bluuebunny/crossref_metadata_2025_split huggingface dataset:
Significations accordées par des jeunes et des enseignants inuit à leur vécu familial, scolaire et communautaire au Nunavik
Authors: Tatiana Garakani  
Published: April 2017

Les familles autochtones ont vécu des transformations et des ruptures profondes à la suite des effets néfastes du colonialisme, des relocalisations forcées et des écoles résidentielles. Malgré de nombreuses initiatives et d’importants progrès, les séquelles perdurent dans les communautés.En nous appuyant sur une recherche participative effectuée au Nunavik, nous examinons comment la famille, la communauté, la langue inuktitut et la culture inuit ainsi que la question de l’identité et la vision de l’avenir sont évoquées dans les propos des élèves et de leurs enseignants inuit. L’étendue de cette recherche, menée sur trois ans, nous a permis d’assurer une présence continue dans l’école et dans la communauté, instaurant ainsi une relation de confiance, en plus de donner le temps nécessaire aux jeunes et aux enseignants de participer et de contribuer à leur rythme et selon leurs préférences.Les élèves interrogés expriment leur sentiment de vivre à la croisée de deux mondes (inuit et non inuit). Ils tentent de trouver un équilibre tout en revendiquant leur langue et leur culture, et partagent les mêmes craintes que les adultes sur l’avenir de leur communauté. De plus, leur incapacité à bien maîtriser l’inuktitut les empêche de développer des liens significatifs avec les aînés. Les enseignants comme les élèves souhaitent retrouver l’implication plus soutenue des familles et de la communauté.
A study of different frequencies of major stratospheric sudden warmings in CMIP5 historical simulations
Authors: Taguchi M. 
Published: April 2017

AbstractClimatological frequency of major stratospheric sudden warmings (MSSWs) during northern winter has been repeatedly investigated using model simulations, but its model‐to‐model differences are relatively unexplained. Using an archive of the Coupled Model Intercomparison Project Phase 5 (CMIP5) historical simulations with 30 models, this study investigates the MSSW frequency of the simulations by building a framework in which the frequency is decomposed into a few factors. Results first demonstrate that the multimodel differences in the MSSW frequency are closely related to the mean and variability of the zonal mean zonal wind in the extratropical stratosphere in each simulation. An important point is that for each simulation, the zonal wind variability is further represented by a combination, or product, of average strength of extreme transient planetary wave forcings from the troposphere and average deceleration response of the polar vortex to an extreme wave forcing of fixed strength. This product can be interpreted and used as a proxy of large‐scale dynamical variability of the polar vortex arising from the planetary wave‐mean flow interaction. It turns out that a large portion of the CMIP5 model simulations underestimate one or both of the factors, leading to underestimations in dynamical variability. This contributes to the general underestimation of MSSW frequency in the simulations. This study proposes that this framework can be used in general to better understand MSSW frequency in different models and climate conditions (e.g., future climate change).
The freezing level in the tropical Andes, Peru: An indicator for present and future glacier extents
Authors: Schauwecker Simone , Rohrer Mario , Huggel Christian , Endries Jason , Montoya Nilton , Neukom Raphael , Perry Baker , Salzmann Nadine , Schwarb Manfred , Suarez Wilson 
Published: April 2017

AbstractAlong with air temperatures, the freezing level height (FLH) has risen over the last decades. The mass balance of tropical glaciers in Peru is highly sensitive to a rise in the FLH, mainly due to a decrease in accumulation and increase of energy for ablation caused by reduced albedo. Knowledge of future changes in the FLH is thus crucial to estimating changes in glacier extents. Since in situ data are scarce at altitudes where glaciers exist (above ~4800 m above sea level (asl)), reliable FLH estimates must be derived from multiple data types. Here we assessed the FLHs and their spatiotemporal variability, as well as the related snow/rain transition in the two largest glacier‐covered regions in Peru by combining data from two climate reanalysis products, Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar Bright Band data, Micro Rain Radar data, and meteorological ground station measurements. The mean annual FLH lies at 4900 and 5010 m asl, for the Cordillera Blanca and Vilcanota, respectively. During the wet season, the FLH in the Cordillera Vilcanota lies ~150 m higher compared to the Cordillera Blanca, which is in line with the higher glacier terminus elevations. Coupled Model Intercomparison Project version 5 (CMIP5) climate model projections reveal that by the end of the 21st century, the FLH will rise by 230 m (±190 m) for Representative Concentration Pathway (RCP) 2.6 and 850 m (±390 m) for RCP8.5. Even under the most optimistic scenario, glaciers may continue shrinking considerably, assuming a close relation between FLH and glacier extents. Under the most pessimistic scenario, glaciers may only remain at the highest summits above approximately 5800 m asl.
Oblique propagation of monsoon gravity waves during the northern hemisphere 2007 summer
Authors: Thurairajah Brentha , Siskind David E. , Bailey Scott M. , Carstens Justin N. , Russell James M. , Mlynczak Martin G. 
Published: April 2017

