bluuebunny/crossref_metadata_2025 huggingface dataset:
Using phosphine ligands with a biological role to modulate reactivity in novel platinum complexes
Authors: Echeverri Marcelo , Alvarez-Valdés Amparo , Navas Francisco , Perles Josefina , Sánchez-Pérez Isabel , Quiroga A. G.
Published: February 2018

Three platinum complexes with
cis
and
trans
configuration
cis
-[Pt(TCEP)
2
Cl
2
],
cis
-[Pt(tmTCEP)
2
Cl
2
] and
trans
-[Pt(TCEP)
2
Cl
2
], where TCEP is tris(2-carboxyethyl)phosphine, have been synthesized and fully characterized by usual techniques including single-crystal X-ray diffraction for
trans
-[Pt(TCEP)
2
Cl
2
] and
cis
-[Pt(tmTCEP)
2
Cl
2
]. Here, we also report on an esterification process of TCEP, which takes place in the presence of alcohols, leading to a platinum complex coordinated to an ester tmTCEP (2-methoxycarbonylethyl phosphine) ligand. The stability in solution of the three compounds and their interaction with biological models such as DNA (pBR322 and calf thymus DNA) and proteins (lysozyme and RNase) have also been studied.
The comparative evidence for urban species sorting by anthropogenic noise
Authors: Cardoso Gonçalo C. , Hu Yang , Francis Clinton D.
Published: February 2018

Anthropogenic noise is more intense at lower sound frequencies, which could decrease urban tolerance of animals with low-frequency vocalizations. Four large comparative studies tested whether anthropogenic noise filters bird species according to the sound frequencies they use and produced discrepant results. We reanalysed data from these studies to explain their different results. Urban tolerance of bird species (defined here as often occurring and breeding in cities) is very weakly related to urban preference or relative abundance (defined based on changes in population density from urban to nearby rural environments). Data on urban preference/abundance are potentially accurate for individual cities but differ among cities for the same species, whereas existing data on urban tolerance are coarser but provide a more global synthesis. Cross-species comparisons find a positive association between the sound frequency of song and urban tolerance, but not urban preference/abundance. We found that showing an association between song frequency and urban tolerance requires controlling for additional species traits that influence urban living. On the contrary, controlling for other species traits is not required to show a positive association between song frequency and use of noisy relative to quiet areas within the same type of environment. Together, comparative evidence indicates that masking by urban noise is part of a larger set of factors influencing urban living: all else being equal, species with high-frequency sounds are more likely to tolerate cities than species with low-frequency sounds, but they are not more likely to prefer, or to be more abundant in, urban than non-urban habitats.
Nematic director fields and topographies of solid shells of revolution
Authors: Warner Mark , Mostajeran Cyrus
Published: February 2018

We solve the forward and inverse problems associated with the transformation of flat sheets with circularly symmetric director fields to surfaces of revolution with non-trivial topography, including Gaussian curvature, without a stretch elastic cost. We deal with systems slender enough to have a small bend energy cost. Shape change is induced by light or heat causing contraction along a non-uniform director field in the plane of an initially flat nematic sheet. The forward problem is, given a director distribution, what shape is induced? Along the way, we determine the Gaussian curvature and the evolution with induced mechanical deformation of the director field and of material curves in the surface (proto-radii) that will become radii in the final surface. The inverse problem is, given a target shape, what director field does one need to specify? Analytic examples of director fields are fully calculated that will, for specific deformations, yield catenoids and paraboloids of revolution. The general prescription is given in terms of an integral equation and yields a method that is generally applicable to surfaces of revolution.
Analytic analysis of auxetic metamaterials through analogy with rigid link systems
Authors: Rayneau-Kirkhope Daniel , Zhang Chengzhao , Theran Louis , Dias Marcelo A.
Published: February 2018

In recent years, many structural motifs have been designed with the aim of creating auxetic metamaterials. One area of particular interest in this subject is the creation of auxetic material properties through elastic instability. Such metamaterials switch from conventional behaviour to an auxetic response for loads greater than some threshold value. This paper develops a novel methodology in the analysis of auxetic metamaterials which exhibit elastic instability through analogy with rigid link lattice systems. The results of our analytic approach are confirmed by finite-element simulations for both the onset of elastic instability and post-buckling behaviour including Poisson’s ratio. The method gives insight into the relationships between mechanisms within lattices and their mechanical behaviour; as such, it has the potential to allow existing knowledge of rigid link lattices with auxetic paths to be used in the design of future buckling-induced auxetic metamaterials.
Macroevolutionary patterning of woodpecker drums reveals how sexual selection elaborates signals under constraint
Authors: Miles Meredith C. , Schuppe Eric R. , Ligon R. Miller , Fuxjager Matthew J.
Published: February 2018

