bluuebunny/crossref_metadata_2025 huggingface dataset:
Prognostic Value of The Lactate/Albumin Ratio for Predicting 28-Day Mortality in Critically ILL Sepsis Patients
Authors: Shin Jikyoung , Hwang Sung Yeon , Jo Ik Joon , Kim Won Young , Ryoo Seung Mok , Kang Gu Hyun , Kim Kyuseok , Jo You Hwan , Chung Sung Phil , Joo Young Seon , Beom Jin Ho , Yoon Young Hoon , Han Kap Su , Lim Tae Ho , Choi Han Sung , Kwon Woon Yong , Suh Gil Joon , Choi Sung-Hyuk , Shin Tae Gun
Published: February 2018

Aim:

The aim of this study was to evaluate the clinical utility of the lactate/albumin (L/A) ratio as a predictive factor of 28-day mortality in critically ill sepsis patients.

Methods:

This is a retrospective observational study from a prospectively collected multicenter registry of 10 emergency departments (EDs) in teaching hospitals that participated in the Korean Shock Society. It enrolled patients who were 19 years of age or older who had a suspected or confirmed infection and evidence of refractory hypotension or hypoperfusion. The prognostic performance of the L/A ratio and lactate level for predicting 28-day mortality was assessed. Lactate and albumin levels were measured immediately after ED arrival.

Results:

A total of 946 patients were included, with 22.5% overall 28-day mortality. The area under the receiver operating characteristic curve (AUROC) value of the L/A ratio (0.69, 95% confidence interval [CI] 0.64–0.73, P < 0.01) was higher than that of lactate (0.65, 95% CI 0.61–0.70, P < 0.01) for predicting 28-day mortality. The optimal cutoff of the L/A ratio was 1.32. The AUROC value of the L/A ratio was better than that of lactate regardless of lactate level (normal [<2.0 mmol/L]: 0.68 vs. 0.55; intermediate [≥2.0, < 4.0 mmol/L]: 0.65 vs. 0.50; high [≥4.0 mmol/L]: 0.66 vs. 0.62). In the subgroup with decreased lactate elimination, the AUROC value of the L/A ratio was also significantly higher than that of lactate (hepatic dysfunction: 0.70 vs. 0.66; renal dysfunction: 0.71 vs. 0.67). The L/A ratio cut-off and hypoalbminemia showed further discriminative value for 28-day mortality even in patients with normal or intermediate lactate levels.

Conclusions:

The prognostic performance of the L/A ratio was superior to that of a single lactate measurement for predicting 28-day mortality of critically ill sepsis patients. L/A ratio can be a useful prognostic factor regardless of initial lactate level and the presence of hepatic or renal dysfunction.
Metabarcoding lake sediments: taphonomy and representation of contemporary vegetation in environmental DNA (eDNA) records
Authors: Alsos Inger Greve , Lammers Youri , Yoccoz Nigel Giles , Jørgensen Tina , Sjögren Per , Gielly Ludovic , Edwards Mary E.
Published: February 2018

Metabarcoding of lake sediments may reveal current and past biodiversity, but little is known about the degree to which taxa growing in the vegetation are represented in environmental DNA (eDNA) records. We analysed composition of lake and catchment vegetation and vascular plant eDNA at 11 lakes in northern Norway. Out of 489 records of taxa growing within 2 m from the lake shore, 17-49% (mean 31%) of the identifiable taxa recorded were detected with eDNA. Of the 217 eDNA records, 73% and 12% matched taxa recorded in vegetation surveys within 2 m and up to about 50 m away from the lakeshore, respectively, whereas 16% were not recorded in the vegetation surveys of the same lake. The latter include taxa likely overlooked in the vegetation surveys or growing outside the survey area. The percentages detected were 61, 47, 25, and 15 for dominant, common, scattered, and rare taxa, respectively. Similar numbers for aquatic plants were 88, 88, 33 and 62%, respectively. Detection rate and taxonomic resolution varied among plant families and functional groups with good detection of e.g. Ericaceae, Roseaceae, deciduous trees, ferns, club mosses and aquatics. The representation of terrestrial taxa in eDNA depends on both their distance from the sampling site and their abundance and is sufficient for recording vegetation types. For aquatic vegetation, eDNA may be comparable with, or even superior to, in-lake vegetation surveys and therefore be used as an tool for biomonitoring. For reconstruction of terrestrial vegetation, technical improvements and more intensive sampling is needed to detect a higher proportion of rare taxa although DNA of some taxa may never reach the lake sediments due to taphonomical constrains. Nevertheless, eDNA performs similar to conventional methods of pollen and macrofossil analyses and may therefore be an important tool for reconstruction of past vegetation.
The intestinal microbiota predisposes to traveller’s diarrhoea and to the carriage of multidrug-resistant Enterobacteriaceae after travelling to tropical regions
Authors: Leo Stefano , Lazarevic Vladimir , Gaïa Nadia , Estellat Candice , Girard Myriam , Matheron Sophie , Armand-Lefèvre Laurence , Andremont Antoine ,   The VOYAG-R Study Group, Andremont Antoine , Armand-Lefèvre Laurence , Bouchaud Olivier , Boussadia Yacine , Campa Pauline , Coignard Bruno , Consigny Paul-Henri , Mniai Assiya El , Esposito-Farèse Marina , Estellat Candice , Girard Pierre-Marie , Goujon Catherine , Hoffmann Isabelle , Le Loup Guillaume , Lucet Jean-Christophe , Matheron Sophie , Moussa Nabila , Perrier Marion , Pialoux Gilles , Ralaimazava Pascal , Ruppè Etienne , Vittecoq Daniel , Wieder Ingrid , Wyplosz Benjamin , Schrenzel Jacques , Ruppé Etienne
Published: February 2018

