bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathologies of Between-Groups Principal Components Analysis in Geometric Morphometrics
Authors: Bookstein Fred L.
Published: May 2019

Good empirical applications of geometric morphometrics (GMM) typically involve several times more variables than specimens, a situation the statistician refers to as “highp/n,” wherepis the count of variables andnthe count of specimens. This note calls your attention to two predictable catastrophic failures of one particular multivariate statistical technique, between-groups principal components analysis (bgPCA), in this high-p/nsetting. The more obvious pathology is this: when applied to the patternless (null) model ofpidentically distributed Gaussians over groups of the same size, both bgPCA and its algebraic equivalent, partial least squares (PLS) analysis against group, necessarily generate the appearance of huge equilateral group separations that are actually fictitious (absent from the statistical model). When specimen counts by group vary greatly or when any group includes fewer than about ten specimens, an even worse failure of the technique obtains: the smaller the group, the more likely a bgPCA is to fictitiously identify that group as the end-member of one of its derived axes. For these two reasons, when used in GMM and other high-p/nsettings the bgPCA method very often leads to invalid or insecure bioscientific inferences. This paper demonstrates and quantifies these and other pathological outcomes both for patternless models and for models with one or two valid factors, then offers suggestions for how GMM practitioners should protect themselves against the consequences for inference of these lamentably predictable misrepresentations. The bgPCA method should never be used unskeptically — it is never authoritative — and whenever it appears in partial support of any biological inference it must be accompanied by a wide range of diagnostic plots and other challenges, many of which are presented here for the first time.
Proximity labeling of protein complexes and cell type-specific organellar proteomes in Arabidopsis enabled by TurboID
Authors: Mair Andrea , Xu Shou-Ling , Branon Tess C. , Ting Alice Y. , Bergmann Dominique C.
Published: May 2019

Defining specific protein interactions and spatially or temporally restricted local proteomes improves our understanding of all cellular processes, but obtaining such data is challenging, especially for rare proteins, cell types, or events. Proximity labeling enables discovery of protein neighborhoods defining functional complexes and/or organellar protein compositions. Recent technological improvements, namely two highly active biotin ligase variants (TurboID and miniTurboID), allowed us to address two challenging questions in plants: (1) what are in vivo partners of a low abundant key developmental transcription factor and (2) what is the nuclear proteome of a rare cell type? Proteins identified with FAMA-TurboID include known interactors of this stomatal transcription factor and novel proteins that could facilitate its activator and repressor functions. Directing TurboID to stomatal nuclei enabled purification of cell type- and subcellular compartment-specific proteins. Broad tests of TurboID and miniTurboID in Arabidopsis and N. benthamiana and versatile vectors enable customization by plant researchers.
FACS-based isolation and RNA extraction of Secondary Cells from the Drosophila male Accessory Gland
Authors: Immarigeon Clément , Karch François , Maeda Robert K.
Published: May 2019

To appreciate the function of an organ, it is often critical to understand the role of rare cell populations. Unfortunately, this rarity often makes it difficult to obtain material for study. This is the case for the Drosophila male accessory gland, the functional homolog of mammalian prostate and seminal vesicle. In Drosophila, this gland is made up of two morphologically distinct cell types: the polygonally-shaped main cells, which compose 96% of the organ, and the larger, vacuole-containing secondary cells (SCs), which represent the remaining 4% of cells (~40 cells per lobe). Both cell types are known to produce accessory gland proteins (Acps), which are important components of the seminal fluid and are responsible for triggering multiple physiological and behavioral processes in females, collectively called the post-mating response (PMR). While a few genes are known to be specific to the SCs, the relative rarity of SCs has hindered the study of their whole transcriptome. Here, a method allowing for the isolation of SCs is presented, enabling the extraction and sequencing of RNAs from this rare cell population. The protocol consists of dissection, protease digestion and mechanical dissociation of the glands to obtain individual cells. Then, the cells are sorted by FACS, and living GFP-expressing SC singulets are isolated for RNA extraction. This procedure is able to provide SC-specific RNAs from ~40 males per condition in the course of one day. Given the speed and low number of flies required, this method enables the use of downstream RT-qPCR and/or RNA sequencing to the study gene expression in the SCs from different genetic backgrounds, ages, mating statuses or environmental conditions.

