bluuebunny/crossref_metadata_2025 huggingface dataset:
Association between use of novel glucose-lowering drugs and COVID-19 hospitalization and death in patients with type 2 diabetes: a nationwide registry analysis
Authors: Ferrannini Giulia , Lund Lars H , Benson Lina , Rizzo Manfredi , Almahmeed Wael , Rosano Giuseppe M C , Savarese Gianluigi , Cosentino Francesco
Published: August 2022

Aims

Type 2 diabetes (T2DM) in patients with coronavirus disease-19 (COVID-19) is associated with a worse prognosis. We separately investigated the associations between the use of sodium-glucose cotransporter 2 inhibitors (SGLT2i), glucagon-like peptide-1 receptor agonists (GLP-1 RA), and dipeptidyl peptidase-4 inhibitors (DPP-4i), and the risk of COVID-19 hospitalization and death.

Methods and results

Patients with T2DM registered in the Swedish National Patient Registry and alive on 1 February 2020 were included. ‘Incident severe COVID-19’ was defined as the first hospitalization and/or death from COVID-19. A modified Poisson regression approach was applied to a 1:1 propensity score-matched population receiving vs. not receiving SGLT2i, GLP-1 RA, and DPP-4i to analyse the associations between their use and (I) incident severe COVID-19 and (II) risk of 30-day mortality in patients hospitalized for COVID-19.

Among 344 413 patients, 39 172 (11%) were treated with SGLT2i, 34 290 (10%) with GLP-1 RA, and 53 044 (15%) with DPP-4i; 9538 (2.8%) had incident severe COVID-19 by 15 May 2021. SGLT2i and DPP-4i were associated with a 10% and 11% higher risk of incident severe COVID-19, respectively, whereas there was no association for GLP-1 RA. DPP-4i was also associated with a 10% higher 30-day mortality in patients hospitalized for COVID-19, whereas there was no association for SGLT2i and GLP-1 RA.

Conclusion

SGLT2i and DPP-4i use were associated with a higher risk of incident severe COVID-19. DPP-4i use was associated with higher 30-day mortality in patients with COVID-19, whereas SGLT2i use was not. No increased risk for any outcome was observed with GLP-1 RA.
GPS/BDS precise point positioning with B2b products for high-rate seismogeodesy: application to the 2021Mw 7.4 Maduo earthquake
Authors: Fang Rongxin , Lv Huanghui , Hu Zhigang , Wang Guangxing , Zheng Jiawei , Zhou Renyu , Xiao Kun , Li Min , Liu Jingnan
Published: August 2022

Precise point positioning (PPP) can measure ground motions with a centimetre-level accuracy using only one receiver. It has been widely used in earthquake monitoring and earthquake early warning (EEW) systems. However, traditional PPP highly depends on well-established and robust internet infrastructure for data communication. Along with the broadcast ephemeris, the orbit and clock corrections transmitted by the B2b signals of BeiDou Navigation Satellite System (BDS) can be used to recover the precise products of GPS and BDS. Since the B2b products, namely the satellite state parameter messages, are accessible even without internet infrastructure, PPP with B2b signals is more suitable for real-time applications. This study witnesses the application of PPP with B2b products in seismic monitoring for the first time. The shake table experiments demonstrate that PPP with B2b can reach a millimetre-level accuracy in horizontal in earthquake monitoring for GPS-only, BDS-only and GPS/BDS combination. The application to the 2021 Mw 7.4 Maduo earthquake shows that the accuracies of seismic displacements derived from GPS-only PPP with B2b products are 1.7, 2.4 and 1.7 cm in east, north and vertical components, compared with those from GPS-only PPP with final precise products. We therefore conclude that PPP with B2b products has a promising prospect in seismogeodesy and related applications such as EEW and rapid hazard response.
Can Sex-Specific Metabolic Rates Provide Insight into Patterns of Metabolic Scaling?
Authors: Somjee Ummat , Shankar Anusha , Falk Jay J
Published: August 2022

Females and males can exhibit striking differences in body size, relative trait size, physiology, and behavior. As a consequence, the sexes can have very different rates of whole-body energy use, or converge on similar rates through different physiological mechanisms. Yet many studies that measure the relationship between metabolic rate and body size only pay attention to a single sex (more often males), or do not distinguish between sexes. We present four reasons why explicit attention to energy-use between the sexes can yield insight into the physiological mechanisms that shape broader patterns of metabolic scaling in nature. First, the sexes often differ considerably in their relative investment in reproduction, which shapes much of life-history and rates of energy use. Second, males and females share a majority of their genome but may experience different selective pressures. Sex-specific energy profiles can reveal how the energetic needs of individuals are met despite the challenge of within-species genetic constraints. Third, sexual selection often pushes growth and behavior to physiological extremes. Exaggerated sexually selected traits are often most prominent in one sex, can comprise up to 50% of body mass, and thus provide opportunities to uncover energetic constraints of trait growth and maintenance. Finally, sex-differences in behavior such as mating-displays, long-distance dispersal, and courtship can lead to drastically different energy allocation among the sexes; the physiology to support this behavior can shape patterns of metabolic scaling. The mechanisms underlying metabolic scaling in females, males, and hermaphroditic animals can provide opportunities to develop testable predictions that enhance our understanding of energetic scaling patterns in nature.
Quill Mites of the Family Syringophilidae (Acariformes: Prostigmata) Associated With the New World and African Parrots (Psittaciformes: Psittacidae) With the Description of Eight New Species
Authors: Marciniak–Musial Natalia , Sikora Bozena
Published: August 2022

