bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Crab Pulsar: Origin of the Crab Nebula’s Radio Pairs
Authors: Coroniti F. V. 
Published: February 2019

Abstract
Previously, we constructed a model—essentially a plausibility argument—in which the Crab Pulsar produces a spatially separated ion dominated and pair plasma dominated, magnetically striped relativistic wind, with the ion wind’s kinetic energy and electromagnetic Poynting fluxes being comparable. In this paper, the polar cap ion–photon pair production of that model is replaced with pair production by ion curvature synchrotron photons. The first primary ion curvature photons, and, contrary to conventional wisdom, also the first primary electron curvature photons, do not immediately convert into pairs. The primary beam particles continue to accelerate, and the actual photons that convert into pairs, which then short out the parallel electric field and terminate the acceleration, are produced by the further accelerated, higher energy particles. Simple estimates of the ensuing pair production cascade give pair multiplicities—the number of pairs per primary beam particle—of M
± ≈ 6–8 × 104, comparable to standard calculations, but much less than the 3 × 106 value deduced by Rees and Gunn in order to sustain the Crab Nebula’s N
± ≈ 1051 radio-emitting pairs against adiabatic expansion energy losses. Using a simple spin-down evolution model for the pulsar’s rotation frequency, the time-integrated pair cascade production driven by the primary ion beam can produce the N
± ≈ 1051 radio pairs, whereas the primary electron beam produces about an order of magnitude fewer pairs.
The Origin of r-process Enhanced Metal-poor Halo Stars In Now-destroyed Ultra-faint Dwarf Galaxies
Authors: Brauer Kaley , Ji Alexander P. , Frebel Anna , Dooley Gregory A. , Gómez Facundo A. , O’Shea Brian W. 
Published: February 2019

Abstract
The highly r-process-enhanced (r-II) metal-poor halo stars we observe today could play a key role in understanding early ultra-faint dwarf galaxies (UFDs), the smallest building blocks of the Milky Way. If a significant fraction of metal-poor r-II halo stars originated in the UFDs that merged to help form the Milky Way, observations of r-II stars could help us study these now-destroyed systems and probe the formation history of our Galaxy. To conduct our initial investigation into this possible connection, we use high-resolution cosmological simulations of Milky Way-mass galaxies from the Caterpillar suite in combination with a simple, empirically motivated treatment of r-process enrichment. We determine the fraction of metal-poor halo stars that could have formed from highly r-process-enhanced gas in now-destroyed low-mass UFDs, the simulated r-II fraction, and compare it to the “as observed” r-II fraction. We find that the simulated fraction, f
r−II,sim ∼ 1%–2%, can account for around half of the “as observed” fraction, f
r−II,obs ∼ 2%–4%. The “as observed” fraction likely overrepresents the fraction of r-II stars due to incomplete sampling, though, meaning f
r−II,sim likely accounts for more than half of the true f
r−II,obs. Further considering some parameter variations and scatter between individual simulations, the simulated fraction can account for around 20%–80% of the “as observed” fraction.
The Atmospheric Circulation and Climate of Terrestrial Planets Orbiting Sun-like and M Dwarf Stars over a Broad Range of Planetary Parameters
Authors: Komacek Thaddeus D. , Abbot Dorian S. 
Published: February 2019

Abstract
The recent detections of temperate terrestrial planets orbiting nearby stars and the promise of characterizing their atmospheres motivate a need to understand how the diversity of possible planetary parameters affects the climate of terrestrial planets. In this work, we investigate the atmospheric circulation and climate of terrestrial exoplanets orbiting both Sun-like and M dwarf stars over a wide swath of possible planetary parameters, including the planetary rotation period, surface pressure, incident stellar flux, surface gravity, planetary radius, and cloud particle size. We do so using a general circulation model (GCM) that includes nongray radiative transfer and the effects of clouds. The results from this suite of simulations generally show qualitatively similar dependencies of circulation and climate on planetary parameters to idealized GCMs, with quantitative differences due to the inclusion of additional model physics. Notably, we find that the effective cloud particle size is a key unknown parameter that can greatly affect the climate of terrestrial exoplanets. We confirm a transition between low and high dayside cloud coverage of synchronously rotating terrestrial planets with increasing rotation period. We determine that this cloud transition is due to eddy-driven convergence near the substellar point and should not be parameterization dependent. Finally, we compute full-phase light curves from our simulations of planets orbiting M dwarf stars, finding that changing incident stellar flux and rotation period affect observable properties of terrestrial exoplanets. Our GCM results can guide expectations for planetary climate over the broad range of possible terrestrial exoplanets that will be observed with future space telescopes.
The Period Change of Cyg X-3
Authors: Antokhin Igor I. , Cherepashchuk Anatol M. 
Published: February 2019

