bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of the outflow traced by water masers in the evolved star IRAS 18043—2116
Authors: Uscanga Lucero , Imai Hiroshi , Gómez José F. , Tafoya Daniel , Orosz Gabor , McCarthy Tiege P. , Hamae Yuhki , Amada Kei
Published: February 2024

We present the spectral and spatial evolution of H2O masers associated with IRAS 18043–2116, a well-known water fountain hosting a high-velocity collimated jet, which has been found in the observations with the 45 m telescope of Nobeyama Radio Observatory and the Australia Telescope Compact Array. We found new highest velocity components of the H2O masers, with which the resulting velocity spread of ≃ 540 km s−1 breaks the speed record of fast jets/outflows in this type of sources.
Introducing the MeerKAT Telescope: Studies of masers and their environment
Authors: Goedhart Sharmila
Published: February 2024

The 64-dish MeerKAT telescope was inaugurated in 2018 and has been conducting regular science operations since then. In the meantime, new observation modes have been under development. Spectral line modes are available, as well as L-, UHF- and S-band receivers. MeerKAT’s excellent sensitivity over a wide range of angular scales makes it an excellent choice for studies of HII regions, supernova remnants and planetary nebulae. In addition, an OH megamaser has been detected at z > 0.5 for the first time.
Multi-wavelength maser observations of the Extended Green Object G19.01—0.03
Authors: Williams Gwenllian M. , Cyganowski Claudia J. , Brogan Crystal L. , Hunter Todd R. , Ilee John D. , Nazari Pooneh , Smith Rowan J.
Published: February 2024

We report the detections of NH3(3,3) and 25 GHz and 278.3 GHz class I CH3OH maser emission associated with the outflow of the Extended Green Object G19.01–0.03 in sub-arcsecond resolution Atacama Large Millimeter/submillimeter Array (ALMA) and Karl G. Jansky Very Large Array (VLA) observations. For masers associated with the outer outflow lobes (> 12.5 ″ from the central massive young stellar object; MYSO), the spatial distribution of the NH3(3,3) masers is statistically indistinguishable from that of previously known 44 GHz Class I CH3OH masers, strengthening the connection of NH3(3,3) masers to outflow shocks. In sub-arcsecond resolution VLA observations, we resolve the 6.7 GHz Class II CH3OH maser emission towards the MYSO into a partial, inclined ring, with a velocity gradient consistent with the rotationally supported circumstellar disc traced by thermal gas emission.
Recombination lines and maser effects
Authors: Abraham Zulema
Published: February 2024

Maser effects occur in recombination lines when the plasma departs from local thermodynamic equilibrium (LTE). Its consequence is not as dramatic as that found in molecular masers, and therefore it is more difficult to recognize. Besides, it occurs in compact high density regions, and its lines fall at millimeter and submillimeter wavelengths, only recently available with good angular resolution. This review will focus on the theoretical aspects of maser recombination lines and on the recent detection of these masers in different astronomical objects.
Simultaneous observations of exited OH and methanol maser - coincidence and magnetic field
Authors: Kobak Agnieszka
Published: February 2024

We present the first results of simultaneous observations of the 6.035 GHz exited OH and 6.7 GHz methanol masers toward a sample of 10 high-mass young stellar objects (HMYSOs), observed using eMERLIN in 2020 and 2022. Searching for the coincidence and avoidance of these two maser transitions, we estimate physical conditions around central protostars. We identify Zeeman-splittings of the OH emission and determine the strength of the magnetic field. Combining it with linear polarization, we derive the magnetic field structure in these high-mass star-forming regions.
Expanded Maser Science Opportunities with the ALMA Wideband Sensitivity Upgrade
Authors: Brogan Crystal L.
Published: February 2024

The ALMA Project is embarking on a partner-wide initiative to at least double, and ultimately quadruple the correlated bandwidth of ALMA by @2030. This initiative is called the ALMA Wideband Sensitivity Upgrade (WSU). In this contribution, I briefly describe the main aspects of the upgrade and status. Then I provide several examples of how the WSU will enhance (sub)millimeter maser science by affording the ability to observe more diagnostic maser transitions (and thermal lines) with a single observation.
The Past, Present, and Groundbreaking Future of OH Megamaser Discoveries
Authors: Roberts Hayley , Darling Jeremy
Published: February 2024

OH megamasers (OHMs) are luminous masers found in (ultra-)luminous infrared galaxies ([U]LIRGs). OHMs are signposts of major gas-rich mergers associated with some of the most extreme star forming regions in our universe. The dominant OH masing line, occurring at 1667 MHz, can spoof the 1420 MHz neutral hydrogen (HI) line in untargeted HI emission line surveys. While only ∼120 OHMs are currently known, HI surveys on next-generation radio telescopes, such as the Square Kilometre Array (SKA) and its precursors, will detect unprecedented numbers of OHMs. This surge in detections will not only fundamentally change what we know about the OHM population, but will also unlock our ability to implement OHMs as tracers of major mergers and extreme star formation on cosmic scales. Here we present predictions for the number of OHMs that will be detected by these surveys. We also present our novel methods for identifying these interlopers using a k-Nearest Neighbors machine learning algorithm. Preliminary data from HI surveys on precursor SKA telescopes is being used to vet and strengthen these methods as well as give us a first look at a new era in OHM science. From a detection of one of the most luminous OHMs to the discovery of a megamaser at a record-shattering redshift, these new sources are glimpses into how our understanding of the known OHM population will soon be expanding and shifting rapidly and how they will influence our understanding of galaxy evolution.
Evolutionary Trends in Star Formation
Authors: Urquhart J. S.
Published: February 2024

