bluuebunny/crossref_metadata_2025 huggingface dataset:
Vicarious Radiometric Calibration of the Hyperspectral Imaging Microsatellites SPARK-01 and -02 over Dunhuang, China
Authors: Zhang Hao , Zhang Bing , Chen Zhengchao , Huang Zhihua
Published: January 2018

Two wide-swath hyperspectral imaging microsatellites, SPARK-01 and -02, were launched on 22 December 2016. Radiometric calibration coefficients were determined for these two satellites via a calibration experiment performed from the end of February to the beginning of March 2017 at the high-altitude, homogenous Dunhuang calibration site in the Gobi Desert in China. In-situ measurements, including ground reflectance, direct transmittance, diffuse-to-global irradiance ratio, and radiosonde vertical profile, were acquired. A unique relative calibration procedure was developed using actual satellite images. This procedure included dark current computation and non-uniform correction processes. The former was computed by averaging multiple lines of long strip imagery acquired over open oceans during nighttime, while the latter was computed using images acquired after the adjustment of the satellite yaw angle to 90°. This technique was shown to be suitable for large-swath satellite image relative calibration. After relative calibration, reflectance, irradiance, and improved irradiance-based methods were used to conduct absolute radiometric calibrations in order to predict the top-of-atmosphere (TOA) radiance. The SPARK-01 and -02 satellites passed over the calibration site on 7 March and 28 February 2017, during which time fair and non-ideal weather occurred, respectively. Thus, the SPARK-01 calibration coefficient was derived using reflectance- and irradiance-based methods, while that of SPARK -02 was derived using reflectance- and improved irradiance-based methods. The sources of calibration uncertainty, which include aerosol-type assumptions, transmittance measurements, water vapor content retrieval, spectral wavelength shift and satellite image misregistration, were explored in detail for different calibration methods. Using the reflectance and irradiance-based methods, the total uncertainty for SPARK-01 was estimated to be 4.7% and 4.1%, respectively, in the <1000 nm spectral range. For SPARK-02, total uncertainties of 8.1% and of 5.9% were estimated using the reflectance- and improved irradiance-based methods, respectively. The calibration methods were also verified using MODIS images, which confirmed that the calibration accuracies were within the expected range. These in-situ measurements, analyses, and results provide a basis for in-orbit radiometric calibration of the SPARK-01 and -02 satellites. These experiments strongly support the use of diffuse-to-global ratio measurements in in-situ vicarious calibration experiments and the addition of spectrally continuous measurements for direct transmittance, which is important for hyperspectral satellite sensors.
Econometric Modeling of SME Performance. Case of Romania
Authors: Batrancea Ioan , Morar Ioan-Dan , Masca Ema , Catalin Sabau , Bechis Liviu
Published: January 2018

In the present study, we analyzed the financial equilibrium factors that have a major impact on SME financial performance, as this performance is considered to have played a pivotal role in Romania’s recovery from the economic crisis. Thus, we built econometric models based on return on assets and return on sales in five economic sectors, i.e., pharmaceuticals, furniture manufacturing, leather garment factories, software firms and textile factories. We show how the enterprises’ performance was influenced by the independent variables of the equilibrium: fixed assets, current assets, inventory, receivables, equity and liabilities. The results indicate that return on assets is influenced by the current assets ratio and the inventory ratio in all models, as well as by the equity-to-total liabilities ratio in 80% of the models. We also notice that assets ratios have the highest influence on performance evaluation, namely inventory ratio in all models and current assets ratio in 87.5% of the models. In addition, liabilities ratios influence performance as follows: equity-to-total liabilities ratio in 80% of the models and total debt-to-assets ratio in 35% of the models.
How Symmetric Are Real-World Graphs? A Large-Scale Study
Authors: Ball Fabian , Geyer-Schulz Andreas
Published: January 2018

The analysis of symmetry is a main principle in natural sciences, especially physics. For network sciences, for example, in social sciences, computer science and data science, only a few small-scale studies of the symmetry of complex real-world graphs exist. Graph symmetry is a topic rooted in mathematics and is not yet well-received and applied in practice. This article underlines the importance of analyzing symmetry by showing the existence of symmetry in real-world graphs. An analysis of over 1500 graph datasets from the meta-repository networkrepository.com is carried out and a normalized version of the “network redundancy” measure is presented. It quantifies graph symmetry in terms of the number of orbits of the symmetry group from zero (no symmetries) to one (completely symmetric), and improves the recognition of asymmetric graphs. Over 70% of the analyzed graphs contain symmetries (i.e., graph automorphisms), independent of size and modularity. Therefore, we conclude that real-world graphs are likely to contain symmetries. This contribution is the first larger-scale study of symmetry in graphs and it shows the necessity of handling symmetry in data analysis: The existence of symmetries in graphs is the cause of two problems in graph clustering we are aware of, namely, the existence of multiple equivalent solutions with the same value of the clustering criterion and, secondly, the inability of all standard partition-comparison measures of cluster analysis to identify automorphic partitions as equivalent.
How to Disable Mortal Loops of Enterprise Resource Planning (ERP) Implementation: A System Dynamics Analysis
Authors: Cyrus Kaveh , Aloini Davide , Karimzadeh Samira
Published: January 2018

