bluuebunny/crossref_metadata_2025 huggingface dataset:
Fungal communities in sediments along a depth gradient in the Eastern Tropical Pacific
Authors: Rojas-Jimenez Keilor , Grossart Hans Peter , Cordes Erik , Cortés Jorge
Published: June 2020

Deep waters represent the largest biome on Earth and the largest ecosystem of Costa Rica. Fungi play a fundamental role in global biogeochemical cycling in marine sediments, yet, they remain little explored. We studied fungal diversity and community composition in several marine sediments from 16 locations sampled along a bathymetric gradient (from a depth of 380 to 3474 m) in two transects of about 1500 km length in the Eastern Tropical Pacific (ETP) of Costa Rica. Sequence analysis of the V7-V8 region of the 18S rRNA gene obtained from sediment cores revealed the presence of 787 fungal amplicon sequence variants (ASVs). On average, we detected a richness of 75 fungal ASVs per sample. Ascomycota represented the most abundant phylum with Saccharomycetes constituting the dominant class. Three ASVs accounted for ca. 63% of all fungal sequences: the yeastMetschnikowia(49.4%),Rhizophydium(6.9%), andCladosporium(6.7%). Although we distinguished a cluster dominated by yeasts and a second cluster dominated by filamentous fungi, we were unable to detect a strong effect of depth, temperature, salinity, dissolved oxygen, and pH on the composition of fungal communities. We highlight the need to understand further the ecological role of fungi in deep-sea ecosystems.
WNT6-ACC2-induced accumulation of triacylglycerol rich lipid droplets is exploited byM. tuberculosis
Authors: Brandenburg Julius , Marwitz Sebastian , Tazoll Simone C. , Waldow Franziska , Kalsdorf Barbara , Vierbuchen Tim , Scholzen Thomas , Gross Annette , Goldenbaum Svenja , Hölscher Alexandra , Hein Martina , Linnemann Lara , Reimann Maja , Kispert Andreas , Leitges Michael , Rupp Jan , Lange Christoph , Niemann Stefan , Behrends Jochen , Goldmann Torsten , Heine Holger , Schaible Ulrich E. , Hölscher Christoph , Schwudke Dominik , Reiling Norbert
Published: June 2020

In view of emerging drug-resistant tuberculosis, host directed therapies are urgently needed to improve treatment outcomes with currently available anti-tuberculosis therapies. One option is to interfere with the formation of lipid-laden “foamy” macrophages in the infected host. Here, we provide evidence that WNT6, a member of the evolutionary conserved WNT signaling pathway, promotes foam cell formation by regulating key lipid metabolic genes including acetyl-CoA carboxylase-2 (ACC2) during pulmonary TB. In addition, we demonstrate thatMycobacterium tuberculosis(Mtb) facilitates its intracellular growth and dissemination in the host by exploiting the WNT6-ACC2 pathway. Using genetic and pharmacological approaches, we show that lack of functional WNT6 or ACC2 significantly reduces intracellular TAG levels, Mtb growth and necrotic cell death of macrophages. In combination with the anti-TB drug isoniazid, pharmacological inhibition of ACC2 improved anti-mycobacterial treatmentin vitroandin vivo. Therefore, we propose the WNT6-ACC2 signaling pathway as a promising target for a host-directed therapy to reduce intracellular replication of Mtb by modulating neutral lipid metabolism.
Nfkbidis required for immunity and antibody responses toToxoplasma gondii
Authors: Souza Scott P. , Splitt Samantha D. , Alvarez Julia A. , Sanchez-Arcila Juan C. , Wilson Jessica N. , Wizzard Safuwra , Luo Zheng , Baumgarth Nicole , Jensen Kirk D.C.
Published: June 2020

Protective immunity to parasitic infections has been difficult to elicit by vaccines. Among parasites that evade vaccine-induced immunity isToxoplasma gondii, which causes lethal secondary infections in chronically infected mice. Here we report that unlike susceptible C57BL/6J mice, A/J mice were highly resistant to secondary infection. To identify correlates of immunity, we utilized forward genetics to identifyNfkbid, a nuclear regulator of NF-κB that is required for B cell activation and B-1 cell development.Nfkbid-null mice (bumble) did not generate parasite-specific IgM and lacked robust parasite-specific IgG, which correlated with defects in B-2 cell maturation and class-switch recombination. Though high-affinity antibodies were B-2 derived, transfer of B-1 cells partially rescued the immunity defects observed in bumble mice and were required for 100% vaccine efficacy in bone marrow chimeric mice. Immunity in resistant mice correlated with robust isotype class-switching in both B cell lineages, which can be fine-tuned byNfkbidgene expression. We propose a model whereby humoral immunity toT. gondiiis regulated byNfkbidand requires B-1 and B-2 cells for full protection.