In this paper, we review the quill mite fauna of the family Syringophilidae Lavoipierre, 1953 (Acariformes: Prostigmata) associated with New World and African parrots (Aves: Psittaciformes: Psittacidae), and describe eight new species including: Neoaulobia unsoeldi Marciniak-Musial & Sikora sp. nov. from the Burrowing Parakeet Cyanoliseus patagonus in Argentina; Lawrencipicobia arini Marciniak-Musial & Sikora sp. nov. from the Black-headed Parrot Pionites melanocephalus in Surinam; L. ararauna Marciniak-Musial & Sikora sp. nov. from the Black-headed Parrot Ara ararauna in Brazil; L. touiti Marciniak-Musial & Sikora sp. nov. from the Golden-tailed Parrotlet Touit surdus in Brazil; Rafapicobia valdiviana Marciniak-Musial & Sikora sp. nov. from the Burrowing Parrot Cyanoliseus patagonus in Brazil; R. pyrrhura Marciniak-Musial & Sikora sp. nov. from the Green-cheeked Parakeet Pyrrhura molinae in Bolivia; R. xanthopterygius Marciniak-Musial & Sikora sp. nov. from the Blue-winged Parrotlet Forpus xanthopterygius in Brazil; and R. trainidadi Marciniak-Musial & Sikora sp. nov. from the Lilac-tailed Parrotlet Touit batavicus in Trinidad and Tobago. Additionally, we note fifteen new host species and many new locality records for the previously described taxa, and provide the keys for all species associated with psittaciform birds. Finally, we discuss the host–parasite relationships between syringophilid mites and parrots.
Recurrent Antibiotic Use in Kentucky Children With 6 Years of Continuous Medicaid Enrollment
Authors: Wattles Bethany A , Smith Michael J , Feygin Yana , Jawad Kahir S , Bhadury Sagnik , Sun Jingchao , Kong Maiying , Woods Charles R
Published: August 2022

Background

Little is known about the distribution of antibiotic use in individual children over time. The amoxicillin index is a recently proposed metric to assess first-line antibiotic prescribing to children.

Methods

We constructed a cohort of continuously enrolled Medicaid children using enrollment claims from 2012 to 2017. Pharmacy claims were used to identify antibiotic prescription data.

Results

Among 169 724 children with 6 years of Medicaid enrollment, 10 804 (6.4%) had no antibiotic prescription claims during the study period; 43 473 (25.6%) had 1-3 antibiotics; 34 318 (20.2%) had 4-6 antibiotics; 30 994 (18.3%) had 7-10; 35 018 (20.6%) had 11-20; and 15 117 (8.9%) children had more than 20 antibiotic prescriptions. Overall, the population had a median total of 6 antibiotic prescriptions during the study period, but use was higher in certain patient groups: younger age (8 antibiotic fills over the 6-year period, [IQR 4-14]), White children (7 [IQR 3-13], compared to 3 [IQR 1-6] in Black children), rural settings (9 [IQR 4-15]) and chronic conditions (8 [IQR 4-15]). Higher-use groups also had lower rates of amoxicillin fills, reported as amoxicillin indices.

Conclusions

Antibiotic use is common among most children insured by Kentucky Medicaid. A number of fills over time were higher in younger children, and in White children, children living in rural settings and children with chronic conditions. Patients with higher recurrent antibiotic use are important targets for designing high-impact antibiotic stewardship efforts.
Drivers of Prolonged Outpatient Antibiotic Therapy for Urinary Tract Infections and Community-Acquired Pneumonia
Authors: Shah Rohan M , Sun Shan , Shteynberg Emily , Scardina Tonya , Whitmer Grant , Patel Sameer J
Published: August 2022

Background

Variability exists in treatment duration for community-acquired pneumonia (CAP) and urinary tract infection (UTI) in children and may be associated with non-clinical factors.

Methods

A retrospective study was conducted of patients treated for outpatient CAP and UTI in a children’s hospital network from 2016 to 2019. Multivariable logistic regression was performed to identify predictors of long antibiotic duration (≥10 days). Hospitalization within 30 days was determined.

Results

Overall, 2124 prescriptions for CAP and 1116 prescriptions for UTI were included. Prescriptions were ≥10 days in 59.9% and 47.6% for CAP and UTI, respectively. Long durations were more common in the emergency department (ED) than in clinics for UTI’s (P = .0082), and more common in convenient care for CAP (P = .045). In UTI’s, Asian and Hispanic patients received shorter durations than white patients. Younger children had greater odds of long duration for both diagnoses. Medicaid insurance was associated with long therapy for UTI (OR: 1.660, P = .0042) and CAP (OR: 1.426, P = .0169). Residents and fellows were less likely to give long durations than attending physicians (P < .0001). APNs were more likely to administer long therapies in CAP (P = .0062). Subsequent hospitalizations were uncommon for UTI (n = 10) and CAP (n = 20).

Conclusions

Younger age, Medicaid insurance, ED, and convenient care visits were associated with a long duration of therapy. Residents and fellows were less likely to give long durations.
Association of Catalase Gene Polymorphisms with Idiopathic Nephrotic Syndrome in a Chinese Pediatric Population
Authors: Shi Jianrong , Li Wei , Tao Ran , Zhou Dongming , Guo Yajun , Fu Haidong , Sun Anna , Zhang Junfeng , Mao Jianhua
Published: August 2022

Objective

Our aim was to investigate the association between gene polymorphisms in catalase (CAT), a well-known oxidative stress regulator, and susceptibility to idiopathic nephrotic syndrome (INS) or responses to steroid therapy in a Chinese pediatric population.

