bluuebunny/crossref_metadata_2025 huggingface dataset:
Sulfide toxicity as key control on anaerobic oxidation of methane in eutrophic coastal sediments
Authors: Martins Paula Dalcin , de Monlevad João P. R. C. , Lenstra Wytze K. , Wallenius Anna J. , Echeveste Medrano Maider J. , Hermans Martijn , Slomp Caroline P. , Welte Cornelia U. , Jetten Mike S. M. , van Helmond Niels A.G.M.
Published: February 2022

Coastal zones account for significant global marine methane emissions to the atmosphere. In coastal ecosystems, the tight balance between microbial methane production and oxidation in sediments prevents most methane from escaping to the water column. Anthropogenic activities, causing eutrophication and bottom water deoxygenation, could disrupt this balance in the microbial methane cycle and lead to increased methane release from coastal sediments. Here, we combined microbiological and biogeochemical analyses of sediments from three sites along a bottom water redox gradient (oxic-hypoxic-euxinic) in the eutrophic Stockholm Archipelago to investigate the impact of anthropogenically-induced redox shifts on microbial methane cycling. At both the hypoxic and euxinic site, sediments displayed a stronger depletion of terminal electron acceptors at depth and a shoaling of the sulfate-methane transition zone in comparison to the oxic site. Porewater methane and sulfide concentrations and potential methane production rates were also higher at the hypoxic and euxinic site. Analyses of metagenome-assembled genomes and 16S rRNA gene profiling indicated that methanogens became more abundant at the hypoxic and euxinic site, while anaerobic methane-oxidizing archaea (ANME), present in low coverage at the oxic site, increased at the hypoxic site but virtually disappeared at the euxinic site. A 98% complete genome of an ANME-2b Ca. Methanomarinus archaeon had genes encoding a complete reverse methanogenesis pathway, several multiheme cytochromes, and a sulfite reductase predicted to detoxify sulfite. Based on these results, we infer that sulfide exposure at the euxinic site led to toxicity in ANME, which, despite the abundance of substrates at this site, could no longer thrive. These mechanistic insights imply that the development of euxinia, driven by eutrophication, could disrupt the coastal methane biofilter, leading to increased benthic methane release and potential increased methane emissions from coastal zones to the atmosphere.
Causes, temporal trends and the effects of urbanisation on admissions of wild raptors to rehabilitation centres in England and Wales
Authors: Panter Connor T. , Allen Simon , Backhouse Nikki , Mullineaux Elizabeth , Rose Carole-Ann , Amar Arjun
Published: February 2022

Data from wildlife rehabilitation centres can provide on-the-ground records of causes of raptor morbidity and mortality, allowing threat patterns to be explored throughout time and space. We provide an overview of native raptor admissions to four wildlife rehabilitation centres (WRCs) in England and Wales, quantifying the main causes of morbidity and mortality, trends over time and whether certain causes were more common in more urbanised areas between 2001-2019. Throughout the study period 14 raptor species were admitted totalling 3305 admission records. The Common Buzzard (Buteo buteo;31%) and Tawny Owl (Strix aluco; 29%) were most numerous. Relative to the proportion of breeding individuals in Britain & Ireland, Peregrine Falcons (Falco peregrinus), Little Owls (Athene noctua) and Western Barn Owls (Tyto alba) were over-represented in the admissions data by 103%, 73% and 69%, respectively. Contrastingly Northern Long-eared Owls (Asio otus), Western Marsh Harriers (Circus aeruginosus) and Merlin (Falco columbarius) were under-represented by 187%, 163% and 126%, respectively. Across all species, vehicle collisions were the most frequent anthropogenic admission cause (22%) and orphaned young birds (10%) were most frequent natural admission cause. Mortality rate was highest for infection/parasite admissions (90%), whereas orphaned birds experienced lowest mortality rates (16%). For one WRC, there was a notable decline in admissions over the study period. Red Kite (Milvus milvus) admissions increased over time, whereas Common Buzzard and Common Kestrel admissions declined. There were significant declines in the relative proportion of persecution and metabolic admissions, and an increase in orphaned young birds. Urban areas were positively associated with persecution, building collisions and unknown trauma admissions, whereas vehicle collisions were associated with more rural areas. Many threats persist for raptors in England and Wales, however, have not changed substantially over the past two decades. Threats associated with urban areas, such as building collisions, may increase over time in line with human population growth and subsequent urban expansion.
Morphological profiling of environmental chemicals enables efficient and untargeted exploration of combination effects
Authors: Rietdijk Jonne , Aggarwal Tanya , Georgieva Polina , Lapins Maris , Carreras-Puigvert Jordi , Spjuth Ola
Published: February 2022

Environmental chemicals are commonly studied one at a time, and there is a need to advance our understanding of the effect of exposure to their combinations. Here we apply high-content microscopy imaging of cells stained with multiplexed dyes (Cell Painting) to profile the effects of Cetyltrimethylammonium bromide (CTAB), Bisphenol A (BPA), and Dibutyltin dilaurate (DBTDL) exposure on four human cell lines; both individually and in all combinations. We show that morphological features can be used with multivariate data analysis to discern between exposures from individual compounds, concentrations, and combinations. CTAB and DBTDL induced concentration-dependent morphological changes across the four cell lines, and BPA exacerbated morphological effects when combined with CTAB and DBTDL. Combined exposure to CTAB and BPA induced changes on the ER, Golgi apparatus, nucleoli and cytoplasmic RNA in one of the cell lines. Different responses between cell lines indicate that multiple cell types are needed when assessing combination effects. The rapid and relatively low-cost experiments combined with high information content makes Cell Painting an attractive methodology for future studies of combination effects. All data in the study is made publicly available on Figshare.

