bluuebunny/crossref_metadata_2025 huggingface dataset:
Daptomycin Use in Children: Experience With Various Types of Infection and Age Groups
Authors: Syrogiannopoulos George A. , Michoula Aspasia N. , Petinaki Efthimia , Grivea Ioanna N.
Published: May 2017

Background:

In Greece, there are high rates of methicillin (40%–60%) and clindamycin (15%–25%) resistance among community-acquired Staphylococcus aureus isolates. Therefore, we sought to identify other antimicrobial treatment options such as daptomycin.

Methods:

We studied retrospectively all pediatric infections treated with daptomycin at the University General Hospital of Larissa, Greece, from January 1, 2007, to June 16, 2016.

Results:

Of a total of 128 patients (median age: 2.8 years; range: 8 days to 14.5 years; 76.6% <7 years) treated with daptomycin, 45 (35.2%) had invasive infection, most frequently musculoskeletal, and 83 (64.8%) had noninvasive infection, that is, complicated skin and soft tissue infection. S. aureus was the most commonly recovered pathogen (n = 61) (63.9% methicillin-resistant isolates, 21.3% clindamycin-resistant). The average daily dose of daptomycin was 10 mg/kg qd, and the median duration of therapy was 10 days. Daptomycin was administered alone (n = 61) or in combination therapy (n = 67), most frequently with rifampin (n = 40) and/or a β-lactam antibiotic (n = 33). Open or closed drainage was performed in 86 (67.2%) of the total number of patients. Of 128 treated patients, 123 (96.1%) achieved clinical success, 114 (89.1%) had complete remission, and 9 (7%) had improvement of their disease. There were no failures with daptomycin therapy. The adverse events were of no clinical significance.

Conclusions:

Daptomycin administered alone or in combination with other antimicrobial agents to children was efficacious and well tolerated in the treatment of complicated infections of suspected or proven staphylococcal etiology.
Polymorphisms in the vitamin D receptor gene are associated with reduced rate of sputum culture conversion in multidrug-resistant tuberculosis patients in South Africa
Authors: Magee Matthew J , Sun Yan V. , Brust James CM , Sarita Shah N. , Ning Yuming , Allana Salim , Campbell Angela , Hui Qin , Mlisana Koleka , Moodley Pravi , Gandhi Neel R
Published: May 2017

Background

Vitamin D modulates the inflammatory and immune response to tuberculosis (TB) and also mediates the induction of the antimicrobial peptide cathelicidin. Deficiency of 25-hydroxyvitamin D and single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene may increase the risk of TB disease and decrease culture conversion rates in drug susceptible TB. Whether these VDR SNPs are found in African populations or impact multidrug-resistant (MDR) TB treatment has not been established. We aimed to determine if SNPs in the VDR gene were associated with sputum culture conversion among a cohort of MDR TB patients in South Africa.

Methods

We conducted a prospective cohort study of adult MDR TB patients receiving second-line TB treatment in KwaZulu-Natal province. Subjects had monthly sputum cultures performed. In a subset of participants, whole blood samples were obtained for genomic analyses. Genomic DNA was extracted and genotyped with Affymetrix Axiom Pan-African Array. Cox proportional models were used to determine the association between VDR SNPs and rate of culture conversion.

Results

Genomic analyses were performed on 91 MDR TB subjects enrolled in the sub-study; 60% were female and median age was 35 years (interquartile range [IQR] 29-42). Smoking was reported by 21% of subjects and most subjects had HIV (80%), were smear negative (57%), and had cavitary disease (55%). Overall, 87 (96%) subjects initially converted cultures to negative, with median time to culture conversion of 57 days (IQR 17-114). Of 121 VDR SNPs examined, 10 were significantly associated (p<0.01) with rate of sputum conversion in multivariable analyses. Each additional risk allele on SNP rs74085240 delayed culture conversion significantly (adjusted hazard ratio 0.30, 95% confidence interval 0.14-0.67).

Conclusions

Polymorphisms in the VDR gene were associated with rate of sputum culture conversion in MDR TB patients in this high HIV prevalence setting in South Africa.

Author contributions

MJM, YVS, JCMB, SS, and NRG conceived and designed the study and drafted the initial manuscript. MJM, YVS, YN, and QH performed the data analyses. All authors contributed to interpretation of the data, revised the manuscript, and approved the final version.

The findings and conclusions in this article are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention (CDC). The use of trade names and commercial sources is for identification only and does not imply endorsement by the CDC.
High-Resolution Epidemic Simulation Using Within-Host Infection and Contact Data
Authors: Nguyen Van Kinh , Mikolajczyk Rafael , Hernandez-Vargas Esteban A.
Published: May 2017

Background

Transmission in epidemics of infectious diseases is characterized by a high level of subject-specific elements. These include heterogeneous infection conditions, time-dependent transmission potential, and age-dependent contact structure. These insights are often lost in epidemic models using population data. Here we submit an approach that can capture these details, paving the way for studying epidemics in a more mechanistic and realistic way.

