bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemo-dynamics of outer halo dwarf stars, including Gaia-Sausage and Gaia-Sequoia candidates
Authors: Monty Stephanie , Venn Kim A , Lane James M M , Lokhorst Deborah , Yong David 
Published: July 2020

ABSTRACT
The low-metallicity, kinematically interesting dwarf stars studied by Stephens & Boesgaard (2002, SB02) are re-examined using Gaia DR2 astrometry, and updated model atmospheres and atomic line data. New stellar parameters are determined based on the Gaia DR2 parallactic distances and Dartmouth Stellar Evolution Database isochrones. These are in excellent agreement with spectroscopically determined stellar parameters for stars with [Fe/H] &gt; −2; however, large disagreements are found for stars with [Fe/H] ≤ −2, with offsets as large as ΔTeff ∼ +500 K and Δlog g ∼ +1.0. A subset of six stars (test cases) are analysed ab initio using high-resolution spectra with Keck HIRES and Gemini GRACES. This sub-sample is found to include two α-challenged dwarf stars, suggestive of origins in a low-mass, accreted dwarf galaxy. The orbital parameters for the entire SB02 sample are re-determined using Gaia DR2 data. We find 11 stars that are dynamically coincident with the Gaia-Sausage accretion event and another 17 with the Gaia-Sequoia event in action space. Both associations include low-mass, metal-poor stars with isochrone ages older than 10 Gyr. Two dynamical subsets are identified within Gaia-Sequoia. When these subsets are examined separately, a common knee in [α/Fe] is found for the Gaia-Sausage and low orbital energy Gaia-Sequoia stars. A lower metallicity knee is tentatively identified in the Gaia-Sequoia high orbital energy stars. If the metal-poor dwarf stars in these samples are true members of the Gaia-Sausage and Gaia-Sequoia events, then they present a unique opportunity to probe the earlier star formation histories of these systems.
Radio variability from corotating interaction regions threading Wolf–Rayet winds
Authors: Ignace Richard , St-Louis Nicole , Prinja Raman K 
Published: July 2020

ABSTRACT
The structured winds of single massive stars can be classified into two broad groups: stochastic structure and organized structure. While the former is typically identified with clumping, the latter is typically associated with rotational modulations, particularly the paradigm of corotating interaction regions (CIRs). While CIRs have been explored extensively in the ultraviolet band, and moderately in the X-ray and optical, here we evaluate radio variability from CIR structures assuming free–free opacity in a dense wind. Our goal is to conduct a broad parameter study to assess the observational feasibility, and to this end, we adopt a phenomenological model for a CIR that threads an otherwise spherical wind. We find that under reasonable assumptions, it is possible to obtain radio variability at the 10 per cent level. The detailed structure of the folded light curve depends not only on the curvature of the CIR, the density contrast of the CIR relative to the wind, and viewing inclination, but also on wavelength. Comparing light curves at different wavelengths, we find that the amplitude can change, that there can be phase shifts in the waveform, and the entire waveform itself can change. These characterstics could be exploited to detect the presence of CIRs in dense, hot winds.
Dynamics of black hole–neutron star binaries in young star clusters
Authors: Rastello Sara , Mapelli Michela , Di Carlo Ugo N , Giacobbo Nicola , Santoliquido Filippo , Spera Mario , Ballone Alessandro , Iorio Giuliano 
Published: July 2020

ABSTRACT
Young star clusters are likely the most common birthplace of massive stars across cosmic time and influence the formation of compact binaries in several ways. Here, we simulate the formation of black hole–neutron star binaries (BHNSs) in young star clusters, by means of the binary population synthesis code MOBSE interfaced with the N-body code NBODY6++GPU. BHNSs formed in young star clusters (dynamical BHNSs) are significantly more massive than BHNSs formed from isolated binaries (isolated BHNSs): ∼40 per cent of the dynamical BHNS mergers have a total mass of &gt;15 M⊙, while only ∼0.01 per cent of the isolated BHNS mergers have mass in excess of this value. Hence, our models strongly support a dynamical formation scenario for GW190814, given its total mass of ∼26 M⊙, if this event is a BHNS merger. All our dynamical BHNSs are ejected from their parent star cluster before they reach coalescence. Thus, a significant fraction of BHNS mergers occurring in the field might have originated in a young star cluster. The mass spectrum of BHNS mergers from gravitational-wave detections will provide a clue to differentiate between dynamical and isolated formation of BHNSs.
Weak-lensing observables in relativistic N-body simulations
Authors: Lepori Francesca , Adamek Julian , Durrer Ruth , Clarkson Chris , Coates Louis 
Published: July 2020

