bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Modeling of γ-Secretase Aβn Complex Formation and Substrate Processing
Authors: Hitzenberger M. , Zacharias M.
Published: December 2018

The intra-membrane aspartyl protease γ-secretase (GSEC) cleaves single-span transmembrane helices including the C-terminal fragment of the amyloid precursor protein (APP). This substrate is initially cleaved at the ɛ-site followed by successive processing (trimming) events mostly in steps of three amino acids. GSEC is responsible for the formation of N-terminal APP amyloid-β (A β) peptides of different length (e.g. Aβ42) that can form aggregates involved in Alzheimer’s disease pathogenesis. The molecular mechanism of GSEC-APP substrate recognition is key for understanding how different peptide products are formed and could help in designing APP-selective modulators. Based on the known structure of apo GSEC and the APP-C99 fragment we have generated putative structural models of the initial binding in three different possible modes using extensive Molecular Dynamics (MD) simulations. The binding mode with the substrate helix located in a cleft between the transmembrane helices 2 and 3 of the presenilin subunit was identified as a most likely binding mode. Based on this arrangement the processing steps were investigated using restraint MD simulations to pull the scissile bond (for each processing step) into a transition like (cleavable) state. This allowed us to analyze in detail the motions and energetic contributions of participating residues. The structural model agrees qualitatively well with the influence of many mutations in GSEC and C99. It also explains the effects of inhibitors, cross-linking as well as spectroscopic data on GSEC substrate binding and can serve as working model for the future planning of structural and biochemical studies.
Moments reconstruction and local dynamic range compression of high order Superresolution Optical Fluctuation Imaging
Authors: Yi Xiyu , Son Sungho , Ando Ryoko , Miyawaki Atsushi , Weiss Shimon
Published: December 2018

Super-resolution Optical Fluctuation Imaging (SOFI) offers a simple and affordable alternative to other super-resolution (SR) imaging techniques. The theoretical resolution enhancement of SOFI scales linearly with the cumulants’ order, while imaging conditions are less phototoxic to living samples as compared to other SR methods. High order SOFI could, therefore, be a method of choice for dynamic live cell imaging. However, due to cusp-artifacts and to dynamic range expansion of pixel intensities, this promise has not been materialized as of yet. Here we investigated and compared high order moments vs. high order cumulants SOFI reconstructions. We demonstrate that even-order moments reconstructions are intrinsically free of cusp artifacts, allowing for a subsequent deconvolution operation to be performed, hence enhancing the resolution even further. High order moments reconstructions performance was examined for various (simulated) conditions and applied to (experimental) imaging of QD labeled microtubules in fixed cells, and actin stress fiber dynamics in live cells.
Assembly of functionally antagonistic visual circuits for controlling pupil dynamics
Authors: Dhande Onkar S , Seabrook Tania A , Phan Ann H , Salaly Lindsey D , Ishiko Nao , Nguyen Phong L , Wang Jack T , Evans Sylvia M , Huberman Andrew D
Published: December 2018

The functional attributes of parallel sensory circuits are determined by the properties of the individual cell types that comprise them, and their connectivity. The mechanisms controlling the specification and establishment of parallel sensory pathways remain unclear. Here we report the non-uniform distribution of retinal ganglion cells (RGCs) expressing the transcription factor Tbx20 in mice. Owing to their layout within the retina, Tbx20-RGCs are positioned to preferentially encode light information from dorsal visual space. We discovered that Tbx20 expression is mostly restricted to three RGC-types: M1 intrinsically photosensitive RGCs (ipRGCs), M2 ipRGCs and 'diving' RGCs. The axonal projections of Tbx20-RGCs innervate non-image-forming brain centers including the suprachiasmatic nucleus, the medial division of the posterior pretectal nucleus, and the olivary pretectal nucleus (OPN), a principal station in the neural pathway for generating the pupillary light reflex (PLR). Conditional deletion of Tbx20 resulted in reduced Tbx20-RGC axonal innervation of these targets and revealed a key role of these neurons in driving specific phases of the PLR. Furthermore, chemogenetic activation uncovered a novel role for a specific subset of Tbx20-RGCs in controlling pupil dilation. These data offer a new understanding of the genetic and molecular mechanisms that establish specific, behaviorally-relevant visual circuits.
Decreased metabolism and increased tolerability to extreme environment in Staphylococcus warneri with long-term space flight
Authors: Bai Po , Zhang Bin , Zhao Xian , Li Diangeng , Yu Yi , Zhang Xuelin , Huang Bing , Liu Changting
Published: December 2018

