bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kangaroos at maximum capacity: health assessment of free-ranging eastern grey kangaroos on a coastal headland
Authors: Brandimarti Maquel E , Gray Rachael , Silva Fabiola R O , Herbert Catherine A 
Published: February 2021

Abstract
Sprawling urban development is fragmenting the landscape and native wildlife habitats on the Australian east coast. The impact of this rapid urbanization on wildlife health is largely unknown. This study surveyed the health of a high-density (5.4 individuals per ha) population of eastern grey kangaroos (Macropus giganteus) affected by urban encroachment and prolonged drought. Blood parameters (hematological and serum protein), trace element and heavy metal concentrations, and parasite counts (fecal worm egg counts, ticks, and mites) are reported for a sample of ≤ 54 kangaroos at Look at Me Now Headland, New South Wales, Australia. These parameters were compared to lower density kangaroo populations from other sites in New South Wales. We found the health and welfare of this population to be severely compromised, with nonregenerative anemia and nutritional deficiencies evident. Our results indicate that high-density kangaroo populations isolated by urban encroachment are at significant health risk. To prevent further decline in this population’s health, we discuss management strategies that could be employed, concurrent with ongoing health and disease monitoring, to mitigate the poor health outcomes in this population. We conclude that it is essential to retain habitat connectivity when altering land use in areas with resident kangaroo populations if managers are to maintain healthy populations.
Fasudil alleviated insulin resistance through promotion of proliferation, attenuation of cell apoptosis and inflammation and regulation of RhoA/Rho kinase/insulin/nuclear factor-κB signalling pathway in HTR-8/SVneo cells
Authors: Bai Yu , Du Qiang , Zhang Le , Li Ling , Tang Lei , Zhang Wei , Du Runyu , Li Ping , Li Ling 
Published: February 2021

Abstract

Objectives
The aim of this study was to evaluate the effects of fasudil on insulin resistance (IR) in HTR-8/SVneo cells.

Methods
HTR-8/SVneo cells were treated with insulin or/and fasudil. Cell proliferation, apoptosis, inflammation and related signalling pathways were assessed.

Key findings
Insulin treatment significantly enhanced the protein expressions of RhoA and Rho kinase (ROCK1 and ROCK2), but decreased glucose consumption. Administration of fasudil effectively promoted glucose uptake. Moreover, fasudil enhanced cell viability and the level of proliferating cell nuclear antigen (PCNA). Insulin-mediated cell apoptosis was inhibited by fasudil via the down-regulation of bax and cleaved-caspase-3, and the up-regulation of bcl-2. At the same time, fasudil led to the reduction of IL-1β, TNF-α, IL-6 and IL-8 mRNA levels in insulin-treated cells. In addition, RhoA, ROCK2 and phosphorylated myosin phosphatase target subunit-1 (p-MYPT-1) expressions were down-regulated by fasudil. Importantly, fasudil activated insulin receptor substrate-1 (IRS-1) through increasing p-IRS-1 (Tyr612) and p-Akt expressions. The nuclear NF-κB p65 and p-IκB-α levels were reduced via the administration of fasudil in insulin-treated cells.

Conclusions
Fasudil mitigated IR by the promotion of cell proliferation, inhibition of apoptosis and inflammation and regulation of RhoA/ROCK/insulin/NF-κB signalling pathway through in vitro studies.
The trafficking machinery of lytic and protein storage vacuoles: how much is shared and how much is distinct?
Authors: Zhang Xiuxiu , Li Hui , Lu Hai , Hwang Inhwan 
Published: February 2021

Abstract
Plant cells contain two types of vacuoles, the lytic vacuole (LV) and protein storage vacuole (PSV). LVs are present in vegetative cells, whereas PSVs are found in seed cells. The physiological functions of the two types of vacuole differ. Newly synthesized proteins must be transported to these vacuoles via protein trafficking through the endomembrane system for them to function. Recently, significant advances have been made in elucidating the molecular mechanisms of protein trafficking to these organelles. Despite these advances, the relationship between the trafficking mechanisms to the LV and PSV remains unclear. Some aspects of the trafficking mechanisms are common to both types of vacuole, but certain aspects are specific to trafficking to either the LV or PSV. In this review, we summarize recent findings on the components involved in protein trafficking to both the LV and PSV and compare them to examine the extent of overlap in the trafficking mechanisms. In addition, we discuss the interconnection between the LV and PSV provided by the protein trafficking machinery and the implications for the identity of these organelles.
Broad-band study of OQ 334 during its flaring state
Authors: Prince Raj , Khatoon Rukaiya , Stalin C S 
Published: February 2021

