bluuebunny/crossref_metadata_2025 huggingface dataset:
Polygenic adaptation of rosette growth inArabidopsis thaliana
Authors: Wieters Benedict , Steige Kim A. , He Fei , Koch Evan M. , Ramos-Onsins Sebastián E. , Gu Hongya , Guo Ya-Long , Sunyaev Shamil , de Meaux Juliette
Published: April 2020

The rate at which plants grow is a major functional trait in plant ecology. However, little is known about its evolution in natural populations. Here, we investigate evolutionary and environmental factors shaping variation in the growth rate ofArabidopsis thaliana. We used plant diameter as a proxy to monitor plant growth over time in environments that mimicked latitudinal differences in the intensity of natural light radiation, across a set of 278 genotypes sampled within four broad regions, including an outgroup set of genotypes from China. A field experiment conducted under natural conditions confirmed the ecological relevance of the observed variation. All genotypes markedly expanded their rosette diameter when the light supply was decreased, demonstrating that environmental plasticity is a predominant source of variation to adapt plant size to prevailing light conditions. Yet, we detected significant levels of genetic variation both in growth rate and growth plasticity. Genome-wide association studies revealed that only 2 single nucleotide polymorphisms associate with genetic variation for growth above Bonferroni confidence levels. However, marginally associated variants were significantly enriched among genes with an annotated role in growth and stress reactions. Polygenic scores computed from marginally associated variants confirmed the polygenic basis of growth variation. For both light regimes, phenotypic divergence between the most distantly related population (China) and the various regions in Europe is smaller than the variation observed within Europe, indicating that some level of stabilizing selection constrains the evolution of growth rate. We observed that Spanish genotypes, however, reach a significantly larger size than Northern European genotypes. Tests of adaptive divergence and analysis of the individual burden of deleterious mutations reveal that adaptive processes have played a more important role in shaping regional differences in rosette growth than maladaptive evolution.
EXPRESSION OFMycobacterium tuberculosisRpsA INMycobacterium smegmatisINCREASES SUSCEPTIBILITY TO PYRAZINAMIDE
Authors: Antiparra Ricardo , Santos Marco , Toledo Angie , Gilman Robert H. , Kirwan Daniela E. , Sheen Patricia , Zimic Mirko
Published: April 2020

Pyrazinamide (PZA) is one of the most important drugs used in combined antituberculous therapy. After the drug entersMycobacterium tuberculosisit is hydrolyzed by pyrazinamidase (PZAse) to the bactericidal molecule pyrazinoic acid (POA). Ribosomal protein S1 (RpsA) was recently identified as a possible target of PZA based on its binding activity to POA and capacity to inhibit trans-translation. However, its role is not completely understood.

It has been proposed thatMycobacterium smegmatisRpsA is not capable of binding POA, unlikeM. tuberculosisRpsA. This may be due to the different amino acid sequence in the carboxy-terminal region of the two molecules: inM. smegmatisRpsA it is much closer to the sites that may interact with POA than inM. tuberculosisRpsA. These differences could be contributing, along with the presence of highly active POA efflux, to the natural resistance to PZA inM. smegmatis.

To further understand the mechanisms of action of PZA and the role of RpsA in PZA susceptibility, we evaluated the effect of complementingM. tuberculosisRpsA expression inM. smegmatisusing pNIT mycobacterial non-integrative expression vector and then performed a PZA susceptibility test determining the minimum inhibitory concentration (MIC) of PZA. It was expected that chimeric ribosomes comprisingM. tuberculosisRpsA may be present and may affect PZA susceptibility.

Our results showed a reduction in PZA MIC inM. smegmatiscomplemented with overexpressedM. tuberculosisRpsA compared to non-overexpressedM. smegmatis(468 µg/mL and >7500 µg/mL respectively).
The effects of soil depth on the structure of microbial communities in agricultural soils in Iowa, USA
Authors: Hao Jingjie , Chai Yen Ning , Ordóñez Raziel A. , Wright Emily E. , Archontoulis Sotirios , Schachtman Daniel P.
Published: April 2020

The determination of how microbial community structure changes within the soil profile, will be beneficial to understanding the long-term health of agricultural soil ecosystems and will provide a first step towards elucidating how deep soil microbial communities contribute to carbon sequestration. This study aimed to investigate the differences in the microbial community abundance, composition and diversity throughout from the surface layers down to deep soils in corn and soybean fields in Iowa, USA. We used 16S rRNA amplicon sequencing of soil samples to characterize the change in microbial community structure. Our results revealed decreased richness and diversity in bacterial community structure with increasing soil depth. We also observed distinct distribution patterns of bacterial community composition along soil profiles. Soil and root data at different depths enabled us to demonstrate that the soil organic matter, soil bulk density and plant water availability were all significant factors in explaining the variation in soil microbial community composition. Our findings provide valuable insights in the changes in microbial community structure to depths of 180 cm in one of the most productive agricultural regions in the world. This knowledge will be important for future management and productivity of agroecosystems in the face of increasing demand for food and climate change.
Cortical stiffness of keratinocytes measured by lateral indentation with optical tweezers
Authors: Jokhadar Špela Zemljič , Stojković Biljana , Vidak Marko , Liovic Mirjana , Gouveia Marcos , Travasso Rui D.M. , Derganc Jure
Published: April 2020

