bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma and cerebrospinal fluid concentrations of cefiderocol during successful treatment of carbapenem-resistant Acinetobacter baumannii meningitis
Authors: Kufel Wesley D , Abouelhassan Yasmeen , Steele Jeffrey M , Gutierrez Ramiro L , Perwez Talha , Bourdages George , Nicolau David P
Published: July 2022

Background

To date, no real-world data are available to describe cefiderocol use in carbapenem-resistant Acinetobacter baumannii (CRAB) meningitis. Furthermore, cefiderocol pharmacokinetic (PK) data to support CNS penetration in human subjects are limited. These gaps pose a significant concern for clinicians who are faced with treating such infections when considering cefiderocol use.

Objectives

To describe cefiderocol CSF and plasma PK and pharmacodynamic (PD) data from two different dosing regimens [2 g IV q6h (regimen 1) and 2 g IV q8h (regimen 2)] during treatment of CRAB meningitis.

Patients and methods

A 61-year-old woman with CRAB meningitis was treated with cefiderocol and intraventricular gentamicin. Steady-state plasma and CSF cefiderocol concentrations were evaluated on Day 19 (regimen 1) and Day 24 (regimen 2) during the cefiderocol treatment course.

Results

CSF AUC was 146.49 and 118.28 mg·h/L, as determined by the linear-log trapezoidal method for regimens 1 and 2, respectively. Penetration into CSF estimated as the AUCCSF/AUCfree plasma ratio was 68% and 60% for regimens 1 and 2, respectively. Estimated free plasma and CSF concentrations exceeded the MIC of the isolate for 100% of the dosing interval. Microbiological and clinical cure were achieved, and no cefiderocol-associated adverse effects were observed.

Conclusions

Cefiderocol, when given as 2 g q8h and 2 g q6h, attained CSF concentrations that exceeded the organism-specific MIC and the CLSI susceptible breakpoint (≤4 mg/L) for 100% of the dosing interval.
Identifying infected patients using semi-supervised and transfer learning
Authors: Bashiri Fereshteh S , Caskey John R , Mayampurath Anoop , Dussault Nicole , Dumanian Jay , Bhavani Sivasubramanium V , Carey Kyle A , Gilbert Emily R , Winslow Christopher J , Shah Nirav S , Edelson Dana P , Afshar Majid , Churpek Matthew M
Published: July 2022

Objectives

Early identification of infection improves outcomes, but developing models for early identification requires determining infection status with manual chart review, limiting sample size. Therefore, we aimed to compare semi-supervised and transfer learning algorithms with algorithms based solely on manual chart review for identifying infection in hospitalized patients.

Materials and Methods

This multicenter retrospective study of admissions to 6 hospitals included “gold-standard” labels of infection from manual chart review and “silver-standard” labels from nonchart-reviewed patients using the Sepsis-3 infection criteria based on antibiotic and culture orders. “Gold-standard” labeled admissions were randomly allocated to training (70%) and testing (30%) datasets. Using patient characteristics, vital signs, and laboratory data from the first 24 hours of admission, we derived deep learning and non-deep learning models using transfer learning and semi-supervised methods. Performance was compared in the gold-standard test set using discrimination and calibration metrics.

Results

The study comprised 432 965 admissions, of which 2724 underwent chart review. In the test set, deep learning and non-deep learning approaches had similar discrimination (area under the receiver operating characteristic curve of 0.82). Semi-supervised and transfer learning approaches did not improve discrimination over models fit using only silver- or gold-standard data. Transfer learning had the best calibration (unreliability index P value: .997, Brier score: 0.173), followed by self-learning gradient boosted machine (P value: .67, Brier score: 0.170).

Discussion

Deep learning and non-deep learning models performed similarly for identifying infection, as did models developed using Sepsis-3 and manual chart review labels.

Conclusion

In a multicenter study of almost 3000 chart-reviewed patients, semi-supervised and transfer learning models showed similar performance for model discrimination as baseline XGBoost, while transfer learning improved calibration.
European Firm Concentration and Aggregate Productivity
Authors: Bighelli Tommaso , di Mauro Filippo , Melitz Marc J , Mertens Matthias
Published: July 2022

This paper derives a European Herfindahl–Hirschman concentration index from 15 micro-aggregated country datasets. In the last decade, European concentration rose due to a reallocation of economic activity toward large and concentrated industries. Over the same period, productivity gains from an increasing allocative efficiency of the European market accounted for 50% of European productivity growth while markups stayed constant. Using country-industry variation, we show that changes in concentration are positively associated with changes in productivity and allocative efficiency. This holds across most sectors and countries and supports the notion that rising concentration in Europe reflects a more efficient market environment rather than weak competition and rising market power.
Estimation and Inference of Quantile Impulse Response Functions by Local Projections: With Applications to VaR Dynamics
Authors: Han Heejoon , Jung Whayoung , Lee Ji Hyung
Published: July 2022

This article investigates the estimation and inference of quantile impulse response functions. We propose a new estimation method using the idea of local projections by Jordà (2005). We establish consistency and asymptotic normality of the estimator, thereby enabling asymptotic inference. We also consider the confidence interval construction based on the stationary bootstrap and prove its consistency. Confirmatory simulation results and empirical practices on value-at-risk dynamics are provided.
AIM-CICs: an automatic identification method for cell-in-cell structures based on convolutional neural network
Authors: Tang Meng , Su Yan , Zhao Wei , Niu Zubiao , Ruan Banzhan , Li Qinqin , Zheng You , Wang Chenxi , Zhang Bo , Zhou Fuxiang , Wang Xiaoning , Huang Hongyan , Shi Hanping , Sun Qiang
Published: July 2022