Sexual selection drives elaboration in animal displays used for competition and courtship, but this process is opposed by morphological constraints on signal design. How do interactions between selection and constraint shape display evolution? One possibility is that sexual selection continues exaggeration under constraint by operating differentially on each signal component in complex, modular displays. This is seldom studied on a phylogenetic scale, but we address the issue herein by studying macroevolutionary patterning of woodpecker drum displays. These territorial displays are produced when an individual rapidly hits its bill on a hard surface, and drums vary across species in the number of beats included (length) and the rate of drumbeat production (speed). We report that species body size limits drum speed, but not drum length. As a result of this biomechanical constraint, there is less standing variation in speed than length. We also uncover a positive relationship between sexual size dimorphism and the unconstrained trait (length), but with no effect on speed. This suggests that when morphology limits the exaggeration of one component, sexual selection instead exaggerates the unconstrained trait. Modular displays therefore provide the basis for selection to find novel routes to phenotypic elaboration after previous ones are closed.
apterous Aspecifies dorsal wing patterns and sexual traits in butterflies
Authors: Prakash Anupama , Monteiro Antónia
Published: February 2018

Butterflies have evolved different colour patterns on their dorsal and ventral wing surfaces to serve different signalling functions, yet the developmental mechanisms controlling surface-specific patterning are still unknown. Here, we mutate both copies of the transcription factorapterousinBicyclus anynanabutterflies using CRISPR/Cas9 and show thatapterous A,expressed dorsally, functions both as a repressor and modifier of ventral wing colour patterns, as well as a promoter of dorsal sexual ornaments in males. We propose that the surface-specific diversification of wing patterns in butterflies proceeded via the co-option ofapterous Aor its downstream effectors into various gene regulatory networks involved in the differentiation of discrete wing traits. Further, interactions betweenapterousand sex-specific factors such asdoublesexmay have contributed to the origin of sexually dimorphic surface-specific patterns. Finally, we discuss the evolution of eyespot number diversity in the family Nymphalidae within the context of developmental constraints due toapterousregulation.
Pattern and process in hominin brain size evolution are scale-dependent
Authors: Du Andrew , Zipkin Andrew M. , Hatala Kevin G. , Renner Elizabeth , Baker Jennifer L. , Bianchi Serena , Bernal Kallista H. , Wood Bernard A.
Published: February 2018

A large brain is a defining feature of modern humans, yet there is no consensus regarding the patterns, rates and processes involved in hominin brain size evolution. We use a reliable proxy for brain size in fossils, endocranial volume (ECV), to better understand how brain size evolved at both clade- and lineage-level scales. For the hominin clade overall, the dominant signal is consistent with a gradual increase in brain size. This gradual trend appears to have been generated primarily by processes operating within hypothesized lineages—64% or 88% depending on whether one uses a more or less speciose taxonomy, respectively. These processes were supplemented by the appearance in the fossil record of larger-brainedHomospecies and the subsequent disappearance of smaller-brainedAustralopithecusandParanthropustaxa. When the estimated rate of within-lineage ECV increase is compared to an exponential model that operationalizes generation-scale evolutionary processes, it suggests that the observed data were the result of episodes of directional selection interspersed with periods of stasis and/or drift; all of this occurs on too fine a timescale to be resolved by the current human fossil record, thus producing apparent gradual trends within lineages. Our findings provide a quantitative basis for developing and testing scale-explicit hypotheses about the factors that led brain size to increase during hominin evolution.
Microbe Profile: Corynebacterium diphtheriae – an old foe always ready to seize opportunity
Authors: Hoskisson Paul A.
Published: February 2018

Corynebacterium diphtheriae is a globally important Gram-positive aerobic Actinobacterium capable of causing the toxin-mediated disease, diphtheria. Diphtheria was a major cause of childhood mortality prior to the introduction of the toxoid vaccine, yet it is capable of rapid resurgence following the breakdown of healthcare provision, vaccination or displacement of people. The mechanism and treatment of toxin-mediated disease is well understood, however there are key gaps in our knowledge on the basic biology of C. diphtheriae particularly relating to host colonisation, the nature of asymptomatic carriage, population genomics and host adaptation.
Genetic meta-analysis identifies 9 novel loci and functional pathways for Alzheimer’s disease risk
Authors: Jansen Iris E , Savage Jeanne E , Watanabe Kyoko , Bryois Julien , Williams Dylan M , Steinberg Stacy , Sealock Julia , Karlsson Ida K , Hägg Sara , Athanasiu Lavinia , Voyle Nicola , Proitsi Petroula , Witoelar Aree , Stringer Sven , Aarsland Dag , Almdahl Ina S , Andersen Fred , Bergh Sverre , Bettella Francesco , Bjornsson Sigurbjorn , Brækhus Anne , Bråthen Geir , de Leeuw Christiaan , Desikan Rahul S , Djurovic Srdjan , Dumitrescu Logan , Fladby Tormod , Homan Timothy , Jonsson Palmi V , Kiddle Steven J , Rongve K Arvid , Saltvedt Ingvild , Sando Sigrid B. , Selbæk Geir , Skenne Nathan , Snaedal Jon , Stordal Eystein , Ulstein Ingun D. , Wang Yunpeng , White Linda R , Hjerling-Leffler Jens , Sullivan Patrick F , van der Flier Wiesje M , Dobson Richard , Davis Lea K. , Stefansson Hreinn , Stefansson Kari , Pedersen Nancy L , Ripke Stephan , Andreassen Ole A , Posthuma Danielle
Published: February 2018