Background:Many studies have shown that space environment can affect bacteria to cause a range of mutations. However, so far, there are less studies on the effects of long-term space flight (>1 month) on bacteria. In this study, a Staphylococcus warneri strain, which was isolated from the Shenzhou-10 spacecraft that had experienced a space flight (15-day), was carried into space again. After 64-day flight, the combined phenotypic, genomic, transcriptomic and proteomic analyses were performed to compare the influence of the two space flights on this bacteria. Results: Compared with short-term space flight, long-term space flight increased the biofilm formation ability of S. warneri and the cell wall resistance to external environment stress, but reduced the sensitivity to chemical stimulation. Further analysis showed that these changes might be related to the significantly up-regulated gene expression of phosphotransferase system, which regulated glucose metabolism pathway, including glucose, mannose, fructose and cellobiose. The mutation of S. warneri caused by 15-day space flight was limited at phenotype and gene level after ground culture. Conclusion: After a 79-day space flight, the changes of S. warneri are meaningful. Phosphotransferase system of S. warneri was up-regulated by long-term space stimulation, which resulted in a series of changes in cell wall, biofilm and chemical sensitivity, thus enhancing the resistance and adaptability of bacteria to the external environment.
Oxytocin facilitates self-serving rather than altruistic tendencies in competitive social interactions via orbitofrontal cortex
Authors: Xu Xiaolei , Liu Congcong , Zhou Xinqi , Chen Yuanshu , Gao Zhao , Zhou Feng , Kou Juan , Becker Benjamin , Kendrick Keith
Published: December 2018

While the neuropeptide oxytocin can facilitate empathy and altruistic behavior it may also promote self-serving tendencies in some contexts, and it remains unclear if it would increase altruistic or self-interest behaviors when they compete within a social situation. The current between-subject, double-blind, placebo-controlled fMRI study investigated the effect of intranasal oxytocin on empathy for social exclusion using a modified online ball-tossing game which incorporated monetary rewards and both the potential to display altruistic and self-interest behaviors. Results showed that when subjects in both oxytocin and placebo groups were observing a player being excluded (victim) by other players in the game there was activation in the mentalizing network. When subjects then played both with the victim and the players who had excluded them they threw more balls to the victim player, indicative of an altruistic response. However, subjects in the oxytocin group threw more balls to the excluder players indicative of greater self-interest, since the latter would be perceived as more likely to reciprocate to maximize financial gain. This behavioral effect of oxytocin was associated with greater medial orbitofrontal cortex activation when playing with the excluders and negatively correlated with trait-altruism scores. Overall, our findings suggest that in the context of competing motivations for exhibiting altruistic or self-interest behavior oxytocin enhanced self-interest and this was associated with greater activation in frontal reward areas.
Small RNA bidirectional crosstalk during the interaction between wheat andZymoseptoria tritici
Authors: Ma Xin , Bologna Nicolas , Palma-Guerrero Javier
Published: December 2018

Cross-kingdom RNAi has been shown to play important roles during plant pathogen interactions. But this cross-kingdom RNAi was still unexplored in the wheat-Zymoseptoria triticipathosystem. Here we performed a detailed analysis of the sRNA bidirectional crosstalk between wheat andZ.tritici. Using a combination of sRNA-seq and mRNA-seq we were able to identify known and novel sRNAs and study their expression and their action on putative targets in both wheat andZ.tritici. We predicted the target genes of all the sRNAs in either wheat orZ.triticitranscriptome and used degradome analysis to validate the cleavage of these gene transcripts. We could not find any clear evidence of a cross-kingdom RNAi in this pathosystem. We also found that the fungal sRNA enrichment was lowerin plantathan duringin vitrogrowth, probably due to the lower expression of the only Dicer gene of the fungus during plant infection. However, we found a downregulation of specific wheat sRNAs during the fungal infection, leading to a boost expression of wheat defense related genes, which may be enhancing the plant defense ability against the pathogen. Additionally, the fungal infection also induced sRNAs regulating the expression of specific wheat genes, including auxin related genes, as an immune response. These results confirm the role of sRNAs in the regulation of wheat defenses duringZ.triticiinfection. Our findings contribute to improve our understanding of the interactions between wheat andZ.tritici.
The impact of learning on perceptual decisions and its implication for speed-accuracy tradeoffs
Authors: Mendonça André G. , Drugowitsch Jan , Inês Vicente M. , DeWitt Eric , Pouget Alexandre , Mainen Zachary F.
Published: December 2018

