bluuebunny/crossref_metadata_2025_split huggingface dataset:
Joint Survey Processing. II. Stellar Proper Motions in the COSMOS Field from Hubble Space Telescope ACS and Subaru Telescope HSC Observations
Authors: Fajardo-Acosta Sergio B. , Faisst Andreas , Grillmair Carl J. , Chary Ranga-Ram , Paladini Roberta , Rusholme Ben , Stickley Nathaniel 
Published: May 2022

Abstract
We analyze stellar proper motions in the COSMOS field to assess the presence of bulk motions. At bright magnitudes (G-band 18.5–20.76 AB), we use the proper motions of 1010 stars in the Gaia DR2 catalog. At the faint end, we compute proper motions of 11,519 pointlike objects at i-band magnitudes 19–25 AB using Hubble ACS and Subaru HSC data, which span two epochs about 11 yr apart. In order to measure these proper motions with unprecedented accuracy at faint magnitudes, we developed a foundational set of astrometric tools that will be required for joint survey processing of data from the next generation of optical/infrared surveys. The astrometric grids of Hubble ACS and Subaru HSC mosaics were corrected at the catalog level using proper motion–propagated and parallax-corrected Gaia DR2 sources. These astrometric corrections were verified using compact extragalactic sources. Upon comparison of our measured proper motions with Gaia DR2, we estimate the uncertainties in our measurements to be ∼2–3 mas yr−1 axis−1, down to 25.5 AB mag. We correct proper motions for the mean motion of the Sun, and we find that late-type main-sequence stars predominantly in the thin disk in the COSMOS field have space velocities mainly toward the Galactic center. We detect candidate high-velocity (≥220 km s−1) stars, six of them at ∼0.4–6 kpc, from the Gaia sample, and five of them at ∼20 kpc, from the faint star HSC and ACS sample. The sources from the faint star sample may be candidate halo members of the Sangarius stream.
Relating the Diverse Merger Histories and Satellite Populations of Nearby Galaxies
Authors: Smercina Adam , Bell Eric F. , Samuel Jenna , D’Souza Richard 
Published: May 2022

Abstract
We investigate whether the considerable diversity in the satellite populations of nearby Milky Way (MW)-mass galaxies is connected with the diversity in their host’s merger histories. Analyzing eight nearby galaxies with extensive observations of their satellite populations and stellar halos, we characterize each galaxy’s merger history using the metric of its most dominant merger, M
⋆,Dom, defined as the greater of either its total accreted stellar mass or most massive current satellite. We find an unexpectedly tight relationship between these galaxies’ number of M

V
< − 9 satellites within 150 kpc (N
Sat) and M
⋆,Dom. This relationship remains even after accounting for differences in galaxy mass. Using the star formation and orbital histories of satellites around the MW and M81, we demonstrate that both likely evolved along the M
⋆,Dom–N
Sat relation during their current dominant mergers with the Large Magellanic Cloud and M82, respectively. We investigate the presence of this relation in galaxy formation models, including using the Feedback In Realistic Environments (FIRE) simulations to directly compare to the observations. We find no relation between M
⋆,Dom and N
Sat in FIRE, and a universally large scatter in N
Sat with M
⋆,Dom across simulations—in direct contrast with the tightness of the empirical relation. This acute difference in the observed and predicted scaling relation between two fundamental galaxy properties signals that current simulations do not sufficiently reproduce diverse merger histories and their effects on satellite populations. Explaining the emergence of this relation is therefore essential for obtaining a complete understanding of galaxy formation.
Seven Years of SN 2014C: A Multiwavelength Synthesis of an Extraordinary Supernova
Authors: Thomas Benjamin P. , Wheeler J. Craig , Dwarkadas Vikram V. , Stockdale Christopher , Vinkó Jozsef , Pooley David , Xu Yerong , Zeimann Greg , MacQueen Phillip 
Published: May 2022