Whereas biochemical markers are available for most types of cell death, current studies on non-autonomous cell death by entosis rely strictly on the identification of cell-in-cell structures (CICs), a unique morphological readout that can only be quantified manually at present. Moreover, the manual CIC quantification is generally over-simplified as CIC counts, which represents a major hurdle against profound mechanistic investigations. In this study, we take advantage of artificial intelligence technology to develop an automatic identification method for CICs (AIM-CICs), which performs comprehensive CIC analysis in an automated and efficient way. The AIM-CICs, developed on the algorithm of convolutional neural network, can not only differentiate between CICs and non-CICs (the area under the receiver operating characteristic curve (AUC) > 0.99), but also accurately categorize CICs into five subclasses based on CIC stages and cell number involved (AUC > 0.97 for all subclasses). The application of AIM-CICs would systemically fuel research on CIC-mediated cell death, such as high-throughput screening.
Diversity and Prevalence of Ectoparasites on Poultry from Open Environment Farms in the Western-United States of Washington, Idaho, Oregon, and California
Authors: Chambless Kendra N , Cornell Kevin A , Crespo Rocio , Snyder William E , Owen Jeb P
Published: July 2022

Open-environment poultry farms that allow chickens to forage outdoors are becoming increasingly common throughout the United States and Europe; however, there is little information regarding the diversity and prevalence of ectoparasites in these farming systems. Eight to 25 birds were captured and surveyed for ectoparasites on each of 17 farms across the states of Washington, Idaho, Oregon, and California. Among the farms sampled, six louse species (Phthiraptera: Ischnocera & Amblycera) and two parasitic mite species (Acari: Mesostigmata) were collected and identified: Goniodes gigas (Taschenberg, 1879; Phthiraptera: Menoponidae) on one farm, Menacathus cornutus (Schömmer, 1913; Phthiraptera: Menoponidae) on one farm, Menopon gallinae (Linnaeus, 1758; Phthiraptera: Menoponidae) on six farms, Lipeurus caponis (Linnaeus, 1758; Phthiraptera: Philopteridae) on five farms, Menacanthus stramineus (Nitzsch, 1818; Phthiraptera: Menoponidae) on nine farms, Goniocotes gallinae De Geer (Phthiraptera: Philopteridae) on 11 farms, Dermanyssus gallinae (De Geer, 1778; Mesostigmata: Dermanyssidae) on two farms, and Ornithonyssus sylviarum (Canestrini & Fanzago, 1877; Mesostigmata: Macronyssidae) on one farm. The diversity of ectoparasites on these open environment poultry farms highlights a need for additional research on ectoparasite prevalence and intensity in these poultry farming systems.
Life History Data ofDipetalogaster maxima(Hemiptera: Reduviidae)
Authors: Meraz-Medina T , Nogueda-Torres B , Martínez-Ibarra J A
Published: July 2022

Dipetalogaster maxima (Uhler) is a triatomine species that has been found to be infected by Trypanosoma cruzi Chagas in the habitats of the most important tourist areas of Mexico. Its behavior and vectorial capacity have been scarcely studied, although such information is necessary to reliably estimate the importance of this species as a vector of T. cruzi in its distribution area. This study reports biological parameters related to the vectorial capacity of D. maxima. In particular, the egg-to-adult development time, number of blood meals required to molt, accumulative mortality, time to beginning of feeding, feeding and defecation times, fecundity, and fertility were examined. D. maxima took a median of 211 d to develop from egg to adult, requiring 11 meals in total. Almost two-thirds (63%) of specimens died during the cycle. The time to beginning of feeding was 1 min in all instars. Feeding times varied from 14 to 27 min. Most nymphs (except first-instar) defecated when feeding or immediately thereafter. A mean of 0.7 eggs/♀/day was recorded, with an eclosion rate of 27.3%. Five of the eight studied parameters (mainly defecation delay) suggest the remarkable potential vectorial capacity of D. maxima, so it is necessary to maintain permanent surveillance of domiciliary populations of D. maxima, because they may be infected with T. cruzi.
Philadelphia’s news media system: which audiences are underserved?
Authors: Neff Timothy , Popiel Pawel , Pickard Victor
Published: July 2022

This study builds a multi-dimensional framework for assessing local media systems to identify potential gaps in news provision, especially among socioeconomically marginalized communities. We gather data on income, education, and age of audiences and coverage areas for 38 news outlets in Philadelphia and conduct a content analysis to gauge how these outlets meet critical information needs related to the COVID-19 pandemic. Findings indicate that multiple dimensions of Philadelphia’s news media system—audience size and socioeconomics, staffing levels, forms of ownership, and platform effects—work together to underserve communities with lower levels of income and education and that this structural gap generates a measurable gap in the provision of news content meeting the critical information needs of these communities. Policy interventions such as public funding and subsidies can enhance the capacity for Philadelphia news organizations to meet the critical information needs of marginalized communities.
Comparison of the NIO and EZIO for Resuscitative Vascular Access in the Emergency Department: A Quasi-Experimental, Before-and-After Study
Authors: Drumheller Byron C , Edgar Matthew D , Tape Meghan K , Vongviphut Don , Herres Joseph P
Published: July 2022

Introduction

Intraosseous (IO) needle insertion is a key adjunctive procedure in the care of critically ill and injured patients in a variety of settings, including the battlefield. The NIO is a new, fully disposable, single-piece, IO device with potential practical advantages under austere conditions. We sought to compare the efficacy and safety of the NIO to an established, well-studied device, the EZIO, when used for resuscitative vascular access in the emergency department (ED).

