bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chinese immigrant students in Hong Kong: Exploring performance and influences on their civic learning
Authors: Zhu Jinxin , Kennedy Kerry J. , Mok Magdalena Mo Ching , Halse Christine Margaret 
Published: January 2019

AbstractGuided by the “opportunity–propensity” (O‐P) framework, this study explores how immigrant status might affect students’ civic knowledge through an antecedent factor (socioeconomic status [SES]), opportunity factors (civic learning at school and civic participation at school), and propensity factors (perceived open classroom climate, perceived student–teacher relationship, and perceived importance of conventional citizenship). The data were taken from the International Civic and Citizenship Education Study (ICCS) 2016. The sample comprised 2,544 eighth graders from Hong Kong. Results of two‐level path analysis showed that, at the student level, mainland Chinese immigrant grant students had a higher level of civic knowledge. Although perceived open classroom climate and perceived importance of conventional citizenship were found to be two positive mediators and family SES (via civic learning at school) was a negative mediator, the mediation effects at the student level were quite small. In contrast, quite a large amount of variance was explained at the school level: School‐aggregated immigrant status was positively linked to school‐aggregated civic knowledge and negatively via school‐aggregated students’ family SES via school‐aggregated civic learning.
L‐Proline‐Functionalized Fe3O4 Nanoparticles as an Efficient Nanomagnetic Organocatalyst for Highly Stereoselective One‐Pot Two‐Step Tandem Synthesis of Substituted Cyclopropanes
Authors: Firouzi‐Haji Razieh , Maleki Ali 
Published: January 2019

AbstractIn this study, a series of highly stereoselective polysubstituted cyclopropane derivatives (trans‐2,3‐dihydro‐spiro[2‐aroyl‐3‐aryl‐cyclopropane]1,2‐indene‐1,3‐diones) were synthesized via a one‐pot two‐step tandem reaction starting from phenacyl bromide derivatives, 1,3‐indanedione and aromatic aldehydes in ethanol using 1,4‐diazabicyclo[2.2.2]octane (DABCO) as a co‐catalyst and Fe3O4\SiO2\propyltriethoxysilane\L‐proline as a nanomagnetic organocatalyst. This synthesized nanocatalyst was characterized by Fourier transforms infrared (FT‐IR) spectroscopy, energy dispersive X‐ray (EDX) analysis and scanning electron microscopy (SEM) images to confirm the formation of the nanocomposite. The catalyst can be easily recovered by simple magnetic decantation and their catalytic activity remains unaltered after ten consecutive cycles, making them environmentally‐friendly and widely applicable due to their efficiency, ease of handling and cost effectiveness.
L‐Proline‐Catalyzed One‐Pot Diastereoselective Synthesis of Cyclohexanols from β‐Aryl‐γ‐nitroketones and α,β‐Unsaturated Aldehydes: A New Route to 2,3,4,6‐Tetrasubstituted Phenols
Authors: Yadav Anubha , Srivastava Anvita , Mobin Shaikh M. , Samanta Sampak 
Published: January 2019

AbstractA wide array of densely functionalized cyclohexanol derivatives having five contiguous chiral centers were efficiently achieved in good to high yields with high diastereoselectivities. The double C−C bonds forming reaction proceeds via a domino nitro‐Michael/aldol reaction between several β‐aryl‐substituted‐γ‐nitroketones and a range of β‐aryl‐substituted acroleins as Michael acceptors catalyzed by L‐proline as a naturally available, non‐toxic, cheap organocatalyst. Several important features of this strategy include 100% atom‐economical, high‐efficiency, operational simplicity, and broad functional‐group tolerance. Gratifyingly, one‐pot conversion of cyclohexanols to a novel class of 2,3,4,6‐tetrasubstituted phenols under metal‐free conditions has been demonstrated.
Catalyst‐Free Solid Phase Microwave‐Assisted Synthesis of 1,4‐Dihydropyridine Derivatives and Their Single Crystal Structure Determination
Authors: Maru Minaxi S. , Sudhadevi Antharjanam P. K. , Khan Noor‐ul H. 
Published: January 2019