Late onset Alzheimer’s disease (AD) is the most common form of dementia with more than 35 million people affected worldwide, and no curative treatment available. AD is highly heritable and recent genome-wide meta-analyses have identified over 20 genomic loci associated with AD, yet only explaining a small proportion of the genetic variance indicating that undiscovered loci exist. Here, we performed the largest genome-wide association study of clinically diagnosed AD and AD-by-proxy (71,880 AD cases, 383,378 controls). AD-by-proxy status is based on parental AD diagnosis, and showed strong genetic correlation with AD (rg=0.81). Genetic meta analysis identified 29 risk loci, of which 9 are novel, and implicating 215 potential causative genes. Independent replication further supports these novel loci in AD. Associated genes are strongly expressed in immune-related tissues and cell types (spleen, liver and microglia). Furthermore, gene-set analyses indicate the genetic contribution of biological mechanisms involved in lipid-related processes and degradation of amyloid precursor proteins. We show strong genetic correlations with multiple health-related outcomes, and Mendelian randomisation results suggest a protective effect of cognitive ability on AD risk. These results are a step forward in identifying more of the genetic factors that contribute to AD risk and add novel insights into the neurobiology of AD to guide new drug development.
Common variants inABCG8andTRAF3genes confer risk for gallstone disease and gallbladder cancer in admixed Latinos with Mapuche Native American ancestry
Authors: Bustos Bernabé I. , Pérez-Palma Eduardo , Buch Stephan , Azócar Lorena , Riveras Eleodoro , Ugarte Giorgia D. , Toliat Mohammad , Nürnberg Peter , Lieb Wolfgang , Franke Andre , Hinz Sebastian , Burmeister Greta , von Schönfels Witigo , Schafmayer Clemens , Völzke Henry , Völker Uwe , Homuth Georg , Lerch Marcus M. , Santos José Luis , Puschel Klaus , Bambs Claudia , Gutiérrez Rodrigo A. , Hampe Jochen , De Ferrari Giancarlo V. , Miquel Juan Francisco
Published: February 2018

Background

Latin Americans and Chilean Amerindians have the highest prevalence of cholesterol gallstone disease (GSD) and gallbladder cancer (GBC) in the world. A handful of loci have been associated with GSD in populations of predominantly European ancestry, however they only explain a small portion of the population-attributable risk of the disease.

Methods

We performed a genome-wide association study (GWAS) for GSD in 1,095 admixed Latinos with Mapuche Native American Ancestry, followed by a replication analysis of 10 candidate single nucleotide polymorphisms (SNPs) with suggestive genome-wide significance (P<1×10−5) in 1,643 individuals. Disease status was assessed by cholecystectomy or abdominal ultrasonography. Logistic regression analyses were adjusted for age, sex, BMI, Type 2 Diabetes and Amerindian ancestry. Associated variants were further examined in two large GSD European populations and in a Chilean gallbladder cancer (GBC) cohort. We determined the expression levels of a novel GSD-candidate gene in normal and GSD-tissue samples.

Results

We consistently replicated theABCG8gene (rs11887534; P=3.24×10−8, OR=1.74) associated with GSD in admixed Latinos and identified a novel candidate signal within theTRAF3gene on chromosome 14 (rs12882491; P=1.11×10−7, OR=1.40).ABCG8andTRAF3variants also conferred risk to GBC. Gene expression analyses indicated thatTRAF3levels were significantly decreased in the gallbladder (P=0.015) and the duodenal mucosa (P=0.001) of affected GSD individuals compared to healthy controls.

Conclusions

We confirmedABCG8and identifiedTRAF3both associated with GSD and GBC in admixed Latinos. Decreased TRAF3 expression levels could enhance gallbladder inflammation as is observed in GSD and GSD-associated GBC.
Tbx1regulates extracellular matrix-cell interactions in the second heart field
Authors: Alfano Daniela , Altomonte Alessandra , Cortes Claudio , Bilio Marchesa , Kelly Robert G. , Baldini Antonio
Published: February 2018