AbstractWe present a combination of satellite observation and high‐resolution model output to understand monsoon convection as a source of high‐latitude mesospheric gravity waves (GWs). The GWs generated over the Northern Hemisphere (NH) monsoon region during the 2007 summer and the role of the winds in focusing these GWs toward the high‐latitude middle atmosphere are analyzed using the Sounding of the Atmosphere using Broadband Emission Radiometry/Thermosphere Ionosphere Mesosphere Energetics and Dynamics (SABER/TIMED) satellite temperature data and the high‐resolution Navy Operational Global Atmospheric Prediction System‐Advanced Level Physics High Altitude (NOGAPS/ALPHA) model results. In the NH, above the stratosphere, the monsoon GW Momentum Flux (GWMF) exhibits a poleward tilt that follows the slanted structure of the easterly jet. The correlation coefficients (>0.5) between the time series of NH tropical stratospheric GWMF and the global winds also have a slanted structure that coincide with the easterly jet, confirming the modeling theory that stratospheric monsoon GWs are refracted into the summer easterly jet and can reach the high‐latitude mesosphere. Since Polar Mesospheric Clouds (PMCs) are sensitive indicators of changes in the polar summer mesosphere, we compared the time series of tropical stratospheric GWMF to the PMC occurrence frequency (OF) obtained from the Cloud Imaging and Particle Size/Aeronomy of Ice in the Mesosphere satellite data to assess the influence of this wave focusing in the mesosphere. There is a significant positive correlation between the high‐latitude PMC OF and the tropical stratospheric GWMF suggesting a definite influence of monsoon GWs on the high‐latitude mesosphere. The disagreement in correlation at the end of the PMC season is attributed to the enhancement of the quasi 5 day planetary wave dominating over the influence of monsoon GWs on PMCs.
Highly Efficient Curtius Rearrangement Approach for the Synthesis of Unsymmetrical Sulfonimidoyl Ureas
Authors: Zhou Hao , Hong Jianquan , Huang Jiapian , Chen Zhiyuan 
Published: April 2017

AbstractA highly efficient synthesis of unsymmetrical sulfoximine ureas is developed. The reaction unites simple NH‐sulfoximines and acyl azides by a formal Curtius rearrangement as the key step. This reaction could be easily scaled up to gram scale and omits the generation of hazardous byproducts, thus allowing a practical and environmentally benign path for the synthesis of medicinally important sulfonimidoyl unsymmetrical ureas.
Lead‐free Perovskite Materials (NH4)3Sb2IxBr9−x
Authors: Zuo Chuantian , Ding Liming 
Published: April 2017

AbstractA family of perovskite light absorbers (NH4)3Sb2IxBr9−x (0≤x≤9) was prepared. These materials show good solubility in ethanol, a low‐cost, hypotoxic, and environmentally friendly solvent. The light absorption of (NH4)3Sb2IxBr9−x films can be tuned by adjusting I and Br content. The absorption onset for (NH4)3Sb2IxBr9−x films changes from 558 nm to 453 nm as x changes from 9 to 0. (NH4)3Sb2I9 single crystals were prepared, exhibiting a hole mobility of 4.8 cm2 V−1 s−1 and an electron mobility of 12.3 cm2 V−1 s−1. (NH4)3Sb2I9 solar cells gave an open‐circuit voltage of 1.03 V and a power conversion efficiency of 0.51 %.
Mechanistic Insights into Palladium‐Catalyzed Silylation of Aryl Iodides with Hydrosilanes through a DFT Study
Authors: Xu Zheng , Xu Jin‐Zhou , Zhang Jin , Zheng Zhan‐Jiang , Cao Jian , Cui Yu‐Ming , Xu Li‐Wen 
Published: April 2017