Highlights

Assessment of combination effects of BPA, CTAB and DBTDL on four human cell lines

Morphological profiling/Cell Painting captures dose and combination dependent effects

BPA exacerbated morphological effects when combined with CTAB and DBTDL.

Cell models of diverse origin are needed when profiling environmental chemicals
Feasibility of enhancing carbon sequestration and stock capacity in temperate and boreal European forests via changes to management regimes
Authors: Dalmonech D. , Marano G. , Amthor J.S. , Cescatti A. , Lindner M. , Trotta C. , Collalti A.
Published: February 2022

Forest management practices might act as nature-based methods to remove CO2from the atmosphere and slow anthropogenic climate change and thus support an EU forest-based climate change mitigation strategy. However, the extent to which diversified management actions could lead to quantitatively important changes in carbon sequestration and stocking capacity at the tree level remains to be thoroughly assessed. To that end, we used a state-of-the-science bio-geochemically based forest growth model to simulate effects of multiple forest management scenarios on net primary productivity (NPP) and potential carbon woody stocks (pCWS) under twenty scenarios of climate change in a suite of observed and virtual forest stands in temperate and boreal European forests. Previous modelling experiments indicated that the capacity of forests to assimilate and store atmospheric CO2in woody biomass is already being attained under business-as-usual forest management practices across a range of climate change scenarios. Nevertheless, we find that on the long-term, with increasing atmospheric CO2concentration and warming, managed forests show both higher productivity capacity and a larger potential pool size of stored carbon than unmanaged forests as long as thinning and tree harvesting are of moderate intensity.
Chemometrics-based evaluation on effect of sonication, contact time and solvent-to-solid ratio on total phenolics and flavonoids, fatty acids and antibacterial potency of Carica papaya seed against S. enteritidis, B. cereus, V. vulnificus and P. mirabilis
Authors: Abdullah Sani Muhamad Shirwan
Published: February 2022

This study was aimed on extraction optimization of antibacterial agent from Carica papaya seed against S. enteritidis, B. cereus, V. vulnificus and P. mirabilis as affected by sonication-assisted extraction (SAE), contact time (CT) and solid-to-solvent ratio (SSR). The principal component analysis (PCA) and individual evaluation approaches identified that no SAE, 8 CT and 1:10 SSR was the best treatment with the highest antibacterial potency. The PCA identified no SAE, 8 CT, and 1:5 SSR as the second-beat treatment. The yield, total phenolic compound (TPC), C18:1n9t and C16:1 fatty acids (FAs) in no SAE, 8 CT and 1:10 SSR treatment inhibited the growth of B. cereus, V. vulnificus and P. mirabilis while C21:0 and C15:0 in 30 min SAE, 8 CT and 1:2 SSR inhibited the S. enteritidis growth. The yield, TPC, C18:1n9t and C16:1 FAs, and C6:0 and C24:1n9, C20:1, C4:0 and C20:0 FAs had antagonistic effects on B. cereus, V. vulnificus and P. mirabilis growths. The C21:0, C15:0, C6:0 and C13:0, and C23:0, C20:0 and C11:0 FAs had antagonistic effects on S. enteritidis growth. The PCA also denoted that the MIC50 and MIC0 had a higher variation than MIC; hence, the former variables were better to use in PCA.
A pore-forming β-trefoil lectin with specificity for the tumor-related glycosphingolipid Gb3
Authors: Notova Simona , Bonnardel François , Rosato Francesca , Siukstaite Lina , Schwaiger Jessica , Bovin Nicolai , Varrot Annabelle , Römer Winfried , Lisacek Frédérique , Imberty Anne
Published: February 2022

Lectins are efficient multivalent glycan receptors, deciphering the glyco-code on cell surfaces. The β-trefoil fold, characterized by three lobe-shaped repeats, is adopted by several classes of lectins, often associated with other domains having enzymatic or toxic activity. Based on the UniLectin3D database classification, the sequence signature of trefoil lobes was defined and used to predict 44714 lectins from 4497 species. Among them, SaroL-1 from the lower eukaryote Salpingoeca rosetta was predicted to contain both β-trefoil and aerolysin-like pore-forming domain. Recombinant SaroL-1 binds to galactose and derivatives, with a stronger affinity for cancer-related α-galactosylated epitopes such as glycosphingolipid Gb3 embedded in giant unilamellar vesicles or cell membranes. Crystal structures in complex with Gb3 trisaccharide and GalNAc show similarity with pore-forming toxins. Recognition of the αGal epitope on glycolipids was necessary for hemolysis of rabbit erythrocytes and toxicity on cancer cells through carbohydrate-dependent pore-formation.
Structural basis of human IL-18 sequestration by the decoy receptor IL-18 binding protein (IL-18BP) in inflammation and tumor immunity
Authors: Detry Sammy , Andries Julie , Bloch Yehudi , Gabay Cem , Clancy Danielle , Savvides Savvas N.
Published: February 2022