Methods

We analyzed 3 CAT single-nucleotide polymorphisms (SNVs; rs7943316, rs769217, and rs12270780) using multi-polymerase chain reaction combined with next-generation sequencing in 183 INS patients and 100 healthy controls.

Results

For the allele and genotype frequencies of the CAT SNVs, no significant differences were observed between INS patients and controls. Patients with C allele of CAT rs769217 had a higher risk of developing steroid-dependent nephrotic syndrome than the steroid-sensitive nephrotic syndrome patients (P = 0.018; odds ratio = 1.76).

Conclusion

Our data suggests that genetic variations in CAT were unlikely to confer susceptibility to INS in Chinese children, whereas the C allele of the CAT rs769217 polymorphism showed a strong association with steroid-dependent responses in Chinese INS children.
The cold gas and dust properties of red star-forming galaxies
Authors: Chown Ryan , Parker Laura , Wilson Christine D , Brown Toby , Evans Fraser , Gao Yang , Hwang Ho Seong , Lin Lihwai , Saintonge Amelie , Sargent Mark , Smith Matthew , Xiao Ting
Published: August 2022

We study the cold gas and dust properties for a sample of red star-forming galaxies called ‘red misfits.’ We collect single-dish CO observations and H i observations from representative samples of low-redshift galaxies, as well as our own James Clerk Maxwell Telescope CO observations of red misfits. We also obtain SCUBA-2 850 $\mu$m observations for a subset of these galaxies. With these data we compare the molecular gas, total cold gas, and dust properties of red misfits against those of their blue counterparts (‘blue actives’) taking non-detections into account using a survival analysis technique. We compare these properties at fixed position in the log SFR–log M⋆ plane, as well as versus offset from the star-forming main sequence. Compared to blue actives, red misfits have slightly longer molecular gas depletion times, similar total gas depletion times, significantly lower molecular- and total-gas mass fractions, lower dust-to-stellar mass ratios, similar dust-to-gas ratios, and a significantly flatter slope in the log Mmol–log M⋆ plane. Our results suggest that red misfits as a population are likely quenching due to a shortage in gas supply.
VLT/UVES observation of the outflow in quasar SDSS J1439-0106
Authors: Byun Doyee , Arav Nahum , Walker Andrew
Published: August 2022

We analyse the VLT/UVES spectrum of the quasar SDSS J143907.5-010616.7, retrieved from the UVES Spectral Quasar Absorption Database. We identify two outflow systems in the spectrum: a mini broad absorption line (mini-BAL) system and a narrow absorption line (NAL) system. We measure the ionic column densities of the mini-BAL ($v$ = −1550 km s−1) outflow, which has excited state absorption troughs of ${\rm Fe\, \rm {\small {ii}}}$. We determine that the electron number density $\log {n_e}=3.4^{+0.1}_{-0.1}$, based on the ratios between the excited and ground state abundances of ${\rm Fe\, \rm {\small {ii}}}$, and find the kinetic luminosity of the outflow to be ${\lesssim}0.1\,\hbox{per cent}$ of the quasar’s Eddington luminosity, making it insufficient to contribute to AGN feedback.
Active galactic nuclei signatures in Red Geyser galaxies from Gemini GMOS-IFU observations
Authors: Ilha Gabriele S , Riffel Rogemar A , Ricci Tiago V , Rembold Sandro B , Storchi-Bergmann Thaisa , Riffel Rogério , Roy Namrata , Bundy Kevin , Nemmen Rodrigo , Schimoia Jáderson S , da Costa Luiz N
Published: August 2022

Red Geysers are quiescent galaxies with galactic scale ionized outflows, likely due to low-luminosity active galactic nuclei (AGN). We used Gemini GMOS-IFU observations of the inner ∼1–3 kpc of nine Red Geysers selected from the MaNGA survey to study the gas ionization and kinematics. The emission-line ratios suggest the presence of Seyfert/LINER (Low Ionization Nuclear Emission Region) nuclei in all sources. Two galaxies show  Hα equivalent width ( Hα EW) larger than 3 Å (indicative of AGN ionization) within an aperture 2 ${_{.}^{\prime\prime}}$5 of diameter (1.3–3.7 kpc at the distance of galaxies) for MaNGA data, while with the higher resolution GMOS data, four galaxies present  Hα EW>3 Å within an aperture equal to the angular resolution (0.3–0.9 kpc). For two objects with GMOS-IFU data, the  Hα EW is lower than 3 Å but larger than 1.5 Å, most probably due to a faint AGN. The spatially resolved electron density maps show values between 100 and 3000 cm −3 and are consistent with those determined in other studies. The large (MaNGA) and the nuclear scale (GMOS-IFU) gas velocity fields are misaligned, with a kinematic position angle difference between 12° and 60°. The [N ii] λ6583 emission-line profiles are asymmetrical, with blue wings on the redshifted side of the velocity field and red wings on the blueshifted side. Our results support previous indications that the gas in Red Geysers is ionized by an AGN, at least in their central region, with the presence of outflows, likely originating in a precessing accretion disc.
Core-collapse supernovae in dense environments – particle acceleration and non-thermal emission
Authors: Brose R , Sushch I , Mackey J
Published: August 2022