Abstract
By using available archival X-ray data, we significantly extended the list of times of X-ray minima. The new list includes 65 data points obtained by critically reanalyzing RXTE ASM data, 88 data points based on observations by MAXI, and 2 data points based on observations by SUZAKU and AstroSat. Analyzing the data along with times of X-ray minima available from the literature, we provide the most accurate estimate of the rate of period change to date. We do not confirm the existence of a second derivative of the orbital period suggested by some authors earlier. Instead, we find that the changes in the period can be fit by a sum of quadratic and sinusoidal functions. The period of sinusoidal variations is 15.79 yr. They can be related either to apsidal motion in the close binary with eccentricity e ≃ 0.03 or to the presence of a third body with a mass of about 0.7 M
⊙ located at a distance ∼16 au from the close binary.
JCMT POL-2 and ALMA Polarimetric Observations of 6000–100 au Scales in the Protostar B335: Linking Magnetic Field and Gas Kinematics in Observations and MHD Simulations
Authors: Yen Hsi-Wei , Zhao Bo , Hsieh I-Ta , Koch Patrick , Krasnopolsky Ruben , Lee Chin-Fei , Li Zhi-Yun , Liu Sheng-Yuan , Ohashi Nagayoshi , Takakuwa Shigehisa , Tang Ya-Wen 
Published: February 2019

Abstract
We present our analysis of the magnetic field structures from 6000 to 100 au scales in the Class 0 protostar B335 inferred from our James Clerk Maxwell telescope (JCMT) POL-2 observations and ALMA archival polarimetric data. To interpret the observational results, we perform a series of (non)ideal MHD simulations of the collapse of a rotating nonturbulent dense core, whose initial conditions are adopted to be the same as observed in B335, and generate synthetic polarization maps. The comparison of our JCMT and simulation results suggests that the magnetic field on a 6000 au scale in B335 is pinched and well aligned with the bipolar outflow along the east–west direction. Among all our simulations, the ALMA polarimetric results are best explained with weak magnetic field models having an initial mass-to-flux ratio of 9.6. However, we find that with a weak magnetic field, the rotational velocity on a 100 au scale and the disk size in our simulations are larger than the observational estimates by a factor of several. An independent comparison of our simulations and the gas kinematics in B335 observed with the SMA and ALMA favors strong magnetic field models with an initial mass-to-flux ratio smaller than 4.8. We discuss two possibilities resulting in the different magnetic field strengths inferred from the polarimetric and molecular-line observations: (1) overestimated rotational-to-gravitational energy in B335, and (2) additional contributions in the polarized intensity due to scattering on a 100 au scale.
Cosmic Pathways for Compact Groups in the Milli-Millennium Simulation
Authors: Tzanavaris P. , Gallagher S. C. , Ali S. , Miller D. R. , Pentinga S. , Johnson K. E. 
Published: February 2019

Abstract
We detected 10 compact galaxy groups (CGs) at z = 0 in the semianalytic galaxy catalog of Guo et al. for the milli-Millennium Cosmological Simulation (sCGs in mGuo2010a). We aimed to identify potential canonical pathways for compact group evolution and thus illuminate the history of observed nearby CGs. By constructing merger trees for z = 0 sCG galaxies, we studied the cosmological evolution of key properties and compared them with z = 0 Hickson CGs (HCGs). We found that, once sCG galaxies come within 1 (0.5) Mpc of their most massive galaxy, they remain within that distance until z = 0, suggesting sCG “birth redshifts.” At z = 0 stellar masses of sCG most massive galaxies are within 1010 ≲ M
*/M
⊙ ≲ 1011. In several cases, especially in the two four- and five-member systems, the amount of cold gas mass anticorrelates with stellar mass, which in turn correlates with hot gas mass. We define the angular difference between group members’ 3D velocity vectors, Δθ
vel, and note that many of the groups are long-lived because their small values of Δθ
vel indicate a significant parallel component. For triplets in particular, Δθ
vel values range between 20° and 40° so that galaxies are coming together along roughly parallel paths, and pairwise separations do not show large pronounced changes after close encounters. The best agreement between sCG and HCG physical properties is for M
* galaxy values, but HCG values are higher overall, including for star formation rates (SFRs). Unlike HCGs, due to a tail at low SFR and M
* and a lack of M
* ≳ 1011
M
⊙ galaxies, only a few sCG galaxies are on the star-forming main sequence.
The Accretion History of AGNs. I. Supermassive Black Hole Population Synthesis Model
Authors: Tasnim Ananna Tonima , Treister Ezequiel , Megan Urry C. , Ricci C. , Kirkpatrick Allison , LaMassa Stephanie , Buchner Johannes , Civano Francesca , Tremmel Michael , Marchesi Stefano 
Published: February 2019

