bluuebunny/crossref_metadata_2025_split huggingface dataset:
Introduciendo la dinámica de fluidos computacional en el análisis de flujos en medio poroso
Authors: Salcedo Ramón , Bayón Arnau , Chueca Patricia 
Published: February 2017

<p>Este trabajo presenta una introducción a la modelización con Dinámica de Fluidos Computacional (CFD) de un fluido atravesando un medio poroso. Para ello, se propone un caso práctico mediante la simulación de un flujo de aire producido por el ventilador de un pulverizador hidráulico asistido por aire que atraviesa un medio poroso (la vegetación). El trabajo consiste en dotar de las herramientas necesarias para configurar un modelo CFD para, posteriormente, ajustar la resistencia de la porosidad al paso de la corriente usando datos experimentales. El ajuste contempla tres escenarios: uno, considerando sólo pérdidas inerciales iguales entre los diferentes cuerpos porosos, dos, considerando dichas pérdidas inerciales más las pérdidas viscosas y, tres, considerando sólo pérdidas inerciales diferentes entre los diferentes cuerpos porosos. Finalmente, se comparan las velocidades obtenidas en cada simulación con datos reales, eligiéndose aquella configuración que arroja mayores ajustes. La metodología planteada pretende poner de manifiesto la importancia de usar con criterio los distintos parámetros propios de la configuración de modelos CFD.</p>
Discoloration Effects of Traditional Turkish Beverages on different Composite Restoratives
Authors: Baglar Serdar , Keskin Erol , Orun Tahir , Es Abdulhamit 
Published: February 2017

ABSTRACT

Aim
The aim of this study was to evaluate the discoloring effects of five beverages including, especially, traditional Turkish ones on five commonly used dental composites by using a spectrophotometer device.

Materials and methods
Five methacrylate-based composites (shade A2) were selected to evaluate their color stability (175 disk samples). Four of them (Filtek Ultimate Universal, Clearfil Majesty ES-2, Tetric EvoCeram, and Cavex Quadrant Universal LC) were nanofilled universal composites for both anterior and posterior restorations, and one (Clearfil Majesty Posterior) was nano-superfilled for posterior restorations. The tested beverages were tamarind syrup, ottoman syrup, turnip juice, pomegranate juice, and distilled water (control). All samples were kept in an incubator at 37°C for 12 days (measured at 3rd, 6th, 12th day intervals) in immersion solutions which was equivalent to 1 year in vivo. Color measurements were made with VITA Easyshade Advance (Vident, Brea, CA) spectrophotometer device according to CIE L*a*b* system. Statistical analysis was performed with analysis of variance and least significant difference test to analyze differences in L*a*b* and ΔE values.

Results
All materials showed significant discoloration (p < 0.05) when compared with the control group. The highest ΔE was observed in turnip juice, whereas ottoman syrup had the lowest ΔE. Tetric EvoCeram showed the lowest ΔE, while Clearfil Majesty ES-2 showed the highest ΔE.

Conclusion
In all the groups tested, clinically unacceptable ΔE values were obtained. Although color stability of methacrylatebased composites has been widely investigated, this has not been done before with these kinds of immersion solutions.

Clinical significance
Potential discoloration might be limited by dietary adjustments based on in vitro evaluations.

How to cite this article
Baglar S, Keskin E, Orun T, Es A. Discoloration Effects of Traditional Turkish Beverages on different Composite Restoratives. J Contemp Dent Pract 2017;18(2): 83-93.
An evaluation of Employee Commitment of Part-Time Faculty (PTF) in Hong Kong’s Continuing Professional Development (CPD) Sector
Authors: Li KS , Wong Anthony , Tong Canon 
Published: February 2017

