bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural origins of coloration in the spiderPhoroncidia rubroargenteaBerland, 1913 (Araneae: Theridiidae) from Madagascar
Authors: Kariko Sarah , Timonen Jaakko V. I. , Weaver James C. , Gur Dvir , Marks Carolyn , Leiserowitz Leslie , Kolle Mathias , Li Ling
Published: February 2018

This study investigates the structural basis for the red, silver and black coloration of the theridiid spider,Phoroncidia rubroargentea(Berland, 1913) from Madagascar. Specimens of this species can retain their colour after storage in ethanol for decades, whereas most other brightly pigmented spider specimens fade under identical preservation conditions. Using correlative optical, structural and chemical analysis, we identify the colour-generating structural elements and characterize their optical properties. The prominent silvery appearance of the spider's abdomen results from regularly arranged guanine microplatelets, similar to those found in other spiders and fish. The microplatelets are composed of a doublet structure twinned about the [] axis, as suggested by electron diffraction. The red coloration originates from chambered microspheres (approx. 1 µm in diameter), which contain structured fluorescent material. Co-localization of the red microparticles on top of the reflective guanine microplatelets appears to enhance the red coloration. The spider's thick cuticular layer, which encases its abdomen, varies in its optical properties, being transparent in regions where only guanine reflectors are present, and tanned, exhibiting light absorption where the red microspheres are found. Moreover, colour degradation in some preserved spider specimens that had suffered damage to the cuticular layer suggests that this region of the exoskeleton may play an important role in the stabilization of the red coloration.
Swimming mechanics and propulsive efficiency in the chambered nautilus
Authors: Neil Thomas R. , Askew Graham N.
Published: February 2018

The chambered nautilus (Nautilus pompilius) encounters severe environmental hypoxia during diurnal vertical movements in the ocean. The metabolic cost of locomotion (Cmet) and swimming performance depend on how efficiently momentum is imparted to the water and how long on-board oxygen stores last. While propulsive efficiency is generally thought to be relatively low in jet propelled animals, the lowCmetinNautilusindicates that this is not the case. We measured the wake structure inNautilusduring jet propulsion swimming, to determine their propulsive efficiency. Animals swam with either an anterior-first or posterior-first orientation. With increasing swimming speed, whole cycle propulsive efficiency increased during posterior-first swimming but decreased during anterior-first swimming, reaching a maximum of 0.76. The highest propulsive efficiencies were achieved by using an asymmetrical contractile cycle in which the fluid ejection phase was relatively longer than the refilling phase, reducing the volume flow rate of the ejected fluid. Our results demonstrate that a relatively high whole cycle propulsive efficiency underlies the lowCmetinNautilus, representing a strategy to reduce the metabolic demands in an animal that spends a significant part of its daily life in a hypoxic environment.
Experimental and numerical investigations on spray characteristics of fatty acid methyl esters
Authors: Lanjekar R. D. , Deshmukh D.
Published: February 2018

A comparative experimental and numerical study is conducted to establish the significance of the use of single-component over multi-component representatives of biodiesel, diesel and their blend for predicting spray tip penetration. Methyl oleate and methyl laurate are used as single-component representative fuels for biodiesel. The pure components
n
-heptane,
n
-dodecane and
n
-tetradecane are used as single-component representative fuels for diesel. Methyl laurate is found to represent biodiesel of coconut, whereas methyl oleate is found to represent biodiesel having high percentage of long-chain fatty acid esters. The spray tip penetration of methyl oleate is found to be in good agreement with the measured spray tip penetration of karanja biodiesel. The spray tip penetration prediction of
n
-heptane fuel is closely following diesel spray tip penetration along with that of
n
-tetradecane and
n
-dodecane. The study suggests that the knowledge of the single-component representatives of biodiesel, diesel and their blend is sufficient to predict the spray tip penetration of the corresponding biodiesel, diesel and their blend under non-evaporating environment.
A method for estimating Hill function-based dynamic models of gene regulatory networks
Authors: Ehsan Elahi Faizan , Hasan Ammar
Published: February 2018

Gene regulatory networks (GRNs) are quite large and complex. To better understand and analyse GRNs, mathematical models are being employed. Different types of models, such as logical, continuous and stochastic models, can be used to describe GRNs. In this paper, we present a new approach to identify continuous models, because they are more suitable for large number of genes and quantitative analysis. One of the most promising techniques for identifying continuous models of GRNs is based on Hill functions and the generalized profiling method (GPM). The advantage of this approach is low computational cost and insensitivity to initial conditions. In the GPM, a constrained nonlinear optimization problem has to be solved that is usually underdetermined. In this paper, we propose a new optimization approach in which we reformulate the optimization problem such that constraints are embedded implicitly in the cost function. Moreover, we propose to split the unknown parameter in two sets based on the structure of Hill functions. These two sets are estimated separately to resolve the issue of the underdetermined problem. As a case study, we apply the proposed technique on the SOS response inEscherichia coliand compare the results with the existing literature.
Electrical, dielectric properties and study of AC electrical conduction mechanism of Li
0.9
□
0.1
NiV
0.5
P
0.5
O
4
Authors: Rahal A. , Borchani S. Megdiche , Guidara K. , Megdiche M. 
Published: February 2018