Abstract
As matter accretes onto the central supermassive black holes in active galactic nuclei (AGNs), X-rays are emitted. We present a population synthesis model that accounts for the summed X-ray emission from growing black holes; modulo the efficiency of converting mass to X-rays, this is effectively a record of the accreted mass. We need this population synthesis model to reproduce observed constraints from X-ray surveys: the X-ray number counts, the observed fraction of Compton-thick AGNs [log (N
H/cm−2) > 24], and the spectrum of the cosmic X-ray background (CXB), after accounting for selection biases. Over the past decade, X-ray surveys by XMM-Newton, Chandra, NuSTAR, and Swift-BAT have provided greatly improved observational constraints. We find that no existing X-ray luminosity function (XLF) consistently reproduces all these observations. We take the uncertainty in AGN spectra into account and use a neural network to compute an XLF that fits all observed constraints, including observed Compton-thick number counts and fractions. This new population synthesis model suggests that, intrinsically, 50% ± 9% (56% ± 7%) of all AGNs within z ≃ 0.1 (1.0) are Compton-thick.
The HLKES-2: Revision and Evaluation of the Health Literacy Knowledge and Experiences Survey
Authors: Walker Danielle , Howe Carol , Dunkerley Marion , Deupree Joy , Cormier Catherine 
Published: February 2019

Background:
Low health literacy impacts individual health and the health care system. The Health Literacy Knowledge and Experience Survey (HLKES) was created to evaluate preparedness of nurses to provide health literate care. However, the instrument was developed a decade ago and needs revision. The purpose of this study was to update and shorten the HLKES into a feasible, valid, and reliable instrument.

Method:
The HLKES was refined into a 14-item instrument (10 knowledge questions and four experience questions). Expert review was obtained. Face validity was assessed, and pilot and field testing with students was conducted.

Results:
Scale content validity index was 0.95, and individual questions demonstrated appropriate item difficulty and discrimination. Cronbach's alpha coefficient was .565 for the 10 multiple choice questions and .843 for the four Likert-type questions, indicating good reliability.

Conclusion:

A reliable and valid HLKES-2 was developed to evaluate health literacy knowledge and experiences in a contemporary setting.

[
J Nurs Educ
. 2019;58(2):86–92.]
Developing a Cultural Immersion Service-Learning Experience for Undergraduate Nursing Students
Authors: Alexander-Ruff Julie H. , Kinion Elizabeth S. 
Published: February 2019

Background:
Cultural consciousness is a central element of purposeful and appropriate health care delivery. Research suggests that cultural consciousness is strengthened through self-reflection, dialogue about race, and experience within other cultures.

Method:
Two cohorts of senior-level nursing students participated in a 1-week cultural immersion service-learning (CISL) experience in an isolated, rural American Indian community. Student reflections and White Racial Identity Attitude Scale (WRIAS) data were collected and analyzed.

Results:

The CISL experience facilitated culturally conscious care in two thirds of the participating nursing students. Differences in WRIAS scores were statistically significant (
p
< .0001) with an effect size of 1.9.

Conclusion:

Implementing CISL experiences into the undergraduate curriculum may help nursing students recognize societal privilege and improve cultural consciousness. Recommendations are provided to assist nurse educators to develop partnerships with indigenous nations, which make CISL experiences possible.

