bluuebunny/crossref_metadata_2025 huggingface dataset:
Extensive transcriptional and chromatin changes underlie astrocyte maturationin vivoand in culture
Authors: Lattke Michael , Goldstone Robert , Guillemot Francois
Published: April 2020

Astrocytes have diverse functions in brain homeostasis. Many of these functions are acquired during late stages of differentiation when astrocytes become fully mature. The mechanisms underlying astrocyte maturation are not well understood. Here we identified extensive transcriptional changes that occur during astrocyte maturation and are accompanied by chromatin remodelling at enhancer elements. Investigating astrocyte maturation in a cell culture model revealed thatin vitro-differentiated astrocytes lacked expression of many mature astrocyte-specific genes, including genes for the transcription factors Rorb, Dbx2, Lhx2 and Fezf2. Forced expression of these factorsin vitroinduced distinct sets of mature astrocytes-specific transcripts. Culturing astrocytes with FGF2 in a three-dimensional gel induced expression ofRorb,Dbx2andLhx2and improved their maturity based on transcriptional and chromatin profiles. Therefore extrinsic signals orchestrate the expression of multiple intrinsic regulators, which in turn induce in a modular manner the transcriptional and chromatin changes underlying astrocyte maturation.
Predicting the potency of anti-Alzheimer drug combinations using machine learning
Authors: Anastasio Thomas J
Published: April 2020

BACKGROUND

Clinical trials of single drugs for the treatment of Alzheimer Disease (AD) have been notoriously unsuccessful. Combinations of repurposed drugs could provide effective treatments for AD. The challenge is to identify potentially potent combinations.

OBJECTIVE

To use machine learning (ML) to extract the knowledge from two leading AD databases, and then use the machine to predict which combinations of the drugs in common between the two databases would be the most effective as treatments for AD.

METHODS

Three-layered neural networks (NNs) having compound, gated units in their internal layer were trained using ML to predict the cognitive scores of participants in either database, given the other data fields including age, demographic variables, comorbidities, and drugs taken.

RESULTS

The predictions from the separately trained NNs were strongly correlated. The best drug combinations, jointed determined from both sets of predictions, were high in NSAID, anticoagulant, lipid-lowering, and antihypertensive drugs, and female hormones.

CONCLUSION

The results suggest that AD, as a multifactorial disorder, could be effectively treated using a combination of repurposed drugs.
Aspects of the ecology ofBartramia hallerianaandCrossocalyx hellerianusin oceanic deciduous woodland
Authors: Callaghan Des A. , Bevan Jamie
Published: April 2020

Introduction

This study investigates the ecology of two boreal-montane bryophytes, the saxicolous mossBartramia hallerianaand the epixylic liverwortCrossocalyx hellerianus, at the edge of their ranges, in oceanic deciduous woodland.

Methods

The study site comprises two adjoining woodlands, Allt Penyrhiw-iar (canopy trees ca. 100 yr old) and Allt Rhyd Groes (ca. 200 yr), Carmarthenshire, UK. The distribution and abundance ofB. hallerianaandC. hellerianuswas surveyed, relevés sampled to record habitat and community composition, and sporophyte frequency and stage of development measured. Light climate ofB. hallerianawas investigated via hemispherical photography, and abundance of large rotten logs used as a measure of habitat quality forC. hellerianus.

Results and discussion

Four subpopulations ofB. hallerianaoccur, comprising 21 individual-equivalents (occupied 1 m grid cells), all on mildly base-rich mudstone of north-facing rockfaces, with very little direct solar radiation and a diverse assemblage of bryophytes. Sporophyte are scarce. A total of 143 individual-equivalents (occupied logs or trees) ofC. hellerianuswas recorded, an exceptional population in Wales. Most of the population is within Allt Rhyd Groes, where large rotten logs are much more abundant due to greater woodland age. The liverwort mainly occupied the sides of decorticated rotten logs, amongst a sparse community composed mainly of other small liverworts andCladonialichens. Neither sporophytes nor perianths were found. Further research could usefully focus on the description and measurement of favourable habitat for each species and associated physiological tolerances.
On the fitness of informative cues in complex environments
Authors: Mafessoni Fabrizio , Lachmann Michael , Gokhale Chaitanya S.
Published: April 2020

To be able to deal with uncertainty is of primary importance to most living organisms. When cues provide information about the state of the environment, organisms can use them to respond flexibly. Life forms have evolved complex adaptations and sensory mechanisms to use these environmental cues and extract valuable information about the environment. Previous work has shown a theoretical limit to the amount of fitness benefit possible to be extracted from the cues. We show that the previously used information theoretical approaches can be generalised to scenarios involving any potential relationship between the number of possible phenotypes and environmental states. Such cases are relevant when physiological constraints or complex ecological scenarios lead to the number of environmental states exceeding potential phenotypes. We illustrate cases in which these scenarios can emerge: along environmental gradients, such as geographical transects or complex environments, where organisms adopt different bet-hedging strategies, switching stochastically between phenotypes or developing intermediate ones. In conclusion, we develop an information-theoretic extensible approach for investigating and quantifying fitness in ecological studies.
A central amygdala-globus pallidus circuit conveys unconditioned stimulus information and controls fear learning
Authors: Giovanniello Jacqueline , Yu Kai , Furlan Alessandro , Nachtrab Gregory Thomas , Sharma Radhashree , Chen Xiaoke , Li Bo
Published: April 2020

