bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of the sonic properties of a Nigerian quartz for ultrasonic transducer
Authors: Nwadike Uchechukwu I. , Agwu Kenneth K. , Eze Charles U. , Kani Duke , Agu Gregory , Enwereuzo Emmanuel , Obika Mike , Umoh Effiong , Ufomba Emmanuel 
Published: March 2018

BACKGROUND: There is abundant quartz deposit in Nigeria which has been used for export and building purposes. However, its electrical and piezoelectric properties have not been studied. Thus, whether it can be used as raw material for the indigenous electric industries is unknown to date. OBJECTIVE: This study aims to characterize the piezoelectric properties of smoky quartz for ultrasonic transducer and determine its sonic properties. METHOD: In the research approach, the raw quartz was cut into six crystals of rectangular shape using a universal cutter. The crystals were purified with a 100 ml hydrofluoric and hydrochloric acid solution under a temperature of 250°C in a furnace. The sizes, weights, and capacitance of crystals were determined using the standard measuring instruments. The resonance method was used for the determination of the frequency of minimum and maximum impedance of the crystals. The piezoelectric constants of the crystals were derived using the standard formula for determination of piezoelectric constants. RESULTS: The results show that the sonic properties represented by the piezoelectric charge constant (d31) and the piezoelectric voltage constant (g31) values are 2.52 (±1.075) ×10-8 c/ m2 and 1030.6114 ± 250.89 v/ m2 respectively. CONCLUSION: The present study has characterized Nigerian quartz for its piezoelectric properties and found that it was suitable for use in the construction of ultrasonic transducers.
Denoising images of dual energy X-ray absorptiometry using non-local means filters
Authors: Al-antari Mugahed A. , Al-masni Mohammed A. , Metwally Mohamed K. , Hussain Dildar , Park Se-Je , Shin Jeong-Sik , Han Seung-Moo , Kim Tae-Seong 
Published: March 2018

BACKGROUND: In general, the image quality of high and low energy images of dual energy X-ray absorptiometry (DXA) suffers from noise due to the use of a small amount of X-rays. Denoising of DXA images could be a key process to improve a bone mineral density map, which is derived from a pair of high and low energy images. This could further improve the accuracy of diagnosis of bone fractures and osteoporosis. OBJECTIVE: This study aims to develop and test a new technology to improve the quality, remove the noise, and preserve the edges and fine details of real DXA images. METHODS: In this study, a denoising technique for high and low energy DXA images using a non-local mean filter (NLM) was presented. The source and detector noises of a DXA system were modeled for both high and low DXA images. Then, the optimized parameters of the NLM filter were derived utilizing the experimental data from CIRS-BFP phantoms. After that, the optimized NLM was tested and verified using the DXA images of the phantoms and real human spine and femur. RESULTS: Quantitative evaluation of the results showed average 24.22% and 34.43% improvement of the signal-to-noise ratio for real high and low spine images, respectively, while the improvements were about 15.26% and 13.55% for the high and low images of the femur. The qualitative visual observations of both phantom and real structures also showed significantly improved quality and reduced noise while preserving the edges in both high and low energy images. Our results demonstrate that the proposed NLM outperforms the conventional method using an anisotropic diffusion filter (ADF) and median techniques for all phantom and real human DXA images. CONCLUSIONS: Our work suggests that denoising via NLM could be a key preprocessing method for clinical DXA imaging.
Projection decomposition algorithm for dual-energy computed tomography via deep neural network
Authors: Xu Yifu , Yan Bin , Chen Jian , Zeng Lei , Li Lei 
Published: March 2018