AbstractCatalyst‐free solid phase Hantzsch synthesis of symmetric 4‐(3‐bromo‐4‐hydroxy‐5‐methoxyphenyl)‐2,6‐dimethyl‐3,5‐dicarbethoxy‐1,4‐dihydropyridine (4 a) and 4‐(3‐bromo‐4‐hydroxy‐5‐methoxyphenyl)‐2,6‐dimethyl‐3,5‐dicarbmethoxy‐(4‐nitrophenyl)‐1,4‐dihydropyridine (4 b) was carried out at 400 W under the microwave irradiation. The molecular crystal of both compounds were developed in a suitable solvents and characterized by X‐ray crystallographic method along with other spectroscopic techniques (viz., FT‐IR, 1H & 13C NMR, LC–MS, and elemental analysis). Single crystal structures of both compounds crystallizes in the orthorhombic and triclinic crystal systems with Cmc21 and P1 space groups consisting a=13.5755(13) Å, b=9.6755(9) Å, c=17.7625(17) Å, α=72.837(2)°, β=88.273(2)°, γ=75.221(2)° and a=8.9877(14) Å, b=11.1543(17) Å, c=12.2365(19) Å, α=90.00°, β=90.00°, γ=90.00° cell parameters, with 0.150 × 0.150 × 0.100 mm3 and 0.250 × 0.180 × 0.100 mm3 crystal size respectively. The 1,4‐DHP ring of both compounds have adopted a flattened boat‐type conformation and shows one and four intermolecular hydrogen bonds, respectively.
Carbon Monoxide Playing Ping Pong with a Proton: The Movie
Authors: Frank Irmgard 
Published: January 2019

AbstractThe understanding of chemical reactions is strongly facilitated by movies showing the motion of electrons and nuclei with time. Car‐Parrinello molecular dynamics, or more generally ab‐initio molecular dynamics, is the optimal tool for generating such movies. In the present study an example is shown of a proton transfer reaction which nearly consists in nuclear motion only, while normally the shape and motion of the electronic orbitals are the driving motives for chemical reactions. The reaction can be described with a purely classical description of the nuclear motion, a quantum mechanical description with a wave function is needed for the electronic structure only. This is well known for many reactive systems, but can obviously also be the case for proton transfers which are often seen as an exception.
Structural, Spectroscopic, Electronic and Molecular Docking Studies on (11R,12 S)‐16‐Aminotetracyclo[6.6.2.02,7.09,14]hexadeca‐2(7),3,5,9(14),10,12‐hexaen‐15‐ol
Authors: Kaya Serdal , Gökce Halil , El‐Azab Adel S. , Sert Yusuf , Alanazi Mohammed M. , Öztürk Nuri , Al‐Agamy Mohamed H. M. , Abdel‐Aziz Alaa A.‐M. 
Published: January 2019

AbstractMolecular structure analysis, vibrational and electronic spectroscopic studies and thermochemical features of (11R,12 S)‐16‐aminotetracyclo[6.6.2.02,7.09,14]hexadeca‐2(7),3,5,9(14),10,12‐hexaen‐15‐ol were investigated via both theoretical and experimental techniques. Experimental investigations were made by using FT‐IR, Raman, 1H and 13C NMR and UV‐Vis. spectroscopies. To support experimental evidences, molecular electronic structure computations were obtained with the DFT/B3LYP method at the 6–311G++(3d,3p) basis set. 2D and 3D Hirshfeld surfaces studies were performed to understand non‐bonding intermolecular interactions in solid phase crystal packing of the compound. MEP surface analysis was performed to investigate nucleophilic and electrophilic reactive sites of the compound. The highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMO) analyses were theoretically used for determination of electronic transitions corresponding to UV‐Vis. electronic absorption wavelengths. Enzyme‐ligand interactions between the compound with BACE1 (Beta‐Secretase1) inhibitor were determined via molecular docking study.
Fabrication of Semi‐crystalline Film by Hexanoylation on Self‐assembled Chitin Nanofibers
Authors: Kadokawa Jun‐ichi , Kawano Akito , Yamamoto Kazuya 
Published: January 2019

AbstractChitin shows poor solubility and processability because of its high crystallinity. However, nanofibrillation of chitin has attracted much research attention because of its tendency towards effective materialization and functionalization. We have earlier reported that a self‐assembled chitin nanofiber (ChNF) film is obtained from a chitin/1‐allyl‐3‐methylimidazolium bromide (AMIMBr) ion gel by regeneration with methanol, followed by filtration. The film was constructed by high entanglement of ChNFs during the isolation procedure. In this study, we examined the fabrication of a semi‐crystalline chitin film by hexanoylation on ChNFs under dispersion conditions. After the reaction, the resulting chitin hexanoate reformed the film, but showed a reduced nanofiber morphology, the extent of which depended on the degree of substitution. The fusion of amorphous phases among crystalline phases by preferential hexanoylation at ChNF surfaces produced the semi‐crystalline film with flexible property.
Enzyme‐Catalyzed Starch Esterification in Deep Eutectic Solvent
Authors: Deng Xiaonan , Han Xiaozhao , Hu Xianguo , Zheng Shufeng , Liu Kun 
Published: January 2019

