bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing the impact of secondary school reopening strategies on within-school COVID-19 transmission and absences: a modelling study
Authors: Leng Trystan , Hill Edward M. , Thompson Robin N. , Tildesley Michael J. , Keeling Matt J. , Dyson Louise
Published: February 2021

Background

Strategies involving rapid testing have been suggested as a way of reopening schools that minimises absences while controlling transmission. We assess the likely impact of rapid testing strategies using lateral flow tests (LFTs) on infections and absences in secondary schools, compared to a policy of isolating year group bubbles upon a pupil returning a positive polymerase chain reaction (PCR) test.

Methods

We developed an individual-based model of a secondary school formed of exclusive year group bubbles (five year groups, with 200 pupils per year). By simulating infections over the course of a seven-week half-term, we compared the impact of differing strategies on transmission, absences, and testing volume. We also considered the sensitivity of results to underlying model assumptions.

Findings

Repeated testing of year-group bubbles following case detection or regular mass-testing strategies result in a modest increase in infections compared to the policy of isolating year-group bubbles, but substantially reduce absences. When combined these two testing strategies can reduce infections to levels lower than would occur under year-group isolation, although such a policy requires a high volume of testing.

Interpretation

Our results highlight the conflict between the goals of minimising within-school transmission, minimising absences and minimising testing burden. While mass and targeted testing strategies can reduce school transmission and absences, it may lead to a large number of daily tests.
Evaluating COVID-19 reporting data in the context of testing strategies across 31 LMICs
Authors: Van Gordon Mollie M. , McCarthy Kevin A. , Proctor Joshua L. , Hagedorn Brittany L.
Published: February 2021

0.1

Background

COVID-19 case counts are the predominant measure used to track epidemiological dynamics and inform policy decision-making. Case counts, however, are influenced by testing rates and strategies, which have varied over time and space. A method to consistently interpret COVID-19 case counts in the context of other surveillance data is needed, especially for data-limited settings in low- and middle-income countries (LMICs).

0.2

Methods

We leverage statistical analyses to detect changes in COVID-19 surveillance data. We apply the pruned exact linear time change detection method for COVID-19 case counts, number of tests, and test positivity rate over time. With this information, we categorize change points as likely driven by epidemiological dynamics or non-epidemiological influences such as noise.

0.3

Findings

Higher rates of epidemiological change detection are more associated with open testing policies than with higher testing rates. We quantify alignment of non-pharmaceutical interventions with epidemiological changes. LMICs have the testing capacity to measure prevalence with precision if they use randomized testing. Rwanda stands out as a country with an efficient COVID-19 surveillance system. Sub-national data reveal heterogeneity in epidemiological dynamics and surveillance.

0.4

Interpretation

Relying solely on case counts to interpret pandemic dynamics has important limitations. Normalizing counts by testing rate mitigates some of these limitations, and open testing policy is key to efficient surveillance. Our findings can be leveraged by public health officials to strengthen COVID-19 surveillance and support programmatic decision-making.

0.5

Funding

This publication is based on models and data analysis performed by the Institute for Disease Modeling at the Bill & Melinda Gates Foundation.

Research in Context

Evidence before this study

We searched for articles on the current practices, challenges, and proposals for COVID-19 surveillance in LMICs. We used Google Scholar with search terms including “COVID surveillance.” Existing studies were found to be qualitative, anecdotal, or highly location-specific.

Added value of this study

We developed a quantitative method that makes use of limited information available from LMICs. Our approach improves interpretation of epidemiological data and enables evaluation of COVID-19 surveillance dynamics across countries.

Implications of all the available evidence

Our results demonstrate the importance of open testing for strong surveillance systems, bolstering existing anecdotal evidence. We show strong alignment across LMICs between non-pharmaceutical interventions and epidemiological changes. We demonstrate the importance of considering sub-national heterogeneity of epidemiological dynamics and surveillance.
Implications of climatic and demographic change for seasonal influenza dynamics and evolution
Authors: Baker Rachel E. , Yang Qiqi , Worby Colin J. , Yang Wenchang , Saad-Roy Chadi M. , Viboud Cecile , Shaman Jeffrey , Metcalf C. Jessica E. , Vecchi Gabriel , Grenfell Bryan T.
Published: February 2021

Seasonal influenza causes a substantial public health burden, as well as being a key substrate for pandemic emergence. Future climatic and demographic changes may alter both the magnitude, frequency and timing of influenza epidemics and the prospects for pathogen evolution, however, these issues have not been addressed systematically. Here, we use a parsimonious influenza model, grounded in theoretical understanding of the link between climate, demography and transmission to project future changes globally. We find that climate change generally acts to reduce the intensity of influenza epidemics as specific humidity increases. However, this reduction in intensity is accompanied by increased seasonal epidemic persistence with latitude, which may increase suitability for year-round local influenza evolution. Using a range of population growth scenarios, we find that the number of global locations with high evolution suitability may double by 2050. High population growth in tropical Africa could thus make this region a locus of novel strain emergence, shifting the current focus from South East Asia.
The Missing Science: Epidemiological data gaps for COVID-19 policy in the United States
Authors: Bhatia Rajiv , Sledge Isabella , Baral Stefan
Published: February 2021

