bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal discrimination from the interaction between dynamic synapses and intrinsic subthreshold oscillations
Authors: Torres Joaquin J. , Baroni Fabiano , Latorre Roberto , Varona Pablo
Published: August 2019

The interaction between synaptic and intrinsic dynamics can efficiently shape neuronal input-output relationships in response to temporally structured spike trains. We use a neuron model with subthreshold oscillations receiving inputs through a synapse with short-term depression and facilitation to show that the combination of intrinsic subthreshold and synaptic dynamics leads to channel-specific nontrivial responses and recognition of specific temporal structures. We employ the Generalized Integrate-and-Fire (GIF) model, which can be subjected to analytical characterization. We map the temporal structure of spike input trains to the type of spike response, and show how the emergence of nontrivial input-output preferences is modulated by intrinsic and synaptic parameters in a synergistic manner. We demonstrate that these temporal input discrimination properties are robust to noise and to variations in synaptic strength, suggesting that they likely contribute to neuronal computation in biological circuits. Furthermore, we also illustrate the presence of these input-output relationships in conductance-based models.

Author summary

Neuronal subthreshold oscillations underlie key aspects of information processing in single neuron and network dynamics. Dynamic synapses provide a channel-specific temporal modulation of input information. We combine a neuron model that displays subthreshold oscillations and a dynamic synapse to analytically assess their interplay in processing trains of spike-mediated synaptic currents. Our results show that the co-action of intrinsic and synaptic dynamics builds nontrivial input-output relationships, which are resistant to noise and to changes in synaptic strength. The discrimination of a precise temporal structure of the input signal is shaped as a function of the joint interaction of intrinsic oscillations and synaptic dynamics. This interaction can result in channel-specific recognition of precise temporal patterns, hence greatly expanding the flexibility and complexity in information processing achievable by individual neurons with respect to temporal discrimination mechanisms based on intrinsic neuronal dynamics alone.
Multi-model preclinical platform predicts clinical response of melanoma to immunotherapy
Authors: Pérez-Guijarro Eva , Yang Howard H. , Araya Romina E. , El Meskini Rajaa , Michael Helen T. , Vodnala Suman Kumar , Marie Kerrie L. , Graff-Cherry Cari , Chin Sung , Iacovelli Anthony J. , Kulaga Alan , Fon Anyen , Michalowski Aleksandra M. , Hugo Willy , Lo Roger S. , Restifo Nicholas P. , Van Dyke Terry , Sharan Shyam K. , Goldszmid Romina S. , Ohler Zoe Weaver , Lee Maxwell P. , Day Chi-Ping , Merlino Glenn
Published: August 2019

Although immunotherapy has revolutionized cancer treatment, only a subset of patients demonstrates durable clinical benefit. Definitive predictive biomarkers and targets to overcome resistance remain unidentified, underscoring the urgency to develop reliable immunocompetent models for mechanistic assessment. Here we characterize a panel of syngeneic mouse models representing the main molecular and phenotypic subtypes of human melanomas and exhibiting their range of responses to immune checkpoint blockade (ICB). Comparative analysis of genomic, transcriptomic and tumor-infiltrating immune cell profiles demonstrated alignment with clinical observations and validated the correlation of T cell dysfunction and exclusion programs with resistance. Notably, genome-wide expression analysis uncovered a melanocytic plasticity signature predictive of patient outcome in response to ICB, suggesting that the multipotency and differentiation status of melanoma can determine ICB benefit. Our comparative preclinical platform recapitulates melanoma clinical behavior and can be employed to identify new mechanisms and treatment strategies to improve patient care.
Epigenetic age is accelerated in schizophrenia with age- and sex-specific effects and associated with polygenic disease risk
Authors: Ori Anil P.S. , Olde Loohuis Loes M. , Guintivano Jerry , Hannon Eilis , Dempster Emma , St. Clair David , Bass Nick J , McQuillin Andrew , Mill Jonathan , Sullivan Patrick F , Kahn Rene S. , Horvath Steve , Ophoff Roel A.
Published: August 2019

Background

The study of biological age acceleration may help identify at-risk individuals and contribute to reduce the rising global burden of age-related diseases. Using DNA methylation (DNAm) clocks, we investigated biological aging in schizophrenia (SCZ), a severe mental illness that is associated with an increased prevalence of age-related disabilities and morbidities. In a multi-cohort whole blood sample consisting of 1,090 SCZ cases and 1,206 controls, we investigated differential aging using three DNAm clocks (i.e. Hannum, Horvath, Levine). These clocks are highly predictive of chronological age and are known to capture different processes of biological aging.

Results

We found that blood-based DNAm aging is significantly altered in SCZ with age- and sex-specific effects that differ between clocks and map to distinct chronological age windows. Most notably, differential phenotypic age (Levine clock) was most pronounced in female SCZ patients in later adulthood compared to matched controls. Female patients with high SCZ polygenic risk scores (PRS) present the highest age acceleration in this age group with +4.30 years (CI: 2.40-6.20, P=1.3E-05). Phenotypic age and SCZ PRS contribute additively to the illness and together explain up to 22.4% of the variance in disease status in this study. This suggests that combining genetic and epigenetic predictors may improve predictions of disease outcomes.