Methods

Retrospective, single-center, quasi-experimental, before-and-after, observational cohort study performed at an urban, tertiary-care hospital ED among adult patients receiving IO access during resuscitation. The before/NIO period lasted from July 1, 2019, to May 31, 2020, and the EZIO/after period from June 1, 2020, to April 30, 2021. Patient demographics, prehospital treatment, ED presentation, characteristics and results of IO insertion(s), potential procedure-associated adverse events, and ED and hospital outcomes were abstracted from the medical record. The primary outcome, rate of first-pass success (FPS), was compared between the NIO and EZIO periods using multivariable regression after adjustment for potential confounding factors.

Results

We enrolled 63 total patients/66 limbs (mean age 61 ± 18, 51% female), 34 patients/35 limbs during the NIO period and 29 patients/31 limbs during the EZIO period. The most common reason for IO insertion was cardiac arrest (40/63, 63%), followed by respiratory failure, trauma, and sepsis. The majority of IO insertions were performed at the proximal tibia (58/66, 88%) by senior emergency medicine residents or faculty. The overall rate of FPS was 53/66 (80%), 24/35 (69%) with the NIO compared to 29/31 (94%) with the EZIO. After multivariable modeling, the odds of FPS with the NIO vs. the EZIO was 0.19 (95% CI, 0.01–1.5, P = .16). Procedure-related adverse events were infrequent in both groups. In-hospital mortality was 45/63 (71%).

Conclusions

We found that the NIO device was associated with a lower-than-expected rate of FPS compared to the EZIO device, although not significantly different after adjusting for between-group imbalances and considering limitations in the study design. Further, prospective research into the efficacy and safety of the NIO is needed before clinical use can be encouraged.
Ocular Trauma and Traumatic Brain Injury on the Battlefield: A Systematic Review After 20 Years of Fighting the Global War on Terror
Authors: Lee Ian , Davis Brian , Purt Boonkit , DesRosiers Taylor
Published: July 2022

Introduction

Operations Iraqi Freedom and Enduring Freedom saw higher rates of combat ocular trauma (COT) than any past U.S. conflict. The improvised explosive device, the signature weapon of the conflicts, as well as improved personal protective equipment and combat medical care all attributed to COT being the fourth most common injury sustained by wounded U.S. service members. This review describes the epidemiology, mechanisms, and treatment patterns and discusses the relationship of traumatic brain injuries (TBIs) to ocular injuries sustained by U.S. service members during the War on Terror.

Materials and Methods

A mixed-methods review of the literature was conducted by extracting data from PubMed, Embase, and Cochrane research databases between December 15, 2020, and January 25, 2021, using the COVIDENCE review management software.

Results

Of 827 articles for review, 50 were deemed relevant. Articles were separated using the Birmingham Eye Trauma Terminology into open globe, closed globe, mixed/injury management only, and TBI. Seventeen articles were found to discuss data pertaining to particular databases. Overall, six articles discussed open-globe injuries in the setting of overall COT with a reported rate of 38-64%. Three articles discussed closed-globe injuries in the context of overall COT with a rate of 39-47%. Numerous articles discussed the relationship between COT and TBI. Within the Walter Reed Ocular Trauma Database, 40% of patients with ocular trauma had concomitant TBI. Additionally, the visual sequelae of ocular trauma ranged from 9% to 50% among reporting studies. Other ocular injury patterns receiving attention include neuro-ophthalmic and oculoplastic injuries. By far the most common mechanism of COT was blast injury (64-84%), with improvised explosive devices (IEDs) accounting for 51-69% of ocular injuries. Among the large reporting databases, 41-45% of COT required surgical treatment with an overall enucleation rate of 12-17%.

Conclusions

The Global War on Terrorism saw an evolution in the types of ocular injuries sustained by U.S. service members compared to previous conflicts. The widespread use of IEDs led to injury patterns not encountered in previous conflicts. Weapons of today utilize blast and shrapnel as the mechanism for destruction. Sequelae such as TBIs and complicated head and neck trauma have pushed innovation in the field of ophthalmology. Improvements in medical technology and personal protective equipment have resulted in not only survival of previously life-threatening injuries, but also a greater chance of severe loss of vision. By analyzing ocular injury data from the trauma literature, improvements in education and training can lead to improvements in point-of-injury care and eye protection for the next generation of warfighters.
Ozonated oil is effective at killing Candida species and Streptococcus mutans biofilm-derived cells under aerobic and microaerobic conditions
Authors: Higa Barbara , Cintra Bianca Souza , Álvarez Carmen Magaly , Ribeiro Arthur Barcelos , Ferreira Jair Camargo , Tavares Denise Crispim , Enriquez Vanessa , Martinez Luis R , Pires Regina Helena
Published: July 2022

