bluuebunny/crossref_metadata_2025 huggingface dataset:
Two kinds of enriched topological representations of Q-algebras
Authors: Ruan Xianglong
Published: June 2023

In this paper, we continue the study of the enriched topological representation of $Q$-algebras where $Q$ is a unital quantale and give two kinds of enriched topological representations of $Q$-algebras. The first one is based on strong $M_3$-valued $Q$-algebra homomorphisms, and the second way is based on strong $M_6$-valued $Q$-algebra homomorphisms. For the first way, we first construct a spatial and semiunital $Q$-algebra $M_3$ containing three elements and show that prime elements of semiunital $Q$-algebras are identified with strong $Q$-algebra homomorphisms taking their values in $M_3$. Then we prove that a semiunital $Q$-algebra is spatial iff strong $Q$-algebra homomorphisms with values in $M_3$ separate elements. Based on this, we obtain that every spatial and semiunital $Q$-algebra can be identified with an $M_3$-enriched sober space. For the second enriched topological representation, we construct a spatial and semiunital $Q$-algebra $M_6$ containing exactly six elements and prove that every spatial and semiunital $Q$-algebra can be identified with an $M_6$-enriched sober space.
Multiscale stellar associations across the star formation hierarchy in PHANGS–HST nearby galaxies: methodology and properties
Authors: Larson Kirsten L , Lee Janice C , Thilker David A , Whitmore Bradley C , Deger Sinan , Lilly James , Chandar Rupali , Dale Daniel A , Bigiel Frank , Grasha Kathryn , Groves Brent , Hannon Stephen , Klessen Ralf S , Kreckel Kathryn , Kruijssen J M Diederik , Leroy Adam K , Pan Hsi-An , Rosolowsky Erik , Schinnerer Eva , Schruba Andreas , Watkins Elizabeth J , Williams Thomas G
Published: June 2023

We develop a method to identify and determine the physical properties of stellar associations using Hubble Space Telescope (HST) NUV−U−B−V−I imaging of nearby galaxies from the Physics at High Angular Resolution in Nearby GalaxieS with the Hubble Space Telescope (PHANGS–HST) survey. We apply a watershed algorithm to density maps constructed from point source catalogues Gaussian smoothed to multiple physical scales from 8 to 64 pc. We develop our method on two galaxies that span the distance range in the PHANGS–HST sample: NGC 3351 (10 Mpc) and NGC 1566 (18 Mpc). We test our algorithm with different parameters such as the choice of detection band for the point source catalogue (NUV or V), source density image filtering methods, and absolute magnitude limits. We characterize the properties of the resulting multiscale associations, including sizes, number of tracer stars, number of associations, and photometry, as well as ages, masses, and reddening from spectral energy distribution fitting. Our method successfully identifies structures that occupy loci in the UBVI colour–colour diagram consistent with previously published catalogues of clusters and associations. The median ages of the associations increase from log(age/yr) = 6.6 to log(age/yr) = 6.9 as the spatial scale increases from 8 to 64 pc for both galaxies. We find that the youngest stellar associations, with ages <3 Myr, indeed closely trace H ii regions in H α imaging, and that older associations are increasingly anticorrelated with the H α emission. Owing to our new method, the PHANGS–HST multiscale associations provide a far more complete census of recent star formation activity than found with previous cluster and compact association catalogues.
Seeing sharper and deeper: JWST’s first glimpse of the photometric and spectroscopic properties of galaxies in the epoch of reionization
Authors: Trussler James A A , Adams Nathan J , Conselice Christopher J , Ferreira Leonardo , Austin Duncan , Bhatawdekar Rachana , Caruana Joseph , Frye Brenda L , Harvey Tom , Lovell Christopher C , Pascale Massimo , Roper William J , Verma Aprajita , Vijayan Aswin P , Wilkins Stephen M
Published: June 2023

We analyse the photometric and spectroscopic properties of four galaxies in the epoch of reionization (EoR) within the SMACS J0723.3−7327 JWST Early Release Observations field. Given the known spectroscopic redshifts of these sources, we investigated the accuracy with which photometric redshifts can be derived using NIRCam photometry alone, finding that F115W imaging is essential to distinguish between z ∼ 8 galaxies with high equivalent width (EW) [O iii] λ5007 emission and z ∼ 10 Balmer break galaxies. We find that all four sources exhibit strong (≥0.6 mag) F356W−F444W colours, which sit at the extreme end of theoretical predictions from numerical simulations. We find that these galaxies deviate (by ≈0.5 dex) from the local correlation between [O iii] λ5007/H β and [Ne iii] λ3869/[O ii], which is consistent with the predictions from simulations of high-redshift galaxies having elevated line-excitation ratios. We measure the [O iii] λ5007 rest-frame EWs both directly from the spectroscopy, and indirectly as inferred from the strong F356W−F444W colours, finding large [O iii] λ5007 EWs of 225–1740 Å. The [O iii] λ5007 and H β EWs are consistent with those seen in extreme, intensely star-forming dwarf galaxies in the local Universe. Our structural analysis indicates that these galaxies are resolved, exhibiting irregular shapes with bright clumps. In line with the predictions from the FLARES hydrodynamic simulations, such intense star formation and extreme nebular conditions are likely the norm, rather than the exception, in the EoR.
Lensing of gravitational waves from tidal disruption events
Authors: Toscani Martina , Rossi Elena M , Tamanini Nicola , Cusin Giulia
Published: June 2023