In standard models of perceptual decision-making, noisy sensory evidence is considered to be the primary source of choice errors and the accumulation of evidence needed to overcome this noise gives rise to speed-accuracy tradeoffs. Here, we investigated how the history of recent choices and their outcomes interacts with these processes using a combination of theory and experiment. We found that the speed and accuracy of performance of rats on olfactory decision tasks could be best explained by a Bayesian model that combines reinforcement-based learning with accumulation of uncertain sensory evidence. This model predicted the specific pattern of trial history effects that were found in the data. The results suggest that learning is a critical factor contributing to speed-accuracy tradeoffs in decision-making and that task history effects are not simply biases but rather the signatures of an optimal learning strategy.
Profiling gene expression of the host response to a Plasmodium vivax irradiated sporozoite immunization and infectious challenge
Authors: Rojas-Pena Monica C , Arafat Dalia C , Velasquez Juan Manuel , Garimalla Swetha C , Arevalo-Herrera Myriam , Herrera Socrates , Gibson Greg
Published: December 2018

The development of vaccines that provide sterile protection against human malaria is a major global public health priority requiring a better understanding of the mechanisms involved in natural and vaccine-induced sterile immunity. RNAseq was used to profile gene expression of peripheral blood samples from 12 Duffy positive (Fy+) (Plasmodium vivax susceptible) volunteers enrolled in a phase 2 trial who were vaccinated with radiation attenuated P. vivax sporozoites (RAS; 5 were protected, 7 not) and from 5 Fy- (P. vivax resistant) volunteers exposed to mosquitoes harboring live non-attenuated sporozoites. Blood samples were obtained before and after immunization as well as after controlled infection with live P vivax sporozoites. The most profound changes in gene expression were observed between baseline and post-challenge, with 97 distinct signatures differentiating protected and not protected Fy+ individuals. Differentiation was also observed between Fy- and Fy+ protected individuals, notably with downregulation of multiple inflammatory responses as well as extracellular matrix-related gene activity. Analysis of transcriptional modules shows that both B-cell and T-cell signaling are reduced while cell cycle regulation, interferon response, and other informative signatures are elevated in individuals who are not protected against malaria. An asymptomatic individual had an intermediate profile indicative of differential transcription associated with pathology and symptomology. Systems biology thus provides insight into how whole malaria-attenuated sporozoites prime the immune system to protect against malaria, as well as the transcription responses that are associated with sterile protection.
Motion-in-depth perception and prey capture in the praying mantis
Authors: Nityananda Vivek , Joubier Coline , Tan Jerry , Tarawneh Ghaith , Read Jenny C A
Published: December 2018

Perceiving motion-in-depth is essential to detecting approaching or receding objects, predators and prey. This can be achieved using several cues, including binocular stereoscopic cues such as changing disparity and interocular velocity differences and monocular cues such as looming. While these have been studied in detail in humans, only looming responses have been well characterized in insects and we know nothing about the role that stereo cues play and how they might interact with looming cues. We used our 3D insect cinema in a series of experiments to investigate the role of the stereo cues mentioned above, as well as looming, in the perception of motion-in-depth during predatory strikes by the praying mantis. Our results show that motion-in-depth does increase the probability of mantis strikes but only for the classic looming stimulus, an expanding luminance edge. Approach indicated by radial motion of a texture or expansion of a motion-defined edge, or by stereoscopic cues, all failed to elicit increased striking. We conclude that mantises use stereopsis to detect depth but not motion-in-depth, which is detected via looming.
Ab initiophasing of the diffraction of crystals with translational disorder
Authors: Morgan Andrew J. , Ayyer Kartik , Barty Anton , Chen Joe P. J. , Ekeberg Tomas , Oberthuer Dominik , White Thomas A. , Yefanov Oleksandr , Chapman Henry N.
Published: December 2018

To date X-ray protein crystallography is the most successful technique available for the determination of high-resolution 3D structures of biological molecules and their complexes. In X-ray protein crystallography the structure of a protein is refined against the set of observed Bragg reflections from a protein crystal. The resolution of the refined protein structure is limited by the highest angle at which Bragg reflections can be observed. In addition, the Bragg reflections alone are typically insufficient (by a factor of two) to determine the structureab initio, and so prior information is required. Crystals formed from an imperfect packing of the protein molecules may also exhibit continuous diffraction between and beyond these Bragg reflections. When this is due to random displacements of the molecules from each crystal lattice site, the continuous diffraction provides the necessary information to determine the protein structure without prior knowledge, to a resolution that is not limited by the angular extent of the observed Bragg reflections but instead by that of the diffraction as a whole. This article presents an iterative projection algorithm that simultaneously uses the continuous diffraction as well as the Bragg reflections for the determination of protein structures. The viability of this method is demonstrated on simulated crystal diffraction.
Updating direct methods
Authors: Giacovazzo Carmelo
Published: December 2018

