bluuebunny/crossref_metadata_2025_split huggingface dataset:
Forecast for FAST: from galaxies survey to intensity mapping
Authors: Hu Wenkai , Wang Xin , Wu Fengquan , Wang Yougang , Zhang Pengjie , Chen Xuelei 
Published: March 2020

ABSTRACT
The Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) is the largest single-dish radio telescope in the world. In this paper, we make forecast on the FAST H i large-scale structure survey by mock observations. We consider a drift scan survey with the L-band 19 beam receiver, which may be commensal with the pulsar search and Galactic H i survey. We also consider surveys at lower frequency, using either the current single feed wide-band receiver or a future multibeam phased array feed (PAF) in the UHF band. We estimate the number density of detected H i galaxies and the measurement error in positions and the precision of the surveys are evaluated using both Fisher matrix and simulated observations. The measurement error in the H i galaxy power spectrum is estimated, and we find that the error is relatively large even at moderate redshifts, as the number of positively detected galaxies drops drastically with increasing redshift. However, good cosmological measurement could be obtained with the intensity mapping technique where the large scale H i distribution is measured without resolving individual galaxies. The figure of merit for the dark energy equation of state with different observation times is estimated, and we find that with the existing L-band multibeam receiver, a good measurement of low redshift large-scale structure can be obtained, which complements the existing optical surveys. With a PAF in the UHF band, the constraint can be much stronger, reaching the level of a dark energy task force stage IV experiment.
Non-local thermodynamic equilibrium line formation for Si i–ii–iii in A–B stars and the origin of Si ii emission lines in ι Her
Authors: Mashonkina Lyudmila 
Published: March 2020

ABSTRACT
A comprehensive model atom was developed for Si i–ii–iii using the most up-to-date atomic data available so far. Based on non-local thermodynamic equilibrium (NLTE) line formation for Si i, Si ii and Si iii and high-resolution observed spectra, we determined the NLTE abundances for a sample of nine unevolved A9–B3 type stars with well-determined atmospheric parameters. For each star, NLTE reduces the line-to-line scatter for Si ii substantially compared with the LTE case and leads to consistent mean abundances from lines of different ionization stages. In the hottest star of our sample, ι Her, Si ii is subject to overionization that drives emission in the lines arising from the high-excitation doublet levels. Our NLTE calculations reproduced 10 emission lines of Si ii observed in ι Her. The same overionization effect leads to greatly weakened Si ii lines, which are observed in absorption in ι Her. Large positive NLTE abundance corrections (up to 0.98 dex for 5055 Å) were useful for achieving consistent mean abundances from lines of the two ionization stages, Si ii and Si iii. It was found that NLTE effects are overestimated for the Si ii 6347, 6371 Å doublet in ι Her, while the new model atom works well for cooler stars. At this stage, we failed to understand this problem. We computed a grid of the NLTE abundance corrections for lines of Si i, Si ii and Si iii in model atmospheres with effective temperatures and surface gravities characteristic of unevolved A–B type stars.
A compact X-ray emitting binary in likely association with 4FGL J0935.3+0901
Authors: Wang Zhongxiang , Xing Yi , Zhang Jujia , Boutsia Konstantina , Wang Gege , V Jithesh , Burdge Kevin B , Coughlin Michael W , Duev Dmitry A , Kulkarni S R , Riddle Reed , Serabyn Eugene 
Published: March 2020

ABSTRACT
4FGL J0935.3+0901 is a γ-ray source detected by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope. We have conducted detailed analysis of the LAT data for this source and multiwavelength studies of the source field. Its γ-ray emission can be described with a power law (Γ = 2.0 ± 0.2) with an exponential cut-off (Ec = 2.9 ± 1.6 GeV), while the flux shows significant long-term variations. From analysis of archival Neil Gehrels Swift Observatory X-Ray Telescope data, we find only one X-ray source in the LAT’s 2σ error region. Within a $3.7\,{\rm arcsec}$ radius error circle of the X-ray source, there is only one optical object down to r′ ∼ 23 mag. Time-resolved photometry of the optical object indicates a likely 2.5 h periodic modulation, while its spectrum shows double-peaked hydrogen and helium emission lines (similar to those seen in accretion discs in low-mass X-ray binaries). Combining these results, we conclude that we have discovered a compact X-ray emitting binary in likely association with 4FGL J0935.3+0901, i.e. a millisecond pulsar (MSP) binary. We discuss the implication of the optical spectral features: this binary could be a transitional MSP system at a subluminous disc state, although the other possibility, the binary in a rotation-powered state showing the optical emission lines due to intrabinary interaction processes, cannot be excluded. Further observational studies will help to determine detailed properties of this candidate MSP binary and thus clarify its current state.
How do bound star clusters form?
Authors: Krumholz Mark R , McKee Christopher F 
Published: March 2020

