bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detectability of Optical Transients with Timescales of Subseconds
Authors: Arimatsu Ko , Tsumura Kohji , Usui Fumihiko , Ootsubo Takafumi , Watanabe Jun-ichi 
Published: February 2021

Abstract
We search for optical transient sources with durations of ∼0.1 to ∼1.3 s using a data set obtained in the Organized Autotelescopes for Serendipitous Event Survey (OASES) observation campaign. Since the OASES observations were carried out using two independent wide-field and high-cadence observation systems monitored the same field simultaneously, the obtained data set provides a unique opportunity to develop a robust detection method for subsecond optical transients. In the data set of a selected field around the ecliptic and the Galactic plane, we find no astronomical event candidate that satisfies our detection criteria. From the nondetection result, we derive an upper limit on the event rate of subsecond transients around the ecliptic and the Galactic plane for the first time, obtaining ∼0.090 and ∼0.38 hr−1 deg−2 for m = 12 and 13 Vmag, respectively. In addition, future prospects of the subsecond-scale transient event surveys are discussed.
Observational Evidence for Rotational Desorption of Complex Molecules by Radiative Torques from Orion BN/KL
Authors: Tram Le Ngoc , Lee Hyeseung , Hoang Thiem , Michail Joseph M. , Chuss David T. , Nickerson Sarah , Rangwala Naseem , Reach William T. 
Published: February 2021

Abstract
Complex organic molecules (COMs) are believed to form in the ice mantle of dust grains and are released to the gas by thermal sublimation when grain mantles are heated to temperatures of

T

d

≳
100

K

. However, some COMs are detected in regions with temperatures below 100 K. Recently, a new mechanism of rotational desorption due to centrifugal stress induced by radiative torques (RATs) was proposed by Hoang & Tram (2020) that can desorb COMs at low temperatures. In this paper, we report observational evidence for rotational desorption of COMs toward the nearest massive star-forming region, Orion BN/KL. We compare the abundance of three representative COMs that have very high binding energy computed by the rotational desorption mechanism with observations by ALMA, and demonstrate that the rotational desorption mechanism can explain the existence of such COMs. We also analyze the polarization data from SOFIA/HAWC+ and JCMT/SCUBA-2 and find that the polarization degree at far-infrared/submillimeter decreases with increasing the grain temperature for

T

d

≳
71

K

. This is consistent with the theoretical prediction using the RAT alignment theory and Radiative Torque Disruption mechanism. Such an anticorrelation between dust polarization and dust temperature supports the rotational disruption as well as rotational desorption mechanism of COMs induced by RATs.
PSR J0437-4715: The Argentine Institute of Radioastronomy 2019–2020 Observational Campaign
Authors: Sosa Fiscella V. , Palacio S. del , Combi L. , Lousto C. O. , Combi J. A. , Gancio G. , García F. , Gutiérrez E. , Hauscarriaga F. , Kornecki P. , Armengol F. G. López , Mancuso G. C. , Müller A. L. , Bunzel A. Simaz 
Published: February 2021

Abstract
We present the first-year data set of high-cadence, long-duration observations of the bright millisecond pulsar J0437−4715 obtained in the Argentine Institute of Radioastronomy (IAR). Using two single-dish 30 m radio antennas, we gather more than 700 hr of good-quality data with timing precision better than 1 μs. We characterize the white and red timing noise in IAR’s observations, we quantify the effects of scintillation, and we perform single-pulsar searches of continuous gravitational waves, setting constraints in the nHz–μHz frequency range. We demonstrate IAR’s potential for performing pulsar monitoring in the 1.4 GHz radio band for long periods of time with a daily cadence. In particular, we conclude that the ongoing observational campaign of the millisecond pulsar J0437−4715 can contribute to increase the sensitivity of the existing pulsar-timing arrays.
The Kiloparsec-scale Fe Ka Emission in the Compton-thin Seyfert 2 Galaxy NGC 4388 Resolved by Chandra
Authors: Yi Huili , Wang Junfeng , Shu Xinwen , Fabbiano Giuseppina , Pappalardo Cirino , Wang Chen , Yu Hanbo 
Published: February 2021