Abstract
SN 2014C was originally classified as a Type Ib supernova, but at phase ϕ = 127 days, post-explosion strong Hα emission was observed. SN 2014C has since been observed in radio, infrared, optical and X-ray bands. Here we present new optical spectroscopic and photometric data spanning ϕ = 947–2494 days post-explosion. We address the evolution of the broadened Hα emission line, as well as broad [O iii] emission and other lines. We also conduct a parallel analysis of all publicly available multiwavelength data. From our spectra, we find a nearly constant Hα FWHM velocity width of ∼2000 km s−1 that is significantly lower than that of other broadened atomic transitions (∼3000–7000 km s−1) present in our spectra ([O i] λ6300; [O iii] λ
λ4959, 5007; He i
λ7065; [Ca ii] λ
λ7291, 7324). The late radio data demand a fast forward shock (∼10,000 km s−1 at ϕ = 1700 days) in rarified matter that contrasts with the modest velocity of the Hα. We propose that the infrared flux originates from a toroidal-like structure of hydrogen surrounding the progenitor system, while later emission at other wavelengths (radio, X-ray) likely originates predominantly from the reverse shock in the ejecta and the forward shock in the quasi-spherical progenitor He-wind. We propose that the Hα emission arises in the boundary layer between the ejecta and torus. We also consider the possible roles of a pulsar and a binary companion.
The Prospects for Hurricane-like Vortices in Protoplanetary Disks
Authors: Gerbig Konstantin , Laughlin Gregory 
Published: May 2022

Abstract
When ice on the surface of dust grains in protoplanetary disk sublimates, it adds its latent heat of water sublimation to the surrounding flow. Drawing on the analogy provided by tropical cyclones on Earth, we investigate whether this energy source is sufficient to sustain or magnify anticyclonic disk vortices that would otherwise fall victim to viscous dissipation. An analytical treatment, supported by exploratory two-dimensional simulations, suggests that even modestly undersaturated flows can extend the lifetime of vortices, potentially to a degree sufficient to aid particle trapping and planetesimal formation. We expect the best conditions for this mechanism to occur will be found near the disk’s water ice line if turbulent motions displace gas parcels out of thermodynamic equilibrium with the dust midplane.
Kinematics of Parsec-scale Jets of Gamma-Ray Blazars at 43 GHz during 10 yr of the VLBA-BU-BLAZAR Program
Authors: Weaver Zachary R. , Jorstad Svetlana G. , Marscher Alan P. , Morozova Daria A. , Troitsky Ivan S. , Agudo Iván , Gómez José L. , Lähteenmäki Anne , Tammi Joni , Tornikoski Merja 
Published: May 2022

Abstract
We analyze the parsec-scale jet kinematics from 2007 June to 2018 December of a sample of γ-ray bright blazars monitored roughly monthly with the Very Long Baseline Array (VLBA) at 43 GHz under the VLBA-BU-BLAZAR program. We implement a novel piecewise linear fitting method to derive the kinematics of 521 distinct emission knots from a total of 3705 total intensity images in 22 quasars, 13 BL Lacertae objects, and 3 radio galaxies. Apparent speeds of these components range from 0.01c to 78c, and 18.6% of knots (other than the “core”) are quasi-stationary. One-fifth of moving knots exhibit nonballistic motion, with acceleration along the jet within 5 pc of the core (projected) and deceleration farther out. These accelerations occur mainly at locations coincident with quasi-stationary features. We calculate the physical parameters of 273 knots with statistically significant motion, including their Doppler factors, Lorentz factors, and viewing angles. We determine the typical values of these parameters for each jet and the average for each subclass of active galactic nuclei. We investigate the variability of the position angle of each jet over the 10 yr of monitoring. The fluctuations in position of the quasi-stationary components in radio galaxies tend to be parallel to the jet, while no directional preference is seen in the components of quasars and BL Lacertae objects. We find a connection between γ-ray states of blazars and their parsec-scale jet properties, with blazars with brighter 43 GHz cores typically reaching higher γ-ray maxima during flares.
Decreasing False-alarm Rates in CNN-based Solar Flare Prediction Using SDO/HMI Data
Authors: Deshmukh Varad , Flyer Natasha , van der Sande Kiera , Berger Thomas 
Published: May 2022