We report on a scoping study of COVID-19 epidemiological data available for COVID-19 policy and management decisions for U.S. settings. We synthesize current US Centers for Disease and Control and Prevention (CDC) estimates for parameter of infectious transmission, infection severity, and disease burden, and summarize epidemiologic contributions to these parameters published by CDC-affiliated investigators through Oct 30, 2020. Authoritative estimates of most infectious transmission and infection severity parameters exist but rely primarily on data from studies conducted in non-U.S. populations. Estimates of secondary infection risks for household, workplace, school, or other community settings are lacking and estimates of the clinical fraction remain uncertain. The CDC reports multiple disease incidence and prevalence measures at national and state geographies, including some measures disaggregated by age group, race/ethnicity and sex; however, nationally uniform disease burden measures are not available at the sub-state level or for sub-populations defined by exposure setting, limiting opportunities for targeted interventions. CDC-affiliated investigators authored 133 quantitative studies on COVID-19 through Oct 30, 2020; however only 34 employed analytic methods. The remainder were descriptive. Of the 34 analytic studies, eleven reported on risk factors for infection, seven reported on risk factors for severe disease, three on symptomatic infections, three reported secondary infection risks, and four reported on indirect pandemic effects. Gaps remain in the epidemiological data required for an efficient and equitable public health policy response to COVID-19. The existence of these gaps one year after the onset of the COVID-19 pandemic underscores the need for standardizing data collection and research priorities and protocols in the context of a rapidly emerging infectious disease epidemics.
Identification of a rapidly-spreading triple mutant for high-level metabolic insecticide resistance inAnopheles gambiaeprovides a real-time molecular diagnostic for anti-malarial intervention deployment
Authors: Njoroge Harun , van’t Hof Arjen , Oruni Ambrose , Pipini Dimitra , Nagi Sanjay C. , Lynd Amy , Lucas Eric R. , Tomlinson Sean , Grau-Bove Xavi , McDermott Daniel , Wat’senga Francis T. , Manzambi Emile Z. , Agossa Fiacre R. , Mokuba Arlette , Irish Seth , Kabula Bilali , Mbogo Charles , Bargul Joel , Paine Mark J.I. , Weetman David , Donnelly Martin J.
Published: February 2021

Insecticide resistance provides both an increasingly pressing threat to the control of vector-borne diseases and insights into the remarkable capacity of natural populations to show rapid evolutionary responses to contemporary selection. Malaria control remains heavily dependent on deployment of pyrethroid insecticides, primarily in long lasting insecticidal nets (LLINs), but resistance in the major malaria vectors has increased over the last 15 years in concert with dramatic expansion of LLIN distributions. Identifying genetic mechanisms underlying high-level resistance in mosquitoes, which may almost entirely overcome pyrethroid efficacy, is crucial for the development and deployment of potentially resistance-breaking tools. Using theAnopheles gambiae1000 genomes (Ag1000g) data we identified a very recent selective sweep in mosquitoes from Uganda which localized to a cluster of cytochrome P450 genes, including some commonly implicated in resistance. Further interrogation revealed a haplotype involving a trio of mutations, a nonsynonymous point mutation inCyp6p4(I236M), an upstream insertion of a partial Zanzibar-like transposable element (TE) and a duplication of theCyp6aa1gene. The mutations appear to have originated recently inAn. gambiaefrom the Kenya-Uganda border region around Lake Victoria, with stepwise replacement of the double-mutant (Zanzibar-like TE andCyp6p4-236M) with the triple-mutant haplotype (includingCyp6aa1duplication), which has spread into the Democratic Republic of Congo and Tanzania. The triple-mutant haplotype is strongly associated with increased expression of genes able to metabolise pyrethroids and is strongly predictive of resistance to pyrethroids most notably deltamethrin, a commonly-used LLIN insecticide. Importantly, there was increased mortality in mosquitoes carrying the triple-mutation when exposed to nets co-treated with the synergist piperonyl butoxide (PBO). Frequencies of the triple-mutant haplotype remain spatially variable within countries, suggesting an effective marker system to guide deployment decisions for limited supplies of PBO-pyrethroid co-treated LLINs across African countries. Duplications of theCyp6aa1gene are common inAn. gambiaeacross Africa and, given the enzymes metabolic activity, are likely to be a useful diagnostic for high levels of pyrethroid resistance.
Effect of ligand sensing on flagellar bundle formation in bacteria
Authors: Agrawal Megha , Chakraborty Soumyadeep , Tirumkudulu Mahesh S. , Venkatesh K.V
Published: February 2021