ABSTRACT
The blazar OQ 334 displayed a γ-ray flare in 2018, after being in the long quiescent γ-ray state since 2008. Subsequent to the flare, the source was in a higher γ-ray flux state and again flared in 2020. We present here the first spectral and timing analysis of the source at its various flaring states. During the higher γ-ray state, we found four major peaks identified as P1, P2, P3, and P4. From timing analysis we found rise and decay time of the order of hours with the fastest variability time of 9.01 ± 0.78 h. We found the highest γ-ray photon of 77 GeV during P4, which suggests the location of the γ-ray emitting region at the outer edge of the broad line region or the inner edge of the torus. The γ-ray spectral analysis of the source indicates that during P4, the γ-ray spectrum clearly deviates from the power-law behaviour. From cross-correlation analysis of the γ-ray and radio light curves, we found that the two emission regions are separated by about 11 pc. Our broad-band spectral energy distribution modelling of the source during quiescent and active phases indicates that more electron and proton power are required to change the source from low flux to high flux state. The Anderson–Darling test and histogram fitting results suggest that the three days binned γ-ray fluxes follow a lognormal distribution.
The relativistic binary programme on MeerKAT: science objectives and first results
Authors: Kramer M , Stairs I H , Venkatraman Krishnan V , Freire P C C , Abbate F , Bailes M , Burgay M , Buchner S , Champion D J , Cognard I , Gautam T , Geyer M , Guillemot L , Hu H , Janssen G , Lower M E , Parthasarathy A , Possenti A , Ransom S , Reardon D J , Ridolfi A , Serylak M , Shannon R M , Spiewak R , Theureau G , van Straten W , Wex N , Oswald L S , Posselt B , Sobey C , Barr E D , Camilo F , Hugo B , Jameson A , Johnston S , Karastergiou A , Keith M , Osłowski S 
Published: February 2021

ABSTRACT
We describe the ongoing Relativistic Binary programme (RelBin), a part of the MeerTime large survey project with the MeerKAT radio telescope. RelBin is primarily focused on observations of relativistic effects in binary pulsars to enable measurements of neutron star masses and tests of theories of gravity. We selected 25 pulsars as an initial high priority list of targets based on their characteristics and observational history with other telescopes. In this paper, we provide an outline of the programme, and present polarization calibrated pulse profiles for all selected pulsars as a reference catalogue along with updated dispersion measures. We report Faraday rotation measures for 24 pulsars, twelve of which have been measured for the first time. More than a third of our selected pulsars show a flat position angle swing confirming earlier observations. We demonstrate the ability of the Rotating Vector Model, fitted here to seven binary pulsars, including the Double Pulsar (PSR J0737–3039A), to obtain information about the orbital inclination angle. We present a high time resolution light curve of the eclipse of PSR J0737–3039A by the companion’s magnetosphere, a high-phase-resolution position angle swing for PSR J1141–6545, an improved detection of the Shapiro delay of PSR J1811–2405, and pulse scattering measurements for PSRs J1227–6208, J1757–1854, and J1811–1736. Finally, we demonstrate that timing observations with MeerKAT improve on existing data sets by a factor of, typically, 2–3, sometimes by an order of magnitude.
The excess of cool supergiants from contemporary stellar evolution models defies the metallicity-independent Humphreys–Davidson limit
Authors: Gilkis Avishai , Shenar Tomer , Ramachandran Varsha , Jermyn Adam S , Mahy Laurent , Oskinova Lidia M , Arcavi Iair , Sana Hugues 
Published: February 2021