The standard method of joint probability distribution functions, so crucial for the development of direct methods, has been revisited and updated. It consists of three steps: identification of the reflections which may contribute to the estimation of a given structure invariant or seminvariant, calculation of the corresponding joint probability distribution, and derivation of the conditional distribution of the invariant or seminvariant phase given the values of some diffracted amplitudes. In this article the conditional distributions are derived directly without passing through the second step. A good feature of direct methods is that they may work in the absence of any prior information: that is also their weakness. Different types of prior information have been taken into consideration: interatomic distances, interatomic vectors, Patterson peaks, structural model. The method of directly deriving the conditional distributions has been applied to those cases. Some new formulas have been obtained estimating two-, three- and four-phase invariants. Special attention has been dedicated to the practical aspects of the new formulas, in order to simplify their possible use in direct phasing procedures.
Benchmarking supplier external risk factors in electronic equipment industry supply chains
Authors: Lockamy III Archie
Published: December 2018

Purpose

The global electronic equipment industry has evolved into one of the most innovative technology-based business sectors to transpire in the last three decades. Much of its success has been attributed to effective supply chain management. The purpose of this paper is to provide an examination of external risk factors associated with the industry’s key suppliers through the creation of Bayesian networks which can be used to benchmark external risks among these suppliers.

Design/methodology/approach

The study sample consists of the suppliers to seven of the leading global electronic equipment companies. Bayesian networks are used as a methodology for examining the supplier external risk profiles of the study sample.

Findings

The results of this study show that Bayesian networks can be effectively used to assist managers in making decisions regarding current and prospective suppliers with respect to their potential impact on supply chains as illustrated through their corresponding external risk profiles.

Research limitations/implications

A limitation to the use of Bayesian networks for modeling external risk profiles is the proper identification of risk events and risk categories that can impact a supply chain.

Practical implications

The methodology used in this study can be adopted by managers to assist them in making decisions regarding current or prospective suppliers vis-à-vis their corresponding external risk profiles.

Originality/value

As part of a comprehensive supplier risk management program, companies along with their suppliers can develop specific strategies and tactics to minimize the effects of supply chain external risk events.
Digital preservation practices in university libraries
Authors: Anyaoku Ebele N. , Echedom Anthonia U. Nwabueze , Baro Ebikabowei Emmanuel
Published: December 2018

Purpose

The purpose of the study is to investigate the digital preservation practices in institutional repositories (IRs) in Africa.

Design/methodology/approach

Data were collected from the IRs developed in university libraries in Africa, and it was done in two phases. The phases are website investigation to identify the university libraries in Africa that have developed IR and online questionnaire.

Findings

Results from the study showed that the majority of IRs in Africa used DSpace software to manage their digital contents, and more than half of the IRs engage in information migration. The study also revealed that the majority of the responding institutions provide long-term digital preservation in their IR. Interestingly, the majority of the IRs has developed digital preservation policy to guide the implementation of digital preservation for IR contents. Finally, the majority of the respondents indicated that they do not have long-term funding and lack the necessary technical staff with required skills to handle and manage the IR.

Research limitations/implications

Because of language barriers, data were collected from only universities in English speaking countries in Africa.

Practical implications

The findings of this study will make librarians in universities in Africa and other developing countries understand the key issues relating to digital preservation and longevity.

Originality/value

The findings of this study will inform information professionals, librarians in developing countries that are planning to create IRs and provide long-term digital preservation of electronic resources in their institution.
Exaptation in management: beyond technological innovations
Authors: De Sordi José Osvaldo , Nelson Reed Elliot , Meireles Manuel , Hashimoto Marcos , Rigato Carlos
Published: December 2018

Purpose

Although exaptation is recognized as a means of creation capable of generating significant economic implications for organizations, this mechanism has not been explored in depth in the field of management, where it remains restricted to innovation and product research and development. With this limitation in mind, this study aims to explore and discuss exaptation along with other entities that are more greatly concerned with the interests of and direct contact with practitioners and academics in the field of management, such as processes, data, tacit knowledge and skills.

Design/methodology/approach

For the purposes of this study, a comprehensive review of the literature on exaptation was conducted, and 46 entrepreneurs from companies of different sizes and segments were interviewed.

Findings

The results of the review of the literature and interviews with entrepreneurs helped to identify and describe 13 cases of exaptation associated with nine different kinds of organizational entities. For four of these entities, which are closely associated with management, the restrictions of the business environment regarding the exaptation of these entities are discussed, together with the more favorable organizational structures for their occurrence.

Practical implications

This paper discusses the exaptation to the four types of entity closely linked with management: tacit knowledge, data, process and skill. For each one of these entities the following is discussed: the organizational characteristics that hinder the exaptation of the entity in question and the managerial actions that could alter these characteristics and facilitate the occurrence of the exaptation mechanism with the entity in question.