In this paper, we report the measurements of impedance spectroscopy for a new olivine-type lithium deficiency Li
0.9
□
0.1
NiV
0.5
P
0.5
O
4
compound. It was synthesized by the conventional solid-state technique. All the X-ray diffraction peaks of the compound are indexed, and it is found that the sample is well crystallized in orthorhombic olivine structure belonging to the space group
Pnma
. Conductivity and dielectric analyses of the sample are carried out at different temperatures and frequencies using the complex impedance spectroscopy technique. The electrical conductivity of Li
0.9
□
0.1
NiV
0.5
P
0.5
O
4
is higher than that of parent compound LiNiV
0.5
P
0.5
O
4
. Temperature dependence of the DC conductivity and modulus was found to obey the Arrhenius law. The obtained values of activation energy are different which confirms that transport in the title compound is not due to a simple hopping mechanism. To determine the conduction mechanism, the AC conductivity and its frequency exponent have been analysed in this work by a theoretical model based on quantum mechanical tunnelling: the non-overlapping small polaron tunnelling model.
Kinship underlies costly cooperation in Mosuo villages
Authors: Thomas Matthew Gwynfryn , Ji Ting , Wu Jiajia , He QiaoQiao , Tao Yi , Mace Ruth
Published: February 2018

The relative importance of social evolution theories such as kin selection, direct reciprocity and need-based transfers in explaining real-world cooperation is the source of much debate. Previous field studies of cooperation in human communities have revealed variability in the extent to which each of these theories explains human sociality in different contexts. We conducted multivariate social network analyses predicting costly cooperation—labouring on another household's farm—in 128 082 dyads of Mosuo farming households in southwest China. Through information-theoretic model selection, we tested the roles played by genealogical relatedness, affinal relationships (including reproductive partners), reciprocity, relative need, wealth, household size, spatial proximity and gift-giving in an economic game. The best-fitting model included all factors, along with interactions between relatedness and (i) reciprocity, (ii) need, (iii) the presence of own children in another household and (iv) proximity. Our results show how a real-world form of cooperation was driven by kinship. Households tended to help kin in need (but not needy non-kin) and travel further to help spatially distant relatives. Households were more likely to establish reciprocal relationships with distant relatives and non-kin but closer kin cooperated regardless of reciprocity. These patterns of kin-driven cooperation show the importance of inclusive fitness in understanding human social behaviour.
Online incidental statistical learning of audiovisual word sequences in adults: a registered report
Authors: Kuppuraj Sengottuvel , Duta Mihaela , Thompson Paul , Bishop Dorothy
Published: February 2018

Statistical learning has been proposed as a key mechanism in language learning. Our main goal was to examine whether adults are capable of simultaneously extracting statistical dependencies in a task where stimuli include a range of structures amenable to statistical learning within a single paradigm. We devised an online statistical learning task using real word auditory–picture sequences that vary in two dimensions: (i) predictability and (ii) adjacency of dependent elements. This task was followed by an offline recall task to probe learning of each sequence type. We registered three hypotheses with specific predictions. First, adults would extract regular patterns from continuous stream (effect of grammaticality). Second, within grammatical conditions, they would show differential speeding up for each condition as a factor of statistical complexity of the condition and exposure. Third, our novel approach to measure online statistical learning would be reliable in showing individual differences in statistical learning ability. Further, we explored the relation between statistical learning and a measure of verbal short-term memory (STM). Forty-two participants were tested and retested after an interval of at least 3 days on our novel statistical learning task. We analysed the reaction time data using a novel regression discontinuity approach. Consistent with prediction, participants showed a grammaticality effect, agreeing with the predicted order of difficulty for learning different statistical structures. Furthermore, a learning index from the task showed acceptable test–retest reliability (
r
 = 0.67). However, STM did not correlate with statistical learning. We discuss the findings noting the benefits of online measures in tracking the learning process.
Early development of vocal interaction rules in a duetting songbird
Authors: Rivera-Cáceres Karla D. , Quirós-Guerrero Esmeralda , Araya-Salas Marcelo , Templeton Christopher N. , Searcy William A.
Published: February 2018

Exchange of vocal signals is an important aspect of animal communication. Although birdsong is the premier model for understanding vocal development, the development of vocal interaction rules in birds and possible parallels to humans have been little studied. Many tropical songbirds engage in complex vocal interactions in the form of duets between mated pairs. In some species, duets show precise temporal coordination and follow rules (duet codes) governing which song type one bird uses to reply to each of the song types of its mate. We determined whether these duetting rules are acquired during early development in canebrake wrens. Results show that juveniles acquire a duet code by singing with a mated pair of adults and that juveniles gradually increase their fidelity to the code over time. Additionally, we found that juveniles exhibit poorer temporal coordination than adults and improve their coordination as time progresses. Human turn-taking, an analogous rule to temporal coordination, is learned during early development. We report that the ontogeny of vocal interaction rules in songbirds is analogous to that of human conversation rules.
Molecular evidence for the first records of facultative parthenogenesis in elapid snakes
Authors: Allen L. , Sanders K. L. , Thomson V. A.
Published: February 2018