Keratin intermediate filaments are the principal structural element of epithelial cells. Their importance in providing bulk cellular stiffness is well recognized, but their role in the mechanics of cell cortex is less understood. In this study, we therefore compared the cortical stiffness of three keratinocyte lines: primary wild type cells (NHEK2), immortalized wild type cells (NEB1) and immortalized mutant cells (KEB7). The cortical stiffness was measured by lateral indentation of cells with AOD-steered optical tweezers without employing any moving mechanical elements. The method was validated on fixed cells and Cytochalasin-D treated cells to ensure that the observed variations in stiffness within a single cell line were not a consequence of low measurement precision. The measurements of the cortical stiffness showed that primary wild type cells were significantly stiffer than immortalized wild type cells, which was also detected in previous studies of bulk elasticity. In addition, a small difference between the mutant and the wild type cells was detected, showing that mutation of keratin impacts also the cell cortex. Thus, our results indicate that the role of keratins in cortical stiffness is not negligible and call for further investigation of the mechanical interactions between keratins and elements of the cell cortex.
Conservation genomics reveals low genetic diversity and multiple parentage in the threatened freshwater mussel,Margaritifera hembeli
Authors: Garrison Nicole L. , Johnson Paul D. , Whelan Nathan V.
Published: April 2020

Margaritifera hembeliis a federally threatened freshwater mussel species restricted to three central Louisiana drainages. Currently, management efforts are being formulated without an understanding of population-level genetic patterns, which could result in sub-optimal conservation outcomes. In particular, information about riverscape genetic patterns is needed to design effective propagation and reintroduction plans. We apply a genomic approach (RADseq) to assess genetic diversity and structure among four wild populations sampled from across the species range. We also assess the genetic diversity of a captively reared cohort produced from a single female. We recovered population differentiation between individuals sampled to the north and south of the Red River. All sites had similarly low levels of heterogeneity and other measures of genetic diversity. The captive cohort displayed higher levels of genetic diversity than expected and likely represents a case of multiple paternity. Future propagation efforts will likely be able to produce genetically diverse cohorts from a small number of wild-caught females, and we recommend future reintroduction efforts utilize brooders within the sub-drainage closest to the reintroduction effort.
Staufen1 localizes to the mitotic spindle and controls the transport of RNA populations to the spindle
Authors: Hassine Sami , Bonnet-Magnaval Florence , Benoit-Bouvrette Louis-Philip , Doran Bellastrid , Ghram Mehdi , Bouthillette Mathieu , Lecuyer Eric , DesGroseillers Luc
Published: April 2020

Staufen1 (STAU1) is an RNA-binding protein involved in the posttranscriptional regulation of mRNAs. We report that a large fraction of STAU1 localizes to the mitotic spindle in the colorectal cancer HCT116 and in the non-transformed hTERT-RPE1 cells. Spindle-associated STAU1 partly co-localizes with ribosomes and active sites of translation. We mapped the molecular determinant required for STAU1/spindle association within the first 88 N-terminal amino acids, a domain that is not required for RNA binding. Interestingly, transcriptomic analysis of purified mitotic spindles reveals that 1054 mRNAs as well as the precursor ribosomal RNA and lncRNAs and snoRNAs involved in ribonucleoprotein assembly and processing are enriched on spindles compared to cell extracts. STAU1 knockout causes the displacement of the pre-rRNA and of 154 mRNAs coding for proteins involved in actin cytoskeleton organization and cell growth, highlighting a role for STAU1 in mRNA trafficking to spindle. These data demonstrate that STAU1 controls the localization of sub-populations of RNAs during mitosis and suggests a novel role of STAU1 in pre-rRNA maintenance during mitosis, ribogenesis and/or nucleoli reassembly.

SUMMARY STATEMENT

Proper localization and functions of macromolecules during cell division are crucial to ensure survival and proliferation of daughter cells.
iCellR: Combined Coverage Correction and Principal Component Alignment for Batch Alignment in Single-Cell Sequencing Analysis
Authors: Khodadadi-Jamayran Alireza , Pucella Joseph , Zhou Hua , Doudican Nicole , Carucci John , Heguy Adriana , Reizis Boris , Tsirigos Aristotelis
Published: April 2020