Economic crises in recent years have exposed the presence of a large number of poorly educated workers who can barely meet the needs of Hong Kong’s knowledge-based economy. In response, in April 2002 the HKSAR Government set up a HK$5 billion Continuing Education Fund to encourage and subsidize those who want to improve themselves through continuing education. This policy presents unprecedented opportunities for continuing professional development (CPD) course providers. To grasp these opportunities, they must act quickly to develop program mixes that match the education needs of potential students and demonstrate excellence in teaching quality by recruiting and retaining well-qualified faculty. As the majority of the courses are designed for those who seek to improve themselves after work, most of the courses are extramural courses conducted by part-time faculty (PTF). Recruitment of PTF raises an employee commitment problem which might affect their performance in teaching and also subsequently the effectiveness of those part-time courses. In addition, the various backgrounds of PTF also might affect the effectiveness of delivering of those CPD courses. So the objectives of this study are to examine the extent of employee commitment of those part-time staff and also the relations of their background towards the employee commitment. A quantitative study was used by applying Wang’s (2004) five-component commitment model to test employee commitment of PTF in Hong Kong. An online questionnaire was used to collect sample data from a population of PTF working at the 450 registered CPD course providers in Hong Kong. The data were analyzed and tested by means of factor analysis, correlation tests and structural equation modeling (SEM). Based on the data collected from 270 respondents, the study suggests that Wang’s five-component model is better than other models for explaining employee commitment in Hong Kong’s CPD industry. All five components of employee commitment of PTF and demographic variables were concluded to have no association with passive continuance commitment, but have varying levels of influences on different components of employee commitment.
To Survive and Thrive under Hypercompetition: An Exploratory Analysis of the Influence of Strategic Purity on Truckload Motor-Carrier Financial Performance
Authors: Jin Yao “Henry” , Swanson David , Waller Matthew , Ozment John 
Published: February 2017

AbstractEasy access to equipment and low barriers to entry have led to an intensely competitive truckload industry in which carriers possess little power to increase prices consistent with inflation. Yet, the heterogeneous performance among TL carriers indicates that sustained success in such a hypercompetitive industry is possible. Under the strategic purity framework, this research adopts a multimethod approach by first utilizing panel of financial and operational data composed of 828 firm-quarter observations and finds that the relationship between a popular industry metric—the trailer-to-tractor ratio (T2T)—and performance is convex. Empirical results are further explained by interviews with senior executives and industry analysts. This research contributes to theory and practice by first showing that, consistent with the strategic management literature, strategy-driven heterogeneous configuration of common assets may increase performance. Second, we show that strategic purity allows carriers supernormal financial performance, despite the hypercompetitive environment. Third, as the TL industry becomes increasingly conscious of competitive strategies, our study shows that the T2T can be used as a guide for carriers to align their competitive strategy with asset configuration.
Shallow Subsurface Evidence for Postglacial Holocene Lakes at Ivanpah Dry Lake: An Alternative Energy Development Site in the Central Mojave Desert, California, USA
Authors: Sims Douglas B. , Spaulding W. Geoffrey 
Published: February 2017

Dry lakes, or playas, in the American Southwest have become important locations for alternative energy solar electric generation systems. Many of these playas have not been investigated for past environmental conditions prior to their development, causing alterations to the shallow sediment profile and altering subsurface chemical and physical data important to recent geologic and hydrologic histories of these areas. Recent studies of these features commonly have focused on surficial data with little or no subsurface geologic data to delineate wet and dry cycles of playa lakes. Many of the playa margins are covered with a surficial layer of alluvial and/or aeolian sands varying in thickness, which could interfere with correct interpretations of data gathered only on the surface material on these lands. Over the past 13,000 years Ivanpah Dry Lake has had at least three episodes of lake highstands up to ~10m in response to climate changes, based on data in this study with the oldest episode dates to ~13,000 cal yrs BP. This study has a link to other sites as many other playas are slated for energy development and could endure subsurface data alteration during site reworking and occupation, resulting in a loss in their collective historical geologic and hydrologic records if more complete studies of important sites are not carried out before developments begin.
Dynamic contribution of recycled components from the subducted Pacific slab: Oxygen isotopic composition of the basalts from 106 Ma to 60 Ma in North China Craton
Authors: Liu Jia , Wang Zi‐Zhen , Yu Hao‐Ran , Xia Qun‐Ke , Deloule Etienne , Feng Min 
Published: February 2017

