bluuebunny/crossref_metadata_2025 huggingface dataset:
Paralytic, theDrosophilavoltage-gated sodium channel, regulates proliferation of neural progenitors
Authors: Piggott Beverly J. , Peters Christian J. , He Ye , Huang Xi , Younger Susan , Jan Lily Yeh , Jan Yuh Nung
Published: October 2019

Proliferating cells, typically considered “non-excitable,” nevertheless exhibit regulation by bioelectrical signals. Notably, voltage-gated sodium channels (VGSC) that are crucial for neuronal excitability, are also found in progenitors and upregulated in cancer. Here, we identify a role for VGSC in proliferation ofDrosophilaneuroblast (NB) lineages within the central nervous system. Loss ofparalytic (para), the sole gene that encodesDrosophilaVGSC, reduces neuroblast progeny cell number. The type II neuroblast lineages, featuring a transit-amplifying intermediate neural progenitors (INP) population similar to that found in the developing human cortex, are particularly sensitive toparamanipulation. Following a series of asymmetric divisions, INPs normally exit the cell cycle through a final symmetric division. Our data suggests that loss ofparainduces apoptosis in this population, whereas overexpression leads to an increase in INPs and overall neuroblast progeny cell numbers. These effects are cell autonomous and depend on Para channel activity. Reduction of Para not only affects normal NB development, but also strongly suppresses brain tumor mass, implicating a role for Para in cancer progression. To our knowledge, our studies are the first to identify a role for VGSC in neural progenitor proliferation. Elucidating the contribution of VGSC in proliferation will advance our understanding of bioelectric signaling within development and disease states.
A Chemoenzymatic Method for Glycoproteomic N-glycan Type Quantitation
Authors: Li Henghui , Li Leyuan , Cheng Kai , Ning Zhibin , Mayne Janice , Zhang Xu , Walker Krystal , Chen Rui , Twine Susan , Li Jianjun , Figeys Daniel
Published: October 2019

Glycosylation is one of the most important post-translational modifications in biological systems. Current glycoproteome methods mainly focus on qualitative identification of glycosylation sites or intact glycopeptides. However, the systematic quantitation of glycoproteins has remained largely unexplored. Here, we developed a chemoenzymatic method to quantitatively investigate N-glycoproteome based on the N-glycan types. Taking advantage of the specificity of different endoglycosidases and isotope dimethyl labeling, six N-glycan types of structures linked on each glycopeptide, including high-mannose/hybrid, bi-antennary and tri-antennary with/without core fucose, were quantified. As a proof of principle, the glycoproteomic N-glycan type quantitative (glyco-TQ) method was first used to determine the N-glycan type composition of immunoglobulin G1 (IgG1) Fc fragment. Then we applied the method to analyze the glycan type profile of proteins in the breast cancer cell line MCF7, and quantitatively revealed the N-glycan type micro-heterogeneity at both the glycopeptide and glycoprotein levels. The novel quantitative strategy to evaluate the relative intensity of the six states of N-glycan type glycosylation on each site provides a new avenue to investigate function of glycoproteins in broad areas, such as cancer biomarker research, pharmaceuticals characterization and anti-glycan vaccine development.
Probing the neural dynamics of mnemonic representations after the initial consolidation
Authors: Liu Wei , Kohn Nils , Fernández Guillén
Published: October 2019

Memories are not stored as static engrams, but as dynamic representations affected by processes occurring after initial encoding. Previous studies revealed changes in activity and mnemonic representations in visual processing areas, parietal lobe, and hippocampus underlying repeated retrieval and suppression. However, these neural changes are usually induced by memory modulation immediately after memory formation. Here, we investigated 27 healthy participants with a two-day functional Magnetic Resonance Imaging design to probe how established memories are dynamically modulated by retrieval and suppression 24 hours after learning. Behaviorally, we demonstrated that established memories can still be strengthened by repeated retrieval. By contrast, repeated suppression had a modest negative effect, and suppression-induced forgetting was associated with individual suppression efficacy. Neurally, we demonstrated item-specific pattern reinstatements in visual processing areas, parietal lobe, and hippocampus. Then, we showed that repeated retrieval reduced activity amplitude in the ventral visual cortex and hippocampus, but enhanced the distinctiveness of activity patterns in the ventral visual cortex and parietal lobe. Critically, reduced activity was associated with enhanced representation of idiosyncratic memory traces in ventral visual cortex and precuneus. In contrast, repeated memory suppression was associated with the reduced lateral prefrontal activity, but relative intact mnemonic representations. Our results replicated most of the neural changes induced by memory retrieval and suppression immediately after learning and extended those findings to established memories after initial consolidation. Active retrieval seems to promote episode-unique mnemonic representations in the neocortex after initial encoding but also consolidation.

Highlights

Repeated retrieval strengthened consolidated memories, while repeated suppression had a modest negative effect.

Pattern reinstatements of individual memories were detected in the visual area, parietal lobe, and hippocampus after 24 hours.