Methods

Using experimental data, we formulated mathematical models of a pathogen infection dynamics from which we can simulate its transmission potential mechanistically. The models were then embedded in our implement of an age-specific contact network structure that allows to express all elements relevant to the transmission process. This approach is illustrated here with an example of Ebola virus (EBOV).

Results

The results showed that within-host infection dynamics can capture EBOV’s transmission parameters as good as approaches using population data. Population age-structure, contact distribution and patterns can also be captured with our network generating algorithm. This framework opens vast opportunities for the investigations of each element involved in the epidemic process. Here, estimating EBOV’s reproduction number revealed a heterogeneous pattern among age-groups, prompting questions on current estimates which are not adjusted for this factor. Assessments of mass vaccination strategies showed that a time window from five months before to one week after the start of an epidemic appeared to be effective. Noticeably, compared to a non-intervention scenario, a low vaccination coverage of 33% could reduce number of cases by ten to hundred times as well as lessen the case-fatality rate.

Conclusions

This is the first effort coupling directly within-host infection model into an age-structured epidemic network model, adding more realistic elements in simulating epidemic processes. Experimental data at the within-host infection are shown able to capture upfront key parameters of a pathogen; the applications of this approach will give us more time to prepare for potential epidemics. Population of interest in epidemic assessments could be modeled with an age-specific contact network without exhaustive amount of data. Further assessments and adaptations for different pathogens and scenarios are underway to explore multilevel aspects in infectious diseases epidemics.
A safer, urea-based in situ hybridization method improves detection of gene expression in diverse animal species
Authors: Sinigaglia Chiara , Thiel Daniel , Hejnol Andreas , Houliston Evelyn , Leclère Lucas
Published: May 2017

In situ hybridization is a widely employed technique allowing spatial visualization of gene expression in fixed specimens. It has proven to be essential to our understanding of biological processes, including developmental regulation. In situ protocols are today routine in numerous laboratories, and although details might change, they all include a hybridization step, where specific antisense RNA or DNA probes anneal to the target nucleic acids strand. This step, in general, is carried out at high temperatures and in a denaturing solution, the hybridization buffer, commonly containing 50% (v/v) formamide. An important drawback is that hot formamide poses a significant health risk and so must be handled with great care.

We were prompted to test alternative hybridization solutions for in situ detection of gene expression in the medusa of the hydrozoanClytia hemisphaerica,where traditional protocols caused extensive deterioration of the morphology and texture during hybridization, hindering observation and interpretation of results. Inspired by optimized protocols for Northern and Southern blot analysis, we substituted the 50% formamide with an equal volume of 8 M urea solution in the hybridization buffer. The new protocol yielded better morphologies and consistency of tissues, and also notably improved the resolution of the signal, allowing more precise localization of gene expression, as well as reduced staining at non-specific sites. Given the improved results using a less toxic hybridization solution, we tested the urea protocol on a number of other metazoans: two brachiopod species (Novocrania anomalaandTerebratalia transversa) and the wormPriapulus caudatus,obtaining a similar reduction of aspecific probe binding. Overall, substitution of formamide by urea in in situ hybridization offers safer alternative protocols, potentially useful in research, medical and teaching contexts. We encourage other workers to test this approach on their study organisms, and hope that they will also obtain better sample preservation, more precise expression patterns and fewer problems due to aspecific staining, as we report here forClytiamedusae andNovocraniaandTerebrataliadeveloping larvae.
The spectral features of EEG responses to transcranial magnetic stimulation of the primary motor cortex depend on the amplitude of the motor evoked potentials
Authors: Fecchio Matteo , Pigorini Andrea , Comanducci Angela , Sarasso Simone , Casarotto Silvia , Premoli Isabella , Derchi Chiara-Camilla , Mazza Alice , Russo Simone , Resta Federico , Ferrarelli Fabio , Mariotti Maurizio , Ziemann Ulf , Massimini Marcello , Rosanova Mario
Published: May 2017

Transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) can excite both cortico-cortical and cortico-spinal axons resulting in TMS-evoked potentials (TEPs) and motor-evoked potentials (MEPs), respectively. Despite this remarkable difference with other cortical areas, the influence of motor output and its amplitude on TEPs is largely unknown. Here we studied TEPs resulting from M1 stimulation and assessed whether their waveform and spectral features depend on the MEP amplitude. To this aim, we performed two separate experiments. In experiment 1, single-pulse TMS was applied at the same supra-threshold intensity on primary motor, prefrontal, premotor and parietal cortices and the corresponding TEPs were compared by means of local mean field power and time-frequency spectral analysis. In experiment 2 we stimulated M1 at resting motor threshold in order to elicit MEPs characterized by a wide range of amplitudes. TEPs computed from high-MEP and low-MEP trials were then compared using the same methods applied in experiment 1. In line with previous studies, TMS of M1 produced larger TEPs compared to other cortical stimulations. Notably, we found that only TEPs produced by M1 stimulation were accompanied by a late (∼300 ms after TMS) event-related desynchronization (ERD), whose magnitude was strongly dependent on the amplitude of MEPs. Overall, these results suggest that M1 produces peculiar responses to TMS possibly reflecting specific anatomo-functional properties, such as the re-entry of proprioceptive feedback associated with target muscle activation.
Dissociable neural information dynamics of perceptual integration and differentiation during bistable perception
Authors: Canales-Johnson Andrés , Billig Alexander J. , Olivares Francisco , Gonzalez Andrés , del Carmen Garcia María , Silva Walter , Vaucheret Esteban , Ciraolo Carlos , Mikulan Ezequiel , Ibanez Agustín , Huepe David , Chennu Srivas , Bekinschtein Tristan A.
Published: May 2017

At any given moment, we experience a perceptual scene as a single whole and yet we may distinguish a variety of objects within it. This phenomenon instantiates two properties of conscious perception: integration and differentiation. Integration to experience a collection of objects as a unitary percept, and differentiation to experience these objects as distinct from each other. Here we evaluated the neural information dynamics underlying integration and differentiation of perceptual contents during bistable perception. Participants listened to a sequence of tones (auditory bistable stimuli) experienced either as a single stream (perceptual integration) or as two parallel streams (perceptual differentiation) of sounds. We computed neurophysiological indices of information integration and information differentiation with electroencephalographic and intracranial recordings. When perceptual alternations were endogenously driven, the integrated percept was associated with an increase in neural information-integration and a decrease in neural differentiation across frontoparietal regions, whereas the opposite pattern was observed for the differentiated percept. However, when perception was exogenously driven by a change in the sound stream (no bistability) neural oscillatory power distinguished between percepts but information measures did not. We demonstrate that perceptual integration and differentiation can be mapped to theoretically-motivated neural information signatures, suggesting a direct relationship between phenomenology and neurophysiology.
Predicting Morphological Disparities in Sea Urchin Skeleton Growth and Form
Authors: Abou Chakra Maria , Lovric Miroslav , Stone Jonathon
Published: May 2017

Sea urchins exhibit among their many species remarkable diversity in skeleton form (e.g., from spheroid to discoid shapes). However, we still do not understand how some related species show distinct morphologies despite inherent similarities at the genetic level. For this, we use theoretical morphology to disentangle the ontogenic processes that play a role in skeletal growth and form. We developed a model that simulates these processes involved and predicted trajectory obtaining 94% and 77% accuracies. We then use the model to understand how morphologies evolved by exploring the individual effects of three structures (ambulacral column, plate number, and polar regions). These structures have changed over evolutionary time and trends indicate they may influence skeleton shape, specifically height–to-diameter ratio, h:d. Our simulations confirm the trend observed but also show how changes in the attributes affect shape; we show that widening the ambulacral column or increasing plate number in columns produces a decrease in h:d (flattening); whereas increasing apical system radius to column length ratio produces an increase in h:d (gloublar shape). Computer simulated h:d matched h:d measured from real specimens. Our findings provide the first explanation of how small changes in these structures can create the diversity in skeletal morphologies.
A germline FANCA alteration that is associated with increased sensitivity to DNA damaging agents
Authors: Wilkes David C. , Sailer Verena , Xue Hui , Cheng Hongwei , Collins Colin C. , Gleave Martin , Wang Yuzhuo , Demichelis Francesca , Beltran Himisha , Rubin Mark A. , Rickman David S.
Published: May 2017

Defects in genes involved in DNA damage repair (DDR) pathway are emerging as novel biomarkers and targets for new prostate cancer drug therapies. A previous report revealed an association between an exceptional response to cisplatin treatment and a somatic loss of heterozygosity (LOH) of FANCA in a patient with metastatic prostate cancer who also harbored a germline FANCA variant (S1088F). Although germline FANCA mutations are the most frequent alterations in patients with Fanconi anemia, germline alterations are less common in prostate cancer. We hypothesized that the germline S1088F FANCA variant in combination with FANCA LOH was deleterious for FANCA function and contributed to the patient's exceptional response to cisplatin. We show that although it properly localizes to the nucleus, the S1088F FANCA mutant protein disrupts the FANC protein complex resulting in increased sensitivity to DNA damaging agents. Because molecular stratification is emerging as a strategy for treating men with metastatic, castrate-resistant prostate cancer harboring specific DDR gene defects, our findings suggest that more biomarker studies are needed to better define clinically relevant germline and somatic alterations.
The financial gap for women in the MENA region: a systemic perspective
Authors: Saviano Marialuisa , Nenci Luisa , Caputo Francesco
Published: May 2017

Purpose

This paper aims to investigate women’s financial inclusion as a critical element for the competitiveness of the Middle East and North Africa (MENA) market for entrepreneurship and sustainable development of the region, as MENA financial institutions’ loans to women-owned SMEs tend to be significantly lower than the share of women-owned SMEs in their target markets. Causes of under-serving this market are not very well studied.