Human Interleukin-18 (IL-18) is an omnipresent pro-inflammatory cytokine of the IL-1 family with central roles in autoimmune and inflammatory diseases, and serving as a staple biomarker in the evaluation of inflammation in physiology and disease, including the inflammatory phase in COVID-19. The sequestration of IL-18 by its soluble decoy receptor IL-18 Binding Protein (IL-18BP) is critical to the regulation of IL-18 activity. Since an imbalance in expression and circulating levels of IL-18 is associated with disease, structural insights into how IL-18BP outcompetes binding of IL-18 by its cognate cell-surface receptors would be highly desirable. However, the structure of human IL-18BP in complex with IL-18 had remained elusive. Here, we elucidate the sequestration mechanism of human IL-18 mediated by IL-18BP based on the crystal structure of the IL-18:IL-18BP complex. These detailed structural snapshots reveal the interaction landscape leading to the ultra-high affinity of IL-18BP towards IL-18 and identify substantial differences with respect to previously characterized complexes of IL-18 with IL-18BP of viral origin. Furthermore, our structure captured a fortuitous higher-order assembly between IL-18 and IL-18BP coordinated by a disulfide-bond distal to the binding surface connecting IL-18 and IL-18BP molecule from different complexes, resulting in a novel complex with 2:2 stoichiometry. This tetrapartite assembly was found to restrain IL-18 activity more effectively than the canonical 1:1 complex. Collectively, our findings will provide a framework for innovative structure-driven therapeutic strategies and further functional interrogation of IL-18 in physiology and disease.

Significance statement

Elevated levels of interleukin-18 (IL-18) have long been implicated in numerous inflammatory diseases while also displaying potent anti-tumoral activities. Recent research on COVID-19 has now underscored the role of IL-18 and IL-18 binding protein (IL-18BP), a soluble receptor serving to regulate IL-18 activity, as key players in viral immunity and as promising biomarkers and predictors of disease severity. In this work, we present detailed structural insights into how human IL-18 and IL-18BP interact thereby completing the structural repertoire of IL-18 in complex with its cognate human receptors and viral decoy receptors. Our findings will support structure-based efforts to either disrupt or enhance the interactions of IL-18 with its cognate receptors for therapeutic purposes.
Fentanyl reinstatement to discriminative cues after conflict in sign- and goal-tracking rats
Authors: Martin David A. , Keefer Sara E. , Calu Donna J.
Published: February 2022

Rationale

Discriminative stimuli (DS) are cues that predict reward availability. DS are resistant to extinction and motivate drug seeking even after long periods of abstinence. Previous studies have demonstrated that sign tracking (ST) and goal tracking (GT) individual differences in Pavlovian approach to food cues predict distinct vulnerabilities to CS and DS reinstatement of cocaine seeking, respectively. Compared to goal-trackers, sign-trackers show heightened CS relapse even after electric barrier induced abstinence. We do not know whether DS relapse persists after electric barrier induced abstinence, or whether tracking-related relapse vulnerabilities generalize to models of opioid relapse.

Objectives

We sought to determine if DS-induced reinstatement of fentanyl seeking persists in the presence of reduced adverse consequences after electric barrier-induced abstinence. We also aimed to determine whether tracking differences predict the magnitude of DS-induced reinstatement of fentanyl seeking after electric barrier-induced abstinence.

Methods

First we used Pavlovian lever autoshaping (PLA) training to determine sign-, goal- and intermediate tracking groups in male and female Sprague Dawley rats. We then trained rats in a DS model of intermittent fentanyl self-administration, and extinguished drug seeking by imposing an electric barrier of increasing intensity. We then measured the level of DS-induced reinstatement in the presence of a reduced electric barrier intensity.

Results

We report that DS produce large increases in fentanyl seeking after electric barrier induced abstinence. Contrary to our expectations, the magnitude of the DS induced reinstatement effect was not related to tracking group.