E. coliswims in liquid media by rotating long appendages called flagella. The direction of rotation of each flagellum is governed by a transmembrane rotary nanomotor, which receives signals from ligand-specific receptors. Attractants bias the motor to rotate in CCW direction causing flagella to bundle and provide thrust for locomotion. Recent studies have shown that sensing not only leads to increase in CCW bias but also increases the motor rotation speed due to the recruitment of additional stator units bound to the rotor. Despite the detailed studies on bacterial motility, the effect of ligand sensing on the synchronization of flagellar filaments leading to bundle formation and changes in bundle geometry are not clear. In this work, we performed real-time imaging of the flagellar bundle of swimming cells in metabolising (glucose) and non-metabolisable (2-Deoxy-d-glucose) attractants. We characterized bundles during swimming by measuring visible distal length and the spread of filaments at poles. We show that sensing of attractant by receptor leads to the formation of tight bundles when compared to control buffer. Contrary to previous studies, the swimming speeds were proportional to the bundle tightness with the latter dependent not only on the bias but also on the torque exerted by the motor. We further show that the observed wiggles in the swimming trajectory of cells is directly proportional to the spread angles of bundle and is effected by both motor CCW bias and torque. Mutant cells, which were rendered non-motile due to the absence of the PTS (phosphotransferase system) sugar uptake mechanism, exhibited motility when exposed to the non-metabolisable attractant confirming that mere sensing can induce torque in flagellar motor. These results clarify the role of sensing and metabolism on bundle formation and its impact on the motility of cells.

Statement of significance

Peritrichously flagellatedE. coliswims away or towards ligands by biasing the direction of rotation of its flagellar motor. Recently, it has been shown that motor speed is also modulated on merely sensing a ligand. How does this impact flagellar bundle formation and swimming behavior? Using real-time imaging, we show that the bundle geometry changes in response to both metabolisable and non-metabolisable ligand. Mere sensing of a ligand temporarily increases the motor torque and CCW bias that causes tight flagellar bundles and leads to smooth swimming trajectories at high speeds. Our result provides strong evidence of a new signalling pathway that controls the flagellar motor speed to enable the bacteria to respond efficiently to changes in its environment.
Polymetallic nodules are essential for food-web integrity of a prospective deep-seabed mining area in Pacific abyssal plains
Authors: Stratmann Tanja , Soetaert Karline , Kersken Daniel , van Oevelen Dick
Published: February 2021

Polymetallic nodule fields provide hard substrate for sessile organisms on the abyssal seafloor between 3,000 and 6,000 m water depth. Deep-seabed mining targets these mineral-rich nodules and will likely modify the consumer-resource (trophic) and substrate-providing (non-trophic) interactions within the abyssal food web. However, the importance of nodules and their associated sessile fauna in supporting food-web integrity remains unclear. Here, we use seafloor imagery and published literature to develop highly-resolved trophic and non-trophic interaction webs for the Clarion-Clipperton Fracture Zone (CCZ, central Pacific Ocean) and the Peru Basin (PB, south-east Pacific Ocean) and to assess how nodule removal will modify these networks. The CCZ interaction web included 1,028 compartments connected with 59,793 links and the PB interaction web consisted of 342 compartments and 8,044 links. We show that knock-down effects of nodule removal resulted in a 17.9% (CCZ) to 20.8% (PB) loss of all compartments and 22.8% (PB) to 30.6% (CCZ) loss of network links. Subsequent analysis identified stalked glass sponges living attached to the nodules as key structural species that supported a high diversity of associated fauna. We conclude that polymetallic nodules are critical for food-web integrity and that their absence will likely result in reduced local benthic biodiversity.
Autocrine regulation of adult neurogenesis by the endocannabinoid 2-arachidonoylglycerol (2-AG)
Authors: Schuele Lena-Louise , Schürmann Britta , Bilkei-Gorzo Andras , Zimmer Andreas , Leidmaa Este
Published: February 2021

The endocannabinoid system modulates adult hippocampal neurogenesis by promoting the proliferation and survival of neural stem and progenitor cells (NSPCs). Specifically, deleting cannabinoid receptors on NSPCs or the constitutive deletion of the endocannabinoid 2-arachidonoylglycerol (2-AG) producing enzyme diacylglycerol lipase alpha (DAGLa) disrupts adult neurogenesis. However, it is not known which cells are the producers of 2-AG relevant to neurogenesis. In this paper, we investigated the cellular source of endocannabinoids in the subgranular zone (SGZ) of the hippocampus, an important neurogenic niche. For this purpose, we used two complementary Cre-deleter mouse strains to delete DAGLa either in neurons or astroglia and NSPCs. Surprisingly, neurogenesis was not altered in mice with a deletion ofDaglain neurons (Syn-Dagla KO), although they are the main source for the endocannabinoids in the brain. In contrast, mice with a specific inducible deletion ofDaglain NPSCs and astrocytes (GLAST-CreERT2-Dagla KO) showed a strongly impaired neurogenesis with significantly reduced proliferation and survival of newborn cells. These results identifyDaglain NSPCs in the SGZ of dentate gyrus or in astrocytes, as the cellular source for 2-AG in adult hippocampal neurogenesis. In summary, 2-AG produced by progenitor cells or astrocytes in the SGZ regulates adult hippocampal neurogenesis.

