bluuebunny/crossref_metadata_2025_split huggingface dataset:
Near L-edge Single and Multiple Photoionization of Triply Charged Iron Ions
Authors: Beerwerth Randolf , Buhr Ticia , Perry-Sassmannshausen Alexander , Stock Sebastian O. , Bari Sadia , Holste Kristof , Kilcoyne A. L. David , Reinwardt Simon , Ricz Sandor , Savin Daniel Wolf , Schubert Kaja , Martins Michael , Müller Alfred , Fritzsche Stephan , Schippers Stefan 
Published: December 2019

Abstract
Relative cross sections for m-fold photoionization (m = 1,…, 5) of Fe3+ by single-photon absorption were measured employing the photon-ion merged-beams setup PIPE at the PETRA III synchrotron light source operated at DESY in Hamburg, Germany. The photon energies used spanned the range of 680–950 eV, covering both the photoexcitation resonances from the 2p and 2s shells, as well as the direct ionization from both shells. Multiconfiguration Dirac–Hartree–Fock (MCDHF) calculations were performed to simulate the total photoexcitation spectra. Good agreement was found with the experimental results. These computations helped to assign several strong resonance features to specific transitions. We also carried out Hartree–Fock calculations with relativistic extensions taking into account both photoexcitation and photoionization. Furthermore, we performed extensive MCDHF calculations of the Auger cascades that result when an electron is removed from the 2p and 2s shells of Fe3+. Our theoretically predicted charge-state fractions are in good agreement with the experimental results, representing a substantial improvement over previous theoretical calculations. The main reason for the disagreement with the previous calculations is their lack of inclusion of slow Auger decays of several configurations that can only proceed when accompanied by de-excitation of two electrons. In such cases, this additional shake-down transition of a (sub)valence electron is required to gain the necessary energy for the release of the Auger electron.
Synthetic Large-scale Galactic Filaments: On Their Formation, Physical Properties, and Resemblance to Observations
Authors: Zucker Catherine , Smith Rowan , Goodman Alyssa 
Published: December 2019

Abstract
Using a population of large-scale filaments extracted from an AREPO simulation of a Milky Way–like galaxy, we seek to understand the extent to which observed large-scale filament properties (with lengths ≳100 pc) can be explained by galactic dynamics alone. From an observer’s perspective in the disk of the galaxy, we identify filaments forming purely due to galactic dynamics, without the effects of feedback or local self-gravity. We find that large-scale galactic filaments are intrinsically rare, and we estimate that at maximum approximately one filament per kpc2 should be identified in projection, when viewed from the direction of our Sun in the Milky Way. In this idealized scenario, we find filaments in both the arm and interarm regions and hypothesize that the former may be due to gas compression in the spiral potential wells, with the latter due to differential rotation. Using the same analysis pipeline applied previously to observations, we analyze the physical properties of large-scale galactic filaments and quantify their sensitivity to projection effects and galactic environment (i.e., whether they lie in the arm or interarm regions). We find that observed “Giant Molecular Filaments” are consistent with being non-self-gravitating structures dominated by galactic dynamics. Straighter, narrower, and denser “Bone-like” filaments, like the paradigmatic Nessie filament, have similar column densities, velocity gradients, and galactic plane heights (z ≈ 0 pc) to those in our simple model, but additional physical effects (such as feedback and self-gravity) must be invoked to explain their lengths and widths.
Evidence for Late-stage Eruptive Mass Loss in the Progenitor to SN2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a Rapidly Rising Luminous Transient
Authors: Ho Anna Y. Q. , Goldstein Daniel A. , Schulze Steve , Khatami David K. , Perley Daniel A. , Ergon Mattias , Gal-Yam Avishay , Corsi Alessandra , Andreoni Igor , Barbarino Cristina , Bellm Eric C. , Blagorodnova Nadia , Bright Joe S. , Burns E. , Cenko S. Bradley , Cunningham Virginia , De Kishalay , Dekany Richard , Dugas Alison , Fender Rob P. , Fransson Claes , Fremling Christoffer , Goldstein Adam , Graham Matthew J. , Hale David , Horesh Assaf , Hung Tiara , Kasliwal Mansi M. , M. Kuin N. Paul , Kulkarni S. R. , Kupfer Thomas , Lunnan Ragnhild , Masci Frank J. , Ngeow Chow-Choong , Nugent Peter E. , Ofek Eran O. , Patterson Maria T. , Petitpas Glen , Rusholme Ben , Sai Hanna , Sfaradi Itai , Shupe David L. , Sollerman Jesper , Soumagnac Maayane T. , Tachibana Yutaro , Taddia Francesco , Walters Richard , Wang Xiaofeng , Yao Yuhan , Zhang Xinhan 
Published: December 2019

