of propagation through the dispersion measures (DMs) that depend on the baryon mass fraction in the IGM, i.e. fIGM. In this letter, we investigate the large-scale clustering information of DMs to study the evolution of fIGM. When combining with the Planck 2018 measurements, we could give tight constraints on the evolution of fIGM(z) from about 104 FRBs with the intrinsic DM scatter of $30(1+z) \rm pc\, cm^{-3}$ spanning 80 per cent of the sky and redshift range z = 0–3. First, we consider the Taylor expansion of fIGM(z) up to second order, and find that the mean relative standard deviation σ(fIGM) ≡ 〈σ[fIGM(z)]/fIGM(z)〉 is about 6.7 per cent. In order to alleviate the dependence on fiducial model, we also adopt non-parametric methods in this work, the local principle component analysis. We obtain the consistent, but weaker constraints on the evolution of fIGM(z), namely the mean relative standard deviation σ(fIGM) is 21.4 per cent. With the forthcoming surveys, this could be a complimentary method to investigate the baryon mass fraction in the IGM.
Thermodynamic evolution of a sigmoidal active region with associated flares
Authors: Mulay Sargam M , Tripathi Durgesh , Mason Helen 
Published: March 2021

ABSTRACT
Active regions often show S-shaped structures in the corona called sigmoids. These are highly sheared and twisted loops formed along the polarity inversion line. They are considered to be one of the best pre-eruption signatures for CMEs. Here, we investigate the thermodynamic evolution of an on-disc sigmoid observed during 2015 December 24–28. For this purpose, we have employed Emission Measure (EM) and filter-ratio techniques on the observations recorded by the Atmospheric Imaging Assembly (AIA) on-board the Solar Dynamics Observatory (SDO) and X-ray Telescope (XRT) on-board Hinode. The EM analysis showed multithermal plasma along the sigmoid and provided a peak temperature of ∼10–12.5 MK for all observed flares. The sigmoidal structure showed emission from Fe xviii (93.93 Å) and Fe xxi (128.75 Å) lines in the AIA 94 and 131 Å channels, respectively. Our results show that the hot plasma is often confined to very hot strands. The temperature obtained from the EM analysis was found to be in good agreement with that obtained using the XRT, AIA, and GOES filter-ratio methods. These results provide important constraints for the thermodynamic modelling of sigmoidal structures in the core of active regions. Moreover, this study also benchmarks different techniques available for temperature estimation in solar coronal structures.
A Chandra study of Abell 795 – a sloshing cluster with an FR0 radio galaxy at its centre
Authors: Ubertosi F , Gitti M , Torresi E , Brighenti F , Grandi P 
Published: March 2021

ABSTRACT
We present the first X-ray dedicated study of the galaxy cluster Abell 795 (A795) and of the Fanaroff–Riley type 0 (FR0) hosted in its brightest cluster galaxy. Using an archival 30 ks Chandra observation, we study the dynamical state and cooling properties of the intracluster medium (ICM), and we investigate whether the growth of the radio galaxy is prevented by the surrounding environment. We discover that A795 is a weakly cool-core cluster, with an observed mass deposition rate ${\lessapprox} 14$ M⊙ yr−1 in the cooling region (central ∼66 kpc). In the inner ∼30 kpc, we identify two putative X-ray cavities, and we unveil the presence of two prominent cold fronts at ∼60 and ∼178 kpc from the centre, located along a cold ICM spiral feature. The central galaxy, which is offset by 17.7 kpc from the X-ray peak, is surrounded by a multitemperature gas with an average density of ne = 2.14 × 10−2 cm−3. We find extended radio emission at 74–227 MHz centred on the cluster, exceeding the expected flux from the radio galaxy extrapolated at low frequency. We propose that sloshing is responsible for the ICM spiral morphology and the formation of the cold fronts, and that the environment alone cannot explain the compactness of the FR0. We argue that the power of the cavities and the sloshing kinetic energy can reduce and offset cooling. Considering the spectral and morphological properties of the extended radio emission, we classify it as a candidate radio mini-halo.
Measuring fundamental jet properties with multiwavelength fast timing of the black hole X-ray binary MAXI J1820+070
Authors: Tetarenko A J , Casella P , Miller-Jones J C A , Sivakoff G R , Paice J A , Vincentelli F M , Maccarone T J , Gandhi P , Dhillon V S , Marsh T R , Russell T D , Uttley P 
Published: March 2021