ABSTRACT
Gravitationally bound clusters that survive gas removal represent an unusual mode of star formation in the Milky Way and similar spiral galaxies. While forming, they can be distinguished observationally from unbound star formation by their high densities, virialized velocity structures, and star formation histories that accelerate towards the present, but extend multiple free-fall times into the past. In this paper, we examine several proposed scenarios for how such structures might form and evolve, and carry out a Bayesian analysis to test these models against observed distributions of protostellar age, counts of young stellar objects relative to gas, and the overall star formation rate of the Milky Way. We show that models in which the acceleration of star formation is due either to a large-scale collapse or a time-dependent increase in star formation efficiency are unable to satisfy the combined set of observational constraints. In contrast, models in which clusters form in a ‘conveyor belt’ mode where gas accretion and star formation occur simultaneously, but the star formation rate per free-fall time is low, can match the observations.
TESS observations of pulsating subdwarf B stars: extraordinarily short-period gravity modes in CD−28° 1974
Authors: Reed M D , Shoaf K A , Németh P , Vos J , Uzundag M , Baran A S , Sahoo S K , Jeffery C S , Telting J H , Østensen R H 
Published: March 2020

ABSTRACT
Transiting Exoplanet Survey Satellite (TESS) observations show CD−28° 1974 to be a gravity(g)-mode-dominated hybrid pulsating subdwarf B (sdBV) star. It shows 13 secure periods that form an ℓ = 1 asymptotic sequence near the typical period spacing. Extraordinarily, these periods lie between 1500 and 3300 s, whereas typical $\ell = 1\, g$ modes in sdBV stars occur between 3300 and 10 000 s. This indicates a structure somewhat different from typical sdBV stars. CD−28° 1974 has a visually close F/G main-sequence companion 1.33 arcsec away, which may be a physical companion. Gaia proper motions indicate a comoving pair with the same distance. A reanalysis of Ultraviolet and Visual Echelle Spectrograph (UVES) spectra failed to detect any orbital motion and the light curve shows no reflection effect or ellipsoidal variability, making an unseen close companion unlikely. The implication is that CD−28° 1974 has become a hot subdwarf via single star or post-merger evolution.
The radio pulsar population of the Small Magellanic Cloud
Authors: Titus N , Toonen S , McBride V A , Stappers B W , Buckley D A H , Levin L 
Published: March 2020

ABSTRACT
We model the present-day, observable, normal radio pulsar population of the Small Magellanic Cloud (SMC). The pulsars are generated with SeBa, a binary population synthesis code that evolves binaries and the constituent stellar objects up to remnant formation and beyond. We define radio pulsars by selecting neutron stars (NSs) that satisfy a selection of criteria defined by Galactic pulsars, and apply the detection thresholds of previous and future SMC pulsar surveys. The number of synthesized and recovered pulsars is exceptionally sensitive to the assumed star formation history and applied radio luminosity model, but is not affected extensively by the assumed common-envelope model, metallicity, and NS kick velocity distribution. We estimate that the SMC formed (1.6 ± 0.3) ×104 normal pulsars during the last 100 Myr. We study which pulsars could have been observed by the Parkes multibeam survey of the SMC, by applying the survey’s specific selection effects, and recover 4.0 ± 0.8 synthetic pulsars. This is in agreement with their five observed pulsars. We also apply a proposed MeerKAT configuration for the upcoming SMC survey, and predict that the MeerKAT survey will detect 17.2 ± 2.5 pulsars.
On the spatial and temporal non-locality of dynamo mean-field effects in supersonic interstellar turbulence
Authors: Gressel Oliver , Elstner Detlef 
Published: March 2020