Under-sampling RNA molecules and low-coverage sequencing in some single cell sequencing technologies introduce zero counts (also known as drop-outs) into the expression matrices. This issue may complicate the processes of dimensionality reduction and clustering, often forcing distinct cell types to falsely resemble one another, while eliminating subtle, but important differences. Considering the wide range in drop-out rates from different sequencing technologies, it can also affect the analysis at the time of batch/sample alignment and other downstream analyses. Therefore, generating an additional harmonized gene expression matrix is important. To address this, we introduce two separate batch alignment methods: Combined Coverage Correction Alignment (CCCA) and Combined Principal Component Alignment (CPCA). The first method uses a coverage correction approach (analogous to imputation) in a combined or joint fashion between multiple samples for batch alignment, while also correcting for drop-outs in a harmonious way. The second method (CPCA) skips the coverage correction step and uses k nearest neighbors (KNN) for aligning the PCs from the nearest neighboring cells in multiple samples. Our results of nine scRNA-seq PBMC samples from different batches and technologies shows the effectiveness of both these methods. All of our algorithms are implemented in R, deposited into CRAN, and available in the iCellR package.
A trimeric autotransporter enhances biofilm cohesiveness inYersinia pseudotuberculosisbut not inYersinia pestis
Authors: Calder Joshua T. , Christman Nicholas D. , Hawkins Jessica M. , Erickson David L.
Published: April 2020

Cohesion of biofilms made byYersinia pestisandYersinia pseudotuberculosis(Yptb) has been attributed solely to an extracellular polysaccharide matrix encoded by thehmsgenes (Hms-ECM). However, mutations in theYptbBarA/UvrY/CsrB regulatory cascade enhance biofilm stability without dramatically increasing Hms-ECM production. We found that treatment with proteinase K enzyme effectively destabilizedYptb csrBmutant biofilms, suggesting that cell-cell interactions might be mediated by protein adhesins or extracellular matrix proteins. We identified an uncharacterized trimeric autotransporter lipoprotein (YPTB2394), repressed bycsrB, which has been referred to as YadE. Biofilms made by a ΔyadEmutant strain were extremely sensitive to mechanical disruption. Overexpression ofyadEin wild-typeYptbincreased biofilm cohesion, similar to biofilms made bycsrBoruvrYmutants. We found that the Rcs signaling cascade, which represses Hms-ECM production, activated expression ofyadE. TheyadEgene appears to be functional inYptbbut is a pseudogene in modernY. pestis strains. Expression of functionalyadEinY. pestisKIM6+ altered the production of Hms-ECM and weakened biofilms made by these bacteria. This suggests that although the YadE autotransporter protein increasesYptbbiofilm stability, it may be incompatible with Hms-ECM production that is essential forY. pestisbiofilm production in fleas. Inactivation ofyadEinY. pestismay be another instance of selective gene loss in the evolution of flea-borne transmission by this species.

IMPORTANCE

The evolution ofYersinia pestisfrom itsY. pseudotuberculosis(Yptb) ancestor involved gene acquisition and gene losses, leading to differences in biofilm production. Characterizing the unique biofilm features of both species may provide better understanding of how each adapts to its specific niches. This study identifies a trimeric autotransporter YadE that promotes biofilm stability ofYptbbut which has been inactivated inY. pestis, likely because it is not compatible with Hms polysaccharide that is crucial for biofilms inside fleas. We also reveal that the Rcs signaling cascade, which represses Hms expression inY. pestis, activates YadE inYptb. The ability ofYptbto use polysaccharide or YadE protein for cell-cell adhesion may help it produce biofilms in different environments.
Two-Step Bacterial Artificial Chromosome (BAC) Engineering: Preparation of the A Homology Arm (A-Box) and B Homology Arm (B-Box)
Authors: Heintz Nathaniel , Gong Shiaoching
Published: April 2020

The 700-bp A homology arm (A-box) and the 700-bp B homology arm (B-box) are amplified by polymerase chain reaction (PCR) using purified bacterial artificial chromosome (BAC) DNA as template for two-step BAC engineering. The resulting A-box PCR product contains an AscI site at its 5′ end (the 5′ primer incorporates an AscI site, and the 3′ primer does not incorporate any restriction sites). The B-box PCR product contains an XmaI site at its 3′ end (the 5′ primer does not incorporate any restriction sites, and the 3′ primer incorporates an XmaI site). The amplification products are then digested with the appropriate restriction endonucleases to render them suitable for cloning into the shuttle vector.
Two-Step Bacterial Artificial Chromosome (BAC) Engineering: Cloning of the A and B Homology Arms into the Shuttle Vector
Authors: Heintz Nathaniel , Gong Shiaoching
Published: April 2020

This protocol describes the preparation of the shuttle vector before its introduction into bacterial artificial chromosome (BAC) host cells for BAC two-step engineering. The homology arm sequences, prepared previously, are introduced by ligation into the digested shuttle vector DNA to provide sites for recombination within the BAC clone. Crude lysates of individual bacterial transformants serve as templates in polymerase chain reaction (PCR) analysis to confirm the presence of the homology arms in the recombinant shuttle vector.
Strong hydrogen bonding in a dense hydrous magnesium silicate discovered by neutron Laue diffraction
Authors: Purevjav Narangoo , Okuchi Takuo , Hoffmann Christina
Published: April 2020