AbstractFor the first time the enzymatic esterification of starch in deep eutectic solvent (DES) was reported using DES of choline chloride (ChCl)‐ethylene glycol (EG) as reaction solvent/medium, Novozyme 435 as catalyst, and PEG 400 as phase transfer agent to synthesize starch decanoate, starch laurate, and starch palmitate. The product samples of esterified starches were characterized by FTIR, 1H NMR, GPC, SEM, XRD, and DSC tests. The results showed that, the degrees of substitution were in the range of 0.07‐0.19 and the addition of PEG 400 was helpful to increase the DS. The optimal esterification temperature for DS was 338 K in the range studied. The degradation of starch was found to be minor due to the use of long‐chain fatty acid and relatively low reaction temperatures. The dissolution, gelatinization, esterification, and recrystallization of starch in DES broke the particles into smaller ones and altered the crystal structure of native starch while the aggregation between particles was increased and the degree of crystallinity was decreased for the esterified starch with the length of carbon‐chain in the fatty acids.
The Productivity and Viability of Snake River Sockeye Salmon Hatchery Adults Released into Redfish Lake, Idaho
Authors: Kozfkay Christine C. , Peterson Mike , Sandford Benjamin P. , Johnson Eric L. , Kline Paul 
Published: January 2019

AbstractIn 1991, the Snake River Sockeye Salmon Captive Broodstock Program was initiated to prevent the extinction and preserve the genetic diversity of this evolutionarily significant unit protected by the Endangered Species Act. At the time of listing, the Redfish Lake Sockeye Salmon Oncorhynchus nerka population was considered functionally extinct. One of the recovery strategies entails the release of adults for volitional spawning in Redfish Lake, Idaho, for rebuilding of the natural population. In this paper, we describe the productivity metrics from this strategy. We evaluated eight spawn years to address three primary questions: (1) What metrics for eggs to smolts, smolts per female, and smolt‐to‐adult returns (SARs) result from recent adult releases? (2) How do these metrics compare with historical estimates for Redfish Lake and estimates for other Sockeye Salmon populations throughout the range? and (3) Does the current combination of smolts per female and SARs result in population replacement? Replacement was determined as two adult recruits per female assuming an even sex ratio. We found that the reintroduced adults, despite being derived from a multigenerational captive broodstock, were able to successfully spawn and produce offspring that migrated to the ocean and returned as adults. Smolt abundance, size, and age data suggest that the population is functioning below density dependence. However, increased smolt production did not translate into greater adult returns and this is likely due to out‐of‐basin factors. Productivity metrics were similar to those of the wild population in Redfish Lake during the 1950s and 1960s. However, both current and historic productivity estimates were near the low end of the range for other Sockeye Salmon populations and have not resulted in population replacement. Until freshwater and out‐of‐basin survival can be improved, our data suggest that adult releases will continue to be an important recovery strategy to prevent cohort collapse and to rebuild naturally spawning populations.
Progressive collapse performance analysis of precast reinforced concrete structures
Authors: Feng De‐Cheng , Wang Zhun , Wu Gang 
Published: January 2019

SummaryIn this paper, the progressive collapse performance analysis of precast reinforced concrete (RC) structures is performed. A numerical simulation framework for precast RC structures is developed on the basis of the OpenSEES software, where the fiber frame element is used for beam and column type members and Joint2D element is used for the beam‐to‐column connections. The conjugated material models are then introduced, and a min–max failure criterion is imposed on the original models to reflect the steel fracture and concrete crushing when the structure is undergoing progressive collapse. In addition, to overcome the computational difficulties arisen from progressive collapse behavior, two enhanced nonlinear solutions , that is, the consistent quasi‐Newton algorithm and the explicit KR‐α algorithm, are employed, respectively, for static and dynamic analysis. A 10‐storey prototype precast RC structures is designed to verify the developed numerical framework, and the progressive collapse resisting mechanism of the structures is investigated through both static pushdown analysis and dynamic column‐removal analysis. Finally, influences of some typical parameters in precast RC structures on their progressive collapse performance are studied.
Creation of gene pools with amplified fragment length polymorphis markers for development of winter oilseed rape (Brassica napus L.) hybrid cultivars
Authors: Liersch Alina , Bocianowski Jan , Popławska Wiesława , Szała Laurencja , Sosnowska Katarzyna , Cegielska-Taras Teresa , Nowosad Kamila , Matuszczak Marcin , Bartkowiak-Broda Iwona 
Published: January 2019