Design/methodology/approach

The paper builds on an inductive approach supported by the interpretative contribution offered by the viable systems approach as methodological and interpretative lens to investigate the topic of women financial inclusion in MENA regions. Reflections herein are supported by an exploratory study on the conditions for women financial inclusion in MENA regions.

Findings

The main focus of this paper is to study the financial gap that women entrepreneurs are experiencing in enlarging their businesses and/or lunching innovative projects. In accordance with this, the paper highlights the need of a more systemic approach and long-term vision to support a more extensive women financial inclusion in MENA regions.

Originality/value

Financial institutions’ need to understand women-owned SMEs’ financial needs for innovation and growth to build new customized financial products. This paper’s argument is that the dominant short-term approach to credit-granting for women, although providing support, may be inadequate to achieve a real financial inclusion, and possible causes and solutions are discussed.
Conflict management systems for large scientific research projects
Authors: Löhr Katharina , Graef Frieder , Bonatti Michelle , Mahoo Henry F. , Wambura Jane , Sieber Stefan
Published: May 2017

Purpose

This paper aims to analyze the transferability of a conflict management model developed for business organizations to a temporary and international research project to serve as a support tool for internal communication and in case of conflict.

Design/methodology/approach

The authors analyze the transferability of a conflict management model that was initially developed for business organizations to an international, inter-organizational and temporary research project that is third-party funded. Using a case study, a participatory approach is applied with both qualitative and quantitative methods used.

Findings

The transferability is possible but only with the adaption of conflict prevention. The project’s international and inter-organizational structure further results in a need for decentralization of conflict management responsibilities and diversification of conflict management approaches. Time, financial resources and a high autonomy of cooperation partners limit the degree of participation in the design process.

Research limitations/implications

The research is based on a case study. Research on comparative design processes are needed to verify or extrapolate findings and to help assess the impact of conflict management systems in other large research projects.

Originality/value

This paper contributes to the body of knowledge on conflict management systems. By implementing a conflict management system in a temporary, international and scientific project environment, this case study identifies contextual factors relevant for the system design and provides initial test results. As conflict management systems in research projects are not yet prominent, this adapted model of conflict prevention and management can benefit similar projects.
Adaptive mediation: an evidence-based contingency approach to mediating conflict
Authors: Coleman Peter T. , Kugler Katharina G. , Chatman Ljubica
Published: May 2017

Purpose

Although mediation has increased considerably in popularity and usage, it lacks a coherent framework and evidence base to illuminate the conditions under which different types of mediation strategies are most effective. This has resulted in a wide array of strategies and tactics being offered to mediators, with little sense of which may work best under different conditions. This paper aims to further develop a contingency model of adaptive mediation.

Design/methodology/approach

The current paper extends previous research on adaptive mediation by presenting findings from focus group and survey research with experienced mediators that help to further develop and specify a new adaptive model of mediation.

Findings

The findings support the utility of a contingency model of adaptive mediation based on the four fundamental dimensions of mediation situations (conflict intensity, situational constraints, cooperative vs competitive disputant relationships and overt vs covert issues and processes) for better understanding and predicting changes in mediator strategies independent of mediator style preferences.

Research limitations/implications

The present studies reflect the behavioral tactics experienced mediators recommend when facing the four distinct challenges to mediation. Research has yet to determine whether the sets of tactics recommended would actually be more successfully used in mediations presenting the four challenges. Subsequent research should assess the relative effects of the use of the different behavioral strategies under these conditions.

Originality/value

The program of research described and extended in this paper is an attempt to develop an integrative model of adaptive mediation, which can ultimately enhance the critical link between mediation research on the one hand and mediation practice on the other.
Managed care Medicaid
Authors: Trombetta William
Published: May 2017

Purpose

Providing health care to the poor is evolving in the new US marketplace. The Affordable Care Act has set goals enhancing access to health care, lowering costs and improving patient outcomes. A key segment in this evolution is the most vulnerable health-care population of all: Medicaid. This paper aims to provide a general review of how providing health care to Medicaid patients is changing including how socio-economic aspects of this vulnerable population affects the quality of the health care provided.

Design/methodology/approach

The paper is entirely secondary research; no primary research has been conducted.

