bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gaia Early Data Release 3
Authors: Rowell N. , Davidson M. , Lindegren L. , van Leeuwen F. , Castañeda J. , Fabricius C. , Bastian U. , Hambly N. C. , Hernández J. , Bombrun A. , Evans D. W. , De Angeli F. , Riello M. , Busonero D. , Crowley C. , Mora A. , Lammers U. , Gracia G. , Portell J. , Biermann M. , Brown A. G. A. 
Published: December 2020

Context. The unprecedented astrometric precision of the Gaia mission relies on accurate estimates of the locations of sources in the Gaia data stream. This is ultimately performed by point spread function (PSF) fitting, which in turn requires an accurate reconstruction of the PSF, including calibrations of all the major dependences. These include a strong colour dependence due to Gaia’s broad G band and a strong time dependence due to the evolving contamination levels and instrument focus. Accurate PSF reconstruction is also important for photometry. Gaia Early Data Release 3 (EDR3) will, for the first time, use a PSF calibration that models several of the strongest dependences, leading to signficantly reduced systematic errors.
Aims. We describe the PSF model and calibration pipeline implemented for Gaia EDR3, including an analysis of the calibration results over the 34 months of data. We include a discussion of the limitations of the current pipeline and directions for future releases. This will be of use both to users of Gaia data and as a reference for other precision astrometry missions.
Methods. We develop models of the 1D line spread function (LSF) and 2D PSF profiles based on a linear combination of basis components. These are designed for flexibility and performance, as well as to meet several mathematical criteria such as normalisation. We fit the models to selected primary sources in independent time ranges, using simple parameterisations for the colour and other dependences. Variation in time is smoothed by merging the independent calibrations in a square root information filter, with resets at certain mission events that induce a discontinuous change in the PSF.
Results. The PSF calibration shows strong time and colour dependences that accurately reproduce the varying state of the Gaia astrometric instrument. Analysis of the residuals reveals both the performance and the limitations of the current models and calibration pipeline, and indicates the directions for future development.
Conclusions. The PSF modelling and calibration carried out for Gaia EDR3 represents a major step forwards in the data processing and will lead to reduced systematic errors in the core mission data products. Further significant improvements are expected in the future data releases.
Coronal mass ejections observed by heliospheric imagers at 0.2 and 1 au
Authors: Braga Carlos R. , Vourlidas Angelos 
Published: December 2020

Context. We study two coronal mass ejections (CMEs) observed between April 1 to 2, 2019 by both the inner Wide-Field Imager for Parker Solar Probe (WISPR-I) onboard the Parker Solar Probe (PSP) spacecraft (located between about 46 and 38 solar radii during this period) and the inner heliospheric imager (HI-1) onboard the Solar Terrestrial Relations Observatory Ahead (STEREO-A) spacecraft, orbiting the Sun at about 0.96 au. This is the first study of CME observations from two viewpoints in similar directions but at considerably different solar distances.
Aims. Our objective is to derive CME kinematics from WISPR-I observations and to compare them with results from HI-1. This allows us to understand how the PSP observations affect the CME kinematics, especially due to its proximity to the Sun.
Methods. We estimated the CME positions, speeds, accelerations, propagation directions, and longitudinal deflections using imaging observations from two spacecrafts and a set of analytical expressions that consider the CME as a point structure and take the rapid change in spacecraft position into account. We derived the kinematics using each viewpoint independently and both viewpoints as a constraint.
Results. We found that both CMEs are slow (<400 km s−1), propagating eastward of the Sun-Earth line (westward of PSP and STEREO-A). The second CME seems to accelerate between ~0.1 and ~0.2 au and deflect westward with an angular speed consistent with the solar rotation speed. We found some discrepancies in the CME solar distance (up to 0.05 au, particularly for CME #1), latitude (up to ~10°), and longitude (up to 24°) when comparing results from different fit cases (different observations or set of free parameters).
Conclusions. Discrepancies in longitude are likely due to the feature that is tracked visually, rather than instrumental biases or fit assumptions. For similar reasons, the CME #1 solar distance, as derived from WISPR-I observations, is larger than the HI-1 result, regardless of the fit parameters considered. Error estimates for CME kinematics do not show any clear trend associated with the observing instrument. The source region location and the lack of any clear in situ counterparts (both at near-Earth and at PSP) support our estimate of the propagation direction for both events.
Magnetoresistance investigation in the mixed state of a high temperature superconductor
Authors: Bghour Mustapha , Labrag Abdelaziz , El Hamidi Habiba , Abou El Hassan Ahmed , Taoufik Ahmed 
Published: December 2020