A large amount of hydrogen circulates inside the Earth, which affects the long-term evolution of the planet. The majority of this hydrogen is stored in deep Earth within the crystal structures of dense minerals that are thermodynamically stable at high pressures and temperatures. To understand the reason for their stability under such extreme conditions, the chemical bonding geometry and cation exchange mechanism for including hydrogen were analyzed in a representative structure of such minerals (i.e. phase E of dense hydrous magnesium silicate) by using time-of-flight single-crystal neutron Laue diffraction. Phase E has a layered structure belonging to the space group R
3
m and a very large hydrogen capacity (up to 18% H2O weight fraction). It is stable at pressures of 13–18 GPa and temperatures of up to at least 1573 K. Deuterated high-quality crystals with the chemical formula Mg2.28Si1.32D2.15O6 were synthesized under the relevant high-pressure and high-temperature conditions. The nuclear density distribution obtained by neutron diffraction indicated that the O—D dipoles were directed towards neighboring O2− ions to form strong interlayer hydrogen bonds. This bonding plays a crucial role in stabilizing hydrogen within the mineral structure under such high-pressure and high-temperature conditions. It is considered that cation exchange occurs among Mg2+, D+ and Si4+ within this structure, making the hydrogen capacity flexible.
Ion permeation in potassium ion channels
Authors: Coates Leighton
Published: April 2020

The study of ion channels dates back to the 1950s and the groundbreaking electrophysiology work of Hodgin and Huxley, who used giant squid axons to probe how action potentials in neurons were initiated and propagated. More recently, several experiments using different structural biology techniques and approaches have been conducted to try to understand how potassium ions permeate through the selectivity filter of potassium ion channels. Two mechanisms of permeation have been proposed, and each of the two mechanisms is supported by different experiments. The key structural biology experiments conducted so far to try to understand how ion permeation takes place in potassium ion channels are reviewed and discussed. Protein crystallography has made, and continues to make, key contributions in this field, often through the use of anomalous scattering. Other structural biology techniques used to study the contents of the selectivity filter include solid-state nuclear magnetic resonance and two-dimensional infrared spectroscopy, both of which make clever use of isotopic labeling techniques, while molecular-dynamics simulations of ion flow through the selectivity filter have been enabled by the growing number of potassium ion channel structures deposited in the Protein Data Bank.
Transformational leadership and employee efficiency: knowledge sharing as mediator
Authors: Dwivedi Preeti , Chaturvedi Vijit , Vashist Jugal Kishore
Published: April 2020

Purpose

This research aims to examine the influence of transformational leadership on employee efficiency. The research also examines the role of knowledge sharing as a mediator between transformational leadership and employee efficiency.

Design/methodology/approach

The research is based on the survey conducted among 200 employees of logistics firms. Exploratory Factor analysis (EFA) and Confirmatory Factor Analysis (CFA) approaches are used for the evaluation.

Findings

The study found that transformational leadership has positive and significant influence on employee efficiency. The research also demonstrates that after introducing knowledge sharing, it fully mediated the influence of transformational leadership on employee efficiency. The study suggests that, if leaders share their knowledge and expertise among the team, employees have a propensity to be highly effective and efficient than without knowledge sharing.

Research limitations/implications

Blue collar staff and unskilled labors of the firms are not included in the study. So, the study is limited to white collar staff only which can further be expanded by considering other ground staff. Also few or no such researches have been conducted in logistics firms, particularly in Indian logistics firms. So, the result of this study can be used as reference to explore the area. This study can be replicated in the logistics firms of other regions also.

Practical implications

The finding of the study will help the top management of the organizations to formulate strategies to enhance its senior-subordinate relationship through knowledge sharing. The study also suggests that regular dissemination of knowledge among the team improves the efficiency of the team members and hence the performance of the organization.

Originality/value

This research examines the degree to which knowledge sharing acts as a mediator between transformational leadership and employee efficiency, which has not been found in previous studies.
Perceptions of the effectiveness of health care for probationers
Authors: Sirdifield Coral , Marples Rebecca , Denney David , Brooker Charlie
Published: April 2020

Purpose

This study aims to investigate the views of commissioners, providers and criminal justice staff on how effective current health-care provision is at meeting the health needs of people on probation. Understanding perceptions of what constitutes effective provision, where barriers are encountered and where improvements could be made is an important step towards improving access to care for this hard-to-reach group.

Design/methodology/approach

The research was part of a wider study. This paper focusses on findings from case studies conducted via semi-structured telephone interviews with 24 stakeholders in a purposive sample from six geographical areas of England. Interviews were conducted by researchers from a variety of backgrounds and an individual with lived experience of the criminal justice system. Data were analysed using thematic analysis.

Findings

Participants provided examples of effective health-care provision, which largely involved multi-agency partnership working. It was apparent that there are many barriers to providing appropriate health-care provision to people on probation, which are underpinned by the complexity of this population’s health-care needs, the complexity of the health-care landscape and problematic commissioning processes.

Practical implications

Improvements are needed to provide appropriate and accessible health care that meets the needs of people on probation, thereby reducing health inequalities. These include shared targets, improved funding, clearer pathways into care and giving probation a voice in commissioning.