Abstract
We present detailed observations of ZTF18abukavn (SN2018gep), discovered in high-cadence data from the Zwicky Transient Facility as a rapidly rising (1.4 ± 0.1 mag hr−1) and luminous (

mag) transient. It is spectroscopically classified as a broad-lined stripped-envelope supernova (Ic-BL SN). The high peak luminosity (

), the short rise time (

in g band), and the blue colors at peak (

) all resemble the high-redshift Ic-BL iPTF16asu, as well as several other unclassified fast transients. The early discovery of SN2018gep (within an hour of shock breakout) enabled an intensive spectroscopic campaign, including the highest-temperature (

) spectra of a stripped-envelope SN. A retrospective search revealed luminous (

mag) emission in the days to weeks before explosion, the first definitive detection of precursor emission for a Ic-BL. We find a limit on the isotropic gamma-ray energy release

, a limit on X-ray emission

, and a limit on radio emission

. Taken together, we find that the early (

) data are best explained by shock breakout in a massive shell of dense circumstellar material (0.02

) at large radii (

) that was ejected in eruptive pre-explosion mass-loss episodes. The late-time (

) light curve requires an additional energy source, which could be the radioactive decay of Ni-56.
Produção de H2 para células de combustível do tipo PEM via corrosão alcalina
Authors: Corcetti Melo Marina , Augustus de Melo Conrado , Neves da Silva Sabrina 
Published: December 2019

O H2 é um vetor energético que apresenta combustão limpa e é uma das soluções com grande potencial para enfrentamento futuro da escassez de recursos energéticos de base fóssil, para maior diversificação e segurança das matrizes energéticas dos países e, também, para minimização das emissões de gases de efeito estufa. O H2 não é uma fonte primária de energia, porém, pode ser produzido a partir de diversos recursos energéticos e processos químicos. O objetivo deste trabalho é avaliar a produção de H2 de elevada pureza a partir da reação do Al com as bases fortes NaOH e KOH. O Al utilizado é proveniente de latas de bebidas recicláveis. Estudou-se a influência da temperatura e concentração das soluções alcalinas sobre as taxas das reações. Verificou-se que, nas temperaturas estudas, a reação do Al com KOH tende a ser mais lenta do que com NaOH e quanto maior a concentração da solução, maior é a taxa de produção de H2, conforme esperado pela teoria. Foi verificado também que o método pode ser utilizado para produção de H2 in situ podendo ser utilizado em aplicações móveis e estacionárias.
« Je ne consentirai jamais à ce qu’ils m’appellent “évêque”. » Pastorat et épiscopat dans le méthodisme britannique de John Wesley à nos jours
Authors: Grosclaude Jérôme 
Published: December 2019

Dans cet article, Jérôme Grosclaude examine la place et la forme de l’autorité épiscopale dans le méthodisme britannique depuis sa naissance dans les années 1730 jusqu’à nos jours. Né d’une scission de facto d’avec l’Église d’Angleterre, qui a conservé le ministère à trois degrés, le méthodisme britannique ne l’adopta jamais, au contraire de son homologue aux États-Unis. Le méthodisme considère néanmoins depuis la fin du xviii	e siècle que l’episcopè, l’autorité épiscopale, est dûment exercée en son sein par les pasteurs ordonnés ou presbytres.
Why Do Some Nursing Students Find Their Science Courses Difficult?
Authors: Caon Martin , Treagust David 
Published: December 2019