Originality/value

This process led to the development of an algorithm for analyzing the exaptation mechanism and the adaptation of the attributes associated with the agent-artifact[entity]-context tripartite to describe and analyze exaptation event, including another attribute: the type of entity.
Dynamic capabilities
Authors: Sunder M. Vijaya , L.S. Ganesh , Marathe Rahul R.
Published: December 2018

Purpose

The growth, diversity and applications of research into dynamic capabilities (DCs) have resulted in the whole literature on DCs becoming a complex and disconnected body of knowledge. This has led to criticisms of the subject of DCs as being vague, tautological and without practical value. Hence, the purpose of this paper is to synthesize the diverse scholarly literature about DCs and develop a more integrated understanding to minimize the reported apparent vagueness.

Design/methodology/approach

In this paper, the authors review various relevant themes on DCs using a selection of 133 articles published in 22 recognized, top-tier management journals during the period between 1990 and 2016, with an aim to build a structured and integrated theory. For this, morphological analysis (MA), a systems-thinking technique, is applied.

Findings

MA is applied to develop a multi-dimensional conceptual framework comprising five dimensions and 26 variants that enable a structured representation of the conceptual foundations of DCs. Further, the authors identify 81 individual DCs noted by various scholars; elucidate assumptions and antecedents relevant to the DCs approach; structure the key characteristics; and expound the input factors, impacting factors, desired outcomes and assessment yardsticks.

Research limitations/implications

This would be a useful resource for researchers working in the area of DCs to explore opportunities for future research.

Practical implications

The MA framework helps managers to look at DCs more holistically, and hence would help them in developing, managing and retaining DCs in organizations.

Originality/value

This study is the original work contributed by the authors and has no specific organizational reference. This research implies new directions to look beyond individual DCs in firms toward a more integrated theory building.
When to use and how to report the results of PLS-SEM
Authors: Hair Joseph F. , Risher Jeffrey J. , Sarstedt Marko , Ringle Christian M.
Published: December 2018

Purpose

The purpose of this paper is to provide a comprehensive, yet concise, overview of the considerations and metrics required for partial least squares structural equation modeling (PLS-SEM) analysis and result reporting. Preliminary considerations are summarized first, including reasons for choosing PLS-SEM, recommended sample size in selected contexts, distributional assumptions, use of secondary data, statistical power and the need for goodness-of-fit testing. Next, the metrics as well as the rules of thumb that should be applied to assess the PLS-SEM results are covered. Besides presenting established PLS-SEM evaluation criteria, the overview includes the following new guidelines: PLSpredict (i.e., a novel approach for assessing a model’s out-of-sample prediction), metrics for model comparisons, and several complementary methods for checking the results’ robustness.

Design/methodology/approach

This paper provides an overview of previously and recently proposed metrics as well as rules of thumb for evaluating the research results based on the application of PLS-SEM.

Findings

Most of the previously applied metrics for evaluating PLS-SEM results are still relevant. Nevertheless, scholars need to be knowledgeable about recently proposed metrics (e.g. model comparison criteria) and methods (e.g. endogeneity assessment, latent class analysis and PLSpredict), and when and how to apply them to extend their analyses.

Research limitations/implications

Methodological developments associated with PLS-SEM are rapidly emerging. The metrics reported in this paper are useful for current applications, but must always be up to date with the latest developments in the PLS-SEM method.

Originality/value

In light of more recent research and methodological developments in the PLS-SEM domain, guidelines for the method’s use need to be continuously extended and updated. This paper is the most current and comprehensive summary of the PLS-SEM method and the metrics applied to assess its solutions.
Vibration simulation for a cantilever beam including a slant vertical crack
Authors: Song Xiaohua , Shao Yiming
Published: December 2018

Purpose

Modelling methods can be helpful for understanding vibrations of beam structures including cracks, as well as for early detection of crack. This study aims to provide an analytical modelling approach for a cantilever beam considering a slant vertical crack along its height. However, previous uniform crack methods cannot be used for describing this case. The results from the analytical, finite element (FE) and experimental methods are compared to verify the vibration problem.

Design/methodology/approach

A massless rotational spring model is adopted to describe the crack. An extended method based on the calculation method for a uniform vertical edge crack is proposed to obtain the stiffness of the slant case. The beam is divided into a series of independent thin slices along the beam height. An Euler–Bernoulli beam model is applied to formulate each slice. The crack in each slice is considered as a uniform one. The transfer matrix method in the literature is used to obtain the beam vibration frequencies and mode shapes. Influences of crack location and sizes on the natural frequencies for the cantilever beam, as well as the mode shapes, are analysed. An established FE model and test results in the listed references are used to validate the developed method.

Findings

The numerical results show that the rotational stiffness at the cracked section and the natural frequencies of the beam decrease by increasing the crack sizes; the natural frequencies for the beam are greatly influenced by the crack sizes and location; the first natural frequency decreases with the distance from the beam fixed end to the crack location; the value of the first natural frequency reaches a minimum value when the crack is at the beam fixed end; the value of the second natural frequency is a minimum value when the crack is at the beam middle; and the value of the third natural frequency is a minimum value when the crack is at the beam free end. Saltation is observed in some mode shapes at the crack location, especially for larger crack depths; but, the mode shapes of the beam are slightly influenced by the vertical crack.