ABSTRACTThe interstellar medium (ISM) of the Milky Way and nearby disc galaxies harbour large-scale coherent magnetic fields of microgauss strength, that can be explained via the action of a mean-field dynamo. As in our previous work, we aim to quantify dynamo effects that are self-consistently emerging in realistic direct magnetohydrodynamic simulations, but we generalize our approach to the case of a non-local (non-instantaneous) closure relation, described by a convolution integral in space (time). To this end, we leverage our comprehensive simulation framework for the supernova-regulated turbulent multiphase ISM. By introducing spatially (temporally) modulated mean fields, we extend the previously used test-field method to the spectral realm – providing the Fourier representation of the convolution kernels. The resulting spectra of the dynamo mean-field coefficients that we obtain broadly match expectations and allow to rigorously constrain the degree of scale separation in the Galactic dynamo. A surprising result is found for the diamagnetic pumping term, which increases in amplitude when going to smaller scales. Our results amount to the most comprehensive description of dynamo mean-field effects in the Galactic context to date. Surveying the relevant parameter space and quenching behaviour, this will ultimately enable the development of assumption-free subgrid prescriptions for otherwise unresolved global galaxy simulations.
Pulsation among TESS A and B stars and the Maia variables
Authors: Balona L A , Ozuyar D 
Published: March 2020

ABSTRACT
Classification of over 50 000 TESS stars in sectors 1–18 has resulted in the detection of 766 pulsating main-sequence B stars as well as over 5000 δ Scuti, 2300 γ Doradus, and 114 roAp candidates. Whereas it has been assumed that high-frequency pulsations among B-type main-sequence stars are confined to the early B-type β Cephei stars, the observations indicate that high frequencies are to be found over the whole B-star range, eventually merging with δ Scuti stars. The cool B stars pulsating in high frequencies are called Maia variables. It is shown that Maia variables are not rapidly rotating and thus cannot be β Cephei pulsators that appear to have lower temperatures due to gravity darkening. In the region where β Cephei variables are found, the proportion of pulsating stars is larger and amplitudes are higher and a considerable fraction pulsate in a single mode and low rotation rate. There is no distinct region of slowly pulsating B stars (SPB stars). Stars pulsating solely in low frequencies are found among all B stars. At most, only one-third of B stars appear to pulsate. These results, as well as the fact that a large fraction of A and B stars show rotational modulation, indicate a need for a revision of current ideas regarding stars with radiative envelopes.
A transient α-helix in the N-terminal RNA recognition motif of polypyrimidine tract binding protein senses RNA secondary structure
Authors: Maris Christophe , Jayne Sandrine , Damberger Fred F , Beusch Irene , Dorn Georg , Ravindranathan Sapna , Allain Frédéric H-T 
Published: March 2020

Abstract
The polypyrimidine tract binding protein (PTB) is a multi-domain protein involved in alternative splicing, mRNA localization, stabilization, polyadenylation and translation initiation from internal ribosome entry sites (IRES). In this latter process, PTB promotes viral translation by interacting extensively with complex structured regions in the 5′-untranslated regions of viral RNAs at pyrimidine-rich targets located in single strand and hairpin regions. To better understand how PTB recognizes structured elements in RNA targets, we solved the solution structure of the N-terminal RNA recognition motif (RRM) in complex with an RNA hairpin embedding the loop sequence UCUUU, which is frequently found in IRESs of the picornovirus family. Surprisingly, a new three-turn α3 helix C-terminal to the RRM, folds upon binding the RNA hairpin. Although α3 does not mediate any contacts to the RNA, it acts as a sensor of RNA secondary structure, suggesting a role for RRM1 in detecting pyrimidine tracts in the context of structured RNA. Moreover, the degree of helix formation depends on the RNA loop sequence. Finally, we show that the α3 helix region, which is highly conserved in vertebrates, is crucial for PTB function in enhancing Encephalomyocarditis virus IRES activity.
A Comparison of Minimally Invasive and Open Transforaminal Lumbar Interbody Fusion for Grade 1 Degenerative Lumbar Spondylolisthesis: An Analysis of the Prospective Quality Outcomes Database
Authors: Chan Andrew K , Bisson Erica F , Bydon Mohamad , Foley Kevin T , Glassman Steven D , Shaffrey Christopher I , Wang Michael Y , Park Paul , Potts Eric A , Shaffrey Mark E , Coric Domagoj , Knightly John J , Fu Kai-Ming , Slotkin Jonathan R , Asher Anthony L , Virk Michael S , Kerezoudis Panagiotis , Alvi Mohammed A , Guan Jian , Haid Regis W , Mummaneni Praveen V 
Published: March 2020

ABSTRACT

BACKGROUND
It remains unclear if minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is comparable to traditional, open TLIF because of the limitations of the prior small-sample-size, single-center studies reporting comparative effectiveness.

