bluuebunny/crossref_metadata_2025 huggingface dataset:
Spontaneous isomerization of long-lived proteins provides a molecular mechanism for the lysosomal failure observed in Alzheimer’s disease
Authors: Lambeth Tyler R. , Riggs Dylan L. , Talbert Lance E. , Tang Jin , Coburn Emily , Kang Amrik S. , Noll Jessica , Augello Catherine , Ford Byron D. , Julian Ryan R.
Published: April 2019

Proteinaceous aggregation is a well-known observable in Alzheimer’s disease (AD), but failure and storage of lysosomal bodies within neurons is equally ubiquitous and actually precedes bulk accumulation of extracellular amyloid plaque. In fact, AD shares many similarities with certain lysosomal storage disorders though establishing a biochemical connection has proven difficult. Herein, we demonstrate that isomerization and epimerization, which are spontaneous chemical modifications that occur in long-lived proteins, prevent digestion by the proteases in the lysosome (namely the cathepsins). For example, isomerization of aspartic acid into L-isoAsp prevents digestion of the N-terminal portion of Aβ by cathepsin L, one of the most aggressive lysosomal proteases. Similar results were obtained after examination of various target peptides with a full series of cathepsins, including endo-, amino-, and carboxy-peptidases. In all cases peptide fragments too long for transporter recognition or release from the lysosome persisted after treatment, providing a mechanism for eventual lysosomal storage and bridging the gap between AD and lysosomal storage disorders. Additional experiments with microglial cells confirmed that isomerization disrupts proteolysis in active lysosomes. These results are easily rationalized in terms of protease active sites, which are engineered to precisely orient the peptide backbone and cannot accommodate the backbone shift caused by isoaspartic acid or side chain dislocation resulting from epimerization. Although Aβ is known to be isomerized and epimerized in plaques present in AD brains, we further establish that the rates of modification for aspartic acid in positions 1 and 7 are fast and could accrue prior to plaque formation. Spontaneous chemistry can therefore provide modified substrates capable of inducing gradual lysosomal failure, which may play an important role in the cascade of events leading to the disrupted proteostasis, amyloid formation, and tauopathies associated with AD.
Dynamic cerebral autoregulation of endurance-trained men following 6 weeks of high-intensity interval training to exhaustion
Authors: Drapeau Audrey , Labrecque Lawrence , Imhoff Sarah , Paquette Myriam , Le Blanc Olivier , Malenfant Simon , Brassard Patrice
Published: April 2019

Elevated cardiorespiratory fitness (CRF) is associated with reduced dynamic cerebral autoregulation (dCA), but the impact of exercise trainingper seon dCA remains equivocal. In addition, resting cerebral blood flow (CBF) and dCA after high-intensity interval training (HIIT) in individuals with already high CRF is unknown. We examined to what extent 6 weeks of HIIT affect resting CBF and dCA in cardiorespiratory fit men and explored if potential changes are intensity-dependent. Endurance-trained men were assigned to group HIIT85(85% of maximal aerobic power, 1 to 7 min effort bouts, n = 8) and HIIT115(115% of maximal aerobic power, 30 s to 1 min effort bouts, n = 9). Training sessions were completed until exhaustion 3 times/week over 6 weeks. Mean arterial pressure (MAP) and middle cerebral artery mean blood velocity (MCAvmean) were measured continuously at rest and during repeated squat-stands (0.05 and 0.10 Hz). Transfer function analysis (TFA) was used to characterize dCA on driven blood pressure oscillations during repeated squat-stands. Neither training nor intensity had an effect on resting MAP and MCAvmean(bothP> 0.05). TFA phase during 0.10 Hz squat-stands decreased after HIIT irrespective of intensity (HIIT85: 0.77 ± 0.22 vs. 0.67 ± 0.18 radians; HIIT115: pre: 0.62 ± 0.19 vs. post: 0.59 ± 0.13 radians, time effectP= 0.048). These results suggest that HIIT over 6 weeks have no apparent benefits on resting CBF, but a subtle attenuation in dCA is seen posttraining irrespective of intensity training in endurance-trained men.

NEW & NOTEWORTHY

The novel findings of this study are that 6 weeks of submaximal and supramaximal high-intensity interval exercise to exhaustion reduce dynamic cerebral autoregulation irrespective of training intensity in endurance-trained men. However, these HIIT protocols do not influence resting cerebral blood flow in these individuals. The results indicate the cerebrovasculature of endurance-trained men has an attenuated ability to react to large and rapid changes in blood pressure following HIIT.
Complex responses to inflammatory oxidants by the probiotic bacteriumLactobacillus reuteri
Authors: Thakur Poulami Basu , Long Abagail R. , Nelson Benjamin J. , Kumar Ranjit , Rosenberg Alexander F. , Gray Michael J.
Published: April 2019