Successful Enterprise Resource Planning (ERP) implementation depends upon various factors known as critical success factors (CSFs). This study developed a system dynamics model of ERP implementation based on CSFs to discuss ERP implementation complexities, which identifies the effect of CSF interrelations on different aspects of ERP project failure. Based on the model hypothesis, CSF interrelations include many causal loop dependencies. Some of these causal loops are called mortal loops, because they may cause the failure of risk reduction efforts to a more severe failure in effect of lack of system thinking on CSFs interrelations. This study discusses how system thinking works as a leverage point for overcoming ERP implementation challenges.
To Investigate the Flow Structure of Discontinuous Vegetation Patches of Two Vertically Different Layers in an Open Channel
Authors: Anjum Naveed , Ghani Usman , Ahmed Pasha Ghufran , Latif Abid , Sultan Tahir , Ali Shahid
Published: January 2018

In the present study, the flow structure of discontinuous double-layered vegetation patches was investigated using a 3D Reynolds stress turbulence model (RSM). The channel domain was built using GAMBIT (Geometry and Mesh Building Intelligent Toolkit). For the simulation and postprocessing, FLUENT (ANSYS) was used to analyze the distribution of the mean velocity, Reynolds stresses, and other flow properties against two different flow conditions. The results captured by the turbulence model at specific locations and the cross section are presented in the form of various velocity profiles and contour plots. In the gap portion, the velocity was visibly lower than that in the vegetation areas, while the influence of patch distribution was not visible in the overlying flow layer. The velocity profiles at critical locations were categorized by numerous modulation points and velocity projections close to the bed, principally for positions straight after the vegetation structures. A distinction in the velocity at the topmost of the smaller vegetation structure was prominent. Reynolds stresses, turbulent kinetic energy, and turbulence intensity exhibited large fluctuations inside the vegetation regions and just behind the vegetation structures compared with in the gap regions.
Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting: combining renewable raw materials with clean fuels
Authors: Krüger Stefanie , Schwarze Michael , Baumann Otto , Günter Christina , Bruns Michael , Kübel Christian , Szabó Dorothée Vinga , Meinusch Rafael , Bermudez Verónica de Zea , Taubert Andreas
Published: January 2018

The synthesis, structure, and photocatalytic water splitting performance of two new titania (TiO2)/gold(Au)/Bombyx mori silk hybrid materials are reported. All materials are monoliths with diameters of up to ca. 4.5 cm. The materials are macroscopically homogeneous and porous with surface areas between 170 and 210 m2/g. The diameter of the TiO2 nanoparticles (NPs) – mainly anatase with a minor fraction of brookite – and the Au NPs are on the order of 5 and 7–18 nm, respectively. Addition of poly(ethylene oxide) to the reaction mixture enables pore size tuning, thus providing access to different materials with different photocatalytic activities. Water splitting experiments using a sunlight simulator and a Xe lamp show that the new hybrid materials are effective water splitting catalysts and produce up to 30 mmol of hydrogen per 24 h. Overall the article demonstrates that the combination of a renewable and robust scaffold such as B. mori silk with a photoactive material provides a promising approach to new monolithic photocatalysts that can easily be recycled and show great potential for application in lightweight devices for green fuel production.
The Enigmatic (Almost) Dark Galaxy Coma P: The Atomic Interstellar Medium
Authors: Ball Catherine , Cannon John M. , Leisman Lukas , Adams Elizabeth A. K. , Haynes Martha P. , Józsa Gyula I. G. , McQuinn Kristen B. W. , Salzer John J. , Brunker Samantha , Giovanelli Riccardo , Hallenbeck Gregory , Janesh William , Janowiecki Steven , Jones Michael G. , Rhode Katherine L.
Published: January 2018

We present new high-resolution H i spectral line imaging of Coma P, the brightest H i source in the system HI 1232+20. This galaxy with extremely low surface brightness was first identified in the ALFALFA survey as an “(Almost) Dark” object: a clearly extragalactic H i source with no obvious optical counterpart in existing optical survey data (although faint ultraviolet emission was detected in archival GALEX imaging). Using a combination of data from the Westerbork Synthesis Radio Telescope and the Karl G. Jansky Very Large Array, we investigate the H i morphology and kinematics at a variety of physical scales. The H i morphology is irregular, reaching only moderate maxima in mass surface density (peak

pc−2). Gas of lower surface brightness extends to large radial distances, with the H i diameter measured at 4.0 ± 0.2 kpc inside the

pc−2 level. We quantify the relationships between mass surface density of H i gas and star formation on timescales of ∼100–200 Myr as traced by GALEX far-ultraviolet emission. While Coma P has regions of dense H i gas reaching the

cm−2 level typically associated with ongoing star formation, it lacks massive star formation as traced by Hα emission. The H i kinematics are extremely complex: a simple model of a rotating disk cannot describe the H i gas in Coma P. Using spatially resolved position–velocity analysis we identify two nearly perpendicular axes of projected rotation that we interpret as either the collision of two H i disks or a significant infall event. Similarly, three-dimensional modeling of the H i dynamics provides a best fit with two H i components. Coma P is just consistent (within 3σ) with the known

scaling relation. It is either too large for its H i mass, has too low an H i mass for its H i size, or the two H i components artificially extend its H i size. Coma P lies within the empirical scatter at the faint end of the baryonic Tully–Fisher relation, although the complexity of the H i dynamics complicates the interpretation. Along with its large ratio of H i to stellar mass, the collective H i characteristics of Coma P make it unusual among known galaxies in the nearby universe.
Advanced Diagnostics for the Study of Linearly Polarized Emission. I. Derivation
Authors: Herron C. A. , Gaensler B. M. , Lewis G. F. , McClure-Griffiths N. M.
Published: January 2018