ABSTRACT
We present a numerical weak-lensing analysis that is fully relativistic and non-perturbative for the scalar part of the gravitational potential and first order in the vector part, frame dragging. Integrating the photon geodesics backwards from the observer to the emitters, we solve the Sachs optical equations and study in detail the weak-lensing convergence, ellipticity and rotation. For the first time, we apply such an analysis to a high-resolution relativistic N-body simulation, which consistently includes the leading-order corrections due to general relativity on both large and small scales. These are related to the question of gauge choice and to post-Newtonian corrections, respectively. We present the angular power spectra and one-point probability distribution functions for the weak-lensing variables, which we find are broadly in agreement with comparable Newtonian simulations. Our geometric approach, however, is more robust and flexible, and can therefore be applied consistently to non-standard cosmologies and modified theories of gravity.
Role of cosmic rays in the early stages of galactic outflows
Authors: Jana Ranita , Gupta Siddhartha , Nath Biman B 
Published: July 2020

ABSTRACT
Using an idealized set-up, we investigate the dynamical role of cosmic rays (CRs) in the early stages of galactic outflows for galaxies of halo masses 108, 1011, and 1012 M⊙. The outflow is launched from a central region in the galactic disc where we consider three different constant star formation rates (0.1, 1, and 10 $\mathrm{M}_\odot \, \mathrm{yr}^{-1}$) over a dynamical time-scale of 50 Myr. We determine the temperature distribution of the gas and find that CRs can reduce the temperature of the shocked gas, which is consistent with previous results. However, we show that CRs do not have any noticeable effect on the mass loading by the outflow. We find that CRs can reduce the size of the outflow, which contradicts previous claims of efficient dynamical impact of CRs; however, it is consistent with earlier theoretical models of CR-driven blastwave as well as stellar wind. We discuss the dependence of our results on CR injection prescriptions and compare them with earlier studies. We conclude that in the early stages of galactic outflows the dynamical role of CRs is not important.
ExoMol line lists – XL. Rovibrational molecular line list for the hydronium ion (H3O+)
Authors: Yurchenko S N , Tennyson Jonathan , Miller Steve , Melnikov V V , O’Donoghue J , Moore L 
Published: July 2020

ABSTRACT
A new line list for hydronium (H316O+) is computed. The line list is based on a new ab initio dipole moment surface (CCSD(T)/aug-cc-pVQZ) and a new empirical potential energy surface (PES). The empirical PES of H3O+ was obtained by refining an ab initio surface through a global fit to the experimentally determined rovibrational energies collected from the literature covering the ground, $\nu _1^{\pm }$, $\nu _2^{\pm }$, $2\nu _2^{\pm }$, $\nu _3^{\pm }$, and $\nu _4^{\pm }$ vibrational states. The line list covers the wavenumber range up to 10 000 cm−1 (wavelengths $\gt 1 \, \mu$m) and should be complete for temperatures up to T = 1500 K. This is the first comprehensive line list for H3O+ with extensive wavenumber coverage and accurate transitional probabilities. Prospects of detection of hydronium in spectra of Solar system giant planets as well as exoplanets are discussed. The eXeL line list is publicly available from the ExoMol and CDS data bases.
Genome-Wide Association Analysis Identifies a Genetic Basis of Infectivity in a Model Bacterial Pathogen
Authors: Andras Jason P , Fields Peter D , Du Pasquier Louis , Fredericksen Maridel , Ebert Dieter 
Published: July 2020