Tbx1,the major candidate gene for DiGeorge or 22q11.2 deletion syndrome, is required for efficient incorporation of cardiac progenitors (CPs) of the second heart field (SHF) into the heart. However, the mechanisms by which TBX1 regulates this process are still unclear. Here, we have used two independent models, mouse embryos and cultured cells, to define the role of TBX1 in establishing morphological and dynamic characteristics of SHF in the mouse. We found that loss of TBX1 impairs extra cellular matrix (ECM)-integrin-focal adhesion (FA) signaling in both models. Mosaic analysis in embryos showed that this function is non-cell autonomous and, in cultured cells, loss of TBX1 impairs cell migration and focal adhesions. Additionally, we found that ECM-mediated outside-in integrin signaling is disrupted upon loss of TBX1. Finally, we show that interfering with the ECM-integrin-FA axis between E8.5 and E9.5 in mouse embryos, corresponding to the time window within which TBX1 is required in the SHF, causes outflow tract dysmorphogenesis. Our results demonstrate that TBX1 is required to maintain the integrity of ECM-cell interactions in the SHF, and that this interaction is critical for cardiac outflow tract development. More broadly, our data identifies a novel TBX1 downstream pathway as an important player in SHF tissue architecture and cardiac morphogenesis.
Whole-genome sequencing of parvoviruses from wild and domestic animals in Brazil provides new insights into parvovirus distribution and diversity
Authors: Souza William Marciel de , Dennis Tristan Philip Wesley , Fumagalli Marcílio Jorge , de Araujo Jansen , Sabino-Santos Gilberto , Maia Felipe Gonçalves Motta , Acrani Gustavo Olszanski , Carrasco Adriano de Oliveira Torres , Romeiro Marilia Farignoli , Modha Sejal , Vieira Luiz Carlos , Ometto Tatiana Lopes , Queiroz Luzia Helena , Durigon Edison Luiz , Nunes Márcio Roberto Teixeira , Figueiredo Luiz Tadeu Moraes , Gifford Robert James
Published: February 2018

Parvoviruses (family Parvoviridae) are small, single-stranded DNA viruses. Many parvoviral pathogens of medical, veterinary and ecological importance have been identified. In this study, we used high-throughput sequencing (HTS) to investigate the diversity of parvoviruses infecting wild and domestic animals in Brazil. We identified 21 parvovirus sequences (including twelve nearly complete genomes and nine partial genomes) in samples derived from rodents, bats, opossums, birds and cattle in Pernambuco, São Paulo, Paraná and Rio Grande do Sul states. These sequences were investigated using phylogenetic and distance-based approaches, and were thereby classified into eight parvovirus species (six of which have not been described previously), representing six distinct genera in the subfamily Parvovirinae. Our findings extend the known biogeographic range of previously characterized parvovirus species, and the known host range of three parvovirus genera (Dependovirus, Aveparvovirus, and Tetraparvovirus). Moreover, our investigation provides a window into the ecological dynamics of parvovirus infections in vertebrates, revealing that many parvovirus genera contain well-defined sub-lineages that circulate widely throughout the world within particular taxonomic groups of hosts.
Information sharing for a coordination game in fluctuating environments
Authors: Paarporn Keith , Eksin Ceyhun , Weitz Joshua S.
Published: February 2018

Collective action dilemmas pervade the social and biological sciences - from human decision-making to bacterial quorum sensing. In these scenarios, individuals sense cues from the environment to adopt a suitable phenotype or change in behavior. However, when cues include signals from other individuals, then the appropriate behavior of each individual is linked. Here, we develop a framework to quantify the influence of information sharing on individual behavior in the context of two player coordination games. In this framework, the environment stochastically switches between two states, and the state determines which one of two actions players must coordinate on. Given a stochastically switching environment, we then consider two versions of the game that differ in the way players acquire information. In the first model, players independently sense private environmental cues, but do not communicate with each other. We find there are two types of strategies that emerge as Nash equilibria and fitness maximizers - players prefer to commit to one particular action when private information is poor, or prefer to employ phenotypic plasticity when it is good. The second model adds an additional layer of communication, where players share social cues as well. When the quality of social information is high, we find the socially optimal strategy is a novel “majority logic” strategy that bases decision-making on social cues. Our game-theoretic approach offers a principled way of investigating the role of communication in group decision-making under uncertain conditions.
Comparative assessment of strategies to identify similar ligand-binding pockets in proteins
Authors: Govindaraj Rajiv Gandhi , Brylinski Michal
Published: February 2018

Background

Detecting similar ligand-binding sites in globally unrelated proteins has a wide range of applications in modern drug discovery, including drug repurposing, the prediction of side effects, and drug-target interactions. Although a number of techniques to compare binding pockets have been developed, this problem still poses significant challenges.

Results

We evaluate the performance of three algorithms to calculate similarities between ligand-binding sites, APoc, SiteEngine, and G-LoSA. Our assessment considers not only the capabilities to identify similar pockets and to construct accurate local alignments, but also the dependence of these alignments on the sequence order. We point out certain drawbacks of previously compiled datasets, such as the inclusion of structurally similar proteins, leading to an overestimated performance. To address these issues, a rigorous procedure to prepare unbiased, high-quality benchmarking sets is proposed. Further, we conduct a comparative assessment of techniques directly aligning binding pockets to indirect strategies employing structure-based virtual screening with AutoDock Vina and rDock.

Conclusions

Thorough benchmarks reveal that G-LoSA offers a fairly robust overall performance, whereas the accuracy of APoc and SiteEngine is satisfactory only against easy datasets. Moreover, combining various algorithms into a meta-predictor improves the performance of existing methods to detect similar binding sites in unrelated proteins by 5-10%. All data reported in this paper are freely available at https://osf.io/6ngbs/.
Echo State Networks Ensemble for SSVEP Dynamical Online Detection
Authors: Ibanez-Soria D , Soria-Frisch A. , Garcia-Ojalvo J , Ruffini G
Published: February 2018

Background

Recent years have witnessed an increased interest in the use of steady state visual evoked potentials (SSVEPs) in brain computer interfaces (BCI), SSVEP is considered a stationary brain process that appears when gazing at a stimulation light source.

