bluuebunny/crossref_metadata_2025 huggingface dataset:
AFGL 5180 and AFGL 6366S: sites of hub–filament systems at the opposite edges of a filamentary cloud
Authors: Maity A K , Dewangan L K , Bhadari N K , Ojha D K , Chen Z , Pandey Rakesh
Published: June 2023

We present a multiscale and multiwavelength study to unveil massive star formation (MSF) processes around sites AFGL 5180 and AFGL 6366S, both hosting a Class ii 6.7 GHz methanol maser emission. The radio continuum map at 8.46 GHz reveals a small cluster of radio sources towards AFGL 5180. Signatures of the early stages of MSF in our target sites are spatially seen at the opposite edges of a filamentary cloud (length ∼5 pc), which is observed in the submillimetre dust continuum maps. Using the near-infrared photometric data, the spatial distribution of young stellar objects is found towards the entire filament, primarily clustered at its edges. The getsf utility on the Herschel far-infrared images reveals a hub–filament system (HFS) towards each target site. The analysis of the molecular line data, which benefits from large area coverage (∼1° × 1°), detects two cloud components with a connection in both position and velocity space. This supports the scenario of a cloud–cloud collision (CCC) that occurred ∼1 Myr ago. The filamentary cloud, connecting AFGL 5180 and AFGL 6366S, seems spatially close to an H ii region Sh 2−247 excited by a massive O9.5 star. Based on the knowledge of various pressures exerted by the massive star on its surroundings, the impact of its energetic feedback on the filamentary cloud is found to be insignificant. Overall, our observational outcomes favour the possibility of the CCC scenario driving MSF and the formation of HFSs towards the target sites.
A synthetic Roman Space Telescope High-Latitude Time-Domain Survey: supernovae in the deep field
Authors: Wang Kevin X , Scolnic Dan , Troxel M A , Rodney Steven A , Popovic Brodie , Duff Caleb , Filippenko Alexei V , Foley Ryan J , Hounsell Rebekah , Jha Saurabh W , Jones David O , Joshi Bhavin A , Long Heyang , Macias Phillip , Riess Adam G , Rose Benjamin M , Yamamoto Masaya
Published: June 2023

NASA will launch the Nancy Grace Roman Space Telescope (hereafter Roman) in the second half of this decade, which will allow for a generation-defining measurement of dark energy through multiple probes, including Type Ia supernovae (SNe Ia). To improve decisions on survey strategy, we have created the first simulations of realistic Roman images that include artificial SNe Ia injected as point sources in the images. Our analysis combines work done on Roman simulations for weak gravitational lensing studies as well as catalogue-level simulations of SN Ia samples. We have created a time series of images over 2 yr containing ∼1050 SNe Ia, covering a 1 deg2 subarea of a planned 5 deg2 deep survey. We have released these images publicly for community use along with input catalogues of all injected sources. We create secondary products from these images by generating coadded images and demonstrating recovery of transient sources using image subtraction. We perform first-use analyses on these images in order to measure galaxy detection efficiency, point source detection efficiency, and host-galaxy association biases. The simulated images can be found here at https://roman.ipac.caltech.edu/sims/SN_Survey_Image_sim.html.
Machine learning and galaxy morphology: for what purpose?
Authors: Fraix-Burnet D
Published: June 2023

Classification of galaxies is traditionally associated with their morphologies through visual inspection of images. The amount of data to come render this task, inhuman and Machine Learning (mainly Deep Learning) has been called to the rescue for more than a decade. However, the results look mitigate and there seems to be a shift away from the paradigm of the traditional morphological classification of galaxies. In this paper, I want to show that the algorithms indeed are very sensitive to the features present in images, features that do not necessarily correspond to the Hubble or de Vaucouleurs vision of a galaxy. However, this does not preclude to get the correct insights into the physics of galaxies. I have applied a state-of-the-art ‘traditional’ Machine Learning clustering tool, called Fisher-EM, a latent discriminant subspace Gaussian mixture model algorithm to 4458 galaxies carefully classified into 18 types by the EFIGI project. The optimum number of clusters given by the integrated complete likelihood criterion is 47. The correspondence with the EFIGI classification is correct, but it appears that the Fisher-EM algorithm gives a great importance to the distribution of light which translates to characteristics such as the bulge to disc ratio, the inclination or the presence of foreground stars. The discrimination of some physical parameters (bulge-to-total luminosity ratio, (B–V)T, intrinsic diameter, presence of flocculence or dust, and arm strength) is very comparable in the two classifications.
Timing analysis of the new black hole candidate MAXI J1803−298 with Insight–HXMT and NICER
Authors: Zhu Haifan , Chen Xiao , Wang Wei
Published: June 2023

We present the timing analysis results of MAXI J1803−298, a black hole candidate, during its 2021 outburst using data obtained from the Insight–Hard X-ray Modulation Telescope (Insight–HXMT) and the Neutron star Interior Composition Explorer (NICER). Our analysis reveals that the source undergoes a state transition from the low hard state to the hard intermediate state, followed by the soft intermediate state, ultimately reaching the high soft state. We searched for the quasi-periodic oscillations (QPOs) and studied the characteristics of the outburst. At the beginning of the outburst, the source was in the hard state, many type-C QPOs were seen in the Insight–HXMT data, and the frequency of these QPOs increased from ∼0.16 to 2.6 Hz. Our analysis of the rms–frequency relationship of the type-C QPOs indicates a turning point in the frequency. We also analysed the phase lag versus frequency and energy relationship and deduced that the source likely has a high inclination angle, consistent with previous research. The observed rms and phase-lag features in type-C QPOs could be explained by the Lense–Thirring precession model, although alternatives would be still viable. The lag spectrum of type-B QPOs exhibits a U-shaped pattern similar to that of many other sources, and the type-B QPOs’ rms increases as the energy increases. This phenomenon can be explained by the dual-corona model.
Life after AGN switch off: evolution and properties of fossil galactic outflows
Authors: Zubovas Kastytis , Maskeliūnas Gediminas
Published: June 2023