AbstractKnowledge of the genetic architecture of pathogen infectivity and host resistance is essential for a mechanistic understanding of coevolutionary processes, yet the genetic basis of these interacting traits remains unknown for most host–pathogen systems. We used a comparative genomic approach to explore the genetic basis of infectivity in Pasteuria ramosa, a Gram-positive bacterial pathogen of planktonic crustaceans that has been established as a model for studies of Red Queen host–pathogen coevolution. We sequenced the genomes of a geographically, phenotypically, and genetically diverse collection of P. ramosa strains and performed a genome-wide association study to identify genetic correlates of infection phenotype. We found multiple polymorphisms within a single gene, Pcl7, that correlate perfectly with one common and widespread infection phenotype. We then confirmed this perfect association via Sanger sequencing in a large and diverse sample set of P. ramosa clones. Pcl7 codes for a collagen-like protein, a class of adhesion proteins known or suspected to be involved in the infection mechanisms of a number of important bacterial pathogens. Consistent with expectations under Red Queen coevolution, sequence variation of Pcl7 shows evidence of balancing selection, including extraordinarily high diversity and absence of geographic structure. Based on structural homology with a collagen-like protein of Bacillus anthracis, we propose a hypothesis for the structure of Pcl7 and the physical location of the phenotype-associated polymorphisms. Our results offer strong evidence for a gene governing infectivity and provide a molecular basis for further study of Red Queen dynamics in this model host–pathogen system.
Allopatric and Sympatric Drivers of Speciation inAlviniconchaHydrothermal Vent Snails
Authors: Breusing Corinna , Johnson Shannon B , Tunnicliffe Verena , Clague David A , Vrijenhoek Robert C , Beinart Roxanne A 
Published: July 2020

AbstractDespite significant advances in our understanding of speciation in the marine environment, the mechanisms underlying evolutionary diversification in deep-sea habitats remain poorly investigated. Here, we used multigene molecular clocks and population genetic inferences to examine processes that led to the emergence of the six extant lineages of Alviniconcha snails, a key taxon inhabiting deep-sea hydrothermal vents in the Indo-Pacific Ocean. We show that both allopatric divergence through historical vicariance and ecological isolation due to niche segregation contributed to speciation in this genus. The split between the two major Alviniconcha clades (separating A. boucheti and A. marisindica from A. kojimai, A. hessleri, and A. strummeri) probably resulted from tectonic processes leading to geographic separation, whereas the splits between co-occurring species might have been influenced by ecological factors, such as the availability of specific chemosynthetic symbionts. Phylogenetic origin of the sixth species, Alviniconcha adamantis, remains uncertain, although its sister position to other extant Alviniconcha lineages indicates a possible ancestral relationship. This study lays a foundation for future genomic studies aimed at deciphering the roles of local adaptation, reproductive biology, and host–symbiont compatibility in speciation of these vent-restricted snails.
Unconventional Hall effect induced by Berry curvature
Authors: Ge Jun , Ma Da , Liu Yanzhao , Wang Huichao , Li Yanan , Luo Jiawei , Luo Tianchuang , Xing Ying , Yan Jiaqiang , Mandrus David , Liu Haiwen , Xie X C , Wang Jian 
Published: July 2020

Abstract
Berry phase and Berry curvature play a key role in the development of topology in physics and do contribute to the transport properties in solid state systems. In this paper, we report the finding of novel nonzero Hall effect in topological material ZrTe5 flakes when the in-plane magnetic field is parallel and perpendicular to the current. Surprisingly, both symmetric and antisymmetric components with respect to magnetic field are detected in the in-plane Hall resistivity. Further theoretical analysis suggests that the magnetotransport properties originate from the anomalous velocity induced by Berry curvature in a tilted Weyl semimetal. Our work not only enriches the Hall family but also provides new insights into the Berry phase effect in topological materials.
Property Systems and Economic Growth in Japan, 730–1874
Authors: NAKABAYASHI Masaki , FUKAO Kyoji , TAKASHIMA Masanori , NAKAMURA Naofumi 
Published: July 2020