This study explores the growth of bacterial, fungal, and interkingdom biofilms under aerobiosis or microaerobic conditions and the effect of ozonated sunflower oil on these biofilms. Candida species and Streptococcus mutans were used to study this interaction due to their importance in oral health and disease as these microorganisms display a synergistic relationship that manifests in the onset of caries and tooth decay. Biofilms were developed in a 96-well microtiter plate at 37ºC for 24 h, under aerobiosis or microaerobic conditions, and treated with ozonated oil for 5 to 120 min. All the microorganisms formed biofilms in both oxygenation conditions. Scanning electron microscopy was used to visualize biofilm morphology. Rodent experiments were performed to verify the oil-related toxicity and its efficacy in oral candidiasis. The growth of all Candida species was increased when co-cultured with S. mutans, whilst the growth of bacterium was greater only when co-cultured with C. krusei and C. orthopsilosis under aerobiosis and microaerobic conditions, respectively. Regardless of the oxygenation condition, ozonated oil significantly reduced the viability of all the tested biofilms and infected mice, showing remarkable microbicidal activity as corroborated with confocal microscopy and minimal toxicity. Thus, ozonated oil therapy can be explored as a strategy to control diseases associated with these biofilms especially in the oral cavity.

Lay Summary

We demonstrated that ozonated sunflower oil is effective at killing the biofilms formed by Candida species, by the bacterium Streptococcus mutans, or by both micoorganisms that can interact in the oral cavity, making it a potential therapeutic option for the treatment of these infections.
Radio emission from simulated tidal disruption events
Authors: Spaulding Alexandra , Chang Philip
Published: July 2022

Several tidal disruption events such as ASASSN-14li and XMMSL1 J0740-85 have recently been observed in the radio. While the radio emission of some tidal disruption events are attributed to a relativistic jet, a few others are associated with a non-relativistic outflow. This outflow can either be due to a spherical wind or unbound tidal debris. We explore this latter hypothesis in this paper. We show that the maximum velocity of the unbound debris is a function of the impact parameter, such that smaller impact parameters (closer approaches) produce larger maximum velocities. We then model this outflow which expands and shocks the local interstellar medium and compute the peak radio flux and frequency as functions of the impact parameter. Moreover, multiple epochs of observations can put additional constraints on the profile of the local interstellar medium. We apply this analysis to four tidal disruption events whose radio emission is attributed to a non-relativistic outflow and show that the velocities of the unbound material are consistent with our simulated events. We also place constraints on the density profile of three of the four tidal disruption events with multiple epochs of observations.
What leads to premature upper cut-off frequencies of auroral radio emission from hot magnetic stars?
Authors: Das Barnali , Chandra Poonam , Petit Véronique
Published: July 2022

Recently, a large number of hot magnetic stars have been discovered to produce auroral radio emission by the process of electron cyclotron maser emission (ECME). Such stars have been given the name of main-sequence radio pulse emitters (MRPs). The phenomenon characterizing MRPs is very similar to that exhibited by planets like Jupiter. However, one important aspect in which the MRPs differ from aurorae exhibited by planets is the upper cut-off frequency of the ECME spectrum. While Jupiter’s upper cut-off frequency was found to correspond to its maximum surface magnetic field strength, the same for MRPs are always found to be much smaller than the frequencies corresponding to their maximum surface magnetic field strength. In this paper, we report the wideband observations (0.4–4.0 GHz) of the MRP HD 35298 that enabled us to locate the upper cut-off frequency of its ECME spectrum. This makes HD 35298 the sixth MRP with a known constraint on the upper cut-off frequency. With this information, for the first time, we investigate into what could lead to the premature cut-off. We review the existing scenarios attempting to explain this effect, and arrive at the conclusion that none of them can satisfactorily explain all the observations. We speculate that more than one physical processes might be in play to produce the observed characteristics of ECME cut-off for hot magnetic stars. Further observations, both for discovering more hot magnetic stars producing ECME and to precisely locate the upper cut-off, will be critical to solve this problem.
Lyman alpha and Lyman continuum emission of Mg ii-selected star-forming galaxies
Authors: Izotov Y I , Chisholm J , Worseck G , Guseva N G , Schaerer D , Prochaska J X
Published: July 2022

We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of seven compact low-mass star-forming galaxies at redshifts, z, in the range 0.3161–0.4276, with various O3Mg2 = [O iii] λ5007/Mg ii λ2796+2803 and Mg2 = Mg ii λ2796/Mg ii λ2803 emission-line ratios. We aim to study the dependence of leaking Lyman continuum (LyC) emission on the characteristics of Mg ii emission together with the dependencies on other indirect indicators of escaping ionizing radiation. LyC emission with escape fractions fesc(LyC) = 3.1–4.6 per cent is detected in four galaxies, whereas only 1σ upper limits of fesc(LyC) in the remaining three galaxies were derived. A strong narrow Lyα emission line with two peaks separated by $V_{\rm sep}\, \sim$ 298–592 km s−1 was observed in four galaxies with detected LyC emission and very weak Lyα emission is observed in galaxies with LyC non-detections. Our new data confirm the tight anticorrelation between fesc(LyC) and Vsep found for previous low-redshift galaxy samples. Vsep remains the best indirect indicator of LyC leakage among all considered indicators. It is found that escaping LyC emission is detected predominantly in galaxies with Mg$_2\, \gtrsim$ 1.3. A tendency of an increase of fesc(LyC) with increasing of both the O3Mg2 and Mg2 is possibly present. However, there is substantial scatter in these relations not allowing their use for reliable prediction of fesc(LyC).
The nature of the radio source detected towards the exoplanet system 1RXS1609.1−210524
Authors: Narang Mayank
Published: July 2022

