bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation of the UV Spectrum of Molecular Hydrogen in the Sun
Authors: Jaeggli S. A. , Judge P. G. , Daw A. N. 
Published: March 2018

Abstract
Ultraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in particular regions, selectively excited by a bright UV transition region and chromospheric lines. We test the conditions under which H2 emission can originate by studying non-LTE models, sampling a broad range of temperature stratifications and radiation conditions. Stratification plays the dominant role in determining the population densities of H2, which forms in greatest abundance near the continuum photosphere. However, opacity due to the photoionization of Si and other neutrals determines the depth to which UV radiation can penetrate to excite the H2. Thus the majority of H2 emission forms in a narrow region, at about 650 km in standard one-dimensional (1D) models of the quiet Sun, near the τ = 1 opacity surface for the exciting UV radiation, generally coming from above. When irradiated from above using observed intensities of bright UV emission lines, detailed non-LTE calculations show that the spectrum of H2 seen in the quiet-Sun Solar Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can be satisfactorily reproduced in 1D stratified atmospheres, without including three-dimensional or time-dependent thermal structures. A detailed comparison to observations from 1205 to 1550 Å is presented, and the success of this 1D approach to modeling solar UV H2 emission is illustrated by the identification of previously unidentified lines and upper levels in HRTS spectra.
Extinction Maps and Dust-to-gas Ratios in Nearby Galaxies with LEGUS
Authors: Kahre L. , Walterbos R. A. , Kim H. , Thilker D. , Calzetti D. , Lee J. C. , Sabbi E. , Ubeda L. , Aloisi A. , Cignoni M. , Cook D. O. , Dale D. A. , Elmegreen B. G. , Elmegreen D. M. , Fumagalli M. , Gallagher J. S. , Gouliermis D. A. , Grasha K. , Grebel E. K , Hunter D. A. , Sacchi E. , Smith L. J. , Tosi M. , Adamo A. , Andrews J. E. , Ashworth G. , Bright S. N. , Brown T. M. , Chandar R. , Christian C. , de Mink S. E. , Dobbs C. , Evans A. S. , Herrero A. , Johnson K. E. , Kennicutt R. C. , Krumholz M. R. , Messa M. , Nair P. , Nota A. , Pellerin A. , Ryon J. E. , Schaerer D. , Shabani F. , Van Dyk S. D. , Whitmore B. C. , Wofford A. 
Published: March 2018

Abstract
We present a study of the dust-to-gas ratios in five nearby galaxies: NGC 628 (M74), NGC 6503, NGC 7793, UGC 5139 (Holmberg I), and UGC 4305 (Holmberg II). Using Hubble Space Telescope broadband WFC3/UVIS UV and optical images from the Treasury program Legacy ExtraGalactic UV Survey (LEGUS) combined with archival HST/Advanced Camera for Surveys data, we correct thousands of individual stars for extinction across these five galaxies using an isochrone-matching (reddening-free Q) method. We generate extinction maps for each galaxy from the individual stellar extinctions using both adaptive and fixed resolution techniques and correlate these maps with neutral H i and CO gas maps from the literature, including the H i Nearby Galaxy Survey and the HERA CO-Line Extragalactic Survey. We calculate dust-to-gas ratios and investigate variations in the dust-to-gas ratio with galaxy metallicity. We find a power-law relationship between dust-to-gas ratio and metallicity, consistent with other studies of dust-to-gas ratio compared to metallicity. We find a change in the relation when H2 is not included. This implies that underestimation of

N

H

2

in low-metallicity dwarfs from a too-low CO-to-H2 conversion factor X
CO could have produced too low a slope in the derived relationship between dust-to-gas ratio and metallicity. We also compare our extinctions to those derived from fitting the spectral energy distribution (SED) using the Bayesian Extinction and Stellar Tool for NGC 7793 and find systematically lower extinctions from SED fitting as compared to isochrone matching.
Empirical Modeling of the Redshift Evolution of the
[
N
II
]
/Hα Ratio for Galaxy Redshift Surveys
Authors: Faisst Andreas L. , Masters Daniel , Wang Yun , Merson Alexander , Capak Peter , Malhotra Sangeeta , Rhoads James E. 
Published: March 2018

Abstract
We present an empirical parameterization of the [N ii]/Hα flux ratio as a function of stellar mass and redshift valid at 0 < z < 2.7 and