AbstractHow the materials derived from the stagnant Pacific slab contributed to the mantle sources of the mafic rocks in east China is still in hot debate. In this work, δ18O (Vienna standard mean ocean water) values of clinopyroxene phenocrysts in the oceanic island basalts (OIB)‐type mafic rocks from 106 Ma to 60 Ma in the east North China Craton (NCC) were measured by secondary ion mass spectrometry. Our data show that for all of the samples, the δ18Ocpx are dominantly higher than that of the clinopyroxene from normal mid‐oceanic ridge basalt (5.4–5.8‰), which confirms the role of recycled oceanic crust (ROC) in their mantle sources. Combining the δ18O data of basalts and the lithospheric mantle in the literature, we found that in the southeast NCC, upper and lower ROC components alternately appeared in the mantle sources of basalts, but these ROC components are consistently different from that in the lithospheric mantle, while in the northern NCC, the recycled components in the sources seem to be persistently from upper ROC. These observations suggest that (1) these mafic OIB‐type rocks are most likely derived from the convective asthenosphere and (2) the contribution of components from the Pacific oceanic slab into the NCC upper mantle was dynamic, without a simple temporal trend. This new knowledge calls for the reconsideration of the existing models of the thinning process of the NCC lithospheric mantle, and it warns against simply using the chemical composition of basalts to infer the evolution of lithosphere.
Eocene adakitic porphyries in the central‐northern Qiangtang Block, central Tibet: Partial melting of thickened lower crust and implications for initial surface uplifting of the plateau
Authors: Ou Quan , Wang Qiang , Wyman Derek A. , Zhang Hai‐Xiang , Yang Jin‐Hui , Zeng Ji‐Peng , Hao Lu‐Lu , Chen Yi‐Wei , Liang He , Qi Yue 
Published: February 2017

AbstractThe time and mechanism of crustal thickening and initial surface uplift of the Tibetan Plateau remain highly controversial. Here we report on zircon U‐Pb age, and mineral, element, and Sr‐Nd isotope composition data for Eocene adakitic porphyries in the Laorite Co area of central‐northern Qiangtang Block, central Tibet. Laser ablation‐inductively coupled plasma‐mass spectrometry zircon U‐Pb age dating shows that the porphyries were generated at 42–41 Ma. All samples display adakitic geochemical characteristics, such as high SiO2 and Al2O3, and low Y and Yb contents, and high Sr/Y and La/Yb ratios with positive Sr and negligible Eu anomalies and Nb‐Ta depletion. They also have low magnesium number (Mg #) (16–45) and high K2O (4.0–4.6 wt %) values, as well as high (87Sr/86Sr)i (0.7076–0.7080) and low εNd(t) (−5.9 to −4.4) values. These adakitic rocks were most probably generated by partial melting of thickened lower crust in the stability field of garnet, amphibole, and rutile but with relatively minor plagioclase. Moreover, such a crustal thickening process beneath this block likely occurred no later than the middle Eocene and was most probably caused by the southward subduction of the Songpan‐Ganzi Block in the early Cenozoic. In addition, the occurrences of exposed adakitic porphyries unambiguously indicate that exhumation process occurred after their formation. Thus, these ~42 Ma adakitic porphyries indicate the occurrence of significant exhumation since 42 Ma. Integrated with the thermochronological and paleoelevation data, we suggest that the initial surface uplift of the Qiangtang Block, triggered by crustal thickening, was underway by the middle Eocene (~42 Ma).
Remagnetization of the Paleogene Tibetan Himalayan carbonate rocks in the Gamba area: Implications for reconstructing the lower plate in the India‐Asia collision
Authors: Huang Wentao , Lippert Peter C. , Jackson Michael J. , Dekkers Mark J. , Zhang Yang , Li Juan , Guo Zhaojie , Kapp Paul , van Hinsbergen Douwe J. J. 
Published: February 2017