In this work, we analyze the behavior of the magnetoresistance R (H, T) of a high temperature superconductor YBa
2
Cu
3
O
7−δ
thin film optimally doped. Measurements of the magnetoresistance were carried out in the mixed state for a magnetic field up to 14 T applied parallel to c − axis then parallel to ab − plane with a dc transport current of 100 and 500 nA, 0.1 and 0.3 mA perpendicular to the magnetic field direction in both cases. The obtained results show that the magnetoresistance is in a good agreement with the thermally assisted flux creep. However, the magnetoresistance in the flux flow regime cannot be described by the Barden-Stephen model which conjectures another origin of these results. In this sense, the quantum fluctuations of the order parameter is a good alternative to understanding the shape of the magnetoresistance. The comparison of the magnetoresistance of the two directions shows that [see formula in PDF] is larger than [see formula in PDF] with anisotropy factor [see formula in PDF] depending on temperature and magnetic field. The irreversibility line H

irr
(T) as well as H

C2 (T) are determined and the first one is fitted with the phenomenological model H

irr
(T) = H

irr
(0) (1 − T/T

o
)
α
where H

irr
(0), T

o
and α are parameters obtained from the fit. The investigation of the scaling law allows us to prove that a crossover from 3D to 2D behavior is a feature of our sample which justifies the existence of the decoherence effect.
Risk of colonoscopy-related complications in a fecal immunochemical test-based population colorectal cancer screening program
Authors: Hsu Wen-Feng , Chang Chi-Yang , Chang Chun-Chao , Chang Li-Chun , Chen Chien-Hua , Lin Chun-Che , Lin Yu-Min , Lee Chia-Long , Wu Hong-Yuan , Lee Hsin-Chung , Lee Yi-Chia , Su Ming-Yao , Lin Li-Ju , Chia Shu-Li , Wu Ming-Shiang , Chiu Han-Mo ,   for the Colonoscopy Quality Assurance Joint Working Group of Taiwan Colorectal Cancer Screening Program and Digestive Endoscopy Society of Taiwan
Published: December 2020

Abstract
Background The likelihood of advanced or synchronous neoplasms is significantly higher in fecal immunochemical test (FIT)-positive individuals than in the general population. The magnitude of the colonoscopy-related complication rate in FIT-positive individuals remains unknown. This study aimed to elucidate the colonoscopy-related complication rate after a positive FIT result and compare it with the rate when colonoscopy was performed for other purposes.
Methods Information regarding colonoscopy-related severe complications after a positive FIT result (FIT-colonoscopy) and ordinary colonoscopy during 2010–2014 was collected from the Taiwanese Colorectal Cancer Screening Program Database and National Health Insurance Research Database. Severe complications included significant bleeding, perforation, and cardiopulmonary events ≤ 14 days after colonoscopy. The number of events per 1000 procedures was used to quantify complication rates. Multivariate analysis was conducted to assess the association of various factors with severe complications associated with FIT-colonoscopy compared with ordinary colonoscopy.
Results 319 114 FIT-colonoscopies (214 955 patients) were identified, 51 242 (16.1 %) of which included biopsy and 94 172 (29.5 %) included polypectomy. Overall, 2125 significant bleedings (6.7 ‰) and 277 perforations (0.9 ‰) occurred ≤ 14 days after FIT-colonoscopy. Polypectomy, antiplatelet use, and anticoagulant use were associated with higher risk of complications (adjusted odds ratio [aOR] 4.41, 95 % confidence interval [CI] 4.05–4.81); aOR 1.35, 95 %CI 1.12–1.53; aOR 1.88, 95 %CI 0.61–5.84, respectively). Compared with ordinary colonoscopy, FIT-colonoscopy involved significantly higher risk of significant bleeding (aOR 3.10, 95 %CI 2.90–3.32).
Conclusions FIT-colonoscopy was associated with a more than two-fold risk of significant bleeding, especially when polypectomy was performed.
Image of the Month: Decision-Making in Surgery for Late Onset Hirschsprung Disease
Authors: Apte Anisha , McKenna Elise , Levitt Marc A. 
Published: December 2020

