bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid toroidal drop in compressional flow with arbitrary drop-to-ambient fluid viscosity ratio
Authors: Zabarankin Michael
Published: March 2016

Existing experiments show that a sufficiently fat toroidal drop freely suspended in another liquid shrinks towards its centre to form a spherical drop. However, recent simulations reveal that if a liquid torus with circular cross section is embedded in a compressional same-viscosity flow that acts to expand the torus, then depending on the torus radiusRand a capillary number Ca characterizing the balance between the viscous forces and the interfacial tension, the torus may either coalesce, expand indefinitely or attain a stationary shape. For each Ca less than 0.2, there is a single value ofR, called the critical radius, for which the torus attains the stationary shape. Here, the drop-to-ambient fluid viscosity ratio, λ, is assumed to be arbitrary. The corresponding two-phase Stokes flow problem is solved for a liquid toroidal drop with circular cross section in terms of stream functions in the toroidal coordinates. When λ=1, the stream functions admit a closed-form integral representation for a drop of arbitrary axisymmetric shape. ‘Stationary’ circular tori minimize a certain measure of the normal velocity over the interface, and as in the case of λ=1, their radii are expected to predict the critical ones for arbitrary λ and Ca in a certain range (e.g. for Ca<0.2 when λ=1). Streamlines about ‘stationary’ circular tori are analysed for various Ca and λ.
Too good to be true: when overwhelming evidence fails to convince
Authors: Gunn Lachlan J. , Chapeau-Blondeau François , McDonnell Mark D. , Davis Bruce R. , Allison Andrew , Abbott Derek
Published: March 2016

Is it possible for a large sequence of measurements or observations, which support a hypothesis, to counterintuitively decrease our confidence? Can unanimous support be too good to be true? The assumption of independence is often made in good faith; however, rarely is consideration given to whether a systemic failure has occurred. Taking this into account can cause certainty in a hypothesis to decrease as the evidence for it becomes apparently stronger. We perform a probabilistic Bayesian analysis of this effect with examples based on (i) archaeological evidence, (ii) weighing of legal evidence and (iii) cryptographic primality testing. In this paper, we investigate the effects of small error rates in a set of measurements or observations. We find that even with very low systemic failure rates, high confidence is surprisingly difficult to achieve; in particular, we find that certain analyses of cryptographically important numerical tests are highly optimistic, underestimating their false-negative rate by as much as a factor of 280.
Indium phosphide nanowires and their applications in optoelectronic devices
Authors: Zafar Fateen , Iqbal Azhar
Published: March 2016

Group IIIA phosphide nanocrystalline semiconductors are of great interest among the important inorganic materials because of their large direct band gaps and fundamental physical properties. Their physical properties are exploited for various potential applications in high-speed digital circuits, microwave and optoelectronic devices. Compared to II–VI and I–VII semiconductors, the IIIA phosphides have a high degree of covalent bonding, a less ionic character and larger exciton diameters. In the present review, the work done on synthesis of III–V indium phosphide (InP) nanowires (NWs) using vapour- and solution-phase approaches has been discussed. Doping and core–shell structure formation of InP NWs and their sensitization using higher band gap semiconductor quantum dots is also reported. In the later section of this review, InP NW-polymer hybrid material is highlighted in view of its application as photodiodes. Lastly, a summary and several different perspectives on the use of InP NWs are discussed.
On well-posedness of variational models of charged drops
Authors: Muratov Cyrill B. , Novaga Matteo
Published: March 2016

Electrified liquids are well known to be prone to a variety of interfacial instabilities that result in the onset of apparent interfacial singularities and liquid fragmentation. In the case of electrically conducting liquids, one of the basic models describing the equilibrium interfacial configurations and the onset of instability assumes the liquid to be equipotential and interprets those configurations as local minimizers of the energy consisting of the sum of the surface energy and the electrostatic energy. Here we show that, surprisingly, this classical geometric variational model is mathematically ill-posed irrespective of the degree to which the liquid is electrified. Specifically, we demonstrate that an isolated spherical droplet is never a local minimizer, no matter how small is the total charge on the droplet, as the energy can always be lowered by a smooth, arbitrarily small distortion of the droplet's surface. This is in sharp contrast to the experimental observations that a critical amount of charge is needed in order to destabilize a spherical droplet. We discuss several possible regularization mechanisms for the considered free boundary problem and argue that well-posedness can be restored by the inclusion of the entropic effects resulting in finite screening of free charges.
Millennial-scale faunal record reveals differential resilience of European large mammals to human impacts across the Holocene
Authors: Crees Jennifer J. , Carbone Chris , Sommer Robert S. , Benecke Norbert , Turvey Samuel T.
Published: March 2016

