bluuebunny/crossref_metadata_2025 huggingface dataset:
The 22q11.2 region regulates presynaptic gene-products linked to schizophrenia
Authors: Nehme Ralda , Pietiläinen Olli , Artomov Mykyta , Tegtmeyer Matthew , Bell Christina , Ganna Andrea , Singh Tarjinder , Trehan Aditi , Valakh Vera , Sherwood John , Manning Danielle , Peirent Emily , Malik Rhea , Guss Ellen J. , Hawes Derek , Beccard Amanda , Bara Anne M. , Hazelbaker Dane Z. , Zuccaro Emanuela , Genovese Giulio , Loboda Alexander A , Neumann Anna , Lilliehook Christina , Kuismin Outi , Hamalainen Eija , Kurki Mitja , Hultman Christina M. , Kähler Anna K. , Paulo Joao A. , Madison Jon , Cohen Bruce , McPhie Donna , Adolfsson Rolf , Perlis Roy , Dolmetsch Ricardo , Farhi Samouil , McCarroll Steven , Hyman Steven , Neale Ben , Barrett Lindy E. , Harper Wade , Palotie Aarno , Daly Mark , Eggan Kevin
Published: September 2021

To study how the 22q11.2 deletion predisposes to psychiatric disease, we generated induced pluripotent stem cells from deletion carriers and controls, as well as utilized CRISPR/Cas9 to introduce the heterozygous deletion into a control cell line. Upon differentiation into neural progenitor cells, we found the deletion acted in trans to alter the abundance of transcripts associated with risk for neurodevelopmental disorders including Autism Spectrum Disorder. In more differentiated excitatory neurons, altered transcripts encoded presynaptic factors and were associated with genetic risk for schizophrenia, including common (per-SNP heritability p (τc)= 4.2 x 10-6) and rare, loss of function variants (p = 1.29×10-12). These findings suggest a potential relationship between cellular states, developmental windows and susceptibility to psychiatric conditions with different ages of onset. To understand how the deletion contributed to these observed changes in gene expression, we developed and applied PPItools, which identifies the minimal protein-protein interaction network that best explains an observed set of gene expression alterations. We found that many of the genes in the 22q11.2 interval interact in presynaptic, proteasome, and JUN/FOS transcriptional pathways that underlie the broader alterations in psychiatric risk gene expression we identified. Our findings suggest that the 22q11.2 deletion impacts genes and pathways that may converge with risk loci implicated by psychiatric genetic studies to influence disease manifestation in each deletion carrier.
Combinatorial G x G x E CRISPR screening and functional analysis highlights SLC25A39 in mitochondrial GSH transport
Authors: Shi Xiaojian , Reinstadler Bryn , Shah Hardik , To Tsz-Leung , Byrne Katie , Summer Luanna , Calvo Sarah E. , Goldberger Olga , Doench John G. , Mootha Vamsi K. , Shen Hongying
Published: September 2021

The SLC25 carrier family consists of 53 transporters that shuttle nutrients and co-factors across mitochondrial membranes1-3. The family is highly redundant and their transport activities coupled to metabolic state. Here, we introduce a pooled, dual CRISPR screening strategy that knocks out pairs of transporters in four metabolic states — glucose, galactose, OXPHOS inhibition, and absence of pyruvate — designed to unmask the inter-dependence of these genes. In total, we screened 63 genes in four metabolic states, corresponding to 2016 single and pair-wise genetic perturbations. We recovered 19 gene-by-environment (GxE) interactions and 9 gene-by-gene (GxG) interactions. One GxE interaction hit illustrated that the fitness defect in the mitochondrial folate carrier (SLC25A32) KO cells was genetically buffered in galactose due to a lack of substrate in de novo purine biosynthesis. Another GxE interaction hit revealed non-equivalence of the paralogous ATP/ADP exchangers (ANTs) with ANT2 specifically required during OXPHOS inhibition. GxG analysis highlighted a buffering interaction between the iron transporter SLC25A37 and the poorly characterized SLC25A39. Mitochondrial metabolite profiling, organelle transport assays, and structure-guided mutagenesis suggests SLC25A39 is critical for mitochondrial glutathione (GSH) transport. Our work underscores the importance of systemetically investigating family-wide genetic interactions between mitochondrial transporters across many metabolic environments.
Imaging Flow Cytometry reveals a dual role for exopolysaccharides in biofilms: To promote self-adhesion while repelling non-self-community members
Authors: Maan Harsh , Povolotsky Tatyana L. , Porat Ziv , Kolodkin-Gal Ilana
Published: September 2021