Over the past 20 years, the Galactic plane has been surveyed at high resolution at wavelengths from 1 micron through to 20 cm. The combination of these surveys has produced large samples of deeply embedded young stars located across the Galactic disc. These continuum surveys are complemented by spectral line surveys of thermal, radio recombination, and molecular maser (OH, H2O, CH3OH) lines. The identified sources cover the whole range of evolutionary stages in the star formation process, allowing the physical properties of these stages to be measured. This information has been used to calculate the star formation efficiency and star formation rate of the Milky Way and to evaluate the impact of environment and location within the disc. This review provides an overview of some of the most significant studies in recent years and discusses how the evolutionary sequence has been used to investigate the correlation of other star formation tracers and maser associations.
Flaring Masers and Pumping
Authors: Gray M. D. , Etoka S. , Pimpanuwat B. , Richards A. M. S. , Cowie F. J.
Published: February 2024

We briefly consider the history of maser variability, and of flaring variability specifically. We consider six proposed flare generation mechanisms, and model them computationally with codes that include saturation and 3-D structure (the last mechanism is modelled in 1-D). Fits to observational light curves have been made for some sources, and we suggest that a small number of observational parameters can diagnose the flare mechanism in many cases. The strongest flares arise from mechanisms that can increase the number density of inverted molecules in addition to by geometrical effects, and in events where unsaturated quiescent masers become saturated during the flare.
GASKAP-OH: A New Deep Survey of Ground-State OH Masers and Absorption in the Southern Sky
Authors: Dawson J. R. , Breen S. L. ,   the GASKAP-OH Team
Published: February 2024

The Galactic ASKAP survey of OH (GASKAP-OH) is surveying the Milky Way Fourth Quadrant, the Galactic Centre, the Galactic Bulge and the Large Magellanic Cloud (LMC) in the 18-cm ground-state lines of the hydroxyl radical (OH), using Australia’s Square Kilometre Array Pathfinder (ASKAP) telescope. With an expected per-channel rms sensitivity of 36 mJy/beam in its shallowest regions, and a velocity channel width of 0.1 km s-1, GASKAP-OH is expected to discover hundreds of new star-formation and evolved star OH masers, as well as extensive absorption from quasi-thermal OH throughout the Galactic Plane. We here summarise the science goals and technical specifications of the survey, and report initial detection results from test observations. GASKAP-OH is expected to run for several years and is an open collaboration. Data products will be made available to the wider community as soon as they are verified.
A comprehensive model of maser polarization
Authors: Lankhaar Boy
Published: February 2024

Maser polarization observations have been successfully used to characterize magnetic fields towards a variety of astrophysical objects. Circular polarization yields the magnetic field strength of the maser source, and linear polarization yields information on the magnetic field morphology. Linear polarization can be produced when the maser saturates or through its anisotropic pumping. We present a comprehensive model of the polarization of masers. In contrast to regular excitation modeling, we relax the assumption of isotropically populated level populations, and model both the total population and level alignments. Through this approach, we obtain quantitative estimates on the anisotropic pumping of a variety of maser sources. In this way, the maser polarization may be related to the gas density, temperature, geometry and the magnetic field. Using the results of our modeling, we discuss, and give predictions, of the polarization of SiO, methanol, and water (mega)masers.
IC 485 : A candidate for a new disk-maser galaxy
Authors: Ladu Elisabetta , Tarchi Andrea , Castangia Paola , Surcis Gabriele , Braatz James A. , Panessa Francesca , Pesce Dominic
Published: February 2024

Fundamental physical quantities of the nuclear regions of the Active Galactic Nuclei can be obtained using megamaser studies. In particular, disk-masers associated with accretion disks around the supermassive black holes are used, through high angular resolution measurements, to trace the disk geometry, to estimate the BH mass and to measure accurate distances to their host galaxies. In this contribution, we present the first results in continuum and spectral-line mode of a high-sensitivity, multi-epoch VLBI study of the nuclear region of the megamaser LINER galaxy IC 485.
High-cadence 6.7 GHz methanol maser monitoring observations by Hitachi 32-m radio telescope
Authors: Yonekura Yoshinori , Tanabe Yoshihiro , Moriizumi Ren
Published: February 2024

We started high-cadence monitoring observations of 6.7 GHz methanol masers from Dec. 2012 using Hitachi 32-m radio telescope (Yonekura et al.(2016). Observations have been conducted basically every day. On average, 13 hours of observations have been made per day, amounting to 4000–5000 hours per year. The cadence varies by sources: one observation in 1–50 days. In addition to already known 29 sources (Tanabe et al. 2023 and references therein), we have newly identified ∼20 sources with periodic flux variability. We have also detected 5 sources with sudden flux rises in 2019–2022, including G358.93–0.03 which was confirmed to be associated with the accretion burst.
Megamaser Cosmology Project II : The prospects for measuring a 1% Ho and distances to high-z galaxies
Authors: Kuo Cheng-Yu , Pesce Dominic , Impellizzeri Violetta , Braatz James , Reid Mark
Published: February 2024