Findings

Managed care Medicaid provides a risk-based model to treating a vulnerable health-care market segment. The jury is still out on whether managed care Medicaid (MCM) is improving health-care quality and saving cost, but the provision of health care to the Medicaid segment is definitely shifting from a fee-for-service model to value based payment. Very recent developments of new health-care delivery approaches present a positive outlook for improving quality and containing costs going forward.

Research limitations/implications

At this stage, whether or not MCM saves money or provides better health-care quality to this vulnerable population is a work in progress. Health-care marketing can impact socio-economic aspects of health care for the poor. There is a need to follow up on the positive results being documented in demonstration health-care delivery models.

Practical implications

At this point, there has been no long-term study of whether managed care Medicaid offers better quality of health care and cost savings. The research to date suggest that the quality of health-care delivery to the poor is improving at a lower cost to payers.

Social implications

Medicaid patients are an underserved market segment. Managed care Medicaid offers a new model that has the potential to provide quality care at acceptable cost. Critical to this vulnerable market segment is the need to integrate socio-economic aspects of the population with the delivery of health care.

Originality/value

There has been very little discussion of Medicaid overall in the marketing literature, much less any discussion of managed care Medicaid.
The new deflation and housing market bubbles in the USA and UK: a monetary policy dilemma
Authors: Bono Heather Richardson , Leathers Charles G. , Raines J. Patrick
Published: May 2017

Purpose

The purpose of this paper is to develop an analysis of the improbable events of housing market bubbles occurring in a period when US and UK central bankers were responding to perceived risks of a new deflation.

Design/methodology/approach

The methodology focuses on how the anti-deflation policies implemented by the Federal Reserve and the Bank of England contributed to the housing market bubbles. The central bankers perceived the deflation as a Keynesian short-run deficiency in aggregate demand, triggered by a financial crisis. Indications are that the deflation is in the nature of long-run aggregate-supply-driven trend as explained in Veblen’s theory of “chronic” deflation driven by cost-reducing advances in technology and globalization.

Findings

The Keynesian anti-deflation policies of the Federal Reserve and Bank of England failed to counter the deflation risks while contributing to housing market bubbles. Moreover, the policies failed to address the structural problems of unemployment and income inequality associated with long-run aggregate supply deflation.

Originality/value

Effective policies must be based on a correct theoretical understanding of the problems. The chronic nature of the new deflation points to the need for new approaches to deal with the negative income and employment effects that exclude an increasing number from the housing markets.
A semantic-syntax model for XML query construction
Authors: Gan Keng Hoon , Phang Keat Keong
Published: May 2017

Purpose

When accessing structured contents in XML form, information requests are formulated in the form of special query languages such as NEXI, Xquery, etc. However, it is not easy for end users to compose such information requests using these special queries because of their complexities. Hence, the purpose of this paper is to automate the construction of such queries from common query like keywords or form-based queries.

Design/methodology/approach

In this paper, the authors address the problem of constructing queries for XML retrieval by proposing a semantic-syntax query model that can be used to construct different types of structured queries. First, a generic query structure known as semantic query structure is designed to store query contents given by user. Then, generation of a target language is carried out by mapping the contents in semantic query structure to query syntax templates stored in knowledge base.

Findings

Evaluations were carried out based on how well information needs are captured and transformed into a target query language. In summary, the proposed model is able to express information needs specified using query like NEXI. Xquery records a lower percentage because of its language complexity. The authors also achieve satisfactory query construction rate with an example-based method, i.e. 86 per cent (for NEXI IMDB topics) and 87 per cent (NEXI Wiki topics), respectively, compare to benchmark of 78 per cent by Sumita and Iida in language translation.

Originality/value

The proposed semantic-syntax query model allows flexibility of accommodating new query language by separating the semantic of query from its syntax.
Guidelines and deployment of accessibility-aware framework approach
Authors: Ali Saqib , AlBalushi Taiseera , AlBadi Ali
Published: May 2017

Purpose

The purpose of this research is to facilitate the full potential of the web for the people with disabilities. People with disabilities may fail to make full use of the potentials offered by the web even if they have the right hardware (computer and assistive technologies) as well as access to the internet because of the lack of accessibility.

Design/methodology/approach

This research outlines the guidelines that provide the foundation for building an accessibility-aware framework approach, where people with disabilities can access most of the electronic contents based on their disability levels.

Findings

The framework helps web engineers in developing accessible web pages for all types of users. Disability profile examples (blindness, low vision, deafness and hard of hearing) were taken to determine the performance of the framework approach.

Research limitations/implications

The validation and testing was carried out on the Sultan Qaboos University website. The framework approach could be further validated by performing the tests on various other public and private websites.

Practical implications

The guidelines can be used as a road map to overcome accessibility challenges during any web application development life cycle. A proper testing and evaluation is carried out on the framework to test its usability.