BACKGROUND: Dual-energy computed tomography (DECT) has been widely used to improve identification of substances from different spectral information. Decomposition of the mixed test samples into two materials relies on a well-calibrated material decomposition function. OBJECTIVE: This work aims to establish and validate a data-driven algorithm for estimation of the decomposition function. METHODS: A deep neural network (DNN) consisting of two sub-nets is proposed to solve the projection decomposition problem. The compressing sub-net, substantially a stack auto-encoder (SAE), learns a compact representation of energy spectrum. The decomposing sub-net with a two-layer structure fits the nonlinear transform between energy projection and basic material thickness. RESULTS: The proposed DNN not only delivers image with lower standard deviation and higher quality in both simulated and real data, and also yields the best performance in cases mixed with photon noise. Moreover, DNN costs only 0.4 s to generate a decomposition solution of 360 × 512 size scale, which is about 200 times faster than the competing algorithms. CONCLUSIONS: The DNN model is applicable to the decomposition tasks with different dual energies. Experimental results demonstrated the strong function fitting ability of DNN. Thus, the Deep learning paradigm provides a promising approach to solve the nonlinear problem in DECT.
The K2 M67 Study: A Curiously Young Star in an Eclipsing Binary in an Old Open Cluster*
Authors: Sandquist Eric L. , Mathieu Robert D. , Quinn Samuel N. , Pollack Maxwell L. , Latham David W. , Brown Timothy M. , Esselstein Rebecca , Aigrain Suzanne , Parviainen Hannu , Vanderburg Andrew , Stello Dennis , Somers Garrett , Pinsonneault Marc H. , Tayar Jamie , Orosz Jerome A. , Bedin Luigi R. , Libralato Mattia , Malavolta Luca , Nardiello Domenico 
Published: March 2018

Abstract
We present an analysis of a slightly eccentric (e = 0.05), partially eclipsing, long-period (P = 69.73 days) main-sequence binary system (WOCS 12009, Sanders 1247) in the benchmark old open cluster M67. Using Kepler

K2
and ground-based photometry, along with a large set of new and reanalyzed spectra, we derived highly precise masses (1.111 ± 0.015 and 0.748 ± 0.005 M
⊙) and radii (1.071 ± 0.008 ± 0.003 and 0.713 ± 0.019 ± 0.026 R
⊙, with statistical and systematic error estimates) for the stars. The radius of the secondary star is in agreement with theory. The primary, however, is approximately 15% smaller than reasonable isochrones for the cluster predict. Our best explanation is that the primary star was produced from the merger of two stars, as this can also account for the nondetection of photospheric lithium and its higher temperature relative to other cluster main-sequence stars at the same V magnitude. To understand the dynamical characteristics (low measured rotational line broadening of the primary star and low eccentricity of the current binary orbit), we believe that the most probable (but not the only) explanation is the tidal evolution of a close binary within a primordial triple system (possibly after a period of Kozai–Lidov oscillations), leading to merger approximately 1 Gyr ago. This star appears to be a future blue straggler that is being revealed as the cluster ages and the most massive main-sequence stars die out.
H− Opacity and Water Dissociation in the Dayside Atmosphere of the Very Hot Gas Giant WASP-18b
Authors: Arcangeli Jacob , Désert Jean-Michel , Line Michael R. , Bean Jacob L. , Parmentier Vivien , Stevenson Kevin B. , Kreidberg Laura , Fortney Jonathan J. , Mansfield Megan , Showman Adam P. 
Published: March 2018

Abstract
We present one of the most precise emission spectra of an exoplanet observed so far. We combine five secondary eclipses of the hot Jupiter WASP-18b (T
day ∼ 2900 K) that we secured between 1.1 and 1.7 μm with the Wide Field Camera 3 instrument on board the Hubble Space Telescope. Our extracted spectrum (S/N = 50, R ∼ 40) does not exhibit clearly identifiable molecular features but is poorly matched by a blackbody spectrum. We complement this data with previously published Spitzer/Infrared Array Camera observations of this target and interpret the combined spectrum by computing a grid of self-consistent, 1D forward models, varying the composition and energy budget. At these high temperatures, we find there are important contributions to the overall opacity from H− ions, as well as the removal of major molecules by thermal dissociation (including water), and thermal ionization of metals. These effects were omitted in previous spectral retrievals for very hot gas giants, and we argue that they must be included to properly interpret the spectra of these objects. We infer a new metallicity and C/O ratio for WASP-18b, and find them well constrained to be solar ([M/H] = −0.01 ± 0.35, C/O < 0.85 at 3σ confidence level), unlike previous work but in line with expectations for giant planets. The best-fitting self-consistent temperature–pressure profiles are inverted, resulting in an emission feature at 4.5 μm seen in the Spitzer photometry. These results further strengthen the evidence that the family of very hot gas giant exoplanets commonly exhibit thermal inversions.
Magnetic Reconnection May Control the Ion-scale Spectral Break of Solar Wind Turbulence
Authors: Vech Daniel , Mallet Alfred , Klein Kristopher G. , Kasper Justin C. 
Published: March 2018