The risk of acquisition of multidrug-resistant Enterobacteriaceae (MRE) and of occurrence of diarrhoea is high when travelling to tropical regions. The relationships between these phenomena and the composition of human gut microbiota have not yet been assessed. Here, we investigated the dynamics of changes of metabolically active microbiota by sequencing total RNA from faecal samples taken before and after travel to tropical regions. We found that the occurrence of diarrhoea during the travel was associated with a higher relative abundance of Prevotella copri before departure and after return. The composition of microbiota, before travel as well as at return, was not correlated with the acquisition of MRE. However, the clearance of MRE one month after return was linked to a specific pattern of bacterial species that was also found before and after return.
Population coupling predicts the plasticity of stimulus responses in cortical circuits
Authors: Sweeney Yann , Clopath Claudia
Published: February 2018

Long-term imaging of sensory cortex reveals a diverse range of stimulus response stability: some neurons retain stimulus responses that are stable over days whereas other neurons have highly plastic stimulus responses. Using a recurrent network model, we explore whether this observation could be due to an underlying diversity in the synaptic plasticity of neurons. We find that, in a network with diverse learning rates, neurons with fast rates are more coupled to population activity than neurons with slow rates. This phenomenon, which we call a plasticity-coupling link, surprisingly predicts that neurons with high population coupling exhibit more long-term stimulus response variability than neurons with low population coupling. We substantiate this prediction using recordings from the Allen Brain Observatory which track the orientation preferences of 15,000 neurons in mouse visual cortex. In agreement with our model, a neuron’s population coupling is correlated with the plasticity of its orientation preference. Finally, we show that high population coupling helps plastic neurons alter their stimulus preference during a simple perceptual learning task, but hinders the ability of stable neurons to provide an instructive signal for learning. This suggests a particular functional architecture: a stable ‘backbone’ of stimulus representation formed by neurons with slow synaptic plasticity and low population coupling, on top of which lies a flexible substrate of neurons with fast synaptic plasticity and high population coupling.
SV-plaudit: A cloud-based framework for manually curating thousands of structural variants
Authors: Belyeu Jonathan R. , Nicholas Thomas J. , Pedersen Brent S. , Sasani Thomas A. , Havrilla James M. , Kravitz Stephanie N. , Conway Megan E. , Lohman Brian K. , Quinlan Aaron R. , Layer Ryan M.
Published: February 2018

SV-plaudit is a framework for rapidly curating structural variant (SVs) predictions. For each SV, we generate an image that visualizes the coverage and alignment signals from a set of samples. Images are uploaded to our cloud framework where users assess the quality of each image using a client-side web application. Reports can then be generated as a tab-delimited file or annotated VCF. As a proof of principle, nine researchers collaborated for one hour to evaluate 1,350 SVs each. We anticipate that SV-plaudit will become a standard step in variant calling pipelines and the crowd-sourced curation of other biological results.

Code available at https://github.com/jbelyeu/SV-plaudit

Demonstration video available at https://www.youtube.com/watch?v=ono8kHMKxDs
End-to-end differentiable learning of protein structure
Authors: AlQuraishi Mohammed
Published: February 2018

Predicting protein structure from sequence is a central challenge of biochemistry. Co‐evolution methods show promise, but an explicit sequence‐to‐structure map remains elusive. Advances in deep learning that replace complex, human‐designed pipelines with differentiable models optimized end‐to‐end suggest the potential benefits of similarly reformulating structure prediction. Here we report the first end‐to‐end differentiable model of protein structure. The model couples local and global protein structure via geometric units that optimize global geometry without violating local covalent chemistry. We test our model using two challenging tasks: predicting novel folds without co‐evolutionary data and predicting known folds without structural templates. In the first task the model achieves state‐of‐the‐art accuracy and in the second it comes within 1‐2Å; competing methods using co‐evolution and experimental templates have been refined over many years and it is likely that the differentiable approach has substantial room for further improvement, with applications ranging from drug discovery to protein design.
Homogenization of species composition and species association networks are decoupled
Authors: Li Daijiang , Poisot Timothée , Waller Donald , Baiser Benjamin
Published: February 2018