After repeated retrieval, reduced activity amplitude was associated with increased distinctiveness of activity patterns in the ventral visual cortex and right precuneus.

Repeated suppression was associated with the reduced lateral prefrontal activity, but unchanged mnemonic representations.
Monitoring the prolonged TNF stimulation in space and time with topological-functional networks
Authors: Papoudas Stylianos Mavropoulos , Papanikolaou Nikolaos , Nikolaou Christoforos
Published: October 2019

Genes in linear proximity often share regulatory inputs, expression and evolutionary patterns, even in complex eukaryote genomes with extensive intergenic sequences. Gene regulation, on the other hand, is effected through the co-ordinated activation (or suppression) of genes participating in common biological pathways, which are often transcribed from distant loci. Existing approaches for the study of gene expression focus on the functional aspect, taking positional constraints into account only marginally.

In this work we propose a novel concept for the study of gene expression, through the combination of topological and functional information into bipartite networks. Starting from genome-wide expression profiles, we define extended chromosomal regions with consistent patterns of differential gene expression and then associate these domains with enriched functional pathways. By analyzing the resulting networks in terms of size, connectivity and modularity we can draw conclusions on the way genome organization may underlie the gene regulation program.

We implement our approach in a detailed RNASeq profiling of sustained TNF stimulation of mouse synovial fibroblasts. Bipartite network analysis suggests that the cytokine response set by TNF, progresses through two distinct transitions. An early generalization of the inflammatory response, marked by an increase in related functions and high connectivity of corresponding genomic loci, that is followed by a late shutdown of immune functions and the redistribution of expression to developmental and cell adhesion pathways and distinct chromosomal regions.

Our results suggest that the incorporation of topological information may provide additional insights in the underlying topological constraints that are shaping gene expression.
Cell cycle-dependent active stress drives epithelia remodeling
Authors: Devany John , Sussman Daniel M. , Yamamoto Takaki , Manning M. Lisa , Gardel Margaret L.
Published: October 2019

Epithelia have distinct cellular architectures, which are established in development, re-established after wounding, and maintained during tissue homeostasis despite cell turnover and mechanical perturbations. In turn, cell shape also controls tissue function as a regulator of cell differentiation, proliferation, and motility. Here we investigate cell shape changes in a model epithelial monolayer. After the onset of confluence, cells continue to proliferate and change shape over time, eventually leading to a final architecture characterized by arrested motion and more regular cell shapes. Such monolayer remodeling is robust, with qualitatively similar evolution in cell shape and dynamics observed across disparate perturbations. Here we quantify differences in monolayer remodeling guided by the active vertex model to identify underlying order parameters controlling epithelial architecture. When monolayers are formed atop extracellular matrix with varied stiffness, we find the cell density at which motion arrests varies significantly but the cell shape remains constant, consistent with the onset of tissue rigidity. In contrast, pharmacological perturbations can significantly alter the cell shape at which tissue dynamics is arrested, consistent with varied amounts of active stress within the tissue. Across all experimental conditions the final cell shape is well correlated to the cell proliferation rate, and cell cycle inhibition immediately arrests cell motility. Finally, we demonstrate cell-cycle variation in junctional tension as a source of active stress within the monolayer. Thus, the architecture and mechanics of epithelial tissue can arise from an interplay between cell mechanics and stresses arising from cell cycle dynamics.

SIGNIFICANCE STATEMENT

The morphology of biological tissue is determined by the shape and density of constituent cells. Here we measure the dynamics of cells in model epithelial tissues to study the evolution of their shape and density over time. Guided by a mathematical model, we find that cell shape is controlled by rigidity and active stresses within the tissue. We then show that cell cycle dynamics are the source of active stress that drives epithelial remodeling.
Net effects of field and landscape scale habitat on insect and bird damage to sunflowers
Authors: Kross Sara M. , Martinico Breanna L. , Bourbour Ryan P. , Townsend Jason M. , McColl Chris , Kelsey T. Rodd
Published: October 2019