Linearly polarized emission is described, in general, in terms of the Stokes parameters Q and U, from which the polarization intensity and polarization angle can be determined. Although the polarization intensity and polarization angle provide an intuitive description of the polarization, they are affected by the limitations of interferometric data, such as missing single-dish data in the u–v plane, from which radio-frequency interferometric data is visualized. To negate the effects of these artifacts, it is desirable for polarization diagnostics to be rotationally and translationally invariant in the Q–U plane. One rotationally and translationally invariant quantity, the polarization gradient, has been shown to provide a unique view of spatial variations in the turbulent interstellar medium when applied to diffuse radio-frequency synchrotron emission. In this paper, we develop a formalism to derive additional rotationally and translationally invariant quantities. We present new diagnostics that can be applied to diffuse or point-like polarized emission in any waveband, including a generalization of the polarization gradient, the polarization directional curvature, polarization wavelength derivative, and polarization wavelength curvature. In Paper II, we will apply these diagnostics to observed and simulated images of diffuse radio-frequency synchrotron emission.
Propagande catholique et anticommunisme rural
Authors: Knerr Frédéric
Published: January 2018

L’ancrage de la doctrine communiste dans le monde des campagnes fut un phénomène rare mais particulièrement marqué en Lot-et-Garonne au début des années 1920. Dans les paroisses directement confrontées au communisme, les catholiques se réorganisent en proposant une contre-propagande active qui passe par un engagement collectif ou individuel afin d’en limiter l’expansion.
Quelques repères pour une épistémologie du droit canonique
Authors: Greiner Philippe
Published: January 2018

Après la période médiévale, le droit canonique a été très influencé par l’approche du droit public ecclésiastique. La principale préoccupation pour l’Église était d’affirmer sa propre souveraineté par rapport à l’État. Le Code de droit canonique de 1983 a reçu les enseignements du concile Vatican II concernant l’ecclésiologie. Au plan épistémologique, un rapport étroit se dégage désormais entre théologie et droit canonique, nature juridique et équité canonique.
Synthesis of Zeolite A from Mongolian Coal Fly Ash by Hydrothermal Treatment
Authors: Rentsenorov Ulambayar , Davaabal Batmunkh , Temuujin Jadambaa
Published: January 2018

Raw coal fly ash and acid pretreated fly ash were used to synthesize A-type zeolite by hydrothermal treatment. In order to synthesize zeolite A an aqueous gel having a molar batch composition of Na2O:Al2O3:1.926SiO2:128H2O was utilized. Fly ash and zeolitic products were characterized by SEM, XRF, XRD and cation exchange capacity (CEC). After hydrothermal treatment, several types of zeolites were formed: zeolite A, analcime, faujasite and hydroxy-sodalite. The highest content of zeolite A was formed in the mixture treated at 80°C for 8 hours. CEC values of the zeolitic products were 28-38 times higher than that of in raw fly ash. Acid pretreatment which leads to low calcium and iron content is preferable method for processing of fly ash for the zeolite synthesis. Synthesized zeolite can be used for ion exchangers for water treatment.
Characterization of Glass Ceramics Produced from Natural and Waste Raw Materials
Authors: Bayarzul Uyat , Temuujin Jadambaa
Published: January 2018

Glass ceramics were prepared from fly ash, waste window glass and fluorite rawmaterials. Mixtures of raw materials were melted at 1300, 1400 and 1500 °C for 4 h and quenchedin cold water. The crystallization behavior of glass ceramics was investigated by differentialthermal analysis-thermogravimetry (DTA-TG). Crystallization at various temperatures (700, 800,900 and 1000 °C) for 30 min was used to obtain the glass ceramics. The obtained glass ceramicswere characterized by X-ray diffraction (XRD), light microscopy and hardness test. XRD studyrevealed that the crystallized phases were plagioclase-type minerals (diopside and albite). TheVickers hardness of the glass ceramics increased from 0.80±0.19 GPa to 6.35±0.35GPa and densityranged from 1.44 g/cm3 to 2.42 g/cm3 depending on the treatment temperature. Glass ceramicsprepared from fused glass melted at 1500 °C temperature showed the highest hardness comparedwith those melted at lower temperatures.
Computer Modeling of the Formation Process of Core-Shell Nanoparticles Cu@Si
Authors: Yumozhapova Natalia V. , Nomoev Andrey V. , Gafner Yuri Ya
Published: January 2018

The process of nanoparticle Cu@Si formation by the molecular dynamic method using MEAM-potentials was studied. Modeling the droplet behavior demonstrates that a core-shell structure with a copper core and a silicon shell can be formed if the drop is in the liquid state, until the material is finally redistributed. The parameters of thermal stability of Cu@Si composite nanoparticles of different sizes have been determined. It is concluded that as the temperature increases, the diffusion of copper atoms to the surface begins, which leads to a change in the structure and the formation of particles with a core of the Cu@Si type.
Modification of Materials by Carbon Nanoparticles
Authors: Shpilevsky E.M. , Penyazkov O , Filatov S. , Shilagardi G. , Tuvshintur P. , Timur-Bаtor D. , Ulam-Orgikh D.
Published: January 2018

The physical and chemical principles of the preparation of carbon nanoparticles (fullerenes, carbon nanotubes) and their complexes, and the methods for introducing nanoparticles into metal, ceramic and polymer matrices are considered. The most important properties of some materials containing these cluster molecules are given. It is shown that the introduction of carbon nanoparticles into materials, even in small fractions (up to 1.0 wt. %), significantly in some cases, at times alters their structure, electrical and tribological properties.
Structural and Vibrational Properties of Crystals with a Rare-Earth Sublattice: Ab Initio Calculations
Authors: Petrov Vladislav P. , Chernyshev Vladimir A. , Nikiforov Anatoly E.
Published: January 2018