Abstract
We present imaging and spectral analysis of the combined ∼48 ks Chandra observations of Seyfert 2 galaxy NGC 4388. Compared with previous studies, three prominent extended X-ray structures around the nucleus on a kiloparsec-scale are well imaged, allowing an in-depth spatially resolved study. Both the extended hard continuum (4–6 keV) and the Fe Kα line (6.2–6.7 keV) show similar morphology, consistent with a scenario where the ionizing emission from the nucleus is reprocessed by circumnuclear cold gas, resulting in a weak reflection continuum and an associated neutral Fe Kα line. This has been seen in other Compton-thick active galactic nuclei (AGN), but NGC 4388 is one of the rare cases with a lower column density (N
H < 1.25 × 1024 cm−2) along the line of sight. Significant differences in equivalent width of the Fe Kα emission line (up to a factor of 3) are found for the nuclear and extended regions. Such a difference could be ascribed to different column densities or scattering angles with respect to the line of sight, rather than variations in iron abundances. The northeast and west extended structures appear to be aligned with the larger-scale galactic disk and dust lane in the HST V − H color map, and are located at the peak of molecular gas distribution. The morphology of remaining extended features likely traces edges of a known radio jet, indicating that the outflow at the kiloparsec-scale may have compressed the interstellar gas and produced clumps working as the reflector to enhance line emission. In addition, using [O iv] emission as a proxy of the AGN intrinsic luminosity, we find that both of the extended Fe Kα emission and reflection continuum are linearly correlated with the [O iv] luminosity, which indicates a connection between the central AGN and the extended emission.
Are the Brightest Coronal Loops Always Rooted in Mixed-polarity Magnetic Flux?
Authors: Tiwari Sanjiv K. , Evans Caroline L. , Panesar Navdeep K. , Prasad Avijeet , Moore Ronald L. 
Published: February 2021

Abstract
A recent study demonstrated that freedom of convection and strength of magnetic field in the photospheric feet of active-region (AR) coronal loops, together, can engender or quench heating in them. Other studies stress that magnetic flux cancellation at the loop-feet potentially drives heating in loops. We follow 24 hr movies of a bipolar AR, using extreme ultraviolet images from the Atmospheric Imaging Assembly/Solar Dynamics Observatory (SDO) and line-of-sight (LOS) magnetograms from the Helioseismic and Magnetic Imager (HMI)/SDO, to examine magnetic polarities at the feet of 23 of the brightest coronal loops. We derived Fe xviii emission (hot-94) images (using the Warren et al. method) to select the hottest/brightest loops, and confirm their footpoint locations via non-force-free field extrapolations. From 6″ × 6″ boxes centered at each loop foot in LOS magnetograms we find that ∼40% of the loops have both feet in unipolar flux, and ∼60% of the loops have at least one foot in mixed-polarity flux. The loops with both feet unipolar are ∼15% shorter lived on average than the loops having mixed-polarity foot-point flux, but their peak-intensity averages are equal. The presence of mixed-polarity magnetic flux in at least one foot in the majority of the loops suggests that flux cancellation at the footpoints may drive most of the heating. But the absence of mixed-polarity magnetic flux (to the detection limit of HMI) in ∼40% of the loops suggests that flux cancellation may not be necessary to drive heating in coronal loops—magnetoconvection and field strength at both loop feet possibly drive much of the heating, even in the cases where a loop foot presents mixed-polarity magnetic flux.
ALMA Lensing Cluster Survey: An ALMA Galaxy Signposting a MUSE Galaxy Group at z = 4.3 Behind “El Gordo”
Authors: Caputi K. I. , Caminha G. B. , Fujimoto S. , Kohno K. , Sun F. , Egami E. , Deshmukh S. , Tang F. , Ao Y. , Bradley L. , Coe D. , Espada D. , Grillo C. , Hatsukade B. , Knudsen K. K. , Lee M. M. , Magdis G. E. , Morokuma-Matsui K. , Oesch P. , Ouchi M. , Rosati P. , Umehata H. , Valentino F. , Vanzella E. , Wang W.-H. , Wu J. F. , Zitrin A. 
Published: February 2021