Here, we describe the dissociation and sorting of a specific cell population from the Drosophila male accessory glands (Secondary cells), followed by RNA extraction for sequencing and RT-qPCR. The dissociation consists of dissection, proteases digestion and mechanical dispersion, followed by FACS purification of GFP-expressing cells.
Enhanced biodegradation of naphthalene byPseudomonassp. consortium immobilized in calcium alginate beads
Authors: Dutta Kunal , Shityakov Sergey , Khalifa Ibrahim , Ballav Saroj , Jana Debarati , Manna Tuhin , Karmakar Monalisha , Raul Priyanka , Guchhait Kartik Chandra , Ghosh Chandradipa
Published: May 2019

Polycyclic aromatic hydrocarbons (PAHs) belong to a large group of organic pollutant which considers as a potential health hazard to living beings. Herein, naphthalene biodegradation potential by free and immobilizedPseudomonas putidastrain KD10 andPseudomonassp. consortium were studied. Additionally, naphthalene 1, 2-dioxygenase (nahAc) was sequenced and analyzed, which reveals two altered amino acid residues. However, the altered amino acid residues are not present in the vicinity of the active site. The gas-phase binding free energy (ΔGLondon) of the mutant variant of naphthalene 1, 2-dioxygenase was -7.10 kcal mol-1which closely resembles the wild type variant. Naphthalene biodegradation rate byPseudomonas putidastrain KD10 was 79.12 mg L-1day-1and it was significantly elevated up to 123 mg L-1day-1by the immobilizedPseudomonassp. consortium. The half-life (t1/2) for naphthalene biodegradation was 3.1 days with the inhibition constant (ki), substrate saturation constant (ks) and maximum specific degradation rate constant (qmax) of 1268 mg L-1, 395.5 mg L-1and 0.65 h-1, respectively, for thePseudomonas putidastrain KD10. However, the t1/2value was significantly reduced to 2 days along withki,ksandqmaxvalues of 1475 mg L-1, 298.8 mg L-1and 0.71 h-1, respectively, by the immobilizedPseudomonassp. consortium. The GC-MS data suggest that KD10 might follow D-gluconic acid mediated meta-cleavage pathway of catechol biodegradation. It is concluded that naphthalene biodegradation performance by immobilizedPseudomonassp. consortium was superior to free or immobilizedPseudomonas putidaKD10. Microbial consortium immobilization could be a useful tool for water quality management and environmental remediation.

Highlights

Superior naphthalene biodegradation byPseudomonassp. consortium immobilized in calcium alginate beads.

A common mutation prone amino acid stretch inside chain A of naphthalene 1, 2-dioxygenase has been identified.

A new naphthalene biodegradation pathway byPseudomonas putidastrain KD10 has been proposed.
A longitudinal study on morphogenetic diversity of pathogenic Rhizoctonia solani from sugar beet and dry beans of western Nebraska
Authors: Das Saurav , Plyler-Harveson Tammy , Santra Dipak K. , Harveson Robert M. , Nielsen Kathy A.
Published: May 2019

Root and stem rot caused by Rhizoctonia solani is a serious fungal disease of sugar beet and dry bean production in Nebraska. Objective was to characterize morpho-genetic diversity of 38 Rhizoctonia solani isolated from sugar beet and dry beans fields in western Nebraska over 10 years. Classical morphological features and ISSR marker was used to study the morphogenetic diversity. Fungal colonies were morphologically diverse in shapes, aerial hyphae formation and colony, sclerotia color. Marker analysis using nineteen polymorphic ISSR marker showed polymorphic bands ranged from 15 - 28 with molecular weight 100bp to 3kb. Polymorphic loci ranged from 43.26 – 92.88%. Nei genetic distance within the population was ranged 0.03 –0.09 and Shannon diversity index varied from 0.24 – 0.28. AMOVA analysis based on ΦPT values showed 87% variation within and 13% among the population with statistical significance. Majority of the isolates from sugar beet showed nearby association within the population. There was significant number of cross crop clustering suggesting their broad pathogenicity. Isolates were grouped into three different clusters in UPGMA based cluster analysis using marker information. Interestingly, there was no specific geographical correlation between the isolates. PCA analysis showed randomized distribution among isolates from same geographical origin. Morphological characteristics showed crop-specific two distinct groups of isolates with few exceptions. While, genetic diversity showed two distinct group of isolates, one crop specific and one with wide pathogenicity. This information may help in molecular pathotyping of the pathogen for better disease management.
Complement- and inflammasome-mediated autoinflammation-paroxysmal nocturnal hemoglobinuria
Authors: Hoechsmann Britta , Murakami Yoshiko , Osato Makiko , Knaus Alexej , Kawamoto Michi , Inoue Norimitsu , Hirata Tetsuya , Murata Shogo , Anliker Markus , Eggerman Thomas , Jaeger Marten , Floettmann Ricarda , Hoellein Alexander , Murase Sho , Ueda Yasutaka , Nishimura Jun-ichi , Kanakura Yuzuru , Kohara Nobuo , Schrezenmeier Hubert , Krawitz Peter M. , Kinoshita Taroh
Published: May 2019