The central amygdala (CeA) is critically involved in a range of adaptive behaviors. In particular, the somatostatin-expressing (Sst+) neurons in the CeA are essential for classic fear conditioning. These neurons send long-range projections to several extra-amygdala targets, but the functions of these projections remain elusive. Here, we found in mice that a subset of Sst+CeA neurons send projections to the globus pallidus external segment (GPe), and constitute essentially the entire GPe-projecting CeA population. Notably, chronic inhibition of GPe-projecting CeA neurons completely blocks auditory fear conditioning. These neurons are selectively excited by the unconditioned stimulus (US) during fear conditioning, and transient inactivation or activation of these neurons during US presentation impairs or promotes, respectively, fear learning. Our results suggest that a major function of Sst+CeA neurons is to represent and convey US information through the CeA-GPe circuit, thereby instructing learning in fear conditioning.
Diversity begets diversity in human cultures and mammal species
Authors: Hamilton Marcus J. , Walker Robert S. , Kempes Chris
Published: April 2020

A key feature of the distribution of life on Earth is the positive correlation between environmental productivity and biodiversity. This correlation also characterizes the distribution of human cultural diversity, which is highest near the equator and decreases exponentially toward the poles. Moreover, it is now understood that the tropics house more biodiversity than would be expected from energy availability alone suggesting “diversity begets diversity”. Here we show the same is also true for human cultural diversity. This convergence is particularly striking because while the dynamics of biological and cultural evolution may be similar in principle the mechanisms and time scales involved are very different. However, a common currency underlying all forms of diversity is ecological kinetics; the temperature-dependent fluxes of energy and biotic interactions that sustain life at all levels of biological and social organization. Using macroecological theory and the analysis of global databases we show both mammal diversity and cultural diversity scale superlinearly with environmental productivity at rates predicted by the ecological kinetics of environmental productivity. Diversity begets diversity in human cultures and mammal species because the kinetics of energy availability and biotic interactions result in superlinear scaling with environmental productivity.
Dragonfly Inspired Smart Soft Robot
Authors: Kumar Vardhman , Ko Ung Hyun , Zhou Yilong , Hoque Jiaul , Arya Gaurav , Varghese Shyni
Published: April 2020

Recent advancements in soft robotics have led to the development of compliant robots that can exhibit complex motions driven by living cells(1,2), chemical reactions(3), or electronics(4). Further innovations are however needed to create the next generation of soft robots that can carry out advanced functions beyond locomotion. Here we describeDraBot—a dragonfly-inspired, entirely soft, multifunctional robot that combines long-term locomotion over water surface with sensing, responding, and adaptation capabilities. By integrating soft actuators, stimuli-responsive materials, and microarchitectural features, we created a circuitry of pneumatic and microfluidic logic that enabled the robot to undergo user- and environment-controlled (pH) locomotion, including navigating hazardous (acidic) conditions. DraBot was also engineered to sense additional environmental perturbations (temperature) and detect and clean up chemicals (oil). The design, fabrication, and integration strategies demonstrated here pave a way for developing futuristic soft robots that can acclimatize and adapt to harsh conditions while carrying out complex tasks such as exploration, environmental remediation, and health care in complex environments.
Super-selective reconstruction of causal and direct connectivity with application toin-vitroiPSC neuronal networks
Authors: Puppo Francesca , Pré Deborah , Bang Anne , Silva Gabriel A.
Published: April 2020

Despite advancements in the development of cell-basedin-vitroneuronal network models, the lack of appropriate computational tools limits their analyses. Methods aimed at deciphering the effective connections between neurons from extracellular spike recordings would increase utility ofin-vitrolocal neural circuits, especially for studies of human neural development and disease based on induced pluripotent stem cells (hiPSC). Current techniques allow statistical inference of functional couplings in the network but are fundamentally unable to correctly identify indirect and apparent connections between neurons, generating redundant maps with limited ability to model the causal dynamics of the network. In this paper, we describe a novel mathematically rigorous, model-free method to map effective - direct and causal - connectivity of neuronal networks from multi-electrode array data. The inference algorithm uses a combination of statistical and deterministic indicators which, first, enables identification of all existing functional links in the network and then, reconstructs the directed and causal connection diagram via a super-selective rule enabling highly accurate classification of direct, indirect and apparent links. Our method can be generally applied to the functional characterization of anyin-vitroneuronal networks. Here, we show that, given its accuracy, it can offer important insights into the functional development ofin-vitroiPSC-derived neuronal cultures.
How spiders make their eyes: Systemic paralogy and function of retinal determination network homologs in arachnids
Authors: Gainett Guilherme , Ballesteros Jesús A. , Kanzler Charlotte R. , Zehms Jakob T. , Zern John M. , Aharon Shlomi , Gavish-Regev Efrat , Sharma Prashant P.
Published: April 2020