[
J Nurs Educ.
2019;58(2):117–120.]
Topographic Changes After Hyperopic LASIK With the SCHWIND ESIRIS Laser Platform
Authors: de Ortueta Diego , Arba-Mosquera Samuel , Baatz Holger 
Published: February 2019

Purpose:
To analyze and compare refractive power changes with topographic changes after hyperopic LASIK using the ESIRIS laser platform.

Methods:
Sixty-six consecutive eyes of 37 patients were evaluated retrospectively. Outcomes were evaluated at 3 months. In all cases, standard examinations including pre- and postoperative topographic and corneal wavefront analysis with a Keratron topographer were performed. Preoperative mean spherical equivalent was +2.74 diopters (D) with a mean cylinder of 0.67 D. The ESIRIS excimer laser system was used to perform ablations. Topographic changes of Maloney index, simulated keratometry (sim-K), and K-reading at 5 and 7 mm were evaluated.

Results:
Ninety-two percent of eyes were within ±0.50 D manifest refraction at 3 months postoperatively. Changes in refraction, Maloney indices, and sim-K indices after surgery were strongly correlated with the intended correction. Induction of negative corneal spherical aberrations and increased prolate asphericity was correlated with the achieved defocus correction. No other Zernike mode was significantly correlated. Topographically, an overcorrection within the central 3 mm and a gradual peripheral undercorrection also was observed.

Conclusions:

Analyzing the topographic maps, the corneal power change of the Maloney indices correlated with the intended correction. After hyperopic LASIK, an overcorrection was observed in the 3-mm central zone, and progressive undercorrections were observed in the 5-and 7-mm zones. [
J Refract Surg.
2008;24:137–144.]
Inadequate Results for Microkeratomeassisted Additive Stromal Keratoplasty for Management of Keratoconus
Authors: Coullet Julien , Fournié Pierre , Malecaze François , Arné Jean-Louis 
Published: February 2019

Purpose:
To evaluate a new automated technique— microkeratome-assisted additive stromal keratoplasty (MASK)—for the management of keratoconus in eyes scheduled for surgery with clear cornea associated with total contact lens intolerance.

Methods:
This non-comparative, interventional case series included four eyes of four patients with stage I and II keratoconus associated with total contact lens intolerance. The first step of the surgical procedure consisted of performing a nasal-hinged flap on the host cornea with a microkeratome. The second step consisted of extracting a stromal plano-powered disk from the donor's cornea using an artificial chamber. The 80-μm thick lamellar graft was punched with a 7.5-mm circular trephine and positioned beneath the flap. Corneal refractive surgery was scheduled for the end of the sixth postoperative month.

Results:
No corneal refractive surgery was performed after 6 months of follow-up. Only one eye gained five lines of best spectacle-corrected visual acuity (BSCVA). Among the other three eyes, two had unchanged BSCVA and one lost one line of BSCVA. At the end of surgery, mean corneal thickness was increased by 148.75 μm.

Conclusions:

Microkeratome-assisted additive stromal keratoplasty appears to be a safe and straightforward surgical technique that preserves the host endothelium and avoids the need of an open-sky procedure. However, in our study, MASK is not considered as an alternative to penetrating or deep lamellar keratoplasty in the management of keratoconus with clear cornea because of imprecise anatomic and refractive outcomes. [
J Refract Surg.
2008;24:166–172.]
Comparison of Silicone and Non-silicone Hydrogel Soft Contact Lenses Used as a Bandage After LASEK
Authors: Gil-Cazorla Raquel , Teus Miguel A. , Arranz-Márquez Esther 
Published: February 2019

Purpose:
To evaluate two different soft contact lens materials for continuous-wear bandage contact lenses after laser epithelial keratomileusis (LASEK).

Methods:

A prospective, observer-masked study was conducted of 32 eyes of 16 consecutive patients. Inclusion criteria were candidates for bilateral LASEK, myopia of ⩽−6.00 diopters (D), astigmatism <−1.50 D, and bilateral best spectacle-corrected visual acuity of 20/20 or better. Patients were randomly selected for a balafilcon A (PureVision; Bausch & Lomb) bandage contact lens in one eye and a poly-2-hydroxyethylmethacrylate-co-methacrylate glycerol (EquiS 60; mark'ennovy) in the fellow eye. Corneal epithelial status, conjunctival and limbal hyperemia, lens movement, contact lens debris, and the responses to a subjective comfort questionnaire were assessed postoperatively. The parameters were evaluated preoperatively and 1 and 5 days postoperatively. Paired Student
t
test and chi-square tests were used when appropriate.