In this work, we investigate the effect of gravitational lensing on the gravitational wave (GW) signals of a population of tidal disruption events (TDEs). We estimate the number of lensed-magnified signals that we expect to detect with future space-based GW observatories, in particular LISA and DECIGO. We model the lens distribution using an hybrid approach that combines semi-analytic methods with numerical results from ray tracing simulations. We divide the TDE population in two classes, nuclear TDEs (main sequence stars tidally disrupted by massive black holes in the cores of galaxies) and globular TDEs (white dwarfs tidally disrupted by intermediate mass black holes in globular clusters). We find that, even considering the effect of lensing, LISA will not be able to observe any TDEs, while DECIGO could detect ∼16 strongly lensed (μ > 2) globular TDEs and ∼135 strongly lensed nuclear TDEs, over an observational period of 10 yr. Our results reveal the role that lensing will play in future deci-Hertz GW observatories, indicating exciting multimessenger opportunities with TDEs but at same time signalling the need to develop adequate data analysis techniques to correctly reconstruct the astrophysical properties of the source.
Galaxy and mass assembly (GAMA): comparing visually and spectroscopically identified galaxy merger samples
Authors: Desmons Alice , Brough Sarah , Martínez-Lombilla Cristina , De Propris Roberto , Holwerda Benne , López-Sánchez Ángel R
Published: June 2023

We conduct a comparison of the merging galaxy populations detected by a sample of visual identification of tidal features around galaxies as well as spectroscopically detected close pairs of galaxies to determine whether our method of selecting merging galaxies biases our understanding of galaxy interactions. Our volume-limited parent sample consists of 852 galaxies from the Galaxy And Mass Assembly (GAMA) survey in the redshift range 0.04 ≤ z ≤ 0.20 and stellar mass range 9.50  ≤  log $_{10}(M_{\star }/\rm {M}_{\odot })\le ~11.0$. We conduct our comparison using images from the Ultradeep layer of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) to visually classify galaxies with tidal features and compare these to the galaxies in the GAMA spectroscopic close-pair sample. We identify 198 galaxies possessing tidal features, resulting in a tidal feature fraction ftidal = 0.23 ± 0.02. We also identify 80 galaxies involved in close pairs, resulting in a close pair fraction fpair = 0.09 ± 0.01. Upon comparison of our tidal feature and close pair samples we identify 42 galaxies that are present in both samples, yielding a fraction fboth = 0.05 ± 0.01. We find evidence to suggest that the sample of close pairs of galaxies is more likely to detect early stage mergers, where two separate galaxies are still visible, and the tidal feature sample detects later-stage mergers, where only one galaxy nucleus remains visible. The overlap of the close pair and tidal feature samples likely detect intermediate-stage mergers. Our results are in good agreement with the predictions of cosmological hydrodynamical simulations regarding the populations of merging galaxies detected by close pair and tidal feature samples.
Hyperfine excitation of 13CCH and C13CH by collisions with para-H2
Authors: Pirlot Jankowiak P , Lique F , Dagdigian P J
Published: June 2023

The computation of hyperfine resolved cross sections and rate coefficients for open-shell molecules in collision with H2 is a true methodological and numerical challenge. Such collisional data are however required to interpret astrophysical observations. We report the first hyperfine resolved rate coefficients for (de-)excitation of 13CCH and C13CH isotopologues induced by collisions with para-H2. These calculations have been performed using a recently published C2H–H2 potential energy surface. Hyperfine resolved cross sections and rate coefficients between the first 98 energy levels of the two isotopologues were determined using a recoupling technique for temperatures ranging from 5 to 100 K. Significant isotopic substitution effects were found, showing the necessity of computing isotopologue specific collisional data. These rate coefficents have then been used in a simple radiative transfer modelling for typical molecular cloud conditions.
sMILES SSPs: a library of semi-empirical MILES stellar population models with variable [α/Fe] abundances
Authors: Knowles Adam T , Sansom A E , Vazdekis A , Allende Prieto C
Published: June 2023

We present a new library of semi-empirical stellar population models that are based on the empirical MILES and semi-empirical sMILES stellar libraries. The models span a large range of age and metallicity, in addition to an [α/Fe] coverage from −0.2 to +0.6 dex, at MILES resolution (FWHM  = $2.5\,$ Å) and wavelength coverage ($3540.5-7409.6\,$ Å). These models are aimed at exploring abundance ratios in the integrated light from stellar populations in star clusters and galaxies. Our approach is to build SSPs from semi-empirical stars at particular [α/Fe] values, thus producing new SSPs at a range of [α/Fe] values from sub-solar to super-solar. We compare these new SSPs with previously published and well-used models and find similar abundance pattern predictions, but with some differences in age indicators. We illustrate a potential application of our new SSPs, by fitting them to the high signal-to-noise data of stacked SDSS galaxy spectra. Age, metallicity, and [α/Fe] trends were measured for galaxy stacks with different stellar velocity dispersions and show systematic changes, in agreement with previous analyses of subsets of those data. These new SSPs are made publicly available.
Self-calibrating optical galaxy cluster selection bias using cluster, galaxy, and shear cross-correlations
Authors: Zeng Chenxiao , Salcedo Andrés N , Wu Hao-Yi , Hirata Christopher M
Published: June 2023