Several studies have been carried out to detect radio emissions from known exoplanets. Some of these studies have resulted in tentative detections of radio sources near the position of known exoplanets. One such planet/brown dwarf around which a radio source was detected is 1RXS1609.1−210524 (hereafter 1RX) b. A radio source near 1RX was detected with the TIFR GMRT Sky Survey (TGSS) at 150 MHz and the NRAO VLA Sky Survey (NVSS) at 1.4 GHz. However, since these surveys’ spatial resolution was low, it was not possible to ascertain whether the radio emission originated from the system or a background source. This work presents results from the 1RX field’s targeted observations at 150, 325, and 610 MHz with Giant Meterwave Radio Telescope (GMRT). These observations have a higher angular resolution as compared to TGSS and NVSS. I detected the radio source near the position of 1RX at all frequencies with GMRT. I further used the Very Large Array Sky Survey (VLASS) data at 3 GHz to determine the flux density and position at high frequency. With the targeted GMRT observations and observations from VLASS, I show that the radio emission does not originate from the 1RX b but is from a background source about ∼13 arcsec away from the host star. Further, no radio emission was detected from the position of 1RX.
Simulating the night-time astronomical seeing at Dome A using Polar WRF
Authors: Yang Qike , Wu Xiaoqing , Wang Zhiyuan , Hu Xiaodan , Guo Yiming , Qing Chun
Published: July 2022

In Antarctica, excellent astronomical observing conditions have been measured at Dome A during night-time (or polar winter). This study investigates the performance of the Polar-optimized version of the Weather Research and Forecasting (Polar WRF, PWRF hereafter) for simulating the night-time astronomical seeing at Dome A. The seeing values were estimated by a seeing model, which used the PWRF-simulated wind speed and temperature as inputs. Furthermore, three methods to obtain the boundary layer height in the seeing model have been examined. The estimated seeing agrees well with 50-d measurements from the KunLun Differential Image Motion Monitor at Dome A during the night-time of 2019; the correlation coefficients range from 0.62 to 0.71. The PWRF-simulated meteorological parameters indicate that low wind speed and strong temperature inversion (when a large gradient Richardson number always occurs) near the ground can lead to good seeing condition. The results suggest that the PWRF model could be a reliable tool for scheduling observational astronomy at Dome A during night-time.
The DESI N-body simulation project – I. Testing the robustness of simulations for the DESI dark time survey
Authors: Grove Cameron , Chuang Chia-Hsun , Devi Ningombam Chandrachani , Garrison Lehman , L’Huillier Benjamin , Feng Yu , Helly John , Hernández-Aguayo César , Alam Shadab , Zhang Hanyu , Yu Yu , Cole Shaun , Eisenstein Daniel , Norberg Peder , Wechsler Risa , Brooks David , Dawson Kyle , Landriau Martin , Meisner Aaron , Poppett Claire , Tarlé Gregory , Valenzuela Octavio
Published: July 2022

Analysis of large galaxy surveys requires confidence in the robustness of numerical simulation methods. The simulations are used to construct mock galaxy catalogues to validate data analysis pipelines and identify potential systematics. We compare three N-body simulation codes, abacus, gadget-2, and swift, to investigate the regimes in which their results agree. We run N-body simulations at three different mass resolutions, 6.25 × 108, 2.11 × 109, and 5.00 × 109 h−1 M⊙, matching phases to reduce the noise within the comparisons. We find systematic errors in the halo clustering between different codes are smaller than the Dark Energy Spectroscopic Instrument (DESI) statistical error for $s\ \gt\ 20\ h^{-1}$ Mpc in the correlation function in redshift space. Through the resolution comparison we find that simulations run with a mass resolution of 2.1 × 109 h−1 M⊙ are sufficiently converged for systematic effects in the halo clustering to be smaller than the DESI statistical error at scales larger than $20\ h^{-1}$ Mpc. These findings show that the simulations are robust for extracting cosmological information from large scales which is the key goal of the DESI survey. Comparing matter power spectra, we find the codes agree to within 1 per cent for k ≤ 10 h Mpc−1. We also run a comparison of three initial condition generation codes and find good agreement. In addition, we include a quasi-N-body code, FastPM, since we plan use it for certain DESI analyses. The impact of the halo definition and galaxy–halo relation will be presented in a follow-up study.
Modelling the galaxy–halo connection with machine learning
Authors: Delgado Ana Maria , Wadekar Digvijay , Hadzhiyska Boryana , Bose Sownak , Hernquist Lars , Ho Shirley
Published: July 2022

