bluuebunny/crossref_metadata_2025_split huggingface dataset:
Periodic stellar variability from almost a million NGTS light curves
Authors: Briegal Joshua T , Gillen Edward , Queloz Didier , Hodgkin Simon , Acton Jack S , Anderson David R , Armstrong David J , Battley Matthew P , Bayliss Daniel , Burleigh Matthew R , Bryant Edward M , Casewell Sarah L , Costes Jean C , Eigmüller Philipp , Gill Samuel , Goad Michael R , Günther Maximilian N , Henderson Beth A , Jackman James A G , Jenkins James S , Kreutzer Lars T , Moyano Maximiliano , Lendl Monika , Smith Gareth D , Tilbrook Rosanna H , Watson Christopher A , West Richard G , Wheatley Peter J 
Published: April 2022

ABSTRACT
We analyse 829 481 stars from the Next Generation Transit Survey (NGTS) to extract variability periods. We utilize a generalization of the autocorrelation function (the G-ACF), which applies to irregularly sampled time series data. We extract variability periods for 16 880 stars from late-A through to mid-M spectral types and periods between ∼0.1 and 130 d with no assumed variability model. We find variable signals associated with a number of astrophysical phenomena, including stellar rotation, pulsations, and multiple-star systems. The extracted variability periods are compared with stellar parameters taken from Gaia DR2, which allows us to identify distinct regions of variability in the Hertzsprung–Russell Diagram. We explore a sample of rotational main-sequence objects in period-colour space, in which we observe a dearth of rotation periods between 15 and 25 d. This ‘bi-modality’ was previously only seen in space-based data. We demonstrate that stars in sub-samples above and below the period gap appear to arise from a stellar population not significantly contaminated by excess multiple systems. We also observe a small population of long-period variable M-dwarfs, which highlight a departure from the predictions made by rotational evolution models fitted to solar-type main-sequence objects. The NGTS data spans a period and spectral type range that links previous rotation studies such as those using data from Kepler, K2, and MEarth.
Helium-like X-ray line complexes show that the hottest plasma on the O supergiant ζ Puppis is in its wind
Authors: Cohen David H , Overdorff Ariel M , Leutenegger Maurice A , Gagné Marc , Petit Véronique , David-Uraz Alexandre 
Published: April 2022

ABSTRACT
We present an analysis of Chandra grating spectra of key helium-like line complexes to put constraints on the location with respect to the photosphere of the hottest (T ≳ 6 × 106 K) plasma in the wind of the O supergiant ζ Pup and to explore changes in the 18 yr between two sets of observations of this star. We fit two models – one empirical and one wind-shock-based – to the S xv, Si xiii, and Mg xi line complexes and show that an origin in the wind flow, above r ≈ 1.5 R*, is strongly favoured over an origin less than 0.3 R* above the photosphere (r ≲ 1.3 R*), especially in the more recent, very long-exposure data set. There is a modest increase in the line and continuum fluxes, line widths, wind absorption signatures, and of the hot plasma’s distance from the photosphere in the 18 yr since the first Chandra grating observation of ζ Pup. Both modes of modelling include the effects of dielectronic recombination satellite emission line blending on the helium-like complexes – the first time this has been accounted for in the analysis of He-like line ratios in O stars.
Rapidly quenched galaxies in the Simba cosmological simulation and observations
Authors: Zheng Yirui , Dave Romeel , Wild Vivienne , Montero Francisco Rodríguez 
Published: April 2022

ABSTRACT
Galaxies with little star formation are found to have quenched over a variety of time-scales, which provides insights into the physical mechanisms responsible. Here, we examine the population of rapidly quenched galaxies (RQGs) in the Simba cosmological hydrodynamic simulation at 0.5 &lt; z &lt; 2, and compare them directly to observed post-starburst galaxies in the UKIDSS Ultra Deep Survey (UDS) via their colour distributions and mass functions. We find that the fraction of quiescent galaxies that are rapidly quenched in Simba at z = 1 is 59 ± 3 per cent, contributing 48 ± 5 per cent to the total mass of the red sequence, which is at the upper end of the ∼25–50 per cent derived from the UDS. A similar ‘downsizing’ of RQGs is observed in both Simba and the UDS, with RQGs at higher redshift having a higher average mass. However, Simba produces too many RQGs at 1 &lt; zq &lt; 1.5 and too few low mass RQGs at 0.5 &lt; zq &lt; 1. Comparing colour distributions further suggests discrepancies in star formation and/or chemical enrichment histories, including an absence of short, intense starbursts in Simba. Our results will help inform the next generation of galaxy evolution models, particularly with respect to the quenching mechanisms employed.
Collisional excitation of HD by H
Authors: Desrousseaux Benjamin , Coppola Carla Maria , Lique François 
Published: April 2022