Conclusions

Discriminative stimuli powerfully motivate opioid seeking, despite continued aversive consequences. Individual differences in Pavlovian approach do not predict the level of DS reinstatement to fentanyl seeking after conflict induced abstinence.
OzTracs: Optical Osmolality Reporters Engineered from Mechanosensitive Ion Channels
Authors: Kleist Thomas J. , Lin I Winnie , Xu Sophia , Maksaev Grigory , Sadoine Mayuri , Haswell Elizabeth S. , Frommer Wolf B. , Wudick Michael M.
Published: February 2022

Interactions between physical forces and membrane proteins underpin many forms of environmental sensation and acclimation. Microbes survive sudden osmotic stresses with the help of mechanically gated ion channels and osmolyte transporters. Plant mechanosensitive ion channels have been shown to function in defense signaling. Here, we engineered genetically encoded osmolality sensors (OzTracs) by fusing green fluorescent protein spectral variants to the mechanosensitive ion channels MscL from E. coli or MSL10 from A. thaliana. When expressed in yeast cells, OzTrac sensors reported osmolality changes as a proportional change in emission ratio of the two fluorescent protein domains. Live-cell imaging revealed accumulation of fluorescent sensors in internal aggregates presumably derived from the endomembrane system. Thus, OzTrac sensors serve as osmolality-dependent reporters through an indirect mechanism, such as effects on molecular crowding or fluorophore solvation.
Exploring the Frame Effect
Authors: Cavanagh Patrick , Anstis Stuart , Lisi Matteo , Wexler Mark , Maechler Marvin , ’t Hart Marius , Shams-Ahmar Mohammad , Saleki Sharif
Published: February 2022

Probes flashed within a moving frame are dramatically displaced (Özkan et al, 2021; Wong &Mack, 1981). The effect is much larger than that seen on static or moving probes (induced motion, Duncker, 1929; Wallach et al, 1978). These flashed probes are often perceived with the separation they have in frame coordinates — a 100% effect. Here we explore this frame effect on flashed tests with several versions of the standard stimulus. We find that the frame effect holds for smoothly or abruptly displacing frames, even when the frame changed shape or orientation between the endpoints of its travel. The path could be non-linear, even circular. The effect was driven by perceived not physical motion. When there were competing overlapping frames, the effect was determined by which frame was attended. There were a number of constraints that limited the effect. A static anchor near the flashes suppressed the effect but an extended static texture did not. If the probes were continuous rather than flashed, the effect was abolished. The observational reports of 30 online participants suggest that the frame effect is robust to many variations in its shape and path and leads to a perception of flashed tests in their locations relative to the frame as if the frame were stationary. Our results highlight the role of frame continuity and of the grouping of the flashes with the frame in generating the frame effect.
SOCIALITY, COMMUNITIES AND MORPHOLOGICAL FEATURES OF ANTS FROM MID-CRETACEOUS BURMESE AMBER
Authors: Perfilieva K.S.
Published: February 2022

We consider morphological diversity of ants from mid-Cretaceous Burmese amber. An eco-ethological hypothesis concerning its origin and features of Mesozoic and Cenozoic ant communities is proposed. It appears that some morphological features of representatives of the stem taxa allow us to speak about the absence of effective communication and, subsequently, group foraging in these ants. Therefore, the diversity of primitive Cretaceous ants, as predators, reflects their food specialization according to types of prey, on condition of their social lifestyle, that results in division of the ecological space among ant species into ecological niches. The occurrence of both effective communication and group foraging (mobilization) in the crown ant taxa, as crucial adaptation, has permitted them to exceed the bounds of niches of specialized predators, since type and size of prey are not strictly correlated to size of an ant and its mandibles; it also has given a chance to maintain large colonies. Due to this, myrmecocomplexes of modern ants are arranged on the principle of colonies dominance rather than the principle of division of ecological niches, like Mesozoic.
The regulatory protein ChuP connects heme and siderophore-mediated iron acquisition systems required for Chromobacterium violaceum virulence
Authors: de Lima Vinicius M. , Batista Bianca B. , Silva Neto José F. da
Published: February 2022

Chromobacterium violaceum is an environmental Gram-negative beta-proteobacterium that causes systemic infections in humans. C. violaceum uses siderophore-based iron acquisition systems to overcome the host-imposed iron limitation, but its capacity to use other iron sources is unknown. In this work, we characterized ChuPRSTUV as a heme utilization system employed by C. violaceum to explore an important iron reservoir in mammalian hosts, free heme and hemoproteins. We demonstrate that the chuPRSTUV genes comprise a Fur-repressed operon that is expressed under iron limitation. The chu operon potentially encodes a small regulatory protein (ChuP), an outer membrane TonB-dependent receptor (ChuR), a heme degradation enzyme (ChuS), and an inner membrane ABC transporter (ChuTUV). Our nutrition growth experiments using C. violaceum chu deletion mutants revealed that, with the exception of chuS, all genes of the chu operon are required for heme and hemoglobin utilization in C. violaceum. The mutant strains without chuP displayed increased siderophore halos on CAS plate assays. Significantly, we demonstrate that ChuP connects heme and siderophore utilization by acting as a positive regulator of chuR and vbuA, which encode the TonB-dependent receptors for the uptake of heme (ChuR) and the siderophore viobactin (VbuA). Our data favor a model of ChuP as a heme-binding post-transcriptional regulator. Moreover, our virulence data in a mice model of acute infection demonstrate that C. violaceum uses both heme and siderophore for iron acquisition during infection, with a preference for siderophores over the Chu heme utilization system.
Sexual transmission of Anopheles gambiae densovirus (AgDNV) leads to disseminated infection in mated females
Authors: Werling Kristine L , Johnson Rebecca M. , Metz Hillery C , Rasgon Jason L
Published: February 2022

Background

Anopheles gambiae densovirus (AgDNV) is an insect-specific, single-stranded DNA virus that infects An. gambiae, the major mosquito species responsible for transmitting malaria parasites throughout Sub-Saharan Africa. AgDNV is a benign virus that is very specific to its mosquito host and therefore has potential to serve as a vector control tool via paratransgenesis (genetic modification of mosquito symbionts) to limit transmission of human pathogens. Prior to being engineered into a control tool, the natural transmission dynamics of AgDNV between An. gambiae mosquitoes needs to be fully understood. Additionally, improved knowledge of AgDNV infection in male mosquitoes is needed. In this study, we examine the tissue tropism of AgDNV in the male reproductive tract and investigate both venereal and vertical transmission dynamics of the virus.