Arachnids are important components of cave ecosystems and display many examples of troglomorphisms, such as blindness, depigmentation, and elongate appendages. Little is known about how the eyes of arachnids are specified genetically, let alone the mechanisms for eye reduction and loss in troglomorphic arachnids. Additionally, paralogy of Retinal Determination Gene Network (RDGN) homologs in spiders has convoluted functional inferences extrapolated from single-copy homologs in pancrustacean models. Here, we investigated a sister species pair of Israeli cave whip spiders (Arachnopulmonata, Amblypygi,Charinus) of which one species has reduced eyes. We generated the first embryonic transcriptomes for Amblypygi, and discovered that several RDGN homologs exhibit duplications. We show that paralogy of RDGN homologs is systemic across arachnopulmonates (arachnid orders that bear book lungs), rather than being a spider-specific phenomenon. A differential gene expression (DGE) analysis comparing the expression of RDGN genes in field-collected embryos of both species identified candidate RDGN genes involved in the formation and reduction of eyes in whip spiders. To ground bioinformatic inference of expression patterns with functional experiments, we interrogated the function of three candidate RDGN genes identified from DGE in a spider, using RNAi in the spiderParasteatoda tepidariorum.We provide functional evidence that one of these paralogs,sine oculis/Six1 A(soA), is necessary for the development of all arachnid eye types. Our results support the conservation of at least one RDGN component across Arthropoda and establish a framework for investigating the role of gene duplications in arachnid eye diversity.
Predicting sites of epitranscriptome modifications using unsupervised representation learning based on generative adversarial networks
Authors: Salekin Sirajul , Mostavi Milad , Chiu Yu-Chiao , Chen Yidong , Zhang Jianqiu (Michelle) , Huang Yufei
Published: April 2020

Epitranscriptome is an exciting area that studies different types of modifications in transcripts and the prediction of such modification sites from the transcript sequence is of significant interest. However, the scarcity of positive sites for most modifications imposes critical challenges for training robust algorithms. To circumvent this problem, we propose MR-GAN, a generative adversarial network (GAN) based model, which is trained in an unsupervised fashion on the entire pre-mRNA sequences to learn a low dimensional embedding of transcriptomic sequences. MR-GAN was then applied to extract embeddings of the sequences in a training dataset we created for eight epitranscriptome modifications, including m6A, m1A, m1G, m2G, m5C, m5U, 2′-O-Me, Pseudouridine (Ψ) and Dihydrouridine (D), of which the positive samples are very limited. Prediction models were trained based on the embeddings extracted by MR-GAN. We compared the prediction performance with the one-hot encoding of the training sequences and SRAMP, a state-of-the-art m6A site prediction algorithm and demonstrated that the learned embeddings outperform one-hot encoding by a significant margin for up to 15% improvement. Using MR-GAN, we also investigated the sequence motifs for each modification type and uncovered known motifs as well as new motifs not possible with sequences directly. The results demonstrated that transcriptome features extracted using unsupervised learning could lead to high precision for predicting multiple types of epitranscriptome modifications, even when the data size is small and extremely imbalanced.
Escherichia colihas a Unique Transcriptional Program in Long-Term Stationary Phase
Authors: Kram Karin E. , Henderson Autumn , Finkel Steven E.
Published: April 2020

Microbes live in complex and consistently changing environments, but it is difficult to replicate this in the laboratory.Escherichia colihas been used as a model organism in experimental evolution studies for years; specifically, we and others have used it to study evolution in complex environments by incubating the cells into long-term stationary phase (LTSP) in rich media. In LTSP, cells experience a variety of stresses and changing conditions. While we have hypothesized that this experimental system is more similar to natural environments than some other lab conditions, we do not yet know how cells respond to this environment biochemically or physiologically. In this study, we begin to unravel the cells’ responses to this environment by characterizing the transcriptome of cells during LTSP. We found that cells in LTSP have a unique transcriptional program, and that several genes are uniquely upregulated or downregulated in this phase. Further, we identified two genes,cspBandcspI, which are most highly expressed in LTSP, even though these genes are primarily known to respond to cold-shock. When competed with wild-type cells, these genes are also important for survival during LTSP. These data allow us to compare biochemical responses to multiple environments and identify useful model systems, identify gene products that may play a role in survival in this complex environment, and identify novel functions of proteins.