The use of short-term indicators for understanding patterns and processes of biodiversity loss can mask longer-term faunal responses to human pressures. We use an extensive database of approximately 18 700 mammalian zooarchaeological records for the last 11 700 years across Europe to reconstruct spatio-temporal dynamics of Holocene range change for 15 large-bodied mammal species. European mammals experienced protracted, non-congruent range losses, with significant declines starting in some species approximately 3000 years ago and continuing to the present, and with the timing, duration and magnitude of declines varying individually between species. Some European mammals became globally extinct during the Holocene, whereas others experienced limited or no significant range change. These findings demonstrate the relatively early onset of prehistoric human impacts on postglacial biodiversity, and mirror species-specific patterns of mammalian extinction during the Late Pleistocene. Herbivores experienced significantly greater declines than carnivores, revealing an important historical extinction filter that informs our understanding of relative resilience and vulnerability to human pressures for different taxa. We highlight the importance of large-scale, long-term datasets for understanding complex protracted extinction processes, although the dynamic pattern of progressive faunal depletion of European mammal assemblages across the Holocene challenges easy identification of ‘static’ past baselines to inform current-day environmental management and restoration.
Social learning in nest-building birds: a role for familiarity
Authors: Guillette Lauren M. , Scott Alice C. Y. , Healy Susan D.
Published: March 2016

It is becoming apparent that birds learn from their own experiences of nest building. What is not clear is whether birds can learn from watching conspecifics build. As social learning allows an animal to gain information without engaging in costly trial-and-error learning, first-time builders should exploit the successful habits of experienced builders. We presented first-time nest-building male zebra finches with either a familiar or an unfamiliar conspecific male building with material of a colour the observer did not like. When given the opportunity to build, males that had watched a familiar male build switched their material preference to that used by the familiar male. Males that observed unfamiliar birds did not. Thus, first-time nest builders use social information and copy the nest material choices when demonstrators are familiar but not when they are strangers. The relationships between individuals therefore influence how nest-building expertise is socially transmitted in zebra finches.
Mixture model of pottery decorations from Lake Chad Basin archaeological sites reveals ancient segregation patterns
Authors: O'Brien John D. , Lin Kathryn , MacEachern Scott
Published: March 2016

We present a new statistical approach to analysing an extremely common archaeological data type—potsherds—that infers the structure of cultural relationships across a set of excavation units (EUs). This method, applied to data from a set of complex, culturally heterogeneous sites around the Mandara mountains in the Lake Chad Basin, helps elucidate cultural succession through the Neolithic and Iron Age. We show how the approach can be integrated with radiocarbon dates to provide detailed portraits of cultural dynamics and deposition patterns within single EUs. In this context, the analysis supports ancient cultural segregation analogous to historical ethnolinguistic patterning in the region. We conclude with a discussion of the many possible model extensions using other archaeological data types.
Antagonistic coevolution between quantitative and Mendelian traits
Authors: Yamamichi Masato , Ellner Stephen P.
Published: March 2016

Coevolution is relentlessly creating and maintaining biodiversity and therefore has been a central topic in evolutionary biology. Previous theoretical studies have mostly considered coevolution between genetically symmetric traits (i.e. coevolution between two continuous quantitative traits or two discrete Mendelian traits). However, recent empirical evidence indicates that coevolution can occur between genetically asymmetric traits (e.g. between quantitative and Mendelian traits). We examine consequences of antagonistic coevolution mediated by a quantitative predator trait and a Mendelian prey trait, such that predation is more intense with decreased phenotypic distance between their traits (phenotype matching). This antagonistic coevolution produces a complex pattern of bifurcations with bistability (initial state dependence) in a two-dimensional model for trait coevolution. Furthermore, with eco-evolutionary dynamics (so that the trait evolution affects predator–prey population dynamics), we find that coevolution can cause rich dynamics including anti-phase cycles, in-phase cycles, chaotic dynamics and deterministic predator extinction. Predator extinction is more likely to occur when the prey trait exhibits complete dominance rather than semidominance and when the predator trait evolves very rapidly. Our study illustrates how recognizing the genetic architectures of interacting ecological traits can be essential for understanding the population and evolutionary dynamics of coevolving species.
Adaptive tolerance to a pathogenic fungus drives major histocompatibility complex evolution in natural amphibian populations
Authors: Savage Anna E. , Zamudio Kelly R.
Published: March 2016