In nature, bacteria are establishing differentiated communities referred to as biofilms. These multicellular communities are held together by self-produced polymers that allow the community members to adhere to the surface as well as to neighbor bacteria. Here, we report that exopolysaccharides prevent Bacillus subtilis from co-aggregating with a distantly related bacterium Bacillus mycoides, while maintaining their role in promoting self-adhesion and co-adhesion with phylogenetically related bacterium, Bacillus atrophaeus. The defensive role of the exopolysaccharides is due to the specific regulation of bacillaene. Single cell analysis of biofilm and free-living bacterial cells using imaging flow cytometry confirmed a specific role for the exopolysaccharides in microbial competition repelling B. mycoides. Unlike exopolysaccharides, the matrix protein TasA induced bacillaene but inhibited the expression of the biosynthetic clusters for surfactin, and therefore its overall effect on microbial competition during floating biofilm formation was neutral. Thus, the exopolysaccharides provide a dual fitness advantage for biofilm-forming cells, as it acts to promote co-aggregation of related species, as well as, a secreted cue for chemical interference with non-compatible partners. These results experimentally demonstrate a general assembly principle of complex communities and provides an appealing explanation for how closely related species are favored during community assembly. Furthermore, the differential regulation of surfactin and bacillaene by the extracellular matrix may explain the spatio-temporal gradients of antibiotic production within biofilms.
The short term High Fat Diet sparks gut microbiota associated metabolic syndrome pathogenesis and impact of Amoxicillin intervention in mice
Authors: Kumar Suresh , Saini Vikram , Raj V. Samuel
Published: September 2021

Background

Knowledge about alteration in gut microbiota on a high-fat diet (HFD) and common antibiotics for a short period is little known. The study was undertaken to evaluate the changes in the microbiota profile in HFD fed mice followed by amoxicillin intervention.

Results

For two weeks, the mice were fed with HFD followed by amoxicillin for one week. Animals were evaluated for haemato-biochemical, histopathological and 16S rRNA sequencing followed by bioinformatics analysis to know any changes in gut microbiota ecology. Amoxicillin treatment for a short duration had marked the remarkable remodelling of gut microbiota that directly linked to beneficial impact by countering the pathogenesis of the metabolic syndrome besides overgrowth of particular opportunistic pathogens of gut inflammatory diseases. Amoxicillin treatment significantly decreased blood glucose and a slight elevation in cholesterol levels on blood biochemistry analysis. No marked pathological changes were observed in HFD fed mice.

Conclusions

Our results suggest that Amoxicillin treatment had a beneficial influence on the obese related metabolic syndrome with the risk of hypercholesterolemia and some gut-resistant intestinal pathobionts.
A different mechanism of C-type inactivation in the Kv-like KcsA mutant E71V
Authors: Rohaim Ahmed , Vermeulen Bram J.A. , Li Jing , Kümmerer Felix , Napoli Federico , Blachowicz Lydia , Medeiros-Silva João , Roux Benoit , Weingarth Markus
Published: September 2021

A large class of K+ channels display a time-dependent phenomenon called C-type inactivation whereby prolonged activation by an external stimulus leads to a non-conductive conformation of the selectivity filter. C-type inactivation is of great physiological importance particularly in voltage-activated K+ channels (Kv), affecting the firing patterns of neurons and shaping cardiac action potentials. While understanding the molecular basis of inactivation has a direct impact on human health, its structural basis remains unresolved. Knowledge about C-type inactivation has been largely deduced from the pH-activated bacterial K+ channel KcsA, whose selectivity filter under inactivating conditions adopts a constricted conformation at the level of the central glycine (TTVGYGD) that is stabilized by tightly bound water molecules. However, C-type inactivation is highly sensitive to the molecular environment surrounding the selectivity filter in the pore domain, which is different in Kv channels than in the model KcsA. In particular, a glutamic acid residue at position 71 along the pore helix in KcsA is consistently substituted by a nonpolar valine in most Kv channels, suggesting that this side chain is an important molecular determinant of function. Here, a combination of X-ray crystallography, solid-state NMR and molecular dynamics simulations of the E71V mutant of KcsA is undertaken to explore the features associated with this Kv-like construct. In both X-ray and ssNMR data, it is observed that the filter of the Kv-like KcsA mutant does not adopt the familiar constricted conformation under inactivating conditions. Rather, the filter appears to adopt a conformation that is slightly narrowed and rigidified over its entire length. No structural inactivation water molecules are present. On the other hand, molecular dynamics simulations indicate that the familiar constricted conformation can nonetheless be stably established in the mutant channel. Together, these findings suggest that the Kv-like E71V mutation in the KcsA channel may be associated with different modes of C-type inactivation, showing that distinct selectivity filter environments entail distinct C-type inactivation mechanisms.
Deleterious Mutations Accumulate Faster in Allopolyploid than Diploid Cotton (Gossypium) and Unequally Between Subgenomes
Authors: Conover Justin L. , Wendel Jonathan F.
Published: September 2021

Whole genome duplication (polyploidization) is among the most dramatic mutational processes in nature, so understanding how natural selection differs in polyploids relative to diploids is an important goal. Population genetics theory predicts that recessive deleterious mutations accumulate faster in allopolyploids than diploids due to the masking effect of redundant gene copies, but this prediction is hitherto unconfirmed. Here, we use the cotton genus (Gossypium), which contains seven allopolyploids derived from a single polyploidization event 1-2 million years ago, to investigate deleterious mutation accumulation. We use two methods of identifying deleterious mutations at the nucleotide and amino acid level, along with whole-genome resequencing of 43 individuals spanning six allopolyploid species and their two diploid progenitors, to demonstrate that deleterious mutations accumulate faster in allopolyploids than in their diploid progenitors. We find that, unlike what would be expected under models of demographic changes alone, strongly deleterious mutations show the biggest difference between ploidy levels, and this effect diminishes for moderately and mildly deleterious mutations. We further show that the proportion of nonsynonymous mutations that are deleterious differs between the two co-resident subgenomes in the allopolyploids, suggesting that homoeologous masking acts unequally between subgenomes. Our results provide a genome-wide perspective on classic notions of the significance of gene duplication that likely are broadly applicable to allopolyploids, with implications for our understanding of the evolutionary fate of deleterious mutations. Finally, we note that some measures of selection (e.g. dN/dS, πN/πS) may be biased when species of different ploidy levels are compared.
Reclassification of Shigella species as later heterotypic synonyms of Escherichia coli in the Genome Taxonomy Database
Authors: Parks Donovan H. , Chuvochina Maria , Reeves Peter R. , Beatson Scott A. , Hugenholtz Philip
Published: September 2021