Methods

An. gambiae adult males were infected with AgDNV via micro-injection and reproductive tissues collected and assayed for AgDNV using qPCR. Next, uninfected females were introduced to AgDNV-infected or control males and, after several nights of mating, both the spermatheca and female carcass were assessed for venereally transmitted AgDNV. Finally, F1s from this cross were collected and assayed to quantify vertical transmission of the virus.

Results

AgDNV infected the reproductive tract of male mosquitoes, including the testes and male accessory glands (MAGs), without affecting mating rates. AgDNV-infected males venereally transmitted virus to females, and these venereally-infected females developed disseminated infection throughout the body. However, AgDNV was not vertically transmitted to F1s resulting from this cross.

Conclusions

Infected male releases could be an effective strategy to introduce AgDNV-based paratransgenic tools into naïve populations of An. gambiae females.
Long-term antibody response to SARS-CoV-2 in children
Authors: Dunay Gabor A. , Barroso Madalena , Woidy Mathias , Danecka Marta K. , Engels Geraldine , Hermann Katharina , Neumann Friederike S. , Paul Kevin , Beime Jan , Escherich Gabriele , Fehse Kristin , Grinstein Lev , Haniel Franziska , Haupt Luka J. , Hecher Laura , Kehl Torben , Kemen Christoph , Kemper Markus J. , Kobbe Robin , Kohl Aloisa , Klokow Thomas , Nörz Dominik , Olfe Jakob , Schlenker Friderike , Schmiesing Jessica , Schrum Johanna , Sibbertsen Freya , Stock Philippe , Tiede Stephan , Vettorazzi Eik , Zazara Dimitra E. , Zapf Antonia , Lütgehetmann Marc , Oh Jun , Mir Thomas S. , Muntau Ania C. ,   the C19.CHILD Study Group, Gersting Søren W.
Published: February 2022

Almost two years into the pandemic and with vaccination of children significantly lagging behind adults, long-term pediatric humoral immune responses to SARS-CoV-2 are understudied. The C19.CHILD Hamburg (COVID-19 Child Health Investigation of Latent Disease) Study is a prospective cohort study designed to identify and follow up children and their household contacts infected in the early 2020 first wave of SARS-CoV-2. We screened 6113 children <18 years by nasopharyngeal swab-PCR in a low-incidence setting after general lockdown, from May 11 to June 30, 2020. 4657 participants underwent antibody testing. Positive tests were followed up by repeated PCR and serological testing of all household contacts over 6 months. In total, the study identified 67 seropositive children (1.44 %), the median time after infection at first presentation was 83 days post-symptom onset (PSO). Follow up of household contacts showed incomplete seroconversion in most families, with higher seroconversion rates in families with adult index cases compared to pediatric index cases (OR: 1.79, P=0.047). Most importantly, children showed sustained seroconversion up to nine months PSO, and serum antibody concentrations persistently surpassed adult levels (ratio serum IgG Spike children vs. adults 90 days PSO: 1.75, P<0.001, 180 days: 1.38, P=0.01, 270 days: 1.54, P=0.001).

In a low-incidence setting, SARS-CoV-2 infection and humoral immune response present distinct patterns in children including higher antibody levels, and lower seroconversion rates in families with pediatric index cases. Children show long-term SARS-CoV-2 antibody responses. These findings are relevant to novel variants with increased disease burden in children, as well as for the planning of age-appropriate vaccination strategies.
Omission responses in field potentials but not spikes in rat auditory cortex
Authors: Auksztulewicz Ryszard , Rajendran Vani Gurusamy , Peng Fei , Schnupp Jan Wilbert Hendrik , Harper Nicol Spencer
Published: February 2022