DAGLa in neuronal progenitor cells in the SGZ of dentate gyrus is identified as the cellular source for 2-AG in adult hippocampal neurogenesis.
Small intestine lactobacilli growth promotion and immunomodulation in weaner pigs fedCyberlindnera jadiniiyeast high inclusion diet and exposed to enterotoxigenicEscherichia coliF4+: O149
Authors: Iakhno S. , Hellestveit S.S. , Umu Ö.C.O. , Bogevik L.T. , Åkesson C.P. , Göksu A.B. , Press C.McL. , Mydland L.T. , Øverland M. , Sørum H.
Published: February 2021

1

EnterotoxigenicEscherichia coli(ETEC) F4+: O149 is a causative agent for the development of post-weaning diarrhoea (PWD) in pigs that contributes to production losses. Yeast cell wall components used as a feed additive can modulate gut immunity and help protect animals from enteric infections. This work investigated how a novel yeast diet with high inclusion of yeast proteins (40% of crude protein) affected the course of ETEC mediated diarrhoea in weaner piglets from a farm with or without a history of post-weaning diarrhoea. We found that immune response to F4abETEC infection and appetite of the animals were altered by high inclusionC. jadiniiyeast. The results indicate that the novel diet can support the diseased animals either directly through the effect of yeast beta-glucans and mannans or indirectly through the promotion of small intestine lactobacilli or both.
With great power comes great responsibility: an analysis of sustainable forest management quantitative indicators in the DPSIR framework
Authors: Paillet Y. , Campagnaro T. , Burrascano S. , Gosselin M. , Ballweg J. , Chianucci F. , Dorioz J. , Marsaud J. , Maciejewski L. , Sitzia T. , Vacchiano G.
Published: February 2021

The monitoring of environmental policies in Europe has taken place since the 1980s and still remains a challenge for decision- and policy-making. For forests, it is concretized through the publication of a State Of Europe’s Forests every five years, the last report just been released. However, the process lacks a clear analytical framework and appears limited to orient and truly assess sustainable management of European forests. We classified the 34 quantitative sustainable forest management indicators in the Driver-Pressure-State-Impact-Response (DPSIR) framework to analyse gaps in the process. In addition, we classified biodiversity-related indicators in the simpler Pressure-State-Response (PSR) framework. We showed that most of the sustainable forest management indicators assess the state of European forests, but almost half could be classified in another DPSIR category. For biodiversity, most indicators describe pressures, while direct taxonomic state indicators are very few. Our expert-based classification show that sustainable forest management indicators are unbalanced regarding the DPSIR framework. However, completing this framework with other indicators would help to have a better view and more relevant tools for decision-making. The results for biodiversity were comparable, but we showed that some indicators from other criteria than the one dedicated to biodiversity could also help understanding threats and actions concerning it. Such classification helps in the decision process, but is not sufficient to fully support policy initiative. In particular, the next step would be to better understand the links between DPSIR and PSR categories.
Otolith-based discrimination of cod ecotypes and the effect of growth rate
Authors: Pétur Jónsson Einar , Campana Steven E. , Sólmundsson Jón , Jakobsdóttir Klara B. , Bárðarson Hlynur
Published: February 2021

Otolith shape has previously been used to identify ecotypes within the Icelandic cod (Gadus morhua) stock, using DST profiles to validate the results. Fish otolith shape variation has repeatedly been found to be largely determined by growth rate. To examine the effect of growth rate on the relationship between otolith shape and cod ecotypes (using the Pan I genotype as a proxy for ecotype), 826 archived sagittal otoliths collected over a 52 year sampling period were retrieved, the individual growth rate calculated, and otolith shape described using both Normalized Elliptic Fourier transform and Discrete Wavelet transform. Discriminant functions of otolith shape yielded high ecotype classification success, whether using Fourier or Wavelet descriptors, but only when excluding a heterozygous genotype from the analysis. The otolith shape variability of this genotype lowered the classification success, while otolith shape, in turn, was significantly affected by growth rate and cohort. Growth rate differences previously reported for the ecotypes were present, but were less marked than expected and indeed, growth rate variance attributable to ecotype identity was dwarfed by cohort- and location-related variance in growth. Such a strong effect of growth rate suggests that cod ecotype discrimination based on otolith shape is sensitive to both temporal and spatial variations in growth, which can mask the effect of ecotype-related growth rate differences on otolith shape.
Evolutionary divergence of locomotion in two related vertebrate species
Authors: Rajan Gokul , Lafaye Julie , Carbo-Tano Martin , Duroure Karine , Faini Giulia , Tanese Dimitrii , Panier Thomas , Candelier Raphaël , Henninger Jörg , Britz Ralf , Judkewitz Benjamin , Gebhardt Christoph , Emiliani Valentina , Debregeas Georges , Wyart Claire , Del Bene Filippo
Published: February 2021

