bluuebunny/crossref_metadata_2025_split huggingface dataset:
Earth‐Abundant Alkali Iron Phosphates (AFePO4) as Efficient Electrocatalysts for the Oxygen Reduction Reaction in Alkaline Solution
Authors: Murugesan Chinnasamy , Lochab Shubham , Senthilkumar Baskar , Barpanda Prabeer 
Published: November 2017

AbstractWater‐splitting systems are essential for clean energy production. The oxygen reduction reaction (ORR) is a key reaction involved in water splitting, which requires a catalyst. The current work explores the possible application of sodium and potassium iron phosphates (AFePO4, A=Na and K) as electrocatalysts for ORR activity. These earth‐abundant iron phosphates were synthesized by the solution combustion synthesis (SCS) technique by using ascorbic acid both as fuel and reducing agent for Fe. The crystal structure was analyzed by Rietveld refinement. The formation of carbon coating was identified by thermogravimetric analysis and Raman spectroscopy. Electrocatalytic properties of AFePO4 were investigated in alkali electrolytes for the first time by using linear sweep voltammetry with a rotating disk electrode (RDE). The ORR activities of these alkali iron phosphates are comparable to that of the Pt/C system. The Tafel slope and electron transfer number of the alkali iron phosphates were calculated. The ORR activity of NaFePO4 was found to be better than KFePO4 and FePO4. This work demonstrates alkali iron phosphates as alternate cost‐effective, novel electrocatalysts for productive ORR activity in alkaline solution.
Photoswitchable Intramolecular Hydrogen Bonds in 5‐Phenylazopyrimidines Revealed By In Situ Irradiation NMR Spectroscopy
Authors: Procházková Eliška , Čechová Lucie , Kind Jonas , Janeba Zlatko , Thiele Christina M. , Dračínský Martin 
Published: November 2017

AbstractNMR spectroscopy with in situ irradiation uncovered unique photoswitchable intramolecular hydrogen bonds (IMHBs) in 5‐phenylazopyrimidines with two hydrogen bond donors. These compounds form two stable rotamers, each with one IMHB, and the rotamer ratio changes reversibly upon UV or visible light irradiation. Strong substituent dependence of photoinduced structural changes was observed; using suitable substituents, orthogonal photoswitching can be achieved. For example, whereas UV irradiation caused switching between the two rotamers of the trans isomer of a compound with electron‐donating methoxy substituent, visible light enabled to obtain the cis photoisomer. No cis isomer was detected for compounds with electro‐neutral or electron‐accepting substituents, but photoswitching between the two trans isomers was observed. On the other hand, compounds without hydrogen‐bond donors or with one donor only formed stable cis isomers. A mechanism of the photoswitching was proposed by DFT computations.
L'effet des récompenses sur l'état de santé psychologique des travailleurs: les mécanismes sous‐jacents
Authors: Pellerin Sabrina , Cloutier Julie 
Published: November 2017

AbstractThe effort‐reward imbalance (ERI) model in the workplace (Siegrist, ) suggests that inequity of rewards contributes to a degradation of mental health through a process of devaluation. The objective of our study is to test this hypothesis empirically. Data were collected from 659 agents in three call centres located in the province of Quebec. A bootstrap mediation test show that perceived inequity with respect to rewards (recognition, promotion, job security) affects the level of psychological distress through the perception of being valued by the organization. Perceived inequity affects mental health because it signals to workers the extent to which they are valued by their organization. Our correlational study provides evidence of the internal validity of the ERI model. Copyright © 2017 ASAC. Published by John Wiley & Sons, Ltd.
CF2‐Bridged C60 Fullerene Dimers and their Optical Transitions
Authors: Dallas Panagiotis , Zhou Shen , Cornes Stuart , Niwa Hiroyuki , Nakanishi Yusuke , Kino Yasuhiro , Puchtler Tim , Taylor Robert A. , Briggs G. Andrew. D. , Shinohara Hisanori , Porfyrakis Kyriakos 
Published: November 2017