We investigated the crystal structure, vibrational and elastic properties of crystals with a rare-earth sublattice related to different structural types at ab initio level of modeling: elpasolite Cs2NaRF6 −> pyrochlore R2Ti2O7 −> ferroborate RFe3(BO3)4, where R is a rare-earth ion or yttrium. The calculations were performed in the framework of a density functional theory using the hybrid functionals containing local and non-local contribution (i.e. Hartree-Fock exchange term) to the exchange energy. We used CRYSTAL program for simulating periodic structures in the MO LCAO approximation. To describe the internal shell of a rare-earth ion up to 4f, we used the nonrelativistic pseudopotential («4f-in-core») that describes the effect of internal electrons on the outer valence shells. The results of the calculations are in good agreement with the available experimental data of IR and Raman experiments, X-ray diffraction analysis for the rows of elpasolites, pyrochlores and ferroborates.
Biased Generation and In Situ Activation of Lung Tissue–Resident Memory CD4 T Cells in the Pathogenesis of Allergic Asthma
Authors: Turner Damian L. , Goldklang Monica , Cvetkovski Filip , Paik Daniel , Trischler Jordis , Barahona Josselyn , Cao Minwei , Dave Ronak , Tanna Nicole , D’Armiento Jeanine M. , Farber Donna L.
Published: January 2018

Asthma is a chronic inflammatory disease mediated by allergen-specific CD4 T cells that promote lung inflammation through recruitment of cellular effectors into the lung. A subset of lung T cells can persist as tissue-resident memory T cells (TRMs) following infection and allergen induction, although the generation and role of TRM in asthma persistence and pathogenesis remain unclear. In this study, we used a mouse model of chronic exposure to intranasal house dust mite (HDM) extract to dissect how lung TRMs are generated and function in the persistence and pathogenesis of allergic airway disease. We demonstrate that both CD4+ and CD8+ T cells infiltrate into the lung tissue during acute HDM exposure; however, only CD4+ TRMs, and not CD8+ TRMs, persist long term following cessation of HDM administration. Lung CD4+ TRMs are localized around airways and are rapidly reactivated upon allergen re-exposure accompanied by the rapid induction of airway hyperresponsiveness independent of circulating T cells. Lung CD4+ TRM activation to HDM challenge is also accompanied by increased recruitment and activation of dendritic cells in the lungs. Our results indicate that lung CD4+ TRMs can perpetuate allergen-specific sensitization and direct early inflammatory signals that promote rapid lung pathology, suggesting that targeting lung CD4+ TRMs could have therapeutic benefit in alleviating recurrent asthma episodes.
Studies in Small Scale Data: Three Case Studies on Describing Individuals’ Spatial Behaviour in Cities
Authors: Widder Lynnette , Braden Jessie , Ko Joy , Steinfeld Kyle
Published: January 2018

Big Data has been effectively mined to understand behavioural patterns in cities and to map large-scale trends predicated upon the repeated actions of many aggregated individuals. While acknowledging the vital role that this work has played in harnessing the Urban Internet of Things as a means to ensure efficient and sustainable urban systems, our work seeks to recover a scale of behavioural research associated with earlier, empirical studies on urban networks. UrbanIOT data expands the depth and precision of intimate behavioural analysis; small-scale analysis lends insight into important anomalies not explained by large-scale trends. The three case studies at stake here combined empirical journaling with data from mobile devices, tracking both automatically and through user reporting. Each produced diverse information and visualizations for describing the interaction of individual citizens, resources and urban systems. These are: a description of behaviours relative to food stores and shopping habits in New York City, US; a description of the correlation between mobility and food waste likelihood in Providence, RI, US; and a study of mobility patterns and personal choices in Copenhagen, DK.
On application of asymmetric Kan-like exact equilibria to the Earth magnetotail modeling
Authors: Korovinskiy Daniil B. , Kubyshkina Darya I. , Semenov Vladimir S. , Kubyshkina Marina V. , Erkaev Nikolai V. , Kiehas Stefan A.
Published: January 2018

Abstract. A new class of solutions of the Vlasov-Maxwell equations is developed by means of generalization of the well-known Harris-Fadeev-Kan-Manankova family of exact two-dimensional equilibria. The new model reproduces the current sheet bending and shifting in the vertical plane, arising from the Earth dipole tilting and the solar wind non-radial propagation. The generalized model allows magnetic configurations with equatorial magnetic field decreasing in tailward direction as slow as 1/x, contrary to the original Kan model (1/x3); magnetic configurations with a single X-point are also available. The analytical solution is compared with the empirical T96 model in terms of the magnetic flux tube volume. It is found that parameters of the analytical model may be adjusted to fit a wide range of realistic current sheets. The best agreement between analytical and empirical models is obtained for the midtail at distances beyond 10–15 RE at high levels of magnetospheric activity.
Cylindroporella sugdeni Elliott, 1957, an Early Cretaceous Middle Eastern Dasycladalean alga – a revision
Authors: Granier Bruno R. C.
Published: January 2018

Abstract. The type material of Cylindroporella sugdeni Elliott, 1957, is revised. The total lack of sterile laterals and consequently the absence of the diagnostic feature of the genus Cylindroporella, i.e., the alternation of sterile and fertile laterals within the same whorl, leads to its exclusion from the genus Cylindroporella Johnson, 1954, and to its ascription to the genus Holosporella Pia, 1930. Recent stratigraphic investigations suggest that the stratum typicum originally reported as Early Cretaceous in age is more precisely Hauterivian or possibly Early Barremian in age.
CARACTERIZAÇÃO MORFOMÉTRICA DA BACIA HIDROGRÁFICA DO RIBEIRÃO SANTO ANTÔNIO - GO
Authors: Batista Daiane Ferreira , Cabral João Batista Pereira , Rocha Thiago , Barbosa Gustavo Rodrigues
Published: January 2018