Abstract
A hybrid two-stage machine-learning architecture that addresses the problem of excessive false positives (false alarms) in solar flare prediction systems is investigated. The first stage is a convolutional neural network (CNN) model based on the VGG-16 architecture that extracts features from a temporal stack of consecutive Solar Dynamics Observatory Helioseismic and Magnetic Imager magnetogram images to produce a flaring probability. The probability of flaring is added to a feature vector derived from the magnetograms to train an extremely randomized trees (ERT) model in the second stage to produce a binary deterministic prediction (flare/no-flare) in a 12 hr forecast window. To tune the hyperparameters of the architecture, a new evaluation metric is introduced: the “scaled True Skill Statistic.” It specifically addresses the large discrepancy between the true positive rate and the false positive rate in the highly unbalanced solar flare event training data sets. Through hyperparameter tuning to maximize this new metric, our two-stage architecture drastically reduces false positives by ≈48% without significantly affecting the true positives (reduction by ≈12%), when compared with predictions from the first-stage CNN alone. This, in turn, improves various traditional binary classification metrics sensitive to false positives, such as the precision, F1, and the Heidke Skill Score. The end result is a more robust 12 hr flare prediction system that could be combined with current operational flare-forecasting methods. Additionally, using the ERT-based feature-ranking mechanism, we show that the CNN output probability is highly ranked in terms of flare prediction relevance.
Three-dimensional Magnetic and Thermodynamic Structures of Solar Microflares
Authors: Li Z. F. , Cheng X. , Chen F. , Chen J. , Ding M. D. 
Published: May 2022

Abstract
Microflares, one of the small-scale solar activities, are believed to be caused by magnetic reconnection. Nevertheless, their three-dimensional (3D) magnetic structures, thermodynamic structures, and physical links to reconnection are unclear. In this Letter, based on a high-resolution 3D radiative magnetohydrodynamic simulation of the quiet Sun spanning from the upper convection zone to the corona, we investigate the 3D magnetic and thermodynamic structures of three homologous microflares. It is found that they originate from localized hot plasma embedded in the chromospheric environment at the height of 2–10 Mm above the photosphere and last for 3–10 minutes with released magnetic energy in the range of 1027–1028 erg. The heated plasma is almost cospatial with the regions where the heating rate per particle is maximal. The 3D velocity field reveals a pair of converging flows with velocities of tens of km s−1 moving toward and outflows with velocities of about 100 km s−1 moving away from the hot plasma. These features support magnetic reconnection playing a critical role in heating the localized chromospheric plasma to coronal temperature, giving rise to the observed microflares. The magnetic topology analysis further discloses that the reconnection region is located near quasi-separators where both current density and squashing factors are maximal although the specific topology may vary from a tether-cutting to fan-spine-like structure.
Multipoint Analysis of the Interaction between a Shock and an ICME-like Structure around 2011 March 22
Authors: Xu Mengjiao , Shen Chenglong , Wang Can , Chi Yutian , Zhong Zhihui , Wang Yuming 
Published: May 2022

Abstract
This work reports on the interaction between a fast forward shock and an interplanetary coronal-mass-ejection-like structure (ICMELS) as observed by in situ observations of radially aligned spacecraft. Around 2011 March 22, the Venus EXpress (VEX) and Solar TErrestrial RElations Observatory-A (STEREO-A) were nearly at the same longitude, providing us with an excellent opportunity to study the formation and evolution of the complex structures. The shock and ICMELS investigated in this paper are isolated near Venus, but when they approach STEREO-A, the shock nearly approaches the front edge of the ICMELS and forms a shock–ICMELS complex structure. The maximal magnetic field in the ICMELS increased 2.3 times due to shock compression, according to the observation. The recovery model, which restores the shocked portion of the shock–ICMELS to its uncompressed condition, likewise confirms this improvement. The interaction with the ICMELS, on the other hand, weakens shock 2. The magnetic compression ratio falls from 2.4 at Venus to 2.0 at STEREO-A. This research enables us to have a better physical knowledge of the impacts of the interaction between a shock and an ICME (or ICMELS), which will aid future space weather predictions.
Interdisciplinarity of scientific production on hate speech and social media: A bibliometric analysis
Authors: Ramírez-García Antonia , González-Molina Antonio , Gutiérrez-Arenas María-del-Pilar , Moyano-Pacheco Manuel 
Published: May 2022