Locomotion exists in diverse forms in nature and is adapted to the environmental constraints of each species1. However, little is known about how closely related species with similar neuronal circuitry can evolve different navigational strategies to explore their environments. We established a powerful approach in comparative neuroethology to investigate evolution of neuronal circuits in vertebrates by comparing divergent swimming pattern of two closely related larval fish species,Danionella translucida(DT) andDanio rerioor zebrafish (ZF)2,3. During swimming, we demonstrate that DT utilizes lower half tail-beat frequency and amplitude to generate a slower and continuous swimming pattern when compared to the burst-and-glide swimming pattern in ZF. We found a high degree of conservation in the brain anatomy between the two species. However, we revealed that the activity of a higher motor region, referred here as the Mesencephalic Locomotion Maintenance Neurons (MLMN) correlates with the duration of swim events and differs strikingly between DT and ZF. Using holographic stimulation, we show that the activation of the MLMN is sufficient to increase the frequency and duration of swim events in ZF. Moreover, we propose two characteristics, availability of dissolved oxygen and timing of swim bladder inflation, which drive the observed differences in the swim pattern. Our findings uncover the neuronal circuit substrate underlying the evolutionary divergence of navigational strategies and how they are adapted to their respective environmental constraints.
Disordered information processing dynamics in experimental epilepsy
Authors: Clawson Wesley , Madec Tanguy , Ghestem Antoine , Quilichini Pascale P , Battaglia Demian , Bernard Christophe
Published: February 2021

Neurological disorders share common high-level alterations, such as cognitive deficits, anxiety, and depression. This raises the possibility of fundamental alterations in the way information conveyed by neural firing is maintained and dispatched in the diseased brain. Using experimental epilepsy as a model of neurological disorder we tested the hypothesis of altered information processing, analyzing how neurons in the hippocampus and the entorhinal cortex store and exchange information during slow and theta oscillations. We equate the storage and sharing of information to low level, or primitive, information processing at the algorithmic level, the theoretical intermediate level between structure and function. We find that these low-level processes are organized into substates during brain states marked by theta and slow oscillations. Their internal composition and organization through time are disrupted in epilepsy, loosing brain state-specificity, and shifting towards a regime of disorder in a brain region dependent manner. We propose that the alteration of information processing at an algorithmic level may be a mechanism behind the emergent and widespread co-morbidities associated with epilepsy, and perhaps other disorders.
A benchmarking of human mitochondrial DNA haplogroup classifiers from whole-genome and whole-exome sequence data
Authors: García-Olivares Víctor , Muñoz-Barrera Adrián , Lorenzo-Salazar José Miguel , Zaragoza-Trello Carlos , Rubio-Rodríguez Luis A. , Díaz-de Usera Ana , Jáspez David , Campos Antonio Iñigo , González-Montelongo Rafaela , Flores Carlos
Published: February 2021

The mitochondrial genome (mtDNA) is of interest for a range of fields including evolutionary, forensic, and medical genetics. Human mitogenomes can be classified into evolutionary related haplogroups that provide ancestral information and pedigree relationships. Because of this and the advent of high-throughput sequencing (HTS) technology, there is a diversity of bioinformatic tools for haplogroup classification. We present a benchmarking of the 11 most salient tools for human mtDNA classification using empirical whole-genome (WGS) and whole-exome (WES) short-read sequencing data from 36 unrelated donors. Besides, because of its relevance, we also assess the best performing tool in third-generation long noisy read WGS data obtained with nanopore technology for a subset of the donors. We found that, for short-read WGS, most of the tools exhibit high accuracy for haplogroup classification irrespective of the input file used for the analysis. However, for short-read WES, Haplocheck and MixEmt were the most accurate tools. Based on the performance shown for WGS and WES, and the accompanying qualitative assessment, Haplocheck stands out as the most complete tool. For third-generation HTS data, we also showed that Haplocheck was able to accurately retrieve mtDNA haplogroups for all samples assessed, although only after following assembly-based approaches (either based on a referenced-based assembly or a hybridde novoassembly). Taken together, our results provide guidance for researchers to select the most suitable tool to conduct the mtDNA analyses from HTS data.
Contribution of quasi-fibrillar superstructures in peroxide quenching by collagen peptides derived from fish processing by-products and their application as natural food additives
Authors: Saleem K , Dey Pritha , Sumeet Charitha , Bajaj Mayur , Geetika Y , Vishwadeep A , Tagadghar Pawan , Banerjee Pradipta
Published: February 2021

This study attempts to identify the significant role played by the secondary structure of collagen-derived peptides that are involved in lipid peroxide quenching in food products. Collagen was extracted from the skin of Perch and swim bladder of Rohu at 45-78% efficiency. It was identified as type-I based on a high molecular weight (110kDa) and its ion-exchange elution profile. The collagen samples were enzymatically hydrolyzed and collagen hydrolysate (CH) was extracted with an efficiency of 0.67-0.74g/g of collagen. The CH samples displayed a molecular weight in the range of 8.2-9.7kDa and exhibited a higher abundance of charges resulting in higher solubility. The structural studies revealed that the CH peptides existed in polyproline-II helix and formed a mimic-triple helix in a wide range of pH. In neutral and alkaline pH, the mimic helices joined to form a hierarchical quasi-fibrillar network that was smaller than collagen fibrils but also more dynamic. The CH exhibited >95% degradation in 15h through simulated digestion. The CH were able to decrease peroxide formation by 84.5-98.9% in commercially available cod liver and almond oil and increased the shelf life of soya bean oil by a factor of 5 after 6 months of storage. The addition of CH to cultured cells quenched peroxide ions generatedin situand decreased stressor activity by a factor of 12. The reason behind the high efficacy of CH was deciphered to be the proximal charge stabilization by the quasi-fibrillar network, which allowed efficient peroxide quenching and long-term stability.
Nse5/6 is a negative regulator of the ATPase activity of the Smc5/6 complex
Authors: Hallett Stephen T. , Schellenberger Pascale , Zhou Lihong , Beuron Fabienne , Morris Ed , Murray Johanne M. , Oliver Antony W.
Published: February 2021