Inflammatory diseases of the gut are associated with increased intestinal oxygen concentrations and high levels of inflammatory oxidants, including hydrogen peroxide (H2O2) and hypochlorous acid (HOCl), which are antimicrobial compounds produced by the innate immune system. This contributes to dysbiotic changes in the gut microbiome, including increased populations of pro-inflammatory enterobacteria (Escherichia coliand related species) and decreased levels of health-associated anaerobic Firmicutes and Bacteroidetes. The pathways for H2O2and HOCl resistance inE. colihave been well-studied, but little is known about how commensal and probiotic bacteria respond to inflammatory oxidants. In this work, we have characterized the transcriptomic response of the anti-inflammatory, gut-colonizing Gram-positive probioticLactobacillus reuterito both H2O2and HOCl.L. reuterimounts distinct responses to each of these stressors, and both gene expression and survival were strongly affected by the presence or absence of oxygen. Oxidative stress response inL. reuterirequired several factors not found in enterobacteria, including the small heat shock protein Lo18, polyphosphate kinase 2, and RsiR, anL. reuteri-specific regulator of anti-inflammatory mechanisms. These results raise the intriguing possibility of developing treatments for inflammatory gut diseases that could sensitize pro-inflammatory enterobacteria to killing by the immune system while sparing anti-inflammatory, health-associated species.

IMPORTANCE

It is becoming increasingly clear that effective treatment of inflammatory gut diseases will require modulation of the gut microbiota. Preventing pro-inflammatory bacteria from blooming while also preserving anti-inflammatory and commensal species is a considerable challenge, but our results suggest that it may be possible to take advantage of differences in the way different species of gut bacteria resist inflammatory oxidants to accomplish this goal.
The bacterial leader peptide peTrpL has a conserved function in antibiotic-dependent posttranscriptional regulation of ribosomal genes
Authors: Melior Hendrik , Maaß Sandra , Stötzel Maximilian , Li Siqi , Förstner Konrad U. , Schütz Rubina , Azarderakhsh Saina , Shevkoplias Aleksei , Barth-Weber Susanne , Varadarajan Adithi R. , Baumgardt Kathrin , Chervontseva Zoe , Ziebuhr John , Ahrens Christian H. , Becher Dörte , Evguenieva-Hackenberg Elena
Published: April 2019

The ribosome-dependent attenuator located upstream of bacterial tryptophan biosynthesis genes harbors a small ORF trpL containing tryptophan codons. When tryptophan is available, efficient trpL translation causes transcription termination and release of the attenuator RNA rnTrpL. In Sinorhizobium meliloti, rnTrpL is a trans-acting sRNA. Here, we identified an evolutionary conserved function for the trpL-encoded 14-aa leader peptide peTrpL. Upon exposure to tetracycline, the cellular peTrpL levels were increased and rnTrpL was generated independently of tryptophan availability. Both peTrpL and rnTrpL were found to be involved in tetracycline-dependent destabilization of rplUrpmA mRNA encoding ribosomal proteins L21 and L27. We provide evidence for redirection of the sRNA rnTrpL from its antibiotic-independent target trpDC to rplUrpmA by formation of an antibiotic-dependent ribonucleoprotein complex (ARNP). ARNPs comprising peTrpL, rnTrpL, rplUrpmA and antisense RNA were also observed for other translation-inhibiting antibiotics, suggesting that bacteria evolved mechanisms to utilize antibiotics for mRNA destabilization.
Iba1+Microglia Exhibit Morphological Differences between Inferior Colliculus Sub-Regions and Their Abutments ontoGAD67+Somata Reveal Two Novel Sub-types of GABAergic Neuron
Authors: Webb Samuel David , Orton Llwyd David
Published: April 2019

Microglia have classically been viewed as the endogenous phagocytes of the brain, however, emerging evidence suggests roles for microglia in the healthy, mature nervous system. We know little of the contribution microglia make to ongoing processing in sensory systems. To exploreIba1+microglial diversity, we employed the inferior colliculi (IC) as model nuclei, as they are characterized by sub-regions specialized for differing aspects of auditory processing. We conducted fluorescent multi-channel immunohistochemistry and confocal microscopy in guinea pigs of both sexes and discovered that the density and morphology ofIba1+labelling varied between parenchymal sub-regions of IC, whileGFAP+labelling of astrocytes was confined to theglia limitans externaandperi-vascular regions. The density ofIba1+microglia somata was similar across sub-regions, however a greater amount of labelling was found in dorsal cortex than ventral central nucleus or lateral cortex. To further understand these differences between sub-regions in IC, Sholl and skeleton analyses of individual microglia revealed a greater number of branching ramifications in dorsal cortex. We also quantified abutments ofIba1+microglial processes ontoGAD67+(putative GABAergic) somata. Cluster analyses revealed two novel sub-types ofGAD67+neuron, which can be distinguished solely based on the quantity of axo-somaticIba1+abutments they receive. These data demonstrateIba1+microglia exhibit different morphologies and interactions withGAD67+neurons in distinct sub-regions of the mature, healthy IC. Taken together, these findings suggest significant heterogeneity amongst microglia in the auditory system, possibly related to the ongoing functional demands of their niche.
The BLIMP1 – EZH2 nexus in a non-Hodgkin lymphoma
Authors: Anderson Kimberley Jade , Ósvaldsdóttir Árný Björg , Atzinger Birgit , Traustadóttir Gunnhildur Ásta , Nolling Jensen Kirstine , Lárusdóttir Aðalheiður Elín , Bergþorsson Jón Þór , Harðardóttir Ingibjörg , Magnúsdóttir Erna
Published: April 2019