Ecological communities are comprised of both species and the biotic relationships among them. Biotic homogenization in species composition (i.e. increased site-to-site similarity) is recognized a common consequence of global change, but less is known about how species relationships change over space and time. Does homogenization of species composition lead to homogenization of species relationships or are the dynamics of species relationships decoupled from changes in species composition? To answer this question, we used long-term resurvey data to analyze changes in plant species association patterns between the 1950s and 2000s at 266 sites distributed among three community types in Wisconsin, USA. We used species associations (quantified via local co-occurrence patterns) as a proxy for species relationships. Species pairs that co-occur more/less than expected by chance have positive/negative associations. Shifts in species associations consistently exceeded the shifts observed in species composition. Less disturbed forests of northern Wisconsin have converged somewhat in species composition but not much in species associations. In contrast, forests in central Wisconsin succeeding from pine barrens to closed-canopy forests have strongly homogenized in both species composition and species associations. More fragmented forests in southern Wisconsin also tended to converge in species composition and in the species negative associations, but their positive associations diverged over the last half century. We conclude that long-term shifts in species relationships may be decoupled from those of species composition despite being affected by similar environmental variables.
Measurements of the Self-Assembly Kinetics of Individual Viral Capsids Around Their RNA Genome
Authors: Garmann Rees F. , Goldfain Aaron M. , Manoharan Vinothan N.
Published: February 2018

The formation of a viral capsid-the highly—ordered protein shell that surrounds the genome of a virus—is the canonical example of self-assembly1. The capsids of many positive-sense RNA viruses spontaneously assemble from in vitro mixtures of the coat protein and RNA2. The high yield of proper capsids that assemble is remarkable, given their structural complexity: 180 identical proteins must arrange into three distinct local configurations to form an icosahedral capsid with a triangulation number of 3 (T = 3)1. Despite a wealth of data from structural studies3–5 and simulations6–10, even the most fundamental questions about how these structures assemble remain unresolved. Experiments have not determined whether the assembly pathway involves aggregation or nucleation, or how the RNA controls the process. Here we use interferometric scattering microscopy11,12 to directly observe the in vitro assembly kinetics of individual, unlabeled capsids of bacteriophage MS2. By measuring how many coat proteins bind to each of many individual MS2 RNA strands on time scales from 1 ms to 900 s, we find that the start of assembly is broadly distributed in time and is followed by a rapid increase in the number of bound proteins. These measurements provide strong evidence for a nucleation-and-growth pathway. We also find that malformed structures assemble when multiple nuclei appear on the same RNA before the first nucleus has finished growing. Our measurements reveal the complex assembly pathways for viral capsids around RNA in quantitative detail, including the nucleation threshold, nucleation time, growth time, and constraints on the critical nucleus size. These results may inform strategies for engineering synthetic capsids13 or for derailing the assembly of pathogenic viruses14.
Protein Kinase A Negatively Regulates Ca2+ signaling in Toxoplasma gondii
Authors: Uboldi Alessandro D. , Wilde Mary-Louise , McRae Emi A. , Stewart Rebecca J. , Dagley Laura F. , Yang Luning , Katris Nicholas J , Hapuarachchi Sanduni V. , Coffey Michael J , Lehane Adele M. , Botte Cyrille Y , Waller Ross F. , Webb Andrew I. , Tonkin Christopher J.
Published: February 2018

The phylum Apicomplexa comprises a group of obligate intracellular parasites that alternate between intracellular replicating forms and actively motile extracellular forms that move through tissue. Parasite cytosolic Ca2+ signalling activates motility, but how this is switched off after invasion is not understood. Here we show that the cAMP-dependent Protein Kinase A catalytic subunit 1 (PKAc1) of Toxoplasma is responsible for suppression of Ca2+ signalling upon host cell invasion. We demonstrate that that PKAc1 is sequestered to the parasite periphery by dual acylation of its regulatory subunit PKAr1. Newly invaded PKAc1-deficient parasites exit host cells shortly thereafter in a perforin-like protein 1 (PLP-1)-dependent fashion. We demonstrate that loss of PKAc1 results in an inability to rapidly downregulate cytosolic Ca2+ levels shortly after invasion. Furthermore, we demonstrate that PKAc1 also specifically negatively regulates resting cytosolic Ca2+ in conditions that mimic intracellularity. We also show that cAMP and cGMP have opposing role in microneme secretion, further supporting evidence that cAMP signalling has a suppressive role during motility. Together, this work provides a new paradigm in understanding how Toxoplasma and related apicomplexan parasites regulate infectivity.
RD5-mediated lack of PE_PGRS and PPE-MPTR export in BCG vaccine strains results in strong reduction of antigenic repertoire but little impact on protection
Authors: Ates Louis S. , Sayes Fadel , Frigui Wafa , Ummels Roy , Damen Merel P. M. , Bottai Daria , Behr Marcel A. , Bitter Wilbert , Majlessi Laleh , Brosch Roland
Published: February 2018