OBJECTIVE
To compare MI-TLIF to traditional, open TLIF for grade 1 degenerative lumbar spondylolisthesis in the largest study to date by sample size.

METHODS
We utilized the prospective Quality Outcomes Database registry and queried patients with grade 1 degenerative lumbar spondylolisthesis who underwent single-segment surgery with MI- or open TLIF methods. Outcomes were compared 24 mo postoperatively.

RESULTS
A total of 297 patients were included: 72 (24.2%) MI-TLIF and 225 (75.8%) open TLIF. MI-TLIF surgeries had lower mean body mass indexes (29.5 ± 5.1 vs 31.3 ± 7.0, P = .0497) and more worker's compensation cases (11.1% vs 1.3%, P < .001) but were otherwise similar. MI-TLIF had less blood loss (108.8 ± 85.6 vs 299.6 ± 242.2 mL, P < .001), longer operations (228.2 ± 111.5 vs 189.6 ± 66.5 min, P < .001), and a higher return-to-work (RTW) rate (100% vs 80%, P = .02). Both cohorts improved significantly from baseline for 24-mo Oswestry Disability Index (ODI), Numeric Rating Scale back pain (NRS-BP), NRS leg pain (NRS-LP), and Euro-Qol-5 dimension (EQ-5D) (P > .001). In multivariable adjusted analyses, MI-TLIF was associated with lower ODI (β = −4.7; 95% CI = −9.3 to −0.04; P = .048), higher EQ-5D (β = 0.06; 95% CI = 0.01-0.11; P = .02), and higher satisfaction (odds ratio for North American Spine Society [NASS] 1/2 = 3.9; 95% CI = 1.4-14.3; P = .02). Though trends favoring MI-TLIF were evident for NRS-BP (P = .06), NRS-LP (P = .07), and reoperation rate (P = .13), these results did not reach statistical significance.

CONCLUSION
For single-level grade 1 degenerative lumbar spondylolisthesis, MI-TLIF was associated with less disability, higher quality of life, and higher patient satisfaction compared with traditional, open TLIF. MI-TLIF was associated with higher rates of RTW, less blood loss, but longer operative times. Though we utilized multivariable adjusted analyses, these findings may be susceptible to selection bias.
Is Buprenorphine Effective for Chronic Pain? A Systematic Review and Meta-analysis
Authors: Lazaridou Asimina , Paschali Myrella , Edwards Robert R , Gilligan Christopher 
Published: March 2020

Abstract

Objective
The objective was to perform a systematic review and meta-analysis of the literature on the effects of buprenorphine on chronic pain outcomes (i.e., patient-reported pain intensity) in patients with and without opioid use disorder (OUD).

Design
Ovid/Medline, PubMed, Embase, and the Cochrane Library were searched for studies that explored the effectiveness (in reducing pain) of buprenorphine treatment for chronic pain patients with and without a history of OUD. Randomized controlled trials and observational studies were included in the review.

Methods
Two separate searches were conducted to identify buprenorphine trials that included chronic pain patients either with or without OUD. Five studies used validated pain report measures and included a chronic pain population with OUD. Nine studies used validated report measures and included chronic pain patients without OUD. Meta-analysis was performed using the R, version 3.2.2, Metafor package, version 1.9–7.

Results
The meta-analysis revealed that buprenorphine has a beneficial effect on pain intensity overall, with a small mean effect size in patients with comorbid chronic pain and OUD and a moderate- to large-sized effect in chronic pain patients without OUD.

Conclusions
Our results indicate that buprenorphine is modestly beneficial in reducing pain intensity in patients without OUD. Although informative, these findings should be carefully interpreted due to the small amount of data available and the variation in study designs.
The Conceptual–Contextual Gap between Non-recurrence and Transformative Police Reform in Post-Conflict States
Authors: McAuliffe Pádraig 
Published: March 2020