Waldenström’s macroglobulinemia (WM) is a non-Hodgkin lymphoma, resulting in antibody-secreting lymphoplasmacytic cells in the bone marrow and pathologies resulting from high levels of monoclonal immunoglobulin M (IgM) in the blood. Despite the key role for BLIMP1 in plasma cell maturation and antibody secretion, its potential role in WM cell biology has not yet been explored. Here we provide evidence of a crucial role for BLIMP1 in the survival of WM cells and further demonstrate that BLIMP1 is necessary for the expression of the histone methyltransferase EZH2 in both WM and multiple myeloma. The effect of BLIMP1 on EZH2 levels is post translational, at least partially through the regulation of proteasomal targeting of EZH2. Chromatin immunoprecipitation analysis and transcriptome profiling suggest that the two factors co-operate in regulating genes involved in cancer cell immune evasion. Co-cultures of natural killer cells and WM cells further reveal that both factors participate directly in immune evasion, promoting escape from natural killer cell mediated cytotoxicity. Together, the interplay of BLIMP1 and EZH2 plays a vital role in promoting the survival of WM cells.
DeeplyEssential: A Deep Neural Network for Predicting Essential Genes in Microbes
Authors: Hasan Md Abid , Lonardi Stefano
Published: April 2019

Essential genes are genes that critical for the survival of an organism. The prediction of essential genes in bacteria can provide targets for the design of novel antibiotic compounds or antimicrobial strategies. Here we propose a deep neural network (DNN) for predicting essential genes in microbes. Our DNN-based architecture called DeeplyEssentialmakes minimal assumptions about the input data (i.e., it only uses gene primary sequence and the corresponding protein sequence) to carry out the prediction, thus maximizing its practical application compared to existing predictors that require structural or topological features which might not be readily available. Our extensive experimental results show that DeeplyEssentialoutperforms existing classifiers that either employ down-sampling to balance the training set or use clustering to exclude multiple copies of orthologous genes. We also expose and study a hidden performance bias that affected previous classifiers.

The code of DeeplyEssentialis freely available athttps://github.com/ucrbioinfo/DeeplyEssential
Environment Shapes the Accessible Daptomycin Resistance Mechanisms inEnterococcus faecium
Authors: Prater Amy G. , Mehtaa Heer , Kosgei Abigael J. , Miller William R. , Tran Truc T. , Arias Cesar A. , Shamoo Yousif
Published: April 2019

Daptomycin binds to bacterial cell membranes and disrupts essential cell envelope processes leading to cell death. Bacteria respond to daptomycin by altering their cell envelopes to either decrease antibiotic binding to the membrane or by diverting binding away from vulnerable septal targets to remodeled anionic phospholipid membrane patches. InEnterococcus faecalis, daptomycin resistance is typically coordinated by the three-component cell-envelope-stress-response system, LiaFSR. Here, studying a clinical strain of multidrug-resistantEnterococcus faeciumcontaining alleles associated with activation of the LiaFSR signaling pathway, we found that specific environments selected for different evolutionary trajectories leading to high-level daptomycin resistance. Planktonic environments favored pathways that increased cell surface charge viayvcRSupregulation ofdltABCDandmprF, causing a reduction in daptomycin binding. Alternatively, environments favoring complex structured communities, including biofilms, evolved both diversion and repulsion strategies viadivIVAandoatAmutations, respectively. Both environments subsequently converged on cardiolipin synthase (cls) mutations, suggesting the importance of membrane modification across strategies. Our findings indicate thatE. faeciumcan evolve diverse evolutionary trajectories to daptomycin resistance that are shaped by the environment to produce a combination of resistance strategies. The accessibility of multiple and different biochemical pathways simultaneously suggests that the outcome of daptomycin exposure results in a polymorphic population of resistant phenotypes makingE. faeciuma recalcitrant pathogen.
EPAC2 is required for corticotropin-releasing hormone-mediated spine loss
Authors: Xie Zhong , Penzes Peter , Srivastava Deepak P.
Published: April 2019

Corticotropin-releasing hormone (CRH) is produced in response to stress. This hormone plays a key role in mediating neuroendocrine, behavioral, and autonomic responses to stress. The CRH receptor 1 (CRHR1) is expressed in multiple brain regions including the cortex and hippocampus. Previous studies have shown that activation of CRHR1 by CRH results in the rapid loss of dendritic spines. Exchange protein directly activated by cAMP (EPAC2, also known as RapGEF4), a guanine nucleotide exchange factor (GEF) for the small GTPase Rap, has been linked with CRHR1 signaling. EPAC2 plays a critical role in regulating dendritic spine morphology and number in response to several extracellular signals. But whether EPAC2 links CRHR1 with dendritic spine remodeling is unknown. Here we show that CRHR1 is highly enriched in the dendritic spines of primary cortical neurons. Furthermore, we find that EPAC2 and CRHR1 co-localize in cortical neurons. Critically, short hairpin RNA-mediated knockdown of Epac2 abolished CRH-mediated spine loss in primary cortical neurons. Taken together, our data indicate that EPAC2 is required for the rapid loss of dendritic spines induced by CRH. These findings identify a novel pathway by which acute exposure to CRH may regulate synaptic structure and ultimately responses to acute stress.
PRDM1 controls the sequential activation of neural, neural crest and sensory progenitor determinants by regulating histone modification
Authors: Prajapati Ravindra S. , Hintze Mark , Streit Andrea
Published: April 2019