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hematopoietic stem cell disorder characterized by complement-mediated hemolysis and thrombosis, and bone marrow failure. Affected cells harbor somatic mutation in X-linkedPIGAgene, essential for the initial step in glycosylphosphatidylinositol (GPI) biosynthesis. Loss of GPI biosynthesis results in defective cell-surface expression of GPI-anchored complement regulators CD59 and DAF. The affected stem cells generate many abnormal blood cells after clonal expansion, which occurs under bone marrow failure. Here, we report the mechanistic basis of a disease entity, autoinflammation-paroxysmal nocturnal hemoglobinuria (AIF-PNH), caused by germline mutation plus somatic loss ofPIGTon chromosome 20q. A region containing maternally imprinted genes implicated in clonal expansion in 20q-myeloproliferative syndromes was lost together with normalPIGTfrom paternal chromosome 20. Taking these findings together with a lack of bone marrow failure, the mechanisms of clonal expansion in AIF-PNH appear to differ from those in PNH. AIF-PNH is characterized by intravascular hemolysis and recurrent autoinflammation, such as urticaria, arthralgia, fever and aseptic meningitis. Consistent with PIGT’s essential role in synthesized GPI’s attachment to precursor proteins, non-protein-linked free GPIs appeared on the surface of PIGT-defective cells. PIGT-defective THP-1 cells accumulated higher levels of C3 fragments and C5b-9 complexes, and secreted more IL-1β than PIGA-defective cells after activation of the complement alternative pathway. IL-1β secretion was dependent upon C5b-9 complexes, accounting for the effectiveness of the anti-C5 drug eculizumab for both intravascular hemolysis and autoinflammation. These results suggest that free GPIs enhance complement activation and inflammasome-mediated IL-1β secretion.
Operating Characteristics of the Rank-Based Inverse Normal Transformation for Quantitative Trait Analysis in Genome-Wide Association Studies
Authors: McCaw Zachary R. , Lane Jacqueline M. , Saxena Richa , Redline Susan , Lin Xihong
Published: May 2019

Summary

Quantitative traits analyzed in Genome-Wide Association Studies (GWAS) are often non-normally distributed. For such traits, association tests based on standard linear regression are subject to reduced power and inflated type I error in finite samples. Applying the rank-based Inverse Normal Transformation (INT) to non-normally distributed traits has become common practice in GWAS. However, the different variations on INT-based association testing have not been formally defined, and guidance is lacking on when to use which approach. In this paper, we formally define and systematically compare the direct (D-INT) and indirect (I-INT) INT-based association tests. We discuss their assumptions, underlying generative models, and connections. We demonstrate that the relative powers of D-INT and I-INT depend on the underlying data generating process. Since neither approach is uniformly most powerful, we combine them into an adaptive omnibus test (O-INT). O-INT is robust to model misspecification, protects the type I error, and is well powered against a wide range of non-normally distributed traits. Extensive simulations were conducted to examine the finite sample operating characteristics of these tests. Our results demonstrate that, for non-normally distributed traits, INT-based tests outperform the standard untransformed association test (UAT), both in terms of power and type I error rate control. We apply the proposed methods to GWAS of spirometry traits in the UK Biobank. O-INT has been implemented in the R package RNOmni, which is available on CRAN.
Non-Uniformity of Projection Distributions Attenuates Resolution in Cryo-EM
Authors: Baldwin Philip R. , Lyumkis Dmitry
Published: May 2019

Virtually every single-particle cryo-EM experiment currently suffers from specimen adherence to the air-water interface, leading to a non-uniform distribution in the set of projection views. Whereas it is well accepted that uniform projection distributions can lead to high-resolution reconstructions, non-uniform (anisotropic) distributions can negatively affect map quality, elongate structural features, and in some cases, prohibit interpretation altogether. Although some consequences of non-uniform sampling have been described qualitatively, we know little about how sampling quantitatively affects resolution in cryo-EM, especially given the numerous different projection schemes that can arise in experimental situations. Here, we show how inhomogeneity in any projection distribution scheme attenuates the global Fourier Shell Correlation (FSC) in relation to the number of particles and a single geometrical parameter, which we term the sampling compensation factor (SCF). The reciprocal of the SCF is defined as the average over Fourier shells of the reciprocal of the per-particle sampling and normalized to unity for uniform distributions. The SCF therefore ranges from one to zero, with values close to the latter implying large regions of poorly sampled or completely missing data in Fourier space. Using two synthetic test cases, influenza hemagglutinin and human apoferritin, we demonstrate how any amount of sampling inhomogeneity always attenuates the FSC compared to a uniform distribution. We advocate quantitative evaluation of the SCF criterion to approximate the effect of non-uniform sampling on resolution within experimental single-particle cryo-EM reconstructions.
The effect of NMDA-R antagonist, MK-801, on neuronal mismatch along the auditory thalamocortical pathway
Authors: Parras Gloria G , Valdés-Baizabal Catalina , Harms Lauren , Michie Patricia , Malmierca Manuel S
Published: May 2019

Efficient sensory processing requires that the brain is able to maximize its response to unexpected stimuli, while suppressing responsivity to expected events. Mismatch negativity (MMN) is an auditory event-related potential that occurs when a regular pattern is interrupted by an event that violates the expected properties of the pattern. MMN has been found to be reduced in individuals with schizophrenia in over 100 separate studies, an effect believed to be underpinned by glutamate N-methyl-D-aspartate receptor (NMDA-R) dysfunction, as it is observed that NMDA-R antagonists also reduce MMN in healthy volunteers. The aim of the current study is to examine this effect in rodents. Using single unit recording in specific auditory areas using methods not readily utilized in humans, we have previously demonstrated that neuronal indices of rodent mismatch responses recorded from thalamic and cortical areas of the brain can be decomposed into a relatively simple repetition suppression and a more sophisticated prediction error process. In the current study, we aimed to test how the NMDA-R antagonist, MK-801, affected both of these processes along the rat auditory thalamocortical pathway. We found that MK-801 had the opposite effect than expected, and enhanced thalamic repetition suppression and cortical prediction error. These single unit data correlate with the recordings of local field responses. Together with previous data, this study suggests that our understanding of the contribution of NMDA-R system to MMN generation is far from complete, and also has potential implications for future research in schizophrenia.