Originality/value

To the best of authors’ knowledge, this is the first study of commissioner, provider and criminal justice staffs’ views on the effectiveness of current health-care provision at meeting the health needs of people on probation.
How relational drivers affect relationship value in key exporter-importer relationships: a dark side perspective
Authors: Miocevic Dario
Published: April 2020

Purpose

B2B marketing scholarship has acknowledged that relational capital and relationship-specific investments (RSIs) are critical relational drivers for explaining the success of business relationships, especially those in an export-import (E-I) context. However, the literature is still inconclusive on whether E-I partners should accentuate relational drivers to the fullest in order to increase relationship value. By drawing on relational view of competitive advantage and literature that explored the dark side of business relationships, the author builds a conceptual model exploring the boundary conditions (historical ties and relational capabilities) upon which relational drivers enhance or diminish relationship value in key E-I relationships.

Design/methodology/approach

To test the proposed model, a survey was conducted among 114 industrial exporters from Croatia. The data was analyzed with the use of confirmatory factor analysis and hierarchical regression.

Findings

This study contributes to the international B2B literature in two ways. First, the findings show that in the case of strong historical ties between E-I partners, relational capital has an inverted U-shape association with the relationship value, whereas in the case of weak historical ties this relationship becomes linear. Second, the findings show that an importer’s RSI will lead to the highest relationship value when an exporter reciprocates through employing relational capabilities through which the exporter adapts his business model to the needs of the importer. In case of an exporter’s weak relational capabilities, the relationship between an importer’s RSIs and the relationship value flips into an inverted U-shape.

Originality/value

This study extends the literature on dark side of business relationships by offering insights into the boundary conditions that are essential for sustaining the relationship value in key E-I relationships. The study reveals that historical ties and relational capabilities represent boundary conditions that offer a more detailed explanation what is the optimal configuration of relational drives that would increase the relationship value between key E-I partners.
Why is everything old new again? Revisiting debates about the form and function of research in educational administration
Authors: Donmoyer Robert
Published: April 2020

Purpose

This paper has a twofold purpose: (1) to demonstrate, largely with historical evidence, that, contrary to what some have argued, thinking about educational research articulated at the start of the twenty-first century was not really “new wine in new bottles” but, rather, a continuation of the so-called paradigm wars about, ultimately, unresolvable methodological and epistemological issues that occurred during the twentieth century; (2) to suggest a way members of the educational administration field might transcend, or at least circumvent, time-consuming and distracting battles about unresolvable methodological and epistemological issues in the future while keeping their focus on issues of practice.

Design/methodology/approach

This is a quasi-historical essay that uses influential literature during the historical periods focused on as evidence to support the essay's arguments.

Findings

The paper demonstrates that twentieth century philosophical disagreements about research methods and the role that educational research can play in policy and practice decision making were not resolved but, rather, were largely reenacted during the first decade of the twenty-first century, again without a resolution. The paper proposes a way that administrators, policymakers and researchers can manage this situation and still use research to make policy and practice decisions.

Practical implications

The paper suggests a new role for both school administrators and policymakers to play. If administrators/policymakers play this role successfully, all types of research can inform decision making about policy and practice, and researchers can concentrate on doing their research rather than engaging in unresolvable philosophical disputes.

Originality/value

Although a great deal has been written about the twentieth century's theory movement and paradigm wars and the twenty-first century's so-called science wars, the link between these phenomena has not been discussed in the literature. In addition, there have been few attempts to articulate an operational strategy for managing unresolvable philosophical disputes about research methods and the role that research can play in decision making. This paper tackles both matters.
Family firms’ sustainable longevity: the role of family involvement in business and innovation capability
Authors: Ahmad Shabir , Omar Rosmini , Quoquab Farzana
Published: April 2020

Purpose

The objective of this research is to investigate the influence of family involvement in business and innovation capability on sustainable longevity of family firms.

Design/methodology/approach

Data collected from 553 executives of 200 family firms that survived to the second generation and beyond was analyzed using partial least square (PLS) approach of structural equation modeling (SEM) to test the hypotheses and validate the model.

Findings

The results provided evidence of the significant influence of family involvement in business on sustainable longevity of family firms and partial mediation of innovation capability between family involvement in business and corporate sustainable longevity.

Research limitations/implications

The sample included family firms owned and governed by the owner family. The future researchers may focus on professionally managed or publicly listed family firms.

Practical implications

The path to family firms' sustainable longevity goes through innovation capability apart from effective family control, succession, commitment to the business and family enrichment. That requires the family firm to be proactive in innovation capability.

Originality/value

Family firms are the dominant form of business representing around 80% of global business structure that strives for survival and consistently pursues sustainable longevity strategies. In the current globally competitive environment, innovation capability has become a matter of life and death for any firm. Based on the transaction cost economics (TCE) theory of family firms, this study proposes an integrative model of sustainable longevity for family firms.
Organization theory in humanitarian operations: a review and suggested research agenda
Authors: Prakash Chandra , Besiou Maria , Charan Parikshit , Gupta Sumeet
Published: April 2020

Purpose

The purpose of this paper is to review the current application of organization theory (OT) in the humanitarian supply chain (HSC) and identify the future OT-based research opportunities that can advance knowledge of humanitarian operations.