ABSTRACT
The Humphreys–Davidson (HD) limit empirically defines a region of high luminosities (log10(L/L⊙) ≳ 5.5) and low effective temperatures ($T_{\rm eff} \lesssim 20 \, {\rm kK}$) on the Hertzsprung–Russell diagram in which hardly any supergiant stars are observed. Attempts to explain this limit through instabilities arising in near- or super-Eddington winds have been largely unsuccessful. Using modern stellar evolution, we aim to re-examine the HD limit, investigating the impact of enhanced mixing on massive stars. We construct grids of stellar evolution models appropriate for the Small Magellanic Cloud (SMC) and Large Magellanic Cloud (LMC), as well as for the Galaxy, spanning various initial rotation rates and convective overshooting parameters. Significantly enhanced mixing apparently steers stellar evolution tracks away from the region of the HD limit. To quantify the excess of overluminous stars in stellar evolution simulations, we generate synthetic populations of massive stars and make detailed comparisons with catalogues of cool ($T_\mathrm{eff} \le 12.5\, \mathrm{kK}$) and luminous (log10(L/L⊙) ≥ 4.7) stars in the SMC and LMC. We find that adjustments to the mixing parameters can lead to agreement between the observed and simulated red supergiant populations, but for hotter supergiants the simulations always overpredict the number of very luminous (log10(L/L⊙) ≥ 5.4) stars compared to observations. The excess of luminous supergiants decreases for enhanced mixing, possibly hinting at an important role mixing has in explaining the HD limit. Still, the HD limit remains unexplained for hotter supergiants.
High-contrast and resolution near-infrared photometry of the core of R136
Authors: Khorrami Zeinab , Langlois Maud , Clark Paul C , Vakili Farrokh , Buckner Anne S M , Gonzalez Marta , Crowther Paul , Wünsch Richard , Palouš Jan , Lumsden Stuart , Moraux Estelle 
Published: February 2021

ABSTRACT
We present the sharpest and deepest near-infrared photometric analysis of the core of R136, a newly formed massive star cluster at the centre of the 30 Doradus star-forming region in the Large Magellanic Cloud. We used the extreme adaptive optics of the SPHERE focal instrument implemented on the ESO Very Large Telescope and operated in its IRDIS imaging mode for the second time with longer exposure time in the H and K filters. Our aim was to (i) increase the number of resolved sources in the core of R136, and (ii) to compare with the first epoch to classify the properties of the detected common sources between the two epochs. Within the field of view (FOV) of 10.8″ × 12.1″ ($2.7\,\text {pc}\times 3.0\, \text {pc}$), we detected 1499 sources in both H and K filters, for which 76 per cent of these sources have visual companions closer than 0.2″. The larger number of detected sources enabled us to better sample the mass function (MF). The MF slopes are estimated at ages of 1, 1.5, and 2 Myr, at different radii, and for different mass ranges. The MF slopes for the mass range of 10–300 M⊙ are about 0.3 dex steeper than the mass range of 3–300 M⊙, for the whole FOV and different radii. Comparing the JHK colours of 790 sources common in between the two epochs, 67 per cent of detected sources in the outer region (r &gt; 3″) are not consistent with evolutionary models at 1–2 Myr and with extinctions similar to the average cluster value, suggesting an origin from ongoing star formation within 30 Doradus, unrelated to R136.
Evidence that short-period AM CVn systems are diverse in outburst behaviour
Authors: Duffy C , Ramsay G , Steeghs D , Dhillon V , Kennedy M R , Mata Sánchez D , Ackley K , Dyer M , Lyman J , Ulaczyk K , Galloway D K , O’Brien P , Noysena K , Nuttall L , Pollacco D 
Published: February 2021

ABSTRACT
We present results of our analysis of up to 15 yr of photometric data from eight AM CVn systems with orbital periods between 22.5 and 26.8 min. Our data have been collected from the GOTO, ZTF, Pan-STARRS, ASAS-SN, and Catalina all-sky surveys and amateur observations collated by the AAVSO. We find evidence that these interacting ultracompact binaries show a similar diversity of long-term optical properties as the hydrogen accreting dwarf novae. We found that AM CVn systems in the previously identified accretion disc instability region are not a homogenous group. Various members of the analysed sample exhibit behaviour reminiscent of Z Cam systems with long superoutbursts (SOs) and standstills, SU UMa systems with regular, shorter SOs, and nova-like systems that appear only in a high state. The addition of TESS full frame images of one of these systems, KL Dra, reveals the first evidence for normal outbursts appearing as a precursor to SOs in an AM CVn system. Our results will inform theoretical modelling of the outbursts of hydrogen deficient systems.
Density profile evolution during prestellar core collapse: collapse starts at the large scale
Authors: Gómez Gilberto C , Vázquez-Semadeni Enrique , Palau Aina 
Published: February 2021