Significance Statement

In this study, we demonstrate that an NMDA-R antagonist, MK-801, differentially affects single neuron responses to auditory stimuli along the thalamocortical axis by increasing the response magnitude of unexpected events in the auditory cortex and intensifying the adaptation of responses to expected events in the thalamus. Thus, we provide evidence that NMDA-R antagonists alter the balance between prediction-error and repetition suppression processes that underlie the generation of mismatch responses in the brain, and these effects are differentially expressed at different levels of auditory processing. As effects of MK-801 were in the opposite direction to our expectations, it demonstrates that our understanding of role of NMDA-R in synaptic plasticity and the neural processes underpinning MMN generation are far from complete.
Asymmetry in kinematic generalization between visual and passive lead-in movements are consistent with a forward model in the sensorimotor system
Authors: Howard Ian S. , Franklin Sae , Franklin David W.
Published: May 2019

In our daily life we often make complex actions comprised of linked movements, such as reaching for a cup of coffee and bringing it to our mouth to drink. Recent work has highlighted the role of such linked movements in the formation of independent motor memories, affecting the learning rate and ability to learn opposing force fields. In these studies, distinct prior movements (lead-in movements) allow adaptation of opposing dynamics on the following movement. Purely visual or purely passive lead-in movements exhibit different angular generalization functions of this motor memory as the lead-in movements are modified, suggesting different neural representations. However, we currently have no understanding of how different movement kinematics (distance, speed or duration) affect this recall process and the formation of independent motor memories. Here we investigate such kinematic generalization for both passive and visual lead-in movements to probe their individual characteristics. After participants adapted to opposing force fields using training lead-in movements, the lead-in kinematics were modified on random trials to test generalization. For both visual and passive modalities, recalled compensation was sensitive to lead-in duration and peak speed, falling off away from the training condition. However, little reduction in force was found with increasing lead-in distance. Interestingly, asymmetric transfer between lead-in movement modalities was also observed, with partial transfer from passive to visual, but very little vice versa. Overall these tuning effects were stronger for passive compared to visual lead-ins demonstrating the difference in these sensory inputs in regulating motor memories. Our results suggest these effects are a consequence of state estimation, with differences across modalities reflecting their different levels of sensory uncertainty arising as a consequence of dissimilar feedback delays.
Seasonal influenza: Modelling approaches to capture immunity propagation
Authors: Hill Edward M. , Petrou Stavros , de Lusignan Simon , Yonova Ivelina , Keeling Matt J.
Published: May 2019

Seasonal influenza poses serious problems for global public health, being a significant contributor to morbidity and mortality. In England, there has been a long-standing national vaccination programme, with vaccination of at-risk groups and children offering partial protection against infection. Transmission models have been a fundamental component of analysis, informing the efficient use of limited resources. However, these models generally treat each season and each strain circulating within that season in isolation. Here, we amalgamate multiple data sources to calibrate a susceptible-latent-infected-recovered type transmission model for seasonal influenza, incorporating the four main strains and mechanisms linking prior season epidemiological out-comes to immunity at the beginning of the following season. Data pertaining to nine influenza seasons, starting with the 2009/10 season, informed our estimates for epidemiological processes, virological sample positivity, vaccine uptake and efficacy attributes, and general practitioner influenza-like-illness consultations as reported by the Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC). We performed parameter inference via approximate Bayesian computation to assess strain transmissibility, dependence of present season influenza immunity on prior protection, and variability in the influenza case ascertainment across seasons. This produced reasonable agreement between model and data on the annual strain composition. Parameter fits indicated that the propagation of immunity from one season to the next is weaker if vaccine derived, compared to natural immunity from infection. Projecting the dynamics forward in time suggests that while historic immunity plays an important role in determining annual strain composition, the variability in vaccine efficacy hampers our ability to make long-term predictions.
Binding of metal ions and water molecules to nucleic acid bases: the influence of water molecule coordination to a metal ion on water–nucleic acid base hydrogen bonds
Authors: Andrić Jelena M. , Stanković Ivana M. , Zarić Snežana D.
Published: May 2019