AbstractThe characteristic remanent magnetization (ChRM) isolated from Paleogene carbonate rocks of the Zongpu Formation in Gamba (28.3°N, 88.5°E) of southern Tibet has previously been interpreted to be primary. These data are pertinent for estimating the width of Greater India and dating the initiation of India‐Asia collision. We have reanalyzed the published ChRM directions and completed thorough rock magnetic tests and petrographic observations on specimens collected throughout the previously investigated sections. Negative nonparametric fold tests demonstrate that the ChRM has a synfolding or postfolding origin. Rock magnetic analyses reveal that the dominant magnetic carrier is magnetite. “Wasp‐waisted” hysteresis loops, suppressed Verwey transitions, high frequency‐dependent in‐phase magnetic susceptibility, and evidence that >70% of the ferrimagnetic material is superparamagnetic at room temperature are consistent with the rock‐magnetic fingerprint of remagnetized carbonate rocks. Scanning electron microscopy observations and energy‐dispersive X‐ray spectrometry analysis confirm that magnetite grains are authigenic. In summary, the carbonate rocks of the Zongpu Formation in Gamba have been chemically remagnetized. Thus, the early Paleogene latitude of the Tibetan Himalaya and size of Greater India have yet to be determined and the initiation of collision cannot yet be precisely dated by paleomagnetism. If collision began at 59 ± 1 Ma at ~19°N, as suggested by sedimentary records and paleomagnetic data from the Lhasa terrane, then a huge Greater India, as large as ~3500–3800 km, is required in the early Paleogene. This size, in sharp contrast to the few hundred kilometers estimated for the Early Cretaceous, implies an ever greater need for extension within Greater India during the Cretaceous.
Tracking nitrous oxide emission processes at a suburban site with semicontinuous, in situ measurements of isotopic composition
Authors: Harris Eliza , Henne Stephan , Hüglin Christoph , Zellweger Christoph , Tuzson Béla , Ibraim Erkan , Emmenegger Lukas , Mohn Joachim 
Published: February 2017

AbstractThe isotopic composition of atmospheric nitrous oxide (N2O) was measured semicontinuously, at ∼35 min frequency in intermittent periods of 1–6 days over one and a half years, using preconcentration coupled to a quantum cascade laser spectrometer at the suburban site of Dübendorf, Switzerland. The achieved measurement repeatability was 0.08‰, 0.11‰, and 0.10‰ for δ18O, site preference, and δ15Nbulk respectively, which is better than or equal to standard flask sampling‐based isotope ratio mass spectrometry performance. The observed mean diurnal cycle reflected the buildup of N2O from isotopically light sources on an isotopically heavy tropospheric background. The measurements were used to determine the source isotopic composition, which varied significantly compared to chemical and meteorological parameters monitored at the site. FLEXPART‐COSMO transport modeling in combination with modified Emissions Database for Global Atmospheric Research inventory emissions was used to model N2O mole fractions at the site. Additionally, isotopic signatures were estimated for different source categories using literature data and used to simulate N2O isotopic composition over the measurement period. The model was able to capture variability in N2O mole fraction well, but simulations of isotopic composition showed little agreement with observations. In particular, measured source isotopic composition exhibited one magnitude larger variability than simulated, clearly indicating that the range of isotopic source signatures estimated from literature significantly underestimates true variability of source signatures. Source δ18O signature was found to be the most sensitive tracer for urban/industry versus agricultural N2O. δ15Nbulk and site preference may provide more insight into microbial and chemical emission processes than partitioning of anthropogenic source categories.
Greenhouse gas balance over thaw‐freeze cycles in discontinuous zone permafrost
Authors: Wilson R. M. , Fitzhugh L. , Whiting G. J. , Frolking S. , Harrison M. D. , Dimova N. , Burnett W. C. , Chanton J. P. 
Published: February 2017

AbstractPeat in the discontinuous permafrost zone contains a globally significant reservoir of carbon that has undergone multiple permafrost‐thaw cycles since the end of the mid‐Holocene (~3700 years before present). Periods of thaw increase C decomposition rates which leads to the release of CO2 and CH4 to the atmosphere creating potential climate feedback. To determine the magnitude and direction of such feedback, we measured CO2 and CH4 emissions and modeled C accumulation rates and radiative fluxes from measurements of two radioactive tracers with differing lifetimes to describe the C balance of the peatland over multiple permafrost‐thaw cycles since the initiation of permafrost at the site. At thaw features, the balance between increased primary production and higher CH4 emission stimulated by warmer temperatures and wetter conditions favors C sequestration and enhanced peat accumulation. Flux measurements suggest that frozen plateaus may intermittently (order of years to decades) act as CO2 sources depending on temperature and net ecosystem respiration rates, but modeling results suggest that—despite brief periods of net C loss to the atmosphere at the initiation of thaw—integrated over millennia, these sites have acted as net C sinks via peat accumulation. In greenhouse gas terms, the transition from frozen permafrost to thawed wetland is accompanied by increasing CO2 uptake that is partially offset by increasing CH4 emissions. In the short‐term (decadal time scale) the net effect of this transition is likely enhanced warming via increased radiative C emissions, while in the long‐term (centuries) net C deposition provides a negative feedback to climate warming.
High‐performance reactive silver‐ion adsorption and reductive performance of poly(N‐methylaniline)
Authors: Jiang Shun‐Hua , Wu Jun‐Xiong , Zhou Jing , Lü Qiu‐Feng 
Published: February 2017