Galaxy-wide outflows driven by active galactic nuclei (AGN) are an important ingredient in galaxy evolution. Analytical calculations suggest that such outflows have significant inertia and can persist long after the AGN itself fades away. We use hydrodynamical simulations of outflows in idealized galaxy bulges to investigate the propagation of these ‘fossil’ AGN outflows. We find that fossil outflows should be common in gas-poor galaxies but form only rarely in gas-rich ones; in general, fossil outflows should outnumber driven ones by a factor of a few in the local Universe, and possibly more at high redshift. When they do form, fossil outflows tend to be lopsided and detached from the nucleus, and colder than their driven counterparts, with a more prominent molecular phase. Spatially resolved and/or multiphase observations can help distinguish fossil AGN outflows from star formation-driven ones, which have similar integrated properties. We discuss a number of spatially-resolved observations of outflows, suggesting that most show evidence of fossil outflow existence, sometimes together with driven outflows on smaller scales.
High-energy cosmic rays and gamma-rays from star clusters: the case of Cygnus OB2
Authors: Blasi Pasquale , Morlino Giovanni
Published: June 2023

We investigate the acceleration of cosmic rays at the termination shock that results from the interaction of the collective wind of star clusters with the surrounding interstellar medium. The solution of the transport equation of accelerated particles in the wind-excavated cavity, including energy losses due to CR interactions with neutral gas in the bubble, shows several interesting properties that are discussed in detail. The issue of the maximum energy of the accelerated particles is discussed with special care, because of its implications for the origin of Galactic cosmic rays. Gamma-ray emission is produced in the cavity due to inelastic pp scattering, while accelerated particles are advected downstream of the termination shock and diffuse at the same time. Both the spectrum and the morphology of such emission are discussed, with a comparison of our results with the observations of gamma-ray emission from the Cygnus OB2 region.
A theoretic analysis of magnetoactive GES-based turbulent solar plasma instability
Authors: Das Souvik , Atteya Ahmed , Karmakar Pralay Kumar
Published: June 2023

A recently reported gravito-electrostatic sheath (GES) model is procedurally applied to study the turbumagnetoactive helioseismic oscillation features in the entire bi-fluidic solar plasma system. The bounded solar interior plasma (SIP, internally self-gravitating), and the unbounded solar wind plasma (SWP, externally point-gravitating) are coupled through the interfacial diffused solar surface boundary (SSB) due to an exact gravito-electrostatic interplay. A numerical platform on the developed theoretic formalism reveals the evolution of both dispersive and non-dispersive features of the modified GES mode fluctuations in new parametric windows. Different colourspectral profiles exhibit important features of the GES-based SIP–SWP perturbations elaborately. It is illustratively shown that the thermostatistical GES stability depends mainly on the radial distance, magnetic field, equilibrium plasma density, and plasma temperature. We see that their dispersive features are more pertinently pronounced in the self-gravitational domains (SIP) than the electrostatic counterparts (SWP). Besides, different characteristic parameters with accelerating (or decelerating) and stabilizing (or destabilizing) effects influencing the entire solar plasma stability are illustratively portrayed. We speculate that, in the SIP, the long-wave (gravitational-like) helioseismic fluctuations become highly dispersive showing more propagatory nature than the shorter ones (acoustic-like). The short waves show more propagatory propensity than the longer ones in the SSB and SWP regime. The reliability of our proposed investigation is bolstered along with the tentative applicability and future scope in light of the current solar observational scenarios, such as SOHO, STEREO, SDO, PSP, and SolO.
Application of the binary spectral model to high-resolution spectra. First estimation of the fundamental parameters for HD 20784
Authors: Kovalev Mikhail , Straumit Ilya
Published: June 2023

In this paper, we applied previously developed method of binary spectral model fitting to the high-resolution spectra of HD 20784. Simultaneously analysing all three available epochs, we found spectroscopic parameters for both components of the system. These parameters are consistent with stellar evolution model’s predictions and analysis of the photometrical data from Transiting Exoplanets Survey Satellite (TESS).
NuSTAR investigation of X-ray variability and hard X-ray spectral properties in IGR J16320-4751 and IGR J16479-4514
Authors: Bahal Varun , Raman Gayathri
Published: June 2023

We present the results obtained from a comprehensive timing and spectral study of two high mass X-ray binary sources using NuSTAR observations. These two sources, IGR J16320-4751 and IGR J16479-4514 were discovered by INTEGRAL and have been characterizated for the first time in the hard X-ray band (beyond 10 keV) in this work. In these sources, we observe the occurrence of intense X-ray flares, with average luminosities exceeding 1036 erg s−1. Our analysis reveals that these flares can be described consistently in the quasi-spherical accretion regime. The orbital phase of the first flare in NuSTAR observation of IGR J16479-4514 matches with the orbital phases of previous flares (φ = 0.35) in this source detected by other telescopes. We conclude that this flare occurs as a result of the periastron passage of the neutron star, rather than due to the presence of a corotating interaction region (CIR). Furthermore, from the energy-resolved pulse profile analysis of IGR J16320-4751, we find that the pulse fraction is lower in hard X-rays compared to the soft X-rays. We present the hard X-ray spectral parameters of these two sources using several standard spectral model components. We do not detect a cyclotron absorption feature in either target. We provide estimates to the surface magnetic field strength of NS in IGR J16320-4751 using two indirect methods. Lastly, we observe spectral hardening during flaring segments compared to the off-flaring segments which indicates that comptonization is more effective during the flaring segments.
A matched-filter approach to radio variability and transients: searching for orphan afterglows in the VAST Pilot Survey
Authors: Leung James K , Murphy Tara , Lenc Emil , Edwards Philip G , Ghirlanda Giancarlo , Kaplan David L , O’Brien Andrew , Wang Ziteng
Published: June 2023