Amphibians have been affected globally by the disease chytridiomycosis, caused by the fungusBatrachochytrium dendrobatidis(Bd), and we are just now beginning to understand how immunogenetic variability contributes to disease susceptibility. Lineages of an expressed major histocompatibility complex (MHC) class II locus involved in acquired immunity are associated with chytridiomycosis susceptibility in controlled laboratory challenge assays. Here, we extend these findings to natural populations that vary both in exposure and response toBd. We find that MHC alleles and supertypes associated withBdsurvival in the field show a molecular signal of positive selection, while those associated with susceptibility do not, supporting the hypothesis that heritableBdtolerance is rapidly evolving. We compare MHC supertypes to neutral loci to demonstrate where selection versus demography is shaping MHC variability. One population withBdtolerance in nature shows a significant signal of directional selection for the same allele (allele Q) that was significantly associated with survival in an earlier laboratory study. Our findings indicate that selective pressure forBdsurvival drives rapid immunogenetic adaptation in some natural populations, despite differences in environment and demography. Our field-based analysis of immunogenetic variation confirms that natural amphibian populations have the evolutionary potential to adapt to chytridiomycosis.
A trail camera imagery dataset of contrasting shrub and open microsites within the Carrizo Plain National Monument, San Luis Obispo County, California
Authors: Noble Taylor J. , Lortie Christopher J. , Westphal Michael , Butterfield H. Scott
Published: March 2016

Background

Carrizo Plain National Monument is one of the largest remaining patches of San Joaquin Desert left within the Central Valley of California. It is home to many threatened and endangered species including the San Joaquin kit fox, blunt-nosed leopard lizard, and giant kangaroo rat. The dominant plant lifeform is shrubs. The speciesEphedra californicacomprises a major proportion of the community within this region and likely also provides key ecosystem services. We used motion sensor trail cameras to examine interactions between animals and these shrubs. This technology is a less invasive alternative to other animal surveying methods such as line transects, radio tracking, and spotlight surveys. Cameras were placed within the shrub understory and in the open (i.e. non-canopied) microhabitats at ground level to estimate animal activity.

Findings

Trail cameras were successful in detecting the presence of animal species at shrub and open microhabitats. A total of 20 cameras were deployed from April 1st, 2015 to July 5th, 2015 at paired shrub/open microsites at three locations along Elkhorn Road in Carrizo Plain National Monument (35.1914° N, 119.7929° W). Each independent site was approximately 1 km2. Over 440,000 pictures (both of animals and triggers from vegetation moving in the wind) were taken during this time. The trigger rate was very high on the medium sensitivity camera setting in this desert ecosystem, and the rates did not differ between shrub and open microsites. The raw data (.jpeg images) are publicly available for download from GigaDB.

Conclusions

Motion sensor trail cameras are an effective, non-invasive alternative survey method for collecting data on presence/absence of desert animals. We detected mammals, reptiles, birds, and also insects in 0.4% of the images. We also successfully detected the Federally-listed blunt-nosed leopard lizard. A more extensive array of cameras within the Carrizo Plain National Monument could thus be an effective tool to estimate the presence of this species along with the presence of other animals.
In-vivo mutation rates and fitness landscape of HIV-1
Authors: Zanini Fabio , Puller Vadim , Brodin Johanna , Albert Jan , Neher Richard
Published: March 2016

Mutation rates and fitness costs of deleterious mutations are difficult to measurein vivobut essential for a quantitative understanding of evolution. Using whole genome deep sequencing data from longitudinal samples during untreated HIV-1 infection, we estimated mutation rates and fitness costs in HIV-1 from the temporal dynamics of genetic variation. At approximately neutral sites, mutations accumulate with a rate of 1.2 x 10-5per site per day, in agreement with the rate measured in cell cultures. The rate from G to A is largest, followed by the other transitions C to T, T to C, and A to G, while transversions are more rare. At non-neutral sites, most mutations reduce virus replication; using a model of mutation selection balance, we estimated the fitness cost of mutations at every site in the HIV-1 genome. About half of all nonsynonymous mutations have large fitness costs (greater than 10%), while most synonymous mutations have costs below 1%. The cost of synonymous mutations is especially low in most of gag and pol, while much higher costs are observed in important RNA structures and regulatory regions. The intrapatient fitness cost estimates are consistent across multiple patients, suggesting that the deleterious part of the fitness landscape is universal and explains a large fraction of global HIV-1 group M diversity.
DrosophilaMutants that Are Motile but Respond Poorly to All Stimuli Tested
Authors: Vang Lar L. , Adler Julius
Published: March 2016

AdultDrosophila melanogasterfruit flies were placed into one end of a tube near to repellents (benzaldehyde and heat) and away from the other end containing attractants (light and a favored temperature). They escaped from the repellents and went to the attractants. Five motile mutants that failed to do that were isolated. They did not respond to any external attractants tested or external repellents tested. In addition, they did not respond well to internal sensory stimuli like hunger, thirst, and sleep. The mutants, although motile, failed to respond to stimuli at both 34°C and at room temperature. Some of the mutants have been mapped. It is proposed that the information from the different sensory receptors comes together at an intermediate, called “inbetween” (Inbet), that brings about a behavioral response. The Boss is defined here.
Signatures of archaic adaptive introgression in present-day human populations
Authors: Racimo Fernando , Marnetto Davide , Huerta-Sánchez Emilia
Published: March 2016