During early embryogenesis, the ectoderm is rapidly subdivided into neural, neural crest and sensory progenitors. How the onset of lineage-specific determinants and the loss of pluripotency markers are temporally and spatially coordinated in vivo remains an open question. Here we identify a critical role for the transcription factor PRDM1 in the orderly transition from epiblast to defined neural lineages. Like pluripotency factors,PRDM1is expressed in all epiblast cells prior to gastrulation, but lost as they begin to differentiate. We show that, unlike pluripotency factors, PRDM1 is initially required for the activation of neural, neural crest and sensory progenitor specifiers and for the downregulation of pluripotency-associated genes. In vivo chromatin immunoprecipitation reveals stage-specific binding of PRDM1 to regulatory regions of neural and sensory progenitor genes, PRDM1-dependent recruitment of the histone demethylase Kdm4a to these regions and associated removal of repressive histone marks. Once lineage determinants become expressed, they repressPRDM1, and our data suggest thatPRDM1downregulation is required for cells to maintain their identity. Thus, PRDM1 mediates chromatin modifications that directly control neural and sensory progenitor genes, and its activities switch from an activator at early stages to a repressor once neural fates have been established.
Brain age prediction reveals aberrant brain white matter in schizophrenia and bipolar disorder: A multi-sample diffusion tensor imaging study
Authors: Tønnesen Siren , Kaufmann Tobias , de Lange Ann-Marie , Richard Genevieve , Doan Nhat Trung , Alnæs Dag , van der Meer Dennis , Rokicki Jaroslav , Moberget Torgeir , Maximov Ivan I. , Agartz Ingrid , Aminoff Sofie R. , Beck Dani , Barch Deanna , Beresniewicz Justyna , Cervenka Simon , Bergman Helena Fatouros , Craven Alexander R. , Flyckt Lena , Gurholt Tiril P. , Haukvik Unn K. , Hugdahl Kenneth , Johnsen Erik , Jönsson Erik G. ,   KaSPi, Kolskår Knut K. , Kompus Kristiina , Kroken Rune Andreas , Lagerberg Trine V. , Løberg Else-Marie , Nordvik Jan Egil , Sanders Anne-Marthe , Ulrichsen Kristine , Andreassen Ole A. , Westlye Lars T.
Published: April 2019

Background

Schizophrenia (SZ) and bipolar disorders (BD) share substantial neurodevelopmental components affecting brain maturation and architecture. This necessitates a dynamic lifespan perspective in which brain aberrations are inferred from deviations from expected lifespan trajectories. We applied machine learning to diffusion tensor imaging (DTI) indices of white matter structure and organization to estimate and compare brain age between patients with SZ, BD, and healthy controls across 10 cohorts.

Methods

We trained six cross-validated models using different combinations of DTI data from 927 healthy controls (HC, 18-94 years), and applied the models to the test sets including 648 SZ (18-66 years) patients, 185 BD patients (18-64 years), and 990 HC (17-68 years), estimating brain age for each participant. Group differences were assessed using linear models, accounting for age, sex, and scanner. A meta-analytic framework was applied to assess the heterogeneity and generalizability of the results.

Results

10-fold cross-validation revealed high accuracy for all models. Compared to controls, the model including all feature sets significantly over-estimated the age of patients with SZ (d=-.29) and BD (d=.18), with similar effects for the other models. The meta-analysis converged on the same findings. Fractional anisotropy (FA) based models showed larger group differences than the models based on other DTI-derived metrics.

Conclusions

Brain age prediction based on DTI provides informative and robust proxies for brain white matter integrity. Our results further suggest that white matter aberrations in SZ and BD primarily consist of anatomically distributed deviations from expected lifespan trajectories that generalize across cohorts and scanners.
1-Chloro-4-[2-(4-chlorophenyl)ethyl]benzene and its bromo analogue: crystal structure, Hirshfeld surface analysis and computational chemistry
Authors: Jotani Mukesh M. , Lee See Mun , Lo Kong Mun , Tiekink Edward R. T.
Published: April 2019

The crystal and molecular structures of C14H12Cl2, (I), and C14H12Br2, (II), are described. The asymmetric unit of (I) comprises two independent molecules, A and B, each disposed about a centre of inversion. Each molecule approximates mirror symmetry [the Cb—Cb—Ce—Ce torsion angles = −83.46 (19) and 95.17 (17)° for A, and −83.7 (2) and 94.75 (19)° for B; b = benzene and e = ethylene]. By contrast, the molecule in (II) is twisted, as seen in the dihedral angle of 59.29 (11)° between the benzene rings cf. 0° in (I). The molecular packing of (I) features benzene-C—H...π(benzene) and Cl...Cl contacts that lead to an open three-dimensional (3D) architecture that enables twofold 3D–3D interpenetration. The presence of benzene-C—H...π(benzene) and Br...Br contacts in the crystal of (II) consolidate the 3D architecture. The analysis of the calculated Hirshfeld surfaces confirm the influence of the benzene-C—H...π(benzene) and X...X contacts on the molecular packing and show that, to a first approximation, H...H, C...H/H...C and C...X/X...C contacts dominate the packing, each contributing about 30% to the overall surface in each of (I) and (II). The analysis also clearly differentiates between the A and B molecules of (I).
Organizations need ethical leaders: how to attract and nurture cultural creatives into positions of leadership and influence
Authors: Gardner Paula Kay , Holloway Mark
Published: April 2019

Purpose

This paper aims to look at the growing need for ethical leaders, suggesting that a strata of society called “cultural creatives” may answer that need. It investigates how the cultural creatives can be attracted and nurtured in positions of leadership and puts forward tangible action points and suggestions to help organizations take practical actions.