Conclusions

Since increased phenotypic age is associated with increased risk of all-cause mortality, our findings indicate that specific and identifiable patient groups are at increased mortality risk as measured by the Levine clock. These results provide new biological insights into the aging landscape of SCZ with age- and sex-specific effects and warrant further investigations into the potential of DNAm clocks as clinical biomarkers that may help with disease management in schizophrenia.
Analysis of single-cell RNA sequencing data based on autoencoders
Authors: Tangherloni Andrea , Ricciuti Federico , Besozzi Daniela , Liò Pietro , Cvejic Ana
Published: August 2019

Background

Single-cell RNA sequencing (scRNA-Seq) experiments are gaining ground to study the molecular processes that drive normal development as well as the onset of different pathologies. Finding an effective and efficient low-dimensional representation of the data is one of the most important steps in the downstream analysis of scRNA-Seq data, as it could provide a better identification of known or putatively novel cell-types. Another step that still poses a challenge is the integration of different scRNA-Seq datasets. Though standard computational pipelines to gain knowledge from scRNA-Seq data exist, a further improvement could be achieved by means of machine learning approaches.

Results

Autoencoders (AEs) have been effectively used to capture the non-linearities among gene interactions of scRNA-Seq data, so that the deployment of AE-based tools might represent the way forward in this context. We introduce here scAEspy, a unifying tool that embodies: (1) four of the most advanced AEs, (2) two novel AEs that we developed on purpose, (3) different loss functions. We show that scAEspy can be coupled with various batch-effect removal tools to integrate data by different scRNA-Seq platforms, in order to better identify the cell-types. We benchmarked scAEspy against the most used batch-effect removal tools, showing that our AE-based strategies outperform the existing solutions.

Conclusions

scAEspy is a user-friendly tool that enables using the most recent and promising AEs to analyse scRNA-Seq data by only setting up two user-defined parameters. Thanks to its modularity, scAEspy can be easily extended to accommodate new AEs to further improve the downstream analysis of scRNA-Seq data. Considering the relevant results we achieved, scAEspy can be considered as a starting point to build a more comprehensive toolkit designed to integrate multi single-cell omics.
Identification of essential oils with activity against stationary phase Staphylococcus aureus
Authors: Xiao Shuzhen , Cui Peng , Shi Wanliang , Zhang Ying
Published: August 2019

Staphylococcus aureus is the most dominant human pathogen, responsible for a variety of chronic and severe infections. There is mounting evidence that persisters are associated with treatment failure and relapse of persistent infections. While some essential oils were reported to have antimicrobial activity against growing S. aureus, activity of essential oils against the non-growing stationary phase S. aureus enriched in persisters has not been investigated. In this study, we evaluated the activity of 143 essential oils against stationary phase S. aureus and identified 39 essential oils (Cinnamon bark, Oregano, Thyme white, Bandit “Thieves”, Lemongrass (Cymbopogon flexuosus), Sandalwood oil, Health shield, Allspice, Amyris, Palmarosa, Cinnamon leaf, Clove bud, Citronella, Geranium bourbon, Marjoram, Peppermint, Lemongrass (Cymbopogon citratus), Cornmint, Elemi, Ho wood, Head ease, Lemon eucalyptus, Litsea cubeba, Myrrh, Parsley seed, Coriander oil, Dillweed, Hyssop, Neroli, Rosewood oil, Tea tree, Cajeput, Glove bud, Lavender, Sleep tight, Vetiver, Palo santo, Sage oil, Yarrow) at 0.5% concentration, 10 essential oils (Cinnamon bark, Oregano, Thyme white, Bandit “Thieves”, Lemongrass (Cymbopogon flexuosus), Sandalwood oil, Health shield, Allspice, Amyris, Palmarosa) at 0.25% concentration, and 7 essential oils (Cinnamon bark, Oregano, Thyme white, Lemongrass (Cymbopogon flexuosus), Allspice, Amyris, Palmarosa) at 0.125% concentration to have high activity against stationary phase S. aureus with no visible growth on agar plates after five-day exposure. Among the 10 essential oils which showed high activity at 0.25% concentration, 9 (Cinnamon bark, Oregano, Thyme white, Bandit “Thieves”, Lemongrass (Cymbopogon flexuosus), Health shield, Allspice, Palmarosa, Amyris) showed higher activity than the known persister drug tosufloxacin, while the other one (Sandalwood oil) was found to be active at a higher concentration. In Oregano essential oil drug combination studies with clinical antibiotics, Oregano plus quinolone drugs (tosufloxacin, levofloxacin, ciprofloxacin) and rifampin completely eradicated all stationary phase S. aureus cells, but had no apparent enhancement for linezolid, vancomycin, sulfamethoxazole, trimethoprim, azithromycin and gentamicin. Our findings may facilitate development of more effective treatment for persistent S. aureus infections.
Epitranscriptomic regulation of the response to the air pollutant naphthalene in mouse lungs: from the perspectives of specialized translation and tolerance linked to the writer ALKBH8
Authors: Leonardi Andrea , Kovalchuk Nataliia , Yin Lei , Endres Lauren , Evke Sara , Nevins Steven , Martin Samuel , Dedon Peter C. , Melendez J. Andres , Winkle Laura Van , Zhang Qing-Yu , Ding Xinxin , Begley Thomas J.
Published: August 2019

