bluuebunny/crossref_metadata_2025_split huggingface dataset:
Skin Swabbing for Staphylococcus aureus–Targeting Phages
Authors: Duplessis Christopher , Luke Thomas C , Watters Chase , Alcorta Yolanda , Biswas Biswajit 
Published: June 2021

ABSTRACTIntroductionStaphylococcus aureus (SA) is a major human bacterial pathogen increasingly refractory to antibiotics. Given the dearth of novel antibiotics in the developmental pipeline, we require concerted efforts at optimizing novel antimicrobial approaches. One promising option is the utilization of bacteriophage (phage) therapy, which has been resurrected as a viable clinical therapeutic. Specifically, an expanded library of phages targeting SA is desired. We surmised that SA-targeting phages would be readily accessible as a major component of the cutaneous microbiome. Specifically, we sought to discern if easily accessible (convenient) and discrete anatomic locations, including the nares, axilla, fingernails, toenails, and web spaces, could provide intact phages via a noninvasive, expedient procedure involving swabbing.MethodsOne hundred subjects participated in systematic skin swab specimen collections. Pooled samples were subject to phage harvesting utilizing the soft agar overlay technique. The approval was secured from the Naval Medical Research Center Institutional Review Board (NMRC 2018.0004 FWA00000152). We utilized the same procedures from known samples containing SA-targeting phages. As another positive control, we employed the same swab and acquired samples from an active wound infection.ResultsAs anticipated, there were no adverse events, and the procedure was successfully implemented within the projected 10-minute duration. No phages were identified exploiting this methodology. Positive controls from various environmental samples identified SA-targeting phages as did the wound effluent sample.ConclusionsSkin swabbing at multiple anatomic sites from 100 adults yielded insufficient biomass for phage recovery. The negative results provide helpful information for future phage isolation attempts. The lessons learned on why this study failed to isolate phages can be easily utilized by others. With a desire to increase our SA-targeting phage library in pursuit of future clinical trials, and acknowledging the paucity of these phages accessible via traditional recovery from environmental sources, we will next acquire large volumes of wound effluent from confirmed infected wounds with SA to optimize the biomass for phage recovery.
Escaping the Cycle
Authors: Gallow J Dmitri 
Published: June 2021

Abstract
I present a decision in which causal decision theory appears to violate the independence of irrelevant alternatives (IIA) and normal-form extensive-form equivalence (NEE). I show that these violations lead to exploitable behaviour and long-run poverty. These consequences appear damning, but I urge caution. This decision should lead causalists to a better understanding of what it takes for a decision between some collection of options to count as a subdecision of a decision between a larger collection of options. And with this better understanding of subdecisions in hand, causalists will not violate IIA or NEE. This decision will also teach causalists that, in sequential decisions, a rational agent may be led to make a series of choices which are causally dominated by some other sequence of choices they could have made instead. I will encourage causalists to recognize this as an intrapersonal tragedy of the commons.
Dense molecular gas properties on 100 pc scales across the disc of NGC 3627
Authors: Bešlić I , Barnes A T , Bigiel F , Puschnig J , Pety J , Herrera Contreras C , Leroy A K , Usero A , Schinnerer E , Meidt S E , Emsellem E , Hughes A , Faesi C , Kreckel K , Belfiore F M C , Chevance M , den Brok J S , Eibensteiner C , Glover S C O , Grasha K , Jimenez-Donaire M J , Klessen R S , Kruijssen J M D , Liu D , Pessa I , Querejeta M , Rosolowsky E , Saito T , Santoro F , Schruba A , Sormani M C , Williams T G 
Published: June 2021