Design/methodology/approach

The paper is an interpretative phenomenological analysis of four cultural creatives who are in positions of leadership.

Findings

The finding with the maximum impact for organizations perhaps is that they all left positions where they felt unsupported and undeveloped, rather than push their employer for that support. Participants were predictably people-oriented, although this meant different things for each person. Their styles of leadership varied, but all shared a desire to become role models and leave a legacy. Only one worked within the third sector, and all were quite pragmatic and motivated by money, something that seems to be different from the original research on this group.

Practical implications

The paper highlights five key indicators organizations must consider to attract and nurture cultural creatives: flexibility in leadership style, levels of autonomy, acting as mentors, appropriate financial rewards, and opportunities for authentic, self-determined work.

Social implications

The cultural creatives are reportedly the third largest social strata in Western society, after the modernists and traditionalists. They are growing as a group, and this study looks at how they operate and feel about their workplace. It provides insights into what it is like to be a cultural creative.

Originality/value

This is the only known research on cultural creatives since the original research in the early 2000s.
Southern European welfare states and homelessness: Portugal and Greece
Authors: Kourachanis Nikos
Published: April 2019

Purpose

The purpose of this paper is to compare homelessness policies in Portugal and Greece.

Design/methodology/approach

After a brief overview of the relationship between welfare regimes and homelessness, the characteristics of homelessness policies within the South-European regime are studied. Subsequently, by employing empirical data, a comparison between the homelessness policies of these two countries is attempted through three axes of analysis: the historical emergence of homelessness policies; the impact of the memoranda, as a series of fiscal measures associated with welfare retrenchment, on the deterioration of homelessness; and the characteristics of the social policies being developed.

Findings

It is noted that the two countries consolidate a residual social intervention model that fails to address homelessness adequately.

Originality/value

This is the first attempt to compare homelessness policies between Portugal and Greece.
Pricing power in insurance markets: evidence from South Africa
Authors: Alhassan Abdul Latif , Biekpe Nicholas
Published: April 2019

Purpose

In less competitive markets, firms with market power are likely to exercise pricing power by setting output prices above their marginal cost, inducing welfare losses from resource misallocation, managerial inefficiency and market instability. In order to address such market imperfections, it is important for regulatory authorities to identify the sources of pricing power and devise policies to address their adverse effects. In this context, the purpose of this paper is to undertake an empirical analysis to identify the determinants of pricing power in the South African non-life insurance market.

Design/methodology/approach

The authors estimate the Lerner competitive index as the proxy for pricing power using annual data on 79 firms from 2007 to 2012. In the second stage, the paper employs panel regression techniques in the ordinary least squares, random effects and generalised method of moment’s estimations to examine the effect of insurer level characteristics on pricing power.

Findings

The authors find the market to be characterised by firms with high pricing power. Domestic-owned insurers are found to exercise high pricing power compared with foreign-owned insurers. The authors also identify size, cost efficiency, product line diversification, market concentration, leverage and reinsurance contracts as the significant predictors of pricing power in the market. Finally, through a quantile regression analysis, the authors find the effect of cost efficiency, business line diversification and reinsurance to be heterogeneous across different quantiles of pricing power.

Practical implications

The findings provide regulatory authorities with useful indicators in addressing anti-competitive behaviour in high pricing power to enhance the stability of the insurance market and improve consumer welfare and economic development.

Originality/value

To the best of the authors’ knowledge, this is first paper to examine the determinants of pricing power and competitive behaviour in an insurance market.
Corporate debt maturity and economic development
Authors: Álvarez-Botas Celia , González-Méndez Víctor M.
Published: April 2019

Purpose

The purpose of this paper is to analyse the effect of economic development on the influence of country-level determinants on corporate debt maturity, bearing in mind firm size and the period of financial crisis.

Design/methodology/approach

The authors employ panel data estimation with fixed effects to examine the role of economic development in influencing the relationship between country-level determinants on corporate debt maturity. The paper uses a sample of 30,727 listed firms, belonging to 39 countries, over the period 2005–2012.

Findings

Corporate debt maturity increases with the efficiency of the legal system and bank concentration and decreases with the weight of banks in the economy. However, the importance of these country determinants is greater in developing than in developed countries. The authors also show that firm size in developed and developing countries influences country determinants of corporate debt maturity. Finally, the results reveal that the financial crisis has affected the debt maturity of firms differently in developed and developing countries, with the effect of bank concentration lengthening debt maturity, this effect being more pronounced in developing countries.