The clustering signals of galaxy clusters are powerful tools for self-calibrating the mass–observable relation and are complementary to cluster abundance and lensing. In this work, we explore the possibility of combining three correlation functions – cluster lensing, the cluster–galaxy cross-correlation function, and the galaxy autocorrelation function – to self-calibrate optical cluster selection bias, the boosted clustering and lensing signals in a richness-selected sample mainly caused by projection effects. We develop mock catalogues of redMaGiC-like galaxies and redMaPPer-like clusters by applying halo occupation distribution models to N-body simulations and using counts-in-cylinders around massive haloes as a richness proxy. In addition to the previously known small-scale boost in projected correlation functions, we find that the projection effects also significantly boost three-dimensional correlation functions to scales of 100 $h^{-1} \, \rm Mpc$. We perform a likelihood analysis assuming survey conditions similar to the Dark Energy Survey and show that the selection bias can be self-consistently constrained at the 10 per cent level. We discuss strategies for applying this approach to real data. We expect that expanding the analysis to smaller scales and using deeper lensing data would further improve the constraints on cluster selection bias.
The winds of young Solar-type stars in the Pleiades, AB Doradus, Columba, and β Pictoris
Authors: Evensberget D , Marsden S C , Carter B D , Salmeron R , Vidotto A A , Folsom C P , Kavanagh R D , Pineda J S , Driessen F A , Strickert K M
Published: June 2023

Solar-type stars, which shed angular momentum via magnetized stellar winds, enter the main sequence with a wide range of rotational periods Prot. This initially wide range of rotational periods contracts and has mostly vanished by a stellar age $t\sim {0.6}\, {\rm Gyr}$, after which Solar-type stars spin according to the Skumanich relation $P_\text{rot}\propto \sqrt{t}$. Magnetohydrodynamic stellar wind models can improve our understanding of this convergence of rotation periods. We present wind models of 15 young Solar-type stars aged ∼24 Myr to ∼0.13 Gyr. With our previous wind models of stars aged ∼0.26 and ∼0.6 Gyr we obtain 30 consistent three-dimensional wind models of stars mapped with Zeeman–Doppler imaging – the largest such set to date. The models provide good cover of the pre-Skumanich phase of stellar spin-down in terms of rotation, magnetic field, and age. We find the mass-loss rate $\dot{M}\propto \Phi ^{{0.9\pm 0.1}}$ with a residual spread of ∼150 per cent and the wind angular momentum loss rate $\dot{J}\propto {}P_\text{rot}^{-1} \Phi ^{1.3\pm 0.2}$ with a residual spread of ∼500 per cent where Φ is the unsigned surface magnetic flux. When comparing different magnetic field scalings for each single star we find a gradual reduction in the power-law exponent with increasing magnetic field strength.
Pulsar glitch in a strangeon star model – III. The recovery
Authors: Lai X Y , Wang W H , Yuan J P , Lu R P , Yue H , Xu R X
Published: June 2023

Strangeon star model has passed various observational tests, such as the massive pulsars and the tidal deformability during binary mergers. Pulsar glitch, as a useful probe for studying the interior structure of pulsars, has also been studied in strangeon star model in our previous papers, including the recovery coefficient, the waiting time of glitches, and glitch activity. In this paper, the recovery process of a glitch is described in the strangeon star model, based on the starquake picture established before (in Paper I). After the starquake, the inner motion of the stellar matter would reduce the tangential pressure in the cracked places at the equatorial plane. The recovery (increase) of the tangential pressure would be achieved by a viscous flow towards the cracked places at equatorial plane, which leads to the exponential recovery of the spin frequency. A uniform viscous flow can reproduce the single exponential decay observed in some glitches, and the viscous time-scale τ and the depth h of the cracking place below the surface can be fitted by the recovery data. It is found that h increases with glitch size Δν/ν, which is expected in the glitch scenario of strangeon stars. The magnitude of the recovery predicted in this recovery model is also consistent with that derived from observations. The single exponential decay reproduced by a uniform viscous flow can be generalized to two or more exponentials by the multicomponent of viscous flows.
Improving pulsar-timing solutions through dynamic pulse fitting
Authors: Nathan Rowina S , Miles Matthew T , Ashton Gregory , Lasky Paul D , Thrane Eric , Reardon Daniel J , Shannon Ryan M , Cameron Andrew D
Published: June 2023

Precision pulsar timing is integral to the detection of the nanohertz stochastic gravitational-wave background as well as understanding the physics of neutron stars. Conventional pulsar timing often uses fixed time and frequency-averaged templates to determine the pulse times of arrival, which can lead to reduced accuracy when the pulse profile evolves over time. We illustrate a dynamic timing method that fits each observing epoch using basis functions. By fitting each epoch separately, we allow for the evolution of the pulse shape epoch to epoch. We apply our method to PSR J1103−5403 and find evidence that it undergoes mode changing, making it the fourth millisecond pulsar to exhibit such behaviour. Our method, which is able to identify and time a single mode, yields a timing solution with a root-mean-square error of $1.343$ µs, a factor of 1.78 improvement over template fitting on both modes. In addition, the white-noise amplitude is reduced 4.3 times, suggesting that fitting the full data set causes the mode changing to be incorrectly classified as white noise. This reduction in white noise boosts the signal-to-noise ratio of a gravitational-wave background signal for this particular pulsar by 32 per cent. We discuss the possible applications for this method of timing to study pulsar magnetospheres and further improve the sensitivity of searches for nanohertz gravitational waves.
The radio shut-off, glitch, and X-ray burst in 1E 1547.0−5408 interpreted through magnetic reconfiguration
Authors: Suvorov Arthur G
Published: June 2023