Members of the genus Shigella have high genomic similarity to Escherichia coli and are often considered to be atypical members of this species. In an attempt to retain Shigella species as recognizable entities, they were reclassified as Escherichia species in the Genome Taxonomy Database (GTDB) using an operational average nucleotide identity (ANI)-based approach nucleated around type strains. This resulted in nearly 80% of E. coli genomes being reclassified to new species including the common laboratory strain E. coli K-12 (to ‘E. flexneri’) because it is more closely related to the type strain of Shigella flexneri than it is to the type strain of E. coli. Here we resolve this conundrum by treating Shigella species as later heterotypic synonyms of E. coli, present evidence supporting this reclassification, and show that assigning E. coli/Shigella strains to a single species is congruent with the GTDB-adopted genomic species definition.
A phylogenetically-restricted essential cell cycle progression factor in the human pathogen Candida albicans
Authors: Jaitly Priya , Legrand Mélanie , Das Abhijit , Patel Tejas , Chauvel Murielle , d’Enfert Christophe , Sanyal Kaustuv
Published: September 2021

Chromosomal instability in fungal pathogens caused by cell division errors is associated with antifungal drug resistance. To identify mechanisms underlying such instability and to uncover new potential antifungal targets, we conducted an overexpression screen monitoring chromosomal stability in the human fungal pathogen Candida albicans. Analysis of ~1000 genes uncovered six chromosomal stability (CSA) genes, five of which are related to cell division genes in other organisms. The sixth gene, CSA6, is selectively present in the CUG-Ser clade species that includes C. albicans and other human fungal pathogens. The protein encoded by CSA6 localizes to the spindle pole bodies, is required for exit from mitosis, and induces a checkpoint-dependent metaphase arrest upon overexpression. Together, Csa6 defines an essential CUG-Ser fungal clade-specific cell cycle progression factor, highlighting the existence of phylogenetically-restricted cell division genes which may serve as potential unique therapeutic targets.

Teaser

Csa6 is essential for mitotic progression and mitotic exit in the human fungal pathogen Candida albicans.
RIG-I uses its intrinsically disordered CARDs-Helicase linker in RNA proofreading functions
Authors: Schweibenz Brandon D. , Devarkar Swapnil C. , Solotchi Mihai , Zhang Jie , Pascal Bruce D. , Griffin Patrick R. , Patel Smita S.
Published: September 2021

The innate immune receptor RIG-I provides the first line of defense against viral infections. Viral RNAs are recognized by the C-terminal domain (CTD) of RIG-I, but the RNA must engage the helicase domain to release the signaling domain CARDs from their autoinhibitory CARD2:Hel2i interactions. Because the helicase lacks RNA specificity, there must be mechanisms to proofread RNAs entering the helicase domain. Although such mechanisms are crucial in preventing aberrant immune responses by non-specific RNAs, they remain largely unknown. This study reveals a previously unknown proofreading mechanism that RIG-I uses to ensure the helicase engages RNAs chosen explicitly by the CTD. A crucial part of this mechanism involves the intrinsically disordered CARDs-Helicase Linker (CHL), which uses its negatively charged regions to electrostatically antagonize incoming RNAs. In addition to RNA gating, CHL is essential in stabilizing the CARD2:Hel2i interface. The CHL and CARD2:Hel2i interface work together, establishing a tunable gating mechanism that allows CTD-chosen RNAs to bind into the helicase while blocking non-specific RNAs. With its critical regulatory functions, CHL represents a novel target for RIG-I-based therapeutics.
Molecular mechanisms associated with clustered lesion-induced impairment of 8-oxoG recognition by the human glycosylase OGG1
Authors: Jiang Tao , Monari Antonio , Dumont Elise , Bignon Emmanuelle
Published: September 2021