AbstractSelf‐assembled poly(N‐methylaniline) (PNMA) microspheres were prepared in a facile way by an unstirred polymerization of N‐methylaniline monomers with ammonium persulfate as an oxidizing agent at different temperatures. The polymers were characterized by FTIR and UV‐vis spectroscopy, SEM, TEM and wide‐angle X‐ray diffraction. Furthermore, adsorption property of PNMA microspheres for silver ions from aqueous solution was investigated by batch experiments. The results revealed that PNMA showed a high‐performance adsorption for silver ions by chelation and redox reaction. The maximum adsorption capacity was up to 2.460 g/g for silver ions on PNMA microspheres prepared at 0°C, at an initial silver ion concentration of 160 mmol/L at 25°C for 48 hr. The adsorption process fits the pseudo‐second‐order kinetics and Freundlich isotherm models. Moreover, the PNMA microspheres exbihit high reductive performances for Au(III) and Pd(II) ions. Therefore, the PNMA microspheres have great potential application in removal and recovery of metal ions from industrial wastewater.
Safety of long‐term intranasal budesonide delivered via the mucosal atomization device for chronic rhinosinusitis
Authors: Manji Jamil , Singh Gurkaran , Okpaleke Christopher , Dadgostar Anali , Al‐Asousi Fahad , Amanian Ameen , Macias‐Valle Luis , Finkelstein Andres , Tacey Mark , Thamboo Andrew , Javer Amin 
Published: February 2017

BackgroundAlthough short‐term use (≤2 months) of atomized topical nasal steroids has been shown to be safe and effective, the long‐term safety has yet to be demonstrated. The aim of this study was to determine the impact of long‐term topical budesonide treatment via the mucosal atomization device (MAD) on the hypothalamic‐pituitary‐adrenal axis (HPAA) and intraocular pressure (IOP).MethodsA cross‐sectional study of patients with chronic rhinosinusitis (CRS), with or without nasal polyposis, managed with daily nasal budesonide via MAD was conducted at a tertiary rhinology center. Patients using systemic steroids within 3 months of assessment were excluded. HPAA impact was assessed using the cosyntropin stimulation test for adrenal function and a survey of relevant symptomatology. Patients also underwent tonometry to assess for elevated IOP potentially related to corticosteroid use.ResultsA total of 100 CRS patients were recruited with a mean budesonide treatment duration of 23.5 months (range, 6–37 months). Stimulated cortisol response was diminished in 3 patients (3%). No patients with adrenal suppression had relevant symptomatology. IOP was elevated in 6 patients (6%).ConclusionThese findings suggest that there is a risk of adrenal suppression and raised IOP associated with the long‐term use of topical nasal budesonide via MAD. Otolaryngologists should consider periodic surveillance for these adverse events in this patient cohort.
Polyhalides as Efficient and Mild Oxidants for Oxidative Carbene Organocatalysis by Radical Processes
Authors: Wu Xingxing , Zhang Yuexia , Wang Yuhuang , Ke Jie , Jeret Martin , Reddi Rambabu N. , Yang Song , Song Bao‐An , Chi Yonggui Robin 
Published: February 2017

AbstractSimple and inexpensive polyhalides (CCl4 and C2Cl6) have been found to be effective and versatile oxidants in removing electrons from Breslow intermediates under N‐heterocyclic carbene (NHC) catalysis. This oxidative reaction involves multiple single‐electron‐transfer (SET) processes and several radical intermediates. The α, β, and γ‐carbon atoms of aldehydes and enals could be readily functionalized. Given the low cost of the oxidants and the broad applicability of the reactions, this study is expected to greatly enhance the feasibility of oxidative NHC catalysis for large‐scale applications. Also this new SET radical process with polyhalides as single‐electron oxidants will open a new avenue in the development of NHC‐catalyzed radical reactions.