ABSTRACT
A sample of undergraduate nursing students were allocated, according to their results in the first nursing science exam, to one of three groups: "successful," "unsuccessful," and "middle." The sample was surveyed about the perceived difficulty of their science course and reasons for the difficulty. The responses of the three groups were compared for significant differences using the KruskalWallis H statistic. The successful group was significantly different from the unsuccessful group in a number of responses to the questionnaire. Students in the unsuccessful group perceive that their science course is difficult, have a low opinion of their ability in science, and are not convinced of the relevance of their science course to nursing.
LADARWave Wavefront Measurement in Normal Eyes
Authors: Chalita Maria Regina , Finkenthal Josel , Xu Meng , Krueger Ronald R 
Published: December 2019

ABSTRACT
PURPOSE: We evaluated the correlation of Alcon LADARWave wavefront measurements with clinical refraction and corneal topography.
METHODS: In a retrospective, non-comparative case series, 60 eyes (30 patients) of healthy individuals evaluated by preoperative examination for refractive surgery were enrolled (manifest sphere, -11.00 to +4.50 D; manifest cylinder, 0 to -4.75 D; 45 eyes were myopic, 12 eyes were hyperopic, and 3 had mixed astigmatism). Correlation of manifest refraction, cycloplegic refraction, and topographic data with wavefront refraction and higher order aberration was assessed. Match percentage given by the wavefront was analyzed. This number represents how much of the wavefront refraction is due to sphere and cylinder (high percentage match) or is influenced by higher order aberration (low percentage match), in which case aberrometer refraction will not be close to phoropter refraction. Pearson's correlation coefficient was assessed for two continuous variables, adjusting for repeated measurements.
RESULTS: The median match percentage was 91%. Mean values for all higher order aberration components in a 7.0-mm pupil were: coma = 0.35 ± 0.29 µm, spherical aberrations = 0.36 ± 0.31 µm, and other terms of higher order aberrations = 0.31 ± 0.14 µm. Wavefront sphere, cylinder, and axis terms were highly correlated to manifest and cycloplegic measurements. The high match subgroup had a higher correlation coefficient than the low match subgroup for refraction. Topographic cylinder and axis were not strongly correlated to wavefront refraction, but manifest axis was significantly correlated to topographic axis.
CONCLUSION: In 60 normal eyes, the Alcon LADARWave wavefront measurement was highly correlated with refraction, but less well with corneal topography. [J Refract Surg 2004;20:132-138]
Wavefront-guided Surface Ablation With Prophylactic Use of Mitomycin C After a Buttonhole Laser in situ Keratomileusis Flap
Authors: Chalita Maria Regina , Roth Allen S , Krueger Ronald R 
Published: December 2019