Importance

Experimental evolution studies have elucidated evolutionary processes, but usually in chemically well-defined and/or constant environments. Using complex environments is important to begin to understand how evolution may occur in natural environments, such as soils or within a host. However, characterizing the stresses cells experience in these complex environments can be challenging. One way to approach this is by determining how cells biochemically acclimate to heterogenous environments. In this study we begin to characterize physiological changes by analyzing the transcriptome of cells in a dynamic complex environment. By characterizing the transcriptional profile of cells in long-term stationary phase, a heterogenous and stressful environment, we can begin to understand how cells physiologically and biochemically react to the laboratory environment, and how this compares to more natural conditions.
ARBitR: An overlap-aware genome assembly scaffolder for linked reads
Authors: Hiltunen Markus , Ryberg Martin , Johannesson Hanna
Published: April 2020

10X Genomics Chromium linked reads contain information that can be used to link sequences together into scaffolds in draft genome assemblies. Existing software for this purpose perform the scaffolding by joining sequences together with a gap between them, not considering potential contig overlaps. Such overlaps can be particularly prominent in genome drafts assembled from long-read sequencing data where an overlap-layout-consensus (OLC) algorithm has been used. Ignoring overlapping contig ends may result in genes and other features being incomplete or fragmented in the resulting scaffolds. We developed the application ARBitR to generate scaffolds from genome drafts using 10X Chromium data, with a focus on minimizing the number of gaps in resulting scaffolds by incorporating an OLC step to resolve junctions between linked contigs. We tested the performance of ARBitR on three published and simulated datasets and compared to the previously published tools ARCS and ARKS. The results revealed that ARBitR performed similarly considering contiguity statistics, and the advantage of the overlapping step was revealed by fewer long and short variants in ARBitR produced scaffolds, in addition to a higher proportion of completely assembled LTR retrotransposons. We expect ARBitR to have broad applicability in genome assembly projects that utilize 10X Chromium linked reads.

Availability and implementation

ARBitR is written and implemented in Python3 for Unix-like operative systems. All source code is available athttps://github.com/markhilt/ARBitRunder the GNU General Public License v3.

Contact

markus.hiltunen@ebc.uu.se

Supplementary information

available online
Spectrin-based Membrane Mechanics Is Asymmetric and Remodels during Neural Development
Authors: Jia Ru , Chai Yongping , Xie Chao , Liu Gai , Zhu Zhiwen , Huang Kaiyao , Li Wei , Ou Guangshuo
Published: April 2020

Perturbation of spectrin-based membrane mechanics causes hereditary elliptocytosis and spinocerebellar ataxia, but the underlying cellular basis of pathogenesis remains unclear. Here, we introduced the conserved disease-associated spectrin mutations into the C. elegans genome and studied the contribution of spectrin to neuronal migration and dendrite formation in developing larvae. The loss of spectrin generates an ectopic actin polymerization outside of the existing front and secondary membrane protrusions, leading to defective neuronal positioning and dendrite morphology in adult animals. Spectrin accumulates in the lateral and the rear of migrating neuroblasts and redistributes from the soma into the newly formed dendrites, indicating that the spectrin-based membrane skeleton is asymmetric and remodels to regulate actin assembly and cell shape during development. We affinity-purified spectrin from C. elegans and showed that its binding partner ankyrin functions with spectrin. Asymmetry and remodeling of membrane skeleton may enable spatiotemporal modulation of membrane mechanics for distinct developmental events.

Significance Statement

The biomechanical regulation of neural development is largely unknown. The spectrin-based membrane skeleton is essential for the structural integrity of the plasma membrane. This study addresses the function and behavior of spectrin in neuroblast migration and dendrite formation. The loss of spectrin generates an ectopic actin polymerization outside of the existing front, leading to defective neuronal positioning and dendrite morphology. Spectrin is absent from the leading edge but accumulates in the posterior of migrating neuroblasts and redistributes from the soma into the nascent dendrites, indicating that the membrane skeleton is asymmetric and remodels. Asymmetry and remodeling of the membrane skeleton may enable spatiotemporal modulation of membrane mechanics for distinct developmental events.
Predicting Antimicrobial Resistance Using Conserved Genes
Authors: Nguyen Marcus , Olson Robert , Shukla Maulik , VanOeffelen Margo , Davis James J.
Published: April 2020