AUTHOR SUMMARY

Eukaryotic parasitic diseases account for approximately one fifth of all childhood deaths, yet no highly protective vaccine exists for any human parasite. More research must be done to discover how to elicit protective vaccine-induced immunity to parasitic pathogens. We used an unbiased genetic screen to find key genes responsible for immunity to the eukaryotic parasiteToxoplasma gondii. Our screen foundNfkbid, a transcription factor regulator, which controls B cell activation and innate-like B-1 cell development. Mice withoutNfkbidwere not protected againstT. gondiiand were deficient at making antibodies against the parasite. Our survival studies of vaccinated mice with and without B-1 compartments found that B-1 cells improved survival, suggesting that B-1 cells act in conjunction with B-2 cells to provide vaccine-induced immunity.Nfkbidand other loci identified in our unbiased screen represent potential targets for vaccines to elicit protective immune responses against parasitic pathogens.
Protein Contact Map Denoising Using Generative Adversarial Networks
Authors: Venkata Subramaniya Sai Raghavendra Maddhuri , Terashi Genki , Jain Aashish , Kagaya Yuki , Kihara Daisuke
Published: June 2020

Protein residue-residue contact prediction from protein sequence information has undergone substantial improvement in the past few years, which has made it a critical driving force for building correct protein tertiary structure models. Improving accuracy of contact predictions has, therefore, become the forefront of protein structure prediction. Here, we show a novel contact map denoising method, ContactGAN, which uses Generative Adversarial Networks (GAN) to refine predicted protein contact maps. ContactGAN was able to make a consistent and significant improvement over predictions made by recent contact prediction methods when tested on two datasets including protein structure modeling targets in CASP13. ContactGAN will be a valuable addition in the structure prediction pipeline to achieve an extra gain in contact prediction accuracy.
Deep multitask ensemble classification of emergency medical call incidents combining multimodal data improves emergency medical dispatch
Authors: Ferri Pablo , Sáez Carlos , Félix-De Castro Antonio , Juan-Albarracín Javier , Blanes-Selva Vicent , Sánchez-Cuesta Purificación , García-Gómez Juan M
Published: June 2020

Objective

To develop a predictive model to aid non-clinical dispatchers to classify emergency medical call incidents by their life-threatening level (yes/no), admissible response delay (undelayable, minutes, hours, days) and emergency system jurisdiction (emergency system/primary care) in real time.

Materials

A total of 1 244 624 independent retrospective incidents from the Valencian emergency medical dispatch service in Spain from 2009 to 2012, comprising clinical features, demographics, circumstantial factors and free text dispatcher observations.

Methods

A deep multitask ensemble model integrating four subnetworks, composed in turn by multi-layer perceptron modules, bidirectional long short-term memory units and a bidirectional encoding representations from transformers module.

Results

The model showed a micro F1 score of 0.771 in life-threatening classification, 0.592 in response delay and 0.801 in jurisdiction, obtaining a performance increase of 13.2%, 16.4% and 4.5%, respectively, with regard to the current in-house triage protocol of the Valencian emergency medical dispatch service.

Discussion

The model captures information present in emergency medical calls not considered by the existing in-house triage protocol, but relevant to carry out incident classification. Besides, the results suggest that most of this information is present in the free text dispatcher observations.

Conclusion

To our knowledge, this study presents the development of the first deep learning model undertaking emergency medical call incidents classification. Its adoption in medical dispatch centers would potentially improve emergency dispatch processes, resulting in a positive impact in patient wellbeing and health services sustainability.
Hypoferremia predicts hospitalization and oxygen demand in COVID-19 patients
Authors: Hippchen Theresa , Altamura Sandro , Muckenthaler Martina U. , Merle Uta
Published: June 2020

Background

Iron metabolism might play a crucial role in cytokine release syndrome in COVID-19 patients. Therefore we assessed iron metabolism markers in COVID-19 patients for their ability to predict disease severity.

Methods

COVID-19 patients referred to the Heidelberg University Hospital were retrospectively analyzed. Patients were divided into outpatients (cohort A, n=204), inpatients (cohort B, n=81), and outpatients later admitted to hospital because of health deterioration (cohort C, n=23).

Results

Iron metabolism parameters were severely altered in patients of cohort B and C compared to cohort A. In multivariate regression analysis including age, gender, CRP and iron-related parameters only serum iron and ferritin were significantly associated with hospitalization. ROC analysis revealed an AUC for serum iron of 0.894 and an iron concentration <6µmol/l as the best cutoff-point predicting hospitalization with a sensitivity of 94.7% and a specificity of 67.9%. When stratifying inpatients in a low- and high oxygen demand group serum iron levels differed significantly between these two groups and showed a high negative correlation with the inflammatory parameters IL-6, procalcitonin, and CRP. Unexpectedly, serum iron levels poorly correlate with hepcidin.

Conclusion

We conclude that measurement of serum iron can help predicting the severity of COVID-19. The differences in serum iron availability observed between the low and high oxygen demand group suggest that disturbed iron metabolism likely plays a causal role in the pathophysiology leading to lung injury.