A short X-ray burst was observed from the radio-loud magnetar 1E 1547.0–5408 in 2022 April. Unusually however, the source stopped showing radio pulsations $\gtrsim 3\,$ weeks prior to the burst. After recovery, radio timing revealed that the object had also undergone a modest glitch. A model for the overall event is constructed where an initially mild perturbation adjusts the magnetic geometry near the polar caps, leading to shallow fractures. Crustal ejecta or particles leaking from a pair-plasma fireball pollute the magnetospheric gaps, shutting off the pulsar mechanism, but the energy release is not yet large enough to noticeably enhance the X-ray flux. This perturbation gradually ramps, eventuating in a large-scale energy redistribution which fuels the burst. The star’s mass quadrupole moment changes in tandem, issuing a glitch. Some quantitative estimates for the magnetic reconfiguration under this interpretation are provided, based on a quasi-static model where the fluid evolves through a sequence of hydromagnetic equilibria.
Search for the Galactic accelerators of cosmic rays up to the knee with the Pevatron test statistic
Authors: Angüner Ekrem Oğuzhan , Spengler Gerrit , Amato Elena , Casanova Sabrina
Published: June 2023

The Pevatron test statistic (PTS) is applied to data from γ-ray observatories to test for the origin of cosmic rays (CRs) at energies around the knee of the CR spectrum. Several sources are analysed within hadronic emission models. Previously derived results for RX J1713.7−3946, Vela Jr, and HESS J1745−290 are confirmed to demonstrate the concept, reliability, and advantages of the PTS. It is excluded with a significance more than 5σ that the sources RX J1713.7−3946 and Vela Jr are Pevatrons, while strong indications exceeding 4σ are found for excluding HESS J1745−290 as a Pevatron. The importance to resolve source confusion with high angular resolution observations for Pevatrons searches is demonstrated using PTS for the region containing the SNR G106.3+2.7 and the Boomerang nebula. No statistically significant conclusion with respect to Pevatron associations could be drawn from this region, for the diffuse γ-ray emission around the Galactic Centre, and the unidentified γ-ray sources LHAASO J2108+5157, HESS J1702−420A, and MGRO J1908+06. Assuming the entire γ-ray emission from MGRO J1908+06 and the tail region of SNR G106.3+2.7 are hadronic, a statistical indication exceeding 3σ is found for the underlying proton spectrum to extend beyond 350–400 TeV as a power law. This result can indicate that these sources are proton and helium Pevatrons, in which the accelerated particles contribute to the knee of proton and helium spectra observed at Earth.
Hybrid deep learning for blazar classification and correlation search with neutrinos
Authors: Ding Jiacheng , Huang Yunlei , Li Xiao-Dong , Wang Xin , Wang Yang , Yang Lili
Published: June 2023

Since the successful discovery of neutrinos, their origin is still a mystery until the association with TXS 0506+056. More messengers are achievable to study the intrinsic mechanism of extreme phenomena. Recently, Fermi-LAT Collaboration published the fourth catalogue of active galactic nuclei (4LAC), together with Data Release 2 later, including totally 3148 sources. The majority of these objects are blazars, which are classified into flat-spectrum radio quasars (FSRQs), BL Lac-type objects (BLLs), and blazars of uncertain type (BCUs) according to their optical observation feature. The BCUs take up to 38.2 per cent of total, whose classification is quite challenging and manpower consuming. However with the remarkable advances of technology, deep learning has been widely applied in astronomy. In this work, we take the advantage of 11 machine learning algorithms plus the convolutional neural network (CNN)-based deep learning algorithm to classify BCUs based on 10 parameters and the broad-band spectral energy distribution of each object obtained with vou-blazars. On average, this method has impressive performance, reaching above 95 per cent of balanced accuracy for the training sample, best among the studies so far. We correlate the IceCube neutrinos and blazars in 4LAC, found a few possible associations. With the machine learning prediction, we later elaborate the association of these BCUs with neutrinos samples and find out most of the BCUs associated with neutrinos are with low synchrotron peak frequency, which may be due to the energy distribution of high-energy particles. We propose neutrinos might be another feature for objects classification in the future.
Evolution of matter and galaxy clustering in cosmological hydrodynamical simulations
Authors: Einasto Jaan , Hütsi Gert , Liivamägi Lauri-Juhan , Park Changbom , Kim Juhan , Szapudi Istvan , Einasto Maret
Published: June 2023