AbstractFullerene dyads bridged with perfluorinated linking groups have been synthesized through a modified arc‐discharge procedure. The addition of Teflon inside an arc‐discharge reactor leads to the formation of dyads, consisting of two C60 fullerenes bridged by CF2 groups. The incorporation of bridging groups containing electronegative atoms lead to different energy levels and to new features in the photoluminescence spectrum. A suppression of the singlet oxygen photosensitization indicated that the radiative decay from singlet‐to‐singlet state is favoured against the intersystem crossing singlet‐to‐triplet transition.
A Zn(II)‐Containing Coordination Polymer: Synthesis, Crystal Structure and pH Fluorescent Sensing
Authors: Wen Shi‐Zheng , Kan Wei‐Qiu , Zhang Li‐Li , He Yuan‐Chun 
Published: November 2017

AbstractIn this work, a Zn(II)‐containing coordination polymer, [Zn2(2,4′‐tmbpt)2(o‐bdc)2]·5H2O (1) [2,4′‐tmbpt = 1‐((1H‐1,2,4‐triazol‐1‐yl)methyl)‐3‐(4‐pyridyl)‐5‐(2‐pyridyl)‐1,2,4‐triazole and o‐H2bdc = 1,2‐benzenedicarboxylic acid] has been synthesized hydrothermally. The structure of the compound has been characterized by single crystal X‐ray crystallography, elemental analysis, infrared spectra, thermogravimetric analysis and powder X‐ray diffraction analysis. Compound 1 features a 2D layer structure formed by the cross‐link of the wave‐like chains and helical chains. Because the uncoordinated nitrogen atoms in compound 1 can bind H+, the luminescent spectra of compound 1 in aqueous solutions of different pH from 1 to 7 have been investigated. The result indicates that this compound can be used as a sensitive and efficient pH fluorescent sensor, which can be further used for the design of molecular logic gate in the narrow pH range of 2–3. The pH response mechanism of compound 1 may be the disturbance of the conjugated system resulting from the protonation of the 2,4′‐tmbpt ligand in the compound, which has been proved by the UV‐vis absorption spectra and density functional theory (DFT) calculation.
Snowflake Like ZnCo2O4‐xF2x/Polypyrrole Composites as High Performance Anode for Lithium Ion Batteries
Authors: Li Guihua , Jin Rencheng , Zhai Qinghe , Zhang Shaohua 
Published: November 2017

AbstractIn this work, we develop a facile solvothermal method, sintering process as well as an in situ chemical polymerization route to efficiently fabricate hierarchical snowflake like ZnCo2O4‐xF2x/polypyrrole composite. According to the electron microscope observations, the formation mechanism is proposed as an aggregation process and anisotropic growth mechanism. In favor of the element doping and the structural advantages, the ZnCo2O4‐xF2x/polypyrrole composites display excellent electrochemical performance including a high reversible capacity, excellent cyclic ability, and good rate behavior. The excellent electrochemical performance is attributed to the synergistic effect of the mesoporous structure, F anions doping and coating of PPy layer, which shortens the diffusion path for the Li+ ions, improves the kinetic process, promotes the electron transfer on the electrode/electrolyte interface and buffers the volume change during Li+ ion insertion/extraction process.
Encapsulation of Barium Ferrite and Reduced Graphene Oxide in poly(o‐toluidine) as a Barrier for Electromagnetic Radiations
Authors: Gairola Preeti , Ohlan Anil , Gairola S. P. , Verma Vivek , Dhawan S. K. , Purohit L. P. 
Published: November 2017

AbstractThe present paper reports the synthesis and characterization of poly (o‐toluidine) (POT) embedded with barium ferrite and reduced graphene oxide. Barium ferrite nanoparticles (BF) were prepared by citrate precursor technique. Synthesis of reduced graphene oxide (RGO) from graphite powder was carried out by improved Hummer's method. Composite of poly (o‐toluidine) with barium ferrite and reduced graphene oxide (POT/BF/RGO) was synthesized by in‐situ polymerization method. The formulation shows total shielding effectiveness of 12.07 dB in the X‐band (8.4‐12.4 GHz) frequency range. Permeability and dielectric parameters have been calculated from the measured scattering parameters (S11, S22, S12, S21) using the Nicolson–Ross–Weir algorithm. The synthesized formulations were characterized using x‐ray diffraction (XRD), scanning electron microscope (SEM), Transmission electron microscopy TEM, Ultraviolet–visible spectroscopy (UV‐Vis) and vibrating sample magnetometer (VSM).
Preparation and Properties of (Ce0.4La0.2Pr0.2Nd0.2)B6 Single‐Crystal by the Optical Float‐Zone Traveling Solvent Technique
Authors: Wang Pan , Zhang Jiuxing , Yang Xinyu , Ning Shuyu , Zhang Jingwen , Wang Yan , Li Zhi 
Published: November 2017