The interactions of nucleic acid bases with non-coordinated and coordinated water molecules were studied by analyzing data in the Protein Data Bank (PDB) and by quantum chemical calculations. The analysis of the data in the crystal structures from the PDB indicates that hydrogen bonds involving oxygen or nitrogen atoms of nucleic acid bases and water molecules are shorter when water is bonded to a metal ion. These results are in agreement with the quantum chemical calculations on geometries and interaction energies of hydrogen bonds; the calculations on model systems show that hydrogen bonds of nucleic acid bases with water bonded to a metal ion are stronger than hydrogen bonds with non-coordinated water. These calculated values are similar to the strength of hydrogen bonds between nucleic acid bases. The results presented in this paper may be relevant to understand the role of water molecules and metal ions in the process of replication and stabilization of nucleic acids and also to understand the possible toxicity of metal ion interactions with nucleic acids.
Elucidation of correlated disorder in zeolite IM-18
Authors: Wang Xiaoge , Shen Yihan , Liu Rongli , Liu Xiaolong , Lin Cong , Shi Dier , Chen Yanping , Liao Fuhui , Lin Jianhua , Sun Junliang
Published: May 2019

Classical crystallography is based on the translational periodicity of crystals and the analysis of discrete Bragg reflections. However, it is inadequate for determining disordered structures, of which the diffuse scattering is vital to evaluate the disorder level. The correlated disorder of IM-18 presents as zigzag chains arranged in translational periodicity and the double four-ring units randomly distributed along two dimensions. Supercell models regulated by multiple probabilities were systematically built to simulate the single-crystal and powder X-ray diffraction patterns in order to ascertain the specific disorder configuration in the single-crystal or polycrystalline samples of IM-18. The presence of defects in the polycrystalline sample was proved by combining29Si magic angle spinning (MAS) NMR and1H–1H double quantum MAS NMR spectra, and was quantitatively explored by the simulation method. The method could also elucidate other disordered structures in polycrystalline or single-crystal samples, despite the presence of defects or multidimensional disorder.
Formation of the cementite crystal in austenite by transformation of triangulated polyhedra
Authors: Kraposhin V. S. , Simich-Lafitskiy N. D. , Talis A. L. , Everstov A. A. , Semenov M. Yu.
Published: May 2019

A mechanism is proposed for the nucleus formation at the mutual transformation of austenite and cementite crystals. The mechanism is founded on the interpretation of the considered structures as crystallographic tiling onto non-intersecting rods of triangulated polyhedra. A 15-vertex fragment of this linear substructure of austenite (cementite) can be transformed by diagonal flipping in a rhombus consisting of two adjacent triangular faces into a 15-vertex fragment of cementite (austenite). In the case of the mutual austenite–cementite transformation, the mutual orientation of the initial and final fragments coincides with the Thomson–Howell orientation relationships which are experimentally observed [Thompson & Howell (1988). Scr. Metall.
22, 229–233] in steels. The observed orientation relationship between f.c.c. austenite and cementite is determined by a crystallographic group–subgroup relationship between transformation participants and noncrystallographic symmetry which determines the transformation of triangulated clusters of transformation participants. Sequential fulfillment of diagonal flipping in the 15-vertex fragments of linear substructure (these fragments are equivalent by translation) ensures the austenite–cementite transformation in the whole infinite crystal. The energy barrier for diagonal flipping in the rhombus with iron atoms in its vertices has been calculated using the Morse interatomic potential and is found to be equal to 162 kJ mol−1 at the face-centered cubic–body-centered cubic transformation temperature in iron.
Cruzain structures: apocruzain and cruzain bound to S-methyl thiomethanesulfonate and implications for drug design
Authors: Barbosa da Silva Elany , Dall Elfriede , Briza Peter , Brandstetter Hans , Ferreira Rafaela Salgado
Published: May 2019

Chagas disease, which is caused by Trypanosoma cruzi, affects more than six million people worldwide. Cruzain is the major cysteine protease involved in the survival of this parasite. Here, the expression, purification and crystallization of this enzyme are reported. The cruzain crystals diffracted to 1.2 Å resolution, yielding two novel cruzain structures: apocruzain and cruzain bound to the reversible covalent inhibitor S-methyl thiomethanesulfonate. Mass-spectrometric experiments confirmed the presence of a methylthiol group attached to the catalytic cysteine. Comparison of these structures with previously published structures indicates the rigidity of the cruzain structure. These results provide further structural information about the enzyme and may help in new in silico studies to identify or optimize novel prototypes of cruzain inhibitors.
Structure of the Prx6-subfamily 1-Cys peroxiredoxin from Sulfolobus islandicus
Authors: Stroobants Sander , Van Molle Inge , Saidi Queen , Jonckheere Karl , Maes Dominique , Peeters Eveline
Published: May 2019