The 8-oxo-7,8-dihydroguanine, referred to as 8-oxoG, is a highly mutagenic DNA lesion that can provoke the appearance of mismatches if it escapes the DNA Damage Response. The specific recognition of its structural signature by the hOGG1 glycosylase is the first step along the Base Excision Repair pathway, that ensures the integrity of the genome by preventing the emergence of mutations. 8-oxoG formation, structural features and repair have been the matter of extensive research and more recently this active field of research expended to the more complicated case of 8-oxoG within clustered lesions. Indeed, the presence of a second lesion within 1 or 2 helix turns can dramatically impact the repair yields of 8-oxoG by glycosylases. In this work, we use μs-range molecular dynamics simulations and machine learning-based post-analysis to explore the molecular mechanisms associated with the recognition of 8-oxoG by hOGG1 when embedded in a multiple lesions site with a mismatch in 5’ or 3’. We delineate the stiffening of the DNA-protein interactions upon the presence of the mismatches, and rationalize the much lower repair yields reported with a 5’ mismatch by describing the perturbation of 8-oxoG structural features upon addition of an adjacent lesion.
Computationally designed GPCR quaternary structures bias signaling pathway activation
Authors: Paradis J. S. , Feng X. , Murat B. , Jefferson R. , Szpakowska M. , Hogue M. , Bergkamp N. D. , Heydenreich F.M. , Smit M. J. , Chevigne A. , Bouvier M. , Barth P.
Published: September 2021

Communication across membranes controls critical cellular processes and is achieved by receptors translating extracellular signals into selective cytoplasmic responses. While receptor tertiary structures can now be readily characterized, receptor associations into quaternary structures are very challenging to study and their implications in signal transduction remain poorly understood. Here, we report a computational approach for predicting membrane receptor self-associations, and designing receptor oligomers with various quaternary structures and signaling properties. Using this approach, we designed chemokine receptor CXCR4 dimers with reprogrammed stabilities, conformations, and abilities to activate distinct intracellular signaling proteins. In agreement with our predictions, the designed CXCR4s dimerized through distinct conformations and displayed different quaternary structural changes upon activation. Consistent with the active state models, all engineered CXCR4 oligomers activated the G protein Gi, but only a few specific dimer structures also recruited β-arrestins. Overall, we demonstrate that quaternary structures represent an important unforeseen mechanism of receptor biased signaling and reveal the existence of a conformational switch at the dimer interface of several G protein-coupled receptors including CXCR4, mu-Opioid and type-2 Vasopressin receptors that selectively control the activation of G proteins vs β-arrestin-mediated pathways. The approach should prove useful for predicting and designing receptor associations to uncover and reprogram selective cellular signaling functions.
Transcriptome and miRNAome reveal components regulating primary thickening of bamboo shoots
Authors: Li Ying , Zhang Deqiang , Lou Yongfeng , Xinmin An , Gao Zhimin
Published: September 2021

Primary thickening determines bamboo yield and wood property. However, little is known about the regulatory networks involved in this process. The present study identified a total of 58,652 genes and 521 miRNAs via transcriptome and small RNA sequencing using the underground thickening shoot samples of wild type (WT) Moso bamboo (Phyllostachys edulis) and a thick wall (TW) variant (P. edulis cv. Pachyloen) at five developmental stages (WTS1/TWS1-WTS5/TWS5). A total of 11,636 (54.05%) differentially expressed genes (DEGs) and 515 (98.85%) differentially expressed miRNAs (DEmiRs) were identified from the WT, TW, and WTTW groups. The first two groups were composed of four pairwise combinations each between two successive stages (WTS2/TWS2_vs_WTS1/TWS1, WTS3/TWS3_vs_WTS2/TWS2, WTS4/TWS4_vs_WTS3/TWS3 and WTS5/TWS5_vs_WTS4/TWS4), and the WTTW group was composed of five between two relative stages (TWS1–5_vs_WTS1–5). Additionally, among the phytohormones, zeatin (ZT) showed more remarkable changes in concentrations than indole-3-acetic acid (IAA), gibberellic acid (GA3), and abscisic acid (ABA) throughout the five stages in the WT and the TW groups. Moreover, 118 sites were identified for 590 miRNA-mRNA pairs via degradome sequencing. The dual-luciferase reporter assay confirmed that 14 miRNAs bound to 12 targets. Fluorescence in situ hybridization (FISH) localized miR166 and miR160 in the shoot apical meristem (SAM) and the procambium of Moso bamboo shoots at the S1 stage. Thus, primary thickening is a complex process regulated by miRNA-gene-phytohormone networks, and the miRNAome and transcriptome dynamics regulate phenotypic plasticity. These findings provide insights into the molecular mechanisms underlying wood formation and properties and propose targets for bamboo breeding.
Internal oligo(dT) priming in bulk and single cell RNA sequencing
Authors: Svoboda Marek , Frost H. Robert , Bosco Giovanni
Published: September 2021

Significant advances in RNA sequencing have been recently made possible by the use of oligo(dT) primers for simultaneous mRNA enrichment and reverse transcription priming. The associated increase in efficiency has enabled more economical bulk RNA sequencing methods as well as the advent of high throughput single cell RNA sequencing, now already one of the most widely adopted new methods in the study of transcriptomics. However, the effects of off-target oligo(dT) priming on gene expression quantification have not been fully appreciated. In the present study, we describe the extent, the possible causes, and the consequences of internal oligo(dT) priming across multiple publicly available datasets obtained from a variety of bulk and single cell RNA sequencing platforms. In order to explore and address this issue, we developed a computational algorithm for identification of sequencing read alignments that likely resulted from internal oligo(dT) priming and their subsequent removal from the data. Directly comparing filtered datasets to those obtained by an alternative method reveals significant improvements in gene expression measurement. Finally, we infer a list of genes whose expression quantification is most likely to be affected by internal oligo(dT) priming.
Structural basis of substrate recognition and translocation by human ABCD1
Authors: Chen Zhi-Peng , Xu Da , Wang Liang , Zhou Cong-Zhao , Hou Wen-Tao , Chen Yuxing
Published: September 2021