Practical implications

The findings provide useful insights to guide policy decisions providing access to long-term financing, as corporate debt maturity depends on economic development, institutional environment, banking structure and firm size.

Originality/value

This study incorporates economic development in explaining the relationship between country-level determinants and corporate debt maturity.
Tax avoidance in management-owned firms: evidence from Brazil
Authors: Cabello Otávio Gomes , Gaio Luiz Eduardo , Watrin Christoph
Published: April 2019

Purpose

The purpose of this paper is to test if companies with a greater concentration of management ownership (and thus more risk-averse managers) avoid less tax.

Design/methodology/approach

The authors use a regression analysis with panel data, using as a sample of Brazilian companies from 2001 to 2015. The authors investigate the impact of insider ownership on tax avoidance, testing how and how much different ownership levels of inside owner are associated with tax avoidance measured by effective tax rates and book-tax differences.

Findings

The results indicate that different levels of management ownership are associated with different levels of tax avoidance behavior.

Originality/value

This paper contributes to the literature showing that ownership and decision making are not always focused on only a few decision makers. The owners are likely to be more risk averse and therefore less willing to invest in risky projects such as tax avoidance.
Intergenerational transmission of human capital
Authors: Uddin Md Nasir
Published: April 2019

Purpose

The purpose of this paper is to find the rate of intergenerational transmission of human capital and comparative schooling attainment between lower and higher income families using the labor force survey in Thailand.

Design/methodology/approach

Instrumental variable (IV) approach has been used in this paper. The author proposed an alternative instrument for parental education to identify the rate of transmission, which is the parents’ cohorts’ mean schooling in their respective provinces.

Findings

This paper found that the rate of transmission of human capital from father is higher than that from mother in Thailand. For both, the rate of transmission in Thailand is higher than that in the developed countries. In addition, it is found that children from lower income families are getting lesser education than those from higher income families in Thailand.

Research limitations/implications

This paper is used as an alternative instrument that could solve the endogeneity problem in the literature of intergenerational transmission of human capital.

Practical implications

The results of rate of transmission can help to make educational policies in countries like Thailand. It also could help the policymakers to evaluate and redesign the student loan scheme (SLS) in Thailand.

Originality/value

This study is used as an alternative instrument for parental education to identify the rate of transmission in an IV approach. This paper is the first to identify the intergenerational transmission rate in Thailand. In addition, it evaluates Thai SLS in an intergenerational framework.
The economic market outcomes and income distribution when capital is not homogeneous
Authors: Özçam Ahmet
Published: April 2019

Purpose

An aggregate production function has been used in macroeconomic analysis for a long time, even though it seems that it is conceptually confusing and problematic. The purpose of this paper is to argue that the measurement problem related to the heterogenous capital input that exists in macroeconomics is also relevant to microeconomic market situations.

Design/methodology/approach

The author constructed a microeconomic market model to address both the problems of the measurement of the physical capital and of substitutability between labor and capital in the short run using two types of technologies: labor neutral and labor reducing. The author proposed that labor and physical capital inputs are complementary in the short run and can become substitutes only in the long run when the technology advances.

Findings

The author found that even if the technology improves at a fast rate over time, there are then diminishing returns of profits to technology and an upper limit to profits. Moreover, the author showed that under the labor-reducing technology, labor class earns more initially as technology improves, but their incomes start declining after some threshold level of passage of time.

Originality/value

The author cautioned the applied researcher that the estimated labor and capital coefficients of generalized Cobb–Douglas and constant elasticity of substitution of types of production functions could not be interpreted as partial elasticities of labor and capital if in reality the data come from fixed-proportions types of processes.
Ranking factors influencing strategic management of university business incubators with ANP
Authors: Kiani Mavi Reza , Gheibdoust Hamed , Khanfar Ahmad A. , Kiani Mavi Neda
Published: April 2019

Purpose

Universities play a central role in scientific development and progress in societies, so, the need for supporting new businesses in universities becomes very important that science and technology park-based incubators can meet it. The purpose of this paper is to prioritize the factors influencing strategic management of university business incubators (UBIs).

Design/methodology/approach

Present research prioritizes the factors influencing strategic management of incubators using analytic network process (ANP). The authors gathered data from UBIs affiliated with science and technology park of Guilan, located in city of Rasht (Iran) using the ANP questionnaire during year 2017.

Findings

Factors influencing strategic management of incubators comprised of four main criteria and 14 sub-criteria. The criteria and sub-criteria were ranked based on their importance. Results show that “talented managers” has the highest importance for strategic management of UBIs.

Originality/value

This study offers a novel analysis and contribution to the knowledge of ranking UBIs with a multi-criteria decision-making technique. Results of this research show the relative importance of criteria and sub-criteria, which contributes to further improvement of incubator management. University managers and incubator directors can utilize the findings for better resource allocation and aligning the strategies of incubators with macro strategies of the country.
When is resemblance mimicry?
Authors: de Jager Marinus L. , Anderson Bruce
Published: April 2019

Mimetic resemblance is extensive across the tree of life yet agreeing on what constitutes mimicry is challenging. One of the reasons for disagreement is a lack of unambiguous criteria to resolve whether a case of resemblance is a product of mimicry or alternative processes.