8.5
<
log
(
M

/

M

⊙

)
<
11.0

. This description can (i) easily be applied to simulations for modeling [N ii]λ6584 line emission, (ii) deblend [N ii] and Hα in current low-resolution grism and narrow-band observations to derive intrinsic Hα fluxes, and (iii) reliably forecast the number counts of Hα emission-line galaxies for future surveys, such as those planned for Euclid and the Wide Field Infrared Survey Telescope (WFIRST). Our model combines the evolution of the locus on the Baldwin, Phillips & Terlevich (BPT) diagram measured in spectroscopic data out to z ∼ 2.5 with the strong dependence of [N ii]/Hα on stellar mass and [O iii]/Hβ observed in local galaxy samples. We find large variations in the [N ii]/Hα flux ratio at a fixed redshift due to its dependency on stellar mass; hence, the assumption of a constant [N ii] flux contamination fraction can lead to a significant under- or overestimate of Hα luminosities. Specifically, measurements of the intrinsic Hα luminosity function derived from current low-resolution grism spectroscopy assuming a constant 29% contamination of [N ii] can be overestimated by factors of ∼8 at

log
(
L
)
>
43.0

for galaxies at redshifts z ∼ 1.5. This has implications for the prediction of Hα emitters for Euclid and WFIRST. We also study the impact of blended Hα and [N ii] on the accuracy of measured spectroscopic redshifts.
I documenti settecenteschi come strumenti per lo studio degli scavi ercolanesi
Authors: Allroggen-Bedel Agnes 
Published: March 2018

En lisant les différents rapports – partiellement publiés – des fouilles conduites à Herculanum au XVIIIe siècle, on cherche à savoir dans quelle partie de la cité et dans quel édifice les ouvriers étaient en train de travailler. Il n’est pas facile d’identifier les structures et objets mentionnés dans les rapports, et décrits de manière assez approximative, et même parfois impossible… En dépit de cette difficulté, les documents du XVIIIe siècle offrent des informations précieuses pour l’étude de l’histoire des fouilles, pour la reconstitution des contextes picturaux et pour la recontextualisation des objets provenant des cités vésuviennes. Afin d’illustrer les problèmes, les méthodes, les possibilités et les limites de telles études, seront présentés ici quelques exemples caractéristiques.
L’inspiration et l’imprudence : poésie de l'anticomanie dans la critique d'art du second xixe siècle
Authors: Le Pape Yannick 
Published: March 2018

Quand il s’agissait de commenter la peinture qui, du milieu à la fin du xixe siècle, prenait l’Antiquité comme thème, il n’était pas rare que les journalistes ou les historiens d’art convoquent l’autorité de la poésie. On réclamait alors des peintres une habileté comparable à celle d’Eschyle ou de Théocrite et on les félicitait lorsqu’ils parvenaient à atteindre une profonde « distinction poétique » (Paul de Saint-Victor). Les critiques ne furent cependant pas univoques sur cette exigence : indispensable pour les uns, elle restait pour les autres à manier avec parcimonie tant elle pouvait être le signe d’une sensiblerie inadaptée à la peinture d’histoire. La question était aussi de savoir si l’Antiquité pouvait conserver ce monopole de la grâce en plein essor du naturalisme et de cette poésie du réel que l’opinion découvrait. On comprend alors combien la peinture anticomane, loin d’être anachronique, s’inscrivait bel et bien dans une réflexion générale sur l’évolution des arts et la modernité.
La non-vocation d’André Schwarz-Bart
Authors: Kaufmann Francine 
Published: March 2018

L’attribution du prix Goncourt 1959 au Dernier des Justes, œuvre d’un jeune inconnu dont c’était le premier roman, suscita un intérêt inhabituel pour la personnalité de l’auteur : André Schwarz-Bart. La presse se nourrit d’interviews, s’étonnant qu’un ouvrier autodidacte, fils d’immigrants parlant yiddish, contraint par la guerre à quitter les bancs de l’école à onze ans, produise spontanément un chef d’œuvre sans avoir été formé à la littérature. Le « cas Schwarz-Bart » défraya la chronique. Cette étude veut mettre en lumière la lente maturation d’un talent littéraire chez un homme que rien ne destinait à être écrivain et qui proclamait qu’il n’avait pas répondu à une vocation irrésistible, mais à une nécessité : exprimer, sous peine d’étouffer, la douleur indicible provoquée par l’extermination de ses parents et d’une grande partie de son peuple. Nous montrerons que « l’ouvrier » Schwarz-Bart avait entamé des études et fréquenté assidûment les milieux étudiants, plus encore après son désenchantement du communisme à partir de l’Affaire Slansky (1951). Enfin, nous étudierons les traces de la biographie de l’écrivain dans un roman qui se voulait œuvre de fiction et témoignage pour un peuple tout entier.
Different Selected Mechanisms Attenuated the Inhibitory Interaction of KIR2DL1 with C2+ HLA-C in Two Indigenous Human Populations in Southern Africa
Authors: Nemat-Gorgani Neda , Hilton Hugo G. , Henn Brenna M. , Lin Meng , Gignoux Christopher R. , Myrick Justin W. , Werely Cedric J. , Granka Julie M. , Möller Marlo , Hoal Eileen G. , Yawata Makoto , Yawata Nobuyo , Boelen Lies , Asquith Becca , Parham Peter , Norman Paul J. 
Published: March 2018