O conhecimento dos aspectos morfométricos de uma bacia hidrográfica é indispensável para o planejamento do uso e ocupação das terras. O presente trabalho teve como objetivo principal realizar a caracterização morfométrica da bacia hidrográfica do Ribeirão Santo Antônio – GO, cujo estudo justifica-se devido à grande importância desse ribeirão para a cidade de Iporá e municípios vizinhos, por ser o principal abastecedor de água. A metodologia de análise deu-se por meio da avaliação de parâmetros físicos e morfométricos. Como resultado da pesquisa, destacam-se os valores baixos da Densidade da drenagem (1,30 km²), Relação do relevo (67,34), entre outros, afirmando ser uma bacia que apresenta suscetibilidade média a enchentes e que necessita de planejamento adequado para utilização das terras em atividades antrópicas.
TECHNOLOGIES FOR WASTEWATER TREATMENT FROM THE FISH PROCESSING INDUSTRY: REUSE ALTERNATIVES
Authors: Ribeiro Fábio Henrique de Melo , Naval Liliana Pena
Published: January 2018

For the fish processing industry, the treatment proposal for effluentsencounters some difficulties, such as high concentration of organic matter andsolids in suspension, and lack of uniformity in the composition. Consideringthis problem, the objective was to evaluate the removal efficiency fordifferent effluent treatment technologies of the mentioned industry andthe possibility of reuse. In order to do so performed a survey of effluenttreatment systems, verifying the removal rate for pH, total suspended solids(TSS mgL-1), biochemical oxygen demand BOD (mgL-1), chemical oxygendemand COD mgL-1), total nitrogen TN (mgL-1), total phosphorus TP (mgL-1)and oils and greases (mgL-1). The concentrations found were compared tothe limit values imposed by the standards for industrial reuse. As a result, ithas been found that the combination of multiple processes, using advancedtreatment techniques, is appropriate, especially where the purpose is toreuse and/or recycle.
“People of Allada, This Is Our Return”: Indexicality, Multiple Temporalities, and Resonance in the Music of the Gangbé Brass Band of Benin
Authors: Politz Sarah
Published: January 2018

The Gangbé Brass Band song “Alladanou” makes specific historical, linguistic, and musical references to Benin’s precolonial, colonial, and postindependence histories. I use these references as a point of departure in exploring the relationship of the song to the royal court style of adjògàn. I consider how the Cameroonian political theorist Achille Mbembe’s framework of multiple temporalities illuminates the historical flexibility at play in Gangbé’s album Togbé. I conclude by proposing an analytical framework for analyzing “Alladanou” that proceeds from an interest in audience, relationality, the Fon concept of gbè (voice or sound), and resonance.

La chanson du Gangbé Brass Band “Alladanou” fait certains références historiques, linguistiques, et musicales aux histoires précoloniales, coloniales, et de la postindépendence du Bénin. J’utilise ces références comme point du depart pour explorer la relation de la chanson au style du cour royal de l’adjògàn. Je considère comment les idées du theorien politique camerounais Achille Mbembe illuminent la flexibilité historique en jeu dans l’album Togbé de Gangbé. Je conclus en proposant un cadre analytique pour l’analyse de “Alladanou” qui procède d’un intérět à la publique, à la relationnalité, au concept Fon du gbè (la voix ou le son), et à la resonance.
La mesure des précaires
Authors: Tasset Cyprien
Published: January 2018

La notion de précarité occupe une place importante dans la sociologie contemporaine. Mais elle est divisée, aussi bien du point de vue des approches sociologiques que des matrices politiques qui la visent. Pour clarifier ces différences de perspectives, nous revenons, de façon approfondie et en accordant une attention particulière aux différents rapports à la quantification, sur les modes de problématisation qui, à la fin des années 1970, ont investi le nom « précaires ». Premièrement, les sciences sociales du travail s’alarment d’un renouvellement des segmentations juridiques de la condition salariale, dans des termes qui entraînent une tension entre juridisme et étude de la pauvreté. Deuxièmement, des sociologues ont rejoint des experts plus proches d’instances de pouvoir dans une discussion à propos de la signification contestataire des usages « marginaux » de l’emploi précaire. Troisièmement, des théoriciens d’extrême gauche ont tenté de reporter sur « les précaires » le rôle de classe révolutionnaire, inaugurant une série de tentatives de mobilisation. Nous souhaitons faire ressortir l’hétérogénéité des types de connaissance ainsi que des perspectives politiques qui portent sur « les précaires ».
Siegfried Kracauer, sociologue de la culture
Authors: Schmidt-Lux Thomas , Thériault Barbara
Published: January 2018

Alors que, de nos jours, c’est à un critique et un théoricien du cinéma que l’on associe le plus souvent Siegfried Kracauer, nous traçons ici les contours de son oeuvre au regard de sa pertinence pour la sociologie de la culture. Nous concentrant sur ses écrits journalistiques, nous nous intéressons au rôle qu’y joue l’observation et à la place qu’y occupent l’espace et le « concret », à l’écriture sociologique, à la lecture du monde moderne, à la posture des intellectuels et au rapport non dogmatique de l’auteur au politique et à la théorie. Enfin, nous nous interrogeons sur l’apport que représentent ses écrits pour une sociologie qui se veut exigeante et empirique, tout en se présentant comme divertissante et sans formalisme.
Optimizing taxonomic classification of marker gene amplicon sequences
Authors: Bokulich Nicholas A , Kaehler Benjamin D , Rideout Jai Ram , Dillon Matthew , Bolyen Evan , Knight Rob , Huttley Gavin A. , Caporaso J. Gregory
Published: January 2018

Background: Taxonomic classification of marker-gene sequences is an important step in microbiome analysis.