Comparisons of DNA from archaic and modern humans show that these groups interbred, and in some cases received an evolutionary advantage from doing so. This process - adaptive introgression - may lead to a faster rate of adaptation than is predicted from models with mutation and selection alone. Within the last couple of years, a series of studies have identified regions of the genome that are likely examples of adaptive introgression. In many cases, once a region was ascertained as being introgressed, commonly used statistics based on both haplotype as well as allele frequency information were employed to test for positive selection. Introgression by itself, however, changes both the haplotype structure and the distribution of allele frequencies, thus confounding traditional tests for detecting positive selection. Therefore, patterns generated by introgression alone may lead to false inferences of positive selection. Here we explore models involving both introgression and positive selection to investigate the behavior of various statistics under adaptive introgression. In particular, we find that the number and allelic frequencies of sites that are uniquely shared between archaic humans and specific present-day populations are particularly useful for detecting adaptive introgression. We then examine the 1000 Genomes dataset to characterize the landscape of uniquely shared archaic alleles in human populations. Finally, we identify regions that were likely subject to adaptive introgression and discuss some of the most promising candidate genes located in these regions.
Exploring the phenotypic consequences of tissue specific gene expression variation inferred from GWAS summary statistics
Authors: Barbeira Alvaro N. , Dickinson Scott P. , Torres Jason M. , Zheng Jiamao , Torstenson Eric S. , Wheeler Heather E. , Shah Kaanan P. , Bonazzola Rodrigo , Garcia Tzintzuni , Edwards Todd ,   GTEx Consortium, Nicolae Dan L. , Cox Nancy J. , Im Hae Kyung
Published: March 2016

Scalable, integrative methods to understand mechanisms that link genetic variants with phenotypes are needed. Here we derive a mathematical expression to compute PrediXcan (a gene mapping approach) results using summary data (S-PrediXcan) and show its accuracy and general robustness to misspecified reference sets. We apply this framework to 44 GTEx tissues and 100+ phenotypes from GWAS and meta-analysis studies, creating a growing public catalog of associations that seeks to capture the effects of gene expression variation on human phenotypes. Replication in an independent cohort is shown. Most of the associations were tissue specific, suggesting context specificity of the trait etiology. Colocalized significant associations in unexpected tissues underscore the need for an agnostic scanning of multiple contexts to improve our ability to detect causal regulatory mechanisms. Monogenic disease genes are enriched among significant associations for related traits, suggesting that smaller alterations of these genes may cause a spectrum of milder phenotypes.
The behaviour of hoverfly larvae (Diptera, Syrphidae) lessens the effects of floral subsidy in agricultural landscapes
Authors: Laubertie Elsa A. , Wratten Steve D. , Magro Alexandra , Hemptinne Jean-Louis
Published: March 2016

Modern agricultural landscapes favour crop pests: herbivores benefit from resource concentration and/or the absence of natural enemies in large areas of intensively farmed fields interspersed by small fragments of natural or non-crop habitats.

Conservation biological control (CBC) aims at increasing the functional diversity of agricultural landscapes to make them more hospitable to natural enemies, and less to herbivores. Although natural enemies readily respond to this management, very few studies assess if they succeed in effectively protecting crops.

We set up a field experiment to study if an ecological infrastructure varying in size and consisting of the provision of floral resources at the centre of lettuce plots would influence the number of eggs laid by hoverflies, and ultimately the control of lettuce aphids. We found that the hoverfly females lay more eggs in the plots with the larger flower resource compared to the control. However, this response had no impact on the abundance of aphids on the lettuces.

We designed two laboratory experiments to understand this absence of response. We found mutual interference between hoverfly larvae, and suggest it may undermine the biological control of aphids.

This mismatch between landscape management and the response of hoverflies indicates CBC should take into account insect behaviour, particularly their response to conspecific density, additionally to landscape ecology.
Single cell chemotactic responses ofHelicobacter pylorito urea in a microfluidic chip
Authors: Weng Xuan , Neethirajan Suresh , Vogt Adam
Published: March 2016

Helicobacter pyloriis a spiral-shaped bacterium that grows in the human digestive tract; it infects ~50% of the global population.H. pyloriinduce inflammation, gastroenteritis, and ulcers, which is associated with significant morbidity and may be linked to stomach cancer in certain individuals. Motility is an essential virulence factor forH. pylori, allowing it to migrate toward and invade the epithelial lining of the stomach to shelter it from the harsh environment of the stomach.H. pylorisenses pH gradients and use polar flagella to move towards the epithelium where the pH approaches neutrality. However, its chemotaxis behaviors are incompletely understood. Previous in vitro tests examining the response ofH. pylorito chemical gradients have been subjected to substantial limitations. To more accurately mimic/modulate the cellular microenvironment, a nanoporous microfluidic device was used to monitor the real time chemotactic activity of single cell ofH. pyloriin response to urea. The results showed that microfluidic method is a promising alternative for precisely studying chemotactic behavior of bacteria.
Laue diffraction behaviour in silver mosaic crystals at several gamma-ray energies and orientations
Authors: Wade Colin , Barrière Nicolas , Hanlon Lorraine , Bastie Pierre , Fitzpatrick Gerard , Jentschel Michael , Roudil Gilles , Von Ballmoos Peter
Published: March 2016