Human ATP-binding cassette (ABC) transporter ABCD1 transports CoA esters of saturated/monounsaturated very long chain fatty acid from cytosol to the peroxisome for β-oxidation. Dysfunction of human ABCD1 usually causes the severe progressive genetic disorder X-linked adrenoleukodystrophy, which eventually affects the adrenal glands and/or the central nervous system. Here, we report three cryo-EM structures of human ABCD1 in various states. The apo-form ABCD1 at 3.53 Å resolution adopts an inward-facing conformation, harboring a phosphatidyl ethanolamine (PE) molecule at each lateral entry of substrate cavity. In the substrate-bound ABCD1 structure at 3.59 Å resolution, two molecules of C22:0-CoA (one of the physiological substrates of ABCD1) is symmetrically bound to the transmembrane domains (TMDs). Each C22:0-CoA adopts an unpresented L-shape configuration: the CoA portion inserts into a polar pocket at the TMD at a pose parallel to the membrane plane, whereas the acyl chain portion perpendicular to membrane plane is embedded in a hydrophobic pocket at the opposite TMD. Upon binding the two C22:0-CoA molecules, which resemble a pair of hinges crossing the two TMDs, the two nucleotide-binding domains (NBDs) of ABCD1 approach towards each other. Addition ATP to the substrate-bound ABCD1 enabled us to reveal an ATP-bound structure at 2.79 Å, which shows an outward-facing conformation with the dimerized NBDs succeeding substrate release. These three structures combined with biochemical assays exhibit a snapshot of ABCD1-mediated substrate recognition, translocation and release. These findings provide the structural insights into the transport mechanism of ABC transporters that transport amphipathic molecules with long acyl chains.
Using photocaging for fast time-resolved structural biology studies
Authors: Monteiro Diana C. F. , Amoah Emmanuel , Rogers Cromarte , Pearson Arwen R.
Published: September 2021

Careful selection of photocaging approaches is critical to achieve fast and well synchronized reaction initiation and perform successful time-resolved structural biology experiments. This review summarizes the best characterized and most relevant photocaging groups previously described in the literature. It also provides a walkthrough of the essential factors to consider in designing a suitable photocaged molecule to address specific biological questions, focusing on photocaging groups with well characterized spectroscopic properties. The relationships between decay rates (kin s−1), quantum yields (φ) and molar extinction coefficients (ɛmaxinM−1 cm−1) are highlighted for different groups. The effects of the nature of the photocaged group on these properties is also discussed. Four main photocaging scaffolds are presented in detail,o-nitrobenzyls,p-hydroxyphenyls, coumarinyls and nitrodibenzofuranyls, along with three examples of the use of this technology. Furthermore, a subset of specialty photocages are highlighted: photoacids, molecular photoswitches and metal-containing photocages. These extend the range of photocaging approaches by, for example, controlling pH or generating conformationally locked molecules.
Unmanned aerial vehicles (UAV) as a tool for visual inspection of building facades in AEC+FM industry
Authors: Ruiz Ramiro Daniel Ballesteros , Lordsleem Jr. Alberto Casado , Rocha Joaquin Humberto Aquino , Irizarry Javier
Published: September 2021

Purpose

The purpose of this paper is to report on the results of an exploratory study on the use of unmanned aerial vehicles (UAV) as a visual data collection tool in the architecture, engineering, construction and facility management industry for the inspection of pathological manifestations in building facades.

Design/methodology/approach

The methodology used a field research experimental approach, where three case studies were carried out involving buildings of medium and high elevation. The protocol of activities included image collection and processing stages, as well as detailed analysis of the collected visual data for the identification of pathological manifestations in building facades.

Findings

The findings emphasize the technical feasibility and efficacy of inspections with UAV, showing that among the visual assets produced, digital photographs collected with the aircraft were more effective for the detection of pathologies when compared to the three-dimensional models and orthomosaics generated by digital photogrammetry software.

Originality/value

The research has formulated the protocol for the inspection of facades using UAV and the comparative analysis of visual assets that can be generated for inspection purposes.
Fourth kind Chebyshev Wavelet Method for the solution of multi-term variable order fractional differential equations
Authors: Turan Dincel Arzu , Tural Polat Sadiye Nergis
Published: September 2021

Purpose

Multi-term variable-order fractional differential equations (VO-FDEs) are powerful tools in accurate modeling of transient-regime real-life problems such as diffusion phenomena and nonlinear viscoelasticity. In this paper the Chebyshev polynomials of the fourth kind is employed to obtain a numerical solution for those multi-term VO-FDEs.

Design/methodology/approach

To this end, operational matrices for the approximation of the VO-FDEs are obtained using the Fourth kind Chebyshev Wavelets (FKCW). Thus, the VO-FDE is condensed into an algebraic equation system. The solution of the system of those equations yields a coefficient vector, the coefficient vector in turn yields the approximate solution.

Findings

Several examples that we present at the end of the paper emphasize the efficacy and preciseness of the proposed method.