AbstractThe high quality (Ce0.4La0.2Pr0.2Nd0.2)B6 single‐crystal has been successfully prepared by the optical float‐zone traveling solvent technique. The crystal structure and performance of the (Ce0.4La0.2Pr0.2Nd0.2)B6 single‐crystal obtained at different rates are characterized by using XRD, X‐ray single‐crystal diffraction, rotating target X‐ray Diffractometer, X‐ray Laue diffraction, SEM and thermionic emission equipment etc.. The results show that the as‐grown single‐crystal with the uniform composition has a cubic structure with the lattice size of 4.143 Å. The optimal mechanical and thermionic emission properties belong to the (Ce0.4La0.2Pr0.2Nd0.2)B6 single‐crystal prepared at growth rate V = 7 mm/h. The values of 53.3 A/cm2 in the current density at 1873 K under the applied voltage of 4 kV and 29.26 GPa in Vickers hardness indicate that (Ce0.4La0.2Pr0.2Nd0.2)B6 single‐crystal is a promisingly thermionic emission material.
Determination of Nucleation Kinetics of Cephradine in 0.5% Sodium Bisulfate (W/V) Solution
Authors: Sun Hua , Jiang Cuiyuan , Liu Baoshu 
Published: November 2017

AbstractThe metastable zone width of cephradine in a 0.5% sodium bisulfate (W/V) solution was determined at different values of pH and temperatures by using dynamic laser monitoring under atmospheric pressure. As the pH increased, the metastable zone width of cephradine decreased before increasing, with a minimum value at the isoelectric point. The effect of temperature was less pronounced. The induction periods of cephradine in the 0.5% sodium bisulfate (W/V) solution were investigated as a function of the supersaturation ratio. By applying classical homogeneous nucleation theory, we deduced the crystal‐liquid interfacial tension and the following fundamental nucleation parameters: the Gibbs free energy change for the formation of the critical nucleus, the radius of the critical nucleus, and the number of molecules in the critical nucleus.
Optimal joint load balancing and EDCA configuration of IEEE 802.11 wireless hotspots
Authors: Erturk Mehmet Ali , Vollero Luca , Aydin Muhammed Ali 
Published: November 2017

SummaryWireless hotspots, ie, infrastructures composed of several IEEE 802.11 access points (APs), are today the most common solution in providing Internet access to a wide and rapidly changing population of users. According to common device implementation, stations establish associations with APs based on the measured strongest Received Signal Strength Indicator level. This usually leads to an uneven distribution of users to APs, increasing the chances of local network congestion. Load balancing (LB) solutions aim at mitigating this problem controlling the distribution of users. The LB algorithms enforce stations to associate with APs that manage a low number of users and/or that have a low traffic load. Usually, LB solutions do not consider traffic priorities or they assume some a priori quality of service (QoS) configuration for users.In this study, we propose a QoS‐LB solution based on the cell breathing technique with the goal of balancing the load in IEEE 802.11e Enhanced Distributed Channel Access (EDCA) Hotspots. The proposed algorithm explores the space of possible power/EDCA configurations by using a branch and bound approach that reduces the number of analyzed configurations and, hence, the time required to find the global optimal solution. The algorithm has been analytically defined and its performance evaluated through simulations and tests in a real test bed. The results prove that the proposed solution is effective in solving the optimal QoS‐LB configuration problem in WiFi hotspots of average size.
Developmental, genetic, and genomic insights into the evolutionary loss of limbs in snakes
Authors: Leal Francisca , Cohn Martin J. 
Published: November 2017