Design/methodology/approach

The study uses a systematic literature review methodology to identify the current status and future direction of the OT-based study in HSC literature. The applied theories are those that have been mentioned in at least two research articles in the HSC literature. The proposed theories are either adopted from the top four referred organizational theories in the supply chain literature or those that can explain the issue of information asymmetry in HSC.

Findings

The study identifies and describes eight organizational theories and their possible future research questions in HSC. Among these, the first four theories (i.e. resource-based theory, resource dependence theory, social exchange theory and contingency theory) have already been initially applied in the humanitarian field, while the remaining theories (i.e. institutional theory, stakeholder theory, transactional cost theory and information theory) have potential for future application.

Research limitations/implications

The reviewed literature is limited to peer-reviewed journals listed in Thomson Reuters’ journal citation reports.

Practical implications

This study may help future researchers better understand and solve, using organizational theory, the behavioral challenges faced by humanitarian operations.

Originality/value

The study presents current applications of and future prospects for OT-based research in HSC, effectively providing the first review of OT applications in this area. The novel framework and new theories proposed herein may enable fresh directions for HSC research.
Self-efficacy as a resource: a moderated mediation model of transformational leadership, extent of change and reactions to change
Authors: Bayraktar Secil , Jiménez Alfredo
Published: April 2020

Purpose

Drawing from conservation of resources (COR) theory, this study empirically tests the impact of transformational leadership on commitment to and intention to support organizational change, proposing self-efficacy as a mediating mechanism. This study also aims to study whether the extent of change in the organization moderates the proposed relationship between transformational leadership, self-efficacy and change reactions.

Design/methodology/approach

A survey was conducted with a sample of 298 employees going through a major organizational change. The proposed moderated mediation relationship was tested by using PROCESS macro.

Findings

The findings showed that self-efficacy mediated the relationship between transformational leadership and reactions to change. Moreover, the extent of changes experienced by the employees moderated the relationship between self-efficacy and outcome variables. In other words, in high change contexts, self-efficacy appeared as a more salient and instrumental resource leading to positive reactions.

Practical implications

The results guide change managers to display a transformational leadership style to enhance self-efficacy of change recipients to generate positive attitudes and behaviors during change. Also, this study shows that self-efficacy particularly gains importance when the extent of change is high.

Originality/value

This study makes several important contributions to the organizational change literature. First, it shows that leaders play a crucial role in generating resources that enhance employees' positive reactions to change. Second, the conditional factor of the extent of change has not received much attention in the literature. This study raises attention to the fact that the importance of such resources may differ across low versus high extent of change contexts.
Does extracorporeal membrane oxygenation attenuate hypoxic pulmonary vasoconstriction in a porcine model of global alveolar hypoxia?
Authors: Holzgraefe Bernhard , Larsson Anders , Eksborg Staffan , Kalzén Håkan
Published: April 2020

Background

During severe respiratory failure, hypoxic pulmonary vasoconstriction (HPV) is partly suppressed, but may still play a role in increasing pulmonary vascular resistance (PVR). Experimental studies suggest that the degree of HPV during severe respiratory failure is dependent on pulmonary oxygen tension (PvO2). Therefore, it has been suggested that increasing PvO2 by veno‐venous extracorporeal membrane oxygenation (V‐V ECMO) would adequately reduce PVR in V‐V ECMO patients.

Objective

Whether increased PvO2 by V‐V ECMO decreases PVR in global alveolar hypoxia.

Methods

Nine landrace pigs were ventilated with a mixture of oxygen and nitrogen. After 15 minutes of stable ventilation and hemodynamics, the animals were cannulated for V‐V ECMO. Starting with alveolar normoxia, the fraction of inspiratory oxygen (FIO2) was stepwise reduced to establish different degrees of alveolar hypoxia. PvO2 was increased by V‐V ECMO.

Results

V‐V ECMO decreased PVR (from 5.5 [4.5‐7.1] to 3.4 [2.6‐3.9] mm Hg L−1 min, P = .006) (median (interquartile range),) during ventilation with FIO2 of 0.15. At lower FIO2, PVR increased; at FIO2 0.10 to 4.9 [4.2‐7.0], P = .036, at FIO2 0.05 to 6.0 [4.3‐8.6], P = .002, and at FIO2 0 to 5.4 [3.5 ‐ 7.0] mm Hg L−1 min, P = .05.

Conclusions

The effect of increased PvO2 by V‐V ECMO on PVR depended highly on the degree of alveolar hypoxia. Our results partly explain why V‐V ECMO does not always reduce right ventricular afterload at severe alveolar hypoxia.
Livestock browsing affects the species composition and structure of cloud forest in the Dhofar Mountains of Oman
Authors: Ball Lawrence , Tzanopoulos Joseph
Published: April 2020

Questions

It is frequently reported that overstocking of camels, cattle and goats is degrading the Anogeissus cloud forest, which is endemic to a 200‐km stretch of coastal mountains in southern Arabia. However, livestock impacts on the vegetation have not been assessed. Furthermore, we have a limited understanding of the impacts of large‐bodied browsing livestock, such as camels, in woodland and forest rangelands. Therefore, in this study, we examine the effects of livestock browsing on the species composition, density, and phytomorphology of woody vegetation in the Anogeissus cloud forests in the Dhofar Mountains of Oman.