New Methods

The complex nature of brain processes advocates for non-linear EEG analysis techniques. In this work we explore the use of an Echo State Networks (ESN) based architecture for dynamical SSVEP detection.

Results

When simulating a 6-degrees of freedom BCI system, an information transfer rate of 49bits/min was achieved. Detection accuracy proved to be similar for observation windows ranging from 0.5 to 4 seconds.

Comparison with existing methods

SSVEP detection performance has been compared to standard canonical correlation analysis (CCA). CCA achieved a maximum information transfer rate of 21 bits/minute. In this case detection accuracy increased along with the observation window length

Conclusions

According to here presented results ESN outperforms standard canonical correlation and has proved to require shorter observation time windows. However ESN and CCA approaches delivered diverse classification accuracies at subject level for various stimulation frequencies, proving to be complementary methods. A possible explanation of these results may be the occurrence of evoked responses of different nature, which are then detected by different approaches. While reservoir computing methods are able to detect complex dynamical patterns and/or complex synchronization among EEG channels, CCA exclusively captures stationary patterns. Therefore, the ESN-based approach may be used to extend the definition of steady-state response, considered so far a stationary process.

Highlights

We present a novel SSVEP dynamical detection approach based on ESN.

This is the first time ESNs are applied to SSVEP based BCI systems.

We provide experimental validation of proposed methodology.

Experimental results indicate non-stationarity in SSVEP patterns.
Transposable elements generate regulatory novelty in a tissue-specific fashion
Authors: Trizzino Marco , Kapusta Aurélie , Brown Christopher D.
Published: February 2018

Background

Transposable elements (TE) are an important source of evolutionary novelty in gene regulation. However, the mechanisms by which TEs contribute to gene expression are largely uncharacterized.

Results

Here, we leverage Roadmap and GTEx data to investigate the association of TEs with active and repressed chromatin in 24 tissues. We find 112 human TE types enriched in active regions of the genome across tissues. SINEs and DNA transposons are the most frequently enriched classes, while LTRs are often enriched in a tissue-specific manner. We report across-tissue variability in TE enrichment in active regions. Genes with consistent expression across tissues are less likely to be associated with TE insertions. TE presence in repressed regions similarly follows tissue-specific patterns. Moreover, different TE classes correlate with different repressive marks: Long Terminal Repeat Retrotransposons (LTRs) and Long Interspersed Nuclear Elements (LINEs) are overrepresented in regions marked by H3K9me3, while the other TEs are more likely to overlap regions with H3K27me3. Young TEs are typically enriched in repressed regions and depleted in active regions. We detect multiple instances of TEs that are enriched in tissue-specific active regulatory regions. Such TEs contain binding sites for transcription factors that are master regulators for the given tissue. These TEs are enriched in intronic enhancers, and their tissue-specific enrichment correlates with tissue-specific variations in the expression of the nearest genes.

Conclusions

We provide an integrated overview of the contribution of TEs to human gene regulation. Expanding previous analyses, we demonstrate that TEs can potentially contribute to the turnover of regulatory sequences in a tissue-specific fashion.
A LiK-edge XANES study of salts and minerals
Authors: O'Shaughnessy Cedrick , Henderson Grant S. , Moulton Benjamin J. A. , Zuin Lucia , Neuville Daniel R.
Published: February 2018

The first comprehensive LiK-edge XANES study of a varied suite of Li-bearing minerals is presented. Drastic changes in the bonding environment for lithium are demonstrated and this can be monitored using the position and intensity of the main LiK-absorption edge. The complex silicates confirm the assignment of the absorption edge to be a convolution of triply degeneratep-like states as previously proposed for simple lithium compounds. The LiK-edge position depends on the electronegativity of the element to which it is bound. The intensity of the first peak varies depending on the existence of a 2pelectron and can be used to evaluate the degree of ionicity of the bond. The presence of a 2pelectron results in a weak first-peak intensity. The maximum intensity of the absorption edge shifts to lower energy with increasing SiO2content for the lithium aluminosilicate minerals. The bond length distortion of the lithium aluminosilicates decreases with increasing SiO2content, thus increased distortion leads to an increase in edge energy which measures lithium's electron affinity.
Evaluation of the UFXC32k photon-counting detector for pump–probe experiments using synchrotron radiation
Authors: Koziol Anna , Bordessoule Michel , Ciavardini Alessandra , Dawiec Arkadiusz , Da Silva Paulo , Desjardins Kewin , Grybos Pawel , Kanoute Brahim , Laulhe Claire , Maj Piotr , Menneglier Claude , Mercere Pascal , Orsini Fabienne , Szczygiel Robert
Published: February 2018