Agriculture-dominated landscapes harbor significantly diminished biodiversity, but are also areas in which significant gains in biodiversity can be achieved. Planting or retaining woody vegetation along field margins can provide farmers with valuable ecosystem services while simultaneously benefitting biodiversity. However, when crops are damaged by the biodiversity harbored in such vegetation, farmers are reluctant to incorporate field margin habitat onto their land and may even actively remove such habitats, at cost to both farmers and non-target wildlife. We investigated how damage by both insect pests (sunflower moth,Homoeosoma electellum) and avian pests to sunflower (Helianthus annuus) seed crops varied as a function of bird abundance and diversity, as well as by landscape-scale habitat. Surveys for insect damage, avian abundance, and bird damage were carried out over two years in 30 different fields on farms in California’s Sacramento Valley. The mean percentage of moth-damaged sunflowers sampled was nearly four times higher in fields that had bare or weedy margins (23.5%) compared to fields with woody vegetation (5.9%) and decreased in both field types as landscape-scale habitat complexity declined. Birds damaged significantly fewer sunflower seeds (2.7%) than insects, and bird damage was not affected by field margin habitat type, landscape-scale habitat variables, or avian abundance, but was significantly higher along field edges compared to ≥ 50m from the field edge. Avian species richness nearly doubled in fields with woody margin habitat compared to fields with bare/weedy margins in both the breeding season and in fall. These results indicate that the benefits of planting or retaining woody vegetation along sunflower field margins could outweigh the ecosystem disservices related to bird damage, while simultaneously increasing the biodiversity value of intensively farmed agricultural landscapes.
A thalamic reticular circuit for head direction cell tuning and spatial navigation
Authors: Vantomme Gil , Rovó Zita , Cardis Romain , Béard Elidie , Katsioudi Georgia , Guadagno Angelo , Perrenoud Virginie , Fernandez Laura MJ , Lüthi Anita
Published: October 2019

To navigate in space, an animal must refer to sensory cues to orient and move. Circuit and synaptic mechanisms that integrate cues with internal head-direction (HD) signals remain, however, unclear. We identify an excitatory synaptic projection from the presubiculum (PreS) and the multisensory-associative retrosplenial cortex (RSC) to the anterodorsal thalamic reticular nucleus (TRN), so far classically implied in gating sensory information flow. In vitro, projections to TRN involved AMPA/NMDA-type glutamate receptors that initiated TRN cell burst discharge and feedforward inhibition of anterior thalamic nuclei. In vivo, chemogenetic anterodorsal TRN inhibition modulated PreS/RSC-induced anterior thalamic firing dynamics, broadened the tuning of thalamic HD cells, and led to preferential use of allo-over egocentric search strategies in the Morris water maze. TRN-dependent thalamic inhibition is thus an integral part of limbic navigational circuits wherein it coordinates external sensory and internal HD signals to regulate the choice of search strategies during spatial navigation.
OdoBD: An online database for the dragonflies and damselflies of Bangladesh
Authors: Shah Md Nur Ahad , Khan Md Kawsar
Published: October 2019

Combining scientific data over a long-time period is necessary to understand the diversity, population trends, and conservation importance of any taxa in a global and regional scale. Bangladesh is located in a biodiversity hotspot region, however, till date, only few animal groups has been extensively investigated at a nation-wide scale. Although being one of the earliest and well-known insect groups, the knowledge on Odonata of this region remains rudimentary and dispersed. To resolve this issue, we have developed an online database for the Odonata of Bangladesh. We have compiled data from our last four years field study, from previously published research articles, field guides, and also collected data from citizen scientists regarding Bangladeshi odonates. Odonata of Bangladesh database (http://www.odobd.org) contains information on morphology, abundance, gene and protein sequences, local and global distribution and conservation status of the Odonata of Bangladesh. The database also demonstrates gender specified photographs with descriptions for better understanding for the novice researchers and naturalists. Odonata of Bangladesh database provides a comprehensive source for meta-analyses in ecology, conservation biology, and genetic research.
GAIA: an integrated metagenomics suite
Authors: Paytuví A. , Battista E. , Scippacercola F. , Aiese Cigliano R. , Sanseverino W.
Published: October 2019

Identifying the biological diversity of a microbial population is of fundamental importance due to its implications in industrial processes, environmental studies and clinical applications. Today, there is still an outstanding need to develop new, easy-to-use bioinformatics tools to analyze both amplicon and shotgun metagenomics, including both prokaryotic and eukaryotic organisms, with the highest accuracy and the lowest running time. With the aim of overcoming this need, we introduce GAIA, an online software solution that has been designed to provide users with the maximum information whether it be 16S, 18S, ITS, or shotgun analysis. GAIA is able to obtain a comprehensive and detailed overview at any taxonomic level of microbiomes of different origins: human (e.g. stomach or skin), agricultural and environmental (e.g. land, water or organic waste). By using recently published benchmark datasets from shotgun and 16S experiments we compared GAIA against several available pipelines. Our results show that for shotgun metagenomics, GAIA obtained the highest F-measures at species level above all tested pipelines (CLARK, Kraken, LMAT, BlastMegan, DiamondMegan and NBC). For 16S metagenomics, GAIA also obtained excellent F-measures comparable to QIIME at family level. The overall objective of GAIA is to provide both the academic and industrial sectors with an integrated metagenomics suite that will allow to perform metagenomics data analysis easily, quickly and affordably with the highest accuracy.
Identification of a small molecule that stimulates human β-cell proliferation and insulin secretion, and protects against cytotoxic stress in rat insulinoma cells
Authors: Hohmeier Hans E. , Zhang Lu , Taylor Brandon , Stephens Samuel , McNamara Peter , Laffitte Bryan , Newgard Christopher B.
Published: October 2019