Radio transient searches using traditional variability metrics struggle to recover sources whose evolution time-scale is significantly longer than the survey cadence. Motivated by the recent observations of slowly evolving radio afterglows at gigahertz frequency, we present the results of a search for radio variables and transients using an alternative matched-filter approach. We designed our matched-filter to recover sources with radio light curves that have a high-significance fit to power-law and smoothly broken power-law functions; light curves following these functions are characteristic of synchrotron transients, including ‘orphan’ gamma-ray burst afterglows, which were the primary targets of our search. Applying this matched-filter approach to data from Variables and Slow Transients Pilot Survey conducted using the Australian SKA Pathfinder, we produced five candidates in our search. Subsequent Australia Telescope Compact Array observations and analysis revealed that: one is likely a synchrotron transient; one is likely a flaring active galactic nucleus, exhibiting a flat-to-steep spectral transition over 4 months; one is associated with a starburst galaxy, with the radio emission originating from either star formation or an underlying slowly evolving transient; and the remaining two are likely extrinsic variables caused by interstellar scintillation. The synchrotron transient, VAST J175036.1–181454, has a multifrequency light curve, peak spectral luminosity, and volumetric rate that is consistent with both an off-axis afterglow and an off-axis tidal disruption event; interpreted as an off-axis afterglow would imply an average inverse beaming factor $\langle f^{-1}_{\text{b}} \rangle = 860^{+1980}_{-710}$, or equivalently, an average jet opening angle of $\langle \theta _{\textrm {j}} \rangle = 3^{+4}_{-1}\,$ deg.
Carbon-enhanced metal-poor star candidates from BP/RP spectra in Gaia DR3
Authors: Lucey Madeline , Al Kharusi Nariman , Hawkins Keith , Ting Yuan-Sen , Ramachandra Nesar , Price-Whelan Adrian M , Beers Timothy C , Lee Young Sun , Yoon Jinmi
Published: June 2023

Carbon-enhanced metal-poor (CEMP) stars comprise almost a third of stars with [Fe/H] < −2, although their origins are still poorly understood. It is highly likely that one sub-class (CEMP-s stars) is tied to mass-transfer events in binary stars, while another sub-class (CEMP-no stars) are enriched by the nucleosynthetic yields of the first generations of stars. Previous studies of CEMP stars have primarily concentrated on the Galactic halo, but more recently they have also been detected in the thick disc and bulge components of the Milky Way. Gaia DR3 has provided an unprecedented sample of over 200 million low-resolution (R ≈ 50) spectra from the BP and RP photometers. Training on the CEMP catalogue from the SDSS/SEGUE database, we use XGBoost to identify the largest all-sky sample of CEMP candidate stars to date. In total, we find 58 872 CEMP star candidates, with an estimated contamination rate of 12 per cent. When comparing to literature high-resolution catalogues, we positively identify 60–68 per cent of the CEMP stars in the data, validating our results and indicating a high completeness rate. Our final catalogue of CEMP candidates spans from the inner to outer Milky Way, with distances as close as r ∼ 0.8 kpc from the Galactic centre, and as far as r > 30 kpc. Future higher resolution spectroscopic follow-up of these candidates will provide validations of their classification and enable investigations of the frequency of CEMP-s and CEMP-no stars throughout the Galaxy, to further constrain the nature of their progenitors.
Hierarchical triple mergers: testing Hawking’s area theorem with the inspiral signals
Authors: Tang Shao-Peng , Fan Yi-Zhong , Wei Da-Ming
Published: June 2023

Hawking’s area theorem is one of the fundamental laws of black holes (BHs), which has been tested at a confidence level of $\sim 95~{{\ \rm per\ cent}}$ with gravitational wave (GW) observations by analysing the inspiral and ringdown portions of GW signals, independently. In this work, we propose to carry out the test in a new way with the hierarchical triple merger (i.e. two successive BH mergers occurred sequentially within the observation window of GW detectors), for which the properties of the progenitor BHs and the remnant BH of the first coalescence can be inferred from the inspiral portions of the two mergers. As revealed in our simulations, the BH area law can be well confirmed for some plausible hierarchical triple merger events detectable in LIGO/Virgo/KAGRA/LIGO-India’s O4/O5 runs. Our proposed method provides significant facilitation for testing the area law and complements previous methods.
A T-Dwarf candidate from JWST early release NIRCam data
Authors: Wang Po-Ya , Goto Tomotsugu , Ho Simon C-C , Lin Yu-Wei , Wu Cossas K-W , Ling Chih-Teng , Hashimoto Tetsuya , Kim Seong Jin , Hsiao Tiger Y-Y
Published: June 2023