The impact of hate speech, both on a personal and social level, has increased due to social media. This has made it the focus of interest of numerous scientific journals, which increases the visibility of this global problem. The aim of this research is to analyse the basic descriptive metrics of the scientific production on hate speech and social media, as well as to explore the interdisciplinarity of these approaches. A bibliometric study has been carried out on the basis of the works indexed in the Scopus database related to the binomial ‘hate speech’ and ‘social media’ over a period of 20 years (2001 to 2020). The metrics used show that it is from 2017 onwards when this topic begins to arouse greater interest among researchers and that they constitute a sufficient indicator to consider the topic as one of interest to the scientific community. The joint research between both concepts raises its quality levels from a strictly metric point of view. ‘Computer Science’ and ‘Social Sciences’ are the two areas that clearly define the scientific production on this subject. The inversion of percentages in terms of the areas of origin of the works and citations in these two areas, is evidence of this interdisciplinarity. The indicators obtained show the relevance and transcendence of a social problem in the face of which proactive measures must be implemented.
Las repercusiones que tiene el discurso del odio, tanto a nivel personal como social, se han intensificado con las redes sociales. Esto lo ha convertido en centro de interés de numerosas revistas científicas, lo que incrementa la visibilización de esta problemática global. El objetivo de esta investigación es analizar las métricas básicas descriptivas de la producción científica sobre el discurso del odio y redes sociales, así como explorar la interdisciplinariedad de estos enfoques. Se ha llevado a cabo un estudio bibliométrico a partir de trabajos indexados en la base de datos Scopus relacionados con el binomio «discurso de odio» y «redes sociales», en un período temporal de 20 años (2001 a 2020). Las métricas utilizadas demuestran que, a partir del año 2017, esta temática comienza a despertar mayor interés entre los investigadores, constituyéndose un indicador suficiente para considerar el tema como de interés por parte de la comunidad científica. La investigación conjunta entre ambos conceptos eleva sus niveles de calidad desde un punto de vista estrictamente métrico. Las áreas «Computer Science» y «Social Sciences» son las dos que definen claramente la producción científica sobre este tema. La inversión de porcentajes en cuanto a áreas de procedencia de los trabajos y citas en estas dos áreas evidencian esta interdisciplinariedad. Los indicadores obtenidos muestran la relevancia y trascendencia de un problema social ante el que se deben implementar medidas proactivas.
Assessing Conservation Potential of Streams for Spikedace and Loach Minnow Using Species Distribution Modeling
Authors: Hickerson Brian T. , Booher Evan C.J. , Grube Elizabeth R. , Robinson Anthony T. 
Published: May 2022

AbstractIdentifying, evaluating, and prioritizing freshwater systems for conservation is a persistent challenge for managers tasked with conservation and recovery of native fishes. We used historical records from the Gila River basin, the national hydrography data set, and Random Forest modeling to predict probability of Spikedace Meda fulgida and Loach Minnow Rhinichthys cobitis occurrence throughout their range in the Gila River basin. Models for both species performed moderately well, with relatively high predicted probability of occurrence at streams with historical records. Predicted probability of occurrence was also relatively high in several streams without historical records of focal species, suggesting that there are unoccupied reaches throughout the Gila River basin with similar environmental conditions to historically occupied reaches for both species. Unoccupied reaches with the highest predicted probability of occurrence may have a greater chance of supporting translocated populations of focal species. Our results can be used as a first step for locating reaches most likely to support translocated populations of Spikedace and Loach Minnow within their respective historical ranges. Our approach may be applicable to other species of conservation concern with available historic records in need of population restoration.
DESAFIOS ENFRENTADOS NO ENSINO EMERGENCIAL REMOTO DE QUÍMICA: UMA PERSPECTIVA DO ALUNO
Authors: Bulhões Felina Kelly Marques , Santana Mayana Valentin , Lira Francielle Milton , Rego Enoc Lima do 
Published: May 2022