ABSTRACT
The HD molecule plays an important role in many astrophysical environments. Accurate modelling of the gas cooling induced by HD and its abundance in such media requires a proper modelling of its excitation by both radiative and collisional processes. Reliable state-to-state collisional rate coefficients in extended temperature regimes are then essential to allow for the description of different astrophysical environments where deviations from local thermodynamic equilibrium regime can occur. Here, we report exact quantum time-independent reactive scattering calculations for the rovibrational excitation of HD by H. Rate coefficients are computed for temperatures up to 5000 K and transitions between all rovibrational states with internal energies up to 14 000 cm−1. Previous results neglecting reactive and exchange channels of the colliding system are compared to the new ones and significant differences are found. The present work represent a big step in the complete description of the HD–H collisional system, in terms of rovibrational states considered, temperature range explored and accuracy. Hence, we recommend the use of the new HD–H collisional data presented here to accurately model the astrophysical environments where HD plays a role.
Different molecular filament widths as tracers of accretion on to filaments
Authors: Gómez Gilberto C , Walsh Catherine , Palau Aina 
Published: April 2022

ABSTRACT
We explore how dense filament widths, when measured using different molecular species, may change as a consequence of gas accretion towards the filament. As a gas parcel falls into the filament, it will experience different density, temperature, and extinction values. The rate at which this environment changes will affect differently the abundance of different molecules. So, a molecule that forms quickly will better reflect the local physical conditions a gas parcel experiences than a slower forming molecule. Since these differences depend on how the respective time-scales compare, the different molecular distributions should reflect how rapidly the environment changes, i.e. the accretion rate towards the filament. We find that the filament widths measured from time-dependent abundances for C2H, CO, CN, CS, and C3H2 are the most sensitive to this effect. This is because these molecules are the ones presenting also the wider filament widths. On the contrary, molecules such as N2H+, NH3, H2CO, HNC, and CH3OH are not so sensitive to accretion and present the narrowest filament widths. We propose that ratios of filament widths for different tracers could be a useful tool to estimate the accretion rate on to the filament.
The secular growth of bars revealed by flat (peak + shoulders) density profiles
Authors: Anderson Stuart Robert , Debattista Victor P , Erwin Peter , Liddicott David J , Deg Nathan , Beraldo e Silva Leandro 
Published: April 2022

ABSTRACT
The major-axis density profiles of bars are known to be either exponential or ‘flat’. We develop an automated non-parametric algorithm to detect flat profiles and apply it to a suite of simulations (with and without gas). We demonstrate that flat profiles are a manifestation of a bar’s secular growth, producing a ‘shoulder’ region (an overdensity above an exponential) in its outskirts. Shoulders are not present when bars form, but develop as the bar grows. If the bar does not grow, shoulders do not form. Shoulders are often accompanied by box/peanut bulges, but develop separately from them and are independent tracers of a bar’s growth. They can be observed at a wide range of viewing orientations with only their slope varying significantly with inclination. We present evidence that shoulders are produced by looped x1 orbits. Since the growth rate of the bar moderately correlates with the growth rate of the shoulder strength, these orbits are probably recently trapped. Shoulders therefore are evidence of bar growth. The properties of the shoulders do not, however, establish the age of a bar, because secondary buckling or strong spirals may destroy shoulders, and also because shoulders do not form if the bar does not grow much. In particular, our results show that an exponential profile is not necessarily an indication of a young bar.
Discoveries and timing of pulsars in NGC 6440
Authors: Vleeschower L , Stappers B W , Bailes M , Barr E D , Kramer M , Ransom S , Ridolfi A , Venkatraman Krishnan V , Possenti A , Keith M J , Burgay M , Freire P C C , Spiewak R , Champion D J , Bezuidenhout M C , Niţu I C , Chen W , Parthasarathy A , DeCesar M E , Buchner S , Stairs I H , Hessels J W T 
Published: April 2022