ABSTRACT
PURPOSE: To describe the surgical outcome of a patient who had a previous buttonhole after laser in situ keratomileusis (LASIK) and 3 months later, had wavefront-guided photorefractive keratectomy (PRK) with topical mitomycin C 0.02%.
METHODS: A 38-year-old man underwent bilateral LASIK for correction of myopic astigmatism. A buttonhole in his right eye LASIK flap occurred, but the surgeon decided to proceed with ablation due to the small size of the buttonhole. After LASIK, the patient complained of monocular diplopia in his right eye with 20/30 best spectacle-corrected visual acuity. Wavefront analysis showed a large amount of higher order aberrations, especially coma. Slit-lamp examination revealed a moderate buttonhole scar. Three months after LASIK, the patient underwent wavefront-guided PRK with application of topical mitomycin C 0.02% on the stromal bed, for a duration of 2 minutes.
RESULTS: One month after wavefront-guided PRK, his uncorrected visual acuity was 20/25 in the right eye, with no symptoms. Best spectacle-corrected visual acuity in the right eye was 20/15 with +0.25 -0.50 x 110°. No haze or scar was seen on slit-lamp examination. Wavefront analysis showed a decrease in higher order aberrations, especially coma and spherical aberration.
CONCLUSIONS: Wavefront-guided PRK with prophylactic topical mitomycin C was effective in treating a patient with visual symptoms and loss of BSCVA after a LASIK flap buttonhole. No delayed epithelial healing, side effects or complications were noted due to mitomycin C. [J Refract Surg 2004;20:176-181]
Total and Corneal Optical Aberrations Induced by Laser in situ Keratomileusis for Hyperopia
Authors: Llorente Lourdes , Barbero Sergio , Merayo Jesus , Marcos Susana 
Published: December 2019

ABSTRACT
PURPOSE: To evaluate changes induced by standard laser in situ keratomileusis (LASIK) for hyperopia on total and corneal optical quality.
METHODS: Total and corneal aberrations were measured before and after standard hyperopic LASIK in 13 eyes (preoperative spherical equivalent refractive error +3.17 ± 1.10 D). The Chiron Technolas 217C laser with PlanoScan was used. Total aberrations (measured using laser ray tracing) and corneal aberrations (estimated from a videokeratoscope) were described using Zernike terms. Root-mean-square wavefront error for both total and corneal aberrations, and through-focus Strehl ratio for the point spread function of the whole eye were used to assess optical changes induced by surgery.
RESULTS: Third and higher order aberrations increased significantly after hyperopic LASIK (by a factor of 2.20 for total and 1.78 for corneal aberrations, for a 6.5-mm pupil). Spherical aberration changed to negative values (corneal average decreased by -0.85 ± 0.48 µm and total average by -0.70 ± 0.30 µm). Best Strehl ratio for the whole eye decreased by a factor of 1.84. Hyperopic LASIK induced larger changes than myopic LASIK, compared to an equivalent group of myopic eyes from a previous study. Induced corneal spherical aberration was six times larger after hyperopic LASIK, for a similar range of correction, and of opposite sign. As with myopic LASIK, changes in internal spherical aberration are of opposite sign to those induced on the corneal anterior surface.
CONCLUSIONS: Hyperopic LASIK induced significant amounts of aberrations. The largest increase occurred in spherical aberration, which showed a shift (toward negative values) of opposite sign; increase was greater than for myopic LASIK. [J Refract Surg 2004;20:203-216]
Prospective, Paired Comparison of Laser in situ Keratomileusis and Laser Epithelial Keratomileusis for Myopia Less Than -6.00 Diopters
Authors: Kaya Vedat , Oncel Banu , Sivrikaya Hakan , Yilmaz Omer Faruk 
Published: December 2019

ABSTRACT
PURPOSE: To compare visual and refractive results, contrast sensitivity, and tear stability after laser in situ keratomileusis (LASIK) in one eye and laser epithelial keratomileusis (LASEK) in the fellow eye for low myopia.
METHODS: Patients diagnosed with low myopia, with a maximum difference of 1 D between their two eyes, were randomly assigned to receive LASEK on one eye and LASIK on the other eye. A total of 64 eyes of 32 patients with a mean age of 26.83±5.33 years were included in the study. Preoperative myopia ranged from -1.00 to -6.00 D. Follow-up was 6 to 12 months. Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), Schirmer test results, tear break-up time, corneal asphericity, corneal uniformity index, predicted corneal acuity, and contrast sensitivity values were compared with preoperative values. A Wilcoxon test was used for statistical comparisons and a P-value less than .05 was considered significant.
RESULTS: At 6 months after surgery, there was no statistically significant difference in UCVA, BSCVA, spherical and cylindrical refractive error, Schirmer test, or tear break-up time between groups. Contrast sensitivity values in the LASIK eyes were lower in comparison to preoperative values, but there was no change in the LASEK group.
CONCLUSIONS: Based on 6-month results, LASEK for low myopia was safe and effective with predictable results, offered early refractive stability, and may be considered an alternative for LASIK. [J Refract Surg 2004;20:223-228]
Flap Quality in Single Versus Multiple Use of the Same Blade in the Flapmaker Microkeratome
Authors: Módis László , Langenbucher Achim , Behrens Ashley , Seitz Berthold 
Published: December 2019