The multi-component Smc5/6 complex plays a critical role in the resolution of recombination intermediates formed during mitosis and meiosis, and in the cellular response to replication stress. Using recombinant proteins, we have reconstituted a series of definedS. cerevisiaeSMC5/6 complexes, visualised them by negative stain electron microscopy, and tested their ability to function as an ATPase. We find that only the six protein ‘holo-complex’ is capable of turning over ATP and that its activity is significantly increased by the addition of double-stranded DNA to reaction mixes. Furthermore, stimulation is wholly dependent on functional ATP-binding pockets in both Smc5 and Smc6. Importantly, we demonstrate that budding yeast Nse5/6 acts as a negative regulator of Smc5/6 ATPase activity, binding to the head-end of the complex to suppress turnover, irrespective of the DNA-bound status of the complex.
Crystal structures of two hydrazide derivatives of mefenamic acid, 3-(2,3-dimethylanilino)-N′-[(E)-(furan-2-yl)methylidene]benzohydrazide and N′-[(E)-benzylidene]-2-(2,3-dimethylanilino)benzohydrazide
Authors: Mohamed Shaaban K. , Mague Joel T. , Akkurt Mehmet , Albayati Mustafa R. , Elgarhy Sahar M. I. , Al-Taifi Elham A.
Published: February 2021

The conformation about the central benzene ring in the molecule of (I), C20H19N3O2, is partially determined by an intramolecular N—H...O hydrogen bond. In the crystal, chains parallel to the c axis are generated by intermolecular N—H...O hydrogen bonds with the chains assembled into a three-dimensional network structure by intermolecular C—H...O hydrogen bonds and C—H...π(ring) interactions. The molecule of (II), C22H21N3O, differs from (I) only in the substituent at the hydrazide N atom where a phenylmethylene moiety for (II) is present instead of a furanmethylene moiety for (I). Hence, molecules of (I) and (II) show similarities in their molecular and crystal structures. The conformation of the central portion of the molecule of (II) is also therefore partially determined by an intramolecular N—H...O hydrogen bond and intermolecular N—H...O hydrogen bonds form chains parallel to the c axis. Likewise, the chains are connected into a three-dimensional network by C—H...O hydrogen bonds and C—H...π(ring) interactions.
Bis[2,3-bis(pyridin-2-yl)pyrazine-κ2
N
2,N
3]palladium(II) dinitrate acetonitrile monosolvate
Authors: Ha Kwang
Published: February 2021

The title compound, [Pd(C14H10N4)2](NO3)2·CH3CN, consists of a cationic PdII complex, two anions and one lattice solvent molecule, all in general positions. In the complex, the PdII cation is four-coordinated in a slightly distorted square-planar geometry defined by the four N atoms of two bidentate 2,3-di-2-pyridylpyrazine ligands. The complex, anions and solvent molecule are linked by weak C—H...O intermolecular hydrogen bonds. In the crystal, the complex molecules are stacked in columns along the a axis.
The capital structure decision of Islamic and conventional banks: empirical evidence from Malaysia
Authors: Guizani Moncef , Ajmi Ahdi Noomen
Published: February 2021

Purpose

The purpose of this paper is to investigate how Islamic banks (IBs) and conventional banks (CBs) in Malaysia choose their capital structure and what are the most significant factors that affect their decisions regarding their capital structure.

Design/methodology/approach

This study applies the autoregressive distributed lag (ARDL) approach for a sample of 54 Banks listed on Malaysian stock market over the period 2010–2018.

Findings

The study findings show that the capital structure of IBs appears to be driven by similar factors to those previously found in the corporate finance literature. They also provide evidence of the existence of a long-run and short-run relationship between leverage and its main determinants for Islamic and CBs. However, the results show that various independent variables on the capital structure do exhibit different effects (in magnitude of the coefficient) among Islamic and CBs. Moreover, we find that IBs slowly adjust their capital structure toward the desired leverage ratio than CBs.

Research limitations/implications

This research contributes to the theory in re-validating capital structure theories on IBs. It helps understand the capital structure of IBs in comparison with CBs. If in conventional finance, the standard presiding decisions of an economic agent is optimizing the risk-return ratio, this standard is not the only or the primary decision criterion in the Islamic finance context where spiritual and theological considerations are taken into consideration.

Practical implications

This research can contribute to managers in understanding the choice of capital structure for IBs within the bound of Sharia requirement. Such an understanding provides managers with applied knowledge of determining their appropriate capital structure to compete locally and globally in which IBs operate.