Abstract
The functions of human NK cells in defense against pathogens and placental development during reproduction are modulated by interactions of killer cell Ig-like receptors (KIRs) with HLA-A, -B and -C class I ligands. Both receptors and ligands are highly polymorphic and exhibit extensive differences between human populations. Indigenous to southern Africa are the KhoeSan, the most ancient group of modern human populations, who have highest genomic diversity worldwide. We studied two KhoeSan populations, the Nama pastoralists and the ≠Khomani San hunter-gatherers. Comprehensive next-generation sequence analysis of HLA-A, -B, and -C and all KIR genes identified 248 different KIR and 137 HLA class I, which assort into ∼200 haplotypes for each gene family. All 74 Nama and 78 ≠Khomani San studied have different genotypes. Numerous novel KIR alleles were identified, including three arising by intergenic recombination. On average, KhoeSan individuals have seven to eight pairs of interacting KIR and HLA class I ligands, the highest diversity and divergence of polymorphic NK cell receptors and ligands observed to date. In this context of high genetic diversity, both the Nama and the ≠Khomani San have an unusually conserved, centromeric KIR haplotype that has arisen to high frequency and is different in the two KhoeSan populations. Distinguishing these haplotypes are independent mutations in KIR2DL1, which both prevent KIR2DL1 from functioning as an inhibitory receptor for C2+ HLA-C. The relatively high frequency of C2+ HLA-C in the Nama and the ≠Khomani San appears to have led to natural selection against strong inhibitory C2-specific KIR.
Evaluation of Flexural Strength of Polymethyl Methacrylate modified with Silver Colloidal Nanoparticles subjected to Two Different Curing Cycles: An in vitro Study
Authors: Ranganath LM , Gaikwad Ajay , Jain Saket K , Pal Kapil S 
Published: March 2018

ABSTRACT
Aim
Silver colloidal nanoparticles have been incorporated into acrylic resins to induce antimicrobial properties. However, as additives, they can influence the mechanical properties of the final product. Mechanical properties are also dependent on different curing cycles. The aim of this study was to evaluate flexural strength of a denture base resin incorporated with different concentrations of silver colloidal nanoparticles subjected to two different curing cycles.

Materials and methods
Lucitone 199 denture base resin was used into which silver colloidal nanoparticles were incorporated at 0.5 and 5% by polymer mass. Specimens devoid of nanoparticles were used as controls. A total of 60 specimens were fabricated and divided into two groups. Each group was divided into three subgroups consisting of 10 specimens each. The specimens were fabricated according to American Dental Association (ADA) specification No. 12 and tested for flexural strength using universal testing machine.

Results
Silver colloidal nanoparticle incorporation at 0.5% concentration increased the mean flexural strength in both curing cycles by 7.5 and 4.4%, respectively, when compared with the control group.

Conclusion
The study suggested that the mean flexural strength value of 0.5% silver colloidal nanoparticles in denture base resin was above the value of the control group both in short and long curing cycles, which makes it clinically suitable as a denture base material. However, at 5% concentration, the statistically significant amount of decrease in flexural strength compared with the value of control group both in short and long curing cycles gives it a questionable prognosis.

Clinical significance
The specimens incorporated with the antimicrobial agent 0.5% silver colloidal nanoparticles and processed by long curing cycles showed significant increase in its flexural strength compared with the control group, which makes it clinically suitable as a denture base material.