Background

The epitranscriptomic writer Alkylation Repair Homolog 8 (ALKBH8) is a tRNA methyltransferase that modifies the wobble uridine of selenocysteine tRNA to promote the specialized translation, via stop codon recoding, of proteins that contain selenocysteine. Corresponding selenoproteins play critical roles in protecting against reactive oxygen species and environmental stress. Using a novel animal model deficient inAlkbh8, we have investigated the importance of epitranscriptomic systems in the response to naphthalene (NA), an abundant polycyclic aromatic hydrocarbon, glutathione depleter and lung toxicant found in tobacco smoke, gasoline and mothballs.

Objectives

Our goal was to define the molecular reprogramming of Alkbh8 deficient (Alkbh8def)mice and evaluate the roles that the epitranscriptomic writer ALKBH8 and selenoproteins play in mitigating NA-induced toxicity and lung dysfunction.

Methods

We performed basal lung analysis and NA exposure studies using WT,Alkbh8defandCyp2abfgs-nullmice, the latter of which lack the cytochrome P450 enzymes required for NA bioactivation. We characterized gene expression, molecular markers of damage, viability and tolerance to NA.

Results

Under basal conditions, lungs fromAlkbh8defmice have increased oxidation-reduction potential (ORP) and 8-isoprostane levels, and have reprogrammed at the molecular level to display increased stress response transcripts. In addition, the ALKBH8 writer deficient lungs have a decreased GSH/GSSG ratio.Alkbh8defmice are more sensitive to NA than WT, showing higher susceptibility to lung damage both at the cellular and molecular levels. WT mice develop a tolerance to NA after 3 days, defined as resistance to a high challenging dose after repeated exposures, which is absent inAlkbh8defmice, with writer deficient not surviving NA exposure.

Discussion

We conclude that the epitranscriptomic writer ALKBH8 plays a protective role against NA-induced lung dysfunction and promotes NA tolerance. Our work provides an early example of how epitranscriptomic systems can regulate the response to environmental stressin vivo.
A phylogenomic approach reveals a low somatic mutation rate in a long-lived plant
Authors: Orr Adam J. , Padovan Amanda , Kainer David , Külheim Carsten , Bromham Lindell , Bustos-Segura Carlos , Foley William , Haff Tonya , Hsieh Ji-Fan , Morales-Suarez Alejandro , Cartwright Reed A. , Lanfear Robert
Published: August 2019

Somatic mutations can have important effects on the life history, ecology, and evolution of plants, but the rate at which they accumulate is poorly understood, and has been very difficult to measure directly. Here, we demonstrate a novel method to measure somatic mutations in individual plants and use this approach to estimate the somatic mutation rate in a large, long-lived, phenotypically mosaic Eucalyptus melliodora tree. Despite being 100 times larger than Arabidopsis, this tree has a per-generation mutation rate only ten times greater, which suggests that this species may have evolved mechanisms to reduce the mutation rate per unit of growth. This adds to a growing body of evidence that illuminates the correlated evolutionary shifts in mutation rate and life history in plants.
Spatial structure undermines parasite suppression by gene drive cargo
Authors: Bull James J , Remien Christopher H , Gomulkiewicz Richard , Krone Stephen M
Published: August 2019

Gene drives may be used in two ways to curtail vectored diseases. Both involve engineering the drive to spread in the vector population. One approach uses the drive to directly depress vector numbers, possibly to extinction. The other approach leaves intact the vector population but suppresses the disease agent during its interaction with the vector. This second application may use a drive engineered to carry a genetic cargo that blocks the disease agent. An advantage of the second application is that it is far less likely to select vector resistance to block the drive, but the disease agent may instead evolve resistance to the inhibitory cargo. However, some gene drives are expected to spread so fast and attain such high coverage in the vector population that, if the disease agent can evolve resistance only gradually, disease eradication may be feasible. Here we use simple models to show that spatial structure in the vector population can greatly facilitate persistence and evolution of resistance by the disease agent. We suggest simple approaches to avoid some types of spatial structure, but others may be intrinsic to the populations being challenged and difficult to overcome.
Morphology of obligate ectosymbionts revealsParalaxusgen. nov., a new circumtropical genus of marine stilbonematine nematodes
Authors: Scharhauser Florian , Zimmermann Judith , Ott Jörg A. , Leisch Nikolaus , Gruber-Vodicka Harald
Published: August 2019