ABSTRACT
We present multiwavelength fast timing observations of the black hole X-ray binary MAXI J1820+070 (ASASSN-18ey), taken with the Karl G. Jansky Very Large Array (VLA), Atacama Large Millimeter/Sub-Millimeter Array (ALMA), Very Large Telescope (VLT), New Technology Telescope (NTT), Neutron Star Interior Composition Explorer (NICER), and XMM–Newton. Our data set simultaneously samples 10 different electromagnetic bands (radio – X-ray) over a 7-h period during the hard state of the 2018–2019 outburst. The emission we observe is highly variable, displaying multiple rapid flaring episodes. To characterize the variability properties in our data, we implemented a combination of cross-correlation and Fourier analyses. We find that the emission is highly correlated between different bands, measuring time-lags ranging from hundreds of milliseconds between the X-ray/optical bands to minutes between the radio/sub-mm bands. Our Fourier analysis also revealed, for the first time in a black hole X-ray binary, an evolving power spectral shape with electromagnetic frequency. Through modelling these variability properties, we find that MAXI J1820+070 launches a highly relativistic ($\Gamma =6.81^{+1.06}_{-1.15}$) and confined ($\phi =0.45^{+0.13}_{-0.11}$ deg) jet, which is carrying a significant amount of power away from the system (equivalent to $\sim 0.6 \, L_{1-100{\rm keV}}$). We additionally place constraints on the jet composition and magnetic field strength in the innermost jet base region. Overall, this work demonstrates that time-domain analysis is a powerful diagnostic tool for probing jet physics, where we can accurately measure jet properties with time-domain measurements alone.
Ultra-faint dwarf galaxies: unveiling the minimum mass of the first stars
Authors: Rossi Martina , Salvadori Stefania , Skúladóttir Ása 
Published: March 2021

ABSTRACT
The non-detection of zero-metallicity stars in ultra-faint dwarf galaxies (UFDs) can be used to constrain the initial mass function (IMF) of the first (PopIII) stars by means of a statistical comparison between available data and predictions from chemical evolution models. To this end we develop a model that follows the formation of isolated UFDs, calibrated to best reproduce the available data for the best studied system: Boötes I. Our statistical approach shows that UFDs are the best suitable systems to study the implications of the persisting non-detection of zero-metallicity stars on the PopIII IMF, i.e. its shape, the minimum mass (mmin), and the characteristic mass (mch). We show that accounting for the incomplete sampling of the IMF is essential to compute the expected number of long-lived PopIII stars in inefficiently star-forming UFDs. By simulating the colour–magnitude diagram of Boötes I, and thus take into account the mass-range of the observed stars, we can obtain even tighter constrains on mmin. By exploiting the 96 stars with measured metallicities ($\rm i \lt 19$) in the UFDs represented by our model, we demonstrate that $m_{\mathrm{ ch}} \gt 1\: \rm {M_{\odot }}$ or $m_{\mathrm{ min}} \gt 0.8 \:\rm {M_{\odot }}$ at $99\%$ confidence level. This means that a present-day IMF for PopIII stars is excluded by our model, and a top-heavy PopIII IMF is strongly favoured. We can limit $m_{\mathrm{ min}} \gt 0.8\: \rm {M_{\odot }}$ independent of the PopIII IMF shape by targeting the four UFDs Boötes I, Hercules, Leo IV, and Eridanus II with future generation instruments, such as ELT/MOSAIC ($\rm i \lt 25$), which can provide samples of &gt;10 000 stars.
Magnetic inhibition of the recollimation instability in relativistic jets
Authors: Matsumoto Jin , Komissarov Serguei S , Gourgouliatos Konstantinos N 
Published: March 2021

ABSTRACT
In this paper, we describe the results of three-dimensional relativistic magnetohydrodynamic simulations aimed at probing the role of regular magnetic field on the development of the instability that accompanies recollimation of relativistic jets. In particular, we studied the recollimation driven by the reconfinement of jets from active galactic nuclei (AGN) by the thermal pressure of galactic coronas. We find that a relatively weak azimuthal magnetic field can completely suppress the recollimation instability in such jets, with the critical magnetization parameter σcr &lt; 0.01. We argue that the recollimation instability is a variant of the centrifugal instability (CFI) and show that our results are consistent with the predictions based on the study of magnetic CFI in rotating fluids. The results are discussed in the context of AGN jets in general and the nature of the Fanaroff–Riley morphological division of extragalactic radio sources in particular.
Postcolonial Legal Pluralism
Authors: Tamanaha Brian Z. 
Published: March 2021