We quantify the evolution of matter and galaxy clustering in cosmological hydrodynamical simulations via correlation and bias functions of matter and galaxies. We use simulations TNG100 and TNG300 with epochs from z = 5 to z = 0. We calculate spatial correlation functions (CFs) of galaxies, ξ(r), for simulated galaxies and dark matter (DM) particles to characterize the evolving cosmic web. We find that bias parameters decrease during the evolution, confirming earlier results. Bias parameters of the lowest luminosity galaxies, b0, estimated from CFs are lower relative to CFs of particle density-limited clustered samples of DM. At low and medium luminosities, bias parameters of galaxies are equal, suggesting that dwarf galaxies reside in the same filamentary web as brighter galaxies. We find that bias parameters b0, estimated from CFs of clustered DM, agree with the expected values from the fraction of particles in the clustered population, b = 1/Fc. The cosmic web contains filamentary structures of various densities, and fractions of matter in the clustered and the unclustered populations are both less than unity. Thus, the CF amplitude of the clustered matter is always higher than that for all matter, i.e. bias parameter must be b > 1. Differences between CFs of galaxies and clustered DM suggest that these functions describe different properties of the cosmic web.
Joint analysis of gravitational-wave and electromagnetic data of mergers: breaking an afterglow model degeneracy in GW170817 and in future events
Authors: Gianfagna Giulia , Piro Luigi , Pannarale Francesco , Van Eerten Hendrik , Ricci Fulvio , Ryan Geoffrey , Troja Eleonora
Published: June 2023

On 2017 August 17, Advanced LIGO and Virgo observed GW170817, the first gravitational-wave (GW) signal from a binary neutron star merger. It was followed by a short-duration gamma-ray burst, GRB 170817A, and by a non-thermal afterglow emission. In this work, a combined simultaneous fit of the electromagnetic (EM, specifically, afterglow) and GW domains is implemented, both using the posterior distribution of a GW standalone analysis as prior distribution to separately process the EM data, and fitting the EM and GW domains simultaneously. These approaches coincide mathematically, as long as the actual posterior of the GW analysis, and not an approximation, is used as prior for the EM analysis. We treat the viewing angle, θv, as shared parameter across the two domains. In the afterglow modelling with a Gaussian structured jet this parameter and the jet core angle, θc, are correlated, leading to high uncertainties on their values. The joint EM + GW analysis relaxes this degeneracy, reducing the uncertainty compared to an EM-only fit. We also apply our methodology to hypothetical GW170817-like events occurring in the next GW observing run at ∼140 and 70 Mpc. At 70 Mpc the existing EM degeneracy is broken, thanks to the inclusion of the GW domain in the analysis. At 140 Mpc, the EM-only fit cannot constrain θv nor θc because of the lack of detections in the afterglow rising phase. Folding the GW data into the analysis leads to tighter constraints on θv, still leaving θc unconstrained, requiring instruments with higher sensitivities, such as Athena.
Eccentricity growth of massive planets inside cavities of protoplanetary discs
Authors: Romanova M M , Koldoba A V , Ustyugova G V , Lai D , Lovelace R V E
Published: June 2023

We carry out hydrodynamical simulations to study the eccentricity growth of a 1–30 Jupiter mass planet located inside the fixed cavity of a protoplanetary disc. The planet exchanges energy and angular momentum with the disc at resonant locations, and its eccentricity grows due to Lindblad resonances. We observe several phases of eccentricity growth where different eccentric Lindblad resonances dominate from 1:3 up to 3:5. The maximum values of eccentricity reached in our simulations are 0.65–0.75. We calculate the eccentricity growth rate for different planet masses and disc parameters and derive analytical dependencies on these parameters. We observe that the growth rate is proportional to both the planet’s mass and the characteristic disc mass for a wide range of parameters. In a separate set of simulations, we derived the width of the 1:3 Lindblad resonance.
Diagnostic value of 18F-fluorodeoxyglucose positron emission tomography and computed tomography for differentiating polymyalgia rheumatica and rheumatoid arthritis: Using classification and regression tree analysis
Authors: Ikuma Daisuke , Sawa Naoki , Yamanouchi Masayuki , Oba Yuki , Mizuno Hiroki , Suwabe Tatsuya , Hoshino Junichi , Ubara Yoshifumi
Published: June 2023

Objectives

Determining which sites were important to differentiate polymyalgia rheumatica (PMR) from rheumatoid arthritis (RA) using 18F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET-CT) is challenging.

Methods

Patients with PMR or RA who were undergoing PET-CT were recruited at two mutual-aid hospitals in Japan between 2009 and 2018. Classification and regression tree (CART) analyses were performed to identify FDG uptake patterns that differentiated PMR from RA.

Results

We enrolled 35 patients with PMR and 46 patients with RA. Univariate CART analysis showed that FDG uptake in the shoulder joints, spinous processes of the lumbar vertebrae, pubic symphysis, sternoclavicular joints, ischial tuberosities, greater trochanters, and hip joints differentiated PMR from RA. Multivariate CART analysis revealed that FDG uptake by at least one of the ischial tuberosities had the highest diagnostic value for distinguishing PMR from RA (sensitivity, 77.1%; specificity, 82.6%). We performed the same CART analysis to patients who had not undergone treatment (PMR, n = 28; RA, n = 9). Similar results were obtained, and sensitivity and specificity were increased (sensitivity, 89.3%; specificity, 88.8%).