AbstractThe genetic diversity of two winter oilseed rape (Brassica napus L.) collections was investigated using amplified fragment length polymorphism marker technology. The first collection of 78 genotypes was analyzed using 11 primer-enzyme combinations and PCR products were resolved by 13.35% denaturing polyacrylamide gels. The second collection was investigated using seven fluorescent-labeled AFLP primer combinations and PCR products were separated using capillary electrophoresis. A total of 262 polymorphic AFLP markers were obtained for the first collection and 423 polymorphic markers for the second. On the basis of all markers, principal component analysis was performed for both collections separately. The unweighted pair group method with arithmetic method based on the coefficient of dissimilarity separated the genotypes in collection 1 into two clusters and those in the second collection into three distinct clusters. Resynthesized lines formed a cluster that was clearly distinct from 42 winter oilseed rape parental lines in the cytoplasmic male sterility ogura system. Analysis of molecular variance showed that 79% and 81% of the detected variation was found to be within the groups (in the two collections, respectively), while the variation between groups contributed, respectively, to only 21% and 19% of the variance. Our results indicate that AFLP technology can be useful for the creation of a gene pool of parental components of winter oilseed rape hybrid cultivars. Additionally, de novo resynthesized Brassica napus lines provide a significant opportunity for enrichment of the gene pool of winter rapeseed.
The nonclassical mereology of olfactory experiences
Authors: Skrzypulec Błażej 
Published: January 2019

AbstractWhile there is a growing philosophical interest in analysing olfactory experiences, the mereological structure of odours considered in respect of how they are perceptually experienced has not yet been extensively investigated. The paper argues that odours are perceptually experienced as having a mereological structure, but this structure is significantly different from the spatial mereological structure of visually experienced objects. Most importantly, in the case of the olfactory part-structure, the classical weak supplementation principle is not satisfied. This thesis is justified by referring to empirical results in olfactory science concerning the human ability to identify components in complex olfactory stimuli. Further, it is shown how differences between olfactory and visual mereologies may arise from the way in which these modalities represent space.
A Cohort Comparison of Lifespan After Age 100 in Denmark and Sweden: Are Only the Oldest Getting Older?
Authors: Medford Anthony , Christensen Kaare , Skytthe Axel , Vaupel James W. 
Published: January 2019

AbstractAlthough Denmark and Sweden have close cultural and historical ties, lifespans for Danes have generally been lower than those of Swedes. Recent improvements in Danish mortality after a period of stagnation have led to the suspicion that there may be positive trends at the very high ages at death within that population and that these trends could be quite different from those observed in Sweden. Although the mean ages at death for Danish and Swedish centenarians have been relatively constant at about 102 years for the cohorts born 1870–1904, the oldest-old in Denmark have been getting older, but no evidence has suggested any increase in lifespan for Swedes. Using quantile regression, we show that Danish centenarian lifespans in the 90th percentile have been lengthening, with those in 94th percentile (6 % longest-lived individuals) having a trend that is statistically significant at the 5 % level. We demonstrate that the increase observed is not due to the increasing sizes of birth cohorts and thus must be due to improving survival among this select top tier. We postulate that this super-select group in Denmark is best able to take advantage of the factors driving mortality reduction, whereas the majority of centenarians are not.
Structural connectivity centrality changes mark the path toward Alzheimer's disease
Authors: Peraza Luis R. , Díaz‐Parra Antonio , Kennion Oliver , Moratal David , Taylor John‐Paul , Kaiser Marcus , Bauer Roman ,   Alzheimer's Disease Neuroimaging Initiative
Published: January 2019