A key event in the development of both major forms of diabetes is the loss of functional pancreatic islet β-cell mass. Strategies aimed at enhancing β-cell regeneration have long been pursued, but methods for reliably inducing human β-cell proliferation with full retention of key functions such as glucose-stimulated insulin secretion (GSIS) are still very limited. We have previously reported that overexpression of the homeobox transcription factor Nkx6.1 stimulates β-cell proliferation, while also enhancing GSIS and providing protection against β-cell cytotoxicity through induction of the VGF prohormone. We developed an Nkx6.1 pathway screen by stably transfecting 832/13 rat insulinoma cells with a VGF promoter-luciferase reporter construct, using the resultant cell line to screen a 630,000 compound chemical library. We isolated three compounds with consistent effects to stimulate human islet cell proliferation. Further studies of the most potent of these compounds, GNF-9228, revealed that it selectively activates human β-cell relative to α-cell proliferation and has no effect on δ-cell replication. In addition, pre-treatment, but not short term exposure of human islets to GNF-9228 enhances GSIS. GNF-9228 also protects 832/13 insulinoma cells against ER stress- and inflammatory cytokine-induced cytotoxicity. In contrast to recently emergent Dyrk1a inhibitors that stimulate human islet cell proliferation, GNF-9228 does not activate NFAT translocation. These studies have led to identification of a small molecule with pleiotropic positive effects on islet biology, including stimulation of human β-cell proliferation and insulin secretion, and protection against multiple agents of cytotoxic stress.
Bees support farming. Does farming support bees?
Authors: Virkar Preeti S. , Siddhu Ekta , Uniyal V. P.
Published: October 2019

Tropical regions are subjected to rapid land use changes altering species composition and diversity in communities. The non-Apisbees are vital invertebrates continued to be highly neglected in the tropics. We compared their diversity status, richness and composition across natural areas and agroecosystems in Doon valley, a subtropical-temperate landscape situated at the foothills of outer Himalayas in India. We investigated how two major habitats relate to non-Apisbee diversity, specifically seeking answers to (1) Whether natural habitat is a refuge to richer and rarer bee communities than agroecosystems? (2) Are natural habitats important for supporting wild bee populations in agroecosystems? (3) Do polyculture farms behave similar to natural habitats and therefore support richer bee communities than monoculture? Observation and pantrap sampling were used to collect data. We recorded 43 species belonging to bees of five families. The findings of our investigation demonstrate the importance of natural habitats as a potential refuge for non-Apisbees. The findings highlighted that Doon valley harboured twenty-five rare species of non-Apisbees, and natural habitats are a refuge to 11 rare specialist species (clamtest; Specialization threshold K = 2/3, Alpha level = 0.005). Natural habitat diversity in Doon valley supports bee communities in nearby agroecosystems (R2 = 0.782, SE = 0.148, P = 0.004). Polyculture practices in agroecosystems (<100m from forest H’ = 2.15; >100m from forest = 2.08) in the valley mimic natural habitats (H’ = 2.37) and support diverse non-Apisbee communities (2.08) in comparison to monocultures (<100m from forest H’ = 2.13; >100m from forest =1.56). Bees evolved with flowering plants over 120 million years and they suffice an ever-growing anthropogenic nutrition needs with their services through enhanced agricultural production in pursuit of forage. We finally recommend similar assessments of bee diversity and plants they support in different habitats and vice versa.
A computational approach for mapping heme biology in the context of hemolytic disorders
Authors: Humayun Farah , Domingo-Fernández Daniel , George Ajay Abisheck Paul , Hopp Marie-Thérèse , Syllwasschy Benjamin F. , Detzel Milena S. , Hoyt Charles Tapley , Hofmann-Apitius Martin , Imhof Diana
Published: October 2019

Heme is an iron ion-containing molecule found within hemoproteins such as hemoglobin and cytochromes that participates in diverse biological processes. While its unlimited supply has been implicated in deleterious processes in several diseases including malaria, sepsis, ischemia-reperfusion, and disseminated intravascular coagulation, little is known about its regulatory and signaling functions. A majority of the computational research to elucidate these functions has been purely data-driven due to the absence of curated pathway resources, which have proven useful in the computational study in other indications. Here, we present two resources aimed to exploit this unexplored information to model heme biology. The first resource is an ontology covering heme-specific terms not yet included in standard controlled vocabularies. Using this ontology, we curated and modeled a corpus of 46 scientific articles to generate a mechanistic knowledge graph representing the heme’s interactome for that particular literature. Finally, we demonstrated the utility of these resources by investigating the role of heme in the Toll-like receptor signaling pathway. Our analysis proposed a series of crosstalk events that could explain the role of heme in activating the TLR4 signaling pathway. In summary, the presented work opens the door for the scientific community to explore in more detail the published knowledge on heme biology.
Predicting agronomic traits and associated genomic regions in diverse rice landraces using marker stability
Authors: Orhobor Oghenejokpeme I. , Alexandrov Nickolai N. , Chebotarov Dmytro , Kretzschmar Tobias , McNally Kenneth L. , Sanciangco Millicent D. , King Ross D.
Published: October 2019