AbstractNew estimates on the premodern economic growth of Japan, based on more concrete evidence, have been presented. We revise the estimates of Japan’s gross domestic product (GDP) from the mid-eighth century to the mid-19th century and its population in the 12th century and describe the institutional transformations that correspond to the output changes. The revision of output and population results in updated estimates of per capita GDP for the medieval period and extension of the growth estimates in the early modern period to the annual series for 1651–1841. This study employs the techniques of quantitative inference and descriptive interpretation of the estimated performance. The findings show that: (a) Both the GDP and population significantly declined towards the 12th century, stagnated and experienced recovery from the 13th century onwards, and then continued to grow through the 17th century; (b) GDP growth accelerated in the 18th and 19th centuries; and (c) per capita GDP growth began to rise in the 13th century after a sharp decline from the 10th to 12th centuries. It continued to rise through the 16th century but declined again in the mid-17th century and finally rose again from the late 17th century onwards.
Benefit and Risk Evaluation of Biased μ-Receptor Agonist Oliceridine versus Morphine
Authors: Dahan Albert , van Dam C. Jan , Niesters Marieke , van Velzen Monique , Fossler Michael J. , Demitrack Mark A. , Olofsen Erik 
Published: July 2020

Background
To improve understanding of the respiratory behavior of oliceridine, a μ-opioid receptor agonist that selectively engages the G-protein–coupled signaling pathway with reduced activation of the β-arrestin pathway, the authors compared its utility function with that of morphine. It was hypothesized that at equianalgesia, oliceridine will produce less respiratory depression than morphine and that this is reflected in a superior utility.

Methods
Data from a previous trial that compared the respiratory and analgesic effects of oliceridine and morphine in healthy male volunteers (n = 30) were reanalyzed. A population pharmacokinetic–pharmacodynamic analysis was performed and served as basis for construction of utility functions, which are objective functions of probability of analgesia, P(analgesia), and probability of respiratory depression, P(respiratory depression). The utility function = P(analgesia ≥ 0.5) – P(respiratory depression ≥ 0.25), where analgesia ≥ 0.5 is the increase in hand withdrawal latency in the cold pressor test by at least 50%, and respiratory depression ≥ 0.25 is the decrease of the hypercapnic ventilatory response by at least 25%. Values are median ± standard error of the estimate.

Results
The two drugs were equianalgesic with similar potency values (oliceridine: 27.9 ± 4.9 ng/ml; morphine 34.3 ± 9.7 ng/ml; potency ratio, 0.81; 95% CI, 0.39 to 1.56). A 50% reduction of the hypercapnic ventilatory response by morphine occurred at an effect-site concentration of 33.7 ± 4.8 ng/ml, while a 25% reduction by oliceridine occurred at 27.4 ± 3.5 ng/ml (potency ratio, 2.48; 95% CI, 1.65 to 3.72; P < 0.01). Over the clinically relevant concentration range of 0 to 35 ng/ml, the oliceridine utility function was positive, indicating that the probability of analgesia exceeds the probability of respiratory depression. In contrast, the morphine function was negative, indicative of a greater probability of respiratory depression than analgesia.

Conclusions
These data indicate a favorable oliceridine safety profile over morphine when considering analgesia and respiratory depression over the clinical concentration range.

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Differential Ventilation Using Flow Control Valves as a Potential Bridge to Full Ventilatory Support during the COVID-19 Crisis
Authors: Levin Matthew A. , Shah Anjan , Shah Ronak , Kane Erica , Zhou George , Eisenkraft James B. , Chen Martin D. ,   for the Mount Sinai HELPS Innovate Group
Published: July 2020

Background
During the COVID-19 pandemic, ventilator sharing was suggested to increase availability of mechanical ventilation. The safety and feasibility of ventilator sharing is unknown.

Methods
A single ventilator in pressure control mode was used with flow control valves to simultaneously ventilate two patients with different lung compliances. The system was first evaluated using high-fidelity human patient simulator mannequins and then tested for 1 h in two pairs of COVID-19 patients with acute respiratory failure. Patients were matched on positive end-expiratory pressure, fractional inspired oxygen tension, and respiratory rate. Tidal volume and peak airway pressure (PMAX) were recorded from each patient using separate independent spirometers and arterial blood gas samples drawn at 0, 30, and 60 min. The authors assessed acid-base status, oxygenation, tidal volume, and PMAX for each patient. Stability was assessed by calculating the coefficient of variation.