Stilbonematinae are a subfamily of conspicuous marine nematodes, distinguished by a coat of sulphur-oxidizing bacterial ectosymbionts on their cuticle. As most nematodes, the worm hosts have a simple anatomy and few taxonomically informative characters, and this has resulted in numerous taxonomic reassignments and synonymizations. Recent studies using a combination of morphological and molecular traits have helped to improve the taxonomy of Stilbonematinae but also raised questions on the validity of several genera. Here we describe a new circumtropically distributed genusParalaxus(Stilbonematinae) with three species: Paralaxus cocos sp. nov.,P. bermudensissp. nov. andP. columbaesp. nov.. We used single worm metagenomes to generate host 18S rRNA and cytochrome oxidase I (COI) as well as symbiont 16S rRNA gene sequences. Intriguingly, COI alignments and primer matching analyses suggest that the COI is not suitxable for PCR-based barcoding approaches in Stilbonematinae as the genera have a highly diverse base composition and no conserved primer sites. The phylogenetic analyses of all three gene sets however confirm the morphological assignments and support the erection of the new genusParalaxusas well as corroborate the status of the other stilbonematine genera.Paralaxusmost closely resembles the stilbonematine genusLaxusin overlapping sets of diagnostic features but can be distinguished fromLaxusby the morphology of the genus-specific symbiont coat. Our re-analyses of key parameters of the symbiont coat morphology as character for all Stilbonematinae genera show that with amended descriptions, including the coat, highly reliable genus assignments can be obtained.
Comparative investigation into formycin A and pyrazofurin A biosynthesis reveals branch pathways for the construction ofC-nucleoside scaffolds
Authors: Zhang Meng , Zhang Peichao , Xu Gudan , Zhou Wenting , Gao Yaojie , Gong Rong , Cai You-Sheng , Cong Hengjiang , Deng Zixin , Price Neil P. J. , Mao Xiangzhao , Chen Wenqing
Published: August 2019

Formycin A (FOR-A) and pyrazofurin A (PRF-A) are purine-relatedC-nucleoside antibiotics, in which ribose and a pyrazole-derived base are linked by aC-glycosidic bond, however, the logic underlying the biosynthesis of these molecules has remained largely unexplored. Here, we report the discovery of the pathways for FOR-A and PRF-A biosynthesis from diverse actinobacteria, and demonstrate that their biosynthesis is initiated by a lysineN6-monooxygenase. Moreover, we show that theforTandprfE(individually related to FOR-A and PRF-A biosynthesis) mutants are correspondingly capable of accumulating the unexpected pyrazole-related intermediates, compound11and9a. We also decipher the enzymatic basis of ForT/PrfE for theC-glycosidic bond formation in FOR-A/PRF-A biosynthesis. To our knowledge, ForT/PrfE represents the first example of β-RFA-P (β-ribofuranosyl-aminobenzene 5’-phosphate) synthase-like enzymes governingC-nucleoside scaffold construction in natural product biosynthesis. These data establish a foundation for combinatorial biosynthesis of related purine nucleoside antibiotics, and also open the way for target-directed genome mining of PRF-A/FOR-A related antibiotics.

IMPORTANCE

Formycin A (FOR-A) and pyrazofurin A (PRF-A) are well known for their unusual chemical structures and remarkable biological activities. Actually, deciphering FOR-A/PRF-A biosynthesis will not only expand biochemical repertoire for novel enzymatic reactions, but also permit the target-oriented genome mining of FOR-A/PRF-A relatedC-nucleoside antibiotics.
ZGRF1 variants implicated in a sensory reflex epilepsy
Authors: Choudhury Shalini Roy , Satishchandra Parthasarathy , Sinha Sanjib , Anand Anuranjan
Published: August 2019

Hot water epilepsy (HWE) is a sensory reflex epilepsy in which seizures are precipitated by a stimulus such as contact with hot water. While there is a genetic basis to its etiology, identity of the genes underlying this relatively uncommon disorder has remained unknown. Here, we present the results of our studies aimed at identifying a causative gene in a south Indian four-generation family with several affected members. We conducted whole-exome sequencing and examined a known locus that maps to 4q24-q28 (HWE2, MIM: 613340) that we had previously identified. We identified a sequence variant, c.1805C>T (p.Thr602Ile) in ZGRF1, located within the HWE2 locus, co-segregating with the disorder. The transcript structure of ZGRF1 was examined in 288 HWE patients, and five additional missense variants, Arg326Gln, Glu660Gly, Arg1862*, Phe1940Leu and Asp1984Gly, present exclusively or almost exclusively in the patients were found. Functional correlates of the six variants identified were examined in cultured mammalian cells. We observed spindle pole defects during cell division and partially disrupted localization of UPF1, a protein involved in cell cycle regulation, at the spindles. Our observations provide insights into the genetic basis of HWE and suggest the involvement of hitherto unanticipated molecular process in this disorder.
Dramatically diverseS. pombe wtfmeiotic drivers all display high gamete-killing efficiency
Authors: Bravo Núñez María Angélica , Sabbarini Ibrahim M. , Eickbush Michael T. , Liang Yue , Lange Jeffrey J. , Kent Aubrey M. , Zanders Sarah E.
Published: August 2019

Meiotic drivers are selfish genetic loci that force their transmission into more than 50% of the viable gametes made by heterozygotes. Meiotic drivers are known to cause infertility in a diverse range of eukaryotes and are predicted to affect the evolution of genome structure and meiosis. Thewtfgene family ofSchizosaccharomyces pombeincludes both meiotic drivers and drive suppressors and thus offers a tractable model organism to study drive systems. Currently, only a handful ofwtfgenes have been functionally characterized and those genes only partially reflect the diversity of thewtfgene family. In this work, we functionally test 22 additionalwtfgenes. We identify eight new drivers that share between 30-90% amino acid identity with previously characterized drivers. Despite the vast divergence between these genes, they generally drive into >85% gametes when heterozygous. We also find three newwtfgenes that suppress drive, including two that also act as autonomous drivers. Additionally, we find thatwtfgenes do not underlie a weak (64%) transmission bias caused by a locus or loci on chromosome 1. Finally, we find that some Wtf proteins have expression or localization patterns that are distinct from the poison and antidote proteins encoded by drivers and suppressors, suggesting somewtfgenes may have non-meiotic drive functions. Overall, this work expands our understanding of thewtfgene family and the burden selfish driver genes impose onS. pombe.