Tuberculosis is the deadliest infectious disease worldwide. Although the BCG vaccine is widely used, it does not efficiently protect against pulmonary tuberculosis and an improved tuberculosis vaccine is therefore urgently needed.Mycobacterium tuberculosisuses different ESX/Type VII secretion (T7S) systems to transport proteins important for virulence and host immune responses. We recently reported that secretion of T7S substrates belonging to the mycobacteria-specific Pro-Glu (PE) and Pro-Pro-Glu (PPE) proteins of the PGRS (polymorphic GC-rich sequences) and MPTR (major polymorphic tandem repeat) subfamilies required both a functional ESX-5 system and a functional PPE38/71 protein for secretion. Inactivation ofppe38/71and the resulting loss of PE_PGRS/PPE-MPTR secretion were linked to increased virulence ofM. tuberculosisstrains. Here, we show that a predicted total of 89 PE_PGRS/PPE-MPTR surface proteins are not exported by certain animal-adapted strains of theM. tuberculosiscomplex includingM. bovis.This Δppe38/71-associated secretion defect therefore also occurs in theM. bovis-derived tuberculosis vaccine BCG and could be restored by introduction of theM. tuberculosisppe38-locus. Epitope mapping of the PPE-MPTR protein PPE10, further allowed us to monitor T-cell responses in splenocytes from BCG/M.tuberculosisimmunized mice, confirming the dependence of PPE10-specific immune-induction on ESX-5/PPE38-mediated secretion. Restoration of PE_PGRS/PPE-MPTR secretion in recombinant BCG neither altered global antigenic presentation or activation of innate immune cells, nor protective efficacy in two different mouse vaccination-infection models. This unexpected finding stimulates a reassessment of the immunomodulatory properties of PE_PGRS/PPE-MPTR proteins, some of which are contained in vaccine formulations currently in clinical evaluation.
Real-time in vivo Global Transcriptional Dynamics During Plasmodium falciparum Blood-stage Development
Authors: Painter Heather J. , Chung Neo Christopher , Sebastian Aswathy , Albert Istvan , Storey John D. , Llinás Manuel
Published: February 2018

Genome-wide analysis of transcription in the human malaria parasite Plasmodium falciparum has revealed robust variation in steady-state mRNA abundance throughout the 48-hour intraerythrocytic developmental cycle (IDC) suggesting that this process is highly dynamic and tightly regulated. However, the precise timing of mRNA transcription and decay remains poorly understood due to the utilization of methods that only measure total RNA and cannot differentiate between newly transcribed, decaying and stable cellular RNAs. Here we utilize rapid 4-thiouracil (4-TU) incorporation via pyrimidine salvage to specifically label, capture and quantify newly-synthesized P. falciparum RNA transcripts at every hour throughout the IDC following erythrocyte invasion. This high resolution global analysis of the transcriptome captures the timing and rate of transcription for each newly synthesized mRNA in vivo, revealing active transcription throughout all stages of the IDC. To determine the fraction of active transcription and/or transcript stabilization contributing to the total mRNA abundance at each timepoint we have generated a statistical model to fit the data for each gene which reveals varying degrees of transcription and stabilization for each mRNA corresponding to developmental transitions and independent of abundance profile. Finally, our results provide new insight into co-regulation of mRNAs throughout the IDC through regulatory DNA sequence motifs associated with these processes, thereby expanding our understanding of P. falciparum mRNA dynamics.
Electron-density critical points analysis and catastrophe theory to forecast structure instability in periodic solids
Authors: Merli Marcello , Pavese Alessandro
Published: February 2018

The critical points analysis of electron density,i.e. ρ(x), fromab initiocalculations is used in combination with the catastrophe theory to show a correlation between ρ(x) topology and the appearance of instability that may lead to transformations of crystal structures, as a function of pressure/temperature. In particular, this study focuses on the evolution of coalescing non-degenerate critical points,i.e. such that ∇ρ(xc) = 0 and λ1, λ2, λ3≠ 0 [λ being the eigenvalues of the Hessian of ρ(x) atxc], towards degenerate critical points,i.e. ∇ρ(xc) = 0 and at least one λ equal to zero. The catastrophe theory formalism provides a mathematical tool to model ρ(x) in the neighbourhood ofxcand allows one to rationalize the occurrence of instability in terms of electron-density topology and Gibbs energy. The phase/state transitions that TiO2(rutile structure), MgO (periclase structure) and Al2O3(corundum structure) undergo because of pressure and/or temperature are here discussed. An agreement of 3–5% is observed between the theoretical model and experimental pressure/temperature of transformation.
Coordination numbers of the vertex graph of a Penrose tiling
Authors: Shutov Anton , Maleev Andrey
Published: February 2018

A new approach to study coordination shells and coordination sequences of quasiperiodic graphs is suggested. The structure of the coordination shells in the vertex graph of a Penrose tiling is described. An asymptotic formula for its coordination numbers is obtained. An essentially different behaviour of the coordination numbers for even and odd shells is revealed.
A new approach in animal diet using grey system theory
Authors: Salookolaei Davood Darvishi , Liu Sifeng , Nasseri Sayed Hadi
Published: February 2018

Purpose

The purpose of this paper is to discuss the animal diet problem in grey environment which is adapted to the real situations. In particular, a new approach to solve these problems is proposed.