Parthenogenesis is a form of asexual reproduction by which embryos develop from unfertilized eggs. Parthenogenesis occurs in reptiles; however, it is not yet known to occur in the widespread elapid snakes (Elapidae), which include well-known taxa such as cobras, mambas, taipans and sea snakes. Here, we describe the production of viable parthenogens in two species of Australo-Papuan elapids with divergent reproductive modes: the oviparous coastal/Papuan taipan (Oxyuranus scutellatus) and the viviparous southern death adder (Acanthophis antarcticus). Analyses of nuclear SNP data excluded paternity for putative fathers and convincingly demonstrated asexual reproduction, thus representing the first evidence of facultative parthenogenesis in Elapidae. Our finding has broad implications for understanding the evolution of reproductive diversity in snakes, as well as managing the conservation of genetic diversity in wild and captive populations.
Multiple benefits of alloparental care in a fluctuating environment
Authors: Guindre-Parker Sarah , Rubenstein Dustin R.
Published: February 2018

Although cooperatively breeding vertebrates occur disproportionately in unpredictable environments, the underlying mechanism shaping this biogeographic pattern remains unclear. Cooperative breeding may buffer against harsh conditions (hard life hypothesis), or additionally allow for sustained breeding under benign conditions (temporal variability hypothesis). To distinguish between the hard life and temporal variability hypotheses, we investigated whether the number of alloparents at a nest increased reproductive success or load-lightening in superb starlings (Lamprotornis superbus), and whether these two types of benefits varied in harsh and benign years. We found that mothers experienced both types of benefits consistent with the temporal variability hypothesis, as larger contingents of alloparents increased the number of young fledged while simultaneously allowing mothers to reduce their provisioning rates under both harsh and benign rainfall conditions. By contrast, fathers experienced load-lightening only under benign rainfall conditions, suggesting that cooperative breeding may serve to take advantage of unpredictable benign breeding seasons when they do occur. Cooperative breeding in unpredictable environments may thus promote flexibility in offspring care behaviour, which could mitigate variability in the cost of raising young. Our results highlight the importance of considering how offspring care decisions vary among breeding roles and across fluctuating environmental conditions.
Analysis and control of the dynamical response of a higher order drifting oscillator
Authors: Liu Yang , Páez Chávez Joseph , Pavlovskaia Ekaterina , Wiercigroch Marian
Published: February 2018

This paper studies a position feedback control strategy for controlling a higher order drifting oscillator which could be used in modelling vibro-impact drilling. Special attention is given to two control issues, eliminating bistability and suppressing chaos, which may cause inefficient and unstable drilling. Numerical continuation methods implemented via the continuation platform COCO are adopted to investigate the dynamical response of the system. Our analyses show that the proposed controller is capable of eliminating coexisting attractors and mitigating chaotic behaviour of the system, providing that its feedback control gain is chosen properly. Our investigations also reveal that, when the slider’s property modelling the drilled formation changes, the rate of penetration for the controlled drilling can be significantly improved.
Clownfishes evolution below and above the species level
Authors: Rolland Jonathan , Silvestro Daniele , Litsios Glenn , Faye Laurélène , Salamin Nicolas
Published: February 2018

The difference between rapid morphological evolutionary changes observed in populations and the long periods of stasis detected in the fossil record has raised a decade-long debate about the exact role played by intraspecific mechanisms at the interspecific level. Although they represent different scales of the same evolutionary process, micro- and macroevolution are rarely studied together and few empirical studies have compared the rates of evolution and the selective pressures between both scales. Here, we analyse morphological, genetic and ecological traits in clownfishes at different evolutionary scales and demonstrate that the tempo of molecular and morphological evolution at the species level can be, to some extent, predicted from parameters estimated below the species level, such as the effective population size or the rate of evolution within populations. We also show that similar codons in the gene of the rhodopsinRH1, a light-sensitive receptor protein, are under positive selection at the intra and interspecific scales, suggesting that similar selective pressures are acting at both levels.
Oldest known multituberculate stapes suggests an asymmetric bicrural pattern as ancestral for Multituberculata
Authors: Schultz Julia A. , Ruf Irina , Martin Thomas
Published: February 2018