Abstract
The power spectral density of magnetic fluctuations in the solar wind exhibits several power-law-like frequency ranges with a well-defined break between approximately 0.1 and 1 Hz in the spacecraft frame. The exact dependence of this break scale on solar wind parameters has been extensively studied but is not yet fully understood. Recent studies have suggested that reconnection may induce a break in the spectrum at a “disruption scale”

, which may be larger than the fundamental ion kinetic scales, producing an unusually steep spectrum just below the break. We present a statistical investigation of the dependence of the break scale on the proton gyroradius ρ

i
, ion inertial length d

i
, ion sound radius ρ

s
, proton–cyclotron resonance scale ρ

c
, and disruption scale

as a function of

. We find that the steepest spectral indices of the dissipation range occur when β

e
is in the range of 0.1–1 and the break scale is only slightly larger than the ion sound scale (a situation occurring 41% of the time at 1 au), in qualitative agreement with the reconnection model. In this range, the break scale shows a remarkably good correlation with

. Our findings suggest that, at least at low β

e
, reconnection may play an important role in the development of the dissipation range turbulent cascade and cause unusually steep (steeper than −3) spectral indices.
Asymptomatic Coronary Artery Calcifications in Men with Systemic Lupus Erythematosus
Authors: Romero-Díaz Juanita , Acosta-Hernández Roberto Iván , Criales-Vera Sergio , Kimura-Hayama Erick , Domínguez-Quintana Maricruz , Morán-Contla Rocío , Núñez-Alvarez Carlos , Lara-Reyes Pilar , Aguilar-Salinas Carlos , Sánchez-Guerrero Jorge 
Published: March 2018

Objective.To determine whether the prevalence and extent of asymptomatic coronary artery atherosclerosis are increased in men with systemic lupus erythematosus (SLE) compared with age- and sex-matched controls, and to define the associated risk factors.Methods.Ninety-five patients with SLE (mean ± SD age, 34.7 ± 10.1 yrs) and 100 control subjects (age 34.8 ± 9.7 yrs) with no history of coronary artery disease were screened for coronary artery calcification using multidetector computed tomography. The extent of calcification was measured using the Agatston score. The frequency of risk factors for calcification was compared between patients and controls, and the relationship between clinical and immunological characteristics and the presence of coronary artery calcification was investigated.Results.Coronary artery calcification was more frequent in patients than controls [18% vs 7%, respectively (OR 2.89, 95% CI 1.07–8.65)]. These factors were independently associated with the presence of calcifications: age (OR 1.12, 95% CI 1.04–1.20), SLE diagnosis (OR 3.38, 95% CI 1.07–10.64), diabetes mellitus (OR 6.88, 95% CI 1.50–31.62), Framingham risk score (OR 1.12, 95% CI 1.00–1.23), and glomerular filtration rate (OR 0.98, 95% CI 0.96–1.00). Among patients with SLE, coronary artery calcifications were observed starting at age 32 years, within 2.3 years of diagnosis. Increasing age (OR 1.18, 95% CI 1.06–1.31), Systemic Lupus International Collaborating Clinics score (OR 2.85, 95% CI 1.21–6.73), and cumulative dose of prednisone (OR 1.04, 95% CI 1.01–1.08) were independent risk factors.Conclusion.Men with SLE are at an increased risk of coronary artery calcifications than age- and sex-matched controls. Among patients with SLE, the increased risk is associated to older age, increasing chronic damage, and cumulative dose of corticosteroids.
Hydroxychloroquine Inhibits the Differentiation of Th17 Cells in Systemic Lupus Erythematosus
Authors: Yang Ji , Yang Xue , Yang Jie , Li Ming 
Published: March 2018