Originality/value

The value of the paper stems from the exploitation of FKCWs for the numerical solution of multi-term VO-FDEs. The method produces accurate results even for relatively small collocation points. What is more, FKCW method provides a compact mapping between multi-term VO-FDEs and a system of algebraic equations given in vector-matrix form.
An investigation into challenges and opportunities in the Australian construction and demolition waste management system
Authors: Shooshtarian Salman , Caldera Savindi , Maqsood Tayyab , Ryley Tim , Khalfan Malik
Published: September 2021

Purpose

The literature shows that the current Australian waste management framework does not meet industry and government expectations. This study, therefore, seeks the key construction and demolition (C&D) stakeholders' insights on various issues identified. It aims to understand the main barriers to effective C&D waste management, examining the role of the federal government and exploring perceptions around waste regulations, policies and schemes.

Design/methodology/approach

An online survey was conducted in 2019 to capture stakeholder perceptions. One hundred and thirty-two participants from various industries and government agencies representing Australian jurisdictions took part in the survey. Quantitative and qualitative data were collected.

Findings

The results show that the main barriers are “overregulation, tough acceptance criteria and increased testing requirements”, “lack of local market” and “culture, poor education and low acceptance”. The main areas of improvement include “providing a guideline that determines the accepted level of contamination for reusing C&D waste”, “preparation of guidelines on requirements of using recycled C&D materials in different industries” and “setting a target for reduction, reusing and recycling C&D waste”.

Research limitations/implications

Some research findings may not be generalisable beyond Australia, but there are interesting insights for an international audience. The results inform policy development within the Australian states and territories context, to support the design and implementation of a circular economy model in the construction industry. The findings are evidence for a broader discussion to solve prevailing issues in C&D waste management, notably in the context of construction materials' end of life management.

Practical implications

The study highlights that policy development needs to be further expanded to include new/current waste management schemes including manufacturer's shared responsibility of waste generation, subsidies for C&D waste recycled materials and the proximity principle.

Originality/value

This paper provides a clear insight into C&D waste management stakeholders' perceptions towards the current waste management system in Australia.
Internships before and during COVID-19: experiences and perceptions of undergraduate interns and supervisors
Authors: Teng Cecilia Woon Chien , Lim Raymond Boon Tar , Chow Dana Wai Shin , Narayanasamy Suganthi , Liow Chee Hsiang , Lee Jeannette Jen-Mai
Published: September 2021

Purpose

The COVID-19 pandemic has brought about a contingent shift to remote working and learning worldwide. However, little is known regarding the impact of this shift on internships. Moreover, much of the available literature studies on internships are focused largely on perceptions by students, less so by supervisors. This paper describes the impact of COVID-19 on public health (PH) internships and examines interns' and supervisors' perspectives on their experiences in internships before and during the pandemic.

Design/methodology/approach

A cross-sectional study design was conducted on two cohorts of undergraduate students and their supervisors in Singapore. Participants were surveyed using questionnaires with both close-ended and open-ended questions about various aspects of the internship experience. Data were triangulated from these surveys and module evaluation reports, and analyzed quantitatively and qualitatively.

Findings

COVID-19 disrupted internships significantly, with a reduction in the number of placements offered and necessary changes to the internship scope. Overall, the internship experience has been positive. Supervisors and e-interns reported high levels of satisfaction and documented learning gains such as the development of technical skills and soft skills unique to remote work.

Originality/value

The study findings fill current gaps in the literature on supervisor perceptions and internship experiences during COVID-19. Recommendations are proposed to optimize e-internships, a potentially authentic workplace in the post-COVID era.
Characteristics of generalized Fourier’s heat flux and homogeneous-heterogeneous reactions in 3D flow of non-Newtonian cross fluid
Authors: Ali Mehboob , Sultan F. , Khan Waqar Azeem , Shahzad M. , Arif Hina , Irfan M.
Published: September 2021

Purpose

The purpose of this paper is to investigate the heat transportation rate by using Cattaneo–Christov heat flux model. Furthermore, homogeneous-heterogeneous reaction is also deliberated in the modeling of concentration expression.

Design/methodology/approach

The nonlinear PDEs are reduced to ODEs via implementation of applicable transformations. Numerical scheme bvp4c is used to obtain convergent solutions.

Findings

The main findings are to characterize the generalized Fourier’s heat flux and homogeneous-heterogeneous reactions in 3D flow of non-Newtonian cross fluid.

Originality/value

It is to certify that this paper is neither published earlier nor submitted elsewhere.
Poverty prevalence and negative spillovers in Sub-Saharan Africa: a focus on extreme and multidimensional poverty in the region
Authors: Olaoye Olumide , Ibukun Cleopatra Oluseye , Razzak Mustafa , Mose Naftaly
Published: September 2021

Purpose

The paper analyses the prevalence of extreme and multidimensional poverty in line with the sustainable development agenda. In addition, the paper examines the drivers of extreme poverty while accounting for the potential spillover effect of poverty in the region.

Design/methodology/approach

The study adopts the pooled OLS with Discroll-Kraay robust standard errors to control for cross-sectional dependence. In addition, given the strong potential for endogeneity of poverty index, the authors also employ the generalized method of moments (GMM), which accounts for simultaneity and endogeneity problems, and the spatial error and lag models to control for all forms of spatial and temporal dependence since the factors that affect poverty disperse across borders.