AbstractThe catalytic cycles of palladium‐catalyzed silylation of aryl iodides, which are initiated by oxidative addition of hydrosilane or aryl iodide through three different mechanisms characterized by intermediates R3Si−PdII−H (Cycle A), Ar−PdII−I (Cycle B), and PdIV (Cycle C), have been explored in detail by hybrid DFT. Calculations suggest that the chemical selectivity and reactivity of the reaction depend on the ligation state of the catalyst and specific reaction conditions, including feeding order of substrates and the presence of base. For less bulky biligated catalyst, Cycle C is energetically favored over Cycle A, through which the silylation process is slightly favored over the reduction process. Interestingly, for bulky monoligated catalyst, Cycle B is energetically more favored over generally accepted Cycle A, in which the silylation channel is slightly disfavored in comparison to that of the reduction channel. Moreover, the inclusion of base in this channel allows the silylated product become dominant. These findings offer a good explanation for the complex experimental observations. Designing a reaction process that allows the oxidative addition of palladium(0) complex to aryl iodide to occur prior to that with hydrosilane is thus suggested to improve the reactivity and chemoselectivity for the silylated product by encouraging the catalytic cycle to proceed through Cycles B (monoligated Pd0 catalyst) or C (biligated Pd0 catalyst), instead of Cycle A.
President's Page
Authors: Connaway Lynn Silipigni 
Published: April 2017

EDITOR'S SUMMARYASIS&T president Lynn Silipigni Connaway attended the ASIS&T Regional Meeting at OCLC on March 3, 2017. Special Interest Group/Information and Learning Sciences (SIG/ILS) has launched and will have a presence at the 2017 ASIS&T Annual Meeting in Washington, DC, from October 27 to November 1. In order to facilitate international attendees at the meeting, ASIS&T will be offering visa support documents by request. A conference put together by the Asia Pacific, Taiwan and Europe chapters titled “ASIS&T Presentation: Professional Organizations in Career Development” took place at the iConference in Wuhan, China, on March 24. The Board of Directors has approved a new marketing policy. The search for a new ASIS&T executive director continues. Finally, a respected pioneer in the information science field, Dr. Eugene Garfield, passed away in February. A memorial and account of his life can be found in Inside ASIS&T Reminders and on the ASIS&T website.
Consume, Reproduce, Extend and Connect: Sustaining Our Research Lifecycle
Authors: Johnson Richard P. 
Published: April 2017

EDITOR'S SUMMARYScholarly research is at the forefront of innovation, especially with a breadth of new technologies that can enhance the research process. However, in a race for scholars to produce more and more new findings, documentation practices and reproduction of results may be neglected. Lack of validation through reproduction can lead to a general distrust of scholarly research and experiments, but a more generous approach to information sharing could be the answer to this issue. Scholars have connected socially for centuries to share their ideas, and this practice has led to some truly innovative ideas that have shaped our world today. With willing participants sharing their ideas and their research methods, new findings can be reproduced and validated, creating a stronger and more trustworthy community of scholars.
Formation Pathways toward 2‐ and 4‐Methylbenzaldehyde via Sequential Reactions from Acetaldehyde over Hydroxyapatite Catalyst
Authors: Moteki Takahiko , Rowley Andrew T. , Bregante Daniel T. , Flaherty David W. 
Published: April 2017

AbstractCondensation reactions of biomass derived C2 and C4 aldehydes form both ortho‐ and para‐tolualdehydes (2‐MB and 4‐MB, respectively). The complete reaction network and the detailed mechanisms, however, have not been fully described. Here, analysis of the products formed by sequential condensation reactions of acetaldehyde and 2‐butenal suggests that 2‐ and 4‐MB products form via aromatization of 2,4,6‐octatrienal and of highly reactive acyclic intermediate(s) formed via self‐addition of 2‐butenal, respectively. The exact positions at which C−C bonds form between C4 co‐reactants to create 4‐MB products were investigated by using reactant mixtures containing combinations of 2‐butenal, 2‐butenol, and 3‐methyl‐2‐butenal as model reactants. The last two reactants can form products that may be assigned to specific reaction pathways (not distinguishable during self‐addition of 2‐butenal) and also have decreased reactivity at specific carbon atoms. The analysis of the products suggests that 4‐MB species form via 2‐butenal self‐addition by nucleophilic attack of the α‐C to the carbonyl‐C. Additionally, Diels–Alder reactions (between C6 and C2 intermediates) do not contribute in any significant manner to the formation of 4‐MB. These findings complete the description of the reaction network that forms 2‐ and 4‐MB from acetaldehyde on hydroxyapatite.
Kinetic Modeling of an Enzymatic Redox Cascade In Vivo Reveals Bottlenecks Caused by Cofactors
Authors: Milker Sofia , Fink Michael J. , Oberleitner Nikolin , Ressmann Anna K. , Bornscheuer Uwe T. , Mihovilovic Marko D. , Rudroff Florian 
Published: April 2017