Aerobic thermoacidophilic archaea belonging to the genus Sulfolobus harbor peroxiredoxins, thiol-dependent peroxidases that assist in protecting the cells from oxidative damage. Here, the crystal structure of the 1-Cys peroxiredoxin from Sulfolobus islandicus, named 1-Cys SiPrx, is presented. A 2.75 Å resolution data set was collected from a crystal belonging to space group P212121, with unit-cell parameters a = 86.8, b = 159.1, c = 189.3 Å, α = β = γ = 90°. The structure was solved by molecular replacement using the homologous Aeropyrum pernix peroxiredoxin (ApPrx) structure as a search model. In the crystal structure, 1-Cys SiPrx assembles into a ring-shaped decamer composed of five homodimers. This quaternary structure corresponds to the oligomeric state of the protein in solution, as observed by size-exclusion chromatography. 1-Cys SiPrx harbors only a single cysteine, which is the peroxidatic cysteine, and lacks both of the cysteines that are highly conserved in the C-terminal arm domain in other archaeal Prx6-subfamily proteins such as ApPrx and that are involved in the association of dimers into higher-molecular-weight decamers and dodecamers. It is thus concluded that the Sulfolobus Prx6-subfamily protein undergoes decamerization independently of arm-domain cysteines.
Antecedents of entrepreneurial intentions amongst business students in a tertiary institution
Authors: Agolla Joseph Evans , Monametsi Gladness L. , Phera Petty
Published: May 2019

Purpose

The purpose of this paper is to examine the antecedents of entrepreneurial intentions amongst open and distance learning students during employment crisis. To achieve the purpose of this study, Ajzen’s theory of planned behaviour (TPB) was applied and empirically tested on the sample population.

Design/methodology/approach

Data were taken from a sample of university students pursuing business-related courses in Open and Distance Learning mode. Self-reported questionnaires were handed to a total of 500 students to complete and return. Returned and usable questionnaires numbered 245 in total, giving a return rate of 49 per cent. Descriptive statistics and regression analyses were utilised to analyse data. Structural equation modelling incorporated into SPSS was used to assess the structural model.

Findings

The key finding reveal that Ajzen’s TPB can partially be applied in determining entrepreneurial intentions in the developing economy. The study results also revealed that perceived behavioural control, personal attitude and subjective norm (SN) explained 62.5 per cent of variations in entrepreneurial intention, which surpasses many other studies conducted previously.

Research limitations/implications

Present study relied on cross-sectional data using quantitative design, therefore limiting the full understanding of the causal relationship between variables.

Originality/value

The study developed a conceptual framework based on literature that was empirically tested, which adds to existing ones, thereby extending the literature in the field. Moreover, the study managed to incorporate SN as an intervening variable, which has rarely been done.
The fluidity of risk
Authors: Lewis James
Published: May 2019

Purpose

Considered alone, risk is static; the purpose of this paper is to illustrate risk not as static but as a fluid condition dependent, for example, upon circumstances of its context in changeable vulnerability and behavioural responses of people facing risk.

Design/methodology/approach

Psychology provides strong evidence of behavioural response when facing hazards; technological disasters providing more evidence of behavioural responses to hazards and risk than response to disasters assumed to be “natural”. Initial and subsequent behavioural responses may critically affect ultimate outcomes. Post-event inquiries into technological disasters have revealed actions and inactions which created or aggravated subsequent consequences and their aftermath.

Findings

Decisions taken at a Japanese school between the 2011 earthquake and tsunami, and details of the 2017 fire at a tower-block in London, UK, indicate, in spite of training, that rigidity, uncertainty, hesitation or waver may affect critical decisions and their consequences. Pre- and post-disaster behaviour may not follow preferred patterns. Fear of imagined or real events may induce unanticipated denial of the reality of risk. Physical changes made after assessments of risk may not be recognised as affecting risk.

Research limitations/implications

Few published examples exist of public inquiries following disasters assumed to be from natural causes.

Practical implications

Reports of inquiries into technological disasters provide significant examples of behavioural responses which, if replicated, may influence outcomes of disasters labelled as “natural”.

Social implications

Awareness of risk as a fluid condition will facilitate realisation of effects upon risk of uncompleted or ongoing works, inappropriate behavioural responses, undeveloped resilience and of the need for regular reassessments of risk.

Originality/value

This study encourages comprehension of risk as an evolving and fluid condition.
A spatial and integrated flood risk diagnosis
Authors: Bennani Oumaima , Druon Ernest , Leone Frédéric , Tramblay Yves , Saidi Mohamed El Mehdi
Published: May 2019

Purpose

The purpose of this paper is to identify vulnerable areas for flood hazard and to analyze stakes exposed in touristic valley of Morrocan mountains. The three goals are: methodological (low-cost diagnosis without starting data), operational (to show the risk and identify avenues of prevention in Ourika) and incentive (to reproduce this on other sectors in Morocco).

Design/methodology/approach

The vulnerability of three areas of the Ourika valley (the most frequented) was assessed by a hydro-geomorphological study, human frequentation surveys and risk indices at the building scale.

Findings

Surveys carried out in the field allowed the identification of areas with high risk, the evaluation of the buildings’ vulnerability and the frequentation of the valley. Evacuation plans, allowing easy access to potential refuges in case of flood, were finally proposed.