Results: We present q2-feature-classifier ( https://github.com/qiime2/q2-feature-classifier ), a QIIME 2 plugin containing several novel machine-learning and alignment-based taxonomy classifiers that meet or exceed the accuracy of existing methods for marker-gene amplicon sequence classification. We evaluated and optimized several commonly used taxonomic classification methods (RDP, BLAST, UCLUST) and several new methods (a scikit-learn naive Bayes machine-learning classifier, and alignment-based taxonomy consensus methods of VSEARCH, BLAST+, and SortMeRNA) for classification of marker-gene amplicon sequence data.

Conclusions: Our results illustrate the importance of parameter tuning for optimizing classifier performance, and we make recommendations regarding parameter choices for a range of standard operating conditions. q2-feature-classifier and our evaluation framework, tax-credit, are both free, open-source, BSD-licensed packages available on GitHub.
Self‐Doping Fullerene Electrolyte‐Based Electron Transport Layer for All‐Room‐Temperature‐Processed High‐Performance Flexible Polymer Solar Cells
Authors: Zhang Jingwen , Xue Rongming , Xu Guiying , Chen Weijie , Bian Guo‐Qing , Wei Changan , Li Yaowen , Li Yongfang
Published: January 2018

To achieve high‐performance large‐area flexible polymer solar cells (PSCs), one of the challenges is to develop new interface materials that possess a thermal‐annealing‐free process and thickness‐insensitive photovoltaic properties. Here, an n‐type self‐doping fullerene electrolyte, named PCBB‐3N‐3I, is developed as electron transporting layer (ETL) for the application in PSCs. PCBB‐3N‐3I ETL can be processed at room temperature, and shows excellent orthogonal solvent processability, substantially improved conductivity, and appropriate energy levels. PCBB‐3N‐3I ETL also functions as light‐harvesting acceptor in a bilayer solar cell, contributing to the overall device performance. As a result, the PCBB‐3N‐3I ETL‐based inverted PSCs with a PTB7‐Th:PC71BM photoactive layer demonstrate an enhanced power conversion efficiency (PCE) of 10.62% for rigid and 10.04% for flexible devices. Moreover, the device avoids a thermal annealing process and the photovoltaic properties are insensitive to the thickness of PCBB‐3N‐3I ETL, yielding a PCE of 9.32% for the device with thick PCBB‐3N‐3I ETL (61 nm). To the best of one's knowledge, the above performance yields the highest efficiencies for the flexible PSCs and thick ETL‐based PSCs reported so far. Importantly, the flexible PSCs with PCBB‐3N‐3I ETL also show robust bending durability that could pave the way for the future development of high‐performance flexible solar cells.
Energy Landscape of Vertically Anisotropic Polymer Blend Films toward Highly Efficient Polymer Light‐Emitting Diodes (PLEDs)
Authors: Hassan Muhammad Umair , Liu Yee‐Chen , Yetisen Ali K. , Butt Haider , Friend Richard Henry
Published: January 2018

A blend of two hole‐dominant polymers is created and used as the light emissive layer in light‐emitting diodes to achieve high luminous efficiency up to 22 cd A−1. The polymer blend F81−xSYx is based on poly(9,9‐dioctylfluorene) (F8) and poly(para‐phenylene vinylene) derivative superyellow (SY). The blend system exhibits a preferential vertical concentration distribution. The resulting energy landscape modifies the overall charge transport behavior of the blend emissive layer. The large difference between the highest unoccupied molecular orbital levels of F8 (5.8 eV) and SY (5.3 eV) introduces hole traps at SY sites within the F8 polymer matrix. This slows down the hole mobility and facilitates a balance between the transport behavior of both the charge carriers. The balance due to such energy landscape facilitates efficient formation of excitons within the emission zone well away from the cathode and minimizes the surface quenching effects. By bringing the light‐emission zone in the middle of the F81−xSYx film, the bulk of the film is exploited for the light emission. Due to the charge trapping nature of SY molecules in F8 matrix and pushing the emission zone in the center, the radiative recombination rate also increases, resulting in excellent device performance.
Molecular Consideration for Small Molecular Acceptors Based on Ladder‐Type Dipyran: Influences of O‐Functionalization and π‐Bridges
Authors: Yang Lisi , Li Miao , Song Jinsheng , Zhou Yuanyuan , Bo Zhishan , Wang Hua
Published: January 2018

Molecular engineering of nonfullerene acceptors (NFAs) plays a vital role in the development of organic photovoltaics. Oxygen as an electron donating atom is incorporated into the NFA system as alkoxyl forms at central, terminal, or central conjugated moieties due to the tunability at structural conformation, solubility, electron donating ability, absorption, energy levels, etc. In this work, a novel dipyran‐based ladder‐type building block (Ph‐DTDP), which possesses two oxygen atoms in the conjugated skeleton, is designed and facilely synthesized. It is applied as the donor core for the acceptor–donor–acceptor‐type NFA design and such functionalized‐O efficiently enhances the electron donating ability, lowers the band gap, redshifts and extends the absorption spectra. In addition, the π‐bridge effects are considered as well. Photovoltaic performances are systematically investigated and a high power conversion efficiency of 9.21% can be afforded with an energy loss of 0.57 eV. Meanwhile, the morphologies as well as the carrier mobilities of the blend films are studied to assist further understanding of the structure–property relationships. Overall, the study in this work provides a new promising ladder‐type dipyran building block and brings in a novel way to use oxygen in NFA molecular structure design.
Rational Molecular Design for Deep‐Blue Thermally Activated Delayed Fluorescence Emitters
Authors: Chan Chin‐Yiu , Cui Lin‐Song , Kim Jong Uk , Nakanotani Hajime , Adachi Chihaya
Published: January 2018