To secure the world’s food supply it is essential that we improve our knowledge of the genetic underpinnings of complex agronomic traits. In this paper, we report our findings from performing trait prediction and association mapping using marker stability in diverse rice landraces. We used the least absolute shrinkage and selection operator as our marker selection algorithm, and considered twelve real agronomic traits and a hundred simulated traits using a population with approximately a hundred thousand markers. For trait prediction, we considered several statistical/machine learning methods. We found that some of the methods considered performed best when preselected markers using marker stability were used. However, our results also show that one might need to make a trade-off between model size and performance for some learning methods. For association mapping, we compared marker stability to the genome-wide efficient mixed-model analysis (GEMMA), and for the simulated traits, we found that marker stability significantly outperforms GEMMA. For the real traits, marker stability successfully identifies multiple associated markers, which often entail those selected by GEMMA. Further analysis of the markers selected for the real traits using marker stability showed that they are located in known quantitative trait loci (QTL) using the QTL Annotation Rice Online database. Furthermore, co-functional network prediction of the selected markers using RiceNet v2 also showed association to known controlling genes. We argue that a wide adoption of the marker stability approach for the prediction of agronomic traits and association mapping could improve global rice breeding efforts.
CrispRdesignR: A Versatile Guide RNA Design Package in R for CRISPR/Cas9 Applications
Authors: Beeber Dylan , Chain Frédéric JJ
Published: October 2019

The success of CRISPR/Cas9 gene editing applications relies on the efficiency of the single guide RNA (sgRNA) used in conjunction with the Cas9 protein. Current sgRNA design software vary in the details they provide on sgRNA sequence efficiency and are almost exclusively restricted to model organisms. The crispRdesignR package aims to address these limitations by providing comprehensive sequence features of the generated sgRNAs in a single program, which allows users to predict sgRNA efficiency and design sgRNA sequences for systems that currently do not have optimized efficiency scoring methods. crispRdesignR reports extensive information on all designed sgRNA sequences with robust off-target calling and annotation and can be run in a user-friendly graphical interface. The crispRdesignR package is implemented in R and has fully editable code for specialized purposes including sgRNA design in user-provided genomes. The package is platform independent and extendable, with its source code and documentation freely available at https://github.com/dylanbeeber/crispRdesignR.
Variant calling using NGS and sequence capture data for population and evolutionary genomic inferences in Norway Spruce (Picea abies)
Authors: Bernhardsson Carolina , Wang Xi , Eklöf Helena , Ingvarsson Pär K.
Published: October 2019

Advances in next-generation sequencing methods and the development of new statistical and computational methods have opened up possibilities made for large-scale, high quality genotyping in most organisms. Conifer genomes are large and are known to contain a high fraction of repetitive elements and this complex genome structure has bearings for approaches that aim to use next-generation sequencing methods for genotyping. In this chapter we provide a detailed description of a workflow for variant calling using next-generation sequencing in Norway spruce (Picea abies). The workflow that starts with raw sequencing reads and proceeds through read mapping to variant calling and variant filtering. We illustrate the pipeline using data derived from both whole-genome resequencing data and reduced-representation sequencing. We highlight possible problems and pitfalls of using next-generation sequencing data for genotyping stemming from the complex genome structure of conifers and how those issues can be mitigated or eliminated.
The phase separation-dependent FUS interactome reveals nuclear and cytoplasmic function of liquid-liquid phase separation
Authors: Reber Stefan , Lindsay Helen , Devoy Anny , Jutzi Daniel , Mechtersheimer Jonas , Domanski Michal , Mühlemann Oliver , Barabino Silvia M.L. , Ruepp Marc-David
Published: October 2019

Liquid-liquid phase separation (LLPS) of proteins and RNAs has emerged as the driving force underlying the formation of membrane-less organelles. Such biomolecular condensates have various biological functions and have been linked to disease. One of the best studied proteins undergoing LLPS is Fused in Sarcoma (FUS), a predominantly nuclear RNA-binding protein. Mutations in FUS have been causally linked to Amyotrophic Lateral Sclerosis (ALS), an adult-onset motor neuron disease, and LLPS followed by aggregation of cytoplasmic FUS has been proposed to be a crucial disease mechanism. In spite of this, it is currently unclear how LLPS impacts the behaviour of FUS in cells, e.g. its interactome. In order to study the consequences of LLPS on FUS and its interaction partners, we developed a method that allows for the purification of phase separated FUS-containing droplets from cell lysates. We observe substantial alterations in the interactome of FUS, depending on its biophysical state. While non-phase separated FUS interacts mainly with its well-known interaction partners involved in pre-mRNA processing, phase-separated FUS predominantly binds to proteins involved in chromatin remodelling and DNA damage repair. Interestingly, factors with function in mitochondria are strongly enriched with phase-separated FUS, providing a potential explanation for early changes in mitochondrial gene expression observed in mouse models of ALS-FUS. In summary, we present a methodology that allows to investigate the interactome of phase-separating proteins and provide evidence that LLPS strongly shapes the FUS interactome with important implications for function and disease.
Reversal learning in Drosophila larvae
Authors: Mancini Nino , Hranova Sia , Weber Julia , Weiglein Aliće , Schleyer Michael , Weber Denise , Thum Andreas S. , Gerber Bertram
Published: October 2019