AbstractWe present a case of a 14-year-old boy with chronic distension, poor growth, and chronic constipation. He undergoes anorectal manometry and rectal biopsy, confirming the diagnosis of Hirschsprung disease (HD). The case is presented with a key image and associated questions to prompt discussion on strategies for management and treatment of HD in late-diagnosed children.
Neonatal Survivability following Previable PPROM after Hospital Readmission for Intervention
Authors: LeMoine Felicia , Moore Robert C. , Chapple Andrew , Moore Ferney A. , Sutton Elizabeth 
Published: December 2020

AbstractObjective To describe our hospital's experience following expectant management of previable preterm prelabor rupture of membranes (pPPROM).Study Design Retrospective review of neonatal survival and maternal and neonatal outcomes of pPPROM cases between 2012 and 2019 at a tertiary referral center in South Central Louisiana. Regression analyses were performed to identify predictors of neonatal survival.Results Of 81 cases of pPPROM prior to 23 weeks gestational age (WGA), 23 survived to neonatal intensive care unit discharge (28.3%) with gestational age at rupture ranging from 180/7 to 226/7 WGA. Increased latency (adjusted odds ratio [aOR] = 1.30, 95% confidence interval [CI] = 1.11, 1.52) and increased gestational age at rupture (aOR = 1.62, 95% CI = 1.19, 2.21) increased the probability of neonatal survival. Antibiotics prior to delivery were associated with increased latency duration (adjusted hazard ratio = 0.55, 95% CI = 0.42, 0.74).Conclusion Neonatal survival rate following pPPROM was 28.3%. Later gestational age at membrane rupture and increased latency periods are associated with increased neonatal survivability. Antibiotic administration following pPPROM increased latency duration.
COVID-19 lockdown induces disease-mitigating structural changes in mobility networks
Authors: Schlosser Frank , Maier Benjamin F. , Jack Olivia , Hinrichs David , Zachariae Adrian , Brockmann Dirk 
Published: December 2020

Significance
During the COVID-19 pandemic, mobility restrictions have proved to be an effective mitigation strategy in many countries. To apply these measures more efficiently in the future, it is important to understand their effects in detail. In this study, we use mobile phone data to uncover profound structural changes in mobility in Germany during the pandemic. We find that a strong reduction of long-distance travel rendered mobility to be more local, such that distant parts of the country became less connected. We demonstrate that due to this loss of connectivity, infectious diseases can be slowed down in their spatial spread. Our study provides important insights into the complex effects of mobility restrictions for policymakers and future research.
Face masks considerably reduce COVID-19 cases in Germany
Authors: Mitze Timo , Kosfeld Reinhold , Rode Johannes , Wälde Klaus 
Published: December 2020

Significance
Mitigating the spread of COVID-19 is the objective of most governments. It is of utmost importance to understand how effective various public health measures are. We study the effectiveness of face masks. We employ public regional data about reported severe acute respiratory syndrome coronavirus 2 infections for Germany. As face masks became mandatory at different points in time across German regions, we can compare the rise in infections in regions with masks and regions without masks. Weighing various estimates, we conclude that 20 d after becoming mandatory face masks have reduced the number of new infections by around 45%. As economic costs are close to zero compared to other public health measures, masks seem to be a cost-effective means to combat COVID-19.
Defining linguistic reasoning
Authors: Dielemans Roy , Coppen Peter-Arno 
Published: December 2020