Abstract
We report the discovery of a Multi Unit Spectroscopic Explorer (MUSE) galaxy group at z = 4.32 lensed by the massive galaxy cluster ACT-CL J0102-4915 (aka El Gordo) at z = 0.87, associated with a 1.2 mm source that is at a 2.07 ± 0.88 kpc projected distance from one of the group galaxies. Three images of the whole system appear in the image plane. The 1.2 mm source has been detected within the Atacama Large Millimetre/submillimetre Array (ALMA) Lensing Cluster Survey (ALCS). As this ALMA source is undetected at wavelengths λ < 2 μm, its redshift cannot be independently determined, however, the three lensing components indicate that it belongs to the same galaxy group at z = 4.32. The four members of the MUSE galaxy group have low to intermediate stellar masses (∼107–1010
M
⊙) and star formation rates (SFRs) of 0.4–24 M
⊙ yr−1, resulting in high specific SFRs (sSFRs) for two of them, which suggest that these galaxies are growing fast (with stellar mass doubling times of only ∼2 × 107 yr). This high incidence of starburst galaxies is likely a consequence of interactions within the galaxy group, which is compact and has high velocity dispersion. Based on the magnification-corrected sub-/millimeter continuum flux density and estimated stellar mass, we infer that the ALMA source is classified as an ordinary ultra-luminous infrared galaxy (with associated dust-obscured SFR ∼ 200–300 M
⊙ yr−1) and lies on the star formation main sequence. This reported case of an ALMA/MUSE group association suggests that some presumably isolated ALMA sources are in fact signposts of richer star-forming environments at high redshifts.
Absolute Calibration of Diffuse Radio Surveys at 45 and 150 MHz
Authors: Monsalve Raul A. , Rogers Alan E. E. , Bowman Judd D. , Mahesh Nivedita , Murray Steven G. , Mozdzen Thomas J. , Johnson Leroy , Barrett John , Samson Titu , Lewis David 
Published: February 2021

Abstract
We use measurements from the Experiment to Detect the Global EoR Signature (EDGES) to determine scale and zero-level corrections to the diffuse radio surveys by Guzmán et al. at 45 MHz and by Landecker & Wielebinski at 150 MHz. We find that the map of Guzmán et al. requires a scale correction of 1.076 ± 0.034 (2σ) and a zero-level correction of −160 ± 78 K (2σ) to best-fit the EDGES data. For the map of Landecker & Wielebinski, the scale correction is 1.112 ± 0.023 (2σ) and the zero-level correction is 0.7 ± 6.0 K (2σ). The correction uncertainties are dominated by systematic effects, of which the most significant are uncertainty in the calibration of the EDGES receivers, antenna pointing, and tropospheric and ionospheric effects. We propagate the correction uncertainties to estimate the uncertainties in the corrected maps themselves and find that the 2σ uncertainty in the map brightness temperature is in the range 3.2%–7.5% for the map of Guzmán et al. and 2.1%–9.0% for the map of Landecker & Wielebinski, with the largest percentage uncertainties occurring at high Galactic latitudes. The corrected maps could be used to improve existing diffuse low-frequency radio sky models, which are essential tools in analyses of cosmological 21 cm observations, as well as to investigate the existence of a radio monopole excess above the cosmic microwave background and known Galactic and extragalactic contributions.
Spins of Primordial Black Holes Formed in the Radiation-dominated Phase of the Universe: First-order Effect
Authors: Harada Tomohiro , Yoo Chul-Moon , Kohri Kazunori , Koga Yasutaka , Monobe Takeru 
Published: February 2021

Abstract
The standard deviation of the initial values of the nondimensional Kerr parameter a
* of primordial black holes (PBHs) that formed in the radiation-dominated phase of the universe is estimated to the first order of perturbation for the narrow power spectrum. Evaluating the angular momentum at turnaround based on linearly extrapolated transfer functions and peak theory, we obtain the expression

〈

a

*

2

〉

≃
4.0
×

10

−
3

M

/

M

H

−
1

/

3

1
−

γ

2

1
−
0.072

log

10

(

β

0

(

M

H

)

/

(
1.3
×

10

−
15

)
)

−
1

, where M

H
, β
0(M

H
), and γ are the mass within the Hubble horizon at the horizon entry of the overdense region, the fraction of the universe which collapsed to PBHs at the scale of M

H
, and a quantity that characterizes the width of the power spectrum, respectively. This implies that for M ≃ M

H
, the higher the probability of the PBH formation, the larger the standard deviation of the spins, while PBHs of M ≪ M

H
that formed through near-critical collapse may have larger spins than those of M ≃ M

H
. In comparison to the previous estimate, the new estimate has an explicit dependence on the ratio M/M
H and no direct dependence on the current dark matter density. On the other hand, it suggests that the first-order effect can be numerically comparable to the second-order one.
Role of Polycyclic Aromatic Hydrocarbons on the Cosmic-Ray Ionization Rate in the Galaxy
Authors: Shaw Gargi , Ferland G. J. 
Published: February 2021