Originality/value

This study gives a useful analytical modelling method for free vibration analysis for the cantilever beam with a vertical crack, which can overcome the disadvantages of the previous uniform crack methods.
Application of the peridynamic differential operator to the solution of sloshing problems in tanks
Authors: Bazazzadeh Soheil , Shojaei Arman , Zaccariotto Mirco , Galvanetto Ugo
Published: December 2018

Purpose

The purpose of this paper is to apply the Peridynamic differential operator (PDDO) to incompressible inviscid fluid flow with moving boundaries. Based on the potential flow theory, a Lagrangian formulation is used to cope with non-linear free-surface waves of sloshing water in 2D and 3D rectangular and square tanks.

Design/methodology/approach

In fact, PDDO recasts the local differentiation operator through a nonlocal integration scheme. This makes the method capable of determining the derivatives of a field variable, more precisely than direct differentiation, when jump discontinuities or gradient singularities come into the picture. The issue of gradient singularity can be found in tanks containing vertical/horizontal baffles.

Findings

The application of PDDO helps to obtain the velocity field with a high accuracy at each time step that leads to a suitable geometry updating for the procedure. Domain/boundary nodes are updated by using a second-order finite difference time algorithm. The method is applied to the solution of different examples including tanks with baffles. The accuracy of the method is scrutinized by comparing the numerical results with analytical, numerical and experimental results available in the literature.

Originality/value

Based on the investigations, PDDO can be considered a reliable and suitable approach to cope with sloshing problems in tanks. The paper paves the way to apply the method for a wider range of problems such as compressible fluid flow.
Building a culture of business analytics: a marketing analytics exercise
Authors: Haywood M. Elizabeth , Mishra Anubha
Published: December 2018

Purpose

The purpose of this paper is to describe how brief exercises in introductory and advanced marketing courses can help business students achieve a broader understanding of what Big data and data analytics mean in the workplace. These short analytics problems fit into the culture that we are building at our institution to create analytics cases for courses within our business curriculum.

Design/methodology/approach

A database of 1,500 customer reviews for a fictitious sporting company was created. Two exercises based on text mining and sentiment analysis were developed to be tested in introductory and advanced marketing course. Students were introduced to the basic concepts used in data analysis and the creation of R code for extracting sentiment words was demonstrated. Students then used pivot tables to identify patterns in the given data set. Students in the introductory course completed a short exercise while the students in the advanced class developed a detailed memo.

Findings

Results suggest that students in the introductory course are significantly more aware of the use of data in the industry as well as methods to deal with Big data after completing the exercise as compared to their knowledge at the beginning of the exercise. Students in the advanced course are able to identify patterns, detect shortcoming and propose strategic plans based on their analysis of the data.

Originality/value

Proposed exercises in the study are developed with an aim to help business schools develop a culture supportive of analytics. The purpose of these exercises is to make students aware of the importance of Big data and analytics early on in their curriculum and reinforce their exposure in an advanced course.
Female entrepreneurship in the Baltics: formal and informal context
Authors: Rugina Sanita
Published: December 2018

Purpose

This paper aims to review female entrepreneurship in a (post) transition context, analysing its almost three-decade development in Latvia, Lithuania and Estonia. Little research has focussed to date on female entrepreneurship in the Baltic countries. Using an institutional perspective, this paper aims to explain the unique interplay of formal and informal contexts that have shaped the development of female entrepreneurship in (post-) transition contexts.

Design/methodology/approach

This paper is based on an institutional reading and analysis of secondary data: statistical data, international reports and previous studies on female entrepreneurs.

Findings

There are more than 130,000 female entrepreneurs in the Baltic countries who share many common features and challenges. While the formal entrepreneurship environment is considered to be very developed in the Baltic countries, women are under-represented among the population of entrepreneurs, and there is gender-based sectoral segregation of female entrepreneurs in Estonia, Latvia and Lithuania. This indicates a need to recognise the diversity of patterns in entrepreneurial development, reflecting different inheritances from the Soviet past and the inertial character of some informal institutions, not to mention the differences in the pace of change during the transition period following the Soviet era.

Practical implications

This research can be used for academics, professionals, researchers and policymakers working in the fields of small business and entrepreneurship. Its data can furthermore be used to develop evidence-based policy and actions that would foster the participation of women in entrepreneurship in Baltic countries.