ABSTRACT
Using the MeerKAT radio telescope, a series of observations have been conducted to time the known pulsars and search for new pulsars in the globular cluster NGC 6440. As a result, two pulsars have been discovered, NGC 6440G and NGC 6440H, one of which is isolated and the other a non-eclipsing (at frequencies above 962 MHz) ‘Black Widow’, with a very low mass companion (Mc &gt; 0.006 M⊙). It joins the other binary pulsars discovered so far in this cluster that all have low companion masses (Mc &lt; 0.30 M⊙). We present the results of long-term timing solutions obtained using data from both Green Bank and MeerKAT telescopes for these two new pulsars and an analysis of the pulsars NGC 6440C and NGC 6440D. For the isolated pulsar NGC 6440C, we searched for planets using a Markov chain Monte Carlo technique. We find evidence for significant unmodelled variations but they cannot be well modelled as planets nor as part of a power-law red-noise process. Studies of the eclipses of the ‘Redback’ pulsar NGC 6440D at two different frequency bands reveal a frequency dependence with longer and asymmetric eclipses at lower frequencies (962–1283 MHz).
Predicting the black hole mass and correlations in X-ray reverberating AGNs using neural networks
Authors: Chainakun P , Fongkaew I , Hancock S , Young A J 
Published: April 2022

ABSTRACT
We develop neural network models to predict the black hole mass using 22 reverberating active galactic nucleus (AGN) samples in the XMM–Newton archive. The model features include the fractional excess variance (Fvar) in 2–10 keV band, Fe-K lag amplitude, 2–10 keV photon counts, and redshift. We find that the prediction accuracy of the neural network model is significantly higher than what is obtained from the traditional linear regression method. Our predicted mass can be confined within ±(2–5) per cent of the true value, suggesting that the neural network technique is a promising and independent way to constrain the black hole mass. We also apply the model to 21 non-reverberating AGNs to rule out their possibility to exhibit the lags (some have too small mass and Fvar, while some have too large mass and Fvar that contradict the Fvar–lag–mass relation in reverberating AGNs). We also simulate 3200 reverberating AGN samples using the multifeature parameter space from the neural network model to investigate the global relations if the number of reverberating AGNs increases. We find that the Fvar–mass anticorrelation is likely stronger with increasing number of newly discovered reverberating AGNs. Contrarily, to maintain the lag–mass scaling relation, the tight anticorrelation between the lag and Fvar must preserve. In an extreme case, the lag–mass correlation coefficient can significantly decrease and, if observed, may suggest the extended corona framework where their observed lags are more driven by the coronal property rather than geometry.
OBIF: an omics-based interaction framework to reveal molecular drivers of synergy
Authors: Pantaleón García Jezreel , Kulkarni Vikram V , Reese Tanner C , Wali Shradha , Wase Saima J , Zhang Jiexin , Singh Ratnakar , Caetano Mauricio S , Kadara Humam , Moghaddam Seyed Javad , Johnson Faye M , Wang Jing , Wang Yongxing , Evans Scott E 
Published: April 2022

Abstract
Bioactive molecule library screening may empirically identify effective combination therapies, but molecular mechanisms underlying favorable drug–drug interactions often remain unclear, precluding further rational design. In the absence of an accepted systems theory to interrogate synergistic responses, we introduce Omics-Based Interaction Framework (OBIF) to reveal molecular drivers of synergy through integration of statistical and biological interactions in synergistic biological responses. OBIF performs full factorial analysis of feature expression data from single versus dual exposures to identify molecular clusters that reveal synergy-mediating pathways, functions and regulators. As a practical demonstration, OBIF analyzed transcriptomic and proteomic data of a dyad of immunostimulatory molecules that induces synergistic protection against influenza A and revealed unanticipated NF-κB/AP-1 cooperation that is required for antiviral protection. To demonstrate generalizability, OBIF analyzed data from a diverse array of Omics platforms and experimental conditions, successfully identifying the molecular clusters driving their synergistic responses. Hence, unlike existing synergy quantification and prediction methods, OBIF is a phenotype-driven systems model that supports multiplatform interrogation of synergy mechanisms.
Hypothetical generalized framework for a new imaging endpoint of therapeutic activity in early phase clinical trials in brain tumors
Authors: Ellingson Benjamin M , Gerstner Elizabeth R , Lassman Andrew B , Chung Caroline , Colman Howard , Cole Patricia E , Leung David , Allen Joshua E , Ahluwalia Manmeet S , Boxerman Jerrold , Brown Matthew , Goldin Jonathan , Nduom Edjah , Hassan Islam , Gilbert Mark R , Mellinghoff Ingo K , Weller Michael , Chang Susan , Arons David , Meehan Clair , Selig Wendy , Tanner Kirk , Alfred Yung W K , van den Bent Martin , Wen Patrick Y , Cloughesy Timothy F 
Published: April 2022