By simple modification of the functional groups on the donor unit, the thermally activated delayed fluorescence (TADF) properties of emitters can easily be manipulated. A series of deep blue to blue emissive TADF derivatives is developed, capable of deep‐blue emissions from 403 to 460 nm in toluene. Deep‐blue organic light‐emitting diodes (OLEDs) based on this series of TADF emitters are fabricated, resulting in an electroluminescence peak at 428 nm and a high external quantum efficiency of up to 10.3%. One deep‐blue OLED has achieved the commission internationale de l'eclairage (CIE) coordinates of (0.156, 0.063), which is among the best reported TADF performances for deep‐blue OLEDs with CIEy < 0.07.
IR Spectrum and Structure of Protonated Monosilanol: Dative Bonding between Water and the Silylium Ion
Authors: George Martin Andreas Robert , Truong Nguyen Xuan , Savoca Marco , Dopfer Otto
Published: January 2018

We report the spectroscopic characterization of protonated monosilanol (SiH3OH2+) isolated in the gas phase, thus providing the first experimental determination of the structure and bonding of a member of the elusive silanol family. The SiH3OH2+ ion is generated in a silane/water plasma expansion, and its structure is derived from the IR photodissociation (IRPD) spectrum of its Ar cluster measured in a tandem mass spectrometer. The chemical bonding in SiH3OH2+ is analyzed by density functional theory (DFT) calculations, providing detailed insight into the nature of the dative H3Si+‐OH2 bond. Comparison with protonated methanol illustrates the differences in bonding between carbon and silicon, which are mainly related to their different electronegativity and the different energy of the vacant valence pz orbital of SiH3+ and CH3+.
Tuning the Adsorption Energy of Methanol Molecules Along Ni‐N‐Doped Carbon Phase Boundaries by the Mott–Schottky Effect for Gas‐Phase Methanol Dehydrogenation
Authors: Xue Zhong‐Hua , Han Jing‐Tan , Feng Wei‐Jie , Yu Qiu‐Ying , Li Xin‐Hao , Antonietti Markus , Chen Jie‐Sheng
Published: January 2018

Engineering the adsorption of molecules on active sites is an integral and challenging part for the design of highly efficient transition‐metal‐based catalysts for methanol dehydrogenation. A Mott–Schottky catalyst composed of Ni nanoparticles and tailorable nitrogen‐doped carbon‐foam (Ni/NCF) and thus tunable adsorption energy is presented for highly efficient and selective dehydrogenation of gas‐phase methanol to hydrogen and CO even under relatively high weight hourly space velocities (WHSV). Both theoretical and experimental results reveal the key role of the rectifying contact at the Ni/NCF boundaries in tailoring the electron density of Ni species and enhancing the absorption energies of methanol molecules, which leads to a remarkably high turnover frequency (TOF) value (356 mol methanol mol−1 Ni h−1 at 350 °C), outpacing previously reported bench‐marked transition‐metal catalysts 10‐fold.
Coordination modes of multidentate azodye ligand derived from 4,4′‐methylenedianiline towards some transition metal ions: Synthesis, spectral characterization, thermal investigation and biological activity
Authors: Abouel‐Enein Saeyda A. , Emam Sanaa M. , Monir Eman
Published: January 2018

Nine new azodye metal complexes of Mn(II), Co(II), Ni(II), Cu(II), Cr(III), Fe(III), Ru(III), Hf(IV) and Zr(IV) ions have been prepared via the reaction of 5,5′‐((1E,1′E)‐(methylenebis(1,4‐phenylene))bis(diazene‐2,1‐diyl))bis(6‐hydroxy‐2‐thioxo‐2,3‐dihydropyrimidin‐4(5H)‐one) (H4L) with the corresponding metal salts affording sandwich (1 L:1 M), mononuclear (2 L:1 M), binuclear (1 L,2 M) and tetranuclear (1 L,4 M) complexes. Elemental analyses, spectral methods, magnetic moment measurements and thermal studies were utilized to confirm the mode of bonding and geometrical structure for the ligand and its metal complexes. Infrared spectral data show that the H4L ligand chelates with some metal ions in keto–enol–thione or keto–thione manner. It behaves in a neutral/dibasic tetradentate fashion in sandwich and binuclear complexes. Also, it acts as a neutral bidentate moiety in the Cr(III) complex. The spectra reveal that azo group participates in chelation in all complexes. Octahedral geometry was suggested for all chelates but the Cu(II) complex with square planar geometry. The thermal stability and decomposition of the compounds were studied, the data showing that the thermal decomposition ended with metal or metal oxide mixed with carbon as final product. The electron spin resonance spectrum of the Cu(II) complex demonstrates that the free electron is located in the (
) orbital. Measurements of biological activity against human cell lines Hep‐G2 and MCF‐7 reveal that the Cu(II) complex has a higher cytotoxicity in comparison to the free ligand and other metal complexes, with IC50 values of 6.10 and 5.2 μg ml−1, respectively, while the ligand has anti‐tumour activity relative to some of the investigated metal complexes.
Synthesis of crab type Aminomethyldiphosphine‐Oxovanadium(IV) complexes supported on magnetic Nano particles: Selective and recoverable catalysts in vitamin K3 synthesis
Authors: Uruş Serhan , Çaylar Mahmut , Koçer Ferudun
Published: January 2018