Objective.Hydroxychloroquine (HCQ) is a commonly used medicine for the treatment of systemic lupus erythematosus (SLE), and Th17 cells are closely related to the pathogenesis of SLE. However, the role and mechanism of HCQ on Th17 cell differentiation in SLE is not clearly understood. Here, we investigate the effect of HCQ on Th17 cell differentiation bothin vitroand in patients with SLE.Methods.Twenty-five patients with SLE were divided into 2 treatment groups: prednisone alone and HCQ plus prednisone. Interleukin 17 (IL-17) expression was analyzed by ELISA and real-time (RT)-PCR. Th17 were measured in patients with SLE by flow cytometry before and after HCQ treatment.In vitro, naive T cells were cultured in Th17-inducing conditions with or without HCQ. Cell differentiation and IL-17 expression were analyzed. Finally, transcriptome sequencing identified differential gene expression between naive T cells and induced Th17 cells.Results.In patients, HCQ plus prednisone treatment inhibited IL-17 production, gene expression, and Th17 cell differentiation.In vitro, HCQ inhibited Th17 cell proliferation and differentiation, as well as IL-17 production. Five microRNA were significantly different in Th17 cells compared with naive T cells, and HCQ treatment reversed this effect.In vivo, microRNA-590 (miR-590) was verified and was significantly decreased in Th17 cells, compared with naive T cells from lupus-prone mice. Moreover, miR-590 was increased in patients treated with HCQ plus prednisone.Conclusion.HCQ inhibited Th17 cell differentiation and IL-17 production bothin vitroand in patients with SLE. Our study provides additional evidence for HCQ as a treatment for SLE.
Chapitre 2. L’embryon dans la législation relative à l’IVG
Authors: Vigneau Daniel 
Published: March 2018

Pendant très longtemps, la condition juridique de l’enfant conçu, de l’embryon ou du fœtus humain pour utiliser un langage emprunté à la biomédecine, a été dominée par deux principes majeurs : l’un, remontant au droit romain, permettant de le compter, par anticipation, parmi les êtres juridiquement existants, afin de lui accorder des droits, comme s’il était déjà né (maxime Infans conceptus ) ; l’autre, protégeant sa vie in utero et donc ses chances de naître par une incrimination pénale de l’avortement. La légalisation de l’avortement par la loi « Veil » du 17 janvier 1975 a bouleversé cette approche traditionnelle du droit. L’évolution législative postérieure a accentué le phénomène. La promotion de la liberté de la femme d’obtenir une interruption de grossesse s’est ainsi accompagnée corrélativement d’un déclin de la protection de l’embryon. En même temps, l’interruption volontaire de grossesse, reposant sur des techniques médicales, est devenue un moyen d’obtention, précieux pour la recherche, de cellules ou de tissus embryonnaires ou fœtaux. Supprimé d’un côté, l’embryon est finalement devenu d’un autre côté l’objet d’un enjeu médical et scientifique.
Georges Bataille, la mort et le jeu. Souveraineté du jeu et normativité du travail
Authors: Porcher Frédéric 
Published: March 2018

Cet article vise à interroger le sens et la portée de l’opposition entre le travail et le jeu chez Georges Bataille. En partant de ses deux sources, hégélienne et nietzschéenne, nous montrons que le sens de cette opposition est éminemment axiologique (souveraineté/servilité, sacré/profane) et qu’elle suppose, pour cette raison, une « mise en jeu » de soi-même à la limite de la vie et de la mort. Puis, nous cherchons à réévaluer cette axiologie bataillienne, séparant la part du travail de celle du jeu, en l’interrogeant à partir de la psychodynamique du jeu dans le travail contemporain.
Pierre Mertens, genèse d’un écrivain
Authors: Orban Jean-Pierre 
Published: March 2018

Pierre Mertens, né à Bruxelles en 1939, entre autres Prix Médicis 1987 pour Les Éblouissements (Paris, Le Seuil, 1987), est un écrivain francophone majeur, tant par l’ampleur et la variété de son œuvre que par sa place d’intellectuel en Belgique et son rapport à l’histoire mondiale du xxe siècle. Dans des extraits – remodelés pour Continents manuscrits – d’une biographie à paraître en octobre 2018 aux Impressions nouvelles, Jean-Pierre Orban décrit ici la genèse de l’écrivain, du creux de sa vie familiale à la publication de son premier roman aux Éditions du Seuil, en s’appuyant sur les archives personnelles de Pierre Mertens.
Dix ans dans la vie de Kateb Yacine, de Soliloques à Nedjma
Authors: Dugas Guy 
Published: March 2018