Middle ear ossicles (malleus, incus, stapes) are known for few multituberculate taxa, and three different stapedial morphotypes have been suggested: (i) slender, columelliform and microperforate, (ii) robust and rod-like, and (iii) bicrural. Reinvestigation of Upper Jurassic (Kimmeridgian) mammalian petrosals from the Guimarota coal mine in central Portugal (Western Europe) revealed an asymmetric bicrural stapes (ABS) in the paulchoffatiid
Pseudobolodon oreas
. The middle ear ossicles displaced inside the osseous vestibule were detected by a µCT analysis. The Kimmeridgian age of the Guimarota stapes exceeds the stapes from the Early Cretaceous (Barremian) of Asia (about 122–124 Ma) by approximately 30 Myr, and is only slightly younger than the stapes of the recently described Oxfordian euharamiyidan
Arboroharamiya allinhopsoni
. The Guimarota stapes indicates that the stapes of
Lambdopsalis
, described as columelliform and microperforate (small stapedial foramen), does not represent a general condition for multituberculates. The stapes of
Pseudobolodon
is bicrural, the anterior crus sits centrally on the oval footplate, and the stapedial head is simple and smaller than the footplate. We hypothesize that the ABS evolved from the symmetric bicrural stapes (SBS) of non-mammaliaform cynodonts. The ABS appears to be the ancestral morphotype of the mammalian SBS, and the mammalian columelliform imperforate stapes.
Genome-wide analysis of adolescent psychotic experiences shows genetic overlap with psychiatric disorders
Authors: Pain Oliver , Dudbridge Frank , Cardno Alastair G. , Freeman Daniel , Lu Yi , Lundstrom Sebastian , Lichtenstein Paul , Ronald Angelica
Published: February 2018

This study aimed to test for overlap in genetic influences between psychotic experience traits shown by adolescents in the community, and clinically-recognized psychiatric disorders in adulthood, specifically schizophrenia, bipolar disorder, and major depression. The full spectra of psychotic experience domains, both in terms of their severity and type (positive, cognitive, and negative), were assessed using self- and parent-ratings in three European community samples aged 15-19 years (Final N incl. siblings = 6,297-10,098). A mega-genome-wide association study (mega-GWAS) for each psychotic experience domain was performed. SNP-heritability of each psychotic experience domain was estimated using genomic-relatedness-based restricted maximum-likelihood (GREML) and linkage disequilibrium-(LD-) score regression. Genetic overlap between specific psychotic experience domains and schizophrenia, bipolar disorder, and major depression was assessed using polygenic risk scoring (PRS) and LD-score regression. GREML returned SNP-heritability estimates of 3-9% for psychotic experience trait domains, with higher estimates for less skewed traits (Anhedonia, Cognitive Disorganization) than for more skewed traits (Paranoia and Hallucinations, Parent-rated Negative Symptoms). Mega-GWAS analysis identified one genome-wide significant association for Anhedonia within IDO2 but which did not replicate in an independent sample. PRS analysis revealed that the schizophrenia PRS significantly predicted all adolescent psychotic experience trait domains (Paranoia and Hallucinations only in non-zero scorers). The major depression PRS significantly predicted Anhedonia and Parent-rated Negative Symptoms in adolescence. Psychotic experiences during adolescence in the community show additive genetic effects and partly share genetic influences with clinically-recognized psychiatric disorders, specifically schizophrenia and major depression.
Targeting TrkB with a brain-derived neurotrophic factor mimetic promotes myelin repair in the brain
Authors: Fletcher Jessica L , Wood Rhiannon J , Nguyen Jacqueline , Norman Eleanor ML , Jun Christine MK , Prawdiuk Alexa R , Biemond Melissa , Nguyen Huynh TH , Northfield Susan E , Hughes Richard A , Gonsalvez David G , Xiao Junhua , Murray Simon S
Published: February 2018

Methods to promote myelin regeneration in response to central myelin loss are essential to prevent the progression of clinical disability in demyelinating diseases. The neurotrophin brain-derived neurotrophic factor (BDNF) is known to promote myelination during development via oligodendrocyte expressed TrkB receptors. Here, we use a structural mimetic of BDNF to promote myelin regeneration in a preclinical mouse model of central demyelination. We show that selective targeting of TrkB with the BDNF-mimetic enhances remyelination, increasing oligodendrocyte differentiation, the frequency of myelinated axons, and myelin sheath thickness after a demyelinating insult. Treatment with exogenous BDNF exerted an attenuated effect, increasing myelin sheath thickness only. Further, following conditional deletion of TrkB from pre-myelinating oligodendrocytes, we show the effects of the BDNF-mimetic on oligodendrocyte differentiation and remyelination are lost, indicating these are dependent on oligodendrocyte expression of TrkB. Overall, these studies demonstrate that targeting oligodendrocyte TrkB promotes in vivo remyelination in the brain.
Microtubule-associated protein IQ67 DOMAIN5 regulates interdigitation of leaf pavement cells inArabidopsis thaliana
Authors: Mitra Dipannita , Kumari Pratibha , Quegwer Jakob , Klemm Sandra , Möeller Birgit , Poeschl Yvonne , Pflug Paul , Stamm Gina , Abel Steffen , Bürstenbinder Katharina
Published: February 2018

