bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing Methods for Surveying Partner Nation Medical Capabilities
Authors: Stone Alexandra , Regalbuto Eric , Wilson Ramey L
Published: January 2023

Introduction

Medical capability surveys provide information about how U.S. forces can coordinate with partner nations to leverage partners’ capabilities to deliver care to sick or injured U.S. service members. Rotating forces routinely conduct these surveys. Currently, medical capability surveys are conducted based on individual unit requirements and personnel expertise and stored locally on component-specific sites or individual computers. The lack of a systematic approach and a centralized survey depot may undermine the ability to access previous surveys, leading to redundant surveys and conflicting information, and may have critical implications for force health protection. Partner nation facilities could have capabilities that may be leveraged to care for U.S. service members when U.S. medical care is unavailable. A lack of understanding of medical capabilities at partner nation facilities may undermine the ability to plan missions that mitigate risks.

Materials and Methods

This paper presents the results of 12 semi-structured focus groups with representatives from the U.S. Africa Command Surgeon’s office, the U.S. Transportation Command Patient Movement Requirements Center-East, and 9 U.S. Africa Command service components, sub-unified commands, and force providers. The focus group discussions considered questions on the following four topics: (1) methods for conducting surveys, (2) guidance about how to conduct surveys, (3) nodes of care and ancillary services included in surveys, and (4) how medical capability surveys are used to inform medical planning. The team conducted thematic analysis to identify emergent themes and subthemes.

Results

The team identified five primary, overarching themes: (1) guidance for conducting medical capability surveys, (2) methods and tools for conducting surveys, (3) content and focus of medical capability surveys, (4) archiving and sharing surveys, and (5) uses of medical capability surveys.

Conclusions

Implementing guidance and standardized templates for conducting medical capability surveys could improve the accuracy and completeness of surveys. Templates would likely increase the likelihood that surveyors collect relevant information on key medical capabilities. Training, along with guidance and templates, would provide a common understanding of how to conduct surveys. The lack of a DoD Global Health Engagement collaborative depot for storing and sharing surveys may undermine the ability to access previous surveys to inform future surveys and, thereby, results in inefficiencies in how surveys are conducted. The DoD should consider establishing a collaborative depot for medical capability surveys along with guidance or requirements for uploading surveys. Guidance, templates, training, and a collaborative depot could improve the effectiveness and efficiency of medical planning and thereby increase mission readiness.
Policy Recommendations for Increasing the Use of Evidence-Based Psychotherapy for Posttraumatic Stress Disorder in the Military Health System
Authors: McLean Carmen P , Cook Jeffrey , Riggs David S , Peterson Alan L , Young-McCaughan Stacey , Haddock Christopher K , Rosen Craig S
Published: January 2023

Few service members with posttraumatic stress disorder (PTSD) receive evidence-based psychotherapy (EBP) in the military health system (MHS). Efforts to increase EBP implementation have focused on provider training but have not adequately addressed organizational barriers. Thus, although behavioral health providers are trained in EBPs, clinic-, facility-, and system-level barriers preclude widespread EBP implementation. Building on work examining barriers to EBP use for PTSD across eight military treatment facilities, we propose recommendations for increasing the implementation of EBPs for PTSD and improving the quality of behavioral health care in MHS outpatient behavioral health clinics. Increasing the use of EBPs for PTSD will require that their use is supported and prioritized through MHS policy. We recommend that psychotherapy appointments are scheduled at least once weekly, as clinically indicated, as this frequency of care is prerequisite for EBP delivery. We propose several recommendations designed to increase system capacity for weekly psychotherapy, including improved triaging of potential patients, incentivizing and supporting group psychotherapy, matching the modality (i.e., group vs. individual) and frequency of treatment to patients’ needs, and using behavioral health technicians as clinician extenders. Additional recommendations include providing ongoing support for EBP implementation (e.g., protected time to participate in EBP consultation) and matching patients to providers based on patient’s clinical needs and treatment preferences. The barriers to EBP implementation that these recommendations target are interrelated. Therefore, adopting multiple policy recommendations is likely necessary to yield a meaningful and sustained increase in the implementation of EBPs for PTSD in the MHS.
Geomagnetic storm forecasting from solar coronal holes
Authors: Nitti Simona , Podladchikova Tatiana , Hofmeister Stefan J , Veronig Astrid M , Verbanac Giuliana , Bandić Mario
Published: January 2023

Coronal holes (CHs) are the source of high-speed streams (HSSs) in the solar wind, whose interaction with the slow solar wind creates corotating interaction regions (CIRs) in the heliosphere. Whenever the CIRs hit the Earth, they can cause geomagnetic storms. We develop a method to predict the strength of CIR/HSS-driven geomagnetic storms directly from solar observations using the CH areas and associated magnetic field polarity. First, we build a data set comprising the properties of CHs on the Sun, the associated HSSs, CIRs, and orientation of the interplanetary magnetic field (IMF) at L1, and the strength of the associated geomagnetic storms by the geomagnetic indices Dst and Kp. Then, we predict the Dst and Kp indices using a Gaussian process model, which accounts for the annual variation of the orientation of Earth’s magnetic field axis. We demonstrate that the polarity of the IMF at L1 associated with CIRs is preserved in around 83 per cent of cases when compared to the polarity of their CH sources. Testing our model over the period 2010–2020, we obtained a correlation coefficient between the predicted and observed Dst index of R = 0.63/0.73, and Kp index of R = 0.65/0.67, for HSSs having a polarity towards/away from the Sun. These findings demonstrate the possibility of predicting CIR/HSS-driven geomagnetic storms directly from solar observations and extending the forecasting lead time up to several days, which is relevant for enhancing space weather predictions.
The contribution of magnetized galactic outflows to extragalactic Faraday rotation
Authors: Arámburo-García Andrés , Bondarenko Kyrylo , Boyarsky Alexey , Neronov Andrii , Scaife Anna , Sokolenko Anastasia
Published: January 2023