AbstractIntroductionThe pathophysiological process of Alzheimer's disease is thought to begin years before clinical decline, with evidence suggesting prion‐like spreading processes of neurofibrillary tangles and amyloid plaques.MethodsUsing diffusion magnetic resonance imaging data from the Alzheimer's Disease Neuroimaging Initiative database, we first identified relevant features for dementia diagnosis. We then created dynamic models with the Nathan Kline Institute‐Rockland Sample database to estimate the earliest detectable stage associated with dementia in the simulated disease progression.ResultsA classifier based on centrality measures provides informative predictions. Strength and closeness centralities are the most discriminative features, which are associated with the medial temporal lobe and subcortical regions, together with posterior and occipital brain regions. Our model simulations suggest that changes associated with dementia begin to manifest structurally at early stages.DiscussionOur analyses suggest that diffusion magnetic resonance imaging–based centrality measures can offer a tool for early disease detection before clinical dementia onset.
On critical exponents of ak-Hessian equation in the whole space
Authors: Wang Yun , Lei Yutian 
Published: January 2019

AbstractIn this paper, we study negative classical solutions and stable solutions of the followingk-Hessian equation$$F_k(D^2V) = (-V)^p\quad {\rm in}\;\; R^n$$with radial structure, wheren⩾ 3, 1 <k<n/2 andp> 1. This equation is related to the extremal functions of the Hessian Sobolev inequality on the whole space. Several critical exponents including the Serrin type, the Sobolev type, and the Joseph-Lundgren type, play key roles in studying existence and decay rates. We believe that these critical exponents still come into play to researchk-Hessian equations without radial structure.
AN ALGORITHM TO CONSTRUCT THE LE DIAGRAM ASSOCIATED TO A GRASSMANN NECKLACE
Authors: AGARWALA SUSAMA , FRYER SIÂN 
Published: January 2019

AbstractLe diagrams and Grassmann necklaces both index the collection of positroids in the nonnegative Grassmannian Gr≥0(k, n), but they excel at very different tasks: for example, the dimension of a positroid is easily extracted from its Le diagram, while the list of bases of a positroid is far more easily obtained from its Grassmann necklace. Explicit bijections between the two are, therefore, desirable. An algorithm for turning a Le diagram into a Grassmann necklace already exists; in this note, we give the reverse algorithm.
Kinematics and Manipulability Analysis of a Highly Articulated Soft Robotic Manipulator
Authors: Bamdad Mahdi , Bahri M. Mehdi 
Published: January 2019

SummaryRecently, the idea of applying “jamming” of appropriate media has been exploited for a novel continuum robot design. It is completed by applying vacuum in a robot structure filled with granular media. The backbone deformation and motion are achieved by controlling the fluid pressure. A jammable robotic manipulator does not certainly follow constant curvature during bending, that is, gravitational loads cause section sag. The kinematics describes the deformation of continuum manipulators. This formulation is expected to facilitate additional synthesis and analysis on workspace. This paper presents a Jacobian-based approach to obtain the forward kinematics solution. The proposed kinematic formulation in this paper tries to combine the key advantages of the techniques in constant curvature and variable curvature models. Hence, the deformation of any arbitrary bending is modeled. The workspace synthesis is continued by kinematic analysis, and in this regard, the manipulability measure is computed. This is an important improvement when compared with existing work for this kind of manipulators. It shows how manipulability measure can determine the workspace quality, where usually reachability is used for robot’s capabilities representation. As a result, the forward kinematics and manipulability analysis based on a piecewise-constant-curvature approximation are discussed in the simulation. The simulation has been carried out according to the fabricated experimental robot.
Description, Implementation, and Evaluation of a Generic Design for Tabled CLP
Authors: ARIAS JOAQUÍN , CARRO MANUEL 
Published: January 2019

AbstractLogic programming with tabling and constraints (TCLP, tabled constraint logic programming) has been shown to be more expressive and in some cases more efficient than LP, CLP, or LP + tabling. Previous designs of TCLP systems did not fully use entailment to determine call/answer subsumption and did not provide a simple and well-documented interface to facilitate the integration of constraint solvers in existing tabling systems. We study the role of projection and entailment in the termination, soundness, and completeness of TCLP systems and present the design and an experimental evaluation of Mod TCLP, a framework that eases the integration of additional constraint solvers. Mod TCLP views constraint solvers as clients of the tabling system, which is generic w.r.t. the solver and only requires a clear interface from the latter. We validate our design by integrating four constraint solvers: a previously existing constraint solver for difference constraints, written in C; the standard versions of Holzbaur’s and , written in Prolog; and a new constraint solver for equations over finite lattices. We evaluate the performance of our framework in several benchmarks using the aforementioned solvers. Mod TCLP is developed in Ciao Prolog, a robust, mature, next-generation Prolog system.