Originality/value

This paper offers some insights on the determinants of capital structure by investigating Islamic and CBs. It explores the implication of relevant Islamic principles on capital structure. Moreover, it analyses the determinants of capital structure using ARDL method that permits to identify the short-run and long-run relationships between capital structure and its main determinants.
Understanding customer brand engagement in brand communities: an application of psychological ownership theory and congruity theory
Authors: Kumar Jitender
Published: February 2021

Purpose

The purpose of this study is the exploration of customer engagement with the brand and brand community (dual foci) inside online brand communities and to assess the simultaneous impact of dual foci of engagement in creating equity for the brand. The role of sense of community is explored as a moderator in influencing customer engagement.

Design/methodology/approach

The sample is composed of the members of Facebook-based brand communities. An internet survey of 833 subjects provides data to test the theoretical model with the help of structural equation modelling using AMOS 21.

Findings

The empirical investigation supports the proposed theory except for a few counterintuitive findings. Psychological ownership with the brand and the brand community has a direct effect on customer engagement with the brand and the brand community, respectively. A brand-based value-congruity has a direct effect on brand engagement; however, community-based value-congruity has an indirect effect on brand community engagement through brand community psychological ownership. The moderating effect of sense of community on engagement is also observed. Engagement with dual foci explained a substantial proportion of the variance in brand equity.

Research limitations/implications

A student sample, cross-sectional research design and a limited number of constructs in the nomological network to explore engagement in an online brand community constitute few limitations of this study. Customer engagement with dual foci has major implications for both the researchers and practitioners dealing with online brand communities.

Practical implications

To engage customers in online brand communities, dual foci should be the objective of management. A sense of ownership towards the brand and value-congruity with the brand should be aimed to engage customers with the brands; brand community psychological ownership and value-congruity with the community should be embraced by the firms to achieve brand community engagement. A high sense of community also needs to be promoted for strengthening dual foci engagement that further generates brand equity.

Originality/value

Customer brand engagement and brand community engagement had been studied separately in literature ignoring the fact that brand is theraison d’etreof the community. Taking a dual object engagement perspective, this study has charted out different routes of how to generate brand equity using online brand communities.
An indexing system for the relevance of academic production and research from digital repositories and metadata
Authors: Guerrero-Sosa Jared David Tadeo , Menéndez-Domínguez Víctor Hugo , Castellanos-Bolaños María Enriqueta
Published: February 2021

Purpose

This paper aims to propose a set of quantitative statistical indicators for measuring the scientific relevance of research groups and researchers, based on high-impact open-access digital production repositories.

Design/methodology/approach

An action research (AR) methodology is proposed in which research is associated with the practice; research informs practice and practice is responsible for informing research in a cooperative way. AR is divided into five phases, beginning with the definition of the problematic scenario and an analysis of the state of the art and ending with conducting tests and publishing the results.

Findings

The proposed indicators were used to characterise group and individual output in a major public university in south-eastern Mexico. University campuses hosting a large number of high-impact research groups. These indicators were very useful in generating information that confirmed specific assumptions about the scientific production of the university.

Research limitations/implications

The data used here were retrieved from Scopus and open access national repository of Mexico. It would be possible to use other data sources to calculate these indicators.

Practical implications

The system used to implement the proposed indicators is independent of any particular technological tool and is based on standards for metadata description and exchange, thus facilitating the easy integration of new elements for evaluation.

Social implications

Many organisations evaluate researchers according to specific criteria, one of which is the prestige of journals. Although the guidelines differ between evaluation bodies, relevance is measured based on elements that can be adapted and where some have greater weight than others, including the prestige of the journal, the degree of collaboration with other researchers and individual production, etc. The proposed indicators can be used by various entities to evaluate researchers and research groups. Each country has its own organisations that are responsible for evaluation, using various criteria based on the impact of the publications.

Originality/value

The proposed indicators assess based on the importance of the types of publications and the degree of collaborations. However, they can be adapted to other similar scenarios.
Application of metaheuristic algorithms in interval type-2 fractional order fuzzy TID controller for nonlinear level control process under actuator and system component faults*
Authors: Patel Himanshukumar R. , Shah Vipul A.
Published: February 2021

Purpose

The two-tank level control system is one of the real-world's second-order system (SOS) widely used as the process control in industries. It is normally operated under the Proportional integral and derivative (PID) feedback control loop. The conventional PID controller performance degrades significantly in the existence of modeling uncertainty, faults and process disturbances. To overcome these limitations, the paper suggests an interval type-2 fuzzy logic based Tilt-Integral-Derivative Controller (IT2TID) which is modified structure of PID controller.

Design/methodology/approach

In this paper, an optimization IT2TID controller design for the conical, noninteracting level control system is presented. Regarding to modern optimization context, the flower pollination algorithm (FPA), among the most coherent population-based metaheuristic optimization techniques is applied to search for the appropriate IT2FTID's and IT2FPID's parameters. The proposed FPA-based IT2FTID/IT2FPID design framework is considered as the constrained optimization problem. System responses obtained by the IT2FTID controller designed by the FPA will be differentiated with those acquired by the IT2FPID controller also designed by the FPA.