Non-invasive recordings of gross neural activity in humans often show responses to omitted stimuli in steady trains of identical stimuli. This has been taken as evidence for the neural coding of prediction or prediction error. However, evidence for such omission responses from invasive recordings of cellular-scale responses in animal models is scarce. Here, we sought to characterise omission responses using extracellular recordings in the auditory cortex of anaesthetised rats. We profiled omission responses across local field potentials (LFP), analogue multiunit activity (AMUA), and single/multi-unit spiking activity, using stimuli that were fixed-rate trains of acoustic noise bursts where 5% of bursts were randomly omitted. Significant omission responses were observed in LFP and AMUA signals, but not in spiking activity. These omission responses had a lower amplitude and longer latency than burst-evoked sensory responses, and omission response amplitude increased as a function of the number of preceding bursts. Contrary to theories of neural entrainment, rhythmic stimulus presentation did not increase low-frequency phase-locking of neural activity specific to the stimulus presentation rate. Together, our findings show that omission responses are observed in LFP and AMUA signals, with laminar specificity, but are not observed in spiking activity, and do not show evidence for low-frequency phase locking. This has implications for models of cortical processing that require many neurons to encode prediction error in their spike output, and may have some consistency with representation of error in dendrites electrotonically distant from the soma.
Active vibration reductions of a lift-offset compound helicopter using individual blade pitch control with multiple harmonic inputs
Authors: Kwon Young-Min , Hong Sung-Boo , Park Jae-Sang , Lee Yu-Been
Published: February 2022

Purpose

The purpose of this study is to use the individual blade pitch control (IBC), reduce actively both the rotor hub vibratory loads and airframe vibration responses for the lift-offset compound helicopter at a high-speed flight condition.

Design/methodology/approach

The Sikorsky X2 technology demonstrator (X2TD) is used as the lift-offset compound helicopter. The X2TD lift-offset rotor is modelled and its rotor hub vibratory loads at a flight speed of 250 knots are predicted using a rotorcraft comprehensive analysis code, CAMRAD II, and the airframe structural dynamics is represented with a finite element analysis code, MSC.NASTRAN. When the propulsive trim methodology is applied for rotor trim, the best input condition for IBC using multiple harmonic inputs is searched to reduce the rotor vibration, while the rotor aerodynamic performance (the rotor effective lift-to-drag ratio) is improved or maintained at least. Finally, the reduction in airframe vibration responses is investigated when the best input condition for IBC with multiple harmonics is applied to the lift-offset rotor.

Findings

When the IBC with the single harmonic input using the 2/rev actuation frequency, amplitude of 2° and control phase angle of 120° (2P/2°/120°) is considered for X2TD rotor, the rotor vibration is reduced by about 26.37% only and the rotor effective lift-to-drag ratio increases slightly by 0.98%. When X2TD rotor uses the IBC with multiple harmonic inputs (2P/2°/45° + 5P/1°/90°), the rotor hub vibratory loads and airframe vibration responses are reduced by 44.69% and from 0.48 to 79.10%, respectively, while rotor effective lift-to-drag ratio is improved by 0.77%, as compared to the baseline without IBC.

Originality/value

This study is the first study to use the 2/rev actuation for IBC to the four-bladed lift-offset coaxial rotor and to investigate to obtain simultaneously the rotor vibration reduction, rotor performance improvement and airframe vibration reduction, using IBC with multiple harmonic inputs.
Impact of mobilization costs on schedule performance of highway projects
Authors: Maharjan Shristy , Shrestha Pramen P. , Srirangam Deekshitha
Published: February 2022

Purpose

The purpose of this study is to determine whether there is a correlation between mobilization costs and project schedule performance of highway projects. In addition to this, the study will also determine if the mobilization costs are helping small or large highway projects in terms of improving the schedule performance.

Design/methodology/approach

The data of 206 highway projects were collected from the Department of Transportation of two states with the help of questionnaire survey. The cost, schedule and mobilization costs data were collected. The performance metrics related to construction schedule growth and construction intensity were developed in order to test the research hypotheses: mobilization costs will increase the schedule performance of highway projects. The data were also divided into two groups based on project cost and analyzed to check whether the mobilization costs impact the schedule performance of these highway projects. Spearman's correlation test was conducted to determine the correlation between dependent and independent variables. In addition, a Mann–Whitney test was conducted to determine the difference in medians of construction schedule growth and the construction intensity of these two groups of projects.

Findings

One major study finding was that there was no strong linear correlation between the mobilization cost percentage and the construction schedule growth and construction intensity of highway projects. However, the study found the projects that have 9% or more mobilization costs had significantly better schedule growth compared to the projects that have less than 9% mobilization costs. When data were analyzed based on the project size, it was found that this pattern was seen only in large projects costing equal to or more than $5 million.

Practical implications

This study's findings have very crucial practical implications to state DOTs contract engineers. This study shows that the highway contract engineers need to provide the right amount of mobilization costs to complete their projects on and before schedule. If the correct amount of mobilization costs is not provided to the contractors, the impact of these mobilization costs on reducing the schedule growth will be negligible. The findings of this study will assist public agency decision makers to complete their projects on or before time by including the mobilization costs provision in the contract. The state DOTs can improve their schedule performance by providing enough financial help to the contractors so that they can improve their cash flows and complete projects successfully within the given timeframe.