Social implications

Although people with disabilities are perhaps the segment of society which are expected to gain the most from these technologies, they are facing barriers to access the contents of the web because of the way it is presented. This proposed framework could assist all the people with the disability of blindness and hearing impairment to have a better experience with the internet, making the technology more beneficial and usable to them. In the future, this approach can be extended for the people with other disabilities.

Originality/value

This research provides a pioneering concept for accessibility-aware framework approach. This approach could be utilized for developing accessible web applications and electronic services for people with disabilities. The proposed framework can be used as a road map to overcome accessibility challenges during any web application development life cycle.
A quality-controlled logic-based clustering approach for web service composition and verification
Authors: Huynh Khai Tan , Quan Tho Thanh , Bui Thang Hoai
Published: May 2017

Purpose

Service-oriented architecture is an emerging software architecture, in which web service (WS) plays a crucial role. In this architecture, the task of WS composition and verification is required when handling complex requirement of services from users. When the number of WS becomes very huge in practice, the complexity of the composition and verification is also correspondingly high. In this paper, the authors aim to propose a logic-based clustering approach to solve this problem by separating the original repository of WS into clusters. Moreover, they also propose a so-called quality-controlled clustering approach to ensure the quality of generated clusters in a reasonable execution time.

Design/methodology/approach

The approach represents WSs as logical formulas on which the authors conduct the clustering task. They also combine two most popular clustering approaches of hierarchical agglomerative clustering (HAC) and k-means to ensure the quality of generated clusters.

Findings

This logic-based clustering approach really helps to increase the performance of the WS composition and verification significantly. Furthermore, the logic-based approach helps us to maintain the soundness and completeness of the composition solution. Eventually, the quality-controlled strategy can ensure the quality of generated clusters in low complexity time.

Research limitations/implications

The work discussed in this paper is just implemented as a research tool known as WSCOVER. More work is needed to make it a practical and usable system for real life applications.

Originality/value

In this paper, the authors propose a logic-based paradigm to represent and cluster WSs. Moreover, they also propose an approach of quality-controlled clustering which combines and takes advantages of two most popular clustering approaches of HAC and k-means.
Demarcation boundary between region dominated by elastohydrodynamic lubrication and that by the surface force action for different elliptical ratios
Authors: Abd Al-Samieh Mohamed
Published: May 2017

Purpose

This paper aims to investigate the effect of changing speed of the entraining motion on the formation of ultra-thin lubricating films under different elliptical ratios. The ellipticity parameter (K) varied from 1 (a ball-on-plate configuration) to 6 (a configuration approaching line contact). The influence of the ellipticity parameters, the dimensionless speed and the effects of surface forces on the formation of the minimum film thickness has been demonstrated. The demarcation boundary between region dominated by elastohydrodynamic lubrication (EHL) and that by the surface force action has been demonstrated for different elliptical ratios.

Design/methodology/approach

The numerical solution has been carried out, using the Newton–Raphson iteration technique, applied for the convergence of the hydrodynamic pressure. The film thickness and pressure distribution are obtained by simultaneous solution of the Reynolds’ equation, the elastic deformation (caused by hydrodynamic pressure, surface force of solvation and Van der Waals force) and the load balance equation. The operating conditions, load and speed of entraining motion, promote formation of ultra-thin films that are formed under the combined action of EHL, surface contact force of solvation and molecular interactions due to presence of Van der Waals force.

Findings

The paper provides insights about the transition between region dominated by EHL and that by the surface force action for changing ellipticity ratio (K) from 1 (a ball-on-plate configuration) to 6 (a configuration approaching line contact).

Originality/value

This paper fulfils an identified need to study the effect of changing ellipticity ratio on the formation of ultra-thin films that are formed under the combined action of EHL, surface contact force of solvation and molecular interactions due to presence of Van der Waals force.
Study on the frictional performance of slide and plateau honed cylinder liners during running-in
Authors: Hu Yang , Meng Xianghui , Xie Youbai , Fan Jiazheng
Published: May 2017

Purpose

During running-in, the change in the honed cylinder liner surface alters the performance and efficiency of the piston ring-pack system. The present paper, thus, aims to investigate the surface topography and wear and friction evolution of a cylinder liner surface during the running-in tests on a reciprocating ring–liner tribometer under a mixed lubrication regime. After an initial period of rapid wear termed “running-in wear”, a relatively long-term steady-state surface topography can emerge. A numerical model is developed to predict the frictional performance of a piston ring-pack system at the initial and steady-state stages.

Design/methodology/approach

The liner surfaces are produced by slide honing (SH) and plateau honing (PH). The bearing area parameter (Rk family), commonly used in the automotive industry, is used to quantitatively characterize the surface topography change during the running-in process. A wear volume-sensitive surface roughness parameter, Rktot, is used to show the wear evolution.