Adjusting behavior to changed environmental contingencies is critical for survival, and reversal learning provides an experimental handle on such cognitive flexibility. Here, we investigate reversal learning in larval Drosophila. Using odor–taste associations, we establish olfactory reversal learning in the appetitive and the aversive domain, using either fructose as a reward or high-concentration sodium chloride as a punishment, respectively. Reversal learning is demonstrated both in differential and in absolute conditioning, in either valence domain. In differential conditioning, the animals are first trained such that an odor A is paired, for example, with the reward whereas odor B is not (A+/B); this is followed by a second training phase with reversed contingencies (A/B+). In absolute conditioning, odor B is omitted, such that the animals are first trained with paired presentations of A and reward, followed by unpaired training in the second training phase. Our results reveal “true” reversal learning in that the opposite associative effects of both the first and the second training phase are detectable after reversed-contingency training. In what is a surprisingly quick, one-trial contingency adjustment in the Drosophila larva, the present study establishes a simple and genetically easy accessible study case of cognitive flexibility.
Better memory for intrinsic versus extrinsic details underlies the enhanced recollective experience of negative events
Authors: Mihaylova Mariela , Vuilleumier Patrik , Rimmele Ulrike
Published: October 2019

Why we remember emotional events with an increased subjective sense of remembering (SSR) is unclear. SSR for neutral events is linked to memory for various kinds of details. Using the Remember/Know paradigm, participants provided written justifications of their Remember responses indicating what they specifically recollected about a negative or neutral photo seen during encoding. Crucially, Remember responses for negative photos were more often linked to memory for details of the stimuli (intrinsic details) versus details related to external associations (extrinsic details) or emotional reaction at encoding, suggesting that memory for intrinsic details underlies the enhanced SSR of negative stimuli.
Is the edulcorate power of two intense sweeteners sucralose and stevia same in ice cream and frozen desserts?
Authors: Bragion Daniela Mariana de Lima , Bolini Helena Maria André
Published: October 2019

Purpose

Carob has been proposed as a healthy, stimulant-free alternative to chocolate in frozen desserts. In order to make carob a viable and attractive alternative, food producers need to know how it interacts with sweeteners and frozen dessert dispersion matrices. The purpose of this paper is to find the optimal sweetener concentration in three plant-based frozen desserts and carob-flavoured milk dispersion matrix ice cream.

Design/methodology/approach

The ideal sucrose concentrations (per cent) were determined through an affective test using the “just-about-right” scale for carob-flavoured frozen desserts made with cashew nut, coconut and soy beverage, as well as milk dispersion matrix. The sweetness equivalence of artificial sweeteners relative to sucrose was determined by the magnitude estimation test.

Findings

The authors identified the concentrations of sucrose, stevia and sucralose that produced ideal sweetness in carob-flavoured frozen desserts. Concentrations for soy-based frozen desserts differed from the other dispersion mediums tested. Plant-based frozen desserts exhibited a higher ratio of sweetening power of stevia and sucralose to sucrose compared to milk-based ice cream by a factor of 1.18 and 1.14, respectively.

Originality/value

This study undertook a comprehensive survey of a dairy-free and chocolate-free alternative to chocolate ice cream and found new sweetener interactions with dispersion matrices in carob-flavoured frozen desserts. The findings in this study can be applied in the development of carob-flavoured soybean-, coconut-, cashew nut- and milk-based frozen desserts.
Factors influencing travelers’ behavioral intentions to use P2P accommodation based on trading activity: Airbnb vs Couchsurfing
Authors: Aruan Daniel Tumpal H. , Felicia Felicia
Published: October 2019

Purpose

The growth of information and communication technology and the appearance of the sharing economy have affected the market. This trend will potentially create a competitive transformation, especially in the accommodation sector. While Airbnb has become the leader in the sharing economy, more competitors are coming into the market, some with different business propositions and positioning strategies, thereby offering different points of differences (PODs). The purpose of this study is to identify and compare the factors that influence the usage of peer-to-peer (P2P) accommodation services for trading activity (renting vs lending), particularly between Airbnb and Couchsurfing. More specifically, this study examines the causal relationships among some major factors that influence customers’ purchase intentions, such as perceived risk, perceived value, price sensitivity and word of mouth.