Abstract
This chapter examines European colonization, which created transplanted state legal systems alongside bodies of customary and religious law, and brought workers from outside in large numbers for plantations and mining, creating a wave of legal pluralism across the Global South. Colonization conventionally refers to European political, economic, and legal domination of large parts of the world from the sixteenth through the mid-twentieth centuries. European political domination involved various degrees of control over a peripheral territory as a colony, protectorate, or some other relationship; economic domination involved utilizing the land, labor, natural resources, and trade of a peripheral territory for the economic benefit of the metropole and its settler population; and legal domination involved instrumental use of law by the colonial state to enforce its political rule and achieve its exploitative economic objectives. The chapter then elaborates on postcolonial legal pluralism: how it came about, its consequences, and the situation of legal pluralism today. The topics covered include the recognition and transformation of customary law, informal village tribunals, the power of traditional leaders, conflicts over law, women’s right and human rights, and rule of law development efforts.
Understanding the Role of Populus ECERIFERUM2-Likes in the Biosynthesis of Very-Long-Chain Fatty Acids for Cuticular Waxes
Authors: Gonzales-Vigil Eliana , vonLoessl Michelle E , Chen Jeff Y , Li Sitong , Haslam Tegan M , Kunst Ljerka , Mansfield Shawn D 
Published: March 2021

Abstract
Cuticular waxes are derived from very-long-chain fatty acid (VLCFA) precursors made by the concerted action of four enzymes that form the fatty acid (FA) elongation complex. The condensing enzyme of the complex confers specificity to substrates of different chain lengths, yet on its own cannot account for the biosynthesis of VLCFAs longer than 28 carbons (C28). Recent evidence from Arabidopsis thaliana points to a synergistic role of clade II BAHD acyltransferases and condensing enzymes in the elongation of VLCFAs beyond C28. In Populus trichocarpa, clade II is composed of seven uncharacterized paralogous genes (PtCER2-like1–7). In the present study, five of these genes were heterologously expressed in yeast and their respective FA profiles were determined. PtCER2-likes differentially altered the accumulation of C28 and C30 FAs when expressed in the presence of the condensing enzyme AtCER6. Among these, PtCER2-like5 produced the highest levels of C28 FAs in yeast and its expression was localized to the epidermis in β-glucuronidase-reporter poplar lines, consistent with a role in cuticular wax biosynthesis. Complementation of the A. thaliana cer2-5 mutant with PtCER2-like5 increased the levels of C28-derived cuticular waxes at the expense of C30-derived components. Together, these results demonstrate that the role of CER2-likes in cuticular wax biosynthesis is conserved in Populus clade II BAHD acyltransferases.
Associations of Pain Numeric Rating Scale Scores Collected during Usual Care with Research Administered Patient Reported Pain Outcomes
Authors: Nugent Shannon M , Lovejoy Travis I , Shull Sarah , Dobscha Steven K , Morasco Benjamin J 
Published: March 2021

Abstract

Objective
The purpose of this study is to examine the extent to which numeric rating scale (NRS) scores collected during usual care are associated with more robust and validated measures of pain, disability, mental health, and health-related quality of life (HRQOL).

Design
We conducted a secondary analysis of data from a prospective cohort study.

Subjects
We included 186 patients with musculoskeletal pain who were prescribed long-term opioid therapy.

Setting
VA Portland Health Care System outpatient clinic.

Methods
All patients had been screened with the 0–10 NRS during routine outpatient visits. They also completed research visits that assessed pain, mental health and HRQOL every 6 months for 2 years. Accounting for nonindependence of repeated measures data, we examined associations of NRS data obtained from the medical record with scores on standardized measures of pain and its related outcomes.

Results
NRS scores obtained in clinical practice were moderately associated with pain intensity scores (B’s = 0.53–0.59) and modestly associated with pain disability scores (B’s = 0.33–0.36) obtained by researchers. Associations between pain NRS scores and validated measures of depression, anxiety, and health related HRQOL were low (B’s = 0.09–0.26, with the preponderance of B’s &lt; .20).

Conclusions
Standardized assessments of pain during usual care are moderately associated with research-administered measures of pain intensity and would be improved from the inclusion of more robust measures of pain-related function, mental health, and HRQOL.
Porous polyetheretherketone microcarriers fabricated via hydroxylation together with cell-derived mineralized extracellular matrix coatings promote cell expansion and bone regeneration
Authors: Sun Shuo , Jiao Zixue , Wang Yu , Wu Zhenxu , Wang Haowei , Ji Qingming , Liu Yi , Wang Zongliang , Zhang Peibiao 
Published: March 2021

AbstractPorous microcarriers have aroused increasing attention recently by facilitating oxygen and nutrient transfer, supporting cell attachment and growth with sufficient cell seeding density. In this study, porous polyetheretherketone (PEEK) microcarriers coated with mineralized extracellular matrix (mECM), known for their chemical, mechanical and biological superiority, were developed for orthopedic applications. Porous PEEK microcarriers were derived from smooth microcarriers using a simple wet-chemistry strategy involving the reduction of carbonyl groups. This treatment simultaneously modified surface topology and chemical composition. Furthermore, the microstructure, protein absorption, cytotoxicity and bioactivity of the obtained porous microcarriers were investigated. The deposition of mECM through repeated recellularization and decellularization on the surface of porous MCs further promoted cell proliferation and osteogenic activity. Additionally, the mECM coated porous microcarriers exhibited excellent bone regeneration in a rat calvarial defect repair model in vivo, suggesting huge potential applications in bone tissue engineering.
The Unintended Consequences of Corporate Bond ETFs: Evidence from the Taper Tantrum
Authors: Dannhauser Caitlin D , Hoseinzade Saeid 
Published: March 2021