Conclusions

In PET-CT, FDG uptake by at least one of the ischial tuberosities best discriminates between PMR and RA.
A Seat at the Table for Music Therapy: Perceptions of Music Therapy Within the Hospice Interdisciplinary Team
Authors: Fiore Jennifer , Ridgway Kaitlin , Buttermore Allison
Published: June 2023

Music therapy is a newer profession within hospice, with limited evidence of other disciplines’ perceptions of a music therapist’s role in hospice care. The purpose of this study was to examine if perception differences exist between music therapists and interdisciplinary team (IDT) members regarding how 25 job tasks related to the music therapist’s role within a clinical interdisciplinary hospice team. Two groups consisting of board-certified music therapists (MT-BC) and IDT members completed an online Qualtrics survey to rate how 25 job tasks were perceived to pertain to the music therapist’s role in hospice care. A two-way mixed ANOVA indicated the significant differences between the 2 groups for 13 of the 25 tasks, suggesting less understanding of an MT-BC’s role within a hospice IDT. For the 13 tasks perceived significantly different, a one-way ANOVA was run and indicated significant between discipline perceptual differences for nine of the 13 tasks. Qualitative statements indicated contracted and employed MT-BCs experienced similar perceived barriers of IDT colleagues lack of understanding music therapy and the MT-BC not being able to attend IDT or participate regularly. Overall, required IDT groups’ qualitative statements were positive, with the most common responses across disciplines indicating that MT-BCs elicited positive responses from patients and caregivers, provided a distraction from pain or agitation, and increased patients’ quality of life. The current study’s outcomes highlight the need for music therapists to provide more education to colleagues regarding a music therapist’s role in the hospice setting.
Music Therapy Knowledge, Interest, and Career Recommendations: A Survey of Music Educators
Authors: Springer D Gregory , Gooding Lori F
Published: June 2023

The purpose of this study was to examine high school music teachers’ knowledge of music therapy, interest in music therapy, and career recommendations for music therapy relative to other music careers. High school music teachers (N = 65) from one southeastern state completed a researcher-designed survey instrument designed to investigate these areas. Results indicated varied levels of knowledge about music therapy, although teachers who previously attended institutions that offered music therapy degree programs provided higher knowledge ratings than those who had not attended institutions with music therapy programs. Additionally, participants reported a relatively high interest in music therapy and a willingness to promote it as a career to their students. Participants reported that they were most likely to recommend music education as a career to their students, followed by music performance and music therapy. In response to open-ended questions, participants indicated that they believed personal characteristics were the most important qualities of prospective music therapists and that musical characteristics were the most important qualities of prospective music educators. They also expressed an interest in more information about music therapy, especially related to job characteristics. Implications of these findings and suggestions for future research are discussed.
Generalised interrelations among mutation rates drive the genomic compliance of Chargaff's second parity rule
Authors: Pflughaupt Patrick , Sahakyan Aleksandr B
Published: June 2023

Chargaff's second parity rule (PR-2), where the complementary base and k-mer contents are matching within the same strand of a double stranded DNA (dsDNA), is a phenomenon that invited many explanations. The strict compliance of nearly all nuclear dsDNA to PR-2 implies that the explanation should also be similarly adamant. In this work, we revisited the possibility of mutation rates driving PR-2 compliance. Starting from the assumption-free approach, we constructed kinetic equations for unconstrained simulations. The results were analysed for their PR-2 compliance by employing symbolic regression and machine learning techniques. We arrived to a generalised set of mutation rate interrelations in place in most species that allow for their full PR-2 compliance. Importantly, our constraints explain PR-2 in genomes out of the scope of the prior explanations based on the equilibration under mutation rates with simpler no-strand-bias constraints. We thus reinstate the role of mutation rates in PR-2 through its molecular core, now shown, under our formulation, to be tolerant to previously noted strand biases and incomplete compositional equilibration. We further investigate the time for any genome to reach PR-2, showing that it is generally earlier than the compositional equilibrium, and well within the age of life on Earth.
Reverse transcriptases prime DNA synthesis
Authors: Zabrady Matej , Zabrady Katerina , Li Arthur W H , Doherty Aidan J
Published: June 2023

The discovery of reverse transcriptases (RTs) challenged the central dogma by establishing that genetic information can also flow from RNA to DNA. Although they act as DNA polymerases, RTs are distantly related to replicases that also possess de novo primase activity. Here we identify that CRISPR associated RTs (CARTs) directly prime DNA synthesis on both RNA and DNA. We demonstrate that RT-dependent priming is utilized by some CRISPR-Cas complexes to synthesise new spacers and integrate these into CRISPR arrays. Expanding our analyses, we show that primer synthesis activity is conserved in representatives of other major RT classes, including group II intron RT, telomerase and retroviruses. Together, these findings establish a conserved innate ability of RTs to catalyse de novo DNA primer synthesis, independently of accessory domains or alternative priming mechanisms, which likely plays important roles in a wide variety of biological pathways.
Insights into a viral motor: the structure of the HK97 packaging termination assembly
Authors: Hawkins Dorothy E D P , Bayfield Oliver W , Fung Herman K H , Grba Daniel N , Huet Alexis , Conway James F , Antson Alfred A
Published: June 2023