A growing number of studies have shown that machine learning algorithms can be used to accurately predict antimicrobial resistance (AMR) phenotypes from bacterial sequence data. In these studies, models are typically trained using input features derived from comprehensive sets of known AMR genes or whole genome sequences. However, it can be difficult to determine whether genomes and their corresponding sets of AMR genes are complete when sequencing contaminated or metagenomic samples. In this study, we explore the possibility of using incomplete genome sequence data to predict AMR phenotypes. Machine learning models were built from randomly-selected sets of core genes that are held in common among the members of a species, and the AMR-conferring genes were removed based on their protein annotations. ForKlebsiella pneumoniae,Mycobacterium tuberculosis,Salmonella enterica, andStaphylococcus aureus, we report that it is possible to classify susceptible and resistant phenotypes with average F1 scores ranging from 0.80-0.89 with as few as 100 conserved non-AMR genes, with very major error rates ranging from 0.11-0.23 and major error rates ranging from 0.10-0.20. Models built from core genes have predictive power in the cases where the primary AMR mechanism results from SNPs or horizontal gene transfer. By randomly sampling non-overlapping sets of core genes for use in these models, we show that F1 scores and error rates are stable and have little variance between replicates. Potential biases from strain-specific SNPs, phylogenetic sampling, and imbalances in the phylogenetic distribution of susceptible and resistant strains do not appear to have an impact on this result. Although these small core gene models have lower accuracies and higher error rates than models built from the corresponding assembled genomes, the results suggest that sufficient variation exists in the core non-AMR genes of a species for predicting AMR phenotypes. Overall this study suggests that building models from conserved genes may be a potentially useful strategy for predicting AMR phenotypes when genomes are incomplete.
Gut expressed vitellogenin is hijacked by a virus to facilitate its spread
Authors: He Ya-Zhou , Wang Yu-Meng , Yin Tian-Yan , Liu Shu-Sheng , Wang Xiao-Wei
Published: April 2020

Insect vitellogenin (Vg) has been considered to be synthesized in the female fat body, secreted into hemolymph, and taken up by developing oocytes to serve as nutrition for embryo development. However, the expression and function of Vg in other tissues are largely unknown. Here, we show that Vg is expressed in the whitefly midgut epithelial cells and secreted into gut lumen where it binds to the microvillar membrane. Furthermore, we find that the midgut expressed Vg is hijacked byTomato yellow leaf curl virusto facilitate the movement of virus crossing the midgut wall. Silencing of Vg or immune-blocking the interaction between viral coat protein and midgut Vg inhibited virus movement across the midgut wall and decreased virus transmission. Our findings show possession of functional Vg in the midgut of an insect, and reveal a novel mechanism involved in the movement of virus crossing the midgut barrier of vector insect.
Novel structural components generate distinct type VI secretion system anchoring modes
Authors: Bernal Patricia , Furniss R. Christopher D. , Fecht Selina , Leung Rhoda C.Y. , Spiga Livia , Mavridou Despoina A.I. , Filloux Alain
Published: April 2020

The type VI secretion system (T6SS) is a phage-derived contractile nanomachine primarily involved in interbacterial competition. Its pivotal component, TssA, is indispensable for the assembly of the T6SS sheath structure, the contraction of which propels a payload of effector proteins into neighboring cells. Despite their key function, TssA proteins exhibit unexpected diversity and exist in two major forms, a short (TssAS) and a long (TssAL) TssA. Whilst TssALproteins interact with a partner, called TagA, to anchor the distal end of the extended sheath, the mechanism for the stabilization of TssAS-containing T6SSs remains unknown. Here we discover a novel class of structural components that interact with short TssA proteins and contribute to T6SS assembly by stabilizing the polymerizing sheath from the baseplate. We demonstrate that the presence of these components is important for full sheath extension and optimal firing. Moreover, we show that the pairing of each form of TssA with a different class of sheath stabilization proteins results in T6SS apparatuses that either reside in the cell for a while or fire immediately after sheath extension, thus giving rise to different aggression behaviors. We propose that this functional diversity could contribute to the specialization of the T6SS to suit bacterial lifestyles in diverse environmental niches.
Organisation and management of grey literature in select social science libraries
Authors: Bhatt R.K. , Singh Monika , Rana Jyoti , Kumar Jatin
Published: April 2020

Purpose

This paper aims to study the organisation and management of grey literature (GL) to select social science libraries. Further, the study is an attempt to make known the types of GL; extent of demand and the frequency of use of GL; GL collection in other languages; workshops or training programmes or seminars for GL; bibliographic control for GL, etc., in select social science libraries.

Design/methodology/approach

A survey with the help of a questionnaire followed by interviews was conducted among the social science libraries understudy to explore the issues and challenges involved in organizing and managing GL.

Findings

The study finds that 83.3% of libraries have a separate wing for the management of GL and the majority of the GL acquired by the library are accessed through compact disc and are present in digital form access via online public access catalog.

Originality/value

The paper explores the organisation and management of GL by social science libraries, which is a unique study on its own as the management of GL is not much popular here in India. The study paves the path for more issues to be explored in the area i.e. GL.
Influence of the chamber inclination angle and heat-generating element location on thermal convection of power-law medium in a chamber
Authors: Loenko Darya , Shenoy Aroon , Sheremet Mikhail
Published: April 2020

Purpose

This paper aims to study the mathematical modeling of passive cooling systems for electronic devices. Improving heat transfer is facilitated by the correct choice of the working fluid and the geometric configuration of the engineering cavity; therefore, this work is devoted to the analysis of the influence of the position of the heat-generating element and the tilted angle of the electronic cabinet on the thermal convection of a non-Newtonian fluid.