Findings

The experimental results show that a slide-honed surface leads to reduced wear, and it reduces the costly running-in period compared to the plateau-honed surface. The simulation results show that running-in is a beneficial wear process that leads to a reduced friction mean effective pressure at the steady-state.

Originality/value

To simulate the mixed lubrication performance of a ring–liner system with non-Gaussian roughness, a one-dimensional homogenized mixed lubrication model was established. The real surface topography instead of its statistical properties is taken into account.
Extending Hertz equation for an elastic contact between a layered cylindrical hollow roller and flat plate through an experimental technique
Authors: Solanki Mitul Thakorbhai , Vakharia Dipak
Published: May 2017

Purpose

The purpose of this paper is to extend the Hertz equation for the contact interaction between a layered cylindrical hollow roller and a flat plate through an experimental technique.

Design/methodology/approach

In this work, an experimental investigation is carried out for an elastic contact between layered cylindrical hollow rollers of different hollowness, ranging from 30 to 75 per cent hollowness and a flat plate. The footprint method was used for the evaluation of the contact width corresponding to the applied load.

Findings

The contact width for the layered cylindrical hollow roller was evaluated and the Hertz equation was extended on the basis of the experimental results.

Originality/value

The value of this research work is the development of an extended Hertz equation for a cylinder-on-plate configuration for a new kind of cylindrical roller.
Effect of unleaded gasoline blended with biofuels on gasoline injector wear and exhaust emissions
Authors: Peng De-Xing
Published: May 2017

Purpose

To prolong engine life and reduce exhaust pollution caused by gasoline engines, the aim of this paper was to compare the lubrication properties of biofuel (ethanol) blends and pure unleaded gasoline.

Design/methodology/approach

Biofuels with a concentration of 0, 1, 2, 5 and 10 per cent were added to unleaded gasoline to form ethanol-blended fuels named E0, E1, E2, E5 and E10. Next, the ethanol-blended fuels and unleaded gasoline were used to power engines to facilitate comparisons between the pollution created from exhaust emissions.

Findings

Using ethanol as a fuel additive in pure unleaded gasoline improves engine performance and reduces exhaust emissions. Because bioethanol does not contain lead but contains low aromatic and high oxygen content, it induces more complete combustion compared with conventional unleaded gasoline.

Originality/value

Using biofuels as auxiliary fuel reduces environmental pollution, strengthens local agricultural economy, creates employment opportunities and reduces demand for fossil fuels.
Tribological performance of three surface-modified piston rings matched with chromium-plated cylinder liner
Authors: Zhu Feng , Xu Jiujun , Han Xiaoguang , Shen Yan , Jin Mei
Published: May 2017

Purpose

The paper aims to investigate the friction and wear properties of three surface-modified piston rings matched with a chromium-plated cylinder liner.

Design/methodology/approach

Samples were taken from the chromium-plated cylinder liner, Cr-Al2O3 ring, CrN ring and Mo ring. Tribo-tests were conducted on a reciprocating sliding tribometer under fully formulated engine oils. Friction coefficients and wear depths of three friction pairs were tested. Surface morphologies of cylinder liners and piston rings before and after test were analyzed.

Findings

Experimental results show that in the Cr-Al2O3 piston ring, scuffing occurred easily when matched with the chromium-plated cylinder liner; compared with the Mo ring, the CrN ring could decrease the wear depth of the piston ring from 2.7 to 0.2 μm, and the wear depth of cylinder liner remained; however, the friction coefficient increased from 0.113 to 0.123. The tribological performances of three surface-modified piston rings were significantly different when they matched with chromium-plated cylinder liner.

Originality/value

Chromium-plated cylinder liner and the three kinds of surface-modified piston rings have excellent friction and wear properties, respectively. However, according to the systematic characteristics of internal combustion (IC) engine tribology, only the appropriate cylinder liner–piston ring can improve the tribological performance of the IC engine. This paper reports the tribological performance of three surface-modified piston rings matched with a chromium-plated cylinder liner. The results can be used as reference for the design of high-power-density diesel engine.
The business actor and business management
Authors: Munksgaard Kristin B. , Ford David
Published: May 2017

Purpose

IMP literature has developed the conceptualisation of a business landscape comprised of varying combinations of more or less interdependent activities, resources and actors, the form of which are defined by the interactive processes in which they are involved. However, the conceptualisation of the interactively defined business actor presents challenges to the understanding of the nature of business and the process of management. The purpose of this paper is to discuss what it is to be a manager in the complex interactive business landscape and the capabilities needed by business managers.

Design/methodology/approach

Few, if any, IMP studies have systematically addressed the concept of the business actor directly and the authors do not have a well-developed framework for analysing actors from the perspectives of interaction and networks. This paper analyses the evolving semantics of the concepts of the interactive business actor within some of the literature associated with the IMP research tradition, using the software Leximancer.