Abstract
The cosmic-ray (CR) ionization rate (ζ, s−1) plays an important role in the interstellar medium. It controls ion–molecular chemistry and provides a source of heating. Here we perform a grid of calculations using the spectral synthesis code CLOUDY along nine sightlines toward, HD 169454, HD 110432, HD 204827, λ Cep, X Per, HD 73882, HD 154368, Cyg OB2 5, and Cyg OB2 12. The value of ζ is determined by matching the observed column densities of

H

3

+

and H2. The presence of polycyclic aromatic hydrocarbons (PAHs) affects the free electron density, which changes the

H

3

+

density and the derived ionization rate. PAHs are ubiquitous in the Galaxy, but there are also regions where PAHs do not exist. Hence, we consider clouds within a range of PAH abundances and show their effects on the

H

3

+

abundance. We predict an average CR ionization rate for H2 (ζ(H2)) = (7.88 ± 2.89) × 10−16 s−1 for models with average Galactic PAH abundances, (PAH/H = 10−6.52), except Cyg OB2 5 and Cyg OB2 12. The value of ζ is nearly 1 dex smaller for sightlines toward Cyg OB2 12. We estimate the average value of ζ(H2) = (95.69 ± 46.56) × 10−16 s−1 for models without PAHs.
The Utility of Functional Data Analyses to Reveal Between-Limbs Asymmetries in Those With a History of Anterior Cruciate Ligament Reconstruction
Authors: White McKenzie S. , Horton William Z. , Burland Julie P. , Seeley Matthew K. , Lepley Lindsey K. 
Published: February 2021

Context
Researchers have traditionally used motion capture to quantify discrete data points (peak values) during hop testing. However, these analyses restrict the evaluation to a single time point (ie, certain percentage of stance) and provide only a narrow view of movement. Applying more comprehensive analyses may help investigators identify important characteristics that are masked by discrete analyses often used to screen patients for activity.

Objective
To examine the utility of functional data analyses to reveal asymmetries that are undetectable using discrete (ie, single time point) evaluations in participants with a history of anterior cruciate ligament reconstruction (ACLR) who achieved clinical hop symmetry.

Design
Cross-sectional study.

Setting
Laboratory.

Patients or Other Participants
Fifteen participants with unilateral ACLR (age = 21 ± 3 years, time from surgery = 4 ± 3 years) and 15 control participants without ACLR (age = 23 ± 2 years).

Intervention(s)
Lower extremity biomechanics during the triple–hop-for-distance task for the ACLR and contralateral limbs of patients and a representative limb of control participants were measured.

Main Outcome Measure(s)
Peak sagittal-plane joint power, joint work, and power profiles were determined.

Results
Using discrete analyses, we identified lower peak knee power and work in the ACLR limb compared with the contralateral and control limbs (P &lt; .05) but were unable to demonstrate differences at the ankle or hip. Using functional data analyses, we observed asymmetries at the ankle, knee, and hip between the ACLR and contralateral or control limbs throughout stance (P &lt; .05), and it was revealed that these asymmetries stemmed from knee power deficits that were prominent during early loading.

Conclusions
Despite achieving hop-distance symmetry, the ACLR knees absorbed less power. Although this information was revealed using discrete analyses, underlying asymmetries at the ankle and hip were masked. Using functional data analyses, we found interlimb asymmetries at the ankle, knee, and hip. Importantly, we found that functional data analyses more fully elucidated the extent and source of asymmetries, which can be used by clinicians and researchers alike to aid in clinical decision making.
Time-to-Event Analyses: Return to Unrestricted Participation After Sport-Related Concussion in a Cohort of High School Athletes
Authors: Covassin Tracey , Bretzin Abigail C. , Beidler Erica , Wallace Jessica 
Published: February 2021

Context
Understanding time loss resulting from sport-related concussion (SRC) within individual sports allows high school athletic trainers to provide accurate and evidence-based clinical information. Currently, research regarding patterns of clinical recovery outcomes in high school student-athletes across sports is lacking.

Objective
To describe the time to authorized unrestricted return to participation (RTP) after SRC in a large cohort of high school student-athletes in a variety of sports using a time-to-event analysis.

Design
Descriptive epidemiology study.

Setting
Aggregate injury and player exposure data from the Michigan High School Athletic Association Head Injury Reporting System.

Patients or Other Participants
High school student-athletes.

Main Outcome Measure(s)
Dates for SRC injury events and authorized unrestricted RTP were entered into the Head Injury Reporting System for each case and were used to calculate time to unrestricted RTP. Survival analysis indicated the time to authorized RTP for males and females in weekly increments across sports and academic years. Separate Kaplan-Meier analyses adjusted for SRC cases with a history of concussion also identified the proportions of student-athletes who obtained authorized medical clearance in weekly increments.