H2O megamaser emission from sub-parsec circumnuclear disks at the center of active galaxies allows a single-step, direct distance measurements to galaxies in the Hubble flow without any external calibration. Based on accurate distance determinations of six maser galaxies within 150 Mpc, the Megamaser Cosmology Project (MCP) team recently obtained H0 = 73.9± 3.0 km/s/Mpc (‘∼ 4% accuracy), independent of distance ladders and the cosmic microwave background. To further applying the megamaser technique to attain a 1% Ho measurement, detecting more high-quality disk maser systems is crucial. In this conference proceeding, we update the status of the MCP and discuss strategies of detecting additional high-quality disk maser galaxies within z ∼ 0.1. In addition, we show the prospects of reaching a 1% Ho measurement with the supreme sensitivity of the ngVLA. Finally, we demonstrate that applying the maser technique to distance measurements of high-z galaxies with future submm VLBI systems is promising and this will allow for investigation of the new tension between the ΛCDM model and the high-z Hubble diagram.
(Sub)mm Observations of Evolved Stars
Authors: Humphreys Elizabeth , Randall Suzanna , Asaki Yoshiharu , Bergman Per
Published: February 2024

Evolved stars on the asymptotic giant branch and red supergiants have multiple processes that can be studied in the (sub)mm, including stellar surfaces, circumstellar thermal gas and dust, and masers. Telescopes such as APEX and ALMA have opened the possibility to perform studies that are revealing new information on these, as well as on the role of binaries in shaping stellar winds and the evolution to planetary nebulae. Here, we discuss some recent results for (sub)mm observations towards evolved stars focusing particularly on masers. This includes SiO and water masers, as well as ALMA high angular resolution observations of HCN masers towards a carbon-rich star.
High resolution VLBI observations of 6.7GHz periodic methanol masers
Authors: Olech Mateusz
Published: February 2024

In the last 20 years a small group of 6.7GHz methanol maser sources displaying periodic variability have been identified. This variability is thought to reflect local processes linked to star formation. A number of models have been proposed e.g. colliding wind binary, protostellar pulsation, accretion on binary system. Recent studies of known sources as well as non-periodic flaring masers suggest an episodic accretion as a driving mechanism. We present the results of VLBI observation program aimed at studying known periodic methanol maser sources. High resolution maps of emission, source morphology and evolution in time will be discussed. Those results will help us fully understand the nature of maser periodicity in star forming regions.
Water megamaser emission in hard X-ray selected, highly obscured AGNs
Authors: Castangia Paola , Tarchi Andrea , Della Ceca Roberto , Caccianiga Alessandro , Severgnini Paola , Surcis Gabriele , Melis Andrea , Panessa Francesca , Malizia Angela , Bassani Loredana
Published: February 2024

We took profit of the availability of large catalogs of active galact nuclei (AGNs) selected in the hard X-ray from satellite missions (e. g., INTEGRAL, Swift/BAT) to investigate the relation between the occurrence of water maser emission and the X-ray properties of the nuclei on a statistically meaningful basis. Our studies demonstrate that the hard X-ray selection may significantly enhance the maser detection rate over comparably large optical or infrared surveys. Here, we report on a recent survey to search for water maser emission with the Sardinia Radio Telescope (SRT) in a sample of heavily absorbed AGN taken from the 70 months Swift/BAT catalog.
Torun methanol maser monitoring program
Authors: Wolak P. , Szymczak M. , Bartkiewicz A. , Durjasz M. , Kobak A. , Olech M.
Published: February 2024

Since 2009, the Torun 32 m radio telescope has been used to monitor a sample of ∼140 sources of the 6.7 GHz methanol maser emission. In 2022, the sample was extended to about 250 targets. Approximately three-quarters show variability greater than 10% on timescales of a few weeks to several years. The most significant results are detecting a few flare events and discovering about a dozen periodic variables with periods ranging from a month to a few years. Here, we present the preliminary analysis of the properties of periodic masers.
Annual parallax measurement of extreme OH/IR candidate star OH39.7+1.5
Authors: Watanabe Ryosuke
Published: February 2024

OH/IR stars are low- to intermediate-mass stars (about 0.5-8 solar masses) in the AGB phase, and are considered to be in the process of evolving from Mira variables to planetary nebulae. We aim to understand the evolutionary stages of these AGB stars by approaching them from astrometric VLBI observations with VERA. In 2017, we have started VLBI observations of several OH/IR stars including OH39.7+1.5 presented in this poster. We observed the H2O maser of OH39.7+1.5 and obtained an annual parallax of 0.55 ± 0.03 mas (distance D = 1.81 ± 0.12 kpc). Using this annual parallax, we revealed distribution (about 35 au square), internal motions, and expansion velocities (average about 15.4 ± 5.1 km s-1) of the maser spots. We compared expansion velocity of H2O maser with that of OH maser and found to be consistent across the error range. This suggests that the radial velocity of H2O gas around OH39.7+1.5 has reached a terminal velocity. OH39.7+1.5 has not data on annual parallax or proper motion in Gaia DR3, and this is the first time that annual parallax has been measured.
Maser Science with the African VLBI Network and MeerKAT
Authors: Chibueze James O.
Published: February 2024

The African VLBI Network (AVN) is slowly becoming a reality. A couple of successful fringe test observations have been conducted even as single-dish maser monitoring observations constitute the main activity on the telescopes (HartRAO 26 m and Ghana 32 m). Some of the recent observational results from the AVN telescopes includes detection of velocity drifts in masers. Although MeerKAT is largely designed for high sensitivity continuum and HI science, its bands cover some masers and is already making impressive discoveries. The need to grow the critical mass of radio astronomers in the African continent persists. The NWU 4-dish interferometer, the Nigeria 3.7 m radio telescope and the African Millimeter Telescope (AMT) are some of the initiatives that will significantly improve the statistics of radio astronomers in Africa.
H2O masers and host environments of FU Orionis and EX Lupi type low-mass eruptive YSOs
Authors: Marianna Szabó Zsófia , Gong Yan , Yang Wenjin , Menten Karl M. , Bayandina Olga S. , Cyganowski Claudia J. , Kóspál Ágnes , Ábrahám Péter , Belloche Arnaud , Wyrowski Friedrich
Published: February 2024