KEY POINTS

Iron metabolism parameters are severely altered in COVID-19 patients.

Measurement of serum iron can help predicting the severity of COVID-19.
SNP-based quantitative deconvolution of biological mixtures: application to the detection of cows with subclinical mastitis by whole-genome sequencing of tank milk
Authors: Coppieters Wouter , Karim Latifa , Georges Michel
Published: June 2020

Biological products of importance in food (e.g., milk) and medical (e.g., donor blood-derived products) sciences often correspond to mixtures of samples contributed by multiple individuals. Identifying which individuals contributed to the mixture and in what proportions may be of interest in several circumstances. We herein present a method that allows to do this by shallow whole-genome sequencing of the DNA in mixed samples from hundreds of donors. We show the efficacy of the approach for the detection of cows with subclinical mastitis by analysis of farms’ tank mixtures containing milk from as many as 500 cows.
Dynamic transcriptional and chromatin accessibility landscape of medaka embryogenesis
Authors: Li Yingshu , Liu Yongjie , Yang Hang , Zhang Ting , Naruse Kiyoshi , Tu Qiang
Published: June 2020

Medaka (Oryzias latipes) has become an important vertebrate model widely used in genetics, developmental biology, environmental sciences, and many other fields. A high-quality genome sequence and a variety of genetic tools are available for this model organism. However, existing genome annotation is still rudimentary, as it was mainly based on computational prediction and short-read RNA-seq data. Here we report a dynamic transcriptome landscape of medaka embryogenesis profiled by long-read RNA-seq, short-read RNA-seq, and ATAC-seq. By integrating these data sets, we constructed a much-improved gene model set including about 17,000 novel isoforms and identified 1600 transcription factors, 1100 long noncoding RNAs, and 150,000 potential cis-regulatory elements as well. Time-series data sets provided another dimension of information. With the expression dynamics of genes and accessibility dynamics of cis-regulatory elements, we investigated isoform switching, as well as regulatory logic between accessible elements and genes, during embryogenesis. We built a user-friendly medaka omics data portal to present these data sets. This resource provides the first comprehensive omics data sets of medaka embryogenesis. Ultimately, we term these three assays as the minimum ENCODE toolbox and propose the use of it as the initial and essential profiling genomic assays for model organisms that have limited data available. This work will be of great value for the research community using medaka as the model organism and many others as well.
Event marketing, movie consumers' willingness and box office revenue
Authors: Sun Lei , Zhai Xin , Yang Huiqin
Published: June 2020

Purpose

This research investigates the impacts of movie consumers' willingness, measured by the number of people who want to watch a movie, on the relationship between event marketing and box office revenue. This study aims to provide marketers with practical event marketing strategies and tactics to improve box office revenue.

Design/methodology/approach

Panel data was collected for 1,141 movies released in China from year 2014–2018 for a total of 12 weeks, spanning 4 weeks before and 8 weeks after release. The mediating effect of consumers' willingness on the relationship between event marketing and box office revenue was tested through a stepwise method and the generalized least squares method based on random effects.

Findings

Movie consumers' willingness mediates the effect of event marketing and box office revenue. Both movie consumers' willingness and box office revenue follow an inverted U-shaped distribution against the intensity of event marketing. From the second week before release to the first week after release, intensified event marketing enhances box office revenue. Various types and intensities of event marketing should be employed in different periods of time to increase the total box office revenue.

Research limitations/implications

This research ignores the costs of various types of event marketing for different movies. Future research could consider the cost-effectiveness of event marketing.

Practical implications

The findings of this paper provide meaningful insights on event marketing strategies for practitioners.

Originality/value

This study contributes to the field by verifying movie consumers' willingness as a mediator between event marketing and box office revenue. The study also provides empirical evidences on effective types and reasonable intensities of event marketing over the whole lifecycle of movies.
The effect of industry-specific networking behaviour on the internationalization performance of Czech SMEs
Authors: Srivastava Mohit , Tyll Ladislav
Published: June 2020

Purpose

This paper aims to develop a thorough understanding of industry-specific networking behaviour on the internationalization performance of Czech small and medium enterprises (SMEs).

Design/methodology/approach

The authors used a profile deviation-ideal profile methodology to explore the ideal networking behaviour profile of different industries. The authors argue that firms adhering to ideal profiles performed well in the international market, while firms deviating from the ideal profile performed poorly. Data were collected through an online questionnaire specifically targeted at Czech SME executives. The authors attempted to explore these issues by using four aspects of networking behaviour to test the ideal networking behaviour profile of five different industries (automotive, telecommunications, construction, audit and finance and transportation).

Findings

The authors have identified different ideal networking behaviour profile for three industries, which underpinned supported the hypothesis that each dimension of networking behaviour should be fine-tuned for each sector to achieve to attain maximum benefits and performance in the international market.