Nano Fe3O4 particles were obtained in microvawe oven using closed system. Oxovanadium(IV) complexes of Fe3O4@SiO2@(aminomethylphosphine) type ligands were synthesized and characterized using SEM, EDX, TEM, UV‐Visible, XRD, FT‐IR and TG/DTA techniques. Catalytic properties of the synthesized pincer type oxovanadium(IV)‐aminomethylphosphine complexes supported on magnetic nano structure were investigated in the synthesis of 2‐methyl‐1, 4‐naphthoquinone (Vitamin K3, menadione, 2MNQ) from 2‐methyl naphthalene (2MN) in hydrogen peroxide, acetic acid and sulfuric acid. Magnetic‐nano particle supported oxovanadium(IV)‐aminomethylphosphine type complexes were very efficient catalysts with the 51.36‐55.20 % selectivities in conversions of 89.78‐95.01 %. Besides, the hetergeneous complexes were very active in five cycling tests on avarage evaluated in the reusability.
Multispectroscopic DNA interaction and Docking studies
Authors: Shekhar B. , Vasantha P. , Sathish Kumar B. , Anantha Lakshmi P.V.
Published: January 2018

Two new water soluble oxovanadium(IV) complexes with formulae Na[VO(his)(met)SO4] (1) and Na[VO(gly)(met)SO4] (2), (gly=glycine his=histidine, and met=metformin) were synthesized and characterized by LCMS, UV‐Visible absorption, infrared spectra, magnetic moment, elemental analysis, thermal analysis and electronic spectral studies. The metal center was found in an octahedral geometry. DNA binding interaction of these complexes with CT DNA has been explored by UV‐Visible absorption, fluorescence, viscosity measurements and cleavage studies. Finally the binding of the complexes with CT‐DNA could be surface binding, mainly in the groove binding. The complexes were docked in to B‐DNA sequence, 5’(D*AP*CP*CP*GP*AP*CP*GP*TP*CP*GP*GP*T)‐3’ retrieved from protein data bank (PDB ID: 423D), using Discovery Studio 2.1 software.
Structural diversity and tie strength in the purchase of a social networking app
Authors: Shmargad Yotam
Published: January 2018

Although people increasingly rely on online services to maintain their relationships, we know relatively little about what drives their use. To address this, I analyze data from a social networking site that started charging its users for an app that populates their e‐mail address books with updated contact information. I find that purchase rates of the app were higher for users with large, structurally diverse networks – which contain several distinct social groups. Moreover, personal ties (i.e., family members and friends) increased purchase rates more than professional ties. I attribute the first effect to the difficulty of obtaining information about a large, diverse social network, which the app reduces, and the second effect to the regularity with which people use information about their personal ties.
Synthesis of novel Dy3+ activated Ba2CaZn2Si6O17 phosphors for white light‐emitting diodes
Authors: Annadurai G. , Masilla Moses Kennedy S. , Sivakumar V.
Published: January 2018

Dysprosium ion (Dy3+) activated Ba2CaZn2Si6O17 phosphors were synthesized using high temperature solid‐state reaction method. Powder X‐ray diffraction (PXRD) analysis confirmed the phase formation of the as‐prepared phosphors. Scanning electron microscopy (SEM) analysis disclosed an agglomeration of particles with an irregular morphology. Under 350 nm excitation, the emission spectrum of Dy3+ ions showed bands at 481 nm (blue), 577 nm (yellow) and 674 nm (red). The influence of the Dy3+ concentration on its emission intensity was investigated. The optimum concentration of Dy3+ ions in the Ba2CaZn2Si6O17:Dy3+ phosphors were found to be x = 0.06. The critical energy transfer distance was calculated. The fluorescence lifetime was also determined for Ba2CaZn2Si6O17:0.06Dy3+. The Commission International deI’Eclairage (CIE) chromaticity coordinates of the phosphor were calculated to be x = 0.304, y = 0.382. The activation energy for the thermal quenching was calculated to be 0.168 eV. These results indicated that the Ba2CaZn2Si6O17:Dy3+ phosphor might be a potential candidate for near ultraviolet (NUV)‐based white light‐emitting diodes.
2,2′‐Bipyridine Equipped with a Disulfide/Dithiol Switch for Coupled Two‐Electron and Two‐Proton Transfer
Authors: Cattaneo Mauricio , Schiewer Christine E. , Schober Anne , Dechert Sebastian , Siewert Inke , Meyer Franc
Published: January 2018

[1,2]Dithiino[4,3‐b:5,6‐b′]dipyridine (1) and its protonated open form 3,3′‐dithiol‐2,2′‐bipyridine (2) were synthesised and their interconversion investigated. The X‐ray structure of 2 revealed an anti orientation of the two pyridine units and a zwitterionic form. In depth electrochemical studies in combination with DFT calculations lead to a comprehensive picture of the redox chemistry of 1 in the absence and presence of protons. Initial one‐electron reduction at E1=−1.20 V results in the formation of the radical anion 1red with much elongated S−S bond, which readily undergoes further reduction at E2=−1.38 V. Water triggers a potential inversion (E≥−1.13 V for the second reduction) as the radical anion 1red is protonated at its basic N atom. DFT studies revealed that S−S bond breaking and twisting of the pyridine units generally occurs after the second reduction step, whereas the potential inversion induced by protonation is a result of charge compensation. The CV data were simulated to derive rate constants for the individual chemical and electrochemical reactions for both scenarios in the absence and presence of protons.