ABSTRACT
PURPOSE: We evaluated experimentally the variability of cut thickness, flap diameter, and cut quality produced by the Flapmaker corneal microkeratome (IOLTech), with single and repeated use of the same cutting blade.
METHODS: Keratectomy was performed with twelve cutting heads (8.5-mm diameter, 160-µm cutting depth) on 47 corneas and with six cutting heads (8.0-mm diameter, 180-µm cutting depth) on 18 freshly enucleated swine eyes in a repeated manner. Ultrasonic pachymetry was determined at the initial, central, and final microkeratome pass zones, first before the flap was created and subsequently after the flap was reflected. Flap diameter was measured by planimetry. After the procedure stromal portions were submitted for scanning electron microscopy.
RESULTS: On the first blade use, mean central flap thickness was 145 ± 32 µm and mean vertical flap diameter was 8.4 ± 0.26 mm with the 8.5-mm blades. With the 8.0-mm blades, mean central flap thickness was 155 ± 23 µm and mean vertical flap diameter was 8.0 ± 0.27 mm. Scanning electron microscopy disclosed smooth cut surfaces when new blades were used, but with repeated blade use, increasingly prominent stromal bed folds were observed.
CONCLUSIONS: The evaluated blades produced reproducible flap size and thickness and good cut quality with single use, but after the first use, cut quality markedly deteriorated. Repeated use of Flapmaker cutting blades is not recommended. [J Refract Surg 2004;20:258-264]
Outcomes of Laser in situ Keratomileusis in a Refractive Surgery Fellowship Program
Authors: Bowers Patrick J , Zeldes Steven S , Price Marianne O , McManis Craig L , Price Francis W 
Published: December 2019

ABSTRACT
PURPOSE: The purpose of this study was to document the learning curve and evaluate the success of laser in situ keratomileusis (LASIK) performed by fellows in a Cornea/External Disease and Refractive fellowship program.
METHODS: Two surgeons performed LASIK within a fellowship training program between July 2000 and August 2001. A retrospective review was conducted to determine the visual outcomes and operative complications from this non-comparative case series of 755 consecutive eyes. All LASIK procedures were performed using a Bausch & Lomb Technolas 217A laser and the Bausch & Lomb Hansatome or the Automated Corneal Shaper microkeratome. All eyes were evaluated for operative complications. Visual acuity was reported with a minimum of 1 month follow-up.
RESULTS: Data analysis revealed that uncorrected visual acuity of 20/40 or better was attained in 99.4% of treated eyes, and 20/20 or better in 77.2%. With both eyes open, 100% of patients saw 20/30 or better, 94% saw 20/20 or better, 70% saw 20/15 or better, and 5.5% saw 20/10. Flap related complications occurred in 7 of 755 eyes (0.9%) and all were successfully treated. Forty-two eyes (5.6%) were lost to follow-up prior to the 1-month examination and were excluded from analysis of visual acuity.
CONCLUSIONS: Favorable operative and visual acuity 1-month results in 755 eyes after LASIK with the Bausch & Lomb Techno las 217A laser were in part due to a well organized system of education, patient examination, execution of surgery, and postoperative care. A team approach was essential. [J Refract Surg 2004;20:265-269]
Pupil Size in Refractive Surgery Candidates
Authors: Netto Marcelo V , Ambrósio Renato , Wilson Steven E 
Published: December 2019