Originality/value

Although previous studies supported the role of networking behaviour in improving internationalization performance, multiple studies had also provided conflicting results on how networking affects different industries and it is unclear how and why networking affects these various industries differently. The authors believe that the results research provides empirical evidence in proving that different networking dimensions should be fine-tuned as per industry to achieve the highest performance in the international market. The authors believe that the findings broaden the current understanding of the role of networks in the internationalization. The authors believe that the findings extend the current understanding of the role of networks in the internationalization of SMEs.
Security behaviour of mobile financial service users
Authors: Dzidzah Esther , Owusu Kwateng Kwame , Asante Benjamin Kofi
Published: June 2020

Purpose

The inception of mobile financial services (MFSs) has positively provoked economic growth and productivity, nonetheless, it has pessimistically caused an upward surge in cybersecurity threat. Customers are progressively becoming conscious of some of the threat and several of them now shun away from some suspicious activities over the internet as a form of protection. This study aims to explore the factors that influence users’ to adopt security behaviour.

Design/methodology/approach

A synthesis of theories – Self-efficacy and technology threat avoidance theories – was used to examine the security behaviour of users of MFSs. Data was gathered from 530 students in Ghana using convenience sampling technique. Data analysis was carried out using descriptive statistics, inferential statistics and structural equation model.

Findings

Outcome of the investigation indicate that both mastery experience and verbal persuasion have substantial effect on the avoidance motivation of MFSs users. It was, however, found that emotional state and vicarious experience of users do not influence their avoidance motivation. Also, it was established that avoidance motivation is a positive prognosticator of avoidance behaviour.

Practical implications

Understanding the security behaviour of MFS users will help the operators to outline strategies to sustain the successes achieved.

Originality/value

Studies on user security behaviour are rare, especially in sub Saharan Africa, thus, this study will contribute to extant literature by adding a new dimension of user security behaviour.
Impact of website attributes on customer engagement in banking: a solicitation of stimulus-organism-response theory
Authors: Islam Jamid Ul , Shahid Shadma , Rasool Aaleya , Rahman Zillur , Khan Imran , Rather Raouf Ahmad
Published: June 2020

Purpose

This paper aims to investigate how banking websites can activate customer engagement (CE) to consequently enhance customer trust and retention.

Design/methodology/approach

Using an online survey, data were collected from 598 customers of various (public and private) banks in India. Structural equation modeling was used to analyze the data.

Findings

Results reveal that the key website attributes viz. website interactivity, website aesthetics, customization, ease of use and telepresence positively affect CE. The results also delineate positive associations between CE, customer trust and customer retention.

Research limitations/implications

This paper unravels that by strategically focusing on the relational dynamics of CE, banks can build trust and retain their most valuable stakeholders – the customers, thereby addressing the crucial strategic concerns of banking firms.

Originality/value

This research is the first to explore the effects of key website attributes on CE in the banking context. The undertaking of this study in an emerging economy adds further insight into CE literature by generalizing the applicability of CE studies across geographic contexts.
Measuring performance of government-supported drug warehouses using DEA to improve quality of drug distribution
Authors: Dixit Anuj , Routroy Srikanta , Dubey Sunil Kumar
Published: June 2020

Purpose

Drug warehouses (DWs) play a crucial role in drug distribution of government-supported healthcare supply chain as it controls both the cost and responsiveness of the logistics activities. The current study proposes a methodology using data envelopment analysis (DEA) to estimate the performance along different dimensions and was applied to 30 government-supported DWs.

Design/methodology/approach

This study employs DEA to evaluate the performance and relative technical efficiency of DWs. In this research, four inputs and six outputs are identified based on intensive literature review and discussion with all stakeholders of DWs. The inputs are warehouse storage capacity, temperature-controlled storage capacity, number of skilled employees and operational cost, while the outputs are fill rate, number of generic drugs, volume of drugs, consumption points, inventory turns ratio and time efficiency.

Findings

Results show that 30% DWs operate at the most productive scale size with 100% efficiency level while 47% DWs have a significant possibility for further enhancement in productive efficiency and 23% DWs should diminish their operational size to increase their productivity level. It was also found that achieving 100% operational productivity along warehouse space capacity needs significant effort, whereas other three inputs, namely temperature-controlled capacity, number of skilled employees and operational cost, require comparatively less effort. Similarly, it was observed that the performance along the fill rate and time efficiency is satisfactory, whereas the performance along other fours output variables (i.e. number of generic drugs, volume of drugs, consumption points and inventory turns ratio) needs to be improved.

Practical implications

The findings offer insights on the inputs and outputs that significantly contribute to efficiencies so that inefficient DWs can focus on these factors.

Originality/value

Although many issues related to DEA have been widely researched and reported, but no literature has been found for analysis of DWs in general and government-supported DWs specifically to find out efficiencies for supply chain performance improvement.
A review of the influence of political connections on management’s decision in non-US settings
Authors: Amara Ines , Khlif Hichem
Published: June 2020

Purpose

Given the interest in better understanding the economic effects of political connections, this paper aims to review empirical studies in the accounting and finance domain investigating the effects of firms’ political connections on management’s decision in non-US settings.