ABSTRACT
It is still poorly constrained how the densest phase of the interstellar medium varies across galactic environment. A large observing time is required to recover significant emission from dense molecular gas at high spatial resolution, and to cover a large dynamic range of extragalactic disc environments. We present new NOrthern Extended Millimeter Array (NOEMA) observations of a range of high critical density molecular tracers (HCN, HNC, HCO+) and CO isotopologues (13CO, C18O) towards the nearby (11.3 Mpc) strongly barred galaxy NGC 3627. These observations represent the current highest angular resolution (1.85 arcsec; 100 pc) map of dense gas tracers across a disc of a nearby spiral galaxy, which we use here to assess the properties of the dense molecular gas, and their variation as a function of galactocentric radius, molecular gas, and star formation. We find that the HCN(1–0)/CO(2–1) integrated intensity ratio does not correlate with the amount of recent star formation. Instead, the HCN(1–0)/CO(2–1) ratio depends on the galactic environment, with differences between the galaxy centre, bar, and bar-end regions. The dense gas in the central 600 pc appears to produce stars less efficiently despite containing a higher fraction of dense molecular gas than the bar ends where the star formation is enhanced. In assessing the dynamics of the dense gas, we find the HCN(1–0) and HCO+(1–0) emission lines showing multiple components towards regions in the bar ends that correspond to previously identified features in CO emission. These features are cospatial with peaks of Hα emission, which highlights that the complex dynamics of this bar-end region could be linked to local enhancements in the star formation.
Discovery and modelling of broad-scale plasma lensing in black-widow pulsar J2051 − 0827
Authors: Lin F X , Main R A , Verbiest J P W , Kramer M , Shaifullah G 
Published: June 2021

ABSTRACT
We report on an unusually bright observation of PSR J2051 − 0827 recorded during a regular monitoring campaign of black-widow pulsar systems with the Effelsberg 100-m telescope. Through fortunate coincidence, a particularly bright scintillation maximum is simultaneous with the eclipse by the companion, enabling precise measurements of variations in the flux density, dispersion measure (DM), and scattering strength throughout the eclipse. The flux density is highly variable throughout the eclipse, with a peak 1.7 times the average away from the eclipse, and yet does not significantly decrease on average. We recover the flux density variations from the measured DM variations using geometric optics, with a relative velocity as the only free parameter. We measure an effective velocity of 470 ± 10 km s−1, consistent with the relative orbital motion of the companion, suggesting that the outflow velocity of the lensing material is low, or is directly along the line of sight. The $2{{\ \rm per\ cent}}$ uncertainty on the effective velocity is a formal error; systematics related to our current model are likely to dominate, and we detail several extensions to the model to be considered in a full treatment of lensing. This is a demonstration of the causal link between DM and lensing; the flux density variations can be predicted directly through the derivatives of DM. Going forward, this approach can be applied to investigate the dynamics of other eclipsing systems, and to investigate the physical nature of scintillation and lensing in the ionized interstellar medium.
An investigation of the causal relationship between sunspot groups and coronal mass ejections by determining source active regions
Authors: Raheem Abd-ur , Cavus Huseyin , Coban Gani Caglar , Kinaci Ahmet Cumhur , Wang Haimin , Wang Jason T L 
Published: June 2021

ABSTRACT
Although the source active regions of some coronal mass ejections (CMEs) were identified in CME catalogues, vast majority of CMEs do not have an identified source active region. We propose a method that uses a filtration process and machine learning to identify the sunspot groups associated with a large fraction of CMEs and compare the physical parameters of these identified sunspot groups with properties of their corresponding CMEs to find mechanisms behind the initiation of CMEs. These CMEs were taken from the Coordinated Data Analysis Workshops (CDAW) data base hosted at NASA’s website. The Helioseismic and Magnetic Imager (HMI) Active Region Patches (HARPs) were taken from the Stanford University’s Joint Science Operations Center (JSOC) data base. The source active regions of the CMEs were identified by the help of a custom filtration procedure and then by training a long short-term memory network (LSTM) to identify the patterns in the physical magnetic parameters derived from vector and line-of-sight magnetograms. The neural network simultaneously considers the time series data of these magnetic parameters at once and learns the patterns at the onset of CMEs. This neural network was then used to identify the source HARPs for the CMEs recorded from 2011 till 2020. The neural network was able to reliably identify source HARPs for 4895 CMEs out of 14 604 listed in the CDAW data base during the aforementioned period.
MIGHTEE-HI: discovery of an H i-rich galaxy group atz = 0.044 with MeerKAT
Authors: Ranchod Shilpa , Deane Roger P , Ponomareva Anastasia A , Blecher Tariq , Frank Bradley S , Jarvis Matt J , Maddox Natasha , Mulaudzi Wanga , Glowacki Marcin , Hess Kelley M , Tudorache Madalina , Verdes-Montenegro Lourdes , Adams Nathan J , Bowler Rebecca A A , Collier Jordan D , Taylor Russ 
Published: June 2021