We present a distant T-type brown dwarf candidate at ≈2.55 kpc discovered in the Cosmic Evolution Early Release Science (CEERS) fields by James Webb Space Telescope (JWST) NIRCam. In addition to the superb sensitivity, we utilised 7 filters from JWST in near-IR and thus is advantageous in finding faint, previously unseen brown dwarfs. From the model spectra in new JWST/NIRCam filter wavelengths, the selection criteria of F115W-F277W<-0.8 and F277W-F444W>1.1 were chosen to target the spectrum features of brown dwarfs having temperatures from 500 K to 1300 K. Searching through the data from Early Release Observations (ERO) and Early Release Science (ERS), we find 1 promising candidate in the CEERS field. The result of SED fitting suggested an early T spectral type with a low effective temperature of Teff ≈1300 K, the surface gravity of log g ≈ 5.25 cms−2, and an eddy diffusion parameter of logKzz ≈ 7 cm2s−1, which indicates an age of ≈1.8 Gyr and a mass of ≈0.05 M⊙. In contrast to typically found T dwarf within several hundred parsecs, the estimated distance of the source is ≈2.55 kpc, showing the JWST’s power to extend the search to a much larger distance.
Suppression of the inclination instability in the trans-Neptunian Solar system
Authors: Das Arnav , Batygin Konstantin
Published: June 2023

The trans-Neptunian scattered disc exhibits unexpected dynamical structure, ranging from an extended dispersion of perihelion distance to a clustered distribution in orbital angles. Self-gravitational modulation of the scattered disc has been suggested in the literature as an alternative mechanism to Planet nine for sculpting the orbital architecture of the trans-Neptunian region. The numerics of this hypothesis have hitherto been limited to N < O(103) superparticle simulations that omit direct gravitational perturbations from the giant planets and instead model them as an orbit-averaged (quadrupolar) potential, through an enhanced J2 moment of the central body. For sufficiently massive discs, such simulations reveal the onset of collective dynamical behaviour – termed the ‘inclination instability’ – wherein orbital circularisation occurs at the expense of coherent excitation of the inclination. Here, we report N = O(104) GPU-accelerated simulations of a self-gravitating scattered disc (across a range of disc masses spanning 5–40 M⊕) that self-consistently account for intraparticle interactions as well as Neptune’s perturbations. Our numerical experiments show that even under the most favourable conditions, the inclination instability never ensues. Instead, due to scattering, the disc depletes. While our calculations show that a transient lopsided structure can emerge within the first few hundreds of Myr, the terminal outcomes of these calculations systematically reveal a scattered disc that is free of any orbital clustering. We conclude thus that the inclination instability mechanism is an inadequate explanation of the observed architecture of the Solar system.
The 3D kinematics of stellar substructures in the periphery of the Large Magellanic Cloud
Authors: Navarrete Camila , Aguado David S , Belokurov Vasily , Erkal Denis , Deason Alis , Cullinane Lara , Carballo-Bello Julio
Published: June 2023

We report the 3D kinematics of 27 Mira-like stars in the northern, eastern, and southern periphery of the Large Magellanic Cloud (LMC), based on Gaia proper motions and a dedicated spectroscopic follow-up. Low-resolution spectra were obtained for more than 40 Mira-like candidates, selected to trace known substructures in the LMC periphery. Radial velocities and stellar parameters were derived for all stars. Gaia data release 3 astrometry and photometry were used to discard outliers, derive periods for those stars with available light curves, and determine their photometric chemical types. The 3D motion of the stars in the reference frame of the LMC revealed that most of the stars, in all directions, have velocities consistent with being part of the LMC disc population, out of equilibrium in the radial and vertical directions. A suite of numerical simulations was used to constrain the most likely past interaction history between the Clouds given the phase-space distribution of our targets. Model realizations in which the Small Magellanic Cloud (SMC) had three pericentric passages around the LMC best resemble the observations. The interaction history of those model realizations has a recent SMC pericentric passage (∼320 Myr ago), preceded by an SMC crossing of the LMC disc at ∼0.97 Gyr ago, having a radial crossing distance of only ∼4.5 kpc. The previous disc crossing of the SMC was found to occur at ∼1.78 Gyr ago, with a similar radial crossing distance of ∼5.6 kpc.
Cosmological measurements from void-galaxy and galaxy-galaxy clustering in the Sloan Digital Sky Survey
Authors: Woodfinden Alex , Percival Will J , Nadathur Seshadri , Winther Hans A , Fraser T S , Massara Elena , Paillas Enrique , Radinović Slađana
Published: June 2023

We present the cosmological implications of measurements of void-galaxy and galaxy-galaxy clustering from the Sloan Digital Sky Survey (SDSS) Main Galaxy Sample (MGS), Baryon Oscillation Spectroscopic Survey (BOSS), and extended BOSS (eBOSS) luminous red galaxy catalogues from SDSS Data Release 7, 12, and 16, covering the redshift range 0.07 < $z$ < 1.0. We fit a standard ΛCDM cosmological model as well as various extensions, including a constant dark energy equation of state not equal to −1, a time-varying dark energy equation of state, and these same models allowing for spatial curvature. Results on key parameters of these models are reported for void-galaxy and galaxy-galaxy clustering alone, both of these combined, and all these combined with measurements from the cosmic microwave background (CMB) and supernovae (SN). For the combination of void-galaxy and galaxy-galaxy clustering, we find tight constraints of Ωm = 0.356 ± 0.024 for a base ΛCDM cosmology, $\Omega _\mathrm{m} = 0.391^{+0.028}_{-0.021}, w = -1.50^{+0.43}_{-0.28}$ additionally allowing the dark energy equation of state $w$ to vary, and $\Omega _\mathrm{m} = 0.331^{+0.067}_{-0.094}, w=-1.41^{+0.70}_{-0.31},\ \mathrm{and}\ \Omega _\mathrm{k} = 0.06^{+0.18}_{-0.13}$ further extending to non-flat models. The combined SDSS results from void-galaxy and galaxy-galaxy clustering in combination with CMB+SN provide a 30 per cent improvement in parameter Ωm over CMB+SN for ΛCDM, a 5 per cent improvement in parameter Ωm when $w$ is allowed to vary, and a 32 per cent and 68 per cent improvement in parameters Ωm and Ωk when allowing for spatial curvature.
Radio variable and transient sources on minute time-scales in the ASKAP pilot surveys
Authors: Wang Yuanming , Murphy Tara , Lenc Emil , Mercorelli Louis , Driessen Laura , Pritchard Joshua , Lao Baoqiang , Kaplan David L , An Tao , Bannister Keith W , Heald George , Lu Shuoying , Tuntsov Artem , Walker Mark , Zic Andrew
Published: June 2023