Double-stranded DNA viruses utilise machinery, made of terminase proteins, to package viral DNA into the capsid. For cos bacteriophage, a defined signal, recognised by small terminase, flanks each genome unit. Here we present the first structural data for a cos virus DNA packaging motor, assembled from the bacteriophage HK97 terminase proteins, procapsids encompassing the portal protein, and DNA containing a cos site. The cryo-EM structure is consistent with the packaging termination state adopted after DNA cleavage, with DNA density within the large terminase assembly ending abruptly at the portal protein entrance. Retention of the large terminase complex after cleavage of the short DNA substrate suggests that motor dissociation from the capsid requires headful pressure, in common with pac viruses. Interestingly, the clip domain of the 12-subunit portal protein does not adhere to C12 symmetry, indicating asymmetry induced by binding of the large terminase/DNA. The motor assembly is also highly asymmetric, showing a ring of 5 large terminase monomers, tilted against the portal. Variable degrees of extension between N- and C-terminal domains of individual subunits suggest a mechanism of DNA translocation driven by inter-domain contraction and relaxation.
Interplay of endonucleolytic and exonucleolytic processing in the 3′-end formation of a mitochondrial nad2 RNA precursor in Arabidopsis
Authors: Wang Chuande , Quadrado Martine , Mireau Hakim
Published: June 2023

Initiation and termination of plant mitochondrial transcription are poorly controlled steps. Precursor transcripts are thus often longer than necessary, and 3′-end processing as well as control of RNA stability are essential to produce mature mRNAs in plant mitochondria. Plant mitochondrial 3′ ends are determined by 3′-to-5′ exonucleolytic trimming until the progression of mitochondrial exonucleases along transcripts is stopped by stable RNA structures or RNA binding proteins. In this analysis, we investigated the function of the endonucleolytic mitochondrial stability factor 1 (EMS1) pentatricopeptide repeat (PPR) protein and showed that it is essential for the production and the stabilization of the mature form of the nad2 exons 1–2 precursor transcript, whose 3′ end corresponds to the 5′ half of the nad2 trans-intron 2. The accumulation of an extended rather than a truncated form of this transcript in ems1 mutant plants suggests that the role of EMS1 in 3′ end formation is not strictly limited to blocking the passage of 3′-5′ exonucleolytic activity, but that 3′ end formation of the nad2 exons 1–2 transcript involves an EMS1-dependent endonucleolytic cleavage. This study demonstrates that the formation of the 3′ end of mitochondrial transcripts may involve an interplay of endonucleolytic and exonucleolytic processing mediated by PPR proteins.
Rarely acquired type II-A CRISPR-Cas spacers mediate anti-viral immunity through the targeting of a non-canonical PAM sequence
Authors: Kenney Claire T , Marraffini Luciano A
Published: June 2023

The Streptococcus pyogenes type II-A CRISPR-Cas systems provides adaptive immunity through the acquisition of short DNA sequences from invading viral genomes, called spacers. Spacers are transcribed into short RNA guides that match regions of the viral genome followed by a conserved NGG DNA motif, known as the PAM. These RNA guides, in turn, are used by the Cas9 nuclease to find and destroy complementary DNA targets within the viral genome. While most of the spacers present in bacterial populations that survive phage infection target protospacers flanked by NGG sequences, there is a small fraction that target non-canonical PAMs. Whether these spacers originate through accidental acquisition of phage sequences and/or provide efficient defense is unknown. Here we found that many of them match phage target regions flanked by an NAGG PAM. Despite being scarcely present in bacterial populations, NAGG spacers provide substantial immunity in vivo and generate RNA guides that support robust DNA cleavage by Cas9 in vitro; with both activities comparable to spacers that target sequences followed by the canonical AGG PAM. In contrast, acquisition experiments showed that NAGG spacers are acquired at very low frequencies. We therefore conclude that discrimination against these sequences occurs during immunization of the host. Our results reveal unexpected differences in PAM recognition during the spacer acquisition and targeting stages of the type II-A CRISPR-Cas immune response.
Dual chemical labeling enables nucleotide-resolution mapping of DNA abasic sites and common alkylation damage in human mitochondrial DNA
Authors: Liu Chaoxing , Le Brandon H , Xu Wenyan , Yang Ching-Hsin , Chen Yu Hsuan , Zhao Linlin
Published: June 2023

Mitochondrial DNA (mtDNA) modifications play an emerging role in innate immunity and inflammatory diseases. Nonetheless, relatively little is known regarding the locations of mtDNA modifications. Such information is critically important for deciphering their roles in mtDNA instability, mtDNA-mediated immune and inflammatory responses, and mitochondrial disorders. The affinity probe-based enrichment of lesion-containing DNA represents a key strategy for sequencing DNA modifications. Existing methods are limited in the enrichment specificity of abasic (AP) sites, a prevalent DNA modification and repair intermediate. Herein, we devise a novel approach, termed dual chemical labeling-assisted sequencing (DCL-seq), for mapping AP sites. DCL-seq features two designer compounds for enriching and mapping AP sites specifically at single-nucleotide resolution. For proof of principle, we mapped AP sites in mtDNA from HeLa cells under different biological conditions. The resulting AP site maps coincide with mtDNA regions with low TFAM (mitochondrial transcription factor A) coverage and with potential G-quadruplex-forming sequences. In addition, we demonstrated the broader applicability of the method in sequencing other DNA modifications in mtDNA, such as N7-methyl-2′-deoxyguanosine and N3-methyl-2′-deoxyadenosine, when coupled with a lesion-specific repair enzyme. Together, DCL-seq holds the promise to sequence multiple DNA modifications in various biological samples.
Structural and biochemical characterization of Schlafen11 N-terminal domain
Authors: Hou Pengjiao , Hao Wei , Qin Bo , Li Mengyun , Zhao Rong , Cui Sheng
Published: June 2023