ABSTRACTWe present the serendipitous discovery of a galaxy group in the XMM-LSS field with MIGHTEE Early Science observations. 20 galaxies are detected in H i in this z ∼ 0.044 group, with a 3σ column density sensitivity of $N_{\rm H\, \small {I}} = 1.6\times 10^{20}\, \mathrm{cm}^{-2}$. This group has not been previously identified, despite residing in a well-studied extragalactic legacy field. We present spatially resolved H i total intensity and velocity maps for each of the objects which reveal environmental influence through disturbed morphologies. The group has a dynamical mass of $\log_{10} (M_{\rm dyn}/\mathrm{M}_\odot) = 12.32$, and is unusually gas-rich, with an H i-to-stellar mass ratio of $\log _{10}(f_{\rm H\, \small {I}}^\mathrm{*}) = -0.2$, which is 0.7 dex greater than expected. The group’s high H i content, spatial, velocity, and identified galaxy type distributions strongly suggest that it is in the early stages of its assembly. The discovery of this galaxy group is an example of the importance of mapping spatially resolved H i in a wide range of environments, including galaxy groups. This scientific goal has been dramatically enhanced by the high sensitivity, large field-of-view, and wide instantaneous bandwidth of the MeerKAT telescope.
The link between gas and stars in the S254–S258 star-forming region
Authors: Ladeyschikov D A , Kirsanova M S , Sobolev A M , Thomasson M , Ossenkopf-Okada V , Juvela M , Khaibrakhmanov S A , Popova E A 
Published: June 2021

ABSTRACT
The paper aims to study relation between the distributions of the young stellar objects (YSOs) of different ages and the gas-dust constituents of the S254–S258 star formation complex. This is necessary to study the time evolution of the YSO distribution with respect to the gas and dust compounds that are responsible for the birth of the young stars. For this purpose, we use correlation analysis between different gas, dust, and YSO tracers. We compared the large-scale CO, HCO+, near-IR extinction, and far-IR Herschel maps with the density of YSOs of the different evolutionary classes. The direct correlation analysis between these maps was used together with the wavelet-based spatial correlation analysis. This analysis reveals a much tighter correlation of the gas-dust tracers with the distribution of class I YSOs than with that of class II YSOs. We argue that class I YSOs that were initially born in the central bright cluster S255-IR (both N and S parts) during their evolution to class II stage (∼2 Myr) had enough time to travel through the whole S254–S258 star formation region. Given that the region contains several isolated YSO clusters, the evolutionary link between these clusters and the bright central S255-IR (N and S) cluster can be considered. Despite the complexity of the YSO cluster formation in the non-uniform medium, the clusters of class II YSOs in the S254-258 star formation region can contain objects born in the different locations of the complex.
Reionization and galaxy inference from the high-redshift Ly α forest
Authors: Qin Yuxiang , Mesinger Andrei , Bosman Sarah E I , Viel Matteo 
Published: June 2021

ABSTRACTThe transmission of Lyman α (Ly α) in the spectra of distant quasars depends on the density, temperature, and ionization state of the intergalactic medium. Therefore, high-redshift (z &gt; 5) Ly α forests could be invaluable in studying the late stages of the epoch of reionization (EoR), as well as properties of the sources that drive it. Indeed, high-quality quasar spectra have now firmly established the existence of large-scale opacity fluctuations at z &gt; 5, whose physical origins are still debated. Here, we introduce a Bayesian framework capable of constraining the EoR and galaxy properties by forward-modelling the high-z Ly α forest. Using priors from galaxy and cosmic microwave background observations, we demonstrate that the final overlap stages of the EoR (when &gt;95 per cent of the volume was ionized) should occur at z &lt; 5.6, in order to reproduce the large-scale opacity fluctuations seen in forest spectra. However, it is the combination of patchy reionization and the inhomogeneous ultraviolet background that produces the longest Gunn–Peterson troughs. Ly α forest observations tighten existing constraints on the characteristic ionizing escape fraction of galaxies, with the combined observations suggesting $f_{\rm esc} \approx 7^{+4}_{-3}$ per cent, and disfavouring a strong evolution with the galaxy’s halo (or stellar) mass.
The role of gas kinematics in setting metallicity gradients at high redshift
Authors: Sharda Piyush , Wisnioski Emily , Krumholz Mark R , Federrath Christoph 
Published: June 2021