Findings

The paper integrates the analysis into a preliminary framework for describing the characteristics of the interactive business actor. The paper concludes by using this framework to suggest some of the capabilities that are required by the interactive business actor.

Originality/value

The analysis points to the ways that ideas of the business actor and business acting have developed in the literature. The analysis highlights some of the ways in which the development of these concepts is incomplete and points to potentially fruitful ways in which conceptual and empirical research could proceed.
Understanding business networks from a mixed network and system ontology position
Authors: Prenkert Frans
Published: May 2017

Purpose

The purpose of this paper is to highlight the ontological implications of combining network and system ontology to conceptualize industrial networks as the empirical manifestations of complex adaptive economic systems.

Design/methodology/approach

This paper contributes with a systematic discussion on how network and system ontology can be combined to produce better understandings of business networks. It also provides a review of the state-of-the art research literature on the topic as a starting point for the discussion.

Findings

Findings indicate that networks may be enclosed in each other constituting sub- and supra-networks comprising increasing complexity. In these cases, sub-networks that are black-boxed can be seen as entities in themselves producing inputs and outputs to the supra-network. Networks, once they become black-boxed, can assume the functions of generative mechanisms within a wider supra-network.

Research limitations/implications

This research is conceptual in nature and needs to be complemented with empirical research. In addition, the literature review used one database complemented with papers from theIMPjournal. A wider search could reveal additional research that can be of relevance for the development of the field.

Originality/value

This paper addresses the ontological and methodological issues arising from a mixed system and network ontology. These issues are commonly ignored or dealt with indirectly in extant literature. For any accumulation of knowledge in the field to be possible, the explication of a mixed ontology is important as it have conceptual and methodological consequences. Adopting such a mixed ontological position provides an ontology in line with empirical research of business practice.
A mutated FastSLAM using soft computing
Authors: Havangi Ramazan
Published: May 2017

Purpose

Simultaneous localization and mapping (SLAM) is the problem of determining the pose (position and orientation) of an autonomous robot moving through an unknown environment. The classical FastSLAM is a well-known solution to SLAM. In FastSLAM, a particle filter is used for the robot pose estimation, and the Kalman filter (KF) is used for the feature location’s estimation. However, the performance of the conventional FastSLAM is inconsistent. To tackle this problem, this study aims to propose a mutated FastSLAM (MFastSLAM) using soft computing.

Design/methodology/approach

The proposed method uses soft computing. In this approach, particle swarm optimization (PSO) estimator is used for the robot’s pose estimation and an adaptive neuro-fuzzy unscented Kalman filter (ANFUKF) is used for the feature location’s estimation. In ANFUKF, a neuro-fuzzy inference system (ANFIS) supervises the performance of the unscented Kalman filter (UKF) with the aim of reducing the mismatch between the theoretical and actual covariance of the residual sequences to get better consistency.

Findings

The simulation and experimental results indicate that the consistency and estimated accuracy of the proposed algorithm are superior FastSLAM.

Originality/value

The main contribution of this paper is the introduction of MFastSLAM to solve the problems of FastSLAM.
Exact laser beam positioning for measurement of vegetation vitality
Authors: Lindner Lars , Sergiyenko Oleg , Rivas-López Moises , Hernández-Balbuena Daniel , Flores-Fuentes Wendy , Rodríguez-Quiñonez Julio C. , Murrieta-Rico Fabian N. , Ivanov Mykhailo , Tyrsa Vera , Básaca-Preciado Luis C.
Published: May 2017

Purpose

The purpose of this paper is to present a novel application for a newly developed Technical Vision System (TVS), which uses a laser scanner and dynamic triangulation, to determine the vitality of agriculture vegetation. This vision system, installed on an unmanned aerial vehicle, shall measure the reflected laser energy and thereby determine the normalized differenced vegetation index.

Design/methodology/approach

The newly developed TVS shall be installed on the front part of the unmanned aerial vehicle, to perform line-by-line scan in the vision system field-of-view. The TVS uses high-quality DC motors, instead of previously researched low-quality DC motors, to eliminate the existence of two mutually exclusive conditions, for exact positioning of a DC motor shaft. The use of high-quality DC motors reduces the positioning error after control.

Findings

Present paper emphasizes the exact laser beam positioning in the field-of-view of a TVS. By use of high-quality instead of low-quality DC motors, a significant reduced positioning time was achieved, maintaining the relative angular position error less than 1 per cent. Best results were achieved, by realizing a quasi-continuous control, using a high pulse-width modulated duty cycle resolution and a high execution frequency of the positioning algorithm.

Originality/value

The originality of present paper is represented by the novel application of the newly developed TVS in the field of agriculture. The vitality of vegetation shall be determined by measuring the reflected laser energy of a scanned agriculture zone. The paper’s main focus is on the exact laser beam positioning within the TVS field-of-view, using high-quality DC motors in closed-loop position control configuration.