Supernova remnants (SNRs) are known to accelerate cosmic rays from the detection of non-thermal emission in radio waves, X-rays, and gamma-rays. However, the ability to accelerate cosmic rays up to PeV energies has yet to be demonstrated. The presence of cut-offs in the gamma-ray spectra of several young SNRs led to the idea that PeV energies might only be achieved during the first years of a remnant’s evolution. We use our time-dependent acceleration-code RATPaC to study the acceleration of cosmic rays in supernovae expanding into dense environments around massive stars. We performed spherically symmetric one-dimensional (1D) simulations in which we simultaneously solve the transport equations for cosmic rays, magnetic turbulence, and the hydrodynamical flow of the thermal plasma in the test-particle limit. We investigated typical circumstellar-medium (CSM) parameters expected around red supergiant (RSG) and luminous blue variable (LBV) stars for freely expanding winds and accounted for the strong γγ absorption in the first days after explosion. The maximum achievable particle energy is limited to below $600\,$TeV even for the largest considered values of the magnetic field and mass-loss rates. The maximum energy is not expected to surpass $\approx 200\,$ and $\approx 70\,$TeV for LBVs and RSGs that experience moderate mass-loss prior to the explosion. We find gamma-ray peak-luminosities consistent with current upper limits and evaluate that current-generation instruments are able to detect the gamma-rays from Type-IIP explosions at distances up to $\approx 60\,$ kpc and Type-IIn explosions up to $\approx 1.0\,$ Mpc. We also find a good agreement between the thermal X-ray and radio synchrotron emission predicted by our models with a range of observations.
Did a close tidal encounter cause the Great Dimming of Betelgeuse?
Authors: Aronson Hailey , Baumgarte Thomas W , Shapiro Stuart L
Published: August 2022

We assess whether gravity darkening, induced by a tidal interaction during a stellar fly-by, might be sufficient to explain the Great Dimming of Betelgeuse. Adopting several simple approximations, we calculate the tidal deformation and associated gravity darkening in a close tidal encounter, as well as the reduction in the radiation flux as seen by a distant observer. We show that, in principle, the duration and degree of the resulting stellar dimming can be used to estimate the minimum pericentre separation and mass of a fly-by object, which, even if it remains undetected otherwise, might be a black hole, neutron star, or white dwarf. Our estimates show that, while such fly-by events may occur in other astrophysical scenarios, where our analysis should be applicable, they likely are not large enough to explain the Great Dimming of Betelgeuse by themselves.
Analytic models of dust temperature in high-redshift galaxies
Authors: Hirashita Hiroyuki , Chiang I-Da
Published: August 2022

We investigate physical reasons for high-dust temperatures (Tdust ≳ 40K) observed in some high-redshift ($z$ > 5) galaxies using analytic models. We consider two models that can be treated analytically: the radiative transfer (RT) model, where a broad distribution of values for Tdust is considered, and the one-tempearture (one-T) model, which assumes uniform Tdust. These two extremes serve to bracket the most realistic scenario. We adopt the Kennicutt–Schmidt (KS) law to relate stellar radiation field to gas surface density, and vary the dust-to-gas ratio. As a consequence, our model is capable of predicting the relation between the surface density of star formation rate (ΣSFR) or dust mass (Σdust) and Tdust. We show that the high Tdust observed at $z$ ≳ 5 favour low dust-to-gas ratios (≲ 10−3). An enhanced star formation compared with the KS law gives an alternative explanation for the high Tdust. The dust temperatures are similar between the two (RT and one-T) models as long as we use ALMA Bands 6–8. We also examine the relation among ΣSFR, Σdust, and Tdust without assuming the KS law, and confirm the consistency with the actual observational data at $z$ > 5. In the one-T model, we also examine a clumpy dust distribution, which predicts lower Tdust because of the leakage of stellar radiation. This enhances the requirement of low-dust abundance or high-star formation efficiency to explain the observed high Tdust.
Three-dimensional structure of the central molecular zone
Authors: Sofue Yoshiaki
Published: August 2022

A detailed comparison of H i and CO line cube data of the Galactic Centre (GC) region from the archives is obtained. The central molecular zone (CMZ) is shown to be embedded in the H i disc (central H i zone, CHZ) of radius ∼320 pc and vertical scale height ∼70 pc. A radio continuum belt is shown to run parallel to molecular Arms I and II. The belt draws a double infinity (∞∞) on the sky, connecting Sgr E (l ∼ −1${_{.}^{\circ}}$2), C, B1, B2, and Sgr D (+1${_{.}^{\circ}}$2), and is interpreted as a warping star-forming ring. The molecular Arms are closely associated with the H i arms on the longitude-velocity diagram (LVD), showing coherent rigid-body ridges. Due to the close relationship between H i and CO, the H i line absorption can be used to determine the Arms’ position relative to Sgr A, B1, B2, and C. Combining the trigonometric data of proper motions of Sgr A* and maser sources of Sgr B2 as well as radial velocities, the 3D velocity vector of Sgr B2 is determined. From these analyses, the molecular Arm I with Sgr B2 is shown to be located in the near side of Sgr A*, and Arm II with Sgr C in the other side, both composing a pair of symmetrical Arms around the GC. We present a possible 3D view of Sgr A through E and Arms I and II along with a parameter list.
Characterizing the daytime sextantids meteor shower and unveiling the nature of the phaethon-geminid stream complex
Authors: Kipreos Y , Campbell-Brown Margaret , Brown P , Vida D
Published: August 2022