The FU Orionis (FUor) and EX Lupi (EXor) type objects are rare pre-main sequence low-mass stars undergoing accretion outbursts. Maser emission is widespread and is a powerful probe of mass accretion and ejection on small scales in star forming region. However, very little is known about the overall prevalence of water masers towards FUors/Exors. We present results from our survey using the Effelsberg 100-m telescope to observe the largest sample of FUors and EXors, plus additional Gaia alerted sources (with the potential nature of being eruptive stars), a total of 51 targets, observing the 22.2 GHz H2O maser, while simultaneously covering the NH3 23 GHz.
The Dynamics of the Outflow Structure in W49 N
Authors: Asanok Kitiyanee , Gray M.D. , Hirota T. , Sugiyama K. , Phetra M. , Kramer B.H. , Liu T. , Kim K.T. , Pimpanuwat B.
Published: February 2024

In this current study, we report only the preliminary result of the SiO v=0 Ј=5→4 emission toward W49 N at 230 GHz, observed using the ALMA telescope on September 29, 2018. The position–velocity diagram of the SiO emission shows a structure of a bipolar outflow and has a face-on orientation with an inclination angle of 36.4±0.4 degrees with respect to the line of sight. Here we summarize the calculated physical properties of its outflow.
The water and methanol masers in the face-on accretion system around the high-mass protostar G353.273+0.641
Authors: Motogi Kazuhito , Hirota Tomoya , Machida Masahiro N. , Tanaka Kei E. I. , Yonekura Yoshinori
Published: February 2024

We report on a direct comparison of VLBI maser data and ALMA thermal-emission data for the high-mass protostar G353.273+0.641. We detected a gravitationally-unstable disk by dust and a high-velocity jet traced by a thermal CO line by ALMA long-baselines (LB). 6.7 GHz CH3OH masers trace infalling streamlines inside the disk. The innermost maser ring indicates another compact accretion disk of 30 au. Such a nested system could be caused by angular momentum transfer by the spiral arms. 22 GHz H2O masers trace the jet-accelerating region, which are directly connecting the CO jet and the protostar. The recurrent maser flares imply episodic jet ejections per 1–2 yr, while typical separation of CO knots indicates a variation of outflow rate per 100 yr. Our study demonstrates that VLBI maser observations are still a powerful tool to explore detailed structures nearby high-mass protostars by combining ALMA LB.
Closing Remarks of the International Astronomical Union Symposium 380
Authors: Bartkiewicz Anna , Pihlström Ylva
Published: February 2024

We are pleased to summarise the IAU Symposium 380, Cosmic Masers: Proper Motion toward the Next-Generation Large Projects held on March 2023 March 20-24 in Kagoshima City, Japan. It is the sixth symposium focusing on astrophysical masers broadly used in research of star formation and evolved stars, astrometric measurements of the Milky Way galaxy, as well as studies of extragalactic environments.
Early Star Formation Traced by Water Masers
Authors: Ladeyschikov Dmitry
Published: February 2024

In this study, the correlation between 22 GHz water masers and other maser species with far infrared/submillimeter (FIR/sub-mm) sources is investigated. Comparing luminosity to mass ratio (L/M) of FIR/sub-mm clumps linked to different maser species, 22 GHz water masers have significantly lower L/M values than 6.7 GHz methanol and 1665 MHz OH masers. This suggests 22 GHz water masers may precede them in the evolution timeline of SFRs. The close association between water masers and FIR/sub-mm sources provides insight into maser pumping conditions and evolutionary stages.
Overview of the Maser Monitoring Organisation
Authors: Burns Ross A. , Kobak Agnieszka , Caratti o Garatti Alessio , Tolmachev Alexander , Volvach Alexandr , Alakoz Alexei , Wootten Alwyn , Bisyarina Anastasia , Dzodzomenyo Andrews , Sobolev Andrey , Bartkiewicz Anna , Aberfelds Artis , Stecklum Bringfried , Kramer Busaba , Macdonald Callum , Cyganowski Claudia , Colomer Fransisco , Miro Cristina Garcia , Brogan Crystal , Li Dalei , Smits Derck , Engels Dieter , Ladeyschikov Dmitry , Johnstone Doug , Popova Elena , Proven-Adzri Emmanuel , van den Heever Fanie , Orosz Gabor , Surcis Gabriele , Wu Gang , MacLeod Gordon , Linz Hendrik , Imai Hiroshi , van Langevelde Huib , Valtts Irina , Shmeld Ivar , Chibueze James O. , Brand Jan , Kumar Jayender , Green Jimi , Vorster Job , Eislöffel Jochen , Kim Jungha , Sugiyama Koichiro , Menten Karl , Immer Katharina , Rygl Kazi , Sunada Kazuyoshi , Kim Kee-Tae , Volvach Larisa , Moscadelli Luca , Jordan Lucas , Uscanga Lucero , Gray Malcolm , Szymczak Marian , Olech Mateusz , Hoare Melvin , Durjasz Michał , Uchiyama Mizuho , Shakhvorostova Nadya , Bayandina Olga , Wolak Pawel , Gulyaev Sergei , Khaibrakhmanov Sergey , Breen Shari , Goedhart Sharmila , Casu Silvia , Ellingsen Simon , Paulson Sonu Tabitha , Kurtz Stan , Weston Stuart , Yoshihiro Tanabe , Natusc Tim , Hunter Todd , Hirota Tomoya , Baan Willem , Vlemmings Wouter , Chen Xi , Gong Yan , Yonekura Yoshinori , Szabó Zsófia Marianna , Abraham Zulema
Published: February 2024