Schlafen11 (SLFN11) is one of the most studied Schlafen proteins that plays vital roles in cancer therapy and virus-host interactions. Herein, we determined the crystal structure of the Sus scrofa SLFN11 N-terminal domain (NTD) to 2.69 Å resolution. sSLFN11-NTD is a pincer-shaped molecule that shares an overall fold with other SLFN-NTDs but exhibits distinct biochemical characteristics. sSLFN11-NTD is a potent RNase cleaving type I and II tRNAs and rRNAs, and with preference to type II tRNAs. Consistent with the codon usage-based translation suppression activity of SLFN11, sSLFN11-NTD cleaves synonymous serine and leucine tRNAs with different efficiencies in vitro. Mutational analysis revealed key determinates of sSLFN11-NTD nucleolytic activity, including the Connection-loop, active site, and key residues essential for substrate recognition, among which E42 constrains sSLFN11-NTD RNase activity, and all nonconservative mutations of E42 stimulated RNase activities. sSLFN11 inhibited the translation of proteins with a low codon adaptation index in cells, which mainly dependent on the RNase activity of the NTD because E42A enhanced the inhibitory effect, but E209A abolished inhibition. Our findings provide structural characterization of an important SLFN11 protein and expand our understanding of the Schlafen family.
Pervasive effects of RNA degradation on Nanopore direct RNA sequencing
Authors: Prawer Yair D J , Gleeson Josie , De Paoli-Iseppi Ricardo , Clark Michael B
Published: June 2023

Oxford Nanopore direct RNA sequencing (DRS) is capable of sequencing complete RNA molecules and accurately measuring gene and isoform expression. However, as DRS is designed to profile intact RNA, expression quantification may be more heavily dependent upon RNA integrity than alternative RNA sequencing methodologies. It is currently unclear how RNA degradation impacts DRS or whether it can be corrected for. To assess the impact of RNA integrity on DRS, we performed a degradation time series using SH-SY5Y neuroblastoma cells. Our results demonstrate that degradation is a significant and pervasive factor that can bias DRS measurements, including a reduction in library complexity resulting in an overrepresentation of short genes and isoforms. Degradation also biases differential expression analyses; however, we find that explicit correction can almost fully recover meaningful biological signal. In addition, DRS provided less biased profiling of partially degraded samples than Nanopore PCR-cDNA sequencing. Overall, we find that samples with RNA integrity number (RIN) > 9.5 can be treated as undegraded and samples with RIN > 7 can be utilized for DRS with appropriate correction. These results establish the suitability of DRS for a wide range of samples, including partially degraded in vivo clinical and post-mortem samples, while limiting the confounding effect of degradation on expression quantification.
Spinal meningiomas
Authors: Hohenberger Christoph , Hau Peter , Schebesch Karl-Michael , Kölbl Oliver , Riemenschneider Markus J , Pohl Fabian , Proeschold Martin , Schmidt Nils Ole
Published: June 2023

Spinal meningiomas (SM) are lesions with a mostly favorable oncological and surgical prognosis and a low incidence of tumor recurrence. SM account for approximately 1.2–12.7% of all meningiomas and 25% of all spinal cord tumors. Typically, SM are located in the intradural extramedullary space. SM grow slowly and spread laterally into the subarachnoid space, stretching and sometimes incorporating the surrounding arachnoid but rarely the pia. Standard treatment is surgery with the primary aims of achieving complete tumor resection as well as improving and recovering neurologic function. Radiotherapy may be considered in case of tumor recurrence, for challenging surgical cases, and for patients with higher-grade lesions (World Health Organization grade 2 or 3); however, radiotherapy is mostly used as an adjuvant therapy for SM. New molecular and genetic profiling increases the understanding of SM and may uncover additional treatment options.
Metasurfaces: physics and applications in wireless communications
Authors: Ataloglou Vasileios G , Taravati Sajjad , Eleftheriades George V
Published: June 2023

The ever increasing number of wireless devices and systems has led to a crowded spectrum and increased the demand for versatile and multi-functional wireless apparatuses. Recently, metasurfaces have been explored as a prominent technological solution to the current paradigm of spectrum scarcity by opportunistically sharing the spectrum with various users. In general, metasurfaces are passive/dynamic, ultra-compact, multi-functional and programmable structures that are capable of both reciprocal and nonreciprocal signal-wave transmissions. The controllability and programmability of such metasurfaces are governed through DC bias and occasionally a radio-frequency modulation applied to the active components of the unit cells of the metasurface, e.g. diodes and transistors. This article overviews some of the recently proposed passive and dynamic metasurfaces and shows that metasurfaces can enhance the performance of wireless communication systems thanks to their unique physical features such as real-time signal coding, nonreciprocal-beam radiation, nonreciprocal beamsteering amplification and advanced pattern-coding multiple access communication.