How to cite this article
Munikamaiah RL, Jain SK, Pal KS, Gaikwad A. Evaluation of Flexural Strength of Polymethyl Methacrylate modified with Silver Colloidal Nanoparticles subjected to Two Different Curing Cycles: An in vitro Study. J Contemp Dent Pract 2018;19(3):262-268.
Comparison between Fluoride and Nano-hydroxyapatite in Remineralizing Initial Enamel Lesion: An in vitro Study
Authors: Daas Issa , Badr Sherine , Osman Essam 
Published: March 2018

ABSTRACT
Aim
The aim of this study was to compare the effectiveness of nano-hydroxyapatite (nano-HAP) paste and fluoride varnish in remineralizing initial enamel lesion in young permanent teeth and their ability to resist secondary caries under dynamic pH cycling quantitatively and qualitatively.

Materials and methods
Initial caries-like lesions were artificially developed on 45 specimens. Specimens were divided into three groups: (1) Control (without treatment), (2) fluoride varnish (3M ESPE), and (3) nano-HAP paste (Desensibilize Nano P). The nano-HAP paste was applied twice separated by one pH cycle, and the varnish was applied only once followed by 7 days of pH cycling. All specimens were examined using DIAGNOdent® pen (KaVo, Germany), and a representative specimen was randomly selected from each group for qualitative evaluation using scanning electron microscope (SEM) at four stages: Baseline, after lesion formation, immediately after remineralization, and after pH cycling. Data were statistically analyzed with Statistical Package for the Social Sciences (SPSS), version 20.

Results
The degree of demineralization was significantly elevated in control group; however, no significant difference was found between fluoride varnish group and nano-HAP paste group (p < 0.001).

Conclusion
Nano-HAP paste showed promising long-term protective effect in terms of surface depositions and maintaining a smooth surface compared with fluoride varnish.

Clinical significance
Based on the findings of this study, nano-HAP paste might be recommended as alternative remineralizing agent with lower fluoride concentration than fluoride varnish that could be beneficial for children, pregnant females, and those who are at high risk of dental fluorosis.

How to cite this article
Daas I, Badr S, Osman E. Comparison between Fluoride and Nano-hydroxyapatite in Remineralizing Initial Enamel Lesion: An in vitro Study. J Contemp Dent Pract 2018;19(3):306-312.
Utilizing the GentleWave® System for Debridement of Undetected Apical Anatomy
Authors: Ford Michael W 
Published: March 2018

ABSTRACTAim and backgroundDebriding and disinfecting complex anatomies within the root canal system pose a major challenge during root canal therapy. Even with current chemomechanical techniques, debris and bacterial remnants are commonly left behind, which are generally believed to increase the risk of endodontic failure. This case details the use of a new technique to debride complex apical anatomy in a maxillary molar.Case reportA 48-year-old female presented to the clinic with a chief complaint of increasing pain in her tooth. Clinical examination of the right first maxillary molar (#3) revealed moderate sensitivity to percussion and mild sensitivity to palpation. A pulpal diagnosis of symptomatic irreversible pulpitis and a periapical diagnosis of symptomatic apical periodontitis were made. Mechanical instrumentation was performed using rotary file size #25/.04 for the mesiobuccal and distobuccal canals and size #25/.06 for the palatal canal to create a fluid path and enable obturation of the root canal system following the GentleWave®Procedure. The GentleWave Procedure was completed using Multisonic Ultracleaning™ for complete debridement and disinfection of the root canal system. The tooth was obturated using a warm vertical continuous wave obturation technique. Postoperative radiographs revealed complex anatomy within the apical third that was undetected both during pre-operative radiography and mechanical instrumentation. The palatal canal exhibited a complex apical delta with multiple points of exit, and the mesiobuccal canal revealed an undetected lateral canal within the apical third that had a separate and distinct egress.Conclusion and clinical significanceIt is important for the clinician to debride and disinfect complex anatomy within the root canal system to reduce the risk of endodontic failure. This case report highlights the clinical significance of utilizing the GentleWave Procedure for detecting complex apical anatomy during endodontic therapy.How to cite this articleFord MW. Utilizing the GentleWave®System for Debridement of Undetected Apical Anatomy. J Contemp Dent Pract 2018;19(3):345-351.
Report of a large depletion in the ozone layer over southern Brazil and Uruguay by using multi-instrumental data
Authors: Bresciani Caroline , Bittencourt Gabriela Dornelles , Bageston José Valentin , Pinheiro Damaris Kirsch , Schuch Nelson Jorge , Bencherif Hassan , Leme Neusa Paes , Peres Lucas Vaz 
Published: March 2018