Originality/value

The reproducible, inexpensive and relevant nature of the approach (integrated and spatialized) helps in decision making and facilitating dialogue for prevention.
The direction of the response scale matters – accounting for the unit of measurement
Authors: Salzberger Thomas , Koller Monika
Published: May 2019

Purpose

Psychometric analyses of self-administered questionnaire data tend to focus on items and instruments as a whole. The purpose of this paper is to investigate the functioning of the response scale and its impact on measurement precision. In terms of the response scale direction, existing evidence is mixed and inconclusive.

Design/methodology/approach

Three experiments are conducted to examine the functioning of response scales of different direction, ranging from agree to disagree versus from disagree to agree. The response scale direction effect is exemplified by two different latent constructs by applying the Rasch model for measurement.

Findings

The agree-to-disagree format generally performs better than the disagree-to-agree variant with spatial proximity between the statement and the agree-pole of the scale appearing to drive the effect. The difference is essentially related to the unit of measurement.

Research limitations/implications

A careful investigation of the functioning of the response scale should be part of every psychometric assessment. The framework of Rasch measurement theory offers unique opportunities in this regard.

Practical implications

Besides content, validity and reliability, academics and practitioners utilising published measurement instruments are advised to consider any evidence on the response scale functioning that is available.

Originality/value

The study exemplifies the application of the Rasch model to assess measurement precision as a function of the design of the response scale. The methodology raises the awareness for the unit of measurement, which typically remains hidden.
Shifting preservice teachers’ beliefs: toward critical connected learning
Authors: Struck Maggie , Rollag Yoon Stephanie
Published: May 2019

Purpose

The purpose of this paper is to explore how preservice teacher’s beliefs change over time in a literacy methods elementary licensure course that encourages critical literacy and connects learning. The authors were interested in the interplay among identity, agency and structure within this process and how this connected with other literature on teacher beliefs and technology use.

Design/methodology/approach

Utilizing data from a larger ethnographic study and mediated discourse analysis (Scollon and Scollon, 2004), this paper follows preservice teacher’s use of digital tools and beliefs about using digital tools in the classroom over a semester-long hybrid course.

Findings

Findings show changes in preservice teacher’s beliefs about technology use, interest-driven learning and her own agency. These changes were influenced by the framework of the course and course practices.

Research limitations/implications

This research study offers practical ways to support preservice teachers’ implementation of digital tools with an emphasis on equity. Ultimately, preservice teachers’ experience shapes the opportunities students have with digital tools in schools.

Practical implications

Recognizing the competing discourses and pressures preservice teachers’ experience, the results of this study offer tools to support preservice teachers’ agency through the implementation of connected learning principles and critical literacy theories in preservice education courses, leading to the potential to expand equity in school settings.

Originality/value

While there is research around connected learning in classrooms, there is limited research on a connected learning framework in preservice education programs. Additionally, this paper brings a new perspective on how pairing an emphasis of equity to a connected learning framework supports teachers’ implementation of digital tools.
Intra-organizational communication, understanding, and process diffusion in logistics service providers
Authors: Grawe Scott J. , Ralston Peter M.
Published: May 2019

Purpose

The purpose of this paper is to investigate, using survey data, how a firm may be able to leverage innovation or processes specifically developed for one customer across its entire customer network using on-site, or implanted, employees.

Design/methodology/approach

Data collected from a survey of 309 implanted logistics service provider (LSP) representatives are analyzed using structural equation modeling.

Findings

The findings show that intra-organizational task interdependence and face-to-face communication can lead to a greater understanding of firm processes developed for specific customers and greater diffusion of these new processes to other customers. Rather than separating customers that require implanted employees, these implants can be a conduit of valuable information and process enhancements that can positively impact a firm’s customer network.

Originality/value

The current research shows how LSPs can effectively use their customer networks to provide process improvements for multiple customers. Specifically, transferring processes between customers can lead to efficiencies and contribute to supply chain robustness not possible without process diffusion.
The influence of peer assessment training on assessment knowledge and reflective writing skill
Authors: Hoffman Bobby
Published: May 2019

Purpose

The purpose of this paper is to examine the influence of peer-assessment training as a catalyst to enhance student assessment knowledge and the ability to effectively evaluate reflective journal writing assignments when using the online peer assessment (PA) tool Expertiza.

Design/methodology/approach

Over a two-year period, end-of-unit assessment test scores and reflective writing samples from a peer-assessment participation group were compared to a no peer-assessment control group. Analysis of covariance was used to control for existing writing skill and ongoing feedback on writing samples.

Findings

No significant increases were observed in student assessment knowledge when participating in peer-assessment training. Comparison of matched participant samples revealed that after controlling for existing writing skill, students participating in PA graded reflective writing assignments significantly lower than instructor-graded assessments from students not afforded peer-assessment participation.