Findings

The study finds that in addition to the traditional drivers of poverty (unemployment, low per capita GDP growth and public debt), poverty in Sub-Saharan Africa is a symptom of a deeper structural problem (lack of access to water and sanitation, high level of corruption and low level of financial development, and frequent economic busts). Likewise, the results from the spatial econometric specification show, consistently across all the specifications, that there is a substantial spillover effect of poverty across the region.

Originality/value

The main novelty of the paper is that the authors investigate the “economic shrinkage hypothesis,” and examined the potential negative spillover effect of poverty in the region.
Conspicuous consumption: impact of narcissism and need for uniqueness on self-brand and communal-brand connection with public vs private use brands
Authors: Fazli-Salehi Reza , Torres Ivonne M. , Madadi Rozbeh , Zúñiga Miguel Ángel
Published: September 2021

Purpose

The purpose of this study was to explore the impact of self-related traits on consumer self-brand connection (SBC) and communal-brand connection (CBC) in public vs private consumption. Marketing practitioners will benefit by understanding the consumer traits that can be triggered and focused on in advertising campaigns. Moreover, it is important to know which traits have a significant impact on each product category section (i.e. public vs private use).

Design/methodology/approach

An experiment used a between-subjects design with two randomized blocks of publicly used brands and privately used brands. Within each block, the relationship between independent variables (narcissism and need for uniqueness [NFU]) and dependent variables (SBC, CBC and purchase intention) were analyzed using SmartPLS.

Findings

The results showed that narcissism has a significant positive impact on consumers’ SBC for publicly consumed products, no effect was found for CBC. NFU shows a significant positive impact on SBC and CBC for both categories. The results also showed a positive impact for SBC on purchase intention, no effect was found for CBC.

Research limitations/implications

Future research can examine brand names that people favor the most and test whether individuals’ narcissism and NFU is influential on their SBC and CBC with the brands, regardless of the exposure to the visual cues provided in this paper. Moreover, there are more behavioral outcomes that need examination. For example, it would be fruitful to see whether attitude toward the ad, or brand attitude are affected by consumers’ narcissism and NFU.

Practical implications

The results contribute to the effectiveness of advertising in different industries. For instance, brand managers and marketing practitioners can benefit by understanding which product types are more attractive to consumers based on their tendency toward uniqueness. Moreover, narcissism is another common trait that can be used to target consumers. Thus, certain product types may be more attractive to consumers based on their narcissism tendencies.

Originality/value

Despite the popularity of SBC and CBC research, there is limited knowledge about the consumer traits which can stimulate and enhance these concepts. As such, an important question that needs to be addressed is: “What consumer personality traits lead to higher SBC and CBC?” When it comes to self-concept, a limited number of studies exist that explore the actual types of personality or self-concept that generate a desired connection between the “self” and brands.
Leveraging blockchain technology for circularity in agricultural supply chains: evidence from a fast-growing economy
Authors: Sharma Rohit , Samad Taab Ahmad , Chiappetta Jabbour Charbel Jose , de Queiroz Mauricio Juca
Published: September 2021

Purpose

The authors originally explore the factors for blockchain technology (BCT) adoption in agricultural supply chains (ASCs) to enhance circularity and understand the dependencies, hierarchical structure and causalities between these factors.

Design/methodology/approach

Based on an extant literature review and expert opinion, the present study identified ten enablers for adopting BCT to leverage the circular economy (CE) practices in the ASCs. Then, using an integrated interpretive structural modeling and decision-making trial and evaluation laboratory (ISM-DEMATEL) approach, hierarchical and cause–effect relationships are established.

Findings

It was observed that traceability is the most prominent enabler from the CE perspective in ASCs. However, traceability, being a net effect enabler, will be realized through the achievement of other cause enablers, such as seamless connectivity and information flow and decentralized and distributed ledger technology. The authors also propose a 12 Rs framework for enhancing circularity in ASC operations.

Research limitations/implications

The paper identifies enablers to BCT adoption that will enhance circularity in ASC operations. The ISM hierarchical model is based on the driving and dependence powers of the enablers, and DEMATEL aids in identifying causal relationships among the enablers.

Practical implications

The study's findings and proposed 12 Rs framework may help the practitioners and policymakers devise effective BCT implementation strategies in ASCs, thereby empowering sustainability and circularity.

Originality/value

This study enriches the literature by identifying and modeling enablers for BCT adoption in ASCs. The study also proposes a new 12 Rs framework to help enhance ASC circularity.
Volatility discovery in cryptocurrency markets
Authors: Dimpfl Thomas , Elshiaty Dalia
Published: September 2021

Purpose

Cryptocurrency markets are notoriously noisy, but not all markets might behave in the exact same way. Therefore, the aim of this paper is to investigate which one of the cryptocurrency markets contributes the most to the common volatility component inherent in the market.

Design/methodology/approach

The paper extracts each of the cryptocurrency's markets' latent volatility using a stochastic volatility model and, subsequently, models their dynamics in a fractionally cointegrated vector autoregressive model. The authors use the refinement of Lien and Shrestha (2009, J. Futures Mark) to come up with unique Hasbrouck (1995, J. Finance) information shares.