Abstract
Until recently, throughout the world, linguistic theory was virtually absent in secondary education, mostly limited to
grammar teaching still based on 19th century linguistic theory. There is a growing call, however, for enriching grammar teaching with modern
linguistic insights, integrating higher order critical thinking skills, like reasoning. This study tries to lay the groundwork for a model
of linguistic reasoning in particular.
Based on a well-established model for historical reasoning (Van Boxtel & Van Drie,
2018), a linguistic model is developed in two steps. First, the components of the historical model are theoretically analysed and
transposed to the linguistic domain, and second, the model is applied in qualitative analysis of linguistic experts’ reasoning.
It is found that the model fits linguistic reasoning fairy well: all central components can be observed, and are evenly
distributed over different experts. It is concluded that the linguistic reasoning model can be used in the development of a new grammar
pedagogy.
ASI Space Science Data Center participation to high-school outreach program
Authors: Zinzi Angelo , Pittori Carlotta , Tagliamonte Rosa , Nichelli Elisa 
Published: December 2020

Abstract
Since 2017 the Italian Space Agency (ASI) participates to so-called ‘Alternanza Scuola-Lavoro’ (i.e. ‘school-work synergy’) outreach projects promoted by the Italian government, and the ASI Space Science Data Center (SSDC) actively contributes to them, with the primary aim of bringing students closer to space-related activities before choosing their university studies.
The SSDC outreach programme is split into two parts: one theoretical, in which relevant topic are presented and explained, and one practical, consisting of hands-on activities aimed to replicate scientific analysis of real space data. The impact of the programme on students’ attitude is then evaluated by means of questionnaires specifically designed to gather information on the students’ educational background, the level of engagement triggered by the proposed activities, their relevance to school-based activities, and the perceived ease of understanding of the covered topics.
As reported in this paper, the analysis of the answers clearly shows that students greatly appreciated this outreach project, supporting its possible expansion and development, even articulated in a more complex pedagogical plan, as already done for one school in a pilot case. Therefore, we plan to expand these activities in the next future both by including new topics (e.g. cosmology, stellar physics), and by proposing new more articulated teaching pathways inclusive of on-site activities in the classroom.
Studies on the near-surface trapping of deuterium in implantation experiments
Authors: Maya P.N. , Mukherjee S. , Sharma P. , Karki V. , Singh M. , Satyaprasad A. , Kumar R. , Vala S. , Abhangi M. , Kannan S. , Pujari P.K. , Raole P.M. , Deshpande S.P. 
Published: December 2020

Abstract
Surface-shifted deuterium profiles are re-examined in deuterium-ion irradiation experiments by using a combined experimental and modelling approach. Recrystallized tungsten foil samples were irradiated with energetic deuterium ions and the defect and deuterium depth profiles were studied using positron annihilation spectroscopy and secondary ion mass spectroscopy. We report direct experimental evidence of trapping of deuterium at the vacancies created by the deuterium ions themselves during the implantation by using positron annihilation studies. The deuterium profile is simulated using a Monte-Carlo diffusion model by taking into account the defect-aided diffusion of deuterium due to the local strain field created by the vacancies. The simulations also elucidate the role of the anisotropy in the diffusion and trapping of deuterium in ion-implantation experiments in metals.
Effect of the channel divergence ratio on heat transfer in a turbulent flow around the rib-step system
Authors: Barsukov A V , Terekhov V V , Terekhov V I 
Published: December 2020

Abstract
The article presents the result of the numerical simulation of the turbulent flow for a rib-step system by the RANS method at the Reynolds number, calculated by the step height and average flow rate velocity, Re = 5000. The data obtained in these studies showed the influence of divergence ratio on heat transfer in a flat channel with a transverse rib acting as a vortex generator. It is shown that with an increase in the divergence ratio, the length of the recirculation zone increases, while the position of the heat transfer maximum varies slightly.
Thermal imaging of laminar-turbulent transition on experimental model of swept wing. Creating database of experimental data
Authors: Borodulin V I , Ivanov A V , Mischenko D A 
Published: December 2020

Abstract
The paper is devoted to the problem of creation of experimental database obtained due to systematic extended series of experiments aimed at registering the laminar-turbulent transition in boundary layers on a swept wing model. The experiments were carried out in a low-turbulence wind tunnel in boundary layers developed on ‘suction’ and ‘pressure’ sides of experimental model of an airfoil in a broad range of problem parameters (angle of attack, free-stream velocity, free-stream turbulence etc.). The main feature of performed experiments is using of a new panoramic experimental technique based on application of sensitive infrared camera. Digital postprocessing of obtained thermograms that gave a possibility to detect the position of transition occurred due to amplification of cross-flow instability modes, TS-waves or both of them. The article includes description of the approaches used and the first preliminary results.
Large-eddy simulation of a swirling flow in a model combustion chamber
Authors: Hrebtov M Yu , Palkin E V , Mullyadzhanov R I 
Published: December 2020