The Daytime Sextantids meteor shower, part of the Phaethon-Geminid Stream Complex (PGC), is closely related to the Geminids, currently the strongest meteor shower visible at the Earth. The Daytime Sextantids (DSX) share a similar orbit to asteroid 2005 UD, but the nature of the association remains unclear. From optical data we find that DSX meteors ablate similarly to Geminids, suggesting that they are also high density and consistent with a common origin. From radar data we have isolated 19 007 DSX orbits through application of a novel convex hull approach to determine stream membership. We find at the peak the mean semimajor axis is near 1 au, eccentricity is 0.86 and that both decrease as a function of solar longitude. The inclination averages 25 deg at the peak but increases over time. Noticeable DSX activity extends from solar longitude 173–196° with a flux plateau between 186 and 189°. The peak flux is 2 ± 0.05 × 10−3 km−2 hr−1, equivalent to a ZHR of 20. We estimate a true differential mass index for the shower of s = 1.64 ± 0.06 at the time of peak and an average of 1.70 ± 0.07 for days surrounding the peak. The mass of the DSX stream is estimated to be 1016 g, the same order as 2005 UD, suggesting the stream is too massive to have been created by recent meteoroid production from 2005 UD. We propose that the DSX and 2005 UD were created in the same break-up event that created 3200 Phaethon.
Nature of helicity injection in non-erupting solar active regions
Authors: Vemareddy P
Published: August 2022

Using time-sequence vector magnetic field and coronal observations from Solar Dynamics Observatory, we report the observations of the magnetic field evolution and coronal activity in four emerging active regions (ARs). The ARs emerge with leading polarity being the same as for the majority of ARs in a hemisphere of solar cycle 24. After emergence, the magnetic polarities separate each other without building a sheared polarity inversion line. In all four ARs, the magnetic fields are driven by foot point motions such that the sign of the helicity injection (dH/dt) in the first half of the evolution is changed to the opposite sign in the later part of the observation time. This successive injection of opposite helicity is also consistent with the sign of mean force–free twist parameter (αav). Further, the EUV light curves off the ARs in 94 Å and GOES X-ray flux reveal flaring activity below C-class magnitude. Importantly, the white-light coronagraph images in conjunction with the AR images in Atmospheric Imaging Assembly (AIA) 94 Å delineate the absence of associated Coronal Mass ejections (CMEs) with the studied ARs. These observations imply that the ARs with successive injection of opposite sign magnetic helicity are not favourable to twisted flux rope formation with excess coronal helicity, and therefore are unable to launch CMEs, according to recent reports. This study provides the characteristics of helicity flux evolution in the ARs referring to the conservative property of magnetic helicity and more such studies would help to quantify the eruptive capability of a given AR.
The complex stellar system M 22: confirming abundance variations with high precision differential measurements
Authors: McKenzie M , Yong D , Marino A F , Monty S , Wang E , Karakas A I , Milone A P , Legnardi M V , Roederer I U , Martell S , Horta D
Published: August 2022

M 22 (NGC 6656) is a chemically complex globular cluster-like system reported to harbour heavy element abundance variations. However, the extent of these variations and the origin of this cluster is still debated. In this work, we investigate the chemical in-homogeneity of M 22 using differential line-by-line analysis of high-quality (R = 110 000, S/N  = 300 per pixel at 514 nm) VLT/UVES spectra of six carefully chosen red giant branch stars. By achieving abundance uncertainties as low as ∼0.01 dex (∼2 per cent), this high precision data validates the results of previous studies and reveals variations in Fe, Na, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Y, Zr, La, Ce, Nd, Sm, and Eu. Additionally, we can confirm that the cluster hosts two stellar populations with a spread of at least 0.24 dex in [Fe/H] and an average s-process abundance spread of 0.65 dex. In addition to global variations across the cluster, we also find non-negligible variations within each of the two populations, with the more metal-poor population hosting larger spreads in elements heavier than Fe than the metal-rich. We address previous works that do not identify anomalous abundances and relate our findings to our current dynamical understanding of the cluster. Given our results, we suggest that M 22 is either a nuclear star cluster, the product of two merged clusters, or an original building block of the Milky Way.
Probing dark matter with strong gravitational lensing through an effective density slope
Authors: Şengül Atinç Çagan , Dvorkin Cora
Published: August 2022

Many dark matter (DM) models that are consistent with current cosmological data show differences in the predicted (sub)halo mass function, especially at sub-galactic scales, where observations are challenging due to the inefficiency of star formation. Strong gravitational lensing has been shown to be a useful tool for detecting dark low-mass (sub)haloes through perturbations in lensing arcs, therefore allowing the testing of different DM scenarios. However, measuring the total mass of a perturber from strong lensing data is challenging. Overestimating or underestimating perturber masses can lead to incorrect inferences about the nature of DM. In this paper, we argue that inferring an effective slope of the DM density profile, which is the power-law slope of perturbers at intermediate radii, where we expect the perturber to have the largest observable effect, is a promising way to circumvent these challenges. Using N-body simulations, we show that (sub)halo populations under different DM scenarios differ in their effective density slope distributions. Using realistic mocks of Hubble Space Telescope observations of strong lensing images, we show that the effective density slope of perturbers can be robustly measured with high enough accuracy to discern between different models. We also present our measurement of the effective density slope $\gamma =1.96\substack{+0.12 \\ -0.12}$ for the perturber in JVAS B1938+666, which is a 2σ outlier of the cold DM scenario. More measurements of this kind are needed to draw robust conclusions about the nature of DM.
Dwarf AGNs from Optical Variability for the Origins of Seeds (DAVOS): insights from the dark energy survey deep fields
Authors: Burke Colin J , Liu Xin , Shen Yue , Phadke Kedar A , Yang Qian , Hartley Will G , Harrison Ian , Palmese Antonella , Guo Hengxiao , Zhang Kaiwen , Kron Richard , Turner David J , Giles Paul A , Lidman Christopher , Chen Yu-Ching , Gruendl Robert A , Choi Ami , Amon Alexandra , Sheldon Erin , Aguena M , Allam S , Andrade-Oliveira F , Bacon D , Bertin E , Brooks D , Rosell A Carnero , Kind M Carrasco , Carretero J , Conselice C , Costanzi M , da Costa L N , Pereira M E S , Davis T M , De Vicente J , Desai S , Diehl H T , Everett S , Ferrero I , Flaugher B , García-Bellido J , Gaztanaga E , Gruen D , Gschwend J , Gutierrez G , Hinton S R , Hollowood D L , Honscheid K , Hoyle B , James D J , Kuehn K , Maia M A G , Marshall J L , Menanteau F , Miquel R , Morgan R , Paz-Chinchón F , Pieres A , Malagón A A Plazas , Reil K , Romer A K , Sanchez E , Schubnell M , Serrano S , Sevilla-Noarbe I , Smith M , Suchyta E , Tarle G , Thomas D , To C , Varga T N , Wilkinson R D ,   (DES Collaboration)
Published: August 2022