Plant microtubules form a highly dynamic intracellular network with important roles for regulating cell division, cell proliferation and cell morphology. Its organization and dynamics are coordinated by various microtubule-associated proteins (MAPs) that integrate environmental and developmental stimuli to fine-tune and adjust cytoskeletal arrays. IQ67 DOMAIN (IQD) proteins recently emerged as a class of plant-specific MAPs with largely unknown functions. Here, using a reverse genetics approach, we characterize Arabidopsis IQD5 in terms of its expression domains, subcellular localization and biological functions. We show thatIQD5is expressed mostly in vegetative tissues, where it localizes to cortical microtubule arrays. Our phenotypic analysis ofiqd5loss-of-function lines reveals functions of IQD5 in pavement cell (PC) shape morphogenesis, as indicated by reduced interdigitation of neighboring cells in the leaf epidermis ofiqd5mutants. Histochemical analysis of cell wall composition further suggests reduced rates of cellulose deposition in anticlinal cell walls, which correlate with reduced asymmetric expansion. Lastly, we provide evidence for IQD5-dependent recruitment of calmodulin calcium sensors to cortical microtubule arrays. Our work thus identifies IQD5 as a novel player in PC shape regulation, and, for the first time, links calcium signaling to developmental processes that regulate multi-polar growth in PCs.

Highlight

Microtubule-localized Arabidopsis IQ67 DOMAIN5 regulates pavement cell morphogenesis in the leaf epidermis and links calcium-calmodulin signaling to lobe initiation and asymmetric expansion during early phases of interdigitated cell growth.
Highly efficient CRISPR/Cas9-mediated tissue specific mutagenesis inDrosophila
Authors: Poe Amy R. , Wang Bei , Sapar Maria L. , Ji Hui , Li Kailyn , Onabajo Tireniolu , Fazliyeva Rushaniya , Gibbs Mary , Qiu Yue , Hu Yuzhao , Han Chun
Published: February 2018

Tissue-specific loss-of-function (LOF) analysis is an essential approach for characterizing gene function. Here we describe an efficientCRISPR-mediatedtissue-restrictedmutagenesis (CRISPR-TRiM) method for ablating gene function inDrosophila. This binary system consists of a tissue-specific Cas9 and a ubiquitously expressed multi-guide RNA (gRNA) transgene. To facilitate the construction of these components, we developed convenient tools for generating and evaluating enhancer-driven Cas9 lines, identified a multi-gRNA design that is highly efficient in mutagenizing somatic cells, and established an assay for testing the efficiency of multi-gRNAs in creating double-stranded breaks. We found that excision of genomic DNA induced by two gRNAs is infrequent in somatic cells, while indels more reliably cause tissue-specific LOF. Furthermore, we show that enhancer-driven Cas9 is less cytotoxic yet results in more complete gene removal than Gal4-driven Cas9 in larval neurons. Finally, we demonstrate that CRISPR-TRiM efficiently unmasks redundant gene functions in neuronal morphogenesis. Importantly, two Cas9 transgenes that turn on with different timings in the neuronal lineage revealed the extent to which gene products persist in cells after tissue-specific gene knockout. These CRISRPR tools can be applied to analyze tissue-specific gene function in many biological processes.
Ancestral heterogeneity of ancient Eurasians
Authors: Shriner Daniel
Published: February 2018

Supervised clustering or projection analysis is a staple technique in population genetic analysis. The utility of this technique depends critically on the reference panel. The most commonly used reference panel in the analysis of ancient DNA to date is based on the Human Origins array. We previously described a larger reference panel that captures more ancestries on the global level. Here, we reanalyzed DNA data from 279 ancient Eurasians using our reference panel. We found substantially more ancestral heterogeneity than has been reported. Our reanalysis provides evidence against a resurgence of Western hunter-gatherer ancestry in the Middle to Late Neolithic and evidence for a common ancestor of farmers characterized by Western Asian ancestry, a transition of the spread of agriculture from demic to cultural diffusion, at least two migrations between the Pontic-Caspian steppes and Bronze Age Europe, and a sub-Saharan African component in Natufians that localizes to present-day southern Ethiopia.
Multisensory stimuli improve relative localisation judgments compared to unisensory auditory or visual stimuli
Authors: Freeman Laura , Wood Katherine C , Bizley Jennifer K
Published: February 2018

Observers performed a relative localisation task in which they reported whether the second of two sequentially presented signals occurred to the left or right of the first. Stimuli were detectability-matched auditory, visual, or auditory-visual signals and the goal was to compare changes in performance with eccentricity across modalities. Visual performance was superior to auditory at the midline, but inferior in the periphery, while auditory-visual performance exceeded both at all locations. No such advantage was seen when performance for auditory-only trials was contrasted with trials in which the first stimulus was auditory-visual and the second auditory only.
Active Learning of Cortical Connectivity from Two-Photon Imaging Data
Authors: Bertrán Martín , Martínez Natalia , Wang Ye , Dunson David , Sapiro Guillermo , Ringach Dario
Published: February 2018