A pandemia do SARs-CoV-2 e o distanciamento social trouxe muitos impactos à formação dos estudantes de graduação afetando, principalmente, os ingressantes na universidade. Desta forma, essa pesquisa teve como objetivo identificar os fatores que dificultam a aprendizagem na disciplina de Química pelos estudantes dos cursos de graduação em Licenciatura em Ciências Biológicas e Engenharia Agronômica da Universidade do Estado da Bahia, campus IX, durante o ensino remoto emergencial causado pela COVID-19. Esse estudo foi conduzido através da estratégia Websurvey, com a participação de 29 estudantes selecionados aleatoriamente. O questionário foi estruturado com perguntas fechadas e abertas divididas em duas seções, onde a primeira referente às características sóciodemográficas dos participantes e a segunda seção com questões relacionadas às dificuldades vivenciadas em decorrência do ensino remoto emergencial. Os resultados apontaram que a maioria dos estudantes, provenientes de escolas públicas, apresentaram dificuldades na disciplina de Química na graduação. Essas dificuldades, que em parte, está relacionada a ausência de aprendizagem significativa na educação básica, foi agravada pelos desafios enfrentados pelos discentes durante o Ensino Remoto Emergencial. Elencando os fatores que dificultam a aprendizagem na disciplina de Química durante o ensino remoto emergencial, pode-se citar internet de péssima qualidade, equipamentos precários, ambiente familiar inadequado e poucas familiaridades com as tecnologias.
A Pilot Study Regarding The Consequences of The COVID-19 Pandemic on Healthcare Education in India and the Implications
Authors: Sharma Paras , Chowdhury Kona , Kumar Santosh , Bhatt Rohan , Hirani Tanvi , Duseja Shilpa , Haque Mainul , Lutfor Afzalunnessa Binte , Etando Ayukafangha , Škrbić Ranko , Shahwan Moyad , Jairoun Ammar Abdulrahman , Godman Brian 
Published: May 2022

Introduction:
The early approaches to prevent the spread of COVID-19 included lockdown and social distancing measures, leading to university closures. These measures forced unparalleled changes to the delivery of healthcare education. Concerns included the preparedness of faculty and students to e-learning as well as the routine availability and funding of equipment and internet bundles. This needed addressing with fully trained healthcare professionals required given rising inappropriate use of antibiotics in India, growing prevalence of non-communicable diseases as well as an increasing number of patients with joint comorbidities. Consequently, there is a need to ascertain the current impact of the pandemic on healthcare student education across India.

Materials and Methods:
This was a pilot study among 10 purposely selected healthcare educators in both private and public universities. The questionnaire built on published studies.

Results:
Identified challenges included a lack of familiarity with online education, no bedside teaching, lack of equipment and affordability of internet bundles, poor internet connectivity and postponed examinations. Ways forward included training faculty on e-learning, providing students with loans and other financial support to purchase equipment and internet bundles, establishing COVID-19 prevention protocols and protective equipment, recording lectures and tutorials to make up for lost time and simulated methods to teach clinical aspects.

Conclusion:
Despite challenges, there was a rapid move to online learning among surveyed universities. Alongside this, courses to address lack of familiarity with e-learning approaches with hybrid teaching approaches here to stay. The next step will be to undertake a wider study and to use the combined findings to provide future guidance.
Volume Index is a Risk Factor for Recurrence Even in Patients with Clinical Stage IA Endometrial Cancer Undergoing either Laparotomy or Laparoscopy
Authors: Chikazawa Kenro , Netsu Sachiho , Imai Ken , Kimura Azusa , Kuwata Tomoyuki , Konno Ryo 
Published: May 2022

Objectives:
The objective of the study was to investigate the long-term outcomes, in particular, recurrence risk, especially tumor volume, for Stage IA endometrial cancer and to identify the risk factors for recurrence.

Materials and Methods:
This single-center retrospective study analyzed women who underwent primary surgical treatment for the International Federation of Gynecology and Obstetrics Stage IA (Grade 1 or 2) endometrioid carcinoma at our institute between January 2010 and July 2018. Patients' demographic characteristics, including age, operative time, number of lymph nodes, final stage, volume index as tumor volume, and final histological type, were reviewed. A total of 168 patients were enrolled, with 95 and 73 patients in the laparotomy and laparoscopy groups, respectively. The Cox proportional hazards model was used to adjust for prognostic factors in the analysis including upstaged patients, tumor histology, lymphovascular invasion, and volume index.

Results:
There was no difference in the recurrence rate between laparoscopic and open surgeries for Stage IA endometrial cancer. The operative time was longer, and the amount of blood loss was lesser in the laparoscopy group than in the laparotomy group. For all patients undergoing either laparoscopy or open surgery, upstaged ≥IB, nonendometrioid Grade 1 or 2, lymphovascular invasion, and volume index ≥36 were significant independent recurrence risk factors.

Conclusion:
Laparoscopic surgery for Stage IA endometrial cancer is technically and oncologically safe. Patients with a high-volume index have a higher recurrence risk. Furthermore, the volume index can be a recurrence predictor in low-risk endometrial cancer patients.