The Maser Monitoring Organisation is a collection of researchers exploring the use of time-variable maser emission in the investigation of astrophysical phenomena. The forward directed aspects of research primarily involve using maser emission as a tool to investigate star formation. Simultaneously, these activities have deepened knowledge of maser emission itself in addition to uncovering previously unknown maser transitions. Thus a feedback loop is created where both the knowledge of astrophysical phenomena and the utilised tools of investigation themselves are iteratively sharpened. The project goals are open-ended and constantly evolving, however, the reliance on radio observatory maser monitoring campaigns persists as the fundamental enabler of research activities within the group.
Fine structure and refractive scattering of the H2O maser in star-forming region W49N
Authors: Shakhvorostova N. N. , Moran J. M. , Alakoz A. V. , Imai H. , Gwinn C. R. , Sobolev A. M.
Published: February 2024

We used the unprecedented resolution of ∼25 μas of the VLBI array formed with the RadioAstron satellite to study the structures of H2O maser spots in the star forming region W49N. We found that anisotropic diffractive scattering of the ISM dominates the images of the maser spot, but does not completely blur them. The refractive scattering floor is about 0.001 in visibility at a baseline of 8 Gλ.
Maser polarization simulation in an evolving star: effect of magnetic field on SiO maser in the circumstellar envelope
Authors: Phetra M. , Gray M. D. , Asanok K. , Kramer B. H. , Sugiyama K. , Etoka S. , Nuntiyakul W.
Published: February 2024

Maser polarization changes during a pulsation in the CSE of an AGB star are related in a complicated way to the magnetic field structure. 43 GHz SiO maser transitions are useful for polarization study because of their relatively simple Zeeman splitting structure and their location. This work uses 3D maser simulation to investigate the effect of the magnetic field on maser polarization with different directions. The results show that linear polarization depends on the magnetic direction while circular polarization is less significant. The EVPA changes through π/2 at an angle of around 50 degrees, approximately the Van Vleck angle. The EVPA rotation result from 3D maser simulation is consistent with results from 1D simulations, and may explain the 90 degree change of the EVPA within a single cloud in the observational cases of TX Cam and R Cas.
Psychometric Properties of the Hindi Version of the Behavioral Inhibition System/Behavioral Activation System Scale
Authors: Kumari Rajbala , Ranjan Jay Kumar , Verma Saroj
Published: February 2024

Abstract: Aim: The Behavioral Inhibition and Activation Scale is a popular instrument that assesses an individual's responsiveness to reward and punishment. It is widely translated and validated in different languages. However, the Hindi version of this scale is not yet available. The present study aimed to adapt the BIS/BAS scale into Hindi and examine its psychometric properties and factor structure. Method: The original BIS/BAS scale was translated into Hindi using the translation and back-translation method. The translated Hindi version along with the NEO-FFI and HADS was administered on 200 participants. Psychometric properties, i.e., reliability, validity, and factor structure, were estimated. Result: Cronbach’s α coefficient ranged between .68 and .80, while test–retest reliability ranges between .85 and .92. The validity is also adequate. The findings support the five-factor structure of the BIS/BAS scale. Limitations: The present study has a relatively small sample, which is drawn from only one Hindi-speaking region of India. Conclusion: It was found that the Hindi version of the BIS/BAS scale is a reliable and valid tool with good psychometric properties.
Ocean Coupling Limits Rupture Velocity of Fastest Observed Ice Shelf Rift Propagation Event
Authors: Olinger Stephanie D. , Lipovsky Bradley P. , Denolle Marine A.
Published: February 2024

The Antarctic ice sheet is buttressed by floating ice shelves that calve icebergs along large fractures called rifts. Despite the significant influence exerted by rifting on ice shelf geometry and buttressing, the scarcity of in situ observations of rift propagation contributes considerable uncertainty to understanding rift dynamics. Here, we report the first‐ever seismic recording of a multiple‐kilometer rift propagation event. Remote sensing and seismic recordings reveal that a rift in the Pine Island Glacier Ice Shelf extended 10.53 km at a speed of 35.1 m/s, the fastest known ice fracture at this scale. We simulate ocean‐coupled rift propagation and find that the dynamics of water flow within the rift limit the propagation rate, resulting in rupture two orders of magnitude slower than typically predicted for brittle fracture. Using seismic recordings of the elastic waves generated during rift propagation, we estimate that ocean water flows into the rift at a rate of at least 2,300 m3/s during rift propagation and causes mixing in the subshelf cavity. Our observations support the hypotheses that large ice shelf rift propagation events are brittle, hydrodynamically limited, and exhibit sensitive coupling with the surrounding ocean.
Capturing the Relative‐Humidity‐Sensitive Gas–Particle Partitioning of Organic Aerosols in a 2D Volatility Basis Set
Authors: Serrano Damha Camilo , Cummings Bryan E. , Schervish Meredith , Shiraiwa Manabu , Waring Michael S. , Zuend Andreas
Published: February 2024

Aerosol water affects the physicochemical properties and mass concentration of organic aerosols (OA), but it is typically omitted by air quality, weather, and climate models. We compare two classes of simplified models to estimate the OA water uptake and gas–particle partitioning of organic compounds. One class uses a single‐hygroscopicity‐parameter (κ) approach while the other is based on the reduced‐complexity Binary Activity Thermodynamics (BAT) model. We show that a BAT‐based two‐dimensional volatility basis set (VBS) model always predicts a higher OA mass concentration at elevated relative humidity (RH), for example, ∼16% at 80% RH, than any variation of the κ‐based method considered—even when BAT‐VBS predicts a lower water uptake. The main reason being that the BAT‐VBS model captures variations in effective saturation mass concentration of organics (C*) with RH, a feature that other VBS methods lack. The BAT‐VBS framework offers an efficient, RH‐sensitive treatment for reduced‐complexity OA modeling.
Submesoscale Variability and Basal Melting in Ice Shelf Cavities of the Amundsen Sea
Authors: Shrestha Kalyan , Manucharyan Georgy E. , Nakayama Yoshihiro
Published: February 2024