Galactic outflows driven by star formation and active galactic nuclei blow bubbles into their local environments, causing galactic magnetic fields to be carried into intergalactic space. We explore the redshift-dependent effect of these magnetized bubbles on the Faraday rotation measure (RM) of extragalactic radio sources. Using the IllustrisTNG cosmological simulations, we separate the contribution from magnetic bubbles from that of the volume-filling magnetic component expected to be due to the seed field originating in the early universe. We use this separation to extract the redshift dependence of each component and to compare IllustrisTNG model predictions with observation measurements of the NRAO VLA sky survey (NVSS). We find that magnetized bubbles provide a sizeable contribution to the extragalactic RM, with redshift-independent 〈|RM|〉 ≃ 13 rad/m2 for sources at redshifts z ≥ 2. This is close to the mean residual RM of 16 rad/m2 found from NVSS data in this redshift range. Using the IllustrisTNG simulations, we also evaluate a simple model for the contribution to residual RM from individual host galaxies and show that this contribution is negligible at high-redshift. While the contribution from magnetic bubbles in the IllustrisTNG model is currently compatible with observational measurements of residual RM, the next-generation RM sky surveys, which will be free from the wrapping uncertainty, have larger statistics and better sensitivity should be able to observe predicted flat contribution from magnetic bubbles at large redshifts. This should allow to experimentally probe magnetic bubbles and check models of galaxy feedback in cosmological simulations.
An environmental analysis of the fast transient AT2018cow and implications for its progenitor and late-time brightness
Authors: Sun Ning-Chen , Maund Justyn R , Shao Yali , Janiak Ida A
Published: January 2023

The nature of the newly discovered fast blue optical transients (FBOTs) is still puzzling astronomers. In this paper, we carry out a comprehensive analysis of the molecular gas, ionized gas, and stellar populations in the environment of the nearby FBOT AT2018cow based on ALMA, VLT/MUSE, and HST/WFC3 observations. A prominent molecular concentration of 6 (± 1) × 106 M⊙ is found in the vicinity of AT2018cow, which has given rise to two active star-forming complexes with ages of 4 ± 1 and ≲2.5 Myr, respectively. Each star-forming complex has a stellar mass of 3 × 105 M⊙, and has photoionized a giant H ii region with Hα luminosity even comparable to that of the 30 Dor mini-starburst region. AT2018cow is spatially coincident with one of the star-forming complexes; however, it is most likely to reside in its foreground since it has a much smaller extinction than the complex. Its progenitor could have been formed in a different star-forming event, and the non-detection of the associated stellar population constrains the progenitor’s age to be ≳10 Myr and initial mass to be ≲20 M⊙. We further find the late-time brightness of AT2018cow is unlikely to be a stellar object. Its brightness has slightly declined from 2 to 4 yr after explosion and is most likely to originate from AT2018cow itself due to some powering mechanism still working at such late times.
Star formation at the smallest scales: a JWST study of the clump populations in SMACS0723
Authors: Claeyssens Adélaïde , Adamo Angela , Richard Johan , Mahler Guillaume , Messa Matteo , Dessauges-Zavadsky Miroslava
Published: January 2023

We present the clump populations detected in 18 lensed galaxies at redshifts 1--8.5 within the lensing cluster field SMACS0723. The recent JWST Early Release Observations of this poorly known region of the sky have revealed numerous point-like sources within and surrounding their host galaxies, undetected in the shallower Hubble Space Telescope images. We use JWST multi-and photometry and the lensing model of this galaxy cluster to estimate the intrinsic sizes and magnitudes of the stellar clumps. We derive optical restframe effective radii from <10 to hundreds pc and masses ranging from ∼105 to 109 M ⊙, overlapping with massive star clusters in the local universe. Clump ages range from 1 Myr to 1 Gyr. We compare the crossing time to the age of the clumps and determine that between 45 and 60  per cent of the detected clumps are consistent with being gravitationally bound. On average, the dearth of Gyr old clumps suggests that the dissolution time scales are shorter than 1 Gyr. We see a significant increase in the luminosity (mass) surface density of the clumps with redshift. Clumps in reionization era galaxies have stellar densities higher than star clusters in the local universe. We zoom in into single galaxies at redshift <6 and find for two galaxies, the Sparkler and the Firework, that their star clusters/clumps show distinctive colour distributions and location surrounding their host galaxy that are compatible with being accredited or formed during merger events. The ages of some of the compact clusters are between 1 and 4 Gyr, e.g. globular cluster precursors formed around 9--12 Gyr ago. Our study, conducted on a small sample of galaxies, shows the potential of JWST observations for understanding the conditions under which star clusters form in rapidly evolving galaxies.
The rotation rate of solar active and ephemeral regions – II. Temporal variations of the rotation rates
Authors: Kutsenko Alexander S , Abramenko Valentina I , Litvishko Daria V
Published: January 2023