We present a sample of 706, z < 1.5 active galactic nuclei (AGNs) selected from optical photometric variability in three of the Dark Energy Survey (DES) deep fields (E2, C3, and X3) over an area of 4.64 deg2. We construct light curves using difference imaging aperture photometry for resolved sources and non-difference imaging PSF photometry for unresolved sources, respectively, and characterize the variability significance. Our DES light curves have a mean cadence of 7 d, a 6-yr baseline, and a single-epoch imaging depth of up to g ∼ 24.5. Using spectral energy distribution (SED) fitting, we find 26 out of total 706 variable galaxies are consistent with dwarf galaxies with a reliable stellar mass estimate ($M_{\ast }\lt 10^{9.5}\, {\rm M}_\odot$; median photometric redshift of 0.9). We were able to constrain rapid characteristic variability time-scales (∼ weeks) using the DES light curves in 15 dwarf AGN candidates (a subset of our variable AGN candidates) at a median photometric redshift of 0.4. This rapid variability is consistent with their low black hole (BH) masses. We confirm the low-mass AGN nature of one source with a high S/N optical spectrum. We publish our catalogue, optical light curves, and supplementary data, such as X-ray properties and optical spectra, when available. We measure a variable AGN fraction versus stellar mass and compare to results from a forward model. This work demonstrates the feasibility of optical variability to identify AGNs with lower BH masses in deep fields, which may be more ‘pristine’ analogues of supermassive BH seeds.
Observational window effects on multi-object reverberation mapping
Authors: Malik Umang , Sharp Rob , Martini Paul , Davis Tamara M , Tucker Brad E , Yu Zhefu , Penton Andrew , Lewis Geraint F , Calcino Josh
Published: August 2022

Contemporary reverberation mapping campaigns are employing wide-area photometric data and high-multiplex spectroscopy to efficiently monitor hundreds of active galactic nuclei (AGNs). However, the interaction of the window function(s) imposed by the observation cadence with the reverberation lag and AGN variability time-scales (intrinsic to each source over a range of luminosities) impact our ability to recover these fundamental physical properties. Time dilation effects due to the sample source redshift distribution introduce added complexity. We present comprehensive analysis of the implications of observational cadence, seasonal gaps, and campaign baseline duration (i.e. the survey window function) for reverberation lag recovery. We find that the presence of a significant seasonal gap dominates the efficacy of any given campaign strategy for lag recovery across the parameter space, particularly for those sources with observed-frame lags above 100 d. Using the Australian Dark Energy Survey as a baseline, we consider the implications of this analysis for the 4MOST/Time-Domain Extragalactic Survey campaign providing concurrent follow-up of the Legacy Survey of Space and Time deep-drilling fields, as well as upcoming programmes. We conclude that the success of such surveys will be critically limited by the seasonal visibility of some potential field choices, but show significant improvement from extending the baseline. Optimizing the sample selection to fit the window function will improve survey efficacy.
Pulsar radio emission mechanism – II. On the origin of relativistic Langmuir solitons in pulsar plasma
Authors: Rahaman Sk Minhajur , Mitra Dipanjan , Melikidze George I , Lakoba Taras
Published: August 2022

Observations suggest that coherent radio emission from pulsars is excited in a dense pulsar plasma by curvature radiation from charge bunches. Numerous studies propose that these charge bunches are relativistic charge solitons that are solutions of the non-linear Schrödinger equation (NLSE) with a group velocity dispersion (G), cubic non-linearity (q), and non-linear Landau damping (s). The formation of stable solitons crucially depends on the parameters G, q, and s as well as the particle distribution function (DF). In this work, we use realistic pulsar plasma parameters obtained from observational constraints to explore the parameter space of NLSE for two representative DFs of particles’ momenta: Lorentzian (long-tailed) and Gaussian (short-tailed). The choice of DFs critically affects the value of |s/q|, which, in turn, determines whether solitons can form. Numerical simulations show that well-formed solitons are obtained only for small values of |s/q| ≲ 0.1, while for moderate and higher values of |s/q| ≳ 0.5 soliton formation is suppressed. Small values for |s/q| ∼ 0.1 are readily obtained for long-tailed DF for a wide range of plasma temperatures. On the other hand, short-tailed DF provides these values only for some narrow range of plasma parameters. Thus, the presence of a prominent high-energy tail in the particle DF favours soliton formation for a wide range of plasma parameters. Besides pair plasma, we also include an iron ion component and find that they make a negligible contribution in either modifying the NLSE coefficients or contributing to charge separation.
Detailed study of extended γ-ray morphology in the vicinity of the Coma cluster with Fermi Large Area Telescope
Authors: Baghmanyan Vardan , Zargaryan Davit , Aharonian Felix , Yang Ruizhi , Casanova Sabrina , Mackey Jonathan
Published: August 2022