Melting of ice shelves can energize a wide range of ocean currents, from three‐dimensional turbulence to relatively large‐scale boundary currents. Here, we conduct high‐resolution simulations of the western Amundsen Sea to show that submesoscale eddies are prevalent inside ice shelf cavities. The simulations indicate energetic submesoscale eddies at the top and bottom ocean boundary layers, regions with sharp topographic slopes and strong lateral buoyancy gradients. These eddies play a substantial role in the vertical and lateral (along‐isopycnal) heat advection toward the ice shelf base, enhancing the basal melting in all simulated cavities. In turn, the meltwater provides strong buoyancy gradients that energize the submesoscale variability, forming a positive loop that could affect the overall efficiency of heat exchange between the ocean and the ice shelf cavity. Our study implies that submesoscale‐induced enhancement of basal melting may be a ubiquitous process that needs to be parameterized in coarse‐resolution climate models.
First Results From REPTile‐2 Measurements Onboard CIRBE
Authors: Li Xinlin , Selesnick Richard , Mei Yang , O’Brien Declan , Hogan Benjamin , Xiang Zheng , Khoo Lengying , Zhao Hong , Schiller Quintin , Temerin Michael , Baker Daniel N.
Published: February 2024

CIRBE (Colorado Inner Radiation Belt Experiment), a 3U CubeSat, was launched on 15 April 2023 into a sun synchronous orbit (97.4° inclination and 509 km altitude). The sole science payload onboard is REPTile‐2 (Relativistic Electron and Proton Telescope integrated little experiment—2), an advanced version of REPTile which operated in space between 2012 and 2014. REPTile‐2 has 60 channels for electrons (0.25–6 MeV) and 60 channels for protons (6.5–100 MeV). It has been working well, capturing detailed dynamics of the radiation belt electrons, including several orders of magnitude enhancements of the outer belt electrons after an intense magnetic storm, multiple “wisps”‐ an electron precipitation phenomenon associated with human‐made very low frequency (VLF) waves in the inner belt, and “drift echoes” of 0.25–1.4 MeV electrons across the entire inner belt and part of the outer belt. These new observations provide opportunities to test the understanding of the physical mechanisms responsible for these features.
Warming Climate‐Induced Changes in Cloud Vertical Distribution Possibly Exacerbate Intra‐Atmospheric Heating Over the Tibetan Plateau
Authors: Zhao Yang , Li Jiming , Wang Yifei , Zhang Weiyuan , Wen Deyu
Published: February 2024

The complex and diverse cloud vertical distribution (CVD) largely impacts radiative and precipitation properties of clouds. Using 10‐year active satellite observations, we classified CVD over the Tibetan Plateau into 12 categories and found that overlapping clouds have less frequency but stronger radiative effect, heating rate and larger precipitation (partly reflecting the seeding effect) compared with single‐layer non‐strong convective clouds. Under a warming climate due to uniform sea surface temperature increase of 4K (quadrupling CO2 increase), extremely high (>10 km) ice clouds will increase, particularly those below the tropopause will increase slightly (largely), accompanied by clear (weak) increases in stratospheric clouds. Simultaneously, a moderate to rapid decrease will occur in clouds below 10 km. Such CVD changes could further exacerbate tropopause warming. The probability of cloud overlap is also likely to increase in warmer climates, thus possibly further causing non‐convective cloud systems with stronger intra‐atmospheric heating, larger precipitation intensity and proportion.
Terrestrial Evapotranspiration Over China From 1982 to 2020: Consistency of Multiple Data Sets and Impact of Input Data
Authors: Mao Yuna , Bai Jiaxin , Wu Guocan , Xu Lin , Yin Changjian , Feng Fei , He Yanyi , Zhang Zhengtai , Wang Kaicun
Published: February 2024

Due to limited direct measurements, regional or global terrestrial evapotranspiration (ET) is generally derived from a combination of meteorological and satellite observations. Although the inhomogeneity of the observed climate data has been widely reported, its impact on the calculated ET has not been adequately quantified. This study aimed to calculate ET using the modified Penman‐Monteith (MPM) model with raw and homogenized meteorological data. Additionally, we compared the calculated ET with those estimates from variable methods (water balance, satellite‐based, and reanalysis) in China and its six major river basins from 1982 to 2020. During the overlapping period of 1997–2018, ET calculated from raw input data decreased slightly at −0.39 mm yr−2 (p = 0.64) in China, whereas homogenized ET showed a significant increasing trend of 0.93 mm yr−2 (p = 0.02), with a better agreement with water balance ET (1.93 mm yr−2, p = 0). Global Land Evaporation Amsterdam Model (GLEAM) and Modern‐Era Retrospective Analysis for Research and Applications, version 2 (MERRA2) could reproduce the increasing trends with 2.08 mm yr−2 (p = 0) and 2.59 mm yr−2 (p = 0). The intercomparison of input variables (solar radiation, relative humidity, wind speed, precipitation, and air temperature) among ET products revealed substantial differences, which can account for the discrepancies in ET estimates. Homogenized ET, GLEAM and MERRA2 exhibited significant increasing trends in China and most river basins from 1982 to 2020. Our findings underscore the importance of utilizing homogenized input data for more accurate ET estimation.
Global Distribution and Volume of Cryptomare and Visible Mare on the Moon From Gravity and Dark Halo Craters
Authors: Izquierdo Kristel , Sori Michael M. , Checketts Brianne , Hampton Isabella , Johnson Brandon C. , Soderblom Jason M.
Published: February 2024