Article Summary

During gametogenesis, the two gene copies at a given locus, known as alleles, are each transmitted to 50% of the gametes (e.g. sperm). However, some alleles cheat so that they are found in more than the expected 50% of gametes, often at the expense of fertility. This selfish behavior is known as meiotic drive. Some members of thewtfgene family in the fission yeast,Schizosaccharomyces pombe, kill the gametes (spores) that do not inherit them, resulting in meiotic drive favoring thewtfallele. Otherwtfgenes act as suppressors of drive. However, thewtfgene family is diverse and only a small subset of the genes has been characterized. Here we analyze the functions of other members of this gene family and found eight new drivers as well as three new suppressors of drive. Surprisingly, we find that drive is relatively insensitive to changes inwtfgene sequence as highly divergedwtfgenes execute gamete killing with similar efficiency. Finally, we also find that the expression and localization of some Wtf proteins are distinct from those of known drivers and suppressors, suggesting that these proteins may have non-meiotic drive functions.
Identification of biomarkers associated with ovarian cancer based on transcriptome sequencing
Authors: chen jiazhou , peng xiandong , yu min
Published: August 2019

Objective

This study aimed to explore more biomarkers associated with ovarian cancer.

Methods

Cell lines SKOV-3 (ovarian serous carcinoma cells) and MCV152 (benign ovarian epithelial tumor cell) were used in this study and performed transcriptome sequencing. The differentially expressed genes (DEGs) between ovarian cancer cells (SKOV-3) and controls (MCV152) were identified, followed by function enrichment analysis. The expression levels of genes involved in the key pathway were validated through PCR and western blot analyses.

Results

Total 2,020 upregulated and 1,673 downregulated DEGs were obtained between SKOV3 and MCV152 cells. The upregulated and downregulated DEGs were significantly associated with cell adhesion. In addition, the upregulated DEGs were significantly involved in pathways of ECM-receptor interaction, and the downregulated DEGs were involved in PI3K-Akt signaling pathway. PCR and western blot analyses showed that genes (proteins) expression related to PI3K-Akt signaling pathway were in consistent with bioinformatics analysis.

Conclusion

Cell adhesion and extracellular matrix (ECM)-receptor interaction may play an important role in the invasion of ovarian cancer. PI3K-Akt signaling pathway may be involved in the progression of ovarian cancer by up-regulating ANGPT2, FGF18, ITGB4 and ITGB8, and downregulating AKT3 and PIK3AP1.

Highlights

Cell adhesion and ECM-receptor interaction may play important roles in ovarian cancer invasion.

PI3K-Akt signaling pathway may involve in ovarian cancer progression.

ANGPT2, FGF18, ITGB4, ITGB8, AKT3 and PIK3AP1 may serve as biomarkers in ovarian cancer.
Research on software synchronization method of real-time ethernet distributed motion control system
Authors: Huang Zhengyu , Chen Lingyu , Zhang Lianchao , Fan Shixun , Fan Dapeng
Published: August 2019

Purpose

This paper aims to analyze the key factors influencing the synchronization performance of distributed motion control system and to improve the synchronization performance for peripherals control of this system.

Design/methodology/approach

This paper deals with the software synchronization problems of distributed motion control system based on real-time Ethernet. First, combined with communication and control tasks, the key factors affecting synchronization performance of system are analyzed. Then, aiming at key factors and considering the synchronization of system bus, protocol conversion and task scheduling, a software synchronization method based on CANopen protocol and real-time Ethernet is proposed. Finally, the feasibility of this method is verified by establishing distributed motion control system and testing the synchronization performance of terminal control signals of slaves.

Findings

Based on this method, the results show that the synchronization accuracy for peripherals control of all slaves could be about 100 ns.

Practical implications

This research provides high-precision synchronization method, which could lay a foundation for the application of distributed motion control system in the field of assembly automation, such as multi-axis assembly robots control.

Originality/value

In distributed motion control system, many factors affect the synchronization performance. At present, there is no synchronization method that could comprehensively consider these factors. This paper not only analyzes the key factors influencing the synchronization performance of system but also proposes a synchronization method. Therefore, the method proposed in this paper has certain theoretical value and engineering significance.
A novel PGSA–PSO hybrid algorithm for structural optimization
Authors: Jiang Zhengrong , Lin Quanpan , Shi Kairong , Pan Wenzhi
Published: August 2019

Purpose

The purpose of this paper is to propose a new hybrid algorithm, named improved plant growth simulation algorithm and particle swarm optimization hybrid algorithm (PGSA–PSO hybrid algorithm), for solving structural optimization problems.