Galaxy clusters can be sources of high-energy (HE) γ-ray radiation due to the efficient acceleration of particles exceeding EeV energies. At present, though, the only candidate for emitting HE γ-rays is the Coma cluster, towards which an excess of γ-ray emission has been detected by the Fermi Large Area Telescope (Fermi-LAT). Using ∼12.3 yr of Fermi-LAT data, we explored the region of the Coma cluster between energies 100 MeV and 1 TeV by detailed spectral and morphological analysis. In the region of the Coma cluster, we detected diffuse γ-ray emission of energies between 100 MeV and 1 TeV with a 5.4σ extension significance and a 68 per cent containment radius of $0.82^{+0.10}_{-0.05}$ degrees derived with a two-dimensional homogeneous disc model. The corresponding γ-ray spectrum extends up to ∼50 GeV, with a power-law index of Γ = 2.23 ± 0.11 and flux of $\mathrm{(3.84\pm 0.67)\times 10^{-12}\, erg\, cm^{-2}\, s^{-1}}$. Using energy arguments we show that point-like sources such as radiogalaxies and star-forming galaxies are unlikely to explain the emission, and more likely, the emission is produced in the Coma cluster. Besides, we also identified three point-like sources in the region. However, because of limited statistics, we could neither exclude nor confirm the contribution of three point-like sources to the total emissions.
The effect of ionizing background fluctuations on the spatial correlations of high redshift Lyα-emitting galaxies
Authors: Meiksin Avery , Suarez Teresita
Published: August 2022

We investigate the possible influence of fluctuations in the metagalactic photoionizing ultraviolet background (UVBG) on the clustering of Lyα-emitting galaxies through the modulation of the ionization level of the gas surrounding the systems. At redshift z > 5, even when assuming the reionization of the intergalactic medium has completed, the fluctuations are sufficiently large that they may non-negligibly enhance, and possibly even dominate, the angular correlation function on scales up to a few hundred arcsecs. Whilst a comparison with observations at z ≃ 5.7 is statistically consistent with no influence of UVBG fluctuations, allowing for the fluctuations opens up the range of acceptable models to include those with relatively low bias factors for the Lyα-emitting galaxies. In this case, the evolution in the bias factor of Lyα-emitters over the approximate redshift range 3 < z < 7 corresponds to a nearly constant halo mass for Lyα-emitting galaxies of ∼1010.5 M⊙.
Estimating sizes of type-2 AGN narrow-line regions from multiple survey spectra – a demonstration
Authors: Zhang Xue-Guang , Zhao YuanBo
Published: August 2022

In the Letter, an interesting method is proposed to estimate size of narrow emission-lines regions (NLRs) of a type-2 AGN SDSS J083823.91 + 490241.1 (=SDSS J0838) at a redshift of 0.101, by comparing spectroscopic properties through the SDSS fibre (MJD = 51873) (diameter of 3 arcsec) and through the eBOSS fibre (MJD = 55277) (diameter of 2 arcsec). After subtractions of ppxf method determined host galaxy contributions, the narrow emission lines of SDSS J0838 in the SDSS spectrum and in the eBOSS spectrum can be well measured by Gaussian functions, leading more than 90 per cent of [O iii] emissions to be covered by the eBOSS fibre with diameter of 2 arcsec. Meanwhile, both none broad emission components and none-variabilities of ZTF 3 yr-long g-/r-band light curves can be applied to confirm SDSS J0838 as a type-2 AGN, indicating few orientation effects on the projected NLRs size in SDSS J0838. Therefore, upper limit about 1 arcsec (2250 pc) of the NLRs size can be reasonably accepted in SDSS J0838. Combining with the intrinsic reddening corrected [O iii] line luminosity, the upper limit of NLRs size in SDSS J0838 well lies within the 99.9999 per cent confidence bands of the R-L empirical relation for NLRs in AGN.
Information content of BP/RP spectra in Gaia DR3
Authors: Witten Callum E C , Aguado David S , Sanders Jason L , Belokurov Vasily , Evans N Wyn , Koposov Sergey E , Allende Prieto Carlos , De Angeli Francesca , Irwin Mike J
Published: August 2022