Originality/value

This paper contributes to the existing body of knowledge by validating the impact of mobilization costs on the schedule performance of highway projects. There has been no empirical study conducted prior to this to identify the role of mobilization costs on reducing the schedule growth of highway projects.
Ellerine holdings and African bank: a toxic acquisition recipe?
Authors: Kodongo Odongo , Beswick Claire , van den Berg Helen
Published: February 2022

Learning outcomes

After working through and discussing this case, learners should be able to:1. evaluate the financial condition of Ellerine Holdings Limited (EHL) at the time of the merger proposal and use it to make inferences about the company’s ability, at that time, to function effectively as a going concern;2. identify the conditions within EHL and in the operating environment that may have made it necessary for EHL to seek to change its business strategy;3. determine whether the acquisition price offered to EHL by African Bank Investments Limited (ABIL) was fair; and4. compute the value accretion/loss expected to be realised by the existing shareholders of ABIL and EHL under the merger proposal.

Case overview/synopsis

This case situates the directors of Ellerine Holdings, a furniture retail company that merged with African Bank Limited in 2007, reflecting on the events that led up to both entities being placed into business rescue in 2014 and asking whether the merger was the cause of the demise. If they had chosen an alternative partner, would the results have been different?

Complexity academic level

Masters Level students – MBA or Masters in Finance.

Supplementary materials

For instructors.The following material has been provided with the teaching note for instructors:- Teaching Note.- Johannesburg Stock Exchange News System (SENS) extract of related original filing.For students.The following supplementary material has been provided to accompany the case:- Financial information on the two companies (Excel spreadsheet).- Johannesburg SENS extract of related original filing.

Subject code

CSS 1: Accounting and Finance.
Alibaba: the battle against counterfeits
Authors: Jyani Nancy , Bansal Harbhajan
Published: February 2022

Learning outcomes

The case will help to understand the concept of online marketplaces and the working of their business model through third party selling. The case highlights how third party selling opens door to online counterfeiting. The case well presents the need of integrity and ethics in business. It showcases how Alibaba took responsibility, designed various initiatives to curb the problem and emerged as a global face for anti-counterfeiting actions.

Case overview/synopsis

Manufacturing and selling of counterfeits have become easier than ever with the wide and easy reach of technology. Internet has smoothened the sale of such fake replicas around the globe. Alibaba Group faced serious problem of counterfeit selling across its various websites. The various challenges were degrading global image, rising number of fake products and numerous lawsuits filed against the company. The case study will help readers to understand the critical aspects of counterfeiting and decisions involved to run such models where the platform is not a direct seller but just an online marketplace. It emphasises how technology and brand collaboration can be used as a means to identify and remove fake product listings from such platforms, thereby preserving the integrity of business. The case also stresses the need to preserve intellectual property rights and exclusivity of original brands.

Complexity academic level

Senior Undergraduate, MBA and Executive MBA.

Supplementary materials

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Subject code

CSS 8: Marketing.
The Spinach King’s social enterprise scaling strategy during and post Covid-19 pandemic
Authors: Mamabolo Anastacia
Published: February 2022

Learning outcomes

Analyse a social business model; explain the scaling motives in a social enterprise; identify and defend scaling strategies in a social enterprise; and use the social enterprise scaling barrier model to evaluate factors that contribute to scaling failure and suggest ways to address the identified barriers.

Case overview/synopsis

Lufefe Nomjana, a Cape Town-based social entrepreneur, decided in 2011 to launch a social enterprise that promotes an affordable but healthy lifestyle by baking and selling spinach bread at a low cost. Nomjana combined a for-profit business venture with the social aspect of providing healthy products at a cost people can afford. When the lockdown was implemented in South Africa in March 2020, he still grew his business despite the strict restrictions. Inspired by the growth of the enterprise, in August 2020, and at the height of the national lockdown necessitated by the Covid-19 pandemic, Nomjana decided to open a company-owned outlet in Johannesburg miles away from the Cape. However, the launch of this company-owned outlet was not successful. The failure of the Johannesburg outlet left him with a dilemma, as he had planned to scale up his enterprise into other cities in South Africa. Launching his business in Cape Town had not been a challenge, but he struggled to launch outlets of his social enterprise outside of the Western Cape Province.

Complexity academic level

Social Entrepreneurship, Commercial Entrepreneurship and Business Management at the Postgraduate Diploma and Masters level.

Supplementary materials

Teaching notes are available for educators only.

Subject code

CCS 3: Entrepreneurship.
Factors that influence service innovation: a systematic approach and a categorization proposal
Authors: Peixoto Marcus Rodrigues , Paula Fabio de Oliveira , da Silva Jorge Ferreira
Published: February 2022

Purpose

Service innovation (SI) is crucial for social and economic development. However, most of the studies about innovation relate to product/manufacturing. Aimed at enhancing the academic debate about SI, this paper intends to (1) assess the factors applied in empirical studies about SI from 2006 to 2020, (2) evaluate if researchers differentiate innovation in services from innovation in manufacturing, (3) evaluate if researchers differentiate innovation among distinct service segments within the heterogeneous service industry and (4) propose a categorization model for the factors that influence SI.

Design/methodology/approach

Our study employs a five-step approach for a systematic literature review of 99 relevant empirical papers from 2006 to 2020.

Findings

Our findings demonstrate a persistent lack of conceptual consolidation in the area, adding value to the ongoing dispute between opposite views on current SI's maturity level. Our results also evidence the non-observance of differentiation of innovation factors between service and manufacturing empirical papers. In addition, our paper shows an even higher lack of differentiation in the use of innovation factors among different service segments.