Abstract
Imaging response assessment is a cornerstone of patient care and drug development in oncology. Clinicians/clinical researchers rely on tumor imaging to estimate the impact of new treatments and guide decision making for patients and candidate therapies. This is important in brain cancer, where associations between tumor size/growth and emerging neurological deficits are strong. Accurately measuring the impact of a new therapy on tumor growth early in clinical development, where patient numbers are small, would be valuable for decision making regarding late-stage development activation. Current attempts to measure the impact of a new therapy have limited influence on clinical development, as determination of progression, stability or response does not currently account for individual tumor growth kinetics prior to the initiation of experimental therapies. Therefore, we posit that imaging-based response assessment, often used as a tool for estimating clinical effect, is incomplete as it does not adequately account for growth trajectories or biological characteristics of tumors prior to the introduction of an investigational agent. Here, we propose modifications to the existing framework for evaluating imaging assessment in primary brain tumors that will provide a more reliable understanding of treatment effects. Measuring tumor growth trajectories prior to a given intervention may allow us to more confidently conclude whether there is an anti-tumor effect. This updated approach to imaging-based tumor response assessment is intended to improve our ability to select candidate therapies for later-stage development, including those that may not meet currently sought thresholds for “response” and ultimately lead to identification of effective treatments.
N-heterocyclic carbene-stabilized metal nanoparticles within porous organic cages for catalytic application
Authors: Liu Tong , Bai Sha , Zhang Le , Hahn F Ekkehardt , Han Ying-Feng 
Published: April 2022

AbstractTuning the surface-embellishing ligands of metal nanoparticles (NPs) is a powerful strategy to modulate their morphology and surface electronic and functional features, impacting their catalytic activity and selectivity. In this work, we report the design and synthesis of a polytriazolium organic cage PIC-T, capable of stabilizing PdNPs within its discrete cavity. The obtained material (denoted Pd@PCC-T) is highly durable and monodispersed with narrow particle-size distribution of 2.06 ± 0.02 nm, exhibiting excellent catalytic performance and recyclability in the Sonogashira coupling and tandem reaction to synthesize benzofuran derivatives. Further investigation indicates that the modulation of N-heterocyclic carbene sites embedded in the organic cage has an impact on NPs’ catalytic efficiency, thus providing a novel methodology to design superior NP catalysts.
Inspired, but not mimicking: a conversation between artificial intelligence and human intelligence
Authors: Zhao Weijie 
Published: April 2022

Abstract
How intelligent is artificial intelligence (AI)? How intelligent will it become in the future? What is the relationship between AI and human intelligence (HI)? These questions have been a hot topic of discussion in recent years, but no consensus has yet been reached. To discuss these issues, we should first understand the concept of intelligence as well as the underlying mechanisms for both HI and AI. In this NSR Forum, experts from both disciplines gathered to discuss these issues; in particular, the similarities and differences between AI and HI, how these two disciplines could benefit from each other, and the emerging social and ethical challenges of AI.

Xiaolan Fu
Professor at the Institute of Psychology, Chinese Academy of Sciences (CAS)

Yong Gu
Professor at the Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, CAS

Sheng He
Professor at the Institute of Biophysics, CAS

Zhuojun Liu
Professor at the Academy of Mathematics and Systems Science, CAS

Tieniu Tan
Professor at the Institute of Automation, CAS

Zhi-Hua Zhou
Professor at National Key Laboratory for Novel Software Technology, Nanjing University

Huimin Lin (Chair)
Professor at the Institute of Software, CAS
Vaping, Perceptions of Vaping, and Plans to Quit Among E-cigarette Users in the United States and the United Kingdom
Authors: Machado Nathalia Munck , Feldman Keith , Amaral Ligia Menezes do , Ronzani Telmo Mota , Richter Kimber P 
Published: April 2022

Abstract

Introduction
Government and health organizations in the United States and the United Kingdom have taken different stances on e-cigarettes policy. To explore the potential effects of these policies, we describe e-cigarette user characteristics, intentions to quit, and perceived attitudes toward vaping.