Systematic studies of the rotation rate of sunspot groups using white light images yield controversial results on the variations of the rotation rate: sunspot groups were found to either accelerate or decelerate systematically. This disagreement might be related to shortcomings of the method used to probe the rotation rate of sunspot groups. In contrast to previous works, in this study we use magnetic field maps to analyse the variations of the rotation rate of active regions. We found that an active region may exhibit either acceleration or deceleration during the emergence, while the rotation rate remains almost unchanged during decay. Hence, we suppose that there is no systematic geometrical inclination to the radial direction of the apex of the subsurface magnetic flux loop forming an active region. A thorough comparison of the rotation rate of unipolar and bi/multipolar active regions revealed no significant changes in the rotation rate of decaying active regions. In contrast to previous works, we presume the rotation rate to remain constant (within the expected uncertainties) during the evolution of an active region after emergence.
Dissecting the active galactic nucleus in Circinus – IV. MUSE-NFM observations unveil a tuning-fork ionized outflow morphology
Authors: Kakkad D , Stalevski M , Kishimoto M , Knežević S , Asmus D , Vogt F P A
Published: January 2023

We present the ionized gas outflow morphology in the Circinus galaxy using the narrow-field mode (NFM) of the Multi Unit Spectroscopic Explorer (MUSE) instrument onboard the Very Large Telescope (VLT). The NFM observations provide a spatial resolution of ∼0.1 arcsec, corresponding to a physical scale of ∼2 pc, one of the highest spatial resolution achievable using ground-based adaptive optics-assisted observations in the optical wavelengths. The MUSE observations reveal a collimated clumpy outflow profile originating near the active galactic nucleus (AGN) location and extending up to 1.5 arcsec (∼30 pc) in the north-west direction. The collimated structure then fragments into two filaments, giving the entire outflowing gas a ‘tuning-fork’ morphology. These structures remain undetected in the lower spatial resolution MUSE wide-field mode data. We explain the origin of this tuning-fork structure to the interaction of the outflow with a dense clump in the interstellar medium (ISM) as the outflow propagates outwards. The origin of the collimated structure itself could be from jet–ISM interactions on small scales. These observations also provide evidence to the origin of the ionized gas filaments previously observed in the Circinus galaxy out to kiloparsec scales. We find instantaneous and time-averaged mass outflow rates of 10−2 and 10−4 M⊙ yr−1, respectively. Based on the star formation rate in the Circinus galaxy reported in the literature, the observed ionized outflows are not expected to regulate star formation within the ∼100 pc scales probed by the NFM data.
A comparison of numerical methods for computing the reionization of intergalactic hydrogen and helium by a central radiating source
Authors: Leong Ka-Hou , Meiksin Avery , Lai Althea , To K H
Published: January 2023

We compare numerical methods for solving the radiative transfer equation in the context of the photoionization of intergalactic gaseous hydrogen and helium by a central radiating source. Direct integration of the radiative transfer equation and solutions using photon packets are examined, both for solutions to the time-dependent radiative transfer equation and in the infinite-speed-of-light approximation. The photon packet schemes are found to be more generally computationally efficient than a direct integration scheme. While all codes accurately describe the growth rate of hydrogen and helium ionization zones, it is shown that a fully time-dependent method is required to capture the gas temperature and ionization structure in the near zone of a source when an ionization front expands at a speed close to the speed of light. Applied to quasi-stellar objects in the Epoch of Reionization (EoR), temperature differences as high as 5 × 104 K result in the near zone for solutions of the time-dependent radiative transfer equation compared with solutions in the infinite-speed-of-light approximation. Smaller temperature differences are found following the nearly full photoionization of helium in gas in which the hydrogen was already ionized and the helium was singly ionized. Variations found in the temperature and ionization structure far from the source, where the gas is predominantly neutral, may affect some predictions for 21-cm EoR experiments.
Star formation histories of UV-luminous galaxies at z ≃ 6.8: implications for stellar mass assembly at early cosmic times
Authors: Whitler Lily , Stark Daniel P , Endsley Ryan , Leja Joel , Charlot Stéphane , Chevallard Jacopo
Published: January 2023

The variety of star formation histories (SFHs) of z ≳ 6 galaxies provides important insights into early star formation, but has been difficult to systematically quantify. Some observations suggest that many z ∼ 6–9 galaxies are dominated by ≳200 Myr stellar populations, implying significant star formation at z ≳ 9, while others find that most reionization era galaxies are ≲10 Myr, consistent with little z ≳ 9 star formation. Here, we quantify the distribution of ages of UV-bright ($-22.5\lesssim M_{\rm \small UV}\lesssim -21$) galaxies colour-selected to lie at z ≃ 6.6–6.9, an ideal redshift range to systematically study the SFHs of reionization era galaxies with ground-based observatories and Spitzer. We infer galaxy properties with two SED modelling codes and compare results, finding that stellar masses are largely insensitive to the model, but the inferred ages can vary by an order of magnitude. We infer a distribution of ages assuming a simple, parametric SFH model, finding a median age of ∼30–70 Myr depending on SED model. We quantify the fractions of ≤10 and ≥250 Myr galaxies, finding that these systems comprise ∼15–30 per cent and ∼20–25 per cent of the population, respectively. With a flexible SFH model, the shapes of the SFHs are consistent with those implied by the simple model (e.g. young galaxies have rapidly rising SFHs). However, stellar masses can differ significantly, with those of young systems sometimes being more than an order of magnitude larger with the flexible SFH. We quantify the implications of these results for z ≳ 9 stellar mass assembly and discuss improvements expected from JWST.
Quasi-periodic behaviour in the radio and γ-ray light curves of blazar PKS 1510–089
Authors: Li Xiao-Pan , Cai Yan , Yang Hai-Yan , Lähteenmäki Anne , Tornikoski Merja , Tammi Joni , Suutarinen Sofia , Yang Hai-Tao , Luo Yu-Hui , Wang Li-Sha
Published: January 2023