Design/methodology/approach

A total of 400 millennial respondents – 200 for each service – who have used the respective mobile applications participated in the online survey. Using structural equation modeling, the analysis revealed that the model acts differently across the groups.

Findings

The results revealed that Airbnb respondents paid more attention to perceived risks when booking the accommodation, thus indicating that they are more risk-averse, whereas Couchsurfing’s users sought the perceived value that they would receive at the destination.

Practical implications

The findings of this study are beneficial for Airbnb and Couchsurfing in particular and players in the industry in general.

Originality/value

This study reveals that factors that influence the intention to use the sharing economy platform work differently based on the form of trading activities.
Design and evaluation of mobile sensing technologies for identifying medicines by people with visual disabilities
Authors: Façanha Agebson Rocha , Carneiro Araújo Maria Conceição , Viana Windson , Sánchez Jaime
Published: October 2019

Purpose

People with visual impairments may have difficulty in identifying information, either on a bottle or package of medicine. As a result, many of them need the help of a third party to discern which medication they should take. In this perspective, this study aims to assist people with visual impairments to identify their medicine by using mobile sensing technologies.

Design/methodology/approach

The authors have developed three versions of a mobile application. They use three technologies, namely, near field communication, QR code and magnetic field, for drug identification. The entire development process was based on user-centered design. And, the authors also performed an initial usability assessment of these applications with ten users who were blind.

Findings

Preliminary results show user preference for the near field communication approach and reinforce some known drawbacks concerning the use of QR code by people with visual impairments.

Research limitations/implications

Although the authors have evaluated these technologies with few mobile devices, they perceived that the acquired values of the magnetic field suffered distortions culminating, in some cases, in a non-identification of the medicine, or even in incorrect identification.

Practical implications

Current mobile device magnet sensors are not yet robust to be used for medicine identification.

Social implications

Mobile apps combined with medicine identification can contribute to the autonomy of people who are blind.

Originality/value

The main contribution of this paper is to integrate and analyze distinct mobile-based sensing technologies for identifying medicines by people with visual impairments.
Dynamic impact of social network on knowledge contribution loafing in mobile collaboration: a hidden Markov model
Authors: Jiang Shan , Zhang Xi , Cheng Yihang , Xu Dongming , Ordoñez De Pablos Patricia , Wang Xuyan
Published: October 2019

Purpose

Social loafing in knowledge contribution (namely, knowledge contribution loafing [KCL]) usually happens in group context, especially in the mobile collaboration tasks. KCL shows dynamic features over time. However, most previous studies are based on static assumption, that is, KCL will not change over time. This paper aims to reveal the dynamics of KCL in mobile collaboration and analyze how network centrality influences KCL states considering the current loafing state.

Design/methodology/approach

This study is based on empirical study design. Real mobile collaboration behavioral data related to knowledge contribution were collected to investigate the dynamic relationship between network centrality and KCL. In total, 4,127 chat contents were collected through Slack (a mobile collaboration APP). The text data were first analyzed using the text analysis method and then analyzed by a machine learning method called hidden Markov model.

Findings

First, the results reveal the inner structure of KCL, showing that it has three states (low, medium and high). Second, it is found that network centrality positively influences individuals involved in medium and high loafing state, while it has a negative influence on individuals with low loafing state.

Research limitations/implications

The limitations are related to the single machine learning method and no subdivision of social network. First, this paper only uses one kind of text classification model (TF-IDF) to divide chat contents, which may not be superior to other classification models. This paper considers the eigenvector centrality, and not further divides the social network into advice network and expressive network.

Practical implications

This study helps companies infer tendency of different KCL and dynamically re-organize a mobile collaborative team for better knowledge contribution.

Originality/value

First, previous studies based on static assumptions regarding KCL as static and the relationship between loafing reducing mechanisms and team members KCL does not change over time. This study relaxes static assumptions and allows KCL to change during the process of collaboration. Second, this study allows the impact of network centrality to be different when members are in different KCL states.
Strategic cost modelling and optimisation for highway asset maintenance
Authors: Tee Kong Fah , Ekpiwhre Ejiroghene
Published: October 2019

Purpose

The purpose of this paper is to propose and confer a strategic cost model as a concept for good decision making for highway asset treatment in the transport industry.

Design/methodology/approach

The paper is based on asset performance condition and treatment renewals using a five-point performance for developing prospective treatment strategies. The strategic cost model is presented in the similitude of picturesque and its outcomes via an exploratory data analysis.

Findings

The results articulate the best maintenance plan for the forthcoming and future years. The strategic cost model uses the combination of the current condition band, the sample area and likely treatment cost for proposing the optimal treatment solution based on consideration of desired treatment level.

Practical implications

The strategic cost model is suitable for outlining the asset performance condition, treatment renewals and analytical cost optimisation. The formulated analytical cost model and developed prospective strategies enable good decision making, long-term contract negotiations and whole life cost maintenance and management.