We present results from a radio survey for variable and transient sources on 15-min time-scales, using the Australian SKA Pathfinder (ASKAP) pilot surveys. The pilot surveys consist of 505 h of observations conducted at around 1 GHz observing frequency, with a total sky coverage of 1476 deg2. Each observation was tracked for approximately 8 – 10 h, with a typical rms sensitivity of ∼30 μJy beam−1 and an angular resolution of ∼12 arcsec. The variability search was conducted within each 8 – 10 h observation on a 15-min time-scale. We detected 38 variable and transient sources. Seven of them are known pulsars, including an eclipsing millisecond pulsar, PSR J2039−5617. Another eight sources are stars, only one of which has been previously identified as a radio star. For the remaining 23 objects, 22 are associated with active galactic nuclei or galaxies (including the five intra-hour variables that have been reported previously), and their variations are caused by discrete, local plasma screens. The remaining source has no multiwavelength counterparts and is therefore yet to be identified. This is the first large-scale radio survey for variables and transient sources on minute time-scales at a sub-mJy sensitivity level. We expect to discover ∼1 highly variable source per day using the same technique on the full ASKAP surveys.
Prospects for localizing Planet 9 with a future Uranus mission
Authors: Bucko Jozef , Soyuer Deniz , Zwick Lorenz
Published: June 2023

Past years have seen various publications attempting to explain the apparent clustering features of trans-Neptunian objects, the most popular explanation being an unconfirmed ‘Planet 9’. The recently proposed Uranus Orbiter and Probe mission by NASA’s Planetary Science and Astrobiology Decadal Survey could offer the opportunity to precisely determine Planet 9’s sky location and mass by carefully monitoring ranging data during the interplanetary cruise. We use Monte Carlo Markov chain methods to reconstruct simulated spacecraft trajectories in a simplified Solar system model containing Planet 9, providing an estimate of the mission’s localization capacity depending on sky location, Earth-spacecraft Doppler link noise level and data collection rate. We characterize the noise via the Allan deviation σA, scaled to the Cassini-era value $\sigma _{\rm A}^{\rm \scriptscriptstyle Cass} = 3 \times 10^{-15}$, finding that daily measurements of the spacecraft position can lead to ∼0.2 deg2 localization of Planet 9 (assuming M9 = 6.3 M⊕, d9 = 460 au). As little as a three-fold improvement in σA drastically decreases the sky localization area size to ∼0.01 deg2. Thus, we showcase that a future Uranus mission carries a significant potential also for non-Uranian science.
Transit time thermalization and the stochastic wave energization of ions in quasi-perpendicular shocks
Authors: Stasiewicz Krzysztof
Published: June 2023

It is shown that the ratio of the proton convective gyroradius rEp, to the width of the shock ramp D, controls the thermalization process of ions in quasi-perpendicular shocks. When rEp/D > 1, the solar wind beam energy is rapidly converted to gyration (thermal) energy by a universal, transit time thermalization (TTT) mechanism that does not require any collisions, waves, or instabilities. The TTT of ions on magnetic field gradients is followed by stochastic wave energization (SWE) on electric field gradients. Ions heated by TTT and SWE processes are subject to additional ballistic surfing acceleration caused by the convection field in the shock front. These three fundamental ion energization mechanisms are studied with test-particle simulations in a realistic shock model, and are shown to be consistent with magnetospheric multiscale measurements in the Earth’s bow shock. It is also shown that shock reflected ions are produced by the SWE process and not by the cross-shock potential. An explanation for downstream oscillations in quasi-perpendicular shocks is also provided.
Cooperativity boosts affinity and specificity of proteins with multiple RNA-binding domains
Authors: Stitzinger Simon H , Sohrabi-Jahromi Salma , Söding Johannes
Published: June 2023

Numerous cellular processes rely on the binding of proteins with high affinity to specific sets of RNAs. Yet most RNA-binding domains display low specificity and affinity in comparison to DNA-binding domains. The best binding motif is typically only enriched by less than a factor 10 in high-throughput RNA SELEX or RNA bind-n-seq measurements. Here, we provide insight into how cooperative binding of multiple domains in RNA-binding proteins (RBPs) can boost their effective affinity and specificity orders of magnitude higher than their individual domains. We present a thermodynamic model to calculate the effective binding affinity (avidity) for idealized, sequence-specific RBPs with any number of RBDs given the affinities of their isolated domains. For seven proteins in which affinities for individual domains have been measured, the model predictions are in good agreement with measurements. The model also explains how a two-fold difference in binding site density on RNA can increase protein occupancy 10-fold. It is therefore rationalized that local clusters of binding motifs are the physiological binding targets of multi-domain RBPs.
Regulation of mature mRNA levels by RNA processing efficiency
Authors: Henfrey Callum , Murphy Shona , Tellier Michael
Published: June 2023