Location

Data were collected at 30 sites in the Jabal Qamar mountain range in western Dhofar, Oman.

Methods

The point‐centred quarter method was used to sample the composition, density and structure of woody vegetation. Constrained correspondence analysis was used to quantify the effects of livestock browsing on woody plant species composition, whilst effects on plant density were analysed using mixed‐effects models. Standardised major axis regression was used to examine differences in height–diameter allometry (stunting) under different stocking rates.

Results

Fog density, topographic position and long‐term stocking rates were found to be important factors affecting woody species composition. We found lower species diversity and plant density, and higher frequencies of unpalatable species, under higher stocking rates. Juveniles showed a stronger response to stocking rates than adults, and several common species exhibited stunted morphology under high stocking rates.

Conclusions

Browsing by large‐bodied livestock, such as camels and cattle, can substantially alter the species composition, structure, and phytomorphology of woody vegetation in semi‐arid woodlands and forests. Juveniles are particularly susceptible to browsing which alters woody vegetation demography and inhibits regeneration potential. Our results support previous suggestions of overstocking in Dhofar and highlight the importance of swift measures to reduce livestock browsing pressure in the Anogeissus cloud forests.
Polygalasaponin F inhibits neuronal apoptosis induced by oxygen‐glucose deprivation and reoxygenation through the PI3K/Akt pathway
Authors: Xie Wei , Wulin Hade , Shao Guo , Wei Liqin , Qi Ruifang , Ma Baohui , Chen Naihong , Shi Ruili
Published: April 2020

Cerebral ischaemia is a common cerebrovascular disease and often induces neuronal apoptosis, leading to brain damage. Polygalasaponin F (PGSF) is one of the components in Polygala japonica Houtt, and it is a triterpenoid saponin monomer. This research focused on anti‐apoptotic effect of PGSF during oxygen‐glucose deprivation and reoxygenation (OGD/R) injury in rat adrenal pheochromocytoma cells (PC12) and primary rat cortical neurons. OGD/R treatment reduced viability of PC12 cells and primary neurons. This reduced viability was prevented by PGSF, as shown by MTT assay. OGD/R insult decreased expression of Bcl‐2/Bax both in PC12 cells and primary neurons but elevated levels of caspase‐3 in primary neurons. However, PGSF may up‐regulate expression of Bcl‐2/Bax and down‐regulate caspase‐3 in these particular cells. Furthermore, Bcl‐2/Bax and the ratio between phosphorylated Akt and total Akt were decreased in PC12 cells treated with OGD/R, and both were increased by PGSF. Moreover, increase in the ratios of Bcl‐2/Bax and phosphorylated Akt/total Akt in PC12 cells was suppressed by phosphatidylinositol 3‐kinase (PI3K) inhibitor. Data suggest PGSF might prevent OGD/R‐induced injury via activation of PI3K/Akt signalling. The ability of PGSF to block the effects of OGD/R appears to involve regulation of Bcl‐2, Bax and caspase‐3, which are related to apoptosis.
Does Modernizing Union Administrative Practices Promote or Hinder Union Revitalization? A Comparative Study of US, UK and Australian Unions
Authors: Clark Paul F. , Bamber Greg J. , Whitehead Paul V. , Gray Lois S. , Cockfield Sandra , Gilbert Kay
Published: April 2020

Can a union be both democratic and administratively efficient, or are these goals always at odds? Building on the Webbs’ focus on this critical question, this article analyses and compares the changing administrative policies and practices of US, UK and Australian trade unions over a 25‐year period. We conducted surveys of unions in all three countries to gather information on union policies and practices involving the unions’ human resources, hiring, budgeting and strategic planning. Using these novel longitudinal data, we contribute to industrial relations scholarship by showing that unions have increasingly adopted formal, systematic practices in these areas. The article is grounded in theory and also has practical relevance given the important implications that our findings may have for the revitalization of unions in the three countries and beyond.
Infrasonic hearing in birds: a review of audiometry and hypothesized structure–function relationships
Authors: Zeyl Jeffrey N. , den Ouden Olivier , Köppl Christine , Assink Jelle , Christensen‐Dalsgaard Jakob , Patrick Samantha C. , Clusella‐Trullas Susana
Published: April 2020