The Laue lens is an emerging technology that uses crystal diffraction to concentrate gamma-rays. The Darwin model describes diffraction in mosaic crystals at high energies (>50 keV) and is the basis for assessing the throughput of a Laue lens. While the Darwin model has been used successfully to describe binary alloys, it has shown inconsistencies when applied to diffraction with pure-metal crystals. This paper presents a systematic study of diffraction in pure-metal silver mosaic crystals and the performance of the Darwin model when applied to the data. Two cut silver crystals were tested at the Institute Laue–Langevin facility at three gamma-ray energies and at three different crystallographic orientations. The rocking curves were fitted using the Darwin model. A single Gaussian for the distribution of crystallite orientations leads to poor quality fits. A crystallite distribution that is the sum of two Gaussians gives improved fits. However, for each crystal, the Darwin model gives mosaicities and crystallite sizes that are not consistent with one another as a function either of energy or of crystallographic orientation, despite these being physical properties of the materials. Without an adequate model to describe diffraction in pure-metal crystals, either a Laue lens design must severely limit its catalogue of usable materials or each crystal in the design must be tested at the exact energy at which it is to be used. A more general theory to describe hard X-ray diffraction using pure-metal mosaic crystals, possibly involving a distribution of crystallite sizes, is therefore required.
The phase diagram of K0.5Na0.5NbO3–Bi1/2Na1/2TiO3
Authors: Liu Laijun , Knapp Michael , Ehrenberg Helmut , Fang Liang , Schmitt Ljubomira Ana , Fuess Hartmut , Hoelzel Markus , Hinterstein Manuel
Published: March 2016

The phase diagram of the lead-free piezoelectric (1 − x)K0.5Na0.5NbO3–xBi1/2Na1/2TiO3 system has been studied by high-resolution synchrotron powder diffraction, neutron powder diffraction and selected area electron diffraction. The two lead-free piezoelectric materials K0.5Na0.5NbO3 and Bi1/2Na1/2TiO3 form an infinite substitution solid solution. The orthorhombic (O), monoclinic (M), tetragonal (T) and rhombohedral (R) phases and the phase coexistence of M (Pm) + T (P4mm) for 0.02 < x ≤ 0.14, T (P4bm) + pseudocubic (Pm{\overline 3}m) for 0.14 < x ≤ 0.87 and T (P4bm) + R (R3c) for 0.87 < x ≤ 0.96 have been investigated at room temperature, with a subtle change in the structure observed. The oxygen octahedral tilt system has been mapped as a function of composition and temperature. The results indicate that K0.5Na0.5NbO3–Bi1/2Na1/2TiO3 does not display a morphotropic phase boundary like lead zirconate titanate, and that the most significant structural changes as a function of composition occur near x = 0.14 and x = 0.87 as a result of ionic disorder at the A and B sites in the perovskite ABO3 structure at room temperature.
Identifying and quantifying amorphous and crystalline content in complex powdered samples: application to archaeological carbon blacks
Authors: Cersoy Sophie , Martinetto Pauline , Bordet Pierre , Hodeau Jean Louis , Van Elslande Elsa , Walter Philippe
Published: March 2016

Carbon black materials have been frequently used from prehistory as pigments for drawings and paintings and also as dyes, inks and cosmetics, since they are easy to make by burning organic matter. However, the carbonaceous phases they form are often ill-ordered and not easy to characterize. Five carbon black Roman micro samples found in vessels in houses in Pompeii were studied. These precious powders correspond to mixed phase samples that contain both crystalline and ill-ordered components. Here, a methodological approach that accomplishes the identification, quantification and mapping of the different phases in these heterogeneous samples using synchrotron-based techniques is proposed. The results were compared with those from scanning electron microscopy. Information about the nature of the mixtures and the origin of carbon black pigments is obtained. The use of charred vegetable materials is concluded, independently of the shape and the nature of the container.
Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources
Authors: Rutherford Michael E. , Chapman David J. , White Thomas G. , Drakopoulos Michael , Rack Alexander , Eakins Daniel E.
Published: March 2016

The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits).
Applications of thin-film sandwich crystallization platforms
Authors: Axford Danny , Aller Pierre , Sanchez-Weatherby Juan , Sandy James
Published: March 2016