Abstract
This paper examines whether ETFs are a unique source of corporate bond fragility. Relative to mutual funds, ETFs cater to high-liquidity-demand investors, facilitate positive feedback strategies, and transmit outflows to corporate bonds via near-proportional trading. Comparing yield spread changes of bonds from the same issuer, we show that ETFs create flow-induced pressure during the Taper Tantrum, a period of market turmoil. Redemptions used to maintain the relative price efficiency of the largest and most liquid ETFs lead to significantly higher yield spreads for 4 months before reverting. The pattern indicates ETFs amplify the effects of negative fundamental shocks.
Exosome Transplantation From Patients With Schizophrenia Causes Schizophrenia-Relevant Behaviors in Mice: An Integrative Multi-omics Data Analysis
Authors: Du Yang , Tan Wen-Long , Chen Lei , Yang Zi-Meng , Li Xue-Song , Xue Xiong , Cai Yan-Shan , Cheng Yong 
Published: March 2021

Abstract
Exosomes are involved in the pathophysiology of neuropsychiatric diseases, but the role of exosomes in schizophrenia (SCZ) is unclear. Here, we demonstrate that transplantation of serum exosomes from SCZ patients into mice caused behavioral abnormalities such as deficits in prepulse inhibition and sociability, hyperactivity, and anxiogenesis. A comparative bioinformatics analysis suggested shared and distinct differentially expressed genes (DEGs) and enriched molecular pathways in the brains of SCZ exosome-recipient mice, methylazoxymethanol acetate-treated rats, and SCZ patients, which correlates evidence of altered prefrontal–hippocampal functional coherence in SCZ. A large proportion of SCZ-relevant DEGs in the exosome-recipient mice were targets of DE exosomal miRNAs in SCZ patients. Furthermore, we identified 20 hub genes for SCZ risk genes, including BDNF and NRG1, which were DE miRNA targets in SCZ. Collectively, our study suggests that SCZ exosome transplantation caused SCZ-relevant behaviors in mice, and epigenetic regulation may contribute to the phenotypes in the SCZ exosome-recipient mice. Our results may provide a potential animal model and novel therapeutic targets for SCZ.
The Impact of University–Industry Relationships on Firms’ Performance: A Meta-Regression Analysis
Authors: Acebo Enrique , Miguel-Dávila José-Ángel , Nieto Mariano 
Published: March 2021

Abstract
The University–Industry (U–I) relationship is a fundamental part of innovation systems. A wide spread of public resources has been given to promote this relationship and a large number of studies has evaluated the results. However, while innovation theory identifies this relationship as a positive instrument to increase firms’ performance, evaluation literature reports a wide range of findings. The lack of conclusiveness results in theory and evaluation literature motivates this meta-regression analysis (MRA), built on fifty-one micro-level studies published since 1995. After controlling for publication selection bias, sample, and study heterogeneities, our results show a small effect on firms’ performance. Specifically, the size of the effect is more significant for technical outcomes than economic ones. These findings have a lot of relevance for universities, firms, and policymakers for determining open-innovation strategies and public policies.
Alternative Organizational Survival: A Comparison of Two Worker-Recuperated Businesses in Buenos Aires, Argentina
Authors: Sobering Katherine , Lapegna Pablo 
Published: March 2021

Abstract
It is widely accepted that economic indicators like efficiency, productivity, and profitability are key to explaining why some businesses survive and others do not. Yet not all work organizations ascribe to capitalist assumptions about ownership, authority, and even what constitutes success itself. Worker-recuperated businesses (WRBs) in Argentina—organizations closed by their private owners, occupied by their workers, and restarted as worker cooperatives—offer one such example. While research has documented the operational and financial challenges these businesses confront, we know little about why some survive and others do not. This article draws on qualitative and historical research in two WRBs in Buenos Aires: one that survived (Hotel Bauen) and one that closed (FORJA San Martín). Comparing the organizations’ trajectories, we argue that labor process, geographic location, and political networks are key to understanding their survival. We find that different types of labor in industrial and service workplaces in conjunction with their geographic locations impacted efforts to develop networks with political actors, consumers, and social movements that provided legitimacy and resources to enable their continuity over time. The article discusses the contributions of these findings to theories of organizations and the implications for studying alternative work organizations.