This paper presents the performance of a single-photon-counting hybrid pixel X-ray detector with synchrotron radiation. The camera was evaluated with respect to time-resolved experiments, namely pump–probe–probe experiments held at SOLEIL. The UFXC camera shows very good energy resolution of around 1.5 keV and allows the minimum threshold setting to be as low as 3 keV keeping the high-count-rate capabilities. Measurements of a synchrotron characteristic filling mode prove the proper separation of an isolated bunch of photons and the usability of the detector in time-resolved experiments.
Zirconium tetrachloride revisited
Authors: Borjas Nevarez Rosendo , Balasekaran Samundeeswari Mariappan , Kim Eunja , Weck Philippe , Poineau Frederic
Published: February 2018

Zirconium tetrachloride, ZrCl4, is a strategic material with wide-ranging applications. Until now, only one crystallographic study on ZrCl4has been reported [Krebs (1970).Z. Anorg. Allg. Chem.378, 263–272] and that was more than 40 years ago. The compound used for the previous determination was prepared from ZrO2and Cl2–CCl4, and single-crystal X-ray diffraction (SCXRD) studies on ZrCl4obtained from Zr metal have not yet been reported. In this context, we prepared ZrCl4from the reaction of Zr metal and Cl2gas in a sealed tube and investigated its structure at 100, 150, 200, 250, and 300 K. At 300 K, the SCXRD analysis indicates that ZrCl4crystallizes in the orthorhombic space groupPca21[a= 6.262 (9),b= 7.402 (11),c= 12.039 (17) Å, andV= 558.0 (14) Å3] and consists of infinite zigzag chains of edge-sharing ZrCl6octahedra. This chain motif is similar to that observed previously in ZrCl4, but the structural parameters and space group differ. In the temperature range 100–300 K, no phase transformation was identified, while elongation of intra-chain Zr...Zr [3.950 (1) Å at 100 K and 3.968 (5) Å at 300 K] and inter-chain Cl...Cl [3.630 (3) Å at 100 K and 3.687 (9) Å at 300 K] distances occurred.
Supramolecular architectures in cytosinium 6-chloronicotinate monohydrate and 5-bromo-6-methylisocytosinium hydrogen sulfate
Authors: Swinton Darious Robert , Jasmine Nithianantham Jeeva , Karthikeyan Ammasai , Thomas Muthiah Packianathan , Perdih Franc
Published: February 2018

Aminopyrimidine derivatives are biologically important as they are components of nucleic acids and drugs. The crystals of two new salts, namely cytosinium 6-chloronicotinate monohydrate, C4H6N3O+·C6H3ClNO2−·H2O, (I), and 5-bromo-6-methylisocytosinium hydrogen sulfate (or 2-amino-5-bromo-4-oxo-6-methylpyrimidinium hydrogen sulfate), C5H7BrN3O+·HSO4−, (II), have been prepared and characterized by single-crystal X-ray diffraction. The pyrimidine ring of both compounds is protonated at the imine N atom. In hydrated salt (I), the primaryR22(8) ring motif (supramolecular heterosynthon) is formedviaa pair of N—H...O(carboxylate) hydrogen bonds. The cations, anions and water molecule are hydrogen bonded through N—H...O, N—H...N, O—H...O and C—H...O hydrogen bonds, formingR22(8),R32(7) andR55(21) motifs, leading to a hydrogen-bonded supramolecular sheet structure. The supramolecular double sheet structure is formedviawater–carboxylate O—H...O hydrogen bonds and π–π interactions between the anions and the cations. In salt (II), the hydrogen sulfate ions are linkedviaO—H...O hydrogen bonds to generate zigzag chains. The aminopyrimidinium cations are embedded between these zigzag chains. Each hydrogen sulfate ion bridges two cationsviapairs of N—H...O hydrogen bonds andvice versa, generating twoR22(8) ring motifs (supramolecular heterosynthon). The cations also interact with one anotherviahalogen–halogen (Br...Br) and halogen–oxygen (Br...O) interactions.
Characteristics of borrowers likely to benefit from loan modifications
Authors: Dodson Charles B. , Ahrendsen Bruce L.
Published: February 2018

Purpose

The purpose of this paper is to identify the characteristics of borrowers likely to benefit from loan modifications (restructuring) which includes concessions provided to the borrower from the lender.

Design/methodology/approach

Data were drawn from the US Department of Agriculture Farm Service Agency (FSA) for borrowers who had received an operating loan modification during 2005-2010. A logistic regression model is estimated to identify the characteristics associated with the likelihood of a borrower paying the modified loan as agreed or receiving a subsequent loan modification within seven years. Explanatory variables included financial condition, type and year of loan modification, farm type, organizational type, borrower demographics, and region.

Findings

Loans requiring more complex loan modifications and borrowers with previous loan restructuring, larger farms, little equity in loan collateral, little or no capital, and/or little to no liquidity are less likely to perform following loan restructuring, which could suggest a possible futility in providing concessions to these types of borrowers. Many of these borrowers ended up having a subsequent restructure within a short period of time. Most of the regional variability in loan performance appears to have been a result of land values and commodity prices and not jurisdictional laws.