Transcription and co-transcriptional processes, including pre-mRNA splicing and mRNA cleavage and polyadenylation, regulate the production of mature mRNAs. The carboxyl terminal domain (CTD) of RNA polymerase (pol) II, which comprises 52 repeats of the Tyr1Ser2Pro3Thr4Ser5Pro6Ser7 peptide, is involved in the coordination of transcription with co-transcriptional processes. The pol II CTD is dynamically modified by protein phosphorylation, which regulates recruitment of transcription and co-transcriptional factors. We have investigated whether mature mRNA levels from intron-containing protein-coding genes are related to pol II CTD phosphorylation, RNA stability, and pre-mRNA splicing and mRNA cleavage and polyadenylation efficiency. We find that genes that produce a low level of mature mRNAs are associated with relatively high phosphorylation of the pol II CTD Thr4 residue, poor RNA processing, increased chromatin association of transcripts, and shorter RNA half-life. While these poorly-processed transcripts are degraded by the nuclear RNA exosome, our results indicate that in addition to RNA half-life, chromatin association due to a low RNA processing efficiency also plays an important role in the regulation of mature mRNA levels.
Upstream open reading frame-encoded MP31 disrupts the mitochondrial quality control process and inhibits tumorigenesis in glioblastoma
Authors: Huang Nunu , Chen Zhipeng , Yang Xuesong , Gao Yixin , Zhong Jian , Li Yan , Xiao Feizhe , Wang Xiuxing , Shi Yu , Zhang Nu
Published: June 2023

Background

Mitochondrial hyperpolarization achieved by the elevation of mitochondrial quality control (MQC) activity is a hallmark of glioblastoma (GBM). Therefore, targeting the MQC process to disrupt mitochondrial homeostasis should be a promising approach for GBM therapy.

Methods

We used 2-photon fluorescence microscopy, Fluorescence-Activated Cell Sorting, and confocal microscopy with specific fluorescent dyes to detect the mitochondrial membrane potential (MMP) and mitochondrial structures. Mitophagic flux was measured with mKeima.

Results

MP31, a phosphatase and tensin homolog (PTEN) uORF-translated and mitochondria-localized micropeptide, disrupted the MQC process and inhibited GBM tumorigenesis. Re-expression of MP31 in patient-derived GBM cells induced MMP loss to trigger mitochondrial fission but blocked mitophagic flux, leading to the accumulation of damaged mitochondria in cells, followed by reactive oxygen species production and DNA damage. Mechanistically, MP31 inhibited lysosome function and blocked lysosome fusion with mitophagosomes by competing with V-ATPase A1 for lactate dehydrogenase B (LDHB) binding to induce lysosomal alkalinization. Furthermore, MP31 enhanced the sensitivity of GBM cells to TMZ by suppressing protective mitophay in vitro and in vivo, but showed no side effects on normal human astrocytes or microglia cells (MG).

Conclusions

MP31 disrupts cancerous mitochondrial homeostasis and sensitizes GBM cells to current chemotherapy, without inducing toxicity in normal human astrocytes and MG. MP31 is a promising candidate for GBM treatment.
M2 isoform of pyruvate kinase rewires glucose metabolism during radiation therapy to promote an antioxidant response and glioblastoma radioresistance
Authors: Bailleul Justine , Ruan Yangjingyi , Abdulrahman Lobna , Scott Andrew J , Yazal Taha , Sung David , Park Keunseok , Hoang Hanna , Nathaniel Juan , Chu Fang-I , Palomera Daisy , Sehgal Anahita , Tsang Jonathan E , Nathanson David A , Xu Shili , Park Junyoung O , ten Hoeve Johanna , Bhat Kruttika , Qi Nathan , Kornblum Harley I , Schaue Dorthe , McBride William H , Lyssiotis Costas A , Wahl Daniel R , Vlashi Erina
Published: June 2023

Background

Resistance to existing therapies is a significant challenge in improving outcomes for glioblastoma (GBM) patients. Metabolic plasticity has emerged as an important contributor to therapy resistance, including radiation therapy (RT). Here, we investigated how GBM cells reprogram their glucose metabolism in response to RT to promote radiation resistance.

Methods

Effects of radiation on glucose metabolism of human GBM specimens were examined in vitro and in vivo with the use of metabolic and enzymatic assays, targeted metabolomics, and FDG-PET. Radiosensitization potential of interfering with M2 isoform of pyruvate kinase (PKM2) activity was tested via gliomasphere formation assays and in vivo human GBM models.

Results

Here, we show that RT induces increased glucose utilization by GBM cells, and this is accompanied with translocation of GLUT3 transporters to the cell membrane. Irradiated GBM cells route glucose carbons through the pentose phosphate pathway (PPP) to harness the antioxidant power of the PPP and support survival after radiation. This response is regulated in part by the PKM2. Activators of PKM2 can antagonize the radiation-induced rewiring of glucose metabolism and radiosensitize GBM cells in vitro and in vivo.