Examples are shown of protein crystallization in, and data collection from, solutions sandwiched between thin polymer films using vapour-diffusion and batch methods. The crystallization platform is optimal for both visualization andin situdata collection, with the need for traditional harvesting being eliminated. In wells constructed from the thinnest plastic and with a minimum of aqueous liquid, flash-cooling to 100 K is possible without significant ice formation and without any degradation in crystal quality. The approach is simple; it utilizes low-cost consumables but yields high-quality data with minimal sample intervention and, with the very low levels of background X-ray scatter that are observed, is optimal for microcrystals.
Automated harvesting and processing of protein crystals through laser photoablation
Authors: Zander Ulrich , Hoffmann Guillaume , Cornaciu Irina , Marquette Jean-Pierre , Papp Gergely , Landret Christophe , Seroul Gaël , Sinoir Jérémy , Röwer Martin , Felisaz Frank , Rodriguez-Puente Sonia , Mariaule Vincent , Murphy Peter , Mathieu Magali , Cipriani Florent , Márquez José Antonio
Published: March 2016

Currently, macromolecular crystallography projects often require the use of highly automated facilities for crystallization and X-ray data collection. However, crystal harvesting and processing largely depend on manual operations. Here, a series of new methods are presented based on the use of a low X-ray-background film as a crystallization support and a photoablation laser that enable the automation of major operations required for the preparation of crystals for X-ray diffraction experiments. In this approach, the controlled removal of the mother liquor before crystal mounting simplifies the cryocooling process, in many cases eliminating the use of cryoprotectant agents, while crystal-soaking experiments are performed through diffusion, precluding the need for repeated sample-recovery and transfer operations. Moreover, the high-precision laser enables new mounting strategies that are not accessible through other methods. This approach bridges an important gap in automation and can contribute to expanding the capabilities of modern macromolecular crystallography facilities.
Grappling with anisotropic data, pseudo-merohedral twinning and pseudo-translational noncrystallographic symmetry: a case study involving pyruvate kinase
Authors: Donovan Katherine A. , Atkinson Sarah C. , Kessans Sarah A. , Peng Fen , Cooper Tim F. , Griffin Michael D. W. , Jameson Geoffrey B. , Dobson Renwick C. J.
Published: March 2016

Pyruvate kinase is a key regulatory enzyme involved in the glycolytic pathway. The crystal structure ofEscherichia colitype I pyruvate kinase was first solved in 1995 at 2.5 Å resolution. However, the space group was ambiguous, being either primitive orthorhombic (P212121) orC-centred orthorhombic (C2221). Here, the structure determination and refinement ofE. colitype I pyruvate kinase to 2.28 Å resolution are presented. Using the same crystallization conditions as reported previously, the enzyme was found to crystallize in space groupP21. Determination of the space group was complicated owing to anisotropic data, pseudo-translational noncrystallographic symmetry and the pseudo-merohedrally twinned nature of the crystal, which was found to have very close to 50% twinning, leading to apparent orthorhombic symmetry and absences that were not inconsistent withP212121. The unit cell contained two tetramers in the asymmetric unit (3720 residues) and, when compared with the orthorhombic structure, virtually all of the residues could be easily modelled into the density. Averaging of reflections into the lower symmetry space group with twinning provided tidier electron density that allowed ∼30 missing residues of the lid domain to be modelled for the first time. Moreover, residues in a flexible loop could be modelled and sulfate molecules are found in the allosteric binding domain, identifying the pocket that binds the allosteric activator fructose 1,6-bisphosphate in this isozyme for the first time. Lastly, we note the pedagogical benefits of difficult structures to emerging crystallographers.
Managing adaptive orientation systems for museum visitors from an IoT perspective
Authors: Solima Ludovico , Della Peruta Maria Rosaria , Maggioni Vincenzo
Published: March 2016

Purpose

– Starting from the premises that Internet of Things (IoT) applications can be used in museums as an aid to visiting systems, the purpose of this paper is to see how recommendation systems can be developed to provide advanced services to museum visitors.

Design/methodology/approach

– The research methodology employs a qualitative exploratory multi-case study: the method used has consisted in crossing the information currently known on the most advanced communication technologies (ICT) with the requirements of enhancing museum services, in order to determine the possible trajectories of applying the former to the latter.

Findings

– The implementation of recommender system outlines the main implications and effects of an advanced market-driven digital orientation, as the system’s users are the starting point for innovation and the creation of value. For a museum, it will be possible to access to an additional system of knowledge alongside that of its scientific staff. This process has profound implications in the way in which a museum presents itself and how it is perceived by its visitors and, in a wider sense, by the potential demand.

Research limitations/implications

– The paper consists in an exploratory effort to introduce an analytical framework for an evolved adaptive museum orientation system; the empirical investigation can be structured in the inductive-predictive view of assessing this promising debate further.