Design/methodology/approach

With the objective to produce the least-cost diet, in the traditional model for optimizing the diet problem, the price of foods, the nutrients requirements and the necessity of foods requirement have been considered as grey interval numbers. Grey linear programming approach has been employed to solve the grey diet problem. Grey linear programming with flexibility in selection of the coefficients can be more effective for solving the diet problems. In this research, only the positioned method has been used. The grey diet model is solved by using GAMS software based on the positioned method.

Findings

The main contribution of this work is to introduce a new model in the practical case that is concerned with diet problem under a kind of uncertainty environment and furthermore, proposing a novel method to solve the formulated problem. In this way, using a grey model and applying all restrictions, the least cost for one kilogram of total mixed ration was 6,893-10,163 Rials, and at this level, cow’s nutrient requirement was met. Based on the numerical examination, which was done on the real case, the achieved results have showed that the uncertainty of foods requirement and nutrients requirements had slight effect on the animal budget diet.

Originality/value

This problem must be viewed from another perspective because of the uncertainty regarding the amount of nutrients per unit of foods and the diversity of animals’ daily needs to receive them. In particular, a new method to optimize the fully mixed diet of lactating cows in early lactation that are readily available in the northeast of Iran in uncertainty environment has been proposed.
New axiomatic approach to the concept of grey information
Authors: Mierzwiak Rafal , Xie Naiming , Nowak Marcin
Published: February 2018

Purpose

Considering current development of Grey Systems Theory (GST), we can come up with the following thesis: practical applications are a dominant subject of research. Thus, what seems to be symptomatic for relatively young knowledge disciplines, the authors observe the presence of imbalance between the development of GST application tools and theory’s epistemological and methodological background. As for GST, epistemological and methodological problems are becoming visible especially in the issues of determining a clear criterion of demarcation of this kind of a theory from others. In other words, this problem can be reduced to the issue of a precise determination of what the category of a grey system and grey information is. This problem is of great importance for further development and popularisation of GST in the world of science. Realising its significance, the purpose of this paper is to create a general overview of Grey Systems epistemology and afterwards create axiomatic and formal frames for a category of greyness.

Design/methodology/approach

In order to achieve set goals, two research approaches were accepted. In the area of inference about epistemology of GST an approach characteristic of an analytical philosophy was used, whereas in the case of axiomatic and formal frames for a category of greyness the authors referred to terms of a set theory and the principles of a pragmatic logic.

Findings

The result of research is to formulate a concept of a grey system and a concept of grey information in the context of a process of cognition. Moreover, a function of greyness and other fundamental categories of GST will be defined in an axiomatic way.

Originality/value

The paper presents a new consistent frame for the issues of methodological and epistemological backgrounds of GST. An original concept is to refer in considerations to a newly proposed grey space. This space was used for a formal justification of such elementary categories as grey numbers, a weight function of whitenization or grey sequences. The value of achievements shown in the paper is underlined by the fact that proposed theoretical constructions require further development and they can potentially open up new research trends in the GST.
Maximum entropy methods for weighted grey incidence analysis and applications
Authors: Quan Jing , Zeng Bo , Wang LuYun
Published: February 2018

Purpose

Equally weighted factors and initial data from behavioural sequences are used for calculating the degree of grey incidence in Deng’s grey incidence analysis. However, certain grey information cannot be directly obtained, and the correlation coefficients of each sequence at different times are of different importance to the system. The purpose of this paper is to propose an improved grey incidence model with new grey incidence coefficients and weighted degree of grey incidence. Some grey information can be obtained more easily by using the grey transformation sequences, and the maximum entropy method is used to calculate the weights of new grey incidence coefficients, so the new degree of grey incidence was distinguished more effectively by the proposed model.

Design/methodology/approach

New grey incidence coefficients are defined using transformation sequences of the initial data. To overcome the shortcomings arising from the use of equal weights, the maximum entropy method is proposed for determining the weights of the grey incidence coefficients. The resulting model optimises the classical models and evaluates the influencing factors more effectively. The effectiveness of the model was verified by a numerical example. Furthermore, the model was used for analysing the main influencing factors of the tertiary industry in China.

Findings

The proposed model optimises the classical models, and the application example shows that urbanisation has the greatest effect on employment in the tertiary sector.

Originality/value

An improved grey incidence model is proposed that improves the grey incidence coefficients and their weights, and has better performance than the classical models. The model was successfully used in the analysis of the influence factors of the tertiary industry in China. The results indicate that the model can reflect the significance of incidence coefficients at different time points; therefore, their fluctuation can be effectively controlled.
Middle-range theorizing on logistics customer service
Authors: Pellathy Daniel A. , In Joonhwan , Mollenkopf Diane A. , Stank Theodore P.
Published: February 2018

Purpose

The purpose of this paper is to illustrate how a systematic application of middle-range theorizing, which pays particular attention to contexts and mechanisms, can be used to extend current knowledge on logistics customer service (LCS) in a number of critical areas.