We explore the possible quasi-periodic oscillations (QPOs) of the blazar PKS 1510–089, utilizing the ∼38-year Metsähovi flux density observations at 37 GHz and over ten-year Fermi-LAT observations in the 0.1–300 GeV energy range. Both the flux distributions of the radio and γ-ray light curves suggest a log-normal distribution, and power spectral densities (PSDs) of both light curves can be well represented by a bending power-law model. Comparing the results from the Weighted Wavelet Z-transform and Lomb-Scargle Periodogram approaches, a quasi period of 1330 ± 55 days at a 99.80% (>3σ) significance against the red noise background is observed in the radio light curve, whereas no similar modulation is seen in the γ-ray light curve. We briefly discuss the research actuality of blazar QPO phenomena and explain the observed radio QPO as the result of Keplerian motion in a supermassive binary black hole system and periodic modulation induced by the Lense-Thirring precession of the innermost portions of the accretion disk.
A study of convective core overshooting as a function of stellar mass based on two-dimensional hydrodynamical simulations
Authors: Baraffe I , Clarke J , Morison A , Vlaykov D G , Constantino T , Goffrey T , Guillet T , Le Saux A , Pratt J
Published: January 2023

We perform two-dimensional (2D) numerical simulations of core convection for zero-age main-sequence stars covering a mass range from 3 to 20 M⊙. The simulations are performed with the fully compressible time-implicit code music. We study the efficiency of overshooting, which describes the ballistic process of convective flows crossing a convective boundary, as a function of stellar mass and luminosity. We also study the impact of artificially increasing the stellar luminosity for 3 M⊙ models. The simulations cover hundreds to thousands of convective turnover time-scales. Applying the framework of extreme plume events previously developed for convective envelopes, we derive overshooting lengths as a function of stellar masses. We find that the overshooting distance (dov) scales with the stellar luminosity (L) and the convective core radius (rconv). We derive a scaling law $d_{\rm ov} \propto L^{1/3} r_{\rm conv}^{1/2}$, which is implemented in a one-dimensional stellar evolution code and the resulting stellar models are compared to observations. The scaling predicts values for the overshooting distance that significantly increase with stellar mass, in qualitative agreement with observations. Quantitatively, however, the predicted values are underestimated for masses ≳10 M⊙. Our 2D simulations show the formation of a nearly adiabatic layer just above the Schwarzschild boundary of the convective core, as exhibited in recent three-dimensional simulations of convection. The most luminous models show a growth in size with time of the nearly adiabatic layer. This growth seems to slow down as the upper edge of the nearly adiabatic layer gets closer to the maximum overshooting length and as the simulation time exceeds the typical thermal diffusive time-scale in the overshooting layer.
Dynamics of dwarf galaxies in f(R) gravity
Authors: de Martino Ivan , Diaferio Antonaldo , Ostorero Luisa
Published: January 2023

We use the kinematic data of the stars in eight dwarf spheroidal galaxies to assess whether f(R) gravity can fit the observed profiles of the line-of-sight velocity dispersion of these systems without resorting to dark matter. Our model assumes that each galaxy is spherically symmetric and has a constant velocity anisotropy parameter β and constant mass-to-light ratio consistent with stellar population synthesis models. We solve the spherical Jeans equation that includes the Yukawa-like gravitational potential appearing in the weak field limit of f(R) gravity, and a Plummer density profile for the stellar distribution. The f(R) velocity dispersion profiles depends on two parameters: the scale length ξ−1, below which the Yukawa term is negligible, and the boost of the gravitational field δ > −1. δ and ξ are not universal parameters, but their variation within the same class of objects is expected to be limited. The f(R) velocity dispersion profiles fit the data with a value $\xi ^{-1}= 1.2^{+18.6}_{-0.9}$ Mpc for the entire galaxy sample. On the contrary, the values of δ show a bimodal distribution that picks at $\overline{\delta }=-0.986\pm 0.002$ and $\overline{\delta }=-0.92\pm 0.01$. These two values disagree at 6σ and suggest a severe tension for f(R) gravity. It remains to be seen whether an improved model of the dwarf galaxies or additional constraints provided by the proper motions of stars measured by future astrometric space missions can return consistent δ’s for the entire sample and remove this tension.
ATOMS: ALMA three-millimeter observations of massive star-forming regions – XIII. Ongoing triggered star formation within clump-fed scenario found in the massive (∼1500 M⨀) clump
Authors: Zhang Siju , Wang Ke , Liu Tie , Zavagno Annie , Juvela Mika , Liu Hongli , Tej Anandmayee , Stutz Amelia M , Li Shanghuo , Bronfman Leonardo , Zhang Qizhou , Goldsmith Paul F , Lee Chang Won , Vázquez-Semadeni Enrique , Tatematsu Ken’ichi , Jiao Wenyu , Xu Fengwei , Wang Chao , Zhou Jian-Wen
Published: January 2023