Understanding how groups of neurons interact within a network is a fundamental question in system neuroscience. Instead of passively observing the ongoing activity of a network, we can typically perturb its activity, either by external sensory stimulation or directly via techniques such as two-photon optogenetics. A natural question is how to use such perturbations to identify the connectivity of the network efficiently. Here we introduce a method to infer sparse connectivity graphs fromin-vivo, two-photon imaging of population activity in response to external stimuli. A novel aspect of the work is the introduction of a recommended distribution, incrementally learned from the data, to optimally refine the inferred network.. Unlike existing system identification techniques, this “active learning” method automatically focuses its attention on key undiscovered areas of the network, instead of targeting global uncertainty indicators like parameter variance. We show how active learning leads to faster inference while, at the same time, provides confidence intervals for the network parameters. We present simulations on artificial small-world networks to validate the methods and apply the method to real data. Analysis of frequency of motifs recovered show that cortical networks are consistent with a small-world topology model.
Rapid nuclear exclusion of Hcm1 in agingSaccharomyces cerevisiaeleads to vacuolar alkalization and replicative senescence
Authors: Ghavidel Ata , Baxi Kunal , Prusinkiewicz Martin , Swan Cynthia , Belak Zach R. , Eskiw Christopher H. , Carvalho Carlos E. , Harkness Troy A.
Published: February 2018

Yeast cells, like other higher eukaryotic cells, undergo a finite number of cell divisions before exiting the cell cycle due to the effects of aging. Here, we show that yeast aging begins with the nuclear exclusion of Hcm1 in young cells, resulting in loss of acidic vacuoles. Autophagy is required for healthy aging in yeast, with proteins targeted for turnover by autophagy directed to the vacuole. Consistent with this, vacuolar acidity is necessary for vacuolar function and yeast longevity. Using yeast genetics and immunofluorescence microscopy, we confirm that vacuolar acidity plays a critical role in cell health and lifespan, and is potentially maintained by a series of Forkhead Box (Fox) transcription factors. An interconnected transcriptional network involving the Fox proteins (Fkh1, Fkh2 and Hcm1) are required for transcription of v-ATPase subunits and vacuolar acidity. As cells age, Hcm1 is rapidly excluded from the nucleus in young cells, blocking the expression of Hcm1 targets (Fkh1 and Fkh2), leading to loss of v-ATPase gene expression, reduced vacuolar acidification, increased α-syn-GFP vacuolar accumulation, and finally, diminished replicative lifespan (RLS). Loss of vacuolar acidity occurs about the same time as Hcm1 nuclear exclusion and is conserved; we have recently demonstrated that lysosomal alkalization similarly contributes to aging inC. elegansfollowing a transition from progeny producing to post-reproductive life. Our data points to a molecular mechanism regulating vacuolar acidity that signals the end of RLS when acidification is lost.
Intermolecular correlations are necessary to explain diffuse scattering from protein crystals
Authors: Peck Ariana , Poitevin Frédéric , Lane Thomas J.
Published: February 2018

Conformational changes drive protein function, including catalysis, allostery and signaling. X-ray diffuse scattering from protein crystals has frequently been cited as a probe of these correlated motions, with significant potential to advance our understanding of biological dynamics. However, recent work has challenged this prevailing view, suggesting instead that diffuse scattering primarily originates from rigid-body motions and could therefore be applied to improve structure determination. To investigate the nature of the disorder giving rise to diffuse scattering, and thus the potential applications of this signal, a diverse repertoire of disorder models was assessed for its ability to reproduce the diffuse signal reconstructed from three protein crystals. This comparison revealed that multiple models of intramolecular conformational dynamics, including ensemble models inferred from the Bragg data, could not explain the signal. Models of rigid-body or short-range liquid-like motions, in which dynamics are confined to the biological unit, showed modest agreement with the diffuse maps, but were unable to reproduce experimental features indicative of long-range correlations. Extending a model of liquid-like motions to include disorder across neighboring proteins in the crystal significantly improved agreement with all three systems and highlighted the contribution of intermolecular correlations to the observed signal. These findings anticipate a need to account for intermolecular disorder in order to advance the interpretation of diffuse scattering to either extract biological motions or aid structural inference.
Structure determination of phase II of the antifungal drug griseofulvin by powder X-ray diffraction
Authors: Mahieu Aurélien , Willart Jean-François , Guerain Mathieu , Derollez Patrick , Danéde Florence , Descamps Marc
Published: February 2018

Two new crystalline polymorphs of the widely used antifungal drug griseofulvin (phases II and III), which originate from the crystallization of the melt, have been detected recently. The crystal structure of phase II of griseofulvin {systematic name: (2S,6′R)-7-chloro-2′,4,6-trimethoxy-6′-methyl-3H,4′H-spiro[1-benzofuran-2,1′-cyclohex-2-ene]-3,4′-dione}, C17H17ClO6, has been solved by powder X-ray diffraction (PXRD). The PXRD pattern of this new phase was recorded at room temperature using synchrotron radiation. The starting structural model was generated by a Monte Carlo simulated annealing method. The final structure was obtained through Rietveld refinement with soft restraints for interatomic bond lengths and angles, except for the aromatic ring, where a rigid-body constraint was applied. The symmetry is orthorhombic (space groupP212121) and the asymmetric unit contains two molecules.
Understanding consumers’ purchase intention towards counterfeit luxury goods
Authors: Koay Kian Yeik
Published: February 2018

Purpose

Counterfeiting is a large business involving the manufacturing or distribution of imitation goods. The purpose of this paper is to develop an integrated research model that combines neutralisation theory and perceived risk theory to explain consumers’ purchase intention towards counterfeit luxury goods.