Design/methodology/approach

Key words used to search for relevant studies include “political connections” linked with “tax avoidance,” “earnings quality” “voluntary disclosure.” The authors consult several editorial sources including Elsevier, Electronic Journals Service EBSCO, Emerald, Springer, Palgrave Macmillan, Sage, Taylor & Francis and Wiley-Blackwell. The authors’ search yields 46 published studies since 2006.

Findings

The review reveals a prevalence of studies conducted in Asia. A narrative synthesis of empirical findings shows mixed effects of political connections on earnings management, as measured by accrual-based or real earnings management practices. Mixed evidence also exists for the association between political connections and reporting policy (e.g. corporate social responsibility reporting). The review also reveals that firms with political ties adopt an aggressive tax policy aimed at reducing effective tax rates and are more likely to choose a Big 4 auditor.

Originality/value

The review discusses the political connections literature focusing on studies outside of the USA and the effect of such connections on decision-making by management. It identifies some limitations of this literature and offers guidance for future research avenues. The synthesis suggests that political connections can adversely or beneficially impact management’s decisions depending on the legal, institutional and cultural characteristics prevailing in a particular setting.
Pricing supply chain option contracts: a bilevel programming approach
Authors: Trabelsi Abir , Matsukawa Hiroaki
Published: June 2020

Purpose

This paper considers an option contract in a two-stage supplier-retailer supply chain (SC) when market demand is stochastic. The problem is a Stackelberg game with the supplier as a leader. This research assumes demand information sharing. The purpose of this study is to determine the optimal pricing strategy of the supplier along with the optimal order strategy of the retailer in three option contract cases.

Design/methodology/approach

The paper model the option contract pricing problem as a bilevel problem. The problem is then solved using bilevel programing methods. After computing, the generated outcomes are compared to a benchmark (wholesale price contract) to evaluate the contract.

Findings

The results reveal that only one of the contract cases can arbitrarily allocate the SC profit. In both other cases, the Stackelberg supplier manages to earn the total SC profit. Further analysis of the first contract, show that from the supplier’s perspective, the first stage forecast inaccuracy is beneficial, whereas the demand uncertainty in the second stage is detrimental. This contracting strategy guarantees both players better outcomes compared to the wholesale price contract.

Originality/value

To the best of the authors’ knowledge, this research is the first that links the option contract literature to the bilevel programing literature. It also the first to solve the pricing problem of the commitment option contract with demand update where the retailer exercises the option before knowing the exact demand.
Modeling the hierarchical structure of secondhand clothing buying behavior antecedents of millennials
Authors: Medalla Maria Esther , Yamagishi Kafferine , Tiu Ann Myril , Tanaid Reciel Ann , Abellana Dharyll Prince Mariscal , Caballes Shirley Ann , Jabilles Eula Margareth , Himang Celbert , Bongo Miriam , Ocampo Lanndon
Published: June 2020

Purpose

Due to the growing dominance of the millennials in the secondhand clothing (SHC) market, it is crucial to understand the dynamics of their SHC buying behavior. Despite such significance, it has yet to be explored in the current literature. To address such a gap, this paper aims to explore the antecedents of the SHC buying behavior of millennials.

Design/methodology/approach

A purposive survey is conducted to establish relationships between the antecedents. As such, the interrelationships of the antecedents are modeled using the interpretative structural modeling (ISM) approach.

Findings

Results reveal that SHC antecedents exhibit several characteristics depending upon their characterization of being driving, dependence, linkage and autonomous variables.

Originality/value

This work pioneers the identification of SHC buying behavior antecedents specifically for the millennial market, as well as in the provision of a holistic analysis of the complex contextual relationships of these antecedents. The findings of this work provide insights that are crucial to the extant literature in developing theoretical frameworks and paradigms that help in understanding the dynamics of the SHC buying behavior. Moreover, such results are beneficial to marketing managers and practitioners in innovating their strategies to capture the millennial market better.
Ethical leadership and employee unethical pro-organizational behavior: a moderated mediation model of moral disengagement and coworker ethical behavior
Authors: Hsieh Hui-Hsien , Hsu Hao-Hsin , Kao Kuo-Yang , Wang Chih-Chieh
Published: June 2020

Purpose

The purpose of this study is to understand how ethical leadership and coworker ethical behavior will influence employee unethical pro-organizational behavior (UPB). In particular, the authors examine the mediating effect of moral disengagement on the relationship between ethical leadership and UPB and also investigate the moderating effect of coworker ethical behavior on the aforementioned effect.

Design/methodology/approach

Data were collected from 251 employee–coworker dyads from five organizations in Taiwan at two time points. Moderated mediation analysis was conducted to test the hypotheses.

Findings

The results show that moral disengagement mediates the relationship between ethical leadership and employee UPB. Moreover, the results show that coworker ethical behavior moderates the relationship between moral disengagement and employee UPB, as well as the mediated relationship between ethical leadership and employee UPB via moral disengagement. Specifically, both the moral disengagement–UPB relationship and the ethical leadership–moral disengagement–UPB relationship become weaker when coworker ethical behavior is high.