Mimicry occurs when an organism takes advantage of the perception and association that a receiver has with a model to gain adaptive benefits. Three conditions should be fulfilled to confirm mimicry: (1) characterising a model, (2) identifying a receiver with a percept of said model and (3) demonstrating that the receiver exerts selection on the mimic.

We suggest multiple lines of evidence, both experimental and correlative, to support each condition. These conditions help separate similarity due to crypsis and perceptual bias from mimetic resemblance. Furthermore, we explore forms of receiver‐mediated selection on the mimic, what mimics need to resemble for successful mimicry to occur, and the evolution of imperfect mimicry.

We hope this perspective provides a functional pathway for biologists to confirm the existence of mimicry and serve as a guide for studying mimetic interactions across disciplines.

A free Plain Language Summary can be found within the Supporting Information of this article.
Mycorrhizal‐mediated plant–herbivore interactions in a high CO2 world
Authors: Frew Adam , Price Jodi N.
Published: April 2019

The symbiotic relationship between terrestrial plants and arbuscular mycorrhizal (AM) fungi is a key driver of plant nutritional and defence traits influencing insect herbivory. These tripartite interactions have been fundamental to shaping the evolution of land plants and the diversity of insect herbivores. Surprisingly, we have little understanding of how these interactions will function under elevated atmospheric CO2 concentrations (eCO2), despite the considerable implications for both natural and managed ecosystems.

Although substantial research has revealed how eCO2 alters mycorrhizal–plant interactions, or plant–herbivore interactions, there is a stark scarcity of studies which investigate how eCO2 impacts mycorrhizal‐mediated plant–insect herbivore relationships.

Here, we synthesise some of the main effects of eCO2 on the mycorrhizal symbiosis, the concomitant impacts on plant nutrient dynamics and secondary metabolism, and how eCO2‐driven changes in plant growth, biochemistry and communities impact insect herbivores.

We point out that potential mechanistic drivers of AM fungal–plant–insect herbivore relationships under eCO2 can function antagonistically and are highly context‐dependent, which poses a particular challenge. Still, we hypothesise as to the potential outcomes for AM fungal–plant–herbivore dynamics under eCO2.

We identify key research priorities to tackle the substantial gap in our understanding. If ecological theory is to effectively inform agricultural and natural management practices in the future, research needs to directly investigate how changes in global atmospheric CO2 concentrations impact the tripartite relationship between AM fungi, plants and insect herbivores.

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Costs and drivers of helminth parasite infection in wild female baboons
Authors: Akinyi Mercy Y. , Jansen David , Habig Bobby , Gesquiere Laurence R. , Alberts Susan C. , Archie Elizabeth A.
Published: April 2019

Helminth parasites can have wide‐ranging, detrimental effects on host reproduction and survival. These effects are best documented in humans and domestic animals, while only a few studies in wild mammals have identified both the forces that drive helminth infection risk and their costs to individual fitness.

Working in a well‐studied population of wild baboons (Papio cynocephalus) in the Amboseli ecosystem in Kenya, we pursued two goals, to (a) examine the costs of helminth infections in terms of female fertility and glucocorticoid hormone levels and (b) test how processes operating at multiple scales—from individual hosts to social groups and the population at large—work together to predict variation in female infection risk.

To accomplish these goals, we measured helminth parasite burdens in 745 faecal samples collected over 5 years from 122 female baboons. We combine these data with detailed observations of host environments, social behaviours, hormone levels and interbirth intervals (IBIs).

We found that helminths are costly to female fertility: females infected with more diverse parasite communities (i.e., higher parasite richness) exhibited longer IBIs than females infected by fewer parasite taxa. We also found that females exhibiting highTrichuris trichiuraegg counts also had high glucocorticoid levels. Female infection risk was best predicted by factors at the host, social group and population level: females facing the highest risk were old, socially isolated, living in dry conditions and infected with other helminths.

Our results provide an unusually holistic understanding of the factors that contribute to inter‐individual differences in parasite infection, and they contribute to just a handful of studies linking helminths to host fitness in wild mammals.
Critical predictors of functional, phylogenetic and taxonomic diversity are geographically structured in lichen epiphytic communities
Authors: Hurtado Pilar , Prieto María , Aragón Gregorio , Escudero Adrián , Martínez Isabel
Published: April 2019

Assessing the response of biological communities to contrasting environmental conditions is crucial to predict the effects of global change drivers. The influence of multiple environmental factors may differ depending on the diversity facet considered, which emphasizes the need to simultaneously evaluate the functional (FD), phylogenetic (PD) and taxonomic (TD) diversity.

To examine how these facets of biodiversity respond to environmental changes, we studied lichen epiphytic communities across 47 beech forest fragments from two biogeographic regions. We applied structural equation modelling to relate habitat fragmentation, climate and habitat quality with FD, PD and TD. We compared the community response to contrasting climatic conditions by analysing independently Atlantic and Mediterranean communities.

We found different major drivers of biodiversity patterns across biogeographic regions. Habitat fragmentation performed the highest effect on lichen communities, with a reduction of FD, PD and TD at both regions. However, the influence of climate was stronger in the Atlantic region than in the Mediterranean region, where the effect of habitat quality was superior. The effect of the environmental predictors over PD and TD was both direct and indirect through the different components of FD, and their intensity and sign differed across regions. Changes in PD were not related to changes in TD.