Originality/value

– Implementing the IoT blueprint entails introducing a plethora of new products, services and business models, opening new routes to guide and direct cultural events. Now, more than ever, sustainable development involves an intrinsic balancing act between the pluralism of data and that of customer needs, which is achieved through the elaboration of digital data.
The bank of things
Authors: Del Giudice Manlio , Campanella Francesco , Dezi Luca
Published: March 2016

Purpose

– The purpose of this paper is to study the existing relationship between the products offered by the banks of things and the relative return on equity (ROE). This can be used to highlight the benefit of carrying out investments to transform traditional banks into banks of things.

Design/methodology/approach

– The sample used in this empirical research contained 3,692 banks that, in 2013, were located in 28 European countries. To determine whether the Internet of Things (IoT) has an effect on the banks’ profitability, the authors employed the classification analysis method (classification and regression tree).

Findings

– The empirical analysis shows that a high ROE for banks is expressed by the following features: first, banks offer IoT retail services to customers; second, banks offer IoT corporate services to customers; third, banks offer customers a large number of home banking services; and finally, banks offer customers a large number of traditional investment services.

Research limitations/implications

– The survey covers a sample of European banks. It would be necessary to extend the sample to other geographical areas. It would be possible to generalize the results.

Originality/value

– Scientific research on the implications of the “Bank of things” are still few and fragmented.
The effects of old-age stereotypes on organizational productivity (part one)
Authors: Appelbaum Steven H. , Wenger Richard , Pachon Buitrago Carolina , Kaur Ravneet
Published: March 2016

Purpose

– The purpose of this paper is to examine common stereotypes regarding old-age workers and the effect of these stereotypes on organizational productivity, as well as to suggest practical solutions for accommodating old-age workers and increasing productivity in all employees.

Design/methodology/approach

– This three part paper will present a thorough review of relevant literature (1991-2014, with the exception of two studies from 1976) that were conducted on the topics of old-age stereotyping, the effect of old-age stereotyping on organizational productivity, and methods for adequately motivating and managing old-age workers. Studies concerning psychology theories are also examined in order to provide a framework for practical solutions, as well as demographic statistics on population age and employment trends.

Findings

– This paper identifies a number of old-age stereotypes that have decreased organizational productivity in empirical studies, including reluctance to change, decreased learning ability, intelligence and memory, poor health and accidents, higher organizational costs, decreased motivation, and low innovation and productivity. Findings also suggest that old-age workers can positively affect productivity, and that low productivity is often a result of stereotyping.

Research limitations/implications

– The prevalence of old-age stereotyping and its impact on organizational productivity may differ by culture, industry, type of employment, education level, and other factors, and thus further research may be necessary. The literature reviewed may not adequately represent worldwide organizational trends, as the literature is largely comprised of studies performed in North America and Europe.

Practical implications

– Solutions based on these findings are taken directly from the literature or derived from literature on psychology theories, which include self-determination theory, socio-emotional selectivity theory, and selective optimization and compensation theory. The practical solutions proposed address work environment, motivation, rewards, flexibility, and the loss and gain of resources in old-age workers.

Social implications

– The proportion of old-age workers is increasing and it is therefore necessary to determine ways to adequately integrate old-age workers in the workforce. Furthermore, this can raise productivity in all employees.

Originality/value

– This paper demonstrates that old-age stereotyping is both prevalent and detrimental within an organizational context. These findings and solutions can potentially be used by organizations in order to increase individual and overall productivity.
Factors influencing logistics cost and service quality: a survey within the Indian steel sector
Authors: Jena N , Seth Nitin
Published: March 2016

Purpose

– The purpose of this paper is to understand the role of economic and social factors influencing the logistics cost for the Indian steel sector and its relationship with the service quality.

Design/methodology/approach

– A structured questionnaire survey is used for the data collection in this research. The questionnaire included different elements of logistics cost on inbound and outbound logistics, and service quality.

Findings

– This research identified various significant elements of logistics cost for Indian steel sector and observed its relationship with transportation cost, warehousing cost and administrative cost. The findings of this study showed positive relationship between logistics cost and service quality.

Research limitations/implications

– The data for this study is cross-sectional; it is recommended that future studies can gather it longitudinally. This will help in gaining deeper understanding of the cause and effect relationship among the variables. The findings of this study are very useful in identifying the suitable training directions.

Practical implications

– Logistics is very critical factor in deciding the competitiveness of steel sector globally. Particularly for steel manufacturing the inbound logistics is more critical as compared to outbound logistics both in terms of volumes and costs.

Social implications

– For the Indian steel manufacturing companies, the logistics cost is very high as compared to other developed countries. Total logistics cost on inbound movements taken into consideration is around 16-18 per cent of material turn-over whereas; the world average is around 7-8 per cent.