Design/methodology/approach

To further enhance the optimization efficiency and precision of this algorithm, the optimization solution process of PGSA–PSO comprises two steps. First, an excellent initial growth point is selected by PSO. Then, the global optimal solution can be obtained quickly by PGSA and its improved strategy called growth space adjustment strategy. A typical mathematical example is provided to verify the capacity of the new hybrid algorithm to effectively improve the global search capability and search efficiency of PGSA. Moreover, PGSA–PSO is applied to the optimization design of a suspended dome structure.

Findings

Through typical mathematical example, the improved strategy can improve the optimization efficiency of PGSA considerably, and an initial growth point that falls near the global optimal solution can be obtained. Through the optimization of the pre-stress of a suspended dome structure, compared with other methods, the hybrid algorithm is effective and feasible in structural optimization.

Originality/value

Through the examples of suspended dome structure, it shows that the optimization efficiency and precision of PGSA–PSO are better than those of other algorithms and methods. PGSA–PSO is effective and feasible in structural optimization problems such as pre-stress optimization, size optimization, shape optimization and even topology optimization.
Non-invasive implementation of nonlinear isogeometric analysis in an industrial FE software
Authors: Tirvaudey Marie , Bouclier Robin , Passieux Jean-Charles , Chamoin Ludovic
Published: August 2019

Purpose

The purpose of this paper is to further simplify the use of NURBS in industrial environnements. Although isogeometric analysis (IGA) has been the object of intensive studies over the past decade, its massive deployment in industrial analysis still appears quite marginal. This is partly due to its implementation, which is not straightforward with respect to the elementary structure of finite element (FE) codes. This often discourages industrial engineers from adopting isogeometric capabilities in their well-established simulation environment.

Design/methodology/approach

Based on the concept of Bézier and Lagrange extractions, a novel method is proposed to implement IGA from an existing industrial FE code with the aim of bringing human implementation effort to the minimal possible level (only using standard input-output of finite element analysis (FEA) codes, avoid code-dependent subroutines implementation). An approximate global link to go from Lagrange polynomials to non-uniform-rational-B-splines functions is formulated, which enables the whole FE routines to be untouched during the implementation.

Findings

As a result, only the linear system resolution step is bypassed: the resolution is performed in an external script after projecting the FE system onto the reduced, more regular and isogeometric basis. The novel procedure is successfully validated through different numerical experiments involving linear and nonlinear isogeometric analyses using the standard input/output of the industrial FE software Code_Aster.

Originality/value

A non-invasive implementation of IGA into FEA software is proposed. The whole FE routines are untouched during the novel implementation procedure; a focus is made on the IGA solution of nonlinear problems from existing FEA software; technical details on the approach are provided by means of illustrative examples and step-by-step implementation; the methodology is evaluated on a range of two- and three-dimensional elasticity and elastoplasticity benchmarks solved using the commercial software Code_Aster.
A domain-specific measure of centrality for water distribution networks
Authors: Zarghami Seyed Ashkan , Gunawan Indra
Published: August 2019

Purpose

In recent years, centrality measures have been extensively used to analyze real-world complex networks. Water distribution networks (WDNs), as a good example of complex networks, exhibit properties not shared by other networks. This raises concerns about the effectiveness of applying the classical centrality measures to these networks. The purpose of this paper is to generate a new centrality measure in order to stick more closely to WDNs features.

Design/methodology/approach

This work refines the traditional betweenness centrality by adding a hydraulic-based weighting factor in order to improve its fit with the WDNs features. Rather than an exclusive focus on the network topology, as does the betweenness centrality, the new centrality measure reflects the importance of each node by taking into account its topological location, its demand value and the demand distribution of other nodes in the network.

Findings

Comparative analysis proves that the new centrality measure yields information that cannot be captured by closeness, betweenness and eigenvector centrality and is more accurate at ranking the importance of the nodes in WDNs.

Practical implications

The following practical implications emerge from the centrality analysis proposed in this work. First, the maintenance strategy driven by the new centrality analysis enables practitioners to prioritize the components in the network based on the priority ranking attributed to each node. This allows for least cost decisions to be made for implementing the preventive maintenance strategies. Second, the output of the centrality analysis proposed herein assists water utilities in identifying the effects of components failure on the network performance, which in turn can support the design and deployment of an effective risk management strategy.

Originality/value

The new centrality measure, proposed herein, is distinct from the conventional centrality measures. In contrast to the classical centrality metrics in which the importance of components is assessed based on a pure topological viewpoint, the proposed centrality measure integrates both topological and hydraulic attributes of WDNs and therefore is more accurate at ranking the importance of the nodes.
Mediating effects of perceived environment support and knowledge sharing between self-efficacy and job performance of SME employees
Authors: Na-Nan Khahan , Saribut Salitta , Sanamthong Ekkasit
Published: August 2019

Purpose

Currently, small and medium-sized enterprises (SMEs) concentrate on developing their employees’ potential to ensure high job performance. Enhancing the perception of efficacy is important to encourage employees to perform their responsibilities with increased self-confidence. Perceived environmental support and knowledge sharing are also significant factors that boost employees’ potential to achieve targets. The purpose of this paper is to examine how self-efficacy (SE) relates both directly and indirectly to employee job performance through perceived environmental support and knowledge sharing.