Abstract. Ozone is one of the chemical compounds that form part of the atmosphere. It
plays a key role in the stratosphere where the “ozone layer” is located and
absorbs large amounts of ultraviolet radiation. However, during austral
spring (August–November), there is a massive destruction of the ozone layer,
which is known as the “Antarctic ozone hole”. This phenomenon decreases
ozone concentration in that region, which may affect other regions in
addition to the polar one. This anomaly may also reach mid-latitudes; hence,
it is called the “secondary effect of the Antarctic ozone hole”. Therefore,
this study aims to identify the passage of an ozone secondary effect (OSE)
event in the region of the city of Santa Maria – RS (29.68∘ S,
53.80∘ W) by means of a multi-instrumental analysis using the
satellites TIMED/SABER, AURA/MLS, and OMI-ERS. Measurements were made in
São Martinho da Serra/RS – Brazil (29.53∘ S, 53.85∘ W)
using a sounding balloon and a Brewer Spectrophotometer. In addition, the
present study aims to describe and analyse the influence that this
stratospheric ozone reduction has on temperatures presented by these
instruments, including data collected through the radio occultation
technique. The event was first identified by the AURA/MLS satellite on
19 October 2016 over Uruguay. This reduction in ozone concentration was found
by comparing the climatology for the years 1996–1998 for the state of Rio
Grande do Sul, which is close to Uruguay. This event was already observed in
Santa Maria/RS-Brazil on 20 October 2016 as presented by the OMI-ERS
satellite and the Brewer Spectrophotometer. Moreover, a significant decrease
was reported by the TIMED/SABER satellite in Uruguay. On 21 October, the poor
ozone air mass was still over the region of interest, according to the
OMI-ERS satellite, data from the sounding balloon launched in Santa
Maria/RS-Brazil, and measurements made by the AURA/MLS satellite.
Furthermore, the influence of ozone on the stratosphere temperature was
observed during this period. Despite a continuous decrease detected in
height, the temperature should have followed an increasing pattern in the
stratospheric layer. Finally, the TIMED/SABER and OMI-ERS satellites showed
that on 23 October, the air mass with low ozone concentration was moving
away, and its layer, as well as the temperature, in the stratosphere was
re-established. Keywords. Atmospheric composition and structure (middle atmosphere – composition and chemistry; instruments and techniques)
Ages and transit times as important diagnostics of model performance for predicting carbon dynamics in terrestrial vegetation models
Authors: Ceballos-Núñez Verónika , Richardson Andrew D. , Sierra Carlos A. 
Published: March 2018

Abstract. The global carbon cycle is strongly controlled by the source/sink strength of vegetation as well as the capacity of terrestrial ecosystems to retain this carbon. These dynamics, as well as processes such as the mixing of old and newly fixed carbon, have been studied using ecosystem models, but different assumptions regarding the carbon allocation strategies and other model structures may result in highly divergent model predictions. We assessed the influence of three different carbon allocation schemes on the C cycling in vegetation. First, we described each model with a set of ordinary differential equations. Second, we used published measurements of ecosystem C compartments from the Harvard Forest Environmental Measurement Site to find suitable parameters for the different model structures. And third, we calculated C stocks, release fluxes, radiocarbon values (based on the bomb spike), ages, and transit times. We obtained model simulations in accordance with the available data, but the time series of C in foliage and wood need to be complemented with other ecosystem compartments in order to reduce the high parameter collinearity that we observed, and reduce model equifinality. Although the simulated C stocks in ecosystem compartments were similar, the different model structures resulted in very different predictions of age and transit time distributions. In particular, the inclusion of two storage compartments resulted in the prediction of a system mean age that was 12–20 years older than in the models with one or no storage compartments. The age of carbon in the wood compartment of this model was also distributed towards older ages, whereas fast cycling compartments had an age distribution that did not exceed 5 years. As expected, models with C distributed towards older ages also had longer transit times. These results suggest that ages and transit times, which can be indirectly measured using isotope tracers, serve as important diagnostics of model structure and could largely help to reduce uncertainties in model predictions. Furthermore, by considering age and transit times of C in vegetation compartments as distributions, not only their mean values, we obtain additional insights into the temporal dynamics of carbon use, storage, and allocation to plant parts, which not only depends on the rate at which this C is transferred in and out of the compartments but also on the stochastic nature of the process itself.