Conclusions

These findings open the possibility that interventions designed to target cancer-specific regulators of metabolic plasticity, such as PKM2, rather than specific metabolic pathways, have the potential to improve the radiotherapeutic outcomes in GBM patients.
Radiotherapy and radiosurgery for meningiomas
Authors: Chen William C , Lucas Calixto-Hope G , Magill Stephen T , Rogers C Leland , Raleigh David R
Published: June 2023

Meningiomas comprise a histologically and clinically diverse set of tumors arising from the meningothelial lining of the central nervous system. In the past decade, remarkable progress has been made in deciphering the biology of these common neoplasms. Nevertheless, effective systemic or molecular therapies for meningiomas remain elusive and are active areas of preclinical and clinical investigation. Thus, standard treatment modalities for meningiomas are limited to maximal safe resection, radiotherapy, or radiosurgery. This review examines the history, clinical rationale, and future directions of radiotherapy and radiosurgery as integral and effective treatments for meningiomas.
Meningioma in the elderly
Authors: Amoo Michael , Henry Jack , Farrell Michael , Javadpour Mohsen
Published: June 2023

Meningiomas are the most common primary intracranial neoplasm, accounting for approximately 40% of all primary brain tumors. The incidence of meningioma increases with age to 50 per 100,000 in patients older than 85. As the population ages, an increasing proportion of meningioma patients are elderly. Much of this increase is accounted for by an increase in incidental, asymptomatic diagnoses, which have a low risk of progression in the elderly. The first-line treatment of symptomatic disease is resection. Fractionated radiotherapy (RT) or stereotactic radiosurgery (SRS) can be considered as primary treatment where surgery is not feasible, or as adjuvant therapy in cases of subtotal resection or high grade histopathology. The role of RT/SRS, particularly following gross total resection of atypical meningioma, is unclear and requires further evaluation. There is an increased risk of perioperative and postoperative morbidity in the elderly and therefore management decisions must be tailored to individual circumstances. Good functional outcomes can be achieved in selected patients and age alone is not a contraindication to intervention. The immediate postoperative course is an important determinant of prognosis. Therefore, careful preoperative evaluation and avoidance of complications are necessary to optimize outcomes.
The clinical and genomic features of seizures in meningiomas
Authors: Dincer Alper , Jalal Muhammad I , Gupte Trisha P , Vetsa Shaurey , Vasandani Sagar , Yalcin Kanat , Marianayagam Neelan , Blondin Nicholas , Corbin Zachary , McGuone Declan , Fulbright Robert K , Erson-Omay Zeynep , Günel Murat , Moliterno Jennifer
Published: June 2023

Meningiomas are the most common central nervous system tumors. Although these tumors are extra-axial, a relatively high proportion (10%–50%) of meningioma patients have seizures that can substantially impact the quality of life. Meningiomas are believed to cause seizures by inducing cortical hyperexcitability that results from mass effect and cortical irritation, brain invasion, or peritumoral brain edema. In general, meningiomas that are associated with seizures have aggressive features, with risk factors including atypical histology, brain invasion, and higher tumor grade. Somatic NF2 mutated meningiomas are associated with preoperative seizures, but the effect of the driver mutation is mediated through atypical features. While surgical resection is effective in controlling seizures in most patients with meningioma-related epilepsy, a history of seizures and uncontrolled seizures prior to surgery is the most significant predisposing factor for persistent postoperative seizures. Subtotal resection (STR) and relatively larger residual tumor volume are positive predictors of postoperative seizures. Other factors, including higher WHO grade, peritumoral brain edema, and brain invasion, are inconsistently associated with postoperative seizures, suggesting they might be crucial in the development of an epileptogenic focus, but do not appear to play a substantial role after seizure activity has been established. Herein, we review and summarize the current literature surrounding meningioma-related epilepsy and underscore the interaction of multiple factors that relate to seizures in patients with meningioma.
The clinical, genetic, and immune landscape of meningioma in patients with NF2-schwannomatosis
Authors: Gregory Grace E , Islim Abdurrahman I , Hannan Cathal John , Jones Adam P , Hammerbeck-Ward Charlotte , Rutherford Scott A , Freeman Simon R , Lloyd Simon , Kalamarides Michel , Smith Miriam J , Couper Kevin , McBain Catherine A , Jenkinson Michael D , Brough David , King Andrew T , Evans D Gareth , Pathmanaban Omar N
Published: June 2023

NF2-schwannomatosis is the most common genetic predisposition syndrome associated with meningioma. Meningioma in NF2-schwannomatosis is a major source of morbidity and mortality. This is due to accumulative tumor burden in patients with synchronous schwannomas and ependymomas, sometimes including complex collision tumors. Balancing the impact of multiple interventions against the natural history of various index tumors, and the ongoing risk of de novo tumors over an individual’s lifetime makes decision-making complex. The management of any given individual meningioma is often different from a comparable sporadic tumor. There is typically a greater emphasis on conservative management and tolerating growth until a risk boundary is reached, whereby symptomatic deterioration or higher risk from anticipated future treatment is threatened. Management by high-volume multidisciplinary teams improves quality of life and life expectancy. Surgery remains the mainstay treatment for symptomatic and rapidly enlarging meningioma. Radiotherapy has an important role but carries a higher risk compared to its use in sporadic disease. Whilst bevacizumab is effective in NF2-associated schwannoma and cystic ependymoma, it has no value in the management of meningioma. In this review, we describe the natural history of the disease, underlying genetic, molecular, and immune microenvironment changes, current management paradigms, and potential therapeutic targets.
Signal processing for RIS-assisted millimeter-wave/terahertz communications
Authors: Wang Wei , Zhang Wei
Published: June 2023

The model-free and learning-based configuration of RIS is a new signal processing paradigm to overcome the challenges of embracing RIS in millimeter wave/Terahertz communications.
Nicotine Pouch Awareness and Use Among Youth, National Youth Tobacco Survey, 2021
Authors: Kramer Renee D , Park-Lee Eunice , Marynak Kristy L , Jones Jamal T , Sawdey Michael D , Cullen Karen A
Published: June 2023

Introduction

This manuscript examines prevalence of awareness and use of nicotine pouches among U.S. middle and high school students by sociodemographic characteristics and other tobacco product use and characterizes nicotine pouch and other tobacco product use behaviors among current nicotine pouch users.