Design/methodology/approach

Empirical data were garnered from a sample of 344 admins working at SMEs in Central Thailand and structural equation modelling was used to test the proposed relationships.

Findings

SE had a strong positive influence on employee job performance, perceived environmental support and knowledge sharing, while perceived environmental support and knowledge sharing positively influenced employee job performance. Perceived environmental support and knowledge sharing were considered to be partial mediating factors of SE in the employee job performance model.

Originality/value

This research extends understanding of the relationship between SE and employee job performance. The findings shed light on mediating roles of perceived environmental support and knowledge sharing regarding the relationship between SE and employee job performance.
Assessment of factors affecting maintenance cost of public school facilities
Authors: Hassanain Mohammad A. , Al-Zahrani Mohammad , Abdallah Abdullatif , Sayed Ahmed M.Z.
Published: August 2019

Purpose

The purpose of this paper is to identify and assess the significance of various factors affecting maintenance costs of public school facilities.

Design/methodology/approach

Detailed literature review resulted in identifying 54 factors that were categorized under nine groups. This was followed by a questionnaire survey completed by 60 experienced professionals. The relative importance index was used to determine the in-group ranking, as well as the overall ranking of these factors.

Findings

The study established that the five most significant factors affecting the maintenance cost of public school facilities were “not providing operations and maintenance manuals to maintenance group” in the “construction phase” category, “ignoring maintainability studies in design” in the “design phase” category, “specification of low-quality materials” in the “design phase” category, “selection criteria of contractors” in the “regulations and contracting” category, and “lack of quality control during work execution” in the “construction phase” category.

Originality/value

The present research represents the first research covering the maintenance cost of public school facilities in Saudi Arabia. The study also presents the unique landscape of facility maintenance in the Saudi Arabian context. The outcome of this research has the potential to significantly cut down unnecessary costs rooted in expensive maintenance of public school facilities, enhancing the quality of these facilities. The findings also underscore the necessity of collaboration and coordination of the various key disciplines toward the realization of cost-effective school facilities.
Micro-level sectoral analysis of developing economies
Authors: Muhtaseb Hind , Khoury Grace , Tovstiga George
Published: August 2019

Purpose

The purpose of this paper is to examine current performance management practices, identify potential areas of improvement and recommend appropriate interventions. Developing economies continue to intrigue in light of the promise they hold for future growth markets. Existing studies tend to focus on macro-economic factors and to concentrate on a few regions. Few studies have looked at the lesser developed Middle-Eastern regions, such as Palestine. This study seeks to address that deficit; it examines firm-level factors relevant to the competitive performance of enterprises in the Palestinian stone and marble industry, one of the most important industries in the region.

Design/methodology/approach

The study utilizes a mixed-methods exploratory qualitative and quantitative approach that probes operational and strategic performance factors. Interviews and insights derived from a survey-based research data from 45 respondents representing a sampling of 36 enterprises form the basis of the analysis.

Findings

Findings suggest that the majority of performance measures employed by the firms investigated rely primarily on traditional financial indicators. Although some progressive metrics including those targeting measures of productivity and process efficiency are being adopted by firms in the sector, measures that focus on long-term strategic growth promoters such as innovation and organizational learning are largely not yet employed.

Originality/value

The paper concludes with recommendations for how firms competing in such environments might enhance and improve their performance management.
Cultural influences moderating learners’ adoption of serious 3D games for managerial learning
Authors: Siala Haytham , Kutsch Elmar , Jagger Suzy
Published: August 2019

Purpose

The purpose of this paper is to investigate whether learners from different cultures adopt a serious 3D game to facilitate the learning of transferable managerial skills (ethics) and knowledge.

Design/methodology/approach

A cross-sectional, cross-country survey study (n=319) was conducted recruiting participants from one North American and two British universities. The survey data and the conceptual model have been analysed and tested using confirmatory factor analysis and structural equation modelling.

Findings

Participants displayed positive attitudes towards the 3D game and responded positively to theory presented as “real-life” scenarios; gamification techniques such as interactions and dialogue, and rewards and progression levels, which are part of the game, albeit the participants’ adoption was driven more by extrinsic motivations (rewards) than intrinsic ones (ease of use and entertainment). In addition, the empirical results suggest that when gender is taken into account, the perceptions and needs of cross-cultural learners in serious gaming environments vary and display characteristics that are similar to Rogers’ five adopter categories; thus, culture could significantly shape learners’ decisions to adopt a serious game as a managerial learning tool.

Research limitations/implications

For future researchers, this paper highlights various levels of training, support and promotional awareness that need to be considered to facilitate the adoption of serious games for managerial learning.

Practical implications

For academics and practitioners in work-based learning and managerial training environments, this paper highlights the salient factors that need to be inherent in a serious 3D game, and best practices for scaffolding existing instructional approaches or training interventions.