Originality/value

Embracing eminent performance condition from the research area of lifecycle planning and deterioration models of a physical asset, a prospective cost strategy for asset maintenance is proposed in the study. The resultant treatment strategies using the analytical approach portray the ability that enables the adaptation of expected outcomes.
What s-commerce implies? Repurchase intention and its antecedents
Authors: Lim Xin-Jean , Cheah Jun-Hwa , Waller David S. , Ting Hiram , Ng Siew Imm
Published: October 2019

Purpose

The purpose of this paper is to examine the impact of social commerce (s-commerce) cues (i.e. trust, compatibility, reliability and responsiveness) on repurchase intention in apparel s-commerce along with the mediating effect of customer engagement and the moderating effect of s-commerce navigation.

Design/methodology/approach

Using the purposive sampling technique, face-to-face survey was administered to Gen-Y social media users in Malaysia. Subsequently, 384 respondents were sampled. Partial least squares-structural equation modeling was used to perform the analyses.

Findings

S-commerce cues have a positive effect on customer engagement, which in turn leads to repurchase intention of apparel among Gen-Y. Particularly, customer engagement also mediates the relationship between s-commerce cues and repurchase intention. S-commerce navigation is found to moderate the effect of engagement on repurchase intention.

Research limitations/implications

The findings are derived from the perception of Gen-Y in Malaysia and do not represent the entire population. Future research could investigate the same phenomena across generations and consider heterogeneity issues to provide more insights.

Practical implications

Apparel s-commerce retailers are suggested to engage with customers more in the e-retail environment to build a lasting relationship. Contextual factors such as ease of navigation should be observed to enhance the desired response of diverse customers today.

Originality/value

This study adds to the growing body of knowledge on relationship marketing by assessing the impact of customer engagement and navigation on the relationships between s-commerce cues and repurchase intention in the contemporary setting.
Social media marketing and customers’ passion for brands
Authors: Mukherjee Kaustav
Published: October 2019

Purpose

The modern-day digital marketers use social media as a tool for brand awareness and customer engagement. However, whether social media marketing can actually impact deeper into the users’ emotional level and instigate purchase intention is a popular moot point. The purpose of this paper is to investigate as to whether social media marketing is effective in inciting a sense of arousal or passion for the advertised brands and finally generate a purchase intention in the minds of the social media users.

Design/methodology/approach

A convenient sampling procedure was followed to collect relevant data using a structured questionnaire. The technique of structural equation modelling was used for model building using the software, AMOS 18.

Findings

The study reveals that efficient use of social media for marketing communications can generate a passion for the advertised brands in the social media users’ minds, as well as instigate a brand purchase intention.

Research limitations/implications

The study has been restricted to Indian smartphone customers who also spend a substantial amount of time on social media.

Practical implications

The use of social media for online customer engagement is a smart strategy that can be employed by digital marketers in order to emotionally connect the advertised brand with the users of social media.

Originality/value

This study is probably the first to investigate the direct impact of social media marketing on users’ brand passion.
How qualitative research can infuse teaching in accounting
Authors: Jack Lisa , Saulpic Olivier
Published: October 2019

Purpose

This paper aims to present an understanding of what it means to infuse teaching with qualitative research and to introduce the papers in the special issue.

Design/methodology/approach

This is an introductory essay that provides a brief overview and analysis of the ideas to be found in the issue.

Findings

The special issue contributes to the understanding of the integration of teaching and research by showing how the authors as actors, as teacher-researchers, bring not just the findings but also reflexivity into the classroom and take knowledge out into both research and teaching. The papers in this issue all consider the agency of teachers in bringing an epistemology into the classroom, and in developing that epistemology.

Originality/value

The papers in this issue go beyond concepts of research-led teaching and the research-teaching nexus towards reflective pieces that develop understanding of epistemology rather than more conventional reports of classroom interventions.
Sustainable tourism certification, local governance and management in dealing with overtourism in East Africa
Authors: Maingi Shem Wambugu
Published: October 2019

Purpose

The purpose of this paper is to understand the causes and effects of overtourism within the East African region. The paper examines how national governments address the problem of overtourism in East Africa and determines underlying principles and best practice in sustainable tourism certification, local governance and management in dealing with overtourism.

Design/methodology/approach

To address the objectives, the researcher conducted an exploratory experience survey research design. The study examines the different articles in the subject area and interview findings of practitioner respondents. Based on a review of the existing dimensions of overtourism, the effects of overtourism and local governance, the study sought to derive a holistic (systemic and integrated) perspective on the subject matter.

Findings

The paper presents valuable evidence from industry practitioners on the effects of overtourism in East Africa by classifying the effects as psychological, physical, economic and socio-cultural. Further, the paper examines how East African governments address the problem of overtourism and gives recommendations on ways to enforce, govern and coordinate implementation of tourism regulations and policies in East Africa.

Originality/value

This paper is the first to address overtourism in the context of East Africa, examining different local and innovative approaches to dealing with the impacts of overtourism in an East African context.