ABSTRACT
We study the gravitationally dominated, accretion-driven evolution of a prestellar core. In our model, as the core’s density increases, it remains immersed in a constant-density environment and so it accretes from this environment, increasing its mass and reducing its Jeans length. Assuming a power-law density profile ρ ∝ r−p, we compute the rate of change of the slope p, and show that the value p = 2 is stationary, and furthermore, an attractor. The radial profile of the Jeans length scales as rp/2, implying that, for p &lt; 2, there is a radius below which the region is smaller than its Jeans length, thus appearing gravitationally stable and in need of pressure confinement, while, in reality, it is part of a larger scale collapse and is undergoing compression by the infalling material. In this region, the infall speed decreases towards the centre, eventually becoming subsonic, thus appearing ‘coherent’, without the need for turbulence dissipation. We present a compilation of observational determinations of density profiles in dense cores and show that the distribution of their slopes peaks at p ∼ 1.7–1.9, supporting the notion that the profile steepens over time. Finally, we discuss the case of magnetic support in a core in which the field scales as B ∝ ρβ. For the expected value of β = 2/3, this implies that the mass to magnetic flux ratio also decreases towards the central parts of the cores, making them appear magnetically supported, while, in reality, they may be part of larger collapsing supercritical region. We conclude that local signatures of either thermal or magnetic support are not conclusive evidence of stability, that the gravitational instability of a region must be established at the large scales, and that the prestellar stage of collapse is dynamic rather than quasi-static.
A finite volume method for two-moment cosmic ray hydrodynamics on a moving mesh
Authors: Thomas T , Pfrommer C , Pakmor R 
Published: February 2021

ABSTRACT
We present a new numerical algorithm to solve the recently derived equations of two-moment cosmic ray hydrodynamics (CRHD). The algorithm is implemented as a module in the moving mesh Arepo code. Therein, the anisotropic transport of cosmic rays (CRs) along magnetic field lines is discretized using a path-conservative finite volume method on the unstructured time-dependent Voronoi mesh of Arepo. The interaction of CRs and gyroresonant Alfvén waves is described by short time-scale source terms in the CRHD equations. We employ a custom-made semi-implicit adaptive time stepping source term integrator to accurately integrate this interaction on the small light-crossing time of the anisotropic transport step. Both the transport and the source term integration step are separated from the evolution of the magnetohydrodynamical equations using an operator split approach. The new algorithm is tested with a variety of test problems, including shock tubes, a perpendicular magnetized discontinuity, the hydrodynamic response to a CR overpressure, CR acceleration of a warm cloud, and a CR blast wave, which demonstrate that the coupling between CR and magnetohydrodynamics is robust and accurate. We demonstrate the numerical convergence of the presented scheme using new linear and non-linear analytic solutions.
Testing models of periodically modulated FRB activity
Authors: Katz J I 
Published: February 2021

ABSTRACT
The activity of the repeating FRB 20180916B is periodically modulated with a period of 16.3 d, and FRB 121102 may be similarly modulated with a period of about 160 d. In some models of this modulation, the period derivative is insensitive to the uncertain parameters; these models can be tested by measurement of or bounds on the derivative. In other models, values of the uncertain parameters can be constrained. Periodic modulation of aperiodic bursting activity may result from emission by a narrow beam wandering within a cone or funnel along the axis of a precessing disc, such as the accretion discs in X-ray binaries. The production of FRB 200428 by a neutron star that is neither accreting nor in a binary then shows universality: coherent emission occurring in a wide range of circumstances.
Exploring the planetary-mass population in the Upper Scorpius association
Authors: Lodieu N , Hambly N C , Cross N J G 
Published: February 2021