Results
The valves performed as expected in simulation, providing a stable tidal volume of 400 ml each to two mannequins with compliance ratios varying from 20:20 to 20:90 ml/cm H2O. The system was then tested in two pairs of patients. Pair 1 was a 49-yr-old woman, ideal body weight 46 kg, and a 55-yr-old man, ideal body weight 64 kg, with lung compliance 27 ml/cm H2O versus 35 ml/cm H2O. The coefficient of variation for tidal volume was 0.2 to 1.7%, and for PMAX 0 to 1.1%. Pair 2 was a 32-yr-old man, ideal body weight 62 kg, and a 56-yr-old woman, ideal body weight 46 kg, with lung compliance 12 ml/cm H2O versus 21 ml/cm H2O. The coefficient of variation for tidal volume was 0.4 to 5.6%, and for PMAX 0 to 2.1%.

Conclusions
Differential ventilation using a single ventilator is feasible. Flow control valves enable delivery of stable tidal volume and PMAX similar to those provided by individual ventilators.

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Is Immediate Weight-Bearing Safe After Single Implant Fixation of Elderly Distal Femur Fractures?
Authors: Lieder Charles M. , Gaski Greg E. , Virkus Walter W. , Kempton Laurence B. 
Published: July 2020

Objectives:
To compare early complications in elderly patients with extra-articular distal femur fractures (DFFs) allowed to weight-bear as tolerated (WBAT) immediately versus patients prescribed initial touchdown weight-bearing (TDWB).

Design:
Retrospective cohort study.

Setting:
Level 1 academic trauma center.

Patients:
One hundred thirty-five patients 60 years or older who underwent surgical fixation of an extra-articular DFF, including the OTA/AO fracture classification of 33-A1-3, and periprosthetic fractures with a stable knee prosthesis (Lewis and Rorabeck type I or II) with at least 6 months follow-up.

Intervention:
Immediate WBAT or TDWB after surgical fixation of an extra-articular DFF with either an intramedullary nail or locked plate.

Main Outcome Measurements:
The primary outcome was a major adverse event within the first 6 months, defined as (1) early fixation failure or change in alignment leading to reoperation, (2) nonunion, or (3) deep infection. Secondary outcomes included postoperative inpatient length of stay, discharge disposition (secondary facility vs. home), malunion, mortality, and patient-reported outcomes.

Results:
The rate of early adverse events requiring reoperation was similar between the WBAT group (6, 10.7%) and the TDWB group (15, 19.0%; P = 0.23). There was no difference between groups with respect to length of stay, discharge disposition, malunion, and patient-reported outcomes.

Conclusions:
This study supports allowing carefully selected elderly patients, based on surgeon preference, to immediately weight-bear after operative fixation of an extra-articular DFF regardless of implant choice.

Level of Evidence:
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Percutaneous Tracheostomy With Apnea During Coronavirus Disease 2019 Era: A Protocol and Brief Report of Cases
Authors: Niroula Abesh , Van Nostrand Keriann M. , Khullar Onkar V. , Force Seth , Jaber Wissam S. , Sardi Alejandro H. , Berkowitz David M. 
Published: July 2020

Objective:
To assess feasibility of modified protocol during percutaneous tracheostomy in coronavirus disease 2019 pandemic era.

Design:
A retrospective review of cohort who underwent percutaneous tracheostomy with modified protocol.

Settings:
Medical, surgical, and neurologic ICUs.

Subjects:
Patients admitted in medical, surgical, and neurologic units with prolonged need of mechanical ventilation or inability to liberate from the ventilator.

Interventions:
A detailed protocol was written. Steps were defined to be performed before apnea and during apnea. A feasibility study of 28 patients was conducted. The key aerosol-generating portions of the procedure were performed with the ventilator switched to standby mode with the patient apneic.

Measurements and Main Results:
Data including patient demographics, primary diagnosis, age, body mass index, and duration of apnea time during the tracheostomy were collected. Average ventilator standby time (apnea) during the procedure was 238 seconds (3.96 min) with range 149 seconds (2.48 min) to 340 seconds (5.66 min). Single-use (disposable) bronchoscopes (Ambu A/S [Ballerup, Denmark] or Glidescope [Verathon, Inc., Bothell, WA]) were used during all procedures except in nine. No desaturation events occurred during any procedure.

Conclusions:
Percutaneous tracheostomy performed with apnea protocol may help minimize aerosolization, reducing risk of exposure of coronavirus disease 2019 to staff. It can be safely performed with portable bronchoscopes to limit staff and minimize the surfaces requiring disinfection post procedure.