Findings

As the results, it was found that the IT2FTID can provide the very satisfactory tracking and regulating responses of the conical two-tank noninteracting level control system superior as compared to IT2FPID significantly under the actuator and system component faults. Additionally, statistical Z-test carried out for both the controllers and an effectiveness of the proposed IT2FTID controller is proven as compared to IT2FPID and existing passive fault tolerant controller in recent literature.

Originality/value

Application of new metaheuristic algorithm to optimize interval type-2 fractional order TID controller for nonlinear level control system with two type of faults. Also, proposed method will compare with other method and statistical analysis will be presented.
Role of supplier involvement and project leader in SNPD: a conceptual model and exploratory case study
Authors: Wang Yuan , Yang Jie
Published: February 2021

Purpose

This paper focusses on the factors to sustainable product development (SNPD) projects success. More specifically, it aims to explore and understand the role of supplier involvement (SI) within SNPD. Additionally, it investigates how effective project leaders can facilitate effective supplier involvement and enhance focal firm's ability to successfully carry out sustainable achievement in product development.

Design/methodology/approach

A theoretical framework among SI, SNPD, project leader's personality and leadership style has been established. Six interviews collected from different industries are used to further explore the relationship among SI, SNPD, leader's personality and leadership style.

Findings

The difficulties in managing suppliers, the timing and extent of supplier involvement, communication method and frequency, as well as supplier contribution and challenge in SNPD has been summarized. The interviews also confirmed that effective leaders who possess certain personality traits enable appropriate supplier involvement, promote prosperous SNPD and enhance the relationship between SI and SNPD performance by allowing individual members, teams and organizations to function well.

Originality/value

Sustainable new product development (SNPD) has been recognized as one of the key factors to achieve environmental and economic success. The paper explores the role of supplier involvement in SNPD project and emphasizes the role of project leaders in the process.
Dynamic managerial capabilities and sustainable market competencies: role of organisational climate
Authors: Mehta Ahmed Muneeb , Ali Syed Ahmad
Published: February 2021

Purpose

Managerial capabilities are one of the primary resources in every organisation that have peculiar strategic objectives to fulfil. The purpose of this paper is an effort to dig out how managerial cognition, human capital and social capital as underpinnings of dynamic managerial capabilities (both separate and composite) affect sustainable strategic market creation (SMC) in nascent industries. Moreover, this study unfolds the role of dynamic managerial capabilities (sensing, seizing and reconfiguring) as a key mechanism through which these underpinnings lead to SMC.

Design/methodology/approach

For this purpose, a sample of 497 respondents was collected from top and middle-level managers of insurance companies in Pakistan. Structural equation modelling was used to test a set of direct, indirect and moderation hypotheses.

Findings

Findings revealed that DMC underpinnings have a direct positive impact on marketing and research and development competence dimensions of SMC. Results also confirmed significant mediation paths and substantial moderation of aforementioned organisational climate factors between dynamic managerial capabilities (DMC) and its underpinnings.

Originality/value

It offers a first examination of the possible moderation impact of innovation, flexibility and outward focus between DMC and its underpinnings as essential organisational climate factors.
Optimal pricing model of car-sharing: market pricing or platform pricing
Authors: Liang Ling , Tian Lin , Xie Jiaping , Xu Jianhong , Zhang Weisi
Published: February 2021

Purpose

The car-sharing market has entered the mature stage, and consumers' demand shows a diversified increasing trend. This paper considers two modes of operation and two pricing strategies, which are business-to-consumer and consumer-to-consumer modes, market pricing and platform pricing. Under these conditions, the platform's revenue-sharing ratio will be different. The purpose of this paper is to explore this research question, and seeks an optimal pricing mechanism that can achieve a win–win situation between platform and automobile manufacturer in the two market modes.

Design/methodology/approach

The authors design different profit functions for platform under the two contexts. Of course, the platform's function is constrained to the manufacturer's function. By introducing a revenue-sharing contract a Stackelberg game model dominated by the platform is established and the equilibrium solutions under the two pricing models are derived.

Findings

The study found that even if only market pricing is executed, the scale of the car-sharing market will continue to expand. As the car-sharing market becomes more saturated, platform pricing is better for the automobile manufacturer; in most cases, the platform prefers platform pricing, but when the number of private cars is relatively small, if the cost of car operation and maintenance for the automobile manufacturer is lower or the revenue-sharing ratio of private cars is high, then market pricing will be more favorable to the platform.

Practical implications

With the cross-border integration of car service platforms and the automobile manufacturing industry, the key to achieving win–win cooperation and sustainable development in the car-sharing market will converge on the question of how to design a suitable pricing mechanism and revenue-sharing method.

Originality/value

Authors have determined how a car-sharing platform achieves a win–win order pricing strategy with the manufacturer and private car owners, respectively. And authors combined the supply chain revenue-sharing contract with the car-sharing market to explore the application of the revenue-sharing contract in the sharing economy.