Abstract
The idea of a systemic and holistic approach to police reform that addresses larger structural issues, such as poverty or discrimination against marginalized groups, is an attractive one. It is understandable that reformers and critics aspire to develop police forces that are so well-trained, transparent, and open to external oversight that responsiveness to community needs broadly understood becomes second nature. However, it is not enough to identify the needs of the most marginalized—policy-makers must identify where and how aspirations for change fit the domestic political economy in the security sector. This article has outlined a conceptual–contextual gap in policebuilding, pin-pointing three other main barriers to transformation (i) the necessary preoccupation with and diversion of resources to technical reform, (ii) the need to deal with immediate post-conflict security needs, and (iii) a political economy that does not support the type of responsive, socially democratic culture where transformative policebuilding becomes feasible.
All the News That’s Fit to Ignore
Authors: Toff Benjamin , Kalogeropoulos Antonis 
Published: March 2020

Abstract
In a fragmented digital media environment where news is increasingly encountered passively in social media feeds and via automated mobile alerts, active avoidance of news, rather than deliberate consumption, takes on outsized importance in shaping what it means to be an informed citizen. This article systematically evaluates the factors that predict news avoidance behaviors, considering both individual- and country-level explanations. Using a large-scale quantitative, comparative approach, we examine more than 67,000 survey respondents across 35 countries worldwide and find consistent evidence for how factors including demographics, political attitudes, and news genre preferences shape avoidance consistently across information environments. But we also show how country-level contextual factors, what we call “cultures of news consumption,” influence behaviors beyond that which is explained by respondent-level differences. Specifically, levels of press freedom and political freedom and stability are shown to negatively predict rates of news avoidance. These findings suggest that many people’s news use practices depend not only on personal characteristics and preferences but quite sensibly on the news available to them, which they may have good reason to view as deficient or untrustworthy, as well as culturally specific norms around its value and utility.
The Cross-Section of Risk and Returns
Authors: Daniel Kent , Mota Lira , Rottke Simon , Santos Tano 
Published: March 2020

Abstract
A common practice in the finance literature is to create characteristic portfolios by sorting on characteristics associated with average returns. We show that the resultant portfolios are likely to capture not only the priced risk associated with the characteristic but also unpriced risk. We develop a procedure to remove this unpriced risk using covariance information estimated from past returns. We apply our methodology to the five Fama-French characteristic portfolios. The squared Sharpe ratio of the optimal combination of the resultant characteristic-efficient portfolios is 2.13, compared with 1.17 for the original characteristic portfolios.
Older age onset of systemic sclerosis – accelerated disease progression in all disease subsets
Authors: Moinzadeh Pia , Kuhr Kathrin , Siegert Elise , Mueller-Ladner Ulf , Riemekasten Gabriela , Günther Claudia , Kötter Ina , Henes Jörg , Blank Norbert , Zeidler Gabriele , Pfeiffer Christiane , Juche Aaron , Jandova Ilona , Ehrchen Jan , Schmalzing Marc , Susok Laura , Schmeiser Tim , Sunderkoetter Cord , Distler Jörg H W , Worm Margitta , Kreuter Alexander , Krieg Thomas , Hunzelmann Nicolas ,   and Registry of the German Network for Systemic Scleroderma
Published: March 2020

AbstractObjectivesSystemic sclerosis is a heterogeneous, multisystem disease. It can occur at any age, but most patients develop the disease between the age of 40 to 50 years. There is controversial evidence on whether/how the age at disease onset affects their clinical phenotype. We here investigate the relationship between age at disease onset and symptoms in a large cohort of SSc patients (lcSSc, dcSSc and SSc-overlap syndromes).MethodsClinical data of the registry of the German Network for Systemic Scleroderma including 3281 patients were evaluated and subdivided into three age groups at disease onset (&lt;40 years, 40–60 years, &gt;60 years).ResultsAmong all SSc patients, 24.5% developed their first non-Raynaud phenomenon symptoms at the age &lt;40 years, and 22.5% were older than 60 years of age. In particular, older patients at onset developed the lcSSc subset significantly more often. Furthermore, they had pulmonary hypertension more often, but digital ulcerations less often. Remarkably, the course of the disease was more rapidly progressing in the older cohort (&gt;60 years), except for gastrointestinal and musculoskeletal involvement. No significant difference was found for the use of corticosteroids. However, significantly, fewer patients older than 60 years received immunosuppressive treatment.ConclusionIn this large registry, ∼25% of patients developed SSc at an age above 60 years with an increased frequency of lcSSc. In this age group, an onset of internal organ involvement was significantly accelerated across all three subsets. These findings suggest that, in the elderly cohort, more frequent follow-up examinations are required for an earlier detection of organ complications.