Originality/value

So far, little research has focussed on female entrepreneurship in the Baltic countries. The paper attempts to investigate that Baltic countries with their history of emphasis on gender equality on one hand and the award-winning business and entrepreneurship system on the other hand demonstrate relatively low levels of women’s entrepreneurship. This paper aims to contribute to the field of entrepreneurship, illustrating how entrepreneurship is linked to its social context.
The optimum size of rotating qarḍ ḥasan savings and credit associations
Authors: Sadr Seyed Kazem
Published: December 2018

Purpose

Several indigenous credit and savings schemes have been accredited recently in developing countries for the benefit of households and entrepreneurs alike. Famous among them are the Rotating Savings and Credit Associations (ROSCAs) that exist in almost all continents currently. The rapid development of ROSCAs and their varied structures in many countries have been the subject of numerous studies. What has not been thoroughly analysed is the optimum size of these associations and the fact that lending and borrowing is without interest. The aim of this paper is to present a model that would determine the optimum size of ROSCAs and deal with the following issues: how the group size varies with changes in the income level of the members, the demand for the loan, the size of the collected loan and its duration. Further, the question of whether or not lending to the association in return for obtaining larger sums is a violation of the qarḍ (loan) contract is dealt with, and several Sharīʿah compatible formulations are provided.

Design/methodology/approach

Economic analysis has been applied to show the optimum size of Qarḍ Ḥasan Associations (QHAs), which are the Sharīʿah-compliant equivalent of ROSCAs, and the Sharīʿah rules of the qarḍ contract to illustrate the legitimacy of group lending.

Findings

The major findings of this study are determination of the optimum size of QHAs, the factors that affect the size and suggestion of alternative legal forms for group financing.

Research limitations/implications

Inaccessibility to sources of data to test the hypothesis that has been put forth is the main difficulty encountered when conducting research on the subject.

Practical implications

The paper concludes that the development of informal interest-free ROSCAs in both Muslim and non-Muslim countries is an efficient informal microfinance scheme and that it is compatible with Sharīʿah rules.

Originality/value

The optimum size of ROSCAs and QHAs has been presented in this paper.
Purging of impure income: a comparative study of the existing purging methodologies
Authors: Shaik Mohammed Wasiullah , Barkatulla Mufti Abdul Kader , Khatkhatay Mohammed Husain , Abbas Zaffar
Published: December 2018

Purpose

The purpose of this paper is to study the concept of purging and present a comparative study of the existing purging methodologies prevailing in the market with a view to evolving a more effective method of capturing the entire impure income to be purged.

Design/methodology/approach

To illustrate the present discussion, a case study of purging based on numerical examples has been included. The argument has also been supported with empirical data related to the universe of Sharīʿah-compliant stocks listed on Indian stock exchanges.

Findings

During the study, it was found that the existing purging methodologies of calculating impure income to be purged have conceptual and practical shortcomings.

Research implications/limitations

The scope of the current research is limited to calculation of impure income which accrues on account of Sharīʿah non-compliant investments directly or indirectly. It does not try to quantify the benefit which may be imputed in the form of capital gains made in trading of the investee company shares due to higher market value of the shares as a result of the impure income earned by the investee company. The paper has focused on identifying and calculating the impure income on account of interest. Impure income earned from specific Sharīʿah non-compliant products or services has not been considered directly. The reason for this is that companies dealing in such products or services are generally excluded at the business screening stage itself. In the case of those companies which derive a relatively small proportion of their total income from such activities and pass the business screening stage, the quantum of the impure income is not generally reported separately in company accounts.

Practical implications/limitation

The result of adopting the proposed methodology will lead to complete purging of impure income (to the extent that is possible under present Company Law and stock exchange reporting regulations). Implementation of the proposed method requires a proper understanding of the working of listed companies and either a sound mathematical background or access to a software application to calculate the impure income to be purged.

Originality/value

The current paper is original and based on the authors’ personal understanding and experience of providing Sharīʿah consultancy services related to Sharīʿah-compliant investments.
Towards the establishment of cash waqf microfinance fund for refugees
Authors: Kachkar Omar Ahmad
Published: December 2018

Purpose

This paper aims to propose cash waqf (endowment) to develop a conceptual model that can be utilised to extend microfinance for refugees.

Design/methodology/approach

Qualitative method is used in this research. An extensive review of the literature has been conducted. Latest literature on refugees, microfinance has been critically examined beside the current cash waqf models.

Findings

Empirical studies have shown that many refugees are equipped with marketable skills and talents that can be utilised to improve their socio-economic situations. The proposed model – cash waqf refugee microfinance fund (CWRMF) – is structured to extend microfinance to potential refugee micro entrepreneurs. To address the lack of collateral, which is a requirement to gain any microfinance, CWRMF has been incorporated with a takaful unit (cooperation) by which refugees may guarantee each other. Additionally, the model has also been structured to address the challenge of sustainability of the institution that would provide microfinance. Hence, a reserve fund has also been integrated into the model.