Design/methodology/approach

The area of interest is a square cavity with two cold vertical walls, while the horizontal boundaries are adiabatic. An element of constant volumetric heat generation is placed on the lower wall of the chamber. The problem is described by Navier–Stokes partial differential equations using dimensionless stream function and vorticity. The numerical solution is based on the developed computational code using the finite difference technique and a uniform rectangular grid.

Findings

The key conclusions of this work are the results of a detailed analysis of streamlines and isotherms, the average Nusselt number and profiles of the average heater temperature. It was found that more intensive cooling of the heat-generating element occurs when the cavity is filled with a pseudoplastic fluid (n < 1) and not inclined (α = 0). The Rayleigh number of Ra = 105and the thermal conductivity ratio ofk = 100 are characterized by the most positive effect.

Originality/value

The originality of the research lies in both the study of thermal convection in a square chamber filled with power-law fluid under the influence of a volumetric heat production element and the analysis of the influence of geometric and thermophysical parameters characterizing the considered process.
Magneto-hydrodynamics of a solid-liquid two-phase fluid in rotating channel due to peristaltic wavy movement
Authors: Haider Sajjad , Ijaz Nouman , Zeeshan A. , Li Yun-Zhang
Published: April 2020

Purpose

Numerous researchers have probed the peristaltic flows because of their immense usage in industrial engineering, biomedical engineering and biological sciences. However, the investigation of peristaltic flow in two-phase fluid of a rotating frame in the presence of a magnetic field has not been yet discussed. Therefore, to fulfill this gap in the existing literature, this paper will explicate the peristaltic flow of two-phase fluid across a rotating channel with the effect of wall properties in the presence of a magnetic field. The purpose of this study is to investigate the two-phase velocity distribution and rotation parameter when magneto-hydrodynamics is applied.

Design/methodology/approach

The constituent equations are solved under the condition of low Reynolds number and long wavelength. The exact method is used to attain the subsequent equations and a comprehensive graphical study for fluid phase, particulate phase velocity and flow rates are furnished. The impacts of pertinent parameters, magnetic field and rotation are discussed in detail.

Findings

It is witnessed that the velocity profile of particulate phase gets higher values for the same parameters as compared to the fluid phase velocity. Moreover, the axial velocity increases with different values of particle volume fraction, but in case of magnetic field and rotation parameter, it shows the opposite behavior.

Practical implications

The outcomes of study have viable industrial implementations in systems comprising solid-liquid based flows of fluids involving peristaltic movement.

Originality/value

The investigation of peristaltic flow in two-phase fluid of a rotating frame in the presence of a magnetic field has not been yet discussed. Therefore, to fulfill this gap, the present study will explicate the peristaltic flow of two-phase fluid across a rotating channel with the effect of wall properties in the presence of magnetic field.
Are Islamic mutual funds exposed to lower risk compared to their conventional counterparts?
Authors: Naveed Farrukh , Khawaja Idrees , Maroof Lubna
Published: April 2020

Purpose

This study aims to comparatively analyze the systematic, idiosyncratic and downside risk exposure of both Islamic and conventional funds in Pakistan to see which of the funds has higher risk exposure.

Design/methodology/approach

The study analyzes different types of risks involved in both Islamic and conventional funds for the period from 2009 to 2016 by using different risk measures. For systematic and idiosyncratic risk single factor CAPM and multifactor models such as Fama French three factors model and Carhart four factors model are used. For downside risk analysis different measures such as downside beta, relative beta, value at risk and expected short fall are used.

Findings

The study finds that Islamic funds have lower risk exposure (including total, systematic, idiosyncratic and downside risk) compared with their conventional counterparts in most of the sample years, and hence, making them appear more attractive for investment especially for Sharīʿah-compliant investors preferring low risk preferences.

Practical implications

As this study shows, Islamic mutual funds exhibit lower risk exposure than their conventional counterparts so investors with lower risk preferences can invest in these kinds of funds. In this way, this research provides the input to the individual investors (especially Sharīʿah-compliant investors who want to avoid interest based investment) to help them with their investment decisions as they can make a more diversified portfolio by considering Islamic funds as a mean for reducing the risk exposure.

Originality/value

To the best of the author’s knowledge, this study is the first attempt at world level in looking at the comparative risk analysis of various types of the risks as follows: systematic, idiosyncratic and downside risk, for both Islamic and conventional funds, and thus, provides significant contribution in the literature of mutual funds.
Audit quality, political connections and information asymmetry: evidence from banks in gulf co-operation council countries
Authors: Tessema Abiot
Published: April 2020

Purpose

The purpose of this paper is to investigate the impact of audit quality on information asymmetry for a sample of leading listed local banks in the Gulf Cooperation Council (GCC). In addition, the paper examines whether a firm's political connections moderate the association between audit quality and information asymmetry.

Design/methodology/approach

The author employs country fixed effects to examine the impact of audit quality on information asymmetry. The paper uses a sample of 49 leading listed local banks across the GCC and 236 bank-year observations, over the period of 2012–2016.