Synthesis. Our results evidenced that the major environmental drivers affecting epiphytic communities were geographically structured. These drivers modified the diversity of the epiphytic community directly but also indirectly through changes in FD, which emerged as a causal but not unique determinant of PD and TD. Our findings also showed the difficulty for inferring TD through PD. These results emphasize the essential role of FD predicting part of the response of lichen communities to global change drivers but also highlight the importance of considering multiple biodiversity facets to understand the effects of environmental change on community structure.
Modeling the effects of urban expansion on regional carbon storage by coupling SLEUTH‐3r model and InVEST model
Authors: Lyu Rongfang , Mi Lina , Zhang Jianming , Xu Mengqun , Li Jijun
Published: April 2019

Modeling the impacts of urbanization on carbon storage has become a critical and hot topic in the fields of mitigating global warming. This study coupled urban expansion and land use change simulation and prediction model (SLEUTH‐3r model) and ecosystem service evaluation model (InVEST model) to analyze and predict the impacts of urbanization on carbon storage in Shizuishan, a city located in the northwestern of China. Scenarios analysis was used to compare the effects of different policies on carbon storage, while the policies concern about urban growth pattern, ecological protection and socioeconomic development. The results suggested that (1) the coupled model can predict carbon storage change with urbanization in a high accuracy (relative error within ±5% for 94.6% of the whole area); (2) carbon storage of Shizuishan experienced a loss of 2.70 Tg in 1989–2015, and would continue to experience a loss of 6.18 Tg, 5.27 Tg, 3.76 Tg and 2.47 Tg under historical growth scenario (HGS), decrease socioeconomic scenario (DSS), compact growth scenario (CGS) and ecological protection scenario (EPS) in 2015–2035, respectively; (3) compact urban growth pattern and ecological protection policy can both decrease the negative effects of urbanization on carbon storage. Multiple ecosystem services should be integrated into urban planning to achieve a balance of socioeconomic development and environment protection.
Preferential utilization of inorganic polyphosphate over other bioavailable phosphorus sources by the model diatoms Thalassiosira spp.
Authors: Diaz Julia M. , Steffen Rachel , Sanders James G. , Tang Yuanzhi , Duhamel Solange
Published: April 2019

Polyphosphates and phosphomonoesters are dominant components of marine dissolved organic phosphorus (DOP). Collectively, DOP represents an important nutritional phosphorus (P) source for phytoplankton growth in the ocean, but the contribution of specific DOP sources to microbial community P demand is not fully understood. In a prior study, it was reported that inorganic polyphosphate was not bioavailable to the model diatoms Thalassiosira weissflogii and Thalassiosira pseudonana. However, in this study, we show that the previous finding was a misinterpretation based on a technical artefact of media preparation and that inorganic polyphosphate is actually widely bioavailable to Thalassiosira spp. In fact, orthophosphate, inorganic tripolyphosphate (3polyP), adenosine triphosphate (ATP) and adenosine monophosphate supported equivalent growth rates and final growth yields within each of four strains of Thalassiosira spp. However, enzyme activity assays revealed in all cultures that cell‐associated hydrolysis rates of 3polyP were typically more than ~10‐fold higher than degradation of ATP and the model phosphomonoester compound 4‐methylumbelliferyl phosphate. These results build on prior work, which showed the preferential utilization of polyphosphates in the cell‐free exudates of Thalassiosira spp., and suggest that inorganic polyphosphates may be a key bioavailable source of P for marine phytoplankton.
Effects of Milk Proteins on the Bioaccessibility and Antioxidant Activity of Oat Phenolics During In Vitro Digestion
Authors: Chen Chao , Wang Li , Chen Zhengxing , Luo Xiaohu , Li Yongfu , Wang Ren , Li Juan , Li Yanan , Wang Tao , Wu Jue
Published: April 2019

This study investigated the effects of milk solution or milk proteins (casein and whey protein) on the bioaccessibility and antioxidant activity of oat phenolics during in vitro gastric and pancreatic digestion. During digestion, most of oat phenolics were partially degraded by alkaline pH of pancreatic fluid (pH 7.5). For phenolic acids, both milk solution and milk protein only had a slight influence on their bioaccessibility, while exhibited a significant effect on antioxidant activity of oat phenolic extracts and bioaccessibility of avenanthramides (AVs), a kind of bioactive phenols exclusively found in oats. The antioxidant activity and bioaccessibility of AVs were decreased by adding milk and casein, while significantly improved when mixed with milk whey protein. Remarkably, the bioaccessibility of AV 2c, which had the highest antioxidant activity among all phenolic compounds detected in oats, increased above 360% after intestinal digestion by mixing with whey protein. This result suggested the possibility of protecting AVs against digestive alteration and oxidation by milk whey protein.

Practical Application

In recent years, oats are often consumed with milk under different conditions of preparation, and there have been many oat milk products manufactured by food companies all over the world. The results of this paper showed that the adding of milk may reduce the absorption and antioxidant activity of phenolic compounds from oat. However, the antioxidant activity and bioaccessibility of oat phenolics were significantly increased when mixed with milk whey protein, suggesting that oats could be consumed with milk whey protein to improve their functional properties.