The present‐day distribution of mare basalts on the Moon is an important constraint on the timing, duration, and flux of volcanism on the Moon. In this work, we find the global distribution of visible mares and cryptomares using the effective density (ρeff) of the Moon, which is sensitive to the vertical density distribution of the crust. We compute ρeff using the Gravity Recovery and Interior Laboratory (GRAIL) data and the Lunar Orbiter Laser Altimeter (LOLA) topography data. We apply this ρeff approach to the search of cryptomare for the first time, and we use a higher resolution grid and larger search area to constrain visible mare thicknesses compared to previous work. We use a Bayesian approach to find the distribution of mare thicknesses and density gradients of the underlying crust that is consistent with the localized ρeff. Assuming a bulk density of the mare basalts of 3,460 kg/m3, we find a mean visible mare thickness of km which is consistent with previous work. We find a candidate cryptomare volume of km3 representing more than half of the total mare volume on Moon. This volume is consistent with the higher end of the previously proposed values. Finally, we search for dark halo craters (DHC) globally to obtain geologic evidence of cryptomares and find 258 craters. Our results are consistent with extensive ancient volcanism, which explains the previously identified discrepancy between the early high volcanic flux predicted by thermal models of the Moon and the dearth of ancient volcanic deposits currently exposed.
Quantifying and Reducing the Operator Effect in LSPIV Discharge Measurements
Authors: Bodart G. , Le Coz J. , Jodeau M. , Hauet A.
Published: February 2024

Operator choices, both in acquiring the video and data and in processing them, can be a prominent source of error in image‐based velocimetry methods applied to river discharge measurements. The Large Scale Particle Image Velocimetry (LSPIV) is known to be sensitive to the parameters and computation choices set by the user, but no systematic comparisons with discharge references or intercomparisons have been conducted yet to evaluate this operator effect in LSPIV. In this paper, an analysis of a video gauging intercomparison, the Video Globe Challenge 2020, is proposed to evaluate such operator effect. The analysis is based on the gauging reports of the 15 to 23 participants using the Fudaa‐LSPIV software and intents to identify the most sensitive parameters for the eight videos. The analysis highlighted the significant impact of the time interval, the grid points and the filters on the LSPIV discharge measurements. These parameters are often inter‐dependent and should be correctly set together to strongly reduce the discharge errors. Based on the results, several automated tools were proposed to reduce the operator effect. These tools consist of several parameter assistants to automatically set the orthorectification resolution, the grid and the time interval, and of a sequence of systematic and automatic filters to ensure reliable velocity measurements used for discharge estimation. The application of the assisted LSPIV workflow using the proposed tools leads to significant improvements of the discharge measurements with strong reductions of the inter‐participant variability. On the eight videos, the mean interquartile range of the discharge errors is reduced from 17% to 5% and the mean discharge bias is reduced from −9% to 1% with the assisted LSPIV workflow. The remaining inter‐participant variability is mainly due to the user‐defined surface velocity coefficient α.
Quantifying the Precipitation, Evapotranspiration, and Soil Moisture Network's Interaction Over Global Land Surface Hydrological Cycle
Authors: Mondal Somnath , Mishra Ashok
Published: February 2024

Enhancing our understanding of the intricate interplay among hydro‐climatic processes is crucial for a comprehensive assessment of water availability and climate extremes across global land regions. Here, we propose an integrated framework to investigate networks of the global fields of multiple hydrological variables (Precipitation, Evapotranspiration, Soil Moisture). We apply a two‐layer complex network concept to formulate the independent networks of each hydrological variable and their interactions. Intra‐ (Single‐layer) and cross‐ (two‐layer) network coefficients are derived from the formulated hydrological network to quantify the linkage, spatial connection density, and scale for the independent hydrological fields (or variables) and their interactions. The joint distribution of the intra‐network coefficients reveals multiple spatial scales of connectivity for a moderately well‐connected location in case of evapotranspiration and soil moisture. With increasing global mean temperature, spatially synchronized evapotranspiration over such a large scale may lead to multi‐continental droughts and heatwaves. Furthermore, the (cross‐) network coefficients have identified regions acting as “bottlenecks” for moisture flow and the water‐dominated areas with less evaporative actions. The contrasting features of two‐layer network coefficients have provided a qualitative picture of moisture circulation and recirculation over many hydrological hotspot regions, such as the Amazonian basin, Indian subcontinents, and the Sahel region. The derived results can be employed to gain insights into the global water cycle’s multiple interacting processes (e.g., land‐atmosphere interactions).
Advanced Analytical Model for Interpreting Oscillatory Pumping Tests With Wellbore Skin and Rate‐Dependent Skin Effects
Authors: Mahdavi Ali , Kurylyk Barret L. , Lin Yin‐Fang
Published: February 2024