Design/methodology/approach

Of the 280 distributed questionnaires, 230 were returned. Rigorous data filtering was performed to remove problematic data, leaving 213 usable questionnaires for analysis. To validate the proposed hypotheses, PLS analysis (a variance-based structural equation modelling technique) was conducted using Smart-PLS.

Findings

The results showed that denial of responsibility, denial of victim, performance risk and social risk are significant predictors of consumers’ purchase intention towards counterfeit luxury goods. However, denial of injury, appeal to higher loyalties, condemnation of the condemners, as well as psychological risk and prosecution risks, were found to have no significant relationships with purchase intention towards counterfeit luxury goods.

Originality/value

The integrated model is useful in predicting consumers’ purchase intention towards counterfeit luxury goods. This study discusses the research findings and concludes with managerial implications and limitations.
The phenomenon of data loss and cyber security issues in Ghana
Authors: Adu Kofi Koranteng , Adjei Emmanuel
Published: February 2018

Purpose

This study aims to investigate the cyber security awareness and policies within corporate organisations in Ghana.

Design/methodology/approach

Using both quantitative and qualitative approaches underpinned by questionnaire and document analysis, data were collected from 100 participants centred on cyber security awareness and information policies.

Findings

The study underscored that, although corporate organisations had a good knowledge of IT, their awareness of cyber security remains limited. It observed that most organisations in Ghana are not integrating legal aspects into their information security policies. It proposed the need to increase the security awareness of corporate organisation, particularly because of the vulnerabilities they are exposed to.

Research limitations/implications

The implication of the paper with respect to theory, practice and future research lies in the recommendations the authors have proffered, such as the implementation of security awareness training programme, need assessment and the outsourcing of qualified service providers.

Practical implications

The study is useful for policy makers in the management of Ghana’s IT infrastructure.

Originality/value

This study is being undertaken at a period when Ghana has made progressive development and giant steps in the IT industry compared to its counterparts in sub-Saharan Africa. The developed nature of Ghana’s IT infrastructure requires the development of policies for cyber security to prevent data loses and protect the national infrastructure from threats. Undertaking a study on cyber security in an environment where cyber issues are hardly discussed is worthwhile.
The future of governance in Iran
Authors: Pourezzat Ali Asghar , Hoseini Moghadam Mohammad , Sani Ejlal Maryam , Taheriattar Ghazaleh
Published: February 2018

Purpose

Through an examination of macro-historical studies on the governance of Iran, the purpose of this study is to identify the most significant and important events and trends in the rise and fall of Iranian governments and introduce alternative futures in a range of possible, plausible and preferable forms of future governance. To carry out a foresight study of alternative futures of Iranian governance, the authors used futures studies, based on the detection of the most critical driving forces, which are also the most important uncertainties. Futures studies as an interdisciplinary field of study help to identify the events and trends that affect political change and offer scenarios of four alternative futures for the governance of Iran: Smart and Stable Government, Authoritarian Development-oriented Government, Irrational Government and Irrational Breakable Government. The authors believe that Iran’s endeavors to promote democracy, taking the changing international trends into account, make a more trustworthy future for Iran both possible plausible.

Design/methodology/approach

Based on macro-history approach and by using “shared history”, future triangle and then scenario planning, the future of Governance in Iran has been analyzed.

Findings

Whenever the government has distanced itself from the public and has neglected the trend of international change, it has been faced with a period of collapse and annihilation. And whenever these two important factors are understood, the result is a trend of development and growth. Therefore, the most favored image of Iran’s future relies on the maintenance and promotion of public participation and on increasing attention to the sustainable realities of international relations.

Originality/value

The complexities of events and trends affecting the rise and fall of previous governments of Iran make it necessary to use an interdisciplinary approach to understand the events that have emerged or are emerging in its governance. In this study, from futures studies point of view, transformation of governance has been studied.
Drivers and barriers towards re-using open government data (OGD): a case study of open data initiative in Oman
Authors: Saxena Stuti
Published: February 2018

Purpose

The purpose of this study is to underscore the significance, drivers and barriers towards re-use of open data sets in the context of Oman’s open government data (OGD) initiative.