ABSTRACT
In this work, we explore the diversity of ionized gas kinematics (rotational velocity vϕ and velocity dispersion σg) and gas-phase metallicity gradients at 0.1 ≤ z ≤ 2.5 using a compiled data set of 74 galaxies resolved with ground-based integral field spectroscopy. We find that galaxies with the highest and the lowest σg have preferentially flat metallicity gradients, whereas those with intermediate values of σg show a large scatter in the metallicity gradients. Additionally, steep negative gradients appear almost only in rotation-dominated galaxies (vϕ/σg &gt; 1), whereas most dispersion-dominated galaxies show flat gradients. We use our recently developed analytical model of metallicity gradients to provide a physical explanation for the shape and scatter of these observed trends. In the case of high σg, the inward radial advection of gas dominates over metal production and causes efficient metal mixing, thus giving rise to flat gradients. For low σg, it is the cosmic accretion of metal-poor gas diluting the metallicity that gives rise to flat gradients. Finally, the reason for intermediate σg showing the steepest negative gradients is that both inward radial advection and cosmic accretion are weak as compared to metal production, which leads to the creation of steeper gradients. The larger scatter at intermediate σg may be due in part to preferential ejection of metals in galactic winds, which can decrease the strength of the production term. Our analysis shows how gas kinematics play a critical role in setting metallicity gradients in high-redshift galaxies.
The metal-poor dwarf irregular galaxy candidate next to Mrk 1172
Authors: Lassen Augusto E , Riffel Rogerio , Chies-Santos Ana L , Johnston Evelyn , Häußler Boris , Azevedo Gabriel M , Ruschel-Dutra Daniel , Riffel Rogemar A 
Published: June 2021

ABSTRACT
In this work, we characterize the properties of the object SDSS J020536.84−081424.7, an extended nebular region with projected extension of 14 × 14 kpc2 in the line of sight of the ETG Mrk 1172, using unprecedented spectroscopic data from MUSE. We perform a spatially resolved stellar population synthesis and estimate the stellar mass for both Mrk 1172 (1 × 1011 M⊙) and our object of study (3 × 109 M⊙). While the stellar content of Mrk 1172 is dominated by an old (∼10 Gyr) stellar population, the extended nebular emission has its light dominated by young to intermediate age populations (from ∼100 Myr to ∼1 Gyr) and presents strong emission lines such as H β; [O iii] λλ4959, 5007 Å; H α; [N ii] λλ6549, 6585 Å; and [S ii] λλ6717, 6732 Å. Using these emission lines, we find that it is metal poor (with Z ∼ 1/3 Z⊙, comparable to the LMC) and is actively forming stars (0.70 M⊙ yr−1), especially in a few bright clumpy knots that are readily visible in H α. The object has an ionized gas mass ≥3.8 × 105 M⊙. Moreover, the motion of the gas is well described by a gas in circular orbit in the plane of a disc and is being affected by interaction wtih Mrk 1172. We conclude that SDSS J020536.84−081424.7 is most likely a dwarf irregular galaxy (the dIGal).
Optimal survey parameters: Ly αand H αintensity mapping for synergy with the 21-cm signal during reionization
Authors: Heneka Caroline , Cooray Asantha 
Published: June 2021

ABSTRACTIntensity mapping (IM) of multiple emission lines is emerging as a new branch to astronomy, to probe both properties of ionizing sources and the medium between, in particular the intergalactic medium. For Epoch of Reionization (EoR) studies, both multiline experiments and analysis methods are still in their infancy. Here we explore optimal survey parameters for Ly α (and H α) IM up to high redshifts of reionization, and requirements for optimized synergy with 21-cm experiments. We investigate line sensitivity, spectral resolution, and detector pixel size requirements for optimal (high signal-to-noise ratio, S/N) mission output. Power and cross-power spectra in a fiducial setup are derived, as are mock intensity maps. For line power spectrum measurements, a cumulative S/N of O(103), and for respective cross-spectra with SKA 21-cm observations of O(10) to O(102) are possible per redshift bin around the mid-point of reionization. These high S/N tomographic measurements are in reach for line sensitivities &gt;8 × 10−18 erg s−1 sr−1 Hz−1, spectral resolution R &gt; 250 and detector pixel sizes $\lt 2\,$ arcsec; all three requirements are met by the proposed Cosmic Dawn Intensity Mapper (CDIM). For CDIM, similar S/N values are in reach for H α. Already the planned NASA mission SPHEREx will detect during the EoR Ly α autopower and cross-power with 21-cm (SKA and HERA-type), for sensitivities &gt;10−18 erg s−1 sr−1 Hz−1 in a moderate 21-cm foreground scenario (&gt;10−17 erg s−1 sr−1 Hz−1 in an optimistic scenario). We advocate for IR missions in flavour of CDIM for a leap in IM and finish by providing a cookbook for successful multiline IM during the EoR.
iCOM formation from radical chemistry: a mechanistic study from cryogenic matrix coupled with IR and EPR spectroscopies
Authors: Gutiérrez-Quintanilla A , Layssac Y , Butscher T , Henkel S , Tsegaw Y A , Grote D , Sander W , Borget F , Chiavassa T , Duvernay F 
Published: June 2021