Results:

Thirty-two eyes of 16 consecutive patients who underwent LASEK to correct low to moderate myopia were analyzed. The mean spherical equivalent refraction was −3.25 D. There was no difference in conjunctival or limbal hyperemia, contact lens debris, or subjective comfort between lenses at any postoperative visit. In contrast, the corneal epithelial status was statistically better in the eyes with a silicone bandage contact lens 5 days after LASEK (
P
=.01).

Conclusions:

The results suggest that the bandage contact lens material used after LASEK affects the corneal epithelial healing process. [
J Refract Surg.
2008;24:199–203.]
Distributed Health Literacy in the Maternal Health Context in Vietnam
Authors: McKinn Shannon , Linh Duong Thuy , Foster Kirsty , McCaffery Kirsten 
Published: February 2019

Background:
Previous health literacy research has often focused on individual functional health literacy, ignoring the cultural contexts through which many people experience health care.

Objective:
We aimed to explore the nature of maternal health literacy among ethnic minority women in a low-resource setting in Vietnam.

Methods:
Using a qualitative approach, we conducted focus groups with 42 pregnant women, mothers, and grandmothers of children younger than age 5 years from the Thai and Hmong ethnic groups. Semi-structured interviews were conducted with key informants and thematic analysis was performed.

Key Results:
The findings of our thematic analysis aligned well with the concept of distributed health literacy. We found that ethnic minority women drew upon family and social networks of health literacy mediators to share knowledge and understanding, assess and evaluate information, communicate with health professionals, and support decision-making. Family members were also involved in making health decisions that had the potential to negatively affect women and children's health.

Conclusions:

Family members are an important source of information for ethnic minority women, and they influence decision-making. Relatives and husbands of pregnant women could be included in maternal health education programs to potentially strengthen the health literacy of the whole community. The distributed health literacy concept can be used to strengthen health promotion messages and to reduce the risk of negative health outcomes.

[
HLRP: Health Literacy Research and Practice
. 2019;3(1):e31–e42.]

Plain Language Summary:
Distributed health literacy refers to how health literacy skills and practices are distributed through social networks. This concept applies well to the maternal health context in Vietnam. Older women are trusted sources of information, and family influences decision-making during pregnancy. Women's limited autonomy increases the importance of family involvement. Distributed health literacy could be used to strengthen health promotion messages.
Le monumentalisme funéraire récent d’Éthiopie et la question des démocraties primitives
Authors: Gallay Alain 
Published: February 2019

Cet article est la continuation des réflexions présentées dans le cadre de la rencontre du « groupe de Strasbourg » en 2015 à propos du mégalithisme éthiopien et voudrait approfondir la question des relations entre la notion de démocratie primitive et le concept de classe aristocratique développé par A. Jensen (1936). La compréhension de ces questions nécessite que l’on explicite un certain nombre de concepts anthropologiques théoriques relevant du politique, notamment celui de démocratie primitive proposé par Alain Testart. Le monumentalisme funéraire konso ne peut se comprendre que dans le cadre d’une certaine hiérarchisation de la société qui repose sur des prérogatives guerrières ou religieuses, dominantes selon les circonstances historiques. On distingue les pierres dressées sur les places des villages des tombes avec statues de bois, les waaka, qui concernent soit des guerriers renommés faisant figure de héros, soit des poqolla, actuellement chefs religieux écartés du métier des armes. La monographie d’A. Jensen (1936) pose néanmoins un problème d’interprétation difficile car elle présente les poqolla comme formant une aristocratie tirant sa légitimité de ses prouesses guerrières et de ses fonctions religieuses, ce qui paraît en contradiction avec la situation actuelle et le concept de démocratie primitive. Deux populations de langue omotique, les Gamo et les Jem, permettent d’élargir le débat. Sur une base cladistique est proposée une structure dynamique des sociétés considérées reposant sur dix pas de transformation. Cette structure débouche au plan historique sur une corrélation possible entre la hiérarchisation observée par A. Jensen chez les Konso et le développement de l’esclavage de traite. Cette proposition théorique est compatible avec l’anthropologie sociale des populations locales et africaines et du contexte historique récent.