Practical implications

The results highlight the importance of creating an ethical work environment to get everyone behaving ethically in the workplace, because nurturing an ethical atmosphere in organizations will be useful in reducing the occurrence of UPB even for those who have high levels of moral disengagement.

Originality/value

This study shows that coworkers matter morally as much as leaders, demonstrating the importance of social influence from coworkers in organizations.
Short selling and dark pool volume
Authors: Boulton Thomas Jason , Braga-Alves Marcus V.
Published: June 2020

Purpose

Prior research posits that traders with short-lived information favor lit exchanges over dark pools due to execution certainty. This paper aims to focus on the relation between informed trading based on firm fundamentals and dark pool volume because the preferred venue for traders with longer-lived information is less certain.

Design/methodology/approach

The authors examine the effect of short interest, a proxy for informed traders with long-lived information, on dark pool volume using fixed effects, first difference and instrumental variable approaches. They examine the effect of dark pools on the profitability of long-lived information using market- and characteristic-adjusted returns.

Findings

The proportion of trading volume executed in dark pools is positively correlated with short interest. This result is stronger for stocks that suffer from greater uncertainty and stocks targeted by transient institutional investors. Short sellers profit substantially from their information as subsequent returns are lower for heavily shorted stocks with greater dark pool volume.

Research limitations/implications

In 2014, the Financial Industry Regulatory Authority began making trading data available for dark pools. Before that, only limited information was publicly available. The authors use that data to shed more light on dark pools activity.

Practical implications

The evidence presented in the paper helps inform the current discussion about the role and regulation of dark pools.

Originality/value

This is the first study to show that informed traders with long-lived information favor dark pools due to their opacity and the possibility of price improvement.
Influence of various sintering parameters and the temperature dependent scaling on the dynamic hysteresis behavior of Ba0.9Ca0.05Sr0.05T0.85Zr0.15O3 ceramics
Authors: Suresh P. , Mathiyalagan P. , Srikanth K.S.
Published: June 2020

Purpose

The article explores the effect of sintering temperature on the ferroelectric hysteresis behavior of the synthesized ceramic material Ba0.9Ca0.05Sr0.05T0.85Zr0.15O3 (BCSTZO). It describes how the sintering temperature and its holding time have effect on the polarization-electric field (P-E) loops which is an important characteristic of a ferroelectric material. From the P-E loops obtained, various representative parameters like remnant polarization and coercive field values were extracted and scaling results were systematically established using them.

Design/methodology/approach

The present article describes the establishment of scaling relations for coercive field (Ec), remnant polarization (Pr) and back switching polarization (Pbc) as a function of temperature which have been obtained from P-E loops sintered at various temperature and time. This is because sintering temperature plays a pivotal role in determining the hysteresis parameters.

Findings

The temperature dependent scaling of Ec and Pr at sintering temperature of 1400, 1425, 1450 and 1475 °C yields EcαT0.40, EcαT0.80, EcαT0.47, EcαT0.29 and PrαT−1.72, PrαT−1.55, PrαT−1.72, PrαT−1.69 respectively. Further the scaling relations for the samples sintered at 1450 °C at different time interval of 3, 4, 5 and 6 h was also established to bring the effect of sintering in switching the ferroelectric hysteresis parameters.

Originality/value

The findings of this work will prove beneficial for the researchers working in optimization of sintering parameters and will benefit researchers selecting best material among the fabricated samples for further property enhancement. The optimized sample could be explored for multifunctional applications ranging from pyroelectric voltage to piezoelectric energy harvesting. In addition to this, the scaling results help to understand the nature of ferroelectric parameters with sintering. This may open up new avenues for studying the scaling behavior of dynamic hysteresis in synthesized material by focusing on hysteresis area as a function of applied electric fields, frequency and temperature. This reason owes to the fact that electric field and frequency are important parameters for a number of applications like sensor, transducers and medical applications.
MoS2-SiO2/EG hybrid nanofluid transport in a rotating channel under the influence of a strong magnetic dipole (Hall effect)
Authors: Mahato N. , Banerjee S.M. , Jana R.N. , Das S.
Published: June 2020

Purpose

The article focuses on the magnetohydrodynamic (MHD) convective flow of MoS2-SiO2 /ethylene glycol (EG) hybrid nanofluid. The effectiveness of Hall current, periodically heating wall and shape factor of nanoparticles on the magnetized flow of hybrid nanocomposite molybdenum disulfide- silicon dioxide (MoS2-SiO2) suspended in ethylene glycol (EG) in a vertical rotating channel under the influence of strong magnetic dipole (Hall effect) and thermal radiation is assessed. One of the channel walls has an oscillatory temperature gradient. Four different shapes (i.e. brick, cylinder, platelet and blade) of nanoparticles disseminated in base fluid (EG) are considered for simulation of the flow.