Findings

Using trading volume, trade value and stock return volatility as proxies for information asymmetry and audit quality through auditors' opinion and audit size, the paper documents that audit quality plays an important role in improving the quality of financial information reporting by providing greater independent assurance of the credibility of financial reports. The paper also documents that a firm's political connections have no effect on the association between audit quality and information asymmetry, indicating that the beneficial effects of audit quality are no greater for politically connected firms than for similar but politically unconnected firms.

Practical implications

The findings of the study help policymakers, standard-setters and regulators to understand the potential adverse effect of political connections on the role of audit quality on information asymmetry. The study also provides important insights for audit regulators to better identify and understand the benefits of audit quality and to take policy matters that influence audit quality seriously.

Originality/value

The study increases our understanding of the impact of audit quality on the level of information asymmetry in different economic, legal and political institutions, regulatory and litigation incentives and social contexts compared to that of research conducted using data collected from developed and other emerging countries. This will help to widen our knowledge on the role of audit quality on information asymmetry across the globe.
The effects of materialism on consumer evaluation of sustainable synthetic (lab-grown) products
Authors: Keech Jessica , Morrin Maureen , Podoshen Jeffrey Steven
Published: April 2020

Purpose

The increasing desire of consumers for socially responsible luxury products combined with fluctuating supplies in consumer markets are leading various industries to seek alternative sources to be able to meet the needs of its customers. One possible solution that may meet the demands of the future is lab-grown products. Because these products confer multiple benefits, this study aims to investigate the most effective ways to appeal to consumers by aligning the benefits of the products with their values as marketers seek to find effective promotion for these items.

Design/methodology/approach

We examine the effectiveness of an ethical positioning strategy for two types of luxury lab-grown (synthetic) products among high versus low materialism consumers in three experiments.

Findings

Findings suggest that a positioning strategy stressing product ethicality is more effective for low materialism consumers, whereas the strategy is less effective, and may even backfire, for high materialism consumers. The impact on social status consumers perceive from a lab-grown product explains why this effect occurs among low materialism consumers. Therefore, marketers should take caution and use specific appeals for different segments based on values such as consumers’ materialism levels.

Originality/value

If lab-grown products represent the wave of the future, it is important to understand how consumers will respond to this emerging technology and how promotion strategies may enhance their evaluation.
The media as an investigative resource: reflections from English cold-case units
Authors: Bennett Kirsty
Published: April 2020

Purpose

The use of the media in live cases has been explored in terms of its use and value to an investigation. However, it is unclear as to whether engaging with the media in cold-case investigations results in a positive or negative reception, and what impact this can have on a case’s possibility for progression. Because of the passage of time and a lack of, or a failed, prosecution means that the approach to media use needs to be different. The purpose of this paper is to explore how the media could be used as an investigative resource for cold cases.

Design/methodology/approach

This study is a result of a 7-month observation period with a 2-force collaborative cold-case team in England, and supplemented with interviews with 12 experienced cold-case detectives. Using inductive thematic analysis, the themes identified allow an exploration of detectives’ use of the media and the effect that this has on progressing cases. Further, there is discussion as to whether the media’s involvement is positive or negative.

Findings

The overarching theme is that when using the media, cold-case detectives are met with a positive reception and interest. The media can be used to obtain information, particularly in cases with minimal information, and it is important to use murder-anniversaries to obtain help from the public. However, this needs to be a carefully managed strategy as the media coverage can be negative, including inaccurate or inappropriate reporting which can be of detriment to the investigation.

Originality/value

To the best of the author’s knowledge, this is the first paper to explore how cold-case detectives have used the media to progress cases, and the findings demonstrate that when the public are encouraged to come forward with information, there is a better chance of case progression. Further research is required to explore how all cold cases can receive appropriate coverage.
A decision model for selecting a safety data sheet management system using fuzzy TOPSIS
Authors: Ahmed Abdulaziz , Naji Ahmed , Tseng Ming-Lang
Published: April 2020

Purpose

Safety data sheets are documents developed by chemical manufacturers to identify and label hazardous materials. The occupational safety and health administration regulations state that employers must make safety data sheets available for employees. When firms use hundreds of chemicals, tracking their safety data sheets becomes difficult. Safety Data Sheet Management Systems are developed to track safety data sheets. This paper aims to propose a multi-attribute decision-making framework for selecting a Safety Data Sheet Management System.

Design/methodology/approach

A total of 12 attributes are proposed based on a real-life project conducted at a firm in New York and the software selection models existed in the literature. Fuzzy technique for order of preference by similarity to ideal solution is used to assess the proposed attributes and alternatives. A case study and sensitivity analysis are conducted to show the robustness of the proposed model. Fuzzy analytical hierarchy process is used for validation.

Findings

Safety Data Sheet Management System is important for firms to track and manage safety data sheets. The proposed framework is practical and easy to implement.