AbstractWe describe the development of a kinetic model for the simulation and optimization of an in vivo redox cascade in E. coli in which a combination of an alcohol dehydrogenase, an enoate reductase, and a Baeyer–Villiger monooxygenase is used for the synthesis of lactones. The model was used to estimate the concentrations of active enzyme in the sequential biotransformations to identify bottlenecks together with their reasons and how to overcome them. We estimated adapted Michaelis–Menten parameters from in vitro experiments with isolated enzymes and used these values to simulate the change in the concentrations of intermediates and products during the in vivo cascade reactions. Remarkably, the model indicated that the fastest enzyme was rate‐determining because of the unexpectedly low concentration of the active form, which opens up reversible reaction channels towards byproducts. We also provide substantial experimental evidence that a low intracellular concentration of flavin and nicotinamide cofactors drastically decreased the performance of the in vivo cascade drastically.
Electrospun Nd3+‐Doped LiMn2O4 Nanofibers as High‐Performance Cathode Material for Li‐Ion Capacitors
Authors: Vijayan Shobana , Kirubasankar Balakrishnan , Pazhamalai Parthiban , Solarajan Arun Kumar , Angaiah Subramania 
Published: April 2017

AbstractElectrospun high‐voltage spinel‐typeLiNd0.01Mn1.99O4 nanofibers (LNdMO NFs) were successfully prepared through the electrospinning technique. The thermal behavior of the electrospun precursor fibrous mat was assessed by thermogravimetric/differential thermal analysis. The crystallite structure and phase purity of Nd3+‐doped LiMn2O4 was confirmed by X‐ray diffraction studies. The chemical structure of the electrospun LNdMO NFs was characterized by Raman spectroscopy studies. The morphology of the nanofibers was examined by using field‐emission scanning electron microscopy. A Li‐ion capacitor (LIC) coin cell was fabricated by using high‐voltage insertion LNdMO NFs as the cathode and black pearl carbon as the anode with electrospun PVdF membrane containing 1 M LiNO3 as the separator and electrolyte. The electrochemical performance of the assembled LIC coin cell was characterized by using cyclic voltammetry, galvanostatic charge−discharge and electrochemical impedance spectroscopy. The LIC was capable of operating over wide potential window of 1.6 V with excellent capacitance retention of 86 % even after 2500 continuous galvanostatic charge−discharge cycles at a constant current density of 1 A g−1. Furthermore, LIC delivered an energy density of 17 Wh kg−1 and a power density of 397 W kg−1. Moreover, these results show that Nd3+‐doped LiMn2O4 NFs can be considered a promising electroactive cathode material for LICs.
V2O3 Polycrystalline Nanorod Cathode Materials for Li‐Ion Batteries with Long Cycle Life and High Capacity Retention
Authors: McNulty David , Buckley D. Noel , O'Dwyer Colm 
Published: April 2017

AbstractWe report on the electrochemical performance of V2O3 polycrystalline nanorods (poly‐NRs) as a cathode material for Li‐ion batteries. Poly‐NRs are formed through the thermal treatment of V2O5 nanotubes in a N2 atmosphere. X‐ray and electron diffraction techniques are used to confirm the thermal reduction. Through galvanostatic cycling, we demonstrate that poly‐NRs offer excellent capacity retention over 750 cycles. The capacity retention from the 50th to the 750th cycle was an impressive 94 %, retaining a capacity of approximately 120 mAh g−1 after 750 cycles. The outstanding stability of the nanocrystal‐containing V2O3 poly‐NRs over many cycles demonstrates that vanadium(III) oxide (V2O3) performs very well as a cathode material. Full Li‐ion cells with paired a V2O3 poly‐NR cathode and a pre‐charged Co3O4 inverse opal (IO) conversion mode anode demonstrated high initial capacities and retained a capacity of 153 mAh g−1 after 50 cycles. The capacities achieved with our V2O3 poly‐NRs/Co3O4 IO full cells are comparable to the capacities obtained from the most commonly used cathode materials when cycled in a half‐cell arrangement versus pure Li metal.
Highly Conductive Water‐Based Polymer/Graphene Nanocomposites for Printed Electronics
Authors: Koutsioukis Apostolos , Georgakilas Vasilios , Belessi Vassiliki , Zboril Radek 
Published: April 2017

AbstractThe preparation and characterization of highly conductive carbon inks is described based on nanocomposites that combine a polystyrene‐acrylic resin or water‐soluble polymers with a hydrophilic graphene/carbon nanotube hybrid. The water‐based carbon inks showed high electrical conductivity and could be effectively used in advanced technologies such as gravure printing for printed electronics. Moreover, the conductivity was shown to be increased with a power law of the nanohybrid volume fraction, with an exponent close to that predicted from the percolation theory, indicating a limited impact of the polymer tunneling barrier on the electrical conductivity of such nanocomposites.
An Aminocatalyzed Stereoselective Strategy for the Formal α‐Propargylation of Ketones
Authors: Jurberg Igor D. 
Published: April 2017