Gaia Data Release 3 has provided the astronomical community with the largest stellar spectroscopic survey to date (> 220 million sources). The low resolution (R∼50) blue photometer (BP) and red photometer (RP) spectra will allow for the estimation of stellar atmospheric parameters such as effective temperature, surface gravity, and metallicity. We create mock Gaia BP/RP spectra and use Fisher information matrices to probe the resolution limit of stellar parameter measurements using BP/RP spectra. The best-case scenario uncertainties that this analysis provides are then used to produce a mock-observed stellar population in order to evaluate the false positive rate (FPR) of identifying extremely metal-poor stars. We conclude that the community will be able to confidently identify metal-poor stars at magnitudes brighter than G = 16 using BP/RP spectra. At fainter magnitudes true detections will start to be overwhelmed by false positives. When adopting the commonly-used G < 14 limit for metal-poor star searches, we find a FPR for the low-metallicity regimes [Fe/H] < -2, -2.5, and -3 of just 14 ${{\ \rm per\ cent}}$, 33 ${{\ \rm per\ cent}}$, and 56 ${{\ \rm per\ cent}}$ respectively, offering the potential for significant improvements on previous targeting campaigns. Additionally, we explore the chemical sensitivity obtainable directly from BP/RP spectra for carbon and α-elements. We find an absolute carbon abundance uncertainty of σA(C) < 1 dex for carbon-enriched metal-poor (CEMP) stars, indicating the potential to identify a CEMP stellar population for follow-up confirmation with higher resolution spectroscopy. Finally, we find that large uncertainties in α-element abundance measurements using BP/RP spectra means that efficiently obtaining these abundances will be challenging.
The discovery and characterization of (594913) 'Ayló'chaxnim, a kilometre sized asteroid inside the orbit of Venus
Authors: Bolin Bryce T , Ahumada T , van Dokkum P , Fremling C , Granvik M , Hardegree-Ullman K K , Harikane Y , Purdum J N , Serabyn E , Southworth J , Zhai C
Published: August 2022

Near-Earth asteroid population models predict the existence of bodies located inside the orbit of Venus. Despite searches up to the end of 2019, none had been found. We report discovery and follow-up observations of (594913) 'Ayló'chaxnim, an asteroid with an orbit entirely interior to Venus. (594913) 'Ayló'chaxnim has an aphelion distance of ∼0.65 au, is ∼2 km in diameter and is red in colour. The detection of such a large asteroid inside the orbit of Venus is surprising given their rarity according to near-Earth asteroid population models. As the first officially numbered and named asteroid located entirely within the orbit of Venus, we propose that the class of interior to Venus asteroids be referred to as 'Ayló'chaxnim asteroids.
Neuromorphic-computing-based adaptive learning using ion dynamics in flexible energy storage devices
Authors: Zhao Shufang , Ran Wenhao , Lou Zheng , Li Linlin , Poddar Swapnadeep , Wang Lili , Fan Zhiyong , Shen Guozhen
Published: August 2022

High-accuracy neuromorphic devices with adaptive weight adjustment are crucial for high-performance computing. However, limited studies have been conducted on achieving selective and linear synaptic weight updates without changing electrical pulses. Herein, we propose high-accuracy and self-adaptive artificial synapses based on tunable and flexible MXene energy storage devices. These synapses can be adjusted adaptively depending on the stored weight value to mitigate time and energy loss resulting from recalculation. The resistance can be used to effectively regulate the accumulation and dissipation of ions in single devices, without changing the external pulse stimulation or preprogramming, to ensure selective and linear synaptic weight updates. The feasibility of the proposed neural network based on the synapses of flexible energy devices was investigated through training and machine learning. The results indicated that the device achieved a recognition accuracy of ∼95% for various neural network calculation tasks such as numeric classification.
Spectral break of energetic pulsar wind nebulae detected with wideband X-ray observations
Authors: Bamba Aya , Shibata Shinpei , Tanaka Shuta J , Mori Koji , Uchida Hiroyuki , Terada Yukikatsu , Ishizaki Wataru
Published: August 2022

Pulsar wind nebulae (PWNe) are one of the most energetic galactic sources with bright emissions from radio waves to very high-energy gamma-rays. We perform wideband X-ray spectroscopy of four energetic PWNe, N 157 B, PSR J1813−1749, PSR J1400−6325, and G21.5−0.9, with the Suzaku, Chandra, NuSTAR, and Hitomi observatories. A significant spectral break or cut-off feature is found in the hard X-ray band for all the samples, except for N 157 B. The break energies in the broken power-law fitting are in the range of 4–14 keV, whereas the cut-off energies in the cut-off power-law fitting are at 22 keV or higher. The break or cut-off energy does not show a significant correlation with either the spin-down energy or characteristic age of the hosting pulsars. A possible correlation is found between the photon index change in the broken power-law fitting and the X-ray emitting efficiency of the pulsars, although its significance is not high enough to be conclusive. We discuss what determines the break parameters based on simple models.
Combining ex-ante and ex-post assessments to support the sustainable transformation of agriculture: The case of Swiss pesticide-free wheat production
Authors: Möhring Niklas , Huber Robert , Finger Robert
Published: August 2022

Sustainable intensification of agriculture requires the adoption of new production techniques, tools, and programmes on a large scale. This implies substantial shifts in established ways of farming under uncertain information about potential economic and environmental outcomes. Research can support stakeholders such as farmers, industry, and policy in this transformation by providing evidence-based information. The provision of such information can be improved by combining ex-ante and ex-post assessment tools at different stages of policy cycles and projects. We here present a unique combination of ex-ante bio-economic modelling analysis and ex-post econometric analyses based on survey data using the example of a novel pesticide-free wheat production programme in Switzerland. We exemplify how ex-ante and ex-post evaluation can be combined to increase the robustness of results for stakeholders, e.g. on yield losses from pesticide-free production or farmer typologies important for adoption. Further, we show how their alignment can improve future assessments in project and policy cycles, e.g. through the choice of suitable variables explaining farmer decision-making and priors on the distribution of their characteristics. Despite the identified synergies between assessments, we also find that their integration is limited by the timing and information requirements of stakeholders at different stages in the project. Finally, potential synergies in our case study strongly depended on the type of ex-ante models chosen for evaluation and their alignment with ex-post methods. Especially integrating farmer behaviour in ex-ante assessments seems to be crucial to arriving at holistic evaluations of large-scale programmes for sustainable agricultural practices and providing useful information to stakeholders.