Design/methodology/approach

The analytical solution of governing equations has been presented. Influences of emerging physical parameters on the velocity and temperature profiles, the shear stresses and the rate of heat transfer are pointed out and discussed via graphs and tables.

Findings

The analysis revealed that Hall parameter has suppressing behavior on the velocity profiles within the rotating channel. The impact of nanoparticle shape factor advances the temperature characteristics significantly in the rotating channel. Brick-shape nanoparticles put up relatively low-temperature distribution in the rotating channel. The Hall parameter reduces the amplitudes of the shear stresses at the channel wall. However, the radiation parameter enhances the amplitude of the rate of heat transfer at the channel wall.

Social implications

The important technical advantage of hybrid composition of nanoparticles as a drug carrier is its stability, high thermal conductivity, high load carrying capacity, etc. The proposed model may be beneficial in biomedical engineering, automobile parts, mineral and cleaning oils manufacturing, rubber and plastic industries.

Originality/value

To the best of our knowledge, there is little or no report on the aspects of assessment of the effectiveness of Hall current and nanoparticle shape factor on an MHD flow and heat transfer of an electrically conducting MoS2-SiO2/EG ethylene glycol-based hybrid nanofluid confined in a vertical channel with periodically varying wall temperature subject to a rotating frame. The present work furnishes a robust benchmark for the dynamics of nanofluids.
Orthotropic anisotropy: on contributions of elasticity parameters to a difference in quasi‐P‐wave‐squared velocities resulted from propagation in two orthogonal symmetry planes
Authors: Adamus Filip P.
Published: June 2020

We investigate the dependence of quasi P‐wave phase velocity propagating in orthotropic media on particular elasticity parameters. Specifically, due to mathematical facilitation, we consider the squared‐velocity difference, , resulted from propagation in two mutually perpendicular symmetry planes. In the context of the effective medium theory, may be viewed as a parameter evaluating the influence of cracks – embedded in the background medium – parallel to one or both aforementioned planes. Our investigation is both theoretical and numerical. Based on Christoffel's equations, we propose two accurate approximations of . Due to them, we interpret the aforementioned squared‐velocity difference as being twice more dependent on , than on . To describe the magnitude of the dependence, we consider the proportions between the partial derivatives of . Further, it occurs that is influenced by the ratio of vertically propagating quasi P‐wave to vertically propagating quasi S‐wave. Anomalously high might be caused by the low P/S ratio, which in turn can be an indicator of the presence of gas in natural fractures or aligned porosity. Also, we carry out numerical sensitivity study, according to which is approximately twice more dependent on than on , twice more sensitive to than to , and equally dependent on as on . The dependence on and can be neglected, especially for small phase angles. We verify the approximations and perform the sensitivity study, using eight examples of the elasticity tensors.
Arbitrary‐order Taylor series expansion‐based viscoacoustic wavefield simulation in 3D vertical transversely isotropic media
Authors: Zhang Yabing , Liu Yang , Xu Shigang
Published: June 2020

Taking the anisotropy of velocity and attenuation into account, we investigate the wavefield simulation of viscoacoustic waves in 3D vertical transversely isotropic attenuating media. The viscoacoustic wave equations with the decoupled amplitude attenuation and phase dispersion are derived from the fractional Laplacian operator and using the acoustic approximation. With respect to the spatially variable fractional Laplacian operator in the formulation, we develop an effective algorithm to realize the viscoacoustic wavefield extrapolation by using the arbitrary‐order Taylor series expansion. Based on the approximation, the mixed‐domain fractional Laplacian operators are decoupled from the wavenumbers and fractional orders. Thus, the viscoacoustic wave propagation can be conveniently implemented by using a generalized pseudospectral method. In addition, we perform the accuracy and efficiency analyses among first‐, second‐ and third‐order Taylor series expansion pseudospectral methods with different quality factors. Considering both the accuracy and computational cost, the second‐order Taylor series expansion pseudospectral method can generally satisfy the requirements for most attenuating media. Numerical modelling examples not only illustrate that our decoupled viscoacoustic wave equations can effectively describe the attenuating property of the medium, but also demonstrate the accuracy and the high robustness of our proposed schemes.
Predators drive community reorganization during experimental range shifts
Authors: Jones Natalie T. , Symons Celia C. , Cavalheri Hamanda , Pedroza‐Ramos Adriana , Shurin Jonathan B.
Published: June 2020

Increased global temperatures caused by climate change are causing species to shift their ranges and colonize new sites, creating novel assemblages that have historically not interacted. Species interactions play a central role in the response of ecosystems to climate change, but the role of trophic interactions in facilitating or preventing range expansions is largely unknown.

The goal of our study was to understand how predators influence the ability of range‐shifting prey to successfully establish in newly available habitat following climate warming. We hypothesized that fish predation facilitates the establishment of colonizing zooplankton populations, because fish preferentially consume larger species that would otherwise competitively exclude smaller‐bodied colonists.