Practical implications

CWRMF represents a potential model to be implemented by humanitarian non-governmental organisations (NGOs) and aid agencies to support livelihood of refugees in particular for Muslim refugees. Positive outcome is expected from the implementation of this model. This is because of the various advantages of microfinance programs not only on refugees but also on concerned NGOs, host populations and donor parties. Additionally, this paper is a set of primarily thoughts aims to open the door wider for more researchers to explore the potential of cash waqf as one of the instruments to finance refugee microenterprises and business activities.

Originality/value

Recently cash waqf has been into several models for socio-economic development and poverty alleviation. This paper is proposing cash waqf as a source for a microfinance fund that can contribute in the improvement of socio-economic situations of millions of refugees around the world.
Marketing on Instagram
Authors: Teo Li Xin , Leng Ho Keat , Phua Yi Xian Philip
Published: December 2018

Purpose

Social network sites are becoming more visual-centric. The purpose of this paper is to examine the effectiveness of visual social network sites as a marketing platform.

Design/methodology/approach

This paper comprises two experiments. The first experiment sought to examine the effect of social influence; while the second experiment examined the effect of image quality on the perception of quality and purchase intention.

Findings

The first experiment showed that social influence did not affect perceived quality or purchase intention. In the second experiment, a one-way between-groups multivariate analysis of covariance (MANCOVA) adjusting for sport involvement showed a statistically significant difference between the two groups. Respondents in the experimental group reported higher levels of perceived quality (adjusted M=3.68) and purchase intention (adjusted M=3.23) when compared to the control group’s perceived quality (adjusted M=3.12) and purchase intention (adjusted M=2.17).

Research limitations/implications

One of the limitations of this study is that it only examined the effects through a single social network site, i.e. Instagram. As there are other visual-centric social network sites, such as Tumblr and Pinterest, which operate slightly different from Instagram, it remains to be established how such effects vary across these social network sites.

Practical implications

The results suggest that social influence on Instagram is limited and marketers should invest in images of high quality when marketing on visual social network sites.

Originality/value

While there are many studies examining the effectiveness of marketing on social network sites, these studies have primarily focussed on earlier social network sites, such as Facebook. Newer social network sites that are more visual-centric, such as Instagram, are different from earlier social network sites and studied to a lesser extent. This study adds insights on the marketing effectiveness of visual-centric social network sites and deepens the understanding on marketing in general on social media.
Public procurement re-examined
Authors: Thai Khi V.
Published: December 2018

Academically, public procurement has been a neglected area of study even though governmental entities and public procurement practitioners have diligently worked to improve public procurement practices. This article will identify common elements of public procurement knowledge through a brief analysis of the literature and will provide a summary of government efforts to improve public procurement practices. In addition, this article will comprehensively re-examine public procurement by using a systems approach as a method of inquiry. Finally, implications of the proposed public procurement system regarding future research and study will be discussed.
Choosing the open or the restricted procedure: A

big

deal or a big

deal

?
Authors: Heijboer Govert , Telgen Jan
Published: December 2018

The legislation in the European Union (EU) regarding contracts to be awarded to third parties allows for a free choice by public agencies between the open and restricted procedure. Empirical evidence shows a high variance in the preference for one of the procedures exists between countries. This preference may be based on cultural phenomena only. Here we develop a quantitative model to calculate which procedure is the most economic. With insights from this model guidelines are given for an efficient policy regarding the choice for the open or restricted award procedure.
A comparison of purchasing’s organizational roles and responsibilities in the public and private sector
Authors: Johnson P. Fraser , Leenders Michiel R. , McCue Clifford
Published: December 2018

This research focuses on a comparison of public and private sector supply organizations in terms of organizational structure, supply chain responsibilities, the chief purchasing officer (CPO) and reporting line, teaming and involvement in major organizational activities. A unique opportunity to identify similarities and differences was presented in 2000 when the National Institute of Governmental Purchasing Research (NIGP) and Florida Atlantic University replicated in the public sector a study that the Center for Advanced Purchasing Studies (CAPS) conducted in the private sector in 1995. Significant differences and similarities are identified and are discussed in this paper.
P-card utilization in municipal government: advantages and concerns
Authors: Daly John L. , Buehner Michael A.
Published: December 2018

P-card (i.e., procurement card) programs have been praised as innovative means for procurement systems to save fiscal resources for municipal government while granting greater purchasing discretion for departmental endusers. Using Hillsborough County (Tampa), Florida as a case study, the authors identify four critical factors that influence the successful implementation of municipal P-card systems. In the final analysis, the authors suggest that the distinction between organizational success and failure for these programs is likely to be a factor of organizational commitment more than technical capacity.