Research limitations/implications

No distinction was made on the relative influence of giving or receiving PA influenced performance on the outcome measures. Second, students making multiple revisions based on feedback were not analyzed. Third, the Expertiza system does not control for the number of reviews performed, thus differential weighting of assessment outcomes may be realized unless all students submit and perform the same number of assessments. Finally, in absence of any qualitative analysis as to what factors students consider when grading writing samples, it is unknown as to how individual difference factors or adherence to scoring rubrics may have influenced the obtained results.

Practical implications

Students may be reticent evaluating peers or utilize grading criteria beyond the mandatory evaluation rubrics. Clear distinctions should be provided to students indicating how instructional content aligns with skills needed to conduct assessment. Training that addresses the theoretical and transactional components of PA are important, but teachers should recognize that when developing assessment skills learners undergo a developmental catharsis related to building trust and establishing a secure and comfortable identity as an assessor. Peer review systems should quantify the relative contribution of each reviewer through the measurement of frequency, timeliness and accuracy of the feedback, compared with instructor standards/evaluations.

Originality/value

This paper reduces the gap in the literature concerning how PA evolves over time and identifies factors related to the etiology of the peer-review process. In addition, the paper reveals new information regarding the calibration between instructor and peer evaluations.
Active and wealthy Brazilian older adults: identity and consumption motivations
Authors: Fregolente Andre , Junqueira Irene , Medeiros Priscilla Yung
Published: May 2019

Purpose

This paper aims to explore the relationship between identity construction and consumption motivation of the socially active and wealthy Brazilian older adults, applying a new approach that focuses on important circumstances and life events retrieved through storytelling.

Design/methodology/approach

Using in-depth semi-structured interviews with socially active and wealthy older Brazilian consumers, this study adopts “Noting, Collecting and Thinking about Things” (NCT) and two-cycle coding methods to explore the qualitative data.

Findings

The results indicate the need to explore identity construction and consumption motivation in an integrated matter. Life circumstances and events help explain older consumers’ identities and its impact on main consumption motivations, which include self-expression, a need for social contact and relationships, attachment, detachment, nostalgia, knowledge appreciation and technology affinity, among others. An integrated approach allows for the identification of new consumption motivations.

Practical implications

The main consumption motivations identified in this study help delineate some new marketing strategies targeted to older consumers, such as taking into account the importance of building relationships with older customers, adopting family references to promote products and services, taking into account the value older customers place on technology usage and being connected with current matters and treating the elderly as a heterogeneous group, among others.

Originality/value

This paper focuses on an attractive and yet unexplored segment of older consumers in the literature, contextualizing their identity and consumption motivations in an integrated fashion, rather than studying these concepts in isolation. New marketing strategies targeted to the older consumers are identified.
A dual-pathway model of knowledge exchange: linking human and psychosocial capital with prosocial knowledge effectiveness
Authors: Singh Sanjay Kumar , Mittal Shashank , Sengupta Atri , Pradhan Rabindra Kumar
Published: May 2019

Purpose

This study aims to examine a dual-pathway model that recognizes two distinct (formal and informal) but complementary mechanisms of knowledge exchanges – knowledge sharing and knowledge helping. It also investigates how team members use their limited human and psychosocial capital for prosocial knowledge effectiveness.

Design/methodology/approach

A survey-based approach was used to examine the hypotheses of the study. A moderated-mediation model was proposed and tested using bootstrap approach.

Findings

Knowledge sharing and knowledge helping were found to be the significant links through which human capital (capability) and psychosocial capital (motivation and efficacy) significantly predict prosocial knowledge effectiveness. Post hoc analysis suggests that human capital through knowledge sharing influences team learning, whereas the psychosocial capital through knowledge helping influences team leadership.

Originality/value

The present study found two distinct but complementary and yet necessary mechanisms of knowledge exchanges to be linked as the important outlay for the human and psychosocial capital to be effective in the prosocial knowledge behaviours.
Effectiveness of training, based on positive psychology and social skills, applied to supervisors, to face resistance to organizational change
Authors: Veloso-Besio Constanza Beatriz , Cuadra-Peralta Alejandro , Gil-Rodríguez Francisco , Ponce-Correa Felipe , Sjöberg-Tapia Oscar
Published: May 2019

Purpose

The purpose of this paper is to analyze the effectiveness of training, applied to supervisors, to face the effects of resistance to organizational change on work motivation and organizational climate of their direct employees.

Design/methodology/approach

A quasi-experimental design with a control group was used. The training program was applied in a public organization, which was going through a process of organizational change. The human resources unit formed two groups according to the needs of the organization. A group of seven supervisors received training (experimental group), and another group of eight supervisors received no training (control group). The effectiveness of the training was measured in the subalterns of the supervisors who formed both groups. The training was based on positive psychology and social skills and covered a period of one month and three weeks. The outcomes variables were: work motivation and organizational climate.

Findings

There was a statistically significant increase, from the pretest to the posttest, in the dependent variables registered in the experimental group, compared to the control group. The size of the change (effect size) was moderate magnitude to high.

Originality/value

This research shows an effective training system, applied in supervisors, to improve the work motivation and the organizational climate of the subordinates in processes of organizational change that generate resistance to change in them.