Findings

The authors’ findings indicate that Bitfinex is the leading market for Bitcoin and Ripple, while Bitstamp dominates for Ethereum and Litecoin. Based on the dominant market for each cryptocurrency, the authors find that the volatility of Bitcoin explains most of the volatility among the different cryptocurrencies.

Research limitations/implications

The authors’ findings are limited by the availability of the cryptocurrency data. Apart from Bitcoin, the data series for the other cryptocurrencies are not long enough to ensure the precision of the authors’ estimates.

Originality/value

To date, only price discovery in cryptocurrencies has been studied and identified. This paper extends the current literature into the realm of volatility discovery. In addition, the authors propose a discrete version for the evolution of a markets fundamental volatility, extending the work of Diaset al.(2018).
Media use, political trust and attitude toward direct democracy: empirical evidence from Taiwan
Authors: Chang Wen-Chun
Published: September 2021

Purpose

This study examines the roles of the Internet and other types of media use in explaining the support for direct democracy and further investigates the mediation of political trust in the relationship between media use and the attitude toward direct democracy.

Design/methodology/approach

Using data drawn from Taiwan Social Change Survey 2014 and the approach of structural equation model framework, this study identifies the indirect effects of the Internet and other types of media use on the attitude toward referendums.

Findings

The results of this study show that the frustration resulting from the process of representative politics dominated by political elites is associated with the support for direct democracy as an effective alternative to generate political influences in the formation of public policies.

Originality/value

The advances in the Internet and information technology have expanded the possible platforms of obtaining political information and enabled people to rapidly access political information at lower costs. It is expected that Internet use has altered the relationships among citizens, political parties and the government, potentially influencing citizens' political trust and their attitude toward direct democracy.
Forest soil acidification consistently reduces litter decomposition irrespective of nutrient availability and litter type
Authors: Shen Ying , Tian Dashuan , Hou Jihua , Wang Jinsong , Zhang Ruiyang , Li Zhaolei , Chen Xinli , Wei Xuehong , Zhang XinYu , He Yicheng , Niu Shuli
Published: September 2021

Nitrogen (N), phosphorus (P) and acid deposition are co‐occurring in many ecosystems, likely with complex interactive effects on litter decomposition.

Few studies have been conducted to distinguish the interactive effects of these three factors on forest litter decomposition. Thus, we performed a 5‐year litter decomposition experiment with N, P, acid addition in a temperate forest of Changbai Mountain in China, including four litter types from Pinus koraiensis, Quercus mongolica, Tilia amurensis and their mixtures.

Our results showed that acid addition consistently reduced litter decomposition rate, irrespective of nutrient addition or litter types. In contrast, N and P addition had less impact on litter decomposition. Litter decomposition rate linearly reduced with decreasing soil pH, but positively increased with soil N availability. No relationship was found between soil P availability and litter decomposition. Soil enzyme activity played a key role in regulating litter decomposition response, such as acid phosphatase, xylosidase, N‐cacetyl‐b‐D‐glucosaminidase and α‐1,4 glucosidase. Besides, low‐quality litter (i.e. high C concentration, C:N and C:P ratio) amplified the negative effect of soil acidification on litter decomposition.

This study suggests that soil acidification consistently decelerates litter decomposition in temperate forests, which is independent of soil nutrient availability and litter types. The intensifying soil acidification with continuous N deposition in the future will greatly reduce litter nutrient return to soil, increasing the risk of multiple soil nutrient limitation.

A free Plain Language Summary can be found within the Supporting Information of this article.
Distinguishing between unreliability and dishonesty: A comparative study of aggressive communication in crayfish
Authors: Graham Zackary A. , Angilletta Michael J.
Published: September 2021

A major challenge in the study of animal communication is distinguishing whether signals convey honest or dishonest information. Biologists infer the honesty of a signal from its correlation with the information being signalled (e.g. fecundity or fighting ability)—the better the correlation, the more honest the signal.

However, this view of signalling potentially conflates unreliable indicators with dishonest signals. Just because a trait conveys unreliable information does not mean that the structure serves as a dishonest signal; developmental noise, genetic drift and environmental constraints can reduce the covariation between a putative signal and an organism's quality. Moreover, a trait must influence the behaviour of other organisms to qualify as a signal.

We studied how a putative signal, claw size, affects physical performance and social dominance in three species of stream‐dwelling crayfish, which fight routinely over resources. For comparison, we measured the relationship between claw size and claw strength in three species of burrowing crayfish, which do not fight.

In all species, crayfish with larger claws were not necessarily stronger, indicating that claw size poorly indicates claw strength. However, claw size is unlikely to function as a dishonest signal of fighting ability in these species for two reasons. First, claw size unreliably indicates claw strength in both the stream‐dwelling species and the burrowing species. Second, relative claw size poorly predicted whether stream‐dwelling crayfish would escalate aggression, questioning whether claw size serves as a signal. Instead, stream‐dwelling crayfish escalated aggression based on their relative body size.

Our results highlight the importance of observing behaviour when determining the honesty of a signal. As such, future studies must distinguish between phenotypes that are unreliable indicators (or reliable indicators) from phenotypes that have been selected for dishonest (or honest) signalling.

A free Plain Language Summary can be found within the Supporting Information of this article.