Design/methodology/approach

Following a qualitative framework, the paper invoked a documentary analysis approach to probe the OGD initiative of Oman. Specifically, the national OGD portal of Oman (https://data.gov.om/) is being investigated in the paper. Furthermore, the paper invokes a theoretical model of “citizen engagement” (“Data over the wall”, “Code exchange”, “Civic issue tracker” and “Participatory open data model”) proposed by Sieber and Johnson (2015) to assess the extent to which open data sets may be re-used.

Findings

As per the theoretical model forwarded by Sieber and Johnson (2015), the OGD initiative of Oman is a cusp between “Data over the wall”, “Code exchange” and “Participatory” models. Oman’s OGD initiative facilitates the re-use of the open data sets. However, there are challenges in re-using the open data sets as well. The paper underlines the prospects of better re-use of data sets by institutionalizing the OGD initiative across all administrative levels of the country.

Practical implications

This study holds relevance for practitioners and policy-makers in Oman to ensure the re-use of data sets is facilitated for generating public value.

Originality/value

Hitherto, research has underlined the significance of launching OGD initiatives in the West but studies in developing countries are few. The present study seeks to plug this research gap by underlining the significance of OGD re-usage in Oman’s context.
Trade liberalization and gender inequality: role of social norms
Authors: Mukhopadhyay Ujjaini
Published: February 2018

Purpose

The purpose of this paper is to examine the effects of trade liberalization on gender earning differentials and female labour force participation by considering the interaction between changes in relative wages, intra-household bargaining power and social norms.

Design/methodology/approach

A three-sector general equilibrium model is developed where female labour supply is determined as a collective household decision and depends on male and female wages and intra-household power distribution. On the other hand, the effect of power distribution on female labour supply depends on social norms.

Findings

Comparative static analysis shows that a tariff cut may reduce female labour force participation and widen gender earning inequality if (i) the agricultural sector is more male labour-intensive than the informal sector, and the marginal utility of the woman from household work is higher than that of the man or (ii) the agricultural sector is more female labour-intensive than the informal sector, and the marginal utility of the woman’s household work is higher to the man than the woman. Policies to raise the empowerment of women might lead to favourable labour market outcomes for women if the marginal utility of the woman’s household work is higher to the man than the woman irrespective of the factor intensity condition.

Research limitations/implications

The results signify that the effect of trade liberalization hinges on both factor intensity conditions and the relative work preferences of women vis-à-vis men, which in turn is shaped by social norms.

Originality/value

The paper contributes to the scant theoretical literature on labour market consequences of trade liberalization by considering the gender equality implications of trade liberalization from a supply side perspective. The results of the model are used to explain the recent gendered labour market consequences in India in the aftermath of trade liberalization.
The upper echelon effect on restaurant franchising: the moderating role of internationalization
Authors: Lee Won Seok , Choi Choongbeom , Moon Joonho
Published: February 2018

Purpose

This study aims to investigate how upper echelon theory accounts for franchising by selecting the top management team to proxy for the upper echelon and using age, tenure, education, equity ownership and stock options as its main attributes.

Design/methodology/approach

The sample was drawn from the Execucomp and Compustat databases and from other publicly accessible resources (e.g. LinkedIn and Business Week, in addition to Annual 10-K reports). A total of 29 restaurant companies were used for data collection, which covered the period of 2000-2013. A panel feasible generalized least squares (FGLS) regression was used to analyze the data.

Findings

The study found a significant moderating effect of the degree of internationalization on the relation between the attributes of the upper echelon (e.g. tenure, education and share ownership) and franchising decisions.

Research limitations/implications

The results verified that top managers in the restaurant industry with more tenure and share ownership become more risk averse when they operate under riskier conditions, whereas highly educated restaurant top management teams tend to take more risks in strategic decision-making.

Originality/value

This study expanded internationalization research to upper echelon theory and into the arena of franchising.
Sympathy and loyalty intention after visitor harassment
Authors: Nicely Annmarie , Armadita Filza
Published: February 2018

Purpose

The purpose of this study was to, first, determine the demographic predictors of the extent a visitor would feel sympathetic after a visitor harassment (VH) episode and, second, to ascertain whether there were any significant connections between a visitor feeling sympathetic after such an episode and his or her loyalty intentions toward the destination.

Design/methodology/approach

A survey research was conducted. Snowballing was used for the online survey and accidental sampling for the paper survey. The data were analyzed using ordinal logistic regression analyses. A total of 634 surveys were analyzed.

Findings

The following were found. First, sympathy was not a common emotion visitors experienced after being harassed by a trader at a tourist destination. Second, the demographic factors age, gender, income and educational levels were not significant predictors of the extent to which visitors would be sympathetic after a VH episode. Sympathy was a significant predictor of visitors’ intention to recommend the destination and support the traders in the future but not of visitors’ intention to return to the destination.

Research limitations/implications

The study was exploratory, and hence, the findings were preliminary.

Practical implications

The findings could lead to “new” local responses to the problem of VH at tourist destinations.

Originality/Value

The study was the first known to look at visitor sympathy after a VH episode.