Design/methodology/approach

The paper applies Stanket al.’s (2017) framework for middle-ranging theorizing in logistics to develop a research framework and agenda that can guide future LCS research. Results are generated through a review of the LCS literature and an application of the main concepts of middle-range theorizing.

Findings

The paper outlines opportunities for middle-range research that would extend LCS knowledge in the areas of human and behavioral factors, time-based competition, supply chain complexity, and digitization and technological innovation.

Research limitations/implications

Describing the main characteristics of middle-range theorizing and how middle-range theorizing can be fruitfully applied to LCS research should help to stimulate new knowledge creation in this important area of supply chain logistics management.

Practical implications

By focusing on why and when questions, middle-range theorizing engages with the practical realities of LCS that interest managers and students. Middle-range theorizing moves researchers toward developing a detailed understanding of what actually has to change in order for desired LCS-related outcomes to occur and the contextual factors likely impacting the change process. The paper should, therefore, allow managers to better translate LCS theory into action.

Originality/value

Middle-range theorizing remains new to the supply chain logistics field. The application of middle-range theorizing to LCS research, and logistics research more generally, demands new perspectives on established relationships with the potential to drive original research in areas most relevant to managers.
Modeling median will-cost estimates for defense acquisition programs
Authors: Trudelle Ryan , White Edward D. , Ritschel Dan , Koschnick Clay , Lucas Brandon
Published: February 2018

Purpose

The introduction of “should cost” in 2011 required all Major Defense Acquisition Programs (MDAP) to create efficiencies and improvements to reduce a program’s “will-cost” estimate. Realistic “will-cost” estimates are a necessary condition for the “should cost” analysis to be effectively implemented. Owing to the inherent difficulties in establishing a program’s will-cost estimate, this paper aims to propose a new model to infuse realism into this estimate.

Design/methodology/approach

Using historical data from 73 Departments of Defense programs as recorded in the selected acquisition reports (SARs), the analysis uses mixed stepwise regression to predict a program’s cost from Milestone B (MS B) to initial operational capability (IOC).

Findings

The presented model explains 83 per cent of the variation in the program acquisition cost. Significant predictor variables include: projected duration (months from MS B to IOC); the amount of research development test and evaluation (RDT&E) funding spent at the start of MS B; whether the program is considered a fixed-wing aircraft; whether a program is considered an electronic system program; whether a program is considered ACAT I at MS B; and the program size relative to the total program’s projected acquisition costs at MS B.

Originality/value

The model supports the “will-cost and should-cost” requirement levied in 2011 by providing an objective and defensible cost for what a program should actually cost based on what has been achieved in the past. A quality will-cost estimate provides a starting point for program managers to examine processes and find efficiencies that lead to reduced program costs.
Analysis of performance on a modified Wisconsin Card Sorting Test for the military
Authors: Moten Cardy , Kennedy Quinn , Alt Jonathan , Nesbitt Peter
Published: February 2018

Purpose

Current Army doctrine stresses a need for military leaders to have the capability to make flexible and adaptive decisions based on a future unknown environment, location and enemy. To assess a military decision maker’s ability in this context, this paper aims to modify the Wisconsin Card Sorting Test which assesses cognitive flexibility, into a military relevant map task. Thirty-four military officers from all service branches completed the map task.

Design/methodology/approach

The purpose of this study was to modify a current psychological task that measures cognitive flexibility into a military relevant task that includes the challenge of overcoming experiential bias, and understand underlying causes of individual variability in the decision-making and cognitive flexibility behavior of active duty military officers on this task.

Findings

Results indicated that non-perseverative errors were a strong predictor of cognitive flexibility performance on the map task. Decomposition of non-perseverative error into efficient errors and random errors revealed that participants who did not complete the map task changed their sorting strategy too soon within a series, resulting in a high quantity of random errors.

Originality/value

This study serves as the first step in customizing cognitive psychological tests for a military purpose and understanding why some military participants show poor cognitive flexibility.
Drivers of value management in the Nigerian construction industry
Authors: Oke Ayodeji Emmanuel , Aghimien Douglas Omoregie
Published: February 2018

Purpose

The paper aims to determine the possible drivers of value management (VM) in the construction industry with a view of providing better-quality construction and achieving value for money through its usage.

Design/methodology/approach

The study adopts a survey design, and construction professionals from various strata in the six geopolitical zones in Nigeria are assessed using a convenience sample through the use of a structured questionnaire. Frequency, percentage, mean score and one-sample t-test are used for analysing the data gathered.

Findings

Result revealed that although knowledge regarding VM practices is high, its adoption in the industry is average and the involvement of construction professionals in VM workshops is low. Government involvement through the introduction of VM policy, client commitment and proper understanding of VM methodology aid the adoption of VM practices.

Practical implications

This research was conducted across six geopolitical zones of the country as against common practice of selecting a particular region or state to represent the entire country. The findings therefore show a true reflection of the VM drivers in the country. Its recommendations can, to a large extent, increase the use of VM in the country and also other developing countries where construction projects are executed through a similar method, style and approach.