ABSTRACT
Interstellar complex organic molecules (iCOMs) have been identified in different interstellar environments including star forming regions as well as cold dense molecular clouds. Laboratory studies show that iCOMs can be formed either in gas phase or in the solid state, on icy grains, from ‘non-energetic’ (atom-addition/abstraction) or energetic (UV-photon, particle bombardments) processes. In this contribution, using a new experimental approach mixing matrix isolation technique, mass spectrometry, and infrared and EPR spectroscopies, we want to investigate the COM formation at 35 K from a complex mixture of ground state radicals trying to draw a general reaction scheme. We photolyse (121 nm) CH3OH diluted in Ar at low temperature (below 15 K) to generate $\mathrm{H^.CO}$, $\mathrm{HO^.CO}$, $\mathrm{^.CH_2OH}$, $\mathrm{CH_3O^.}$, $\mathrm{^.OH}$, and $\mathrm{^.CH_3}$ radicals and ‘free’ H-atoms within the matrix. Radicals have been identified using infrared and EPR spectroscopies. With the disappearance of the Ar matrix (at 35 K), these unstable species are then free to react, forming new species in a solid film. Some recombination products have been detected using infrared spectroscopy and mass spectrometry in the solid film after Ar removal, namely methyl formate (CH3OCHO), glycolaldehyde (HOCH2CHO), ethylene glycol (HOCH2CH2OH), glyoxal (CHOCHO), ethanol (CH3CH2OH), formic acid (HCOOH), dimethyl ether (CH3OCH3), methoxymethanol (CH3OCH2OH), and CH4O2 isomers (methanediol and/or methyl hydroperoxide). The detected molecules are fully consistent with the radicals detected and strongly support the solid state scenario of iCOM formation in interstellar ices based on radical–radical recombination. We then discuss astrophysical implications of the radical pathways on the observed gas phase iCOMs.
Ultraviolet line profiles of slowly rotating massive star winds using the ‘analytic dynamical magnetosphere’ formalism
Authors: Erba C , David-Uraz A , Petit V , Hennicker L , Fletcher C , Fullerton A W , Nazé Y , Sundqvist J , ud-Doula A 
Published: June 2021

ABSTRACT
Recent large-scale spectropolarimetric surveys have established that a small but significant percentage of massive stars host stable, surface dipolar magnetic fields with strengths on the order of kG. These fields channel the dense, radiatively driven stellar wind into circumstellar magnetospheres, whose density and velocity structure can be probed using ultraviolet (UV) spectroscopy of wind-sensitive resonance lines. Coupled with appropriate magnetosphere models, UV spectroscopy provides a valuable way to investigate the wind–field interaction, and can yield quantitative estimates of the wind parameters of magnetic massive stars. We report a systematic investigation of the formation of UV resonance lines in slowly rotating magnetic massive stars with dynamical magnetospheres. We pair the analytic dynamical magnetosphere (ADM) formalism with a simplified radiative transfer technique to produce synthetic UV line profiles. Using a grid of models, we examine the effect of magnetosphere size, the line strength parameter, and the cooling parameter on the structure and modulation of the line profile. We find that magnetic massive stars uniquely exhibit redshifted absorption at most viewing angles and magnetosphere sizes, and that significant changes to the shape and variation of the line profile with varying line strengths can be explained by examining the individual wind components described in the ADM formalism. Finally, we show that the cooling parameter has a negligible effect on the line profiles.