SummaryThe evolution of snakes involved dramatic modifications to the ancestral lizard body plan. Limb loss and elongation of the trunk are hallmarks of snakes, although convergent evolution of limb‐reduced and trunk‐elongated forms occurred multiple times in snake‐like lizards. Advanced snakes are completely limbless, but intermediate and basal snakes have retained rudiments of hindlimbs and pelvic girdles. Moreover, the snake fossil record indicates that complete legs were re‐acquired at least once, suggesting that the potential for limb development was retained in some limb‐reduced taxa. Recent work has shown that python embryos initiate development of a transitory distal leg skeleton, including a footplate, and that the limb‐specific enhancer of the Sonic hedgehog gene, known as the zone of polarizing activity regulatory sequence (ZRS), underwent gradual degeneration during snake evolution. In this article, we review historical and recent investigations into squamate limblessness, and we discuss how new genomic and functional genetic experiments have improved our understanding of the evolution of limblessness in snakes. Finally, we explore the idea that pleiotropy of cis‐regulatory elements may illuminate the convergent genetic changes that occurred in snake‐like lizards, and we discuss a number of challenges that remain to be addressed in future studies.
Mating status correlates with dorsal brightness in some but not all poison frog populations
Authors: Dreher Corinna E. , Rodríguez Ariel , Cummings Molly E. , Pröhl Heike 
Published: November 2017

AbstractSexual signals are important for intraspecific communication and mate selection, but their evolution may be driven by both natural and sexual selection, and stochastic processes. Strawberry poison frogs (Oophaga pumilio) show strong color divergence among populations, but coloration also varies among individuals of the same population. The importance of coloration for female mate choice has been studied intensely, and sexual selection seems to affect color divergence in strawberry poison frogs. However, the effect of coloration on mating success under field conditions has received very little attention. Furthermore, few studies examined how phenotypic variation among individuals of the same color morph affects mate selection under natural conditions. We measured the spectral reflectance of courting and noncourting individuals and their background substrates in three geographically separated populations. In one population (Sarapiquí, Costa Rica), we found that naturally occurring courting pairs of males and females had significantly brighter dorsal coloration than individual males and females not engaged in courtship interactions. Our field observations suggest that, in the wild, females prefer brighter males while the reason for the higher courtship activity of brighter females remains unclear. Overall our results imply that brightness differences among individuals of the same color morph may actually affect reproductive success in some populations of strawberry poison frogs.
Relative importance of the land‐use composition and intensity for the bird community composition in anthropogenic landscapes
Authors: Pellissier Vincent , Mimet Anne , Fontaine Colin , Svenning Jens‐Christian , Couvet Denis 
Published: November 2017

AbstractHumans are changing the biosphere by exerting pressure on land via different land uses with variable intensities. Quantifying the relative importance of the land‐use composition and intensity for communities may provide valuable insights for understanding community dynamics in human‐dominated landscapes. Here, we evaluate the relative importance of the land‐use composition versus land‐use intensity on the bird community structure in the highly human‐dominated region surrounding Paris, France. The land‐use composition was calculated from a land cover map, whereas the land‐use intensity (reverse intensity) was represented by the primary productivity remaining after human appropriation (NPPremaining), which was estimated using remote sensing imagery. We used variance partitioning to evaluate the relative importance of the land‐use composition versus intensity for explaining bird community species richness, total abundance, trophic levels, and habitat specialization in urban, farmland, and woodland habitats. The land‐use composition and intensity affected specialization and richness more than trophic levels and abundance. The importance of the land‐use intensity was slightly higher than that of the composition for richness, specialization, and trophic levels in farmland and urban areas, while the land‐use composition was a stronger predictor of abundance. The intensity contributed more to the community indices in anthropogenic habitats (farmland and urban areas) than to those in woodlands. Richness, trophic levels, and specialization in woodlands tended to increase with the NPPremaining value. The heterogeneity of land uses and intensity levels in the landscape consistently promoted species richness but reduced habitat specialization and trophic levels. This study demonstrates the complementarity of NPPremaining to the land‐use composition for understanding community structure in anthropogenic landscapes. Our results show, for the first time, that the productivity remaining after human appropriation is a determinant driver of animal community patterns, independent of the type of land use.
The role of habitat choice in micro‐evolutionary dynamics: An experimental study on the Mediterranean killifish Aphanius fasciatus (Cyprinodontidae)
Authors: Angeletti Dario , Sebbio Claudia , Carlini Alessandro , Strinati Claudia , Nascetti Giuseppe , Carere Claudio , Cimmaruta Roberta 
Published: November 2017