Originality/value

This paper highlights the possible ways of increasing the use of VM in the construction industry with a view to achieve better-quality construction and value for money.
Analysis of runway pavement response under aircraft moving load by FEM
Authors: Shafabakhsh Gholamali , Kashi Ehsan , Tahani Mojtaba
Published: February 2018

Purpose

Given the importance of airports and the need to develop this issue in runway, the purpose of this study, pavement response values under loading of different aircraft have been obtained using tire and pavement modeling by finite element method (FEM). To predict the actual behavior of pavements under aircraft loading, dynamic analysis of runway flexible pavement was performed using Abaqus software version 6.10.

Design/methodology/approach

The method is based on finite element analysis and software simulation. And the main goal to obtain the amount of pavement stress and deflection at different speeds.

Findings

The results of modeling showed that aircraft movement at a speed of 5-8 km/h leads to the highest stresses and deflections in the pavement. Moreover, the effect of elastic modulus variations of the asphalt concrete on the tensile strain under advisory circular layer was calculated for Airbus A380 by using FEM. To validate the results of the runway pavement dynamic analysis, the results of modeling have been compared with the field test results of National Airport Pavement Test Facility.

Originality/value

Stresses and deflections of pavement during aircraft movement at different speeds of 5, 8 and 20 km/h on the runway have been presented, and the critical points in length, width and depth of runway pavement, as well as the most critical speed of aircraft in terms of induced damage to the pavement, have been obtained.
Monitoring joint quality: Taguchi approach and structure investigation
Authors: Reda Reham , Saad Mohamed , Ahmed Mohamed Zaky , Abd-Elkader Hoda
Published: February 2018

Purpose

This paper aims to monitor, evaluate and adjust the joint quality of dissimilar friction stir welded AA2024-T3 and AA7075-T6 Al alloys.

Design/methodology/approach

Taguchi analysis for design of experiments and ANOVA analysis were applied. Tensile test, visual inspection and macro and microstructure investigations were carried out at each welding condition. In addition, the grain size of stir zone and the value of heat input were measured.

Findings

Using Taguchi analysis, the optimum values of tool rotary speed, welding speed and axial load were 1,200 rpm, 100 mm/min and 1,300 kg, respectively, yielding the maximum tensile strength of the joints of 427 MPa. ANOVA analysis indicated that the most significant parameter on the joint strength is the tool rotary speed, followed by welding speed and axial load, with contributions of 67, 27 and 2 per cent, respectively. Best mixing between Al alloys in the stir zone with no defects was observed at moderate speeds because of proper heat input and grain size, resulting in high strength.

Originality/value

A relation between structure characteristics of the joint, the process parameters and the joint strength was established to control the joint quality.
Emotional intelligence and transformational leadership behaviours of construction project managers
Authors: Potter Emily M. , Egbelakin Temitope , Phipps Robyn , Balaei Behrooz
Published: February 2018

Purpose

Existing research has highlighted the need for influential leaders to respond to the evolving social, economic and environmental constraints on the construction industry. Studies on leadership in other sectors have shown that influential leaders tend to demonstrate a high level of emotional intelligence. Little or no research examining relationships between leadership style and emotional intelligence has been conducted specific to construction project managers. This study aims to identify the prevalent leadership style adopted by construction project managers and investigate potential correlations between leadership style and emotional intelligence.

Design/methodology/approach

An online questionnaire including a mix of open and closed questions was adopted to address the research objectives. The group studied comprised project managers currently working in the construction industry in New Zealand and the UK.

Findings

The research found that transformational leadership style is prevalent among project managers examined in this study. Significant positive relationships were found between project managers’ emotional intelligence and their likelihood of adopting a transformational leadership style.

Originality/value

The research results provide the construction industry with a benchmark against which individuals with high emotional intelligence, and so most suited to the challenges of the project management role, can be identified and trained. Recommendations including suitable methods for identifying, recruiting and training project managers, as well as secondment and mentoring options, were suggested for improving leadership capabilities in the construction industry.
Quality of work life of Emirati women and its influence on job satisfaction and turnover intention
Authors: Jabeen Fauzia , Friesen Heather Lynn , Ghoudi Kilani
Published: February 2018

Purpose

The purpose of the paper is to examine the quality of work life (QoWL) and its influence on job satisfaction and turnover (job-leaving) intention of Emirati women employed in various public sector organizations in the United Arab Emirates (UAE).

Design/methodology/approach

Data were collected through a structured questionnaire gleaned from literature, and were analyzed through partial least squares structural equation modeling.

Findings

QoWL was found to have a significant relationship with all variables in the model, and was found, as hypothesized, to have a positive effect on job satisfaction and a negative effect on turnover intention.

Research limitations/implications

One of the main limitations of this study is that the sample is drawn from only Emirati female employees who were working in public organizations based in the Abu Dhabi region, the capital of UAE, and hence, cannot be generalized.

Practical implications

This study helps policy makers by identifying crucial points that can improve Emirati female employees’ QoWL with a commensurate reduction in turnover intention in a collectivistic society. Public sector organizations should address the factors that directly affect Emirati women’s QoWL and job satisfaction, as it will ultimately result in less staff turnover, greater productivity, and will also support the localization strategy.