Originality/value

FSA has followed a policy of providing loan modifications to the borrowers experiencing repayment problems for more than 25 years. Though farm financial conditions have remained relatively strong through 2016, a continuation of the low farm incomes and declining farm real estate values could increase farm loan repayment problems in upcoming years and increase interest in farm loan modifications from both lenders and policymakers. FSA’s experience provides a rich data source to examine and provide a better understanding of the costs and benefits associated with loan modifications.
Strengths, innovation, and opportunities in a burgeoning industry: an exploratory study
Authors: Duarte Alonso Abel , Sakellarios Nikolaos , Alexander Nevil , O’Brien Seamus
Published: February 2018

Purpose

The purpose of this paper is to examine key areas related to the craft brewing industry from the perspective of operators of micro and small craft breweries, and propose a framework based on the resourced-based theory of the firm and the theory of innovation. The areas investigated include participants’ perceived strengths of their craft brewery, involvement in innovative practices, opportunities for the craft brewing firm, and potential differences related to these areas based on the demographic characteristics of participants and their breweries.

Design/methodology/approach

Given its growing significance and economic contribution, the US craft brewery industry was chosen for this study. An online questionnaire was designed to gather data from craft brewery operators across the nation.

Findings

Product and service quality, knowledge, reputation, and expertise were revealed as key strengths, while creating new recipes and using social media tools were the most considered ways of innovating. Furthermore, opportunities were perceived through craft beer tourism, increased consumption, and quality improvements. Statistically significant differences emerged, particularly based on production levels, staff numbers, and involvement/no involvement in exports. Various associations between the findings and the adopted theoretical frameworks were revealed.

Originality/value

In terms of originality, the proposed refinement based on the adopted theoretical frameworks and findings facilitates understanding of the significance of resources and innovation, particularly for firms operating in a growing industry. Regarding value, the findings have important implications for the industry, for instance, in the marketing of craft brewing, as well as in the development of new craft brewing products.
Do statistics need foresight?
Authors: Kastrinos Nikos
Published: February 2018

Purpose

The purpose of this paper is to explore the relationship between foresight and official statistics in the context of sustainability and big-data. The aim is to draw ideas, guidance and lessons on how foresight could help national and international statistical offices deal with an increasingly turbulent and demanding environment.

Design/methodology/approach

The paper analyzes the challenges and opportunities posed by big data and sustainability for official statistics.

Findings

Drawing on the analysis of the BOHEMIA study – a foresight study launched by the European Commission to support its future policy for research and innovation – the paper proposes elements that could form a foresight programme for statistical offices.

Originality/value

Statistical offices and foresight have been worlds apart. The need to engage with each other is a recent and interesting phenomenon.
Role of “perceived risks” in adopting mobile government (m-government) services in India
Authors: Saxena Stuti
Published: February 2018

Purpose

This paper aims to investigate the role of “perceived risks” in adopting mobile government (m-government) services in India.

Design/methodology/approach

Conceding that “privacy risks” are one of the major factors that influence the adoption of e-services, the impact of “perceived risks” alongside “social efficacy,” “influence” of significant others and “attitude” on the adoption of m-government services in India has been underlined here. Specifically, the study has been conducted with 311 actual m-government users and constructs have been derived from existing theories like Technology Acceptance Model (TAM), Unified Theory of Acceptance and Use of Technology (UTAUT) and Theory of Planned Behavior (TPB). Multiple regression analysis has been conducted to analyze the data focused on constructs as: Perceived Risks (PR), Influence (I), Self-efficacy (SE), Attitude (ATT) and Behavioral Intention to Adopt m-government services (BI).

Findings

Results show that while the respondents perceive that adoption of m-government services is risk-free and safe, there is no impact of the interpersonal relationships on m-government adoption. There is more inclination to adopt m-government services conceding that the respondents perceive that they have the self-efficacy to operate such services. M-government services are being tapped regularly by the respondents and there is more inclination to adopt m-government services among the public sector employees and self-employed respondents in comparison with the ones who are students or unemployed. In terms of age, those in the age group of 31–50 are more inclined to adopt m-government services in comparison with the rest.

Originality/value

Exploration of “perceived risks” and other factors has been less in the context of m-government studies. The present study fills the gap in two ways: first, it undertakes the investigation in a developing country conceding that empirical studies on m-government adoption are few in Indian context, and second, it throws light on the role of “adoption” of m-government services in contrast with the “use” of e-government services.
Mobile services adoption in a hospitality consumer context
Authors: Rita Paulo , Oliveira Tiago , Estorninho António , Moro Sérgio
Published: February 2018

Purpose

This study aims to present a model drawn on both the extension of the unified theory of acceptance and use of technology (UTAUT2) and the perceived value for explaining consumer behavior toward mobile hospitality services (MHS) from two perspectives: intention to use and recommendation.

Design/methodology/approach

The partial least square (PLS) was applied to data gathered from 348 validated responses to a survey to test a number of research hypotheses.