AbstractHabitat choice is defined as a nonrandom distribution of genotypes in different microhabitats. Therefore, it could exert a great impact on the genetic variance of natural populations by promoting genetic divergence, local adaptation, and may even lead to sympatric speciation. Despite this potential role in micro‐ and macro‐evolutionary processes, there is little empirical evidence that the various genotypes within a population may differ in habitat choice‐related behaviors. Here, we tested whether habitat choice may have contributed to genetic divergence within a local population of the Mediterranean killifish Aphanius fasciatus, which emerged between groups inhabiting microhabitats with different oxygen concentrations during previous field studies. In a first experiment, we studied the distribution of individuals in conditions of hypoxia and normoxia to test whether they had a different ability to shy away from a hypoxic environment; in a second experiment, we analyzed the individual behavior of fish separately in the two conditions, to verify whether they showed peculiar behavioral responses linked to a possible differential distribution. We then analyzed the six allozyme loci, whose allelic and genotypic frequencies were significantly divergent in the previous studies. In the first test, we found that the distribution of the two homozygote genotypes of the glucose‐6‐phosphate isomerase‐1 locus (GPI‐1) was significantly different between the hypoxic and the normoxic conditions. During the second test, all individuals were more active in hypoxic conditions, but the two GPI‐1 homozygotes showed a significant difference in time spent performing surface breathing, which was consistent with their distribution observed in the first experiment. These results provide evidence that individual behavioral traits, related to genetic features, may lead to a nonrandom distribution of genotypes in heterogeneous although contiguous microhabitats and, consequently, that habitat choice can play a significant role in driving the micro‐evolutionary dynamics of this species.
Rapid assessment of forest canopy and light regime using smartphone hemispherical photography
Authors: Bianchi Simone , Cahalan Christine , Hale Sophie , Gibbons James Michael 
Published: November 2017

AbstractHemispherical photography (HP), implemented with cameras equipped with “fisheye” lenses, is a widely used method for describing forest canopies and light regimes. A promising technological advance is the availability of low‐cost fisheye lenses for smartphone cameras. However, smartphone camera sensors cannot record a full hemisphere. We investigate whether smartphone HP is a cheaper and faster but still adequate operational alternative to traditional cameras for describing forest canopies and light regimes.We collected hemispherical pictures with both smartphone and traditional cameras in 223 forest sample points, across different overstory species and canopy densities. The smartphone image acquisition followed a faster and simpler protocol than that for the traditional camera. We automatically thresholded all images. We processed the traditional camera images for Canopy Openness (CO) and Site Factor estimation. For smartphone images, we took two pictures with different orientations per point and used two processing protocols: (i) we estimated and averaged total canopy gap from the two single pictures, and (ii) merging the two pictures together, we formed images closer to full hemispheres and estimated from them CO and Site Factors. We compared the same parameters obtained from different cameras and estimated generalized linear mixed models (GLMMs) between them.Total canopy gap estimated from the first processing protocol for smartphone pictures was on average significantly higher than CO estimated from traditional camera images, although with a consistent bias. Canopy Openness and Site Factors estimated from merged smartphone pictures of the second processing protocol were on average significantly higher than those from traditional cameras images, although with relatively little absolute differences and scatter.Smartphone HP is an acceptable alternative to HP using traditional cameras, providing similar results with a faster and cheaper methodology. Smartphone outputs can be directly used as they are for ecological studies, or converted with specific models for a better comparison to traditional cameras.
Life history traits and functional processes generate multiple pathways to ecological stability
Authors: DeLong John P. , Hanley Torrance C. , Gibert Jean P. , Puth Linda M. , Post David M. 
Published: November 2017

AbstractStability contributes to the persistence of ecological communities, yet the interactions among different stabilizing forces are poorly understood. We assembled mesocosms with an algal resource and one to eight different clones of the consumer Daphnia ambigua and tracked algal and Daphnia abundances through time. We then fitted coupled ordinary differential equations (ODEs) to the consumer–resource time series. We show that variation in different components of stability (local stability and the magnitude of population fluctuations) across mesocosms arises through variation in life history traits and the functional processes represented by ODE model parameters. Local stability was enhanced by increased algal growth rate and Daphnia mortality and foraging rate. Population fluctuations were dampened by high Daphnia conversion efficiency and lower interaction strengths, low algal growth rate, high Daphnia death rate, and low Daphnia foraging. These results indicate that (1) stability in consumer–resource systems may arise through the net effect of multiple related stabilizing pathways and (2) different aspects of stability can vary independently and may respond in opposite directions to the same forces.