ABSTRACT
We aim at identifying very low-mass isolated planetary-mass member candidates in the nearest OB association to the Sun, Upper Scorpius (USco) (145 pc; 5–10 Myr), to constrain the form and shape of the luminosity function and mass spectrum in this regime. We conducted a deep multiband (Y = 21.2, J = 20.5, Z = 22.0 mag) photometric survey of 6 deg2 in the central region of USco. We extend the current sequence of astrometric and spectroscopic members by about two magnitudes in Y and one magnitude in J, reaching potentially T-type free-floating members in the association with predicted masses below 5 Jupiter masses, well into the planetary-mass regime. We extracted a sample of 57 candidates in this area and present infrared spectroscopy confirming two of them as young L-type members with characteristic spectral features of 10-Myr-old brown dwarfs. Among the 57 candidates, we highlight 10 new candidates fainter than the coolest members previously confirmed spectroscopically. We do not see any obvious sign of decrease in the mass spectrum of the association, suggesting that star processes can form substellar objects with masses down to 4–5 Jupiter masses.
Formation of supermassive black hole seeds in nuclear star clusters via gas accretion and runaway collisions
Authors: Das Arpan , Schleicher Dominik R G , Leigh Nathan W C , Boekholt Tjarda C N 
Published: February 2021

ABSTRACT
More than 200 supermassive black holes (SMBHs) of masses $\gtrsim 10^9\, \mathrm{M_{\odot }}$ have been discovered at z ≳ 6. One promising pathway for the formation of SMBHs is through the collapse of supermassive stars (SMSs) with masses $\sim 10^{3}{-}10^{5} \, \mathrm{M_{\odot }}$ into seed black holes which could grow upto few times $10^9\, \mathrm{M_{\odot }}$ SMBHs observed at z ∼ 7. In this paper, we explore how SMSs with masses $\sim 10^{3}{-}10^{5} \, \mathrm{M_{\odot }}$ could be formed via gas accretion and runaway stellar collisions in high-redshift, metal-poor nuclear star clusters (NSCs) using idealized N-body simulations. We explore physically motivated accretion scenarios, e.g. Bondi–Hoyle–Lyttleton accretion and Eddington accretion, as well as simplified scenarios such as constant accretions. While gas is present, the accretion time-scale remains considerably shorter than the time-scale for collisions with the most massive object (MMO). However, overall the time-scale for collisions between any two stars in the cluster can become comparable or shorter than the accretion time-scale, hence collisions still play a crucial role in determining the final mass of the SMSs. We find that the problem is highly sensitive to the initial conditions and our assumed recipe for the accretion, due to the highly chaotic nature of the problem. The key variables that determine the mass growth mechanism are the mass of the MMO and the gas reservoir that is available for the accretion. Depending on different conditions, SMSs of masses $\sim 10^{3}{-}10^{5} \, \mathrm{M_{\odot }}$ can form for all three accretion scenarios considered in this work.
Maximum mass of hybrid star formed via shock-induced phase transition in cold neutron stars
Authors: Mallick Ritam , Singh Shailendra , Nandi Rana 
Published: February 2021

ABSTRACT
This paper studies the maximum mass limit of the hybrid star formed after the shock-induced phase transition of a cold neutron star. By employing hadronic and quark equation of state that satisfies the current mass bound, we use combustion adiabat conditions to find such a limit. The combustion adiabat condition results in a local or a global maximum pressure at an intermediate density range. The maximum pressure corresponds to a local or global maximum mass for the phase transformed hybrid star. The phase transition is usually exothermic if we have a local maximum mass. The criteria for exothermic or endothermic phase transition depend on whether the quark pressure/energy ratios to nuclear pressure/energy are smaller or greater than 1. We find that exothermic phase transition in a cold neutron star usually results in hybrid stars whose mass is smaller than a parent neutron star. The phase transition is endothermic for a global maximum pressure; thereby, one gets a global maximum mass. Hybrid stars much massive than phase transformed local maximum mass can be formed, provided there is some external energy source during the phase transition process. However, for some cases, even massive hybrid stars can form with exothermic phase transition for equations of state having global maximum pressure.