To extract information from the clustering of galaxies on non-linear scales, we need to model the connection between galaxies and haloes accurately and in a flexible manner. Standard halo occupation distribution (HOD) models make the assumption that the galaxy occupation in a halo is a function of only its mass, however, in reality; the occupation can depend on various other parameters including halo concentration, assembly history, environment, and spin. Using the IllustrisTNG hydrodynamical simulation as our target, we show that machine learning tools can be used to capture this high-dimensional dependence and provide more accurate galaxy occupation models. Specifically, we use a random forest regressor to identify which secondary halo parameters best model the galaxy–halo connection and symbolic regression to augment the standard HOD model with simple equations capturing the dependence on those parameters, namely the local environmental overdensity and shear, at the location of a halo. This not only provides insights into the galaxy formation relationship but also, more importantly, improves the clustering statistics of the modelled galaxies significantly. Our approach demonstrates that machine learning tools can help us better understand and model the galaxy–halo connection, and are therefore useful for galaxy formation and cosmology studies from upcoming galaxy surveys.
Impacts of zonal winds on planetary oscillations and Saturn ring seismology
Authors: Dewberry Janosz W , Mankovich Christopher R , Fuller Jim
Published: July 2022

The excitation of density and bending waves in Saturn’s C ring by planetary oscillation modes presents a unique opportunity to learn about gas giant interiors and rotation. However, theoretical complications related to Saturn’s rapid and differential rotation pose a barrier to the full utilization of ring wave detections. We calculate oscillation modes using a complete, non-perturbative treatment of differential rotation modelled after Saturn’s zonal winds in self-consistently computed, polytropic equilibria. We find that previous, approximate treatments of the effects of differential rotation in Saturn overestimate shifts in the frequencies of fundamental modes (f modes) thought to be responsible for the majority of the waves detected in the C ring, due to an omitted modification of the equilibrium shape and structure of the planet by differential rotation. The bias introduced by these frequency overestimates is small, but significant relative to the uncertainties afforded by Cassini data. We additionally consider the non-perturbative effects of Saturn-like differential rotation on the rotational mixing of f modes and internal gravity modes (g modes), which is relevant to detections of multiple density waves with very closely split pattern speeds. We find that higher-order rotational effects can produce orders-of-magnitude enhancements in the surface gravitational perturbations of g modes dominated by large spherical harmonic degrees ℓ, regardless of frequency separation from the sectoral f mode. Despite this enhancement, we find that the observed fine splitting of density waves is unlikely to involve g modes dominated by ℓ ≳ 10. This restriction may aid in the inference of possible internal structures for Saturn.
The stellar parameters and elemental abundances from low-resolution spectra – I. 1.2 million giants from LAMOST DR8
Authors: Li Zhuohan , Zhao Gang , Chen Yuqin , Liang Xilong , Zhao Jingkun
Published: July 2022

As a typical data-driven method, deep learning becomes a natural choice for analysing astronomical data. In this study, we built a deep convolutional neural network (NN) to estimate basic stellar parameters $T\rm {_{eff}}$, log g, metallicity ([M/H] and [Fe/H]) and [α/M] along with nine individual elemental abundances ([C/Fe], [N/Fe], [O/Fe], [Mg/Fe], [Al/Fe], [Si/Fe], [Ca/Fe], [Mn/Fe], and [Ni/Fe]). The NN is trained using common stars between the APOGEE survey and the LAMOST survey. We used low-resolution spectra from LAMOST survey as input, and measurements from APOGEE as labels. For stellar spectra with the signal-to-noise ratio in g band larger than 10 in the test set, the mean absolute error (MAE) is 29 K for $T\rm {_{eff}}$, 0.07 dex for log g, 0.03 dex for both [Fe/H] and [M/H], and 0.02 dex for [α/M]. The MAE of most elements is between 0.02 and 0.04 dex. The trained NN was applied to 1210 145 giants, including sub-giants, from LAMOST DR8 within the range of stellar parameters 3500 K < $T\rm {_{eff}}$ < 5500 K, 0.0 dex < log g < 4.0 dex, −2.5 dex < [Fe/H] < 0.5 dex. The distribution of our results in the chemical spaces is highly consistent with APOGEE labels and stellar parameters show consistency with external high-resolution measurements from GALAH. The results in this study allow us to further studies based on LAMOST data and deepen our understanding of the accretion and evolution history of the Milky Way. The electronic version of the value added catalog is available at http://www.lamost.org/dr8/v1.1/doc/vac.
Extended planetary chaotic zones
Authors: Shevchenko Ivan I
Published: July 2022

We consider the chaotic motion of low-mass bodies in two-body high-order mean-motion resonances with planets in model planetary systems, and analytically estimate the Lyapunov and diffusion time-scales of the motion in multiplets of interacting subresonances corresponding to the mean-motion resonances. We show that the densely distributed (though not overlapping) high-order mean-motion resonances, when certain conditions on the planetary system parameters are satisfied, may produce extended planetary chaotic zones – ‘zones of weak chaotization,’ – much broader than the well-known planetary connected chaotic zone, the Wisdom gap. This extended planetary chaotic zone covers the orbital range between the 2/1 and 1/1 resonances with the planet. On the other hand, the orbital space inner (closer to the host star) with respect to the 2/1 resonance location is essentially long-term stable. This difference arises because the adiabaticity parameter of subresonance multiplets specifically depends on the particle’s orbit size. The revealed effect may control the structure of planetesimal discs in planetary systems: the orbital zone between the 2/1 and 1/1 resonances with a planet should be normally free from low-mass material (only that occasionally captured in the first-order 3/2 or 4/3 resonances may survive); whereas any low-mass population inner to the 2/1 resonance location should be normally long-lived (if not perturbed by secular resonances, which we do not consider in this study).
Astrophysical gravitational-wave echoes from galactic nuclei
Authors: Gondán László , Kocsis Bence
Published: July 2022