Originality/value

– To the best knowledge of the authors, this study is the first attempt to study the relationship of logistics cost elements on the service quality in the context of Indian steel manufacturing sector. The logistics cost in steel industry is considered as one of the top performance measurement of the entrepreneur in this research.
The need for global leadership
Authors: Bernard-Stevens David
Published: March 2016

Purpose

– The purpose of this paper is to get individuals understanding how to think differently about leadership and the process for creating ethical leaders with sustainable impact.

Design/methodology/approach

– The author uses his experience as a teacher, a state senator and his own learning experiences from studying and experiencing leadership from the top down. The author has taken concepts from his recently published book: A Leap of Faith: Going, Doing and Changing Ourselves and the World Around Us.

Findings

– There is a huge difference between having a position of authority and that of being a leader. One cannot lead anyone until first learning to lead one’s self. That we must shift how we think from reacting and repeating to responding and creating new possibilities.

Research limitations/implications

– This work is based upon the life experiences of the author. It is limited to that experience and his interpretation of what those experiences can mean for future leaders.

Practical implications

– These concepts can change reality for anyone both professionally and personally. These are concepts for changing ourselves and the world around us to provide meaning and joy regardless of one’s circumstance.

Social implications

– Create a way of thinking and a process for creating authentic, ethical leaders throughout the world whose impact will be both sustainable and resilient in the worlds of today and tomorrow.

Originality/value

– These are concepts taken from the author’s new book which is in the form of letters to his sons (and to us) about his life, experiences and how to be ethical leaders with lives of meaning and joy.
Polish entrepreneurs in Glasgow and entrepreneurial opportunity structure
Authors: Lassalle Paul , McElwee Gerard
Published: March 2016

Purpose

– The purpose of this paper is to develop a modelized representation of the concept of opportunity structures for ethnic minority entrepreneurs in Glasgow, Scotland, that incorporates the different demand and supply side dimensions influencing entrepreneurial activity.

Design/methodology/approach

– An appropriate qualitative research design was implemented in order to capture and understand the influence of contextual dimensions on entrepreneurial behaviour of Polish EMEs in Glasgow. As part of the abductive and reflective process of the research, 21 semi-structured interviews were carried out in with Polish EMEs who are sole-owners of businesses.

Findings

– By contextualising ethnic minority entrepreneurship, the paper reveals the crucial and ambivalent role played by the community (for resource mobilisation and as the primary market) and by Polish EMEs’ perception of the opportunity structure, on their entrepreneurial behaviour. Moreover, it highlights the importance of the household as a contextual dimension on entrepreneurial decision making among those Polish entrepreneurs in Glasgow.

Practical implications

– Provides a comprehensive and operational model of opportunity structure for EMEs which can be used an operational tool for both scholars in the field as well as by policy makers. The proposed model constitutes a framework for analysing the influence of different contextual dimensions on EMEs’ entrepreneurial behaviour.

Originality/value

– The contribution is the provision of an original tool to enable further systematic comparative approaches while conducting research on EMEs across different communities and localities.
The social context for value co-creations in an entrepreneurial network
Authors: Ferguson Ronald , Schattke Kaspar , Paulin Michele
Published: March 2016

Purpose

– The purpose of this paper is to study micro-level research into the social dimensions of entrepreneurial partnerships assessed by the influences of: the degree of interpersonal attraction, the strength of relational norms and the level of partner trustworthiness on value co-creations in an emerging biotechnology network.

Design/methodology/approach

– Financial and scientific partnerships were investigated by structured interviews with entrepreneurs. Financial partnerships were also studied using interviews with lead investors. Research design and analyses were based on a Conditional Process Model.

Findings

– Partner trustworthiness was found to be critical for the co-creation of value in both types of partnerships. In financial partnerships, the level of interpersonal attraction and relational norms strength acted independently as antecedents of partner trustworthiness. Only the entrepreneur linked interpersonal attraction directly to value co-creation. Both entrepreneurs and lead investors perceived the association between interpersonal attraction and co-created value to be mediated through partner trustworthiness. Only the lead investor perceived this mediation to be moderated by relational norms strength. However, in scientific partnerships, relational norms strength, but not interpersonal attraction, contributed to partner trustworthiness that subsequently effected value co-creation. The entrepreneur’s trustworthiness perception in both types of partnerships was mainly due to a partner’s reputation, whereas for lead investors it was primarily the perceived reliability of the entrepreneur.

Originality/value

– This research points out the challenges of measurement and interpretation of network research. Theoretical conclusions based on only one partner’s perspective and in one context would not be sufficient to describe the complexity of value co-creations in entrepreneurial networks. Also, the cooperative social, rather than competitive opportunistic nature of entrepreneurial knowledge-intensive networks was confirmed.