Whether ionization feedback triggers the formation of massive stars is highly debated. Using ALMA 3-mm observations with a spatial resolution of ∼0.05 pc and a mass sensitivity of 1.1 $\rm M_\odot$ per beam at 20 K, we investigate the star formation and gas flow structures within the ionizing feedback-driven structure, a clump-scale massive (≳ 1500 $\rm M_\odot$) bright-rimmed cloud (BRC) associated with IRAS 18290–0924. This BRC is bound only if external compression from ionized gas is considered. A small-scale (≲ 1 pc) age sequence along the direction of ionizing radiation is revealed for the embedded cores and protostars, which suggests triggered star formation via radiation-driven implosion (RDI). Furthermore, filamentary gas structures converge towards the cores located in the BRC’s centre, indicating that these filaments are fueling mass towards cores. The local core-scale mass infall rate derived from H13CO+ J = 1 − 0 blue profile is of the same order of magnitude as the filamentary mass inflow rate, approximately 1 $\rm M_\odot$ kyr−1. A photodissociation region (PDR) covering the irradiated clump surface is detected in several molecules, such as CCH, HCO+, and CS whereas the spatial distribution stratification of these molecules is indistinct. CCH spectra of the PDR possibly indicate a photoevaporation flow leaving the clump surface with a projected velocity of ∼2 km s−1. Our new observations show that RDI accompanied by a clump-fed process is operating in this massive BRC. Whether this combined process works in other massive BRCs is worth exploring with dedicated surveys.
The orbital kinematics of η Carinae over three periastra with a possible detection of the elusive secondary’s motion
Authors: Strawn Emily , Richardson Noel D , Moffat Anthony F J , Ibrahim Nour , Lane Alexis , Pickett Connor , Chené André-Nicolas , Corcoran Michael F , Damineli Augusto , Gull Theodore R , Hillier D John , Morris Patrick , Pablo Herbert , Thomas Joshua D , Stevens Ian R , Teodoro Mairan , Weigelt Gerd
Published: January 2023

The binary η Carinae is the closest example of a very massive star, which may have formed through a merger during its Great Eruption in the mid-19th century. We aimed to confirm and improve the kinematics using a spectroscopic data set taken with the Cerro Tololo Inter-American Observatory 1.5-m telescope over the time period of 2008–2020, covering three periastron passages of the highly eccentric orbit. We measure line variability of H α and H β, where the radial velocity and orbital kinematics of the primary star were measured from the H β emission line using a bisector method. At phases away from periastron, we observed the He ii 4686 emission moving opposite the primary star, consistent with a possible Wolf–Rayet companion, although with a seemingly narrow emission line. This could represent the first detection of emission from the companion.
Dynamics of a relativistic jet through magnetized media
Authors: García-García Leonardo , López-Cámara Diego , Lazzati Davide
Published: January 2023

The merger of two neutron stars (NSs) produces the emission of gravitational waves, the formation of a compact object surrounded by a dense and magnetized environment. If the binary undergoes delayed collapse a collimated and relativistic jet, which will eventually produce a short gamma-ray burst (SGRB), may be launched. The interaction of the jet with the environment has been shown to play a major role in shaping the structure of the outflow that eventually powers the gamma-ray emission. In this paper, we present a set of 2.5D RMHD simulations that follow the evolution of a relativistic non-magnetized jet through a medium with different magnetization levels, as produced after the merger of two NSs. We find that the predominant consequence of a magnetized ambient medium is that of suppressing instabilities within the jet and preventing the formation of a series of collimation shocks. One implication of this is that internal shocks lose efficiency, causing bursts with low-luminosity prompt emission. On the other hand, the jet-head velocity and the induced magnetization within the jet are fairly independent of the magnetization of the ambient medium. Future numerical studies with a larger domain are necessary to obtain light curves and spectra in order to better understand the role of magnetized media.
Noise-Net: determining physical properties of H iiregions reflecting observational uncertainties
Authors: Kang Da Eun , Klessen Ralf S , Ksoll Victor F , Ardizzone Lynton , Koethe Ullrich , Glover Simon C O
Published: January 2023

Stellar feedback, the energetic interaction between young stars and their birthplace, plays an important role in the star formation history of the Universe and the evolution of the interstellar medium. Correctly interpreting the observations of star-forming regions is essential to understand stellar feedback, but it is a non-trivial task due to the complexity of the feedback processes and degeneracy in observations. In our recent paper, we introduced a conditional invertible neural network (cINN) that predicts seven physical properties of star-forming regions from the luminosity of 12 optical emission lines as a novel method to analyse degenerate observations. We demonstrated that our network, trained on synthetic star-forming region models produced by the warpfield-emission predictor (warpfield-emp), could predict physical properties accurately and precisely. In this paper, we present a new updated version of the cINN that takes into account the observational uncertainties during network training. Our new network named Noise-Net reflects the influence of the uncertainty on the parameter prediction by using both emission-line luminosity and corresponding uncertainties as the necessary input information of the network. We examine the performance of the Noise-Net as a function of the uncertainty and compare it with the previous version of the cINN, which does not learn uncertainties during the training. We confirm that the Noise-Net outperforms the previous network for the typical observational uncertainty range and maintains high accuracy even when subject to large uncertainties.
AGNs in post-mergers from the ultraviolet near infrared optical northern survey
Authors: Bickley Robert W , Ellison Sara L , Patton David R , Wilkinson Scott
Published: January 2023