Originality/value

This paper provides the first more systematic verification of the lack of service differentiation within the empirical innovation study field. In addition, despite the abundance of factors that influence SI, the proposed categorization model offers the possibility to promote an area's conceptual consolidation. Our findings and categorization also support the debate about pathways for the field's development and help researchers in their future study designs and analyses.
Dynamic capabilities configurations: the firm lifecycle and the interplay of DC dimensions
Authors: Cordero Páez Laura Cristina , Pinho José Carlos , Prange Christiane
Published: February 2022

Purpose

Dynamic capabilities (DCs) upgrade operational capabilities. However, DC dimensions of sensing, seizing and reconfiguring may combine in different configurations that result in alternative outcomes, depending on the firm's lifecycle stage. The purpose of this research is to explore configurations of DC dimensions during different stages of firms' lifecycles that result in operational marketing and technological capabilities.

Design/methodology/approach

Given the limited understanding of how DC dimensions and operational capabilities interact across a firm's lifecycle, the authors employed a multi-method approach to understand whether different configurations of DC dimensions may lead to operational marketing and technological capabilities and how the firm's lifecycle may condition these configurations. The authors first apply PLS path modelling to assess the validity and reliability of the measures. Then, the authors use fuzzy-set qualitative comparative analysis (fsQCA) to analyse micro, small and medium-sized enterprises (SMEs) in different growth stages operating in the creative industry within highly competitive and fast-changing environments.

Findings

Results show that several configurations of DC dimensions and competitive intensity influence marketing and technological capabilities. Although several configurations include sensing, seizing and reconfiguring, the findings also point to configurations where not all DC dimensions are present.

Practical implications

Improving operational capabilities does not necessarily imply a simultaneous presence of all three DC dimensions. Especially in the growth stage, managers that face resources shortage may only focus on sensing and seizing dimensions when developing marketing capabilities.

Originality/value

This research focuses on configurations of DC dimensions (instead of configurations of different types of DCs) that generate diverse marketing and technological capabilities development paths. The authors provide several equifinal configurations of DC dimensions that lead to operational marketing and technological capabilities. This study contributes to disentangling DCs and their dimensions across different lifecycle stages.
Some thoughts on resetting the roles and functions of Sharīʿah committees of Islamic banks in Malaysia
Authors: Isa Mansor , Lee Siew-Peng , Bacha Obiyathulla Ismath , Ahmad Rubi
Published: February 2022

Purpose

The purpose of this study is to understand and evaluate the roles and functions of the Sharīʿah committee (SC) of Islamic banks (IBs) in Malaysia and to recommend a resetting of the scope of responsibilities to enable the SC to effectively respond to current market needs.

Design/methodology/approach

A Likert-type survey questionnaire was developed and distributed to all available SC members through e-mails and online surveys as well as self-administered questionnaires. At the end of the survey, 87 useable questionnaires were collected from 161 SC members, representing a 54% response rate.

Findings

This study finds that most SC members have the necessary Sharīʿah qualification, and they are mostly academics with doctoral degrees. However, there is a noticeable lack of diversity in the composition of experts in the committees. Respondents indicate that their main functions are to ensure Sharīʿah compliance of bank operations and product offerings. This is of course consistent with their stated functions as outlined in the Bank Negara Malaysia's Sharīʿah Governance Policy Document (BNM, 2019). The study finds that SCs are not involved in product development, nor responsible for financial performance. Respondents indicate three ways to enhance the role of SCs: improving banking knowledge of the members, more engagement with the board of directors (BoDs) and broadening the functions of SCs.

Practical implications

This study highlights two policy implications. First, there is a strategic need for IBs to consider having a diversity of expertise in the SCs while maintaining the Sharīʿah experts as core members. Second, this study recommends a reset of the scope of duties of the SC to include three new areas: risk management, product development and financial performance.

Originality/value

This study evaluates the current functions of the SC of IBs in Malaysia and provides suggestions for improvement in the composition of the committee and in the scope of duties of SCs based on contemporary needs.
Ethical leadership in multinational companies’ control practices: culture as a moderating factor
Authors: Zhang Huayao , Wu Junjie , Wen Jing , Douglas David
Published: February 2022

Purpose

Determining the role of ethical leadership in the multinational companies’ (MNCs) control practices, the purpose of this paper is to extend Eisenbeiss’ (2012) four central ethical leadership orientations into multinational companies’ control contexts – the culturally diversified environment.

Design/methodology/approach

Adopting a multiple-case research design, the authors gather qualitative data from four MNC subsidiaries located in China, that connects three potentially diverse cultural contexts: German, Japanese and Chinese.

Findings

The findings of this paper confirm that ethical leadership compliance (or violation) positively (or negatively) contributes to the internalization of organizational practice transfer, moderated by cultural distance between foreign managers and subsidiaries’ employees. The results reveal that informal control and trust act as lubricants in the internalization process.

Originality/value

This paper evidences the connections between ethical leadership, organizational practice transfer and subsequent performance, along with inclusive cultural moderating factors.