Findings

Results found that the proposed conceptual model explains 62 per cent of the intention to use of MHS and 51 per cent of the variation in the recommendation. Perceived value plays a role in explaining both the intention to use and recommend MHS, with both constructs also helping in explaining behavior intention, to which effort expectancy, facilitating conditions and performance expectancy also contribute.

Originality/value

This research goes beyond perceived value by combining it with a cornerstone model, UTAUT2, used in technology adoption studies. The paper addresses updated MHS that include but are not limited to mobile hotel reservations.
A netnography of war heritage sites’ online narratives: user-generated content and destination marketing organizations communication at comparison
Authors: Irimiás Anna , Volo Serena
Published: February 2018

Purpose

The aim of this paper is twofold: to provide empirical evidence of the knowledge-sharing process within virtual communities interested in war heritage sites and to compare user-generated content (UGC) in virtual communities with destinations’ official communication about war heritage sites to identify, original and consumer-oriented narratives.

Design/methodology/approach

This study uses field research to investigate selected war heritage sites and to assess the destinations’ on-site communication; in-depth interviews to learn about the destination marketing organizations’ approaches to communication; and netnography with content analysis of text and pictures to evaluate the online knowledge shared within virtual communities on the investigated war heritage sites. A comparison between users-generated content and official destination management organizations’ (DMOs) communication was carried out.

Findings

The results show that the destinations under investigation have invested significantly to develop war heritage tourism, but they still struggle to attract tourists. The comparison between DMOs communication narratives and users-generated content shows that DMOs fail to use emotional involvement and accurate historic knowledge which seems to be at the basis of UGC narratives. Indeed, history passionates posts, pictures, comments and exchanges are emotionally engaging and DMOs could benefit from the user-generated content approach to improve institutional communication on war heritage sites.

Research limitations/implications

Further studies could survey history passionates, both online and offline, as to better explore the relationship between contributing to virtual communities’ content and visitation patterns of war heritage sites. Incorporating more emotionally engaging narratives, DMOs could enhance their communication and create virtual spaces where knowledgeable tourists can share information and experiences.

Originality/value

This paper contributes to the understanding of online knowledge sharing in the context of war heritage tourism. The comparison between UGC in virtual communities and official destinations’ narratives shows the potential of spontaneous knowledge sharing versus structured online communication and how the latter could benefit UGC.
Structure-integration relationships in oil and gas supply chains
Authors: Ebrahimi Seyed Mohammad , Koh S.C.L. , Genovese Andrea , Kumar Niraj
Published: February 2018

Purpose

Although studies have demonstrated the importance of supply chain integration (SCI) strategies in improving firm performance, very little is understood about how the organizational structure (OS) of focal firms affects the successful implementation of SCI initiatives across supply chains (SCs). Taking into consideration the importance of the oil and gas (O&G) industry, as well as the impact of uncertainties on OS and strategy choices, it is important to understand how OS and SCI affect the operational performance of O&G SCs. The paper aims to discuss this issue.

Design/methodology/approach

Taking a contingency approach and using a global sample of 181 O&G firms, this study examines the mediating role of internal, customer, and supplier integration on the relationship between three main dimensions of OS – the degree of centralization, formalization, and hierarchical relationships and operational performance, using structural equation modeling.

Findings

Findings reveal that OS dimensions negatively impact operational performance. Further testing for the mediation found that by increasing SCI, O&G SCs can mitigate the negative effect of high centralization, formalization, and hierarchical relationship on operational performance.

Research limitations/implications

Classifying OS into “structuring” and “structural,” this research provides evidence on which of the two has a stronger negative impact on operational performance. This is significant since it may be difficult for O&G companies to restructure and reform their OS.

Originality/value

This study examines the impact of OS and SCI on improving the operational performance of the O&G SCs. Theoretical and practical contributions to the field of operations management and organizational studies are also discussed.
Revisiting service quality through the lens of experience-centric services
Authors: Beltagui Ahmad , Candi Marina
Published: February 2018

Purpose

The purpose of this paper is to revisit prevailing notions of service quality by developing and testing a model of service quality for experience-centric services.

Design/methodology/approach

By problematizing the service quality literature, a model is developed to capture impacts of outcome-achievement, instrumental performance and expressive performance on customer loyalty. A multi-group structural equation model is tested to establish the moderating effect of perceived service character – utilitarian or hedonic.

Findings

Outcome-achievement mediates the direct relationships between instrumental and expressive performance, respectively, and loyalty; the strength of these relationships is moderated by perceived service character.

Research limitations/implications

Emotional design to improve the experience is effective provided the expected outcome is achieved. However, for services that customers perceive as experience-centric, the outcome may be somewhat ambiguously defined and expressive performance is valued more highly than instrumental performance.

Practical implications

Understanding customers’ perception of a service – whether customers seek value related to outcomes or emotions – is crucial when selecting appropriate measures of service quality and performance. Creating a good experience is generally beneficial, but it must be designed according to the character of the service in question.

Originality/value

The research presents empirical evidence on how service experience contributes to customer loyalty by testing a model of service quality that is suited to experience-centric services. Furthermore, it identifies the importance of understanding service character when designing and managing services.