The kinematic disturbances associated with major galaxy mergers are known to produce gas inflows, which in turn may trigger accretion onto the supermassive black holes (SMBH) of the participant galaxies. While this effect has been studied in galaxy pairs, the frequency of active galactic nuclei (AGNs) in fully coalesced post-merger systems is poorly constrained due to the limited size or impurity of extant post-merger samples. Previously, we combined convolutional neural network (CNN) predictions with visual classifications to identify a highly pure sample of 699 post-mergers in deep r-band imaging. In the work presented here, we quantify the frequency of AGNs in this sample using three metrics: optical emission lines, mid-infrared (mid-IR) colour, and radio detection of low-excitation radio galaxies (LERGs). We also compare the frequency of AGNs in post-mergers to that in a sample of spectroscopically identified galaxy pairs. We find that AGNs identified by narrow-line optical emission and mid-IR colour have an increased incidence rate in post-mergers, with excesses of ~4 over mass- and redshift-matched controls. The optical and mid-IR AGN excesses in post-mergers exceed the values found for galaxy pairs, indicating that AGN activity in mergers peaks after coalescence. Conversely, we recover no significant excess of LERGs in post-mergers or pairs. Finally, we find that the [O iii] luminosity (a proxy for SMBH accretion rate) in post-mergers that host an optical AGN is ~0.3 dex higher on average than in non-interacting galaxies with an optical AGN, suggesting that mergers generate higher accretion rates than secular triggering mechanisms.
The smallest planetary drivers of white dwarf pollution
Authors: Veras Dimitri , Rosengren Aaron J
Published: January 2023

Many potential mechanisms for delivering planetary debris to within a few Roche radii of white dwarfs rely on gravitational scattering events that feature perturbers which are giant planets or terrestrial planets. However, the population of these planets orbiting white dwarfs is still unknown, and for a substantial fraction of white dwarfs the largest planetary survivors of stellar evolution may be sub-terrestrial mass minor planets. Here, we attempt to identify the smallest mass perturbers that could pollute white dwarfs. Through computationally expensive numerical simulations of both unstable and stable configurations of minor planets, we find that this critical lower bound equals approximately one Luna mass (1M☾ ≈ 10-1  M♂ ≈ 10-2  M⊕ ≈ 102  MCeres). Further, we find that as this mass limit is approached from above, the typical cooling age at which white dwarf pollution occurs increases. Consequently, there is a two order-of-magnitude range of perturber masses between Earth and its moon that has remained largely unexplored in white dwarf pollution studies, despite the potential formation of thousands of such Luna-sized objects in these systems.
Tidal capture of stars by supermassive black holes: implications for periodic nuclear transients and quasi-periodic eruptions
Authors: Cufari M , Nixon C J , Coughlin Eric R
Published: January 2023

Stars that plunge into the centre of a galaxy are tidally perturbed by a supermassive black hole (SMBH), with closer encounters resulting in larger perturbations. Exciting these tides comes at the expense of the star’s orbital energy, which leads to the naive conclusion that a smaller pericentre (i.e. a closer encounter between the star and SMBH) always yields a more tightly bound star to the SMBH. However, once the pericentre distance is small enough that the star is partially disrupted, morphological asymmetries in the mass lost by the star can yield an increase in the orbital energy of the surviving core, resulting in its ejection – not capture – by the SMBH. Using smoothed particle hydrodynamics simulations, we show that the combination of these two effects – tidal excitation and asymmetric mass-loss – results in a maximum amount of energy lost through tides of $\sim 2.5{{\ \rm per\ cent}}$ of the binding energy of the star, which is significantly smaller than the theoretical maximum of the total stellar binding energy. This result implies that stars that are repeatedly partially disrupted by SMBHs many (≳10) times on short-period orbits (≲few years), as has been invoked to explain the periodic nuclear transient ASASSN-14ko and quasi-periodic eruptions, must be bound to the SMBH through a mechanism other than tidal capture, such as a dynamical exchange (i.e. Hills capture).
Reconstruction of Plastid Proteomes of Apicomplexans and Close Relatives Reveals the Major Evolutionary Outcomes of Cryptic Plastids
Authors: Mathur Varsha , Salomaki Eric D , Wakeman Kevin C , Na Ina , Kwong Waldan K , Kolisko Martin , Keeling Patrick J
Published: January 2023