The perception of airborne infrasound (sounds below 20 Hz, inaudible to humans except at very high levels) has been documented in a handful of mammals and birds. While animals that produce vocalizations with infrasonic components (e.g. elephants) present conspicuous examples of potential use of infrasound in the context of communication, the extent to which airborne infrasound perception exists among terrestrial animals is unclear. Given that most infrasound in the environment arises from geophysical sources, many of which could be ecologically relevant, communication might not be the only use of infrasound by animals. Therefore, infrasound perception could be more common than currently realized. At least three bird species, each of which do not communicate using infrasound, are capable of detecting infrasound, but the associated auditory mechanisms are not well understood. Here we combine an evaluation of hearing measurements with anatomical observations to propose and evaluate hypotheses supporting avian infrasound detection. Environmental infrasound is mixed with non‐acoustic pressure fluctuations that also occur at infrasonic frequencies. The ear can detect such non‐acoustic pressure perturbations and therefore, distinguishing responses to infrasound from responses to non‐acoustic perturbations presents a great challenge. Our review shows that infrasound could stimulate the ear through the middle ear (tympanic) route and by extratympanic routes bypassing the middle ear. While vibration velocities of the middle ear decline towards infrasonic frequencies, whole‐body vibrations – which are normally much lower amplitude than that those of the middle ear in the ‘audible’ range (i.e. >20 Hz) – do not exhibit a similar decline and therefore may reach vibration magnitudes comparable to the middle ear at infrasonic frequencies. Low stiffness in the middle and inner ear is expected to aid infrasound transmission. In the middle ear, this could be achieved by large air cavities in the skull connected to the middle ear and low stiffness of middle ear structures; in the inner ear, the stiffness of round windows and cochlear partitions are key factors. Within the inner ear, the sizes of the helicotrema and cochlear aqueduct are expected to play important roles in shunting low‐frequency vibrations away from low‐frequency hair‐cell sensors in the cochlea. The basilar papilla, the auditory organ in birds, responds to infrasound in some species, and in pigeons, infrasonic‐sensitive neurons were traced back to the apical, abneural end of the basilar papilla. Vestibular organs and the paratympanic organ, a hair cell organ outside of the inner ear, are additional untested candidates for infrasound detection in birds. In summary, this review brings together evidence to create a hypothetical framework for infrasonic hearing mechanisms in birds and other animals.
Coalescing investments in school mental health in South Carolina
Authors: Shapiro Cheri J. , Collins Courtnie , Parker Jennifer , Martinez Samantha , Olson Stacey , Weist Mark D.
Published: April 2020

Background

Improving child and adolescent mental health requires states and jurisdictions to invest in school mental health efforts. In recent years, there has been notable expansion and improvement in school mental health services in the state of South Carolina related to a number of investments that are cumulatively promoting capacity building.

Methods

This narrative overview examines the history of the school mental health movement in one southern state and details efforts by multiple key stakeholders that have coalesced to form a strong system for advancing school mental health.

Results

Resting on a strong university–community partnership, five separate initiatives are described that together provide enhanced workforce training and support and expansion of school mental health services. Themes of this work are identified with a goal of supporting and advancing the development of school mental health systems in the United States.

Conclusion

Strong collaborations and communication efforts both within the university setting and between partners in education and community settings, along with engaged funders keen to enhance well‐being of children, youth, and families statewide have set the stage for the growth and expansion of school mental health services.
Self or (M)other? Infants’ Sensitivity to Bodily Overlap With Their Mother Reflects Their Dyadic Coordination
Authors: Maister Lara , Hodossy Lilla , Tsakiris Manos , Shinskey Jeanne L.
Published: April 2020

Adults experience greater self‐other bodily overlap in romantic than platonic relationships. One of the closest relationships is between mother and infant, yet little is known about their mutual bodily representations. This study measured infants’ sensitivity to bodily overlap with their mother. Twenty‐one 6‐ to 8‐month‐olds watched their mother’s face or a stranger’s face being stroked synchronously versus asynchronously with their own face. Infants preferred synchrony only when viewing their mother, not when viewing the stranger. Infants who strongly preferred synchrony with their mother also experienced less coordination with her in naturalistic interactions. Infants thus appear sensitive to bodily overlap with their mother, and this overlap reflects dyadic coordination, supporting theoretical accounts of intersubjectivity in the development of the bodily self.
Parenting stress as a mediator in the oral health of children and adolescents: A stress process model
Authors: Gazzaz Arwa Z. , Carpiano Richard M. , Aleksejuniene Jolanta
Published: April 2020

Objectives

We tested hypotheses regarding socioeconomic status (SES) disparities in oral health amongst children and adolescents and the extent to which such SES disparities may be mediated by parenting stress.

Methods

We analysed data from the 2011/2012 US National Survey of Children's Health for ages 6‐11 years (n = 21 596) and 12‐17 years (n = 23 584). Our models estimated associations between SES indicators (family income and parental education) and parenting stress with two oral health outcomes: parent‐reported child oral health and preventive dental visits.

Results

For both age groups, SES was positively associated with both oral health outcomes. Parenting stress mediated the relationship between SES and child oral health, not preventive dental visits—such that lower SES was associated with worse oral health via higher parenting stress. Amongst children, the indirect effect of parenting stress was observed for parental education and family income, whilst amongst adolescents, no indirect effect of parenting stress was observed.

Conclusion

Parenting stress was an important determinant of children's oral health and partially explained the SES‐related oral health disparities in children. Future research is needed to explore the causal pathways in this association.