Galactic nuclei (GNs) are dense stellar environments abundant in gravitational-wave (GW) sources for the Laser Interferometer Gravitational-Wave Observatory (LIGO), Virgo, and Kamioka Gravitational Wave Detector (KAGRA). The GWs may be generated by stellar-mass black hole (BH) or neutron star mergers following gravitational bremsstrahlung, dynamical scattering encounters, Kozai–Lidov-type oscillations driven by the central supermassive black hole (SMBH), or gas-assisted mergers if present. In this paper, we examine a smoking gun signature to identify sources in GNs: the GWs scattered by the central SMBH. This produces a secondary signal, an astrophysical GW echo, which has a very similar time–frequency evolution as the primary signal but arrives after a time delay. We determine the amplitude and time-delay distribution of the GW echo as a function of source distance from the SMBH. Between ${\sim} 10{{\ \rm per\ cent}}\hbox{ and }90{{\ \rm per\ cent}}$ of the detectable echoes arrive within ${\sim} (1\hbox{--}100)M_6\, \mathrm{s}$ after the primary GW for sources between 10 and 104 Schwarzschild radius, where $M_6=M_{{\rm SMBH},z}/(10^6\, \mathrm{M}_{\odot })$, and MSMBH, z is the observer-frame SMBH mass. The echo arrival times are systematically longer for high signal-to-noise ratio (SNR) primary GWs, where the GW echo rays are scattered at large deflection angles. In particular, ${\sim} 10{{\ \rm per\ cent}}\hbox{--}90{{\ \rm per\ cent}}$ of the distribution is shifted to ${\sim} (5\hbox{--}1800)M_6\, \mathrm{s}$ for sources, where the lower limit of echo detection is 0.02 of the primary signal amplitude. We find that ${\sim} 5{{\ \rm per\ cent}}\hbox{--}30{{\ \rm per\ cent}}$ (${\sim} 1{{\ \rm per\ cent}}\hbox{--}7{{\ \rm per\ cent}}$) of GW sources have an echo amplitude larger than 0.2–0.05 times the amplitude of the primary signal if the source distance from the SMBH is 50 (200) Schwarzschild radius. Non-detections can rule out that a GW source is near an SMBH.
On the accretion of a new group of galaxies on to Virgo – II. The effect of pre-processing on the stellar population content of dEs
Authors: Bidaran Bahar , La Barbera Francesco , Pasquali Anna , Peletier Reynier , van de Ven Glenn , Grebel Eva K , Falcón-Barroso Jesus , Sybilska Agnieszka , Gadotti Dimitri A , Coccato Lodovico
Published: July 2022

Using MUSE spectra, we investigate how pre-processing and accretion on to a galaxy cluster affect the integrated stellar population properties of dwarf early-type galaxies (dEs). We analyse a sample of nine dEs with stellar masses of $\rm \sim 10^9 \, M_\odot$, which were accreted (∼ 2–3 Gyr ago) on to the Virgo cluster as members of a massive galaxy group. We derive their stellar population properties, namely age, metallicity ([M/H]), and the abundance ratio of α elements ([α/Fe]), by fitting observed spectral indices with a robust, iterative procedure, and infer their star formation history (SFH) by means of full spectral fitting. We find that these nine dEs are more metal-poor (at the 2–3σ level) and significantly more α-enhanced than dEs in the Virgo and Coma clusters with similar stellar mass, clustercentric distance, and infall time. Moreover, for six dEs, we find evidence for a recent episode of star formation during or right after the time of accretion on to Virgo. We interpret the high [α/Fe] of our sample of dEs as the result of the previous exposure of these galaxies to an environment hostile to star formation, and/or the putative short burst of star formation they underwent after infall into Virgo. Our results suggest that the stellar population properties of low-mass galaxies may be the result of the combined effect of pre-processing in galaxy groups and environmental processes (such as ram-pressure triggering star formation) acting during the early phases of accretion on to a cluster.
Impulsively generated kink wave trains in solar coronal slabs
Authors: Guo Mingzhe , Li Bo , Van Doorsselaere Tom , Shi Mijie
Published: July 2022

We numerically follow the response of density-enhanced slabs to impulsive, localized, transverse velocity perturbations by working in the framework of ideal magnetohydrodynamics (MHD). Both linear and non-linear regimes are addressed. Kink wave trains are seen to develop along the examined slabs, sharing the characteristics that more oscillatory patterns emerge with time and that the apparent wavelength increases with distance at a given instant. Two features none the less arise due to non-linearity, one being a density cavity close to the exciter and the other being the appearance of shocks both outside and inside the nominal slab. These features may be relevant for understanding the interaction between magnetic structures and such explosive events as coronal mass ejections. Our numerical findings on kink wave trains in solar coronal slabs are discussed in connection with typical measurements of streamer waves.
Forecasting the solar cycle 25 using a multistep Bayesian neural network
Authors: Bizzarri I , Barghini D , Mancuso S , Alessio S , Rubinetti S , Taricco C
Published: July 2022