Results
A total of 15 821 SRCs, 10 375 (65.6%) in males and 5446 (34.4%) in females, were reported during the 2015–2016 through 2018–2019 academic years. The median time to authorized unrestricted RTP was 11 days for all patients. Approximately 30% of concussed student-athletes were not cleared for unrestricted RTP by 14 days after their SRC diagnosis, with 13% taking longer than 21 days to return to unrestricted RTP after SRC.

Conclusions
The results from this multisite, state-based injury surveillance system indicated that it is not abnormal for high school student-athletes to take longer than 14 days to fully recover from an SRC. This information may be useful for educating high school student-athletes and sport stakeholders, normalizing SRC recovery trajectory perceptions, and establishing realistic RTP timeline expectations.
Effect of immersion in hydrochloric acid and sodium hypochlorite and autoclave sterilization on the force characteristics of orthodontic nickel-titanium open coils
Authors: Noorollahian Saeed , Zakizade Mehrnaz 
Published: February 2021

Background:
Nickel-titanium (NiTi) open coils are common tools in fixed orthodontic treatments to apply light and continuous forces. Their favorable mechanical properties and their relatively high cost have prompted many clinicians to decide to reuse them.

Aim:
The present study aimed to evaluate the effect of 10% hydrochloric acid (HCl) and 5.25% sodium hypochlorite (NaClO) solution and sterilization, on the unloading force of NiTi open-coils.

Materials and Methods:
This experimental in vitro study consisted of 160 NiTi open coils from two brands of Highland Metals and Masel were provided. Each group was randomly divided into four subgroups: control, three rounds of immersion, three rounds of autoclave sterilization, and three rounds of immersion and autoclaving. Each round of immersion process included 1 min in 10% HCl, followed by 5 min in 5.25% NaClO. Spring was compressed for 4 mm. Then, the unloading forces of each spring were recorded at 4, 3, 2, and 1 mm of compression, respectively. The data were analyzed with SPSS (P < 0.05), using one-way ANOVA and independent t-test.

Results:
One-way ANOVA showed a significant difference in the 2-mm compression of Group 1 and 3-mm compressions of Groups 1 and 2 compared to the control group in the Highland metals brand (P < 0.04, P < 0.014, and P < 0.007, respectively). There was no significant difference between the different compressed lengths and groups in the Masel brand.

Conclusion:
One-minute immersion in 10% HCL and 5-min immersion in 5.25% NaOCl, followed by autoclave sterilization, even after repeating the process three times, did not significantly change the force properties of NiTi open springs. Therefore, the re-use of these springs with the above-mentioned method as preparation can be recommended.
Biocompatibility of several colloidal solutions containing nanoparticles on human gingival fibroblasts
Authors: Eslami Neda , Fasihi Fatemeh , Jamalinasab Abdollah , Ahrari Farzaneh 
Published: February 2021

Background:
There is little information concerning the biocompatibility of mouthwashes containing metal nanoparticles. This study was conducted to assess the biocompatibility of colloidal solutions containing zinc oxide (ZnO), copper oxide (CuO), titanium dioxide (TiO2), and silver (Ag) nanoparticles compared with chlorhexidine (CHX) in a culture of human gingival fibroblasts (HGFs).

Materials and Methods:
This was an in vitro, experimental study. Nanoparticles, including ZnO, CuO, TiO2, and Ag, were purchased and added to a water-based solution to produce mouthwashes. The colloidal solutions and CHX were prepared at the minimum inhibitory concentration (MIC) against Streptococcus mutans and Streptococcus sanguis. Cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay on HGFs at the concentrations of MIC, 0.1 MIC, and 0.01 MIC. To determine apoptosis, DNA fragmentation was assessed as “sub-G1” peak on DNA content histogram. The data were analyzed using repeated measures analysis at P < 0.05.

Results:
At all concentrations, the highest and lowest mean of cell viability was related to TiO2 and ZnO groups, respectively. At MIC, the mean cell viability was significantly greater in the TiO2 group than the other groups (except the Ag group) (P < 0.05). At the concentration of 0.01 MIC, the mean cell viability in the colloidal solution containing ZnO nanoparticles was significantly lower than the other solutions (P < 0.05). The CHX and CuO-containing solution displayed the highest rate of apoptosis among the groups.

Conclusion:
The TiO2-containing solution can be suggested as a suitable alternative to CHX to provide antiseptic effects with minimal toxicity.