Apicomplexans and related lineages comprise many obligate symbionts of animals; some of which cause notorious diseases such as malaria. They evolved from photosynthetic ancestors and transitioned into a symbiotic lifestyle several times, giving rise to species with diverse non-photosynthetic plastids. Here, we sought to reconstruct the evolution of the cryptic plastids in the apicomplexans, chrompodellids, and squirmids (ACS clade) by generating five new single-cell transcriptomes from understudied gregarine lineages, constructing a robust phylogenomic tree incorporating all ACS clade sequencing datasets available, and using these to examine in detail, the evolutionary distribution of all 162 proteins recently shown to be in the apicoplast by spatial proteomics in Toxoplasma. This expanded homology-based reconstruction of plastid proteins found in the ACS clade confirms earlier work showing convergence in the overall metabolic pathways retained once photosynthesis is lost, but also reveals differences in the degrees of plastid reduction in specific lineages. We show that the loss of the plastid genome is common and unexpectedly find many lineage- and species-specific plastid proteins, suggesting the presence of evolutionary innovations and neofunctionalizations that may confer new functional and metabolic capabilities that are yet to be discovered in these enigmatic organelles.
Canalization of Phenotypes—When the Transcriptome is Constantly but Weakly Perturbed
Authors: Lu Guang-An , Zhang Jinning , Zhao Yixin , Chen Qingjian , Lin Pei , Tang Tian , Tang Zhixiong , Wen Haijun , Liufu Zhongqi , Wu Chung-I
Published: January 2023

Recent studies have increasingly pointed to microRNAs (miRNAs) as the agent of gene regulatory network (GRN) stabilization as well as developmental canalization against constant but small environmental perturbations. To analyze mild perturbations, we construct a Dicer-1 knockdown line (dcr-1 KD) in Drosophila that modestly reduces all miRNAs by, on average, ∼20%. The defining characteristic of stabilizers is that, when their capacity is compromised, GRNs do not change their short-term behaviors. Indeed, even with such broad reductions across all miRNAs, the changes in the transcriptome are very modest during development in stable environment. By comparison, broad knockdowns of other regulatory genes (esp. transcription factors) by the same method should lead to drastic changes in the GRNs. The consequence of destabilization may thus be in long-term development as postulated by the theory of canalization. Flies with modest miRNA reductions may gradually deviate from the developmental norm, resulting in late-stage failures such as shortened longevity. In the optimal culture condition, the survival to adulthood is indeed normal in the dcr-1 KD line but, importantly, adult longevity is reduced by ∼90%. When flies are stressed by high temperature, dcr-1 KD induces lethality earlier in late pupation and, as the perturbations are shifted earlier, the affected stages are shifted correspondingly. Hence, in late stages of development with deviations piling up, GRN would be increasingly in need of stabilization. In conclusion, miRNAs appear to be a solution to weak but constant environmental perturbations.
Comprehensive molecular analysis identifies eight novel variants in XY females with disorders of sex development
Authors: Kulkarni Vinayak , Chellasamy Selvaa Kumar , Dhangar Somprakash , Ghatanatti Jagdeeshwar , Vundinti Babu Rao
Published: January 2023

Disorders of sex development (DSD) are a group of clinical conditions with variable presentation and genetic background. Females with or without development of secondary sexual characters and presenting with primary amenorrhea (PA) and a 46,XY karyotype are one of the classified groups in DSD. In this study, we aimed to determine the genetic mutations in 25 females with PA and a 46,XY karyotype to show correlations with their phenotypes. Routine Sanger sequencing with candidate genes like SRY, AR, SRD5A2, and SF1, which are mainly responsible for 46,XY DSD in adolescent females, was performed. In a cohort of 25 patients of PA with 46,XY DSD, where routine Sanger sequencing failed to detect the mutations, next-generation sequencing of a targeted gene panel with 81 genes was used for the molecular diagnosis. The targeted sequencing identified a total of 21 mutations including 8 novel variants in 20 out of 25 patients with DSD. The most frequently identified mutations in our series were in AR (36%), followed by SRD5A2 (20%), SF1 (12%), DHX37 (4%), HSD17B3 (4%), and DMRT2 (4%). We could not find any mutation in the DSD-related genes in five (20%) patients due to complex molecular mechanisms in 46,XY DSD, highlighting the possibility of new DSD genes which are yet to be discovered in these disorders. In conclusion, genetic testing, including cytogenetics and molecular genetics, is important for the diagnosis and management of 46,XY DSD cases.
Methods for analyzing the coordination and aggregation of metal–amyloid-β
Authors: Park Seongmin , Na Chanju , Han Jiyeon , Lim Mi Hee
Published: January 2023

The misfolding and aggregation of amyloid-β (Aβ) peptides are histopathological features found in the brains of Alzheimer's disease (AD). To discover effective therapeutics for AD, numerous efforts have been made to control the aggregation of Aβ species and their interactions with other pathological factors, including metal ions. Metal ions, such as Cu(II) and Zn(II), can bind to Aβ peptides forming metal-bound Aβ (metal–Aβ) complexes and, subsequently, alter their aggregation pathways. In particular, redox-active metal ions bound to Aβ species can produce reactive oxygen species leading to oxidative stress. In this review, we briefly illustrate some experimental approaches for characterizing the coordination and aggregation properties of metal–Aβ complexes.
A novel active transposon creates allelic variation through altered translation rate to influence protein abundance
Authors: Chen Guo , Wang Ruilin , Jiang Yizhe , Dong Xiaoxiao , Xu Jing , Xu Qiang , Kan Qiuxin , Luo Zhixiang , Springer Nathan M , Li Qing
Published: January 2023