Methods
We used the online crowdsourcing platform Prolific to conduct a cross-sectional survey of current vapers in both countries. Measures were drawn from international surveys.

Results
The sample included 1044 vapers (524 United Kingdom; 520 United States) with a mean age of 34. Samples differed by gender (United States: 57% male vs 45% in United Kingdom), race (United States: 79% White vs 90% in United Kingdom) and employment (United States: 73% employed vs 79% in United Kingdom). UK respondents were more likely than US respondents to be ever smokers (89% vs 71%, p &lt; .0001); be daily vapers (69% vs 53%, p &lt; .0001) and to use e-cigarettes to quit smoking (75% vs 65%, p &lt; .0007). Most vapers in the United Kingdom and the United States want to stop vaping (62% vs 61%; p &lt; .9493), but US respondents plan to quit significantly sooner (odds ratio 0.47, p &lt; .0004). Attitudes differed as well. Over half (56%) of UK respondents reported their government-approved e-cigarette use, and 24% felt health care providers had positive views on e-cigarettes versus 29% and 13% from the United States, respectively (p &lt; .0004 for both).

Conclusions
Plans for quitting and perceptions regarding e-cigarettes differ markedly between demographically similar groups of vapers in the two countries. Future research should determine whether e-cigarette cessation for adults should be a public health goal, and if so, identify effective ways to stop.

Implications
The contribution of this study is that it describes differences in behaviors and attitudes of vapers recruited through the same research platform and adjusted to account for minor demographic differences across country samples. For clinicians, these findings suggest that most vapers would welcome assistance in quitting. For researchers and policymakers, findings suggest that government policy regarding nicotine devices might influence behaviors and attitudes related to use and also that future research is needed to determine effective ways to quit.
Pathogen Species Is Associated With Mortality in Nosocomial Bloodstream Infection in Patients With COVID-19
Authors: Gago Juan , Filardo Thomas D , Conderino Sarah , Magaziner Samuel J , Dubrovskaya Yanina , Inglima Kenneth , Iturrate Eduardo , Pironti Alejandro , Schluter Jonas , Cadwell Ken , Hochman Sarah , Li Huilin , Torres Victor J , Thorpe Lorna E , Shopsin Bo 
Published: April 2022

Abstract

Background
The epidemiology of nosocomial bloodstream infections (NBSIs) in patients with coronavirus disease 2019 (COVID-19) is poorly understood, due in part to substantial disease heterogeneity resulting from multiple potential pathogens.

Methods
We identified risk factors for NBSIs and examined the association between NBSIs and mortality in a retrospective cohort of patients hospitalized with COVID-19 in 2 New York City hospitals during the height of the pandemic. We adjusted for the potential effects of factors likely to confound that association, including age, race, illness severity upon admission, and underlying health status.

Results
Between January 1 and October 1, 2020, 1403 patients had a positive blood culture, and 79 and 101 met the stringent criteria for NBSI among non-COVID-19 and COVID-19 patients, respectively. NBSIs occurred almost exclusively among patients who were severely ill with COVID-19 at hospital admission. NBSIs were associated with elevated mortality, even after adjusting for baseline differences in COVID-19 illness (55% cases vs 45% controls; P = .13). Mortality was concentrated in patients with early-onset pneumonia caused by S. aureus and gram-negative bacteria. Less virulent Candida (49%) and Enterococcus (12%) species were the predominant cause of NBSI in the latter stages of hospitalization, after antibiotic treatment and COVID-19 treatments that attenuate immune response. Most Enterococcus and Candida infections did not have an identifiable source and were not associated with common risk factors for infection by these organisms.

Conclusions
Pathogen species and mortality exhibited temporal differences. Early recognition of risk factors among COVID-19 patients could potentially decrease NBSI-associated mortality through early COVID-19 and antimicrobial treatment.