Oscillatory pumping tests presents a potential advancement in aquifer testing as they minimize hydraulic perturbations and result in no net water abstraction or injection. However, aquifer property estimates can be less accurate if they are compromised by well head losses during the pumping test. Currently, oscillatory pumping test models ignore these losses. The objective of this study is to develop and evaluate an analytical solution that can interpret oscillatory pumping test data affected by rate‐dependent skin losses. Accordingly, the sensitivity of the drawdown response to small variations in aquifer and well parameters was analyzed. In addition, a previous field aquifer test was analyzed to evaluate the feasibility of the solution for aquifer parameter estimation. The results indicate that neglecting the rate‐dependent skin effect can lead to substantial errors in the determination of aquifer parameters such as transmissivity and storativity. Additionally, the proposed solution effectively reproduces the sharp groundwater level peaks observed in field data, whereas the solution that does not consider the rate‐dependent skin effect greatly underestimates the peak values.
Poorer Countries Face Heavier Consequences of Climate Change
Authors: Kornei Katherine
Published: February 2024

As forests shift to higher latitudes, nations to reckon with losses of both market and nonmarket ecosystem benefits.
An early screening model for preeclampsia: utilizing zero-cost maternal predictors exclusively
Authors: Wang Lei , Ma Yinyao , Bi Wenshuai , Meng Chenwei , Liang Xuxia , Wu Hua , Zhang Chun , Wang Xiaogang , Lv Hanlin , Li Yuxiang
Published: February 2024

To provide a reliable, low-cost screening model for preeclampsia, this study developed an early screening model in a retrospective cohort (25,709 pregnancies) and validated in a validation cohort (1760 pregnancies). A data augmentation method (α-inverse weighted-GMM + RUS) was applied to a retrospective cohort before 10 machine learning models were simultaneously trained on augmented data, and the optimal model was chosen via sensitivity (at a false positive rate of 10%). The AdaBoost model, utilizing 16 predictors, was chosen as the final model, achieving a performance beyond acceptable with Area Under the Receiver Operating Characteristic Curve of 0.8008 and sensitivity of 0.5190. All predictors were derived from clinical characteristics, some of which were previously unreported (such as nausea and vomiting in pregnancy and menstrual cycle irregularity). Compared to previous studies, our model demonstrated superior performance, exhibiting at least a 50% improvement in sensitivity over checklist-based approaches, and a minimum of 28% increase over multivariable models that solely utilized maternal predictors. We validated an effective approach for preeclampsia early screening incorporating zero-cost predictors, which demonstrates superior performance in comparison to similar studies. We believe the application of the approach in combination with high performance approaches could substantially increase screening participation rate among pregnancies.
Bile salt hydrolase catalyses formation of amine-conjugated bile acids
Authors: Rimal Bipin , Collins Stephanie L. , Tanes Ceylan E. , Rocha Edson R. , Granda Megan A. , Solanki Sumeet , Hoque Nushrat J. , Gentry Emily C. , Koo Imhoi , Reilly Erin R. , Hao Fuhua , Paudel Devendra , Singh Vishal , Yan Tingting , Kim Min Soo , Bittinger Kyle , Zackular Joseph P. , Krausz Kristopher W. , Desai Dhimant , Amin Shantu , Coleman James P. , Shah Yatrik M. , Bisanz Jordan E. , Gonzalez Frank J. , Vanden Heuvel John P. , Wu Gary D. , Zemel Babette S. , Dorrestein Pieter C. , Weinert Emily E. , Patterson Andrew D.
Published: February 2024

Bacteria in the gastrointestinal tract produce amino acid bile acid amidates that can affect host-mediated metabolic processes1–6; however, the bacterial gene(s) responsible for their production remain unknown. Herein, we report that bile salt hydrolase (BSH) possesses dual functions in bile acid metabolism. Specifically, we identified a previously unknown role for BSH as an amine N-acyltransferase that conjugates amines to bile acids, thus forming bacterial bile acid amidates (BBAAs). To characterize this amine N-acyltransferase BSH activity, we used pharmacological inhibition of BSH, heterologous expression of bsh and mutants in Escherichia coli and bsh knockout and complementation in Bacteroides fragilis to demonstrate that BSH generates BBAAs. We further show in a human infant cohort that BBAA production is positively correlated with the colonization of bsh-expressing bacteria. Lastly, we report that in cell culture models, BBAAs activate host ligand-activated transcription factors including the pregnane X receptor and the aryl hydrocarbon receptor. These findings enhance our understanding of how gut bacteria, through the promiscuous actions of BSH, have a significant role in regulating the bile acid metabolic network.
Mechanism of millisecond Lys48-linked poly-ubiquitin chain formation by cullin-RING ligases
Authors: Liwocha Joanna , Li Jerry , Purser Nicholas , Rattanasopa Chutima , Maiwald Samuel , Krist David T. , Scott Daniel C. , Steigenberger Barbara , Prabu J. Rajan , Schulman Brenda A. , Kleiger Gary
Published: February 2024

E3 ubiquitin ligases, in collaboration with E2 ubiquitin-conjugating enzymes, modify proteins with poly-ubiquitin chains. Cullin-RING ligase (CRL) E3s use Cdc34/UBE2R-family E2s to build Lys48-linked poly-ubiquitin chains to control an enormous swath of eukaryotic biology. Yet the molecular mechanisms underlying this exceptional linkage specificity and millisecond kinetics of poly-ubiquitylation remain unclear. Here we obtain cryogenic-electron microscopy (cryo-EM) structures that provide pertinent insight into how such poly-ubiquitin chains are forged. The CRL RING domain not only activates the E2-bound ubiquitin but also shapes the conformation of a distinctive UBE2R2 loop, positioning both the ubiquitin to be transferred and the substrate-linked acceptor ubiquitin within the active site. The structures also reveal how the ubiquitin-like protein NEDD8 uniquely activates CRLs during chain formation. NEDD8 releases the RING domain from the CRL, but unlike previous CRL–E2 structures, does not contact UBE2R2. These findings suggest how poly-ubiquitylation may be accomplished by many E2s and E3s.