Originality/value

In light of Rogers’ five adopter categories, this cross-country study involving culturally diverse learners provides key insight into the potential application of serious games as a practice-based learning instrument in academia and industry.
Growth enterprise market in Hong Kong
Authors: Nguyen Trang , Chaiechi Taha , Eagle Lynne , Low David
Published: August 2019

Purpose

Growth enterprise market (GEM) in Hong Kong is acknowledged as one of the world’s most successful examples of small and medium enterprise (SME) stock market. The purpose of this paper is to examine the evolving efficiency and dual long memory in the GEM. This paper also explores the joint impacts of thin trading, structural breaks and inflation on the dual long memory.

Design/methodology/approach

State-space GARCH-M model, Kalman filter estimation, factor-adjustment techniques and fractionally integrated models: ARFIMA–FIGARCH, ARFIMA–FIAPARCH and ARFIMA–HYGARCH are adopted for the empirical analysis.

Findings

The results indicate that the GEM is still weak-form inefficient but shows a tendency towards efficiency over time except during the global financial crisis. There also exists a stationary long-memory property in the market return and volatility; however, these long-memory properties weaken in magnitude and/or statistical significance when the joint impacts of the three aforementioned factors were taken into account.

Research limitations/implications

A forecasts of the hedging model that capture dual long memory could provide investors further insights into risk management of investments in the GEM.

Practical implications

The findings of this study are relevant to market authorities in improving the GEM market efficiency and investors in modelling hedging strategies for the GEM.

Originality/value

This study is the first to investigate the evolving efficiency and dual long memory in an SME stock market, and the joint impacts of thin trading, structural breaks and inflation on the dual long memory.
Improving continuity of forensic mental health care
Authors: de Vogel Vivienne , Schaftenaar Petra , Clercx Maartje
Published: August 2019

Purpose

Continuity of forensic mental health care is important in building protective structures around a patient and has been shown to decrease risks of relapse. Realising continuity can be complicated due to restrictions from finances or legislation and difficulties in collaboration between settings. In the Netherlands, several programs have been developed to improve continuity of forensic care. It is unknown whether professionals and clients are sufficiently aware of these programs. The paper aims to discuss this issue.

Design/methodology/approach

The experienced difficulties and needs of professionals and patients regarding continuity of forensic care were explored by means of an online survey and focus groups. The survey was completed by 318 professionals. Two focus groups with professionals (15 participants), one focus group and one interview with patients (six participants) were conducted.

Findings

The overall majority (85.6 percent) reported to experience problems in continuity on a frequent basis. The three main problems are: first, limited capacity for discharge from inpatient to outpatient or sheltered living; second, collaboration between forensic and regular mental health care; and, third, limited capacity for long-term inpatient care. Only a quarter of the participants knew the existing programs. Actual implementation of these programs was even lower (3.9 percent). The top three of professionals’ needs are: better collaboration; higher capacity; more knowledge about rules and regulation. Participants of the focus groups emphasized the importance of transparent communication, timely discharge planning and education.

Practical implications

Gathering best practices about regional collaboration networks and developing a blueprint based on the best practices could be helpful in improving collaboration between setting in the forensic field. In addition, more use of systematic discharge planning is needed to improve continuity in forensic mental health care. It is important to communicate in an honest, transparent way to clients about their forensic mental health trajectories, even if there are setbacks or delays. More emphasis needs to be placed on communicating and implementing policy programs in daily practice and more education about legislation is needed Structured evaluations of programs aiming to improve continuity of forensic mental health care are highly needed.

Originality/value

Policy programs hardly reach professionals. Professionals see improvements in collaboration as top priority. Patients emphasize the human approach and transparent communication.
Religion, spirituality and personal recovery among forensic patients
Authors: Glorney Emily , Raymont Sophie , Lawson Amy , Allen Jessica
Published: August 2019

Purpose

Religion and spirituality are well-researched concepts within the field of psychology and mental health yet they have rarely been researched in high-secure services within the UK. Research in mental health and prison contexts suggests benefits of religion/spirituality to coping, social support, self-worth, symptoms of depression and anxiety and behavioural infractions. The purpose of this paper is to investigate the role of religion/spirituality in high-secure service users’ personal recovery.

Design/methodology/approach

Semi-structured interviews were carried out with 13 male patients in a high-secure hospital, with primary diagnoses of mental illness (n=11) or personality disorder (n=2). Participants were from a range of religious/spiritual backgrounds and were asked about how their beliefs impact their recovery and care pathways within the hospital. Data were analysed using interpretative phenomenological analysis.

Findings

Three superordinate themes were identified: “religion and spirituality as providing a framework for recovery”; “religion and spirituality as offering key ingredients in the recovery process”; and “barriers to recovery through religion/spirituality”. The first two themes highlight some of the positive aspects that aid participants’ recovery. The third theme reported hindrances in participants’ religious/spiritual practices and beliefs. Each theme is discussed with reference to sub-themes and illustrative excerpts.

Practical implications

Religion/spirituality might support therapeutic engagement for some service users and staff could be more active in their enquiry of the value that patients place on the personal meaning of this for their life.

Originality/value

For the participants in this study, religion/spirituality supported the principles of recovery, in having an identity separate from illness or offender, promoting hope, agency and personal meaning.