Predicting the solar activity of upcoming cycles is crucial nowadays to anticipate potentially adverse space weather effects on the Earth’s environment produced by coronal transients and traveling interplanetary disturbances. The latest advances in deep learning techniques provide new paradigms to obtain effective prediction models that allow to forecast in detail the evolution of cosmogeophysical time series. Because of the underlying complexity of the dynamo mechanism in the solar interior that is at the origin of the solar cycle phenomenon, the predictions offered by state-of-the-art machine learning algorithms represent valuable tools for our understanding of the cycle progression. As a plus, Bayesian deep learning is particularly compelling thanks to recent advances in the field that provide improvements in both accuracy and uncertainty quantification compared to classical techniques. In this work, a deep learning long short-term memory model is employed to predict the complete profile of Solar Cycle 25, thus forecasting also the advent of the next solar minimum. A rigorous uncertainty estimation of the predicted sunspot number is obtained by applying a Bayesian approach. Two different model validation techniques, namely the Train-Test split and the time series k-fold cross-validation, have been implemented and compared, giving compatible results. The forecasted peak amplitude is lower than that of the preceding cycle. Solar Cycle 25 will last 10.6 ± 0.7 yr, reaching its maximum in the middle of the year 2024. The next solar minimum is predicted in 2030 and will be as deep as the previous one.
On the moment of inertia of PSR J0737-3039 A from LIGO/Virgo and NICER
Authors: Miao Zhiqiang , Li Ang , Dai Zi-Gao
Published: July 2022

We perform a Bayesian analysis of neutrons star moment of inertia by utilizing the available gravitational-wave data from LIGO/Virgo (GW170817 and GW190425) and mass-radius measurements from the Neutron Star Interior Composition Explorer (PSR J0030+0415 and PSR J0740 + 6620), incorporating the possible phase transition in the pulsar inner core. We find that the moment of inertia of pulsar A in the double pulsar binary J0737-3039 is $\sim 1.30\times 10^{45}\, {\rm g\, cm^2}$, which only slightly depends on the employed hadronic equation of states. We also demonstrate how a moment of inertia measurement would improve our knowledge of the equation of state and the mass–radius relation for neutron stars and discuss whether a quark deconfinement phase transition is supported by the available data and forthcoming data that could be consistent with this hypothesis. We find that if pulsar A is a quark star, its moment of inertia is a large value of $\sim 1.55\times 10^{45}\, {\rm g\, cm^2}$ suggesting the possibility of distinguishing it from (hybrid-)neutron stars with measurements of PSR J0737-3039A moment of inertia. We finally demonstrate the moment-of-inertia-compactness universal relations and provide analytical fits for both (hybrid-)neutron star and quark star results based on our analysis.
SDSS-IV MaNGA: global properties of kinematically misaligned galaxies
Authors: Zhou Yuren , Chen Yanmei , Shi Yong , Bizyaev Dmitry , Guo Hong , Bao Min , Xu Haitong , Yu Xiaoling , Brownstein Joel R
Published: July 2022

We select 456 gas–star kinematically misaligned galaxies from the internal Product Launch-10 of MaNGA survey, including 74 star-forming (SF), 136 green-valley (GV), and 206 quiescent (QS) galaxies. We find that the distributions of difference between gas and star position angles for galaxies have three local peaks at ∼0°, 90°, and 180°. The fraction of misaligned galaxies peaks at log (M*/M⊙) ∼ 10.5 and declines to both low- and high-mass end. This fraction decreases monotonically with increasing star formation rate and specific star formation rate. We compare the global parameters including gas kinematic asymmetry Vasym, H i detection rate and mass fraction of molecular gas, effective radius Re, Sérsic index n as well as spin parameter $\lambda _{R_e}$ between misaligned galaxies and their control samples. We find that the misaligned galaxies have lower H i detection rate and molecular gas mass fraction, smaller size, higher Sérsic index, and lower spin parameters than their control samples. The SF and GV misaligned galaxies are more asymmetric in gas velocity fields than their controls. These pieces of observational evidence point to the gas accretion scenario followed by angular momentum redistribution from gas–gas collision, leading to gas inflow and central star formation for the SF and GV misaligned galaxies. We propose three possible origins of the misaligned QS galaxies: (1) external gas accretion, (2) merger, and (3) GV misaligned galaxies evolve into QS galaxies.
The K2 Galactic Archaeology Program: Overview, target selection, and survey properties
Authors: Sharma Sanjib , Stello Dennis , Zinn Joel C , Reyes Claudia , Hon Marc , Bland-Hawthorn Joss
Published: July 2022

K2 was a community-driven NASA mission where all targets were proposed through guest observer programmes. Here we provide an overview of one of the largest of these endeavours, the K2 Galactic Archaeology Programme (K2GAP), with about 25 per cent of the observed targets being allocated to this programme. K2GAP provides asteroseismic parameters for about 23 000 giant stars across the Galaxy, which together with spectroscopic stellar parameters can give age and masses of stars. We discuss in detail the target selection procedure and provide a python program that implements the selection function (github.com/sanjibs/k2gap). Broadly speaking, the targets were selected on 2MASS colour J − Ks > 0.5, with finely tuned adjustments for each campaign. We discuss the detection completeness of the asteroseismic parameters νmax and Δν. About 14 per cent of giants were found to miss νmax detections and it was difficult to detect Δν for RC stars. Making use of the selection function, we compare the observed distribution of asteroseismic masses to theoretical predictions. The median asteroseismic mass is higher by about 4 per cent compared to predictions. We provide a selection-function-matched mock catalogue of stars based on a synthetic model of the Galaxy for the community to use in subsequent analyses of the K2GAP data set (physics.usyd.edu.au/k2gap/download/).