Protein translation is tightly and precisely controlled by multiple mechanisms including upstream open reading frames (uORFs), but the origins of uORFs and their role in maize are largely unexplored. In this study, an active transposition event was identified during the propagation of maize inbred line B73. The transposon, which was named BTA for ‘B73 active transposable element hAT’, creates a novel dosage-dependent hypomorphic allele of the hexose transporter gene ZmSWEET4c through insertion within the coding sequence in the first exon, and results in reduced kernel size. The BTA insertion does not affect transcript abundance but reduces protein abundance of ZmSWEET4c, probably through the introduction of a uORF. Furthermore, the introduction of BTA sequence in the exon of other genes can regulate translation efficiency without affecting their mRNA levels. A transposon capture assay revealed 79 novel insertions for BTA and BTA-like elements. These insertion sites have typical euchromatin features, including low levels of DNA methylation and high levels of H3K27ac. A putative autonomous element that mobilizes BTA and BTA-like elements was identified. Together, our results suggest a transposon-based origin of uORFs and document a new role for transposable elements to influence protein abundance and phenotypic diversity by affecting the translation rate.
Structure-based investigations of the NAD+-II riboswitch
Authors: Xu Xiaochen , Egger Michaela , Li Chunyan , Chen Hao , Micura Ronald , Ren Aiming
Published: January 2023

Riboswitches are conserved non-coding domains in bacterial mRNA with gene regulation function that are essential for maintaining enzyme co-factor metabolism. Recently, the pnuC RNA motif was reported to selectively bind nicotinamide adenine dinucleotide (NAD+), defining a novel class of NAD+ riboswitches (NAD+-II) according to phylogenetic analysis. To reveal the three-dimensional architecture and the ligand-binding mode of this riboswitch, we solved the crystal structure of NAD+-II riboswitch in complex with NAD+. Strikingly and in contrast to class-I riboswitches that form a tight recognition pocket for the adenosine diphosphate (ADP) moiety of NAD+, the class-II riboswitches form a binding pocket for the nicotinamide mononucleotide (NMN) portion of NAD+ and display only unspecific interactions with the adenosine. We support this finding by an additional structure of the class-II RNA in complex with NMN alone. The structures define a novel RNA tertiary fold that was further confirmed by mutational analysis in combination with isothermal titration calorimetry (ITC), and 2-aminopurine-based fluorescence spectroscopic folding studies. Furthermore, we truncated the pnuC RNA motif to a short RNA helical scaffold with binding affinity comparable to the wild-type motif to allude to the potential of engineering the NAD+-II motif for biotechnological applications.
Antagonistic action of GPS2 and KDM1A at enhancers governs alternative macrophage activation by interleukin 4
Authors: Huang Zhiqiang , Efthymiadou Astradeni , Liang Ning , Fan Rongrong , Treuter Eckardt
Published: January 2023

The Th2 cytokine interleukin 4 (IL4) promotes macrophage differentiation into alternative subtypes and plays important roles in physiology, in metabolic and inflammatory diseases, in cancer and in tissue regeneration. While the regulatory transcription factor networks governing IL4 signaling are already well-characterized, it is currently less understood which transcriptional coregulators are involved and how they operate mechanistically. In this study, we discover that G protein pathway suppressor 2 (GPS2), a core subunit of the HDAC3 corepressor complex assembled by SMRT and NCOR, represses IL4-dependent enhancer activation in mouse macrophages. Our genome-wide and gene-specific characterization revealed that, instead of directly repressing STAT6, chromatin-bound GPS2 cooperates with SMRT and NCOR to antagonize enhancer activation by lysine demethylase 1A (KDM1A, LSD1). Mechanistically, corepressor depletion increased KDM1A recruitment to enhancers linked to IL4-induced genes, accompanied by demethylation of the repressive histone marks H3K9me2/3 without affecting H3K4me1/2, the classic KDM1A substrates for demethylation in other cellular contexts. This in turn caused enhancer and gene activation already in the absence of IL4/STAT6 and sensitized the STAT6-dependent IL4 responsiveness of macrophages. Thus, our work identified with the antagonistic action of a GPS2-containing corepressor complex and the lysine demethylase KDM1A a hitherto unknown epigenetic corepressor-coactivator switching mechanism that governs alternative macrophage activation.
Structural basis of Qng1-mediated salvage of the micronutrient queuine from queuosine-5′-monophosphate as the biological substrate
Authors: Hung Shr-Hau , Elliott Gregory I , Ramkumar Thakku R , Burtnyak Lyubomyr , McGrenaghan Callum J , Alkuzweny Sana , Quaiyum Samia , Iwata-Reuyl Dirk , Pan Xiaobei , Green Brian D , Kelly Vincent P , de Crécy-Lagard Valérie , Swairjo Manal A
Published: January 2023

Eukaryotic life benefits from—and ofttimes critically relies upon—the de novo biosynthesis and supply of vitamins and micronutrients from bacteria. The micronutrient queuosine (Q), derived from diet and/or the gut microbiome, is used as a source of the nucleobase queuine, which once incorporated into the anticodon of tRNA contributes to translational efficiency and accuracy. Here, we report high-resolution, substrate-bound crystal structures of the Sphaerobacter thermophilus queuine salvage protein Qng1 (formerly DUF2419) and of its human ortholog QNG1 (C9orf64), which together with biochemical and genetic evidence demonstrate its function as the hydrolase releasing queuine from queuosine-5′-monophosphate as the biological substrate. We also show that QNG1 is highly expressed in the liver, with implications for Q salvage and recycling. The essential role of this family of hydrolases in supplying queuine in eukaryotes places it at the nexus of numerous (patho)physiological processes associated with queuine deficiency, including altered metabolism, proliferation, differentiation and cancer progression.