Entre absence de documents et mythes, parfois véhiculés par l’auteur lui-même, les conditions de la genèse de Nedjma (1956), roman majeur de la littérature maghrébine de langue française, demeurent obscures, plus de soixante ans après sa publication aux éditions du Seuil. Cet article, fondé sur des correspondances inédites des années 1946-1952, vise à faire le point sur cette énigme éditoriale – elle marque l’entrée en littérature de Kateb Yacine – et démontre notamment pourquoi cet écrivain du Seuil, souvent présenté comme un des auteurs phares de la collection « Méditerranée », ne publia pourtant jamais dans cette collection.
Is there difference between men and women motorcyclists?
Authors: Borstlap Hanneri , Saayman Melville 
Published: March 2018

Orientation: To broaden the literature, identify markets and determine the motives of these markets within South AfricaResearch purpose: The aim was to compare male and female motorcyclists’ socio-demographic and behavioural characteristics at a motorcycle festival in South Africa.Motivation of the study: There has been an increase in motorcycle sales and events and therefore motorcycle tourism, especially in South Africa. While from an international perspective, the socio-demographic and behavioural aspects of motorcyclists are well documented, what is lacking is literature on the behavioural aspects of motorcyclists and the differences between men and women.Research design, approach and method: The study was descriptive, and data were primarily collected through self-administered questionnaires. Independent t-tests and cross-tabulation analyses were used.Main findings: Four key motives were identified for attending the South Africa Bike Festival. The findings also confirmed that male and female motorcyclists differ from both socio-demographic and behavioural aspects and should be viewed as two distinctive segments. In addition, the research confirmed the importance of the age at which motorcyclists were exposed to motorcycling.Practical managerial implications: Marketing campaigns should focus on both segments and should appeal to all motivational factors that have been identified.Contribution: The study contributes to the motorcycle literature and provides a greater understanding of motorcyclists’ behaviour and what motivates them to attend a motorcycle festival. The research provides guidelines to event organisers to effectively market such an event. The research also identifies different segments to this event, which provides more indications on what the motorcyclist looks like.
Investigating selected self-management competencies of managers
Authors: Steyn Zandri , Van Staden Louis J. 
Published: March 2018

Orientation: Self-management serves as an essential managerial competency and entails taking responsibility for one’s own actions and behaviour. The problem is that managers who do not have effective self-management competencies may affect business adversely.Research purpose: The study investigated selected self-management competencies of managers within the manufacturing industry of South Africa.Motivation for the study: The researchers wanted to focus on selected self-management competencies of managers rather than all the managerial competencies.Research design, approach and method: A quantitative research method was employed by following a descriptive design and data were obtained using a well-structured self-administered questionnaire.Main finding: The results revealed that a significant and positive relation exists between managers’ integrity and ethical conduct, and between personal drive and resilience, as well as a significant positive relationship between work–life balance on the one hand and self-awareness and self-development on the other – all of which are components of their self-management competency.Practical/managerial implications: For managers to contribute to the success of a business, it is essential that they succeed in applying self-management competencies to distinguish them from their competitors.Contribution/value-add: No previous studies could be found investigating the relationship between integrity and ethical conduct, and between personal drive and resilience, as well as between work–life balance on the one hand and self-awareness and self-development on the other.
Comparative evaluation of salivary malondialdehyde levels as a marker of lipid peroxidation in early childhood caries
Authors: Subramanyam Divya , Gurunathan Deepa , Gaayathri R. , Vishnu Priya V. 
Published: March 2018

ABSTRACT
Objective: The aim of this study was to evaluate the association between lipid peroxidation and dental caries in children with ECC by estimating the levels of MDA in saliva of children. Materials and Methods: A total of 150 children were selected; 75 children with ECC and 75 children without caries (non-ECC). Saliva samples were collected and centrifuged at 12,000 rpm for 24 min at 4°C to obtain a supernatant. MDA levels were estimated by Buege and Aust method by using thiobarbituric acid. The data obtained were analyzed by Student’s t-test to compare MDA levels between the groups. Results: MDA levels were higher in children with ECC. There was no statistically significant difference between children with ECC and without ECC (non-ECC). Conclusion: MDA levels were slightly higher in children with ECC, indicating the role of lipid peroxidation in the carious process.