Abstract
Large-eddy simulations of the swirling annular jet flow are performed in a model of a combustion chamber at two different flow regimes with and without the central jet at Re = 5000. The mesh convergence study provides well-described time-averaged statistics even for a coarse mesh, while small-scale features are only resolved after a proper refinement. The central jet is shown to significantly modify the recirculation bubble and partially suppress the precessing vortex core.
Numerical investigation of the effect of coherent structures on adiabatic film cooling effectiveness of a flat plate
Authors: Kozyulin N N , Hrebtov M Yu 
Published: December 2020

Abstract
We present a numerical simulation of the flat plate film cooling setup with an elliptical nozzle with a 35° inclination angle. The baseline simulation mimics an experimental setup from [1]. We introduce a modification to the nozzle channel shape by including a backward step with a fixed width, while keeping the nozzle outlet shape fixed. The modification leads to an appearance of a recirculation zone inside the nozzle, which eventually becomes unstable developing a periodic vortex street formation. This change in the flow behaviour improves overall effectiveness of the film cooling by reducing the vertical component and promoting the lateral component of the turbulent diffusion.
Investigation of the influence of the surface material of a streamlined round cylinder on the parameters of the near wake using PIV and POD methods
Authors: Lebedev A S , Dobroselsky K G , Lobasov A S 
Published: December 2020

Abstract
In this paper, the influence of the surface material of a streamlined cylinder on the characteristics of large-scale velocity pulsations is experimentally investigated using the methods of studying the flow structure, namely PIV (Particle Image Velocimetry) and POD (Proper Orthogonal Decomposition). A comparison of the parameters of the near wake in the range of Reynolds numbers of 70 000 – 180 000 is presented for cylinders made of vacuum rubber (hydrophilic material) and fluoroplast (hydrophobic material) of the same diameter. Using the PIV method, instantaneous and averaged velocity fields are obtained. The size of the separation zone is determined based on the average velocity fields. The spatial shape and kinetic energy of the observed large-scale ripples in the wake region are analyzed using the POD statistical method. In the studied range, the transition to the critical flow mode for the fluoroplast cylinder is recorded. For the case of flow around a rubber cylinder, the character of pulsations in the wake zone remains unchanged throughout the studied range.
Numerical and Physical Simulation of Heat Transfer Enhancement Using Vortex Generators
Authors: Mironov A A , Isaev S A , Popov I A , Skrypnik A N , Dushin N S , Mikheev N I 
Published: December 2020

Abstract
Vortex generation and flow disruption in fluid ducts by means of surface modification is a widely used passive heat transfer augmentation technique. The present paper contains the results of numerical and experimental studies of the flow fields and heat transfer enhancement in the ducts with oval-trench and oval-arc shaped dimples applied to the heat transfer surface. The results of the numerical study of the flow over the dimpled surface with periodic boundaries are verified by experimental visualization of the flow and temperature fields. The influence of characteristic geometrical parameters of the dimples on the heat transfer, friction factor, and flow structure in heat-exchange ducts has been obtained. Preliminary results on the artificial neural networks application on heat transfer and friction factor assessment for the flow over dimpled surfaces are presented.
Investigation of the influence of the three-dimensional roughness element on the flow over trapezoidal flying wing
Authors: Pavlenko A M , Kaprilevskaya V S , Kozlov V V 
Published: December 2020

Abstract
The paper is devoted to the investigation of the flow and effects taken place when three-dimensional roughness element is placed on the leading edge of the trapezoidal flying wing. The experimental study was carried out in the working park of the subsonic wind tunnel. Low Reynolds numbers allowed running experiments at in-flight-like conditions. Pictures of the flow structure were obtained by liquid crystal thermography. It was found that longitudinal disturbances on the leading edge and behind three-dimensional roughness element form differently. Inner configuration of the longitudinal structure was shown by hot-wire measurements.