Originality/value

The study is one of the first enquiries which stresses the importance of understanding how Emirati female employees perceive and categorize themselves as a valuable element of the workplace alongside the significance of augmenting their sense of belongingness to their organization.
Organizational network and strategic business performance
Authors: Yousaf Zahid , Majid Abdul
Published: February 2018

Purpose

The purpose of this paper is to address the key issues, how organizational networks influence the strategic business performance (SBP) through the mediating role of organizational flexibility, and the moderating role of entrepreneurial orientation (EO). Contextualizing small and medium enterprises in developing countries, the authors have developed and tested a theoretical model of SBP to provide a framework for analyzing its major antecedents.

Design/methodology/approach

This research used a quantitative approach with cross-sectional data. The authors used correlation, regression and Baron and Kenny Approach (Causal Step Approach) for analyzing the data collected from 737 CEOs/MDs/owners of different small and medium enterprises to test the theoretical model developed for this study.

Findings

Findings revealed that organizational flexibility mediates the relationship between organizational network and SBP. Furthermore, stronger EO strengthens the relationship between organizational flexibility and SBP.

Originality/value

This study contributes in two ways: first, it provides empirical evidences that how to flourish the mechanism of SBP in SMEs. Second, this work contributes to understand the effects of organizational networks, flexibility and EO on SBP.
A 0.079 mm2 2.1-to-4.2 GHz ring-VCO employing programmable current topology
Authors: Awais Muhammad , Ramiah Harikrishnan , Lim Chee-Cheow , Chuah Joon Huang
Published: February 2018

Purpose

The purpose of this work in designing a wideband ring voltage-controlled oscillator (VCO) based on programmable current topology. It occupies a very tiny area yet achieving a good phase noise performance, which is suitable to be implemented in cost-effective and wideband frequency synthesizers.

Design/methodology/approach

The tuning range and gain are improved by dividing the VCO tuning curve into multiple curves controlled by programmable current sources without introducing additional parasitic capacitance.

Findings

Fabricated in 130-nm standard complementary metal oxide semiconductor technology and occupying an area of 0.079 mm2, the VCO is tunable from 2.05 to 4.19 GHz, with a tuning percentage of 68.5 per cent. The VCO measures a phase noise performance of −96.7 dBc/Hz at an offset of 1 MHz from a 4.19 GHz carrier while consuming an average current of 6.5 mA, achieving figure of merit (FoM) and FoMT of −158.9 and −175.6 dBc/Hz, respectively.

Originality/value

The proposed design uses programmable current topology without introducing parasitic capacitance, hence achieving wideband operation. It also occupies a tiny area and achieves a good phase noise performance.
High power 3-bit GaN high-pass/low-pass phase shifter for X-band applications
Authors: Sun Pengpeng , Liu Hui , Geng Miao , Zhang Rong , Yuan Tingting , Luo Wei Jun
Published: February 2018

Purpose

The design and performance of X-band high power 3-bit phase shifter which has been fabricated in 0.25µm GaN HEMT technology are presented.

Design/methodology/approach

Each bit of this phase shifter design is based on high-pass/low-pass topology.

Findings

For all eight states, the insertion loss is 12.5 ± 2.5 dB from 8-10 GHz and the input return loss is better than 9 dB over 8-10 GHz. The 3-bit phase shifter achieves a RMS phase error of 1o at 8.5 GHz and a RMS amplitude error less than 1.1dB. The measured continuous wave power data demonstrates typical input RF power handing capability of 32 dBm at 8 GHz.

Originality/value

This is to the authors’ knowledge the first published results of 3-bit AlGaN/GaN phase shifter.
A process for estimating minimum feature size in selective laser sintering
Authors: Weiss Benjamin , Diegel Olaf , Storti Duane , Ganter Mark
Published: February 2018

Purpose

Manufacturer specifications for the resolution of an additive manufacturing (AM) machine can be ten times smaller (more optimistic) than the actual size of manufacturable features. Existing methods used to establish a manufacturable design rule-set are conservative piecewise-constant approximations. This paper aims to evaluate the effectiveness of a first-order model for producing improved design rule-sets for feature manufacturability, accounting for process variation.

Design/methodology/approach

A framework is presented which uses an interpolation method and a statistical model to estimate the minimum size for a wide range of features from a set of iterative experiments.

Findings

For an SLS process, using this approach improves the accuracy and reliability of minimum feature size estimates for a wider variety of features than assessed by most existing test artifacts.

Research limitations/implications

More research is needed to provide better interpolation models, broaden applicability and account for additional geometric and process parameters which significantly impact the results. This research focuses on manufacturability and does not address dimensional accuracy of the features produced.

Practical implications

An application to the design of thin channels in a prosthetic hand shows the utility of the results in a real-world scenario.

Originality/value

This study is among the first to investigate statistical variation of “pass/fail” features in AM process characterization, propose a means of estimating minimum feature sizes for shapes not directly tested and incorporate a more efficient iterative experimental protocol.