We conducted a mesocosm experiment with zooplankton communities and their fish predators from lakes of the Sierra Nevada Mountains in California, USA. We tested the effect of fish predation on the establishment and persistence of a zooplankton community when introduced in the presence of higher‐ and lower‐elevation communities at two experimental temperatures in field mesocosms.

We found that predators reduce the abundance of larger‐bodied residents from the alpine and facilitate the establishment of new lower‐elevation species. In addition, fish predation and warming independently reduced the average body size of zooplankton by up to 30%. This reduction in body size offset the direct effect of warming‐induced increases in population growth rates, leading to no net change in zooplankton biomass or trophic cascade strength.

We found support for a shift to smaller species with climate change through two mechanisms: (a) the direct effects of warming on developmental rates and (b) size‐selective predation that altered the identity of species’ that could colonize new higher elevation habitat. Our results suggest that predators can amplify the rate of range shifts by consuming larger‐bodied residents and facilitating the establishment of new species. However, the effects of climate warming were dampened by reducing the average body size of community members, leading to no net change in ecosystem function, despite higher growth rates. This work suggests that trophic interactions play a role in the reorganization of regional communities under climate warming.
Changes in age‐structure over four decades were a key determinant of population growth rate in a long‐lived mammal
Authors: Jackson John , Mar Khyne U. , Htut Win , Childs Dylan Z. , Lummaa Virpi
Published: June 2020

A changing environment directly influences birth and mortality rates, and thus population growth rates. However, population growth rates in the short term are also influenced by population age‐structure. Despite its importance, the contribution of age‐structure to population growth rates has rarely been explored empirically in wildlife populations with long‐term demographic data.

Here we assessed how changes in age‐structure influenced short‐term population dynamics in a semi‐captive population of Asian elephantsElephas maximus.

We addressed this question using a demographic dataset of female Asian elephants from timber camps in Myanmar spanning 45 years (1970–2014). First, we explored temporal variation in age‐structure. Then, using annual matrix population models, we used a retrospective approach to assess the contributions of age‐structure and vital rates to short‐term population growth rates with respect to the average environment.

Age‐structure was highly variable over the study period, with large proportions of juveniles in the years 1970 and 1985, and made a substantial contribution to annual population growth rate deviations. High adult birth rates between 1970 and 1980 would have resulted in large positive population growth rates, but these were prevented by a low proportion of reproductive‐aged females.

We highlight that an understanding of both age‐specific vital rates and age‐structure is needed to assess short‐term population dynamics. Furthermore, this example from a human‐managed system suggests that the importance of age‐structure may be accentuated in populations experiencing human disturbance where age‐structure is unstable, such as those in captivity or for endangered species. Ultimately, changes to the environment drive population dynamics by influencing birth and mortality rates, but understanding demographic structure is crucial for assessing population growth.
Using genomics to design and evaluate the performance of underwater forest restoration
Authors: Wood Georgina , Marzinelli Ezequiel M. , Vergés Adriana , Campbell Alexandra H. , Steinberg Peter D. , Coleman Melinda A.
Published: June 2020

Restoration is an emerging intervention to reverse the degradation and loss of marine habitat‐formers and the ecosystem services they underpin. Current best practice seeks to restore populations by transplanting donor individuals chosen to replicate genetic diversity and structure of extant, nearby populations. However, genetic characteristics are rarely empirically examined across generations, despite their potential role in influencing restoration success.

We used genomics to design a restoration program for lost underwater forests of Phyllospora comosa, a dominant forest‐forming macroalga that went locally extinct from reefs off Sydney, Australia. Population genetic diversity and structure of nearby extant populations informed choice of donor sites. We tested whether donor provenance influenced adult transplant survival, condition (via metrics of epibiosis) and the genetic characteristics of recruits at restoration sites.

Extant populations of Phyllospora within a 100‐km radius of Sydney comprised three distinct genetic clusters with similar levels of genetic diversity. We transplanted reproductive adults from two of these sites, with the aim of restoring five Phyllospora forests with levels of genetic structure and diversity similar to donor populations.

Donor provenance influenced survival and condition of transplanted adults and recruitment levels varied significantly among restoration sites. Yet, recruitment was rapid and genetic diversity and structure of the F1 generation resembled extant populations. This likely occurred because transplanted individuals reproduced synchronously and rapidly post‐transplantation, prior to mortality of adult donor transplants.

Synthesis and applications. As restoration and the need to ‘future‐proof’ marine ecosystems increase globally, it will be critical to understand and harness the role of donor provenance, genetic diversity and structure in restoration success. By incorporating ecological and genomic data into restoration design and assessment, this study demonstrates that evidence‐based selection of macroalgal donors can result in F1 generation recruits with similar levels of genetic diversity and structure as extant populations, despite an effect of provenance on transplant survival and condition. This study also highlights the need for ongoing refinement of transplantation techniques to ensure future recruitment success.