Aims and Methods

Data are from the 2021 National Tobacco Youth Survey, a cross-sectional, school-based survey of middle and high school students (N = 20 413; overall response rate: 44.6%), which included questions on nicotine pouches in 2021 for the first time. Prevalence estimates, 95% confidence intervals, and estimated population counts were assessed for nicotine pouch awareness, ever use, and current (past 30 days) use, and for use behaviors related to nicotine pouches (frequency of use, flavor(s) used) and other tobacco products (ever, current, frequency of use) among current nicotine pouch users.

Results

Over one-third of students (35.5%) had ever heard of nicotine pouches. An estimated 1.9% (490 000) reported ever using them, while 0.8% (200 000) reported current use. Among current nicotine pouch users, 61.6% reported flavored nicotine pouch use, 64.2% reported current e-cigarette use, and 52.6% used multiple (≥2) tobacco products. Current use of nicotine pouches was common among current smokeless tobacco users (41.3%).

Conclusions

Overall, in 2021, while relatively few students had ever tried nicotine pouches or currently used them, more than one-third had heard of them. Current nicotine pouch users tended to use other tobacco products, particularly e-cigarettes and smokeless tobacco. Given previous rapid increases in youth uptake of e-cigarettes, it is important to continue monitoring nicotine pouch use among young people.

Implications

This study’s findings provide an important baseline for future monitoring of nicotine pouch awareness and use among middle and high school students. Emerging tobacco products, particularly those that are flavored, widely available, discreet, and inexpensive have the potential to attract youth. Given the potential of these products to appeal to young people, ongoing monitoring of nicotine pouch use behaviors is important to inform public health and regulatory efforts.
Relative Effectiveness of the Cell-Based Quadrivalent Influenza Vaccine in Preventing Cardiorespiratory Hospitalizations in Adults Aged 18–64 Years During the 2019–2020 US Influenza Season
Authors: Imran Mahrukh , Puig-Barbera Juan , Ortiz Justin R , Lopez-Gonzalez Lorena , Dean Alex , Bonafede Machaon , Haag Mendel
Published: June 2023

Background

The mammalian cell-based quadrivalent inactivated influenza vaccine (IIV4c) has advantages over egg-based quadrivalent inactivated influenza vaccine (IIV4e), as production using cell-derived candidate viruses eliminates the opportunity for egg adaptation. This study estimated the relative vaccine effectiveness (rVE) of IIV4c versus IIV4e in preventing cardiorespiratory hospitalizations during the 2019–2020 US influenza season.

Methods

We conducted a retrospective cohort study using electronic medical records linked to claims data of US individuals aged 18–64 years. We assessed rVE against cardiorespiratory hospitalizations and against subcategories of this outcome, including influenza, pneumonia, myocardial infarction and ischemic stroke, and respiratory hospitalizations. We used a doubly robust inverse probability of treatment weighting and logistic regression model to obtain odds ratios (ORs; odds of outcome among IIV4c recipients/odds of outcome among IIV4e recipients) adjusted for age, sex, race, ethnicity, geographic region, vaccination week, health status, frailty, and healthcare resource utilization. rVE was calculated as 100(1 − ORadjusted).

Results

In total, 1 491 097 individuals (25.2%) received IIV4c, and 4 414 758 (74.8%) received IIV4e. IIV4c was associated with lower odds of cardiorespiratory (rVE, 2.5% [95% confidence interval, 0.9%–4.1%]), respiratory (3.7% [1.5%–5.8%]), and influenza (9.3% [0.4%–17.3%]) hospitalizations among adults 18–64 years of age. No difference was observed for the other outcomes.

Conclusions

This real-world study conducted for the 2019–2020 season demonstrated that vaccination with IIV4c was associated with fewer cardiorespiratory, respiratory, and influenza hospitalizations compared with IIV4e.
Optimal Frequency of Hepatitis C Virus (HCV) RNA Testing for Detection of Acute HCV Infection Among At-risk People With Human Immunodeficiency Virus: A Multicenter Study
Authors: Sun Hsin-Yun , Liou Bo-Huang , Chen Tun-Chieh , Yang Chia-Jui , Huang Sung-Hsi , Lu Po-Liang , Huang Chung-Hao , Tsai Mao-Song , Cheng Shu-Hsing , Lee Nan-Yao , Ko Wen-Chien , Chen Yen-Hsu , Liu Wang-Da , Lin Shang-Yi , Lin Shih-Ping , Chen Po-Lin , Syue Ling-Shan , Huang Yu-Shan , Chuang Yu-Chung , Chen Cheng-Bin , Chang Ya-Ting , Lee Yuan-Ti , Hsieh Szu-Min , Su Li-Hsin , Cheng Chien-Yu , Hung Chien-Ching
Published: June 2023

Using 3-stage pooled-plasma hepatitis C virus (HCV) RNA testing performed quarterly among at-risk people with human immunodeficiency virus (PWH), we found that if testing had been performed every 6 or 12 months, 58.6%–91.7% of PWH who recently acquired HCV would be delayed for diagnosis and might contribute to onward HCV transmission with longer durations.