AbstractA two‐step reaction sequence is described for the asymmetric formal α‐propargylation of ketones. This approach takes advantage of an aminocatalyzed conjugate addition of ketones to alkylidene isoxazol‐5‐ones, followed by a controlled nitrosative degradation event. The target compounds can be accessed in broad scope, in moderate to good yields, perfect diastereocontrol and good to excellent enantioselectivity.
DFT Studies on Isoprene/Ethylene Copolymerization Catalyzed by Cationic Scandium Complexes Bearing Different Ancillary Ligands
Authors: Hu Xiaojie , Kang Xiaohui , Zhou Guangli , Wang Xingbao , Hou Zhaomin , Luo Yi 
Published: April 2017

AbstractThe isoprene/ethylene copolymerization catalyzed by cationic rare earth metal complexes [(η5‐C5Me5)Sc(CH2SiMe3)]+ (A) had afforded alternating isoprene‐ethylene copolymer with rich 3,4‐polyisoprene microstructures, whereas no isoprene‐ethylene copolymer was observed by using analogous [(PNPPh)Sc(CH2SiMe3)]+ (B) under the same conditions. Theoretical calculations in this work have revealed that, in the case of A, successive 3,4‐insertion of isoprene resulted in a noncovalent interaction between the C = C double bond of penultimate unit and the metal center, suppressing the further insertion of monomers due to higher energy barrier and endergonic character. On the other hand, the ethylene pre‐inserted species with alkyl active site is more suitable for the subsequent kinetically and thermodynamically favorable isoprene insertion and copolymerization is therefore realized. In the case of B, the experimentally observed cis‐1,4‐specific homopolymerization of isoprene was the outcome of both kinetic and thermodynamic control. And, the unfavorable ethylene insertion into the isoprene pre‐inserted species with allyl active site could account for the experimental finding that no isoprene‐ethylene copolymer was obtained. These computational results are expected to provide some hints for the design of rare earth copolymerization catalysts.
Theoretical Simulation of the Vibrationally Resolved UV Absorption Spectrum of Acryloyl Fluoride
Authors: Cheng Yuanyuan , Liu Yajun 
Published: April 2017

AbstractAcryloyl fluoride is an ideal molecule for investigating the phenomenon of hindered internal rotation. In concert with recently acquired high‐resolution UV absorption spectrum of acryloyl fluoride, in this study, the absorption spectra of the s‐trans and s‐cis isomers of acryloyl fluoride were theoretically simulated. The simulated spectra were convoluted by a Gaussian function with displacement, distortion, Franck‐Condon, Herzberg‐Teller, and Duschinsky effects in the framework of the time‐independent model. The statistical vibronic transition analysis reveals the unity of the spectrum transition property, the relevant normal modes, and the primary geometrical variations, enriching the understanding of the experimental observation. The discrepancy between the theoretical and experimental spectra was interpreted clearly.
Das Schülerlabor „Unser Raumschiff Erde“
Authors: van de Sand Markus , Griesbeck Axel , Henneken Heike , Ruschewitz Uwe 
Published: April 2017

AbstractDas Schülerlabor „Unser Raumschiff Erde“ der Universität zu Köln wurde 2010 aus Mitteln der zdi‐Initiative des Landes NRW gegründet. Inhaltlich werden Versuche zu den Themen Sonne, Ökosphäre, Sensoren und Wasser angeboten. Schülerinnen und Schüler der Mittelstufe führen dabei im Klassenverbund zu einem der Oberthemen verschiedene stark interdisziplinär ausgerichtete Versuche in eintägigen Veranstaltungen durch, die von Studierenden des Lehramts betreut werden. Der Oberstufenbereich hingegen richtet sich an besonders interessierte Schülerinnen und Schüler, die im Rahmen von mehrtätigen Ferienkursen anspruchsvolle Versuche durchführen können, die sich an der Forschung des Departments für Chemie und der Fachgruppe Physik orientieren und bewusst über das hinausgehen, was an Schulen experimentell möglich ist. Diese Experimente werden teilweise von Lehramtsstudierenden im Rahmen von Abschlussarbeiten (Bachelor‐, Master‐ und Staatsexamensarbeiten) entwickelt und dann in Kursen mit den Schülerinnen und Schülern zusammen durchgeführt.