ABSTRACT
PURPOSE: To assess pupil size measurements obtained under scotopic and mesopic conditions with the Procyon pupillometer and under photopic conditions with the Humphrey videokeratographer.
METHODS: The pupil sizes of 96 candidates for refractive surgery (192 eyes) were measured with the Procyon pupillometer PS2000 SA and the Humphrey Atlas 992 corneal topographer. Anisocoria and pupillary unrest were analyzed according to gender (two groups: 51 females and 45 males), age (five groups: 20 to 30 yr, 31 to 40 yr, 41 to 50 yr, 51 to 60 yr, older than 60 yr) and level of refraction (five groups: >-6.00 D SE, -6.00 to ?3.00 D SE, -3.00 to 0 D SE, 0 to +2.50 D SE, +2.50 to +5.00 D SE).
RESULTS: The median value of pupil diameter measured with the Procyon pupillometer at the scotopic (0.04 lux), mesopic-low (0.4 lux), and mesopic-high (4 lux) levels of illumination were 6.54 ? 0.88 mm; 5.62 ? 0.95 mm, and 4.09 ? 0.76 mm, respectively. The median pupil size with the Humphrey topographer was 3.65 ? 0.62 mm. Pupillary unrest was highest at the mesopic-high level of illumination, with a median value of 0.31 ? 0.34 mm. Median pupil size measured with both instruments at all light levels dropped significantly after the fifth decade of life (P<.05, ANOVA).
CONCLUSIONS: The Procyon pupillometer and Humphrey videokeratographer revealed an inverse correlation between the pupil size and the age, but no relationship with gender or level of refraction. The Procyon pupillometer provides an objective method for measuring pupil size at controlled light levels with a permanent printed record. [J Refract Surg 2004;20:337-342]
Five-year Follow-up of Laser in situ Keratomileusis for Hyperopia Using the Technolas Keracor 117C Excimer Laser
Authors: Esquenazi Salomon 
Published: December 2019

ABSTRACT
PURPOSE: To evaluate safety, predictability, efficiency, and long-term stability of laser in situ keratomileusis (LASIK) for spherical hyperopia.
METHODS: This study was a retrospective 5-year analysis of 67 patients (125 eyes) who had LASIK for spherical hyperopia; preoperative mean manifest spherical equivalent refraction was +3.84 ? 1.13 D (range +1.00 to +6.50 D) and mean astigmatism was 0.37 ? 0.27 D (range 0 to 1.00 D). Preoperative spherical equivalent refraction for the low hyperopia group was +1.00 to +2.75 D; medium hyperopia group, +3.00 to +4.25 D, and high hyperopia group, +4.50 to +6.50 D. All surgeries were performed using the scanning Chiron Technolas Keracor 11 7C excimer laser. Uncorrected and best spectacle-corrected visual acuity, predictability, long-term stability of refraction, and complications were analyzed.
RESULTS: At 5 years after hyperopic LASIK, mean spherical equivalent refraction for the low hyperopia group was +0.48D ? 0.79 D; medium hyperopia group, +1.52 ? 1.45 D; high hyperopia group C, +3.39 ? 1.98 D. The percentage of eyes with a spherical equivalent refraction within ?0.50 D of emmetropia for the low hyperopia group was 63% (37 eyes); medium hyperopia group, 42% (20 eyes); high hyperopia group, 22% (4 eyes). Eyes with chronic dry eye symptoms had a mean difference in spherical equivalent refraction from target refraction of +1.43 D compared with +0.84 D for eyes without dry eye symptoms. Five eyes (4%) lost 2 lines of BSCVA at 5 years.
CONCLUSION: LASIK was safe, effective, and stable for primary hyperopia between +1.00 and +3.00 D. Higher amounts of hyperopia had poor long-term stability, especially eyes with more than +4.25 D. Chronic dry eye symptoms were associated with regression over time. [J Refract Surg 2004; 20:356-363]