Practical implications

The proposed decision model is useful for firms to select a proper Safety Data Sheet Management System. The system developers can use the model to update their systems.

Originality/value

This paper develops a new multi-attribute decision-making model for selecting a Safety Data Sheet Management System. To the best of the authors’ knowledge, no previous study has developed such a model.
Conceptualizing employee strengths at work and scale development
Authors: Bhatnagar Vikas Rai
Published: April 2020

Purpose

There is a compelling need for developing constructs in management science for higher relevance rather than adapting constructs developed in other domains and applying them in organizations. An inquiry in the relevance of the construct of strength developed in personality psychology and applied to organizations is compelling, as deploying strengths leads to humanizing organizations. With growing disengagement of employees at work, this study makes a significant contribution by conceptualizing strengths in the context of organizations and carrying out two studies on independent samples for developing a psychometrically validated 14-item scale for measuring it.

Design/methodology/approach

The study has two phases. The first phase is conceptual in nature where the authors deploy the social systems theory and use recent empirical research evidence in conceptualizing the construct of employee strengths at work (ESAW). In the second phase, the author carry out two studies on independent samples for ascertaining the factor structure by carrying out EFA and then confirming it by doing a confirmatory factor analysis.

Findings

The construct of ESAW, relevant for management science, has five factors: potential deployment, person-jot fit, managerial sensitivity, prompt assimilation and joy. The psychometrically validated scale for measuring ESAW developed in this study has 14 items. Because the construct incorporates key contextual factors, it is more relevant to organizational science and contributes to humanizing organizations.

Originality/value

This study evolves the construct of ESAW from a predominantly trait-based approach to a conceptualization that accounts for the contextual factors, essential for enabling strengths of employees to manifest. The study contributes to advancing literature that holds promise for humanizing organizations – a pressing need because of the growing instances of employee disengagement. The author develop a 14-item psychometrically validated scale for measuring ESAW that the practitioners can use in first assessing current levels of employee strengths’ deployment and thereafter intervening for increasing the deployment of their strengths for enabling higher well-being and superior performance.
The FloR master regulator controls flotation, virulence and antibiotic production in Serratia sp. ATCC 39006
Authors: Quintero‐Yanes Alex , Lee Chin Mei , Monson Rita , Salmond George
Published: April 2020

Serratia sp. ATCC 39006 produces intracellular gas vesicles to enable upward flotation in water columns. It also uses flagellar rotation to swim through liquid and swarm across semi‐solid surfaces. Flotation and motility can be co‐regulated with production of a β‐lactam antibiotic (carbapenem carboxylate) and a linear tripyrrole red antibiotic, prodigiosin. Production of gas vesicles, carbapenem and prodigiosin antibiotics, and motility are controlled by master transcriptional and post‐transcriptional regulators, including the SmaI/SmaR‐based quorum sensing system and the mRNA binding protein, RsmA. Recently, the ribose operon repressor, RbsR, was also defined as a pleiotropic regulator of flotation and virulence factor elaboration in this strain. Here, we report the discovery of a new global regulator (FloR; a DeoR family transcription factor) that modulates flotation through control of gas vesicle morphogenesis. The floR mutation is highly pleiotropic, down‐regulating production of gas vesicles, carbapenem and prodigiosin antibiotics, and infection in Caenorhabditis elegans, but up‐regulating flagellar motility. Detailed proteomic analysis using TMT peptide labelling and LC–MS/MS revealed that FloR is a physiological master regulator that operates through subordinate pleiotropic regulators including Rap, RpoS, RsmA, PigU, PstS and PigT.
Language and reading development in children learning English as an additional language in primary school in England
Authors: Dixon Chris , Thomson Jenny , Fricke Silke
Published: April 2020

Children learning English as an additional language (EAL) are a growing population of learners in English primary schools. These children begin school with differing levels of English language proficiency and tend to underperform in relation to their non‐EAL peers on measures of English oral language and reading. However, little work has examined the developmental trajectories of these skills in EAL learners in England. EAL learners and 33 non‐EAL peers in Year 4 (age 8–9 years) were assessed at three time points over 18 months on measures of oral language (vocabulary, grammar and listening comprehension), phonological processing (spoonerisms and rapid automatised naming) and reading skills (single‐word decoding and passage reading). At t1, EAL learners scored significantly lower than non‐EAL peers in receptive and expressive vocabulary (breadth but not depth), spoonerisms and passage reading accuracy. Contrary to previous research, no significant group differences were found in listening or reading comprehension skills. With the exception of passage reading accuracy, there was no evidence for convergence or divergence between the groups in rate of progress over time. After three years of English‐medium classroom instruction, EAL learners continue to underperform relative to their non‐EAL peers in breadth of English vocabulary knowledge. This discrepancy in vocabulary knowledge does not appear to narrow as a result of regular classroom instruction in the run up to the final stages of primary school, pinpointing vocabulary as a key target for intervention.