bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing infant and maternal readiness for newborn discharge
Authors: Jing Ling , Bethancourt Casidhe-Nicole , McDonagh Thomas
Published: July 2017

Purpose of review

The review highlights the shift from prescribed length of stay (LOS) to mother–infant dyad readiness as the basis for making discharge decisions for healthy term newborns. We describe the components of readiness that should be considered in making the decision, focusing on infant clinical readiness, and maternal and familial readiness.

Recent findings

Although the Newborns’ and Mothers’ Health Protection Act of 1996 aimed to protect infants and mothers by establishing a minimum LOS, the American Academy of Pediatrics 2015 policy on newborn discharge acknowledges the shift from LOS-based to readiness-based discharge decision-making. Healthcare providers must consider a variety of infant and maternal characteristics in determining the appropriate time to discharge a dyad, and mothers should be actively involved in the decision-making process. Criteria for infant clinical readiness include the following: establishment of effective feeding, evaluation of jaundice risk, review and discussion of infant and household vaccination status, obtainment of specimen for metabolic screening, tests of hearing ability, assessment of sepsis risk factors, screening for congenital heart disease, and evaluation of parental knowledge about infant safety measures. Important consideration should also be given to the mother's sociodemographic vulnerabilities, maternal confidence and perception of discharge readiness, and availability of postdischarge care continuity.

The timing of newborn discharge should be a joint decision made by the mother and healthcare providers based on readiness. The decision should consider the infant's health status, the mother's health status, the mother's perception of readiness, and the availability of social and familial support for the mother and infant. Accessible and comprehensive support postdischarge is also important for helping infants achieve optimal health outcomes.
A Case Presentation: Rare Occurrence of an Adolescent Male Presenting With an ATRT and Simultaneous Low-grade Glioneuronal Tumor
Authors: Cascio Matthew , Rivera-Zengotita Marie , Fort John
Published: July 2017

Atypical rhabdoid/teratoid tumor (ATRT) is an uncommon and highly malignant tumor of the central nervous system. The majority of ATRT tumors occur in infancy and young children located in the posterior fossa. The ideal treatment for cure remains controversial and prognosis is typically unfavorable. We present a case of an atypical presentation of ATRT, presenting in adolescence with an additional low-grade glioneuronal tumor discovered at diagnosis.
Seroprevalence of Chlamydia trachomatis in Inner-City Children and Adolescents—Implications for Vaccine Development
Authors: Banniettis Natalie , Thumu Sirisha , Weedon Jeremy , Chotikanatis Kobkul , Szigeti Aviva , Hammerschlag Margaret R. , Kohlhoff Stephan A.
Published: July 2017

Background

Prevention of Chlamydia trachomatis infection is an ideal application for a vaccine program, which should optimally be administered before sexual debut. However, there are limited epidemiologic studies of C. trachomatis infection in an unselected pediatric population since routine screening and treatment of pregnant women was implemented in the United States in 1993.

Methods

Anonymized serum samples were obtained from children younger than 21 years in 2 medical centers in Brooklyn, New York, from 2013 to 2015. Anti–C. trachomatis IgG antibody was determined by a validated enzyme immunoassay. Infants younger than 1 year were excluded from the final analysis due to interference of maternal antibody.

Results

One thousand two sera were included in the final analysis. Fifty-seven percent were females. No antibody was detected at younger than 11 years. Anti–C. trachomatis IgG antibody was detected in 11.4% and 5.6% of female and male subjects, respectively, older than 11 years (P = 0.0027), and seropositivity increased with age. There was no significant difference in the distribution of age at infection between the centers (P = 0.432), but a difference was detected between genders (P = 0.012) with a higher percentage of female subjects testing positive.

Conclusions

Antibody was first detected at 11 years of age, likely coinciding with sexual debut. The prevalence of antibody was higher and appeared earlier in females, mirroring national surveillance trends based on nucleic acid amplification testing. The delay in male antibody detection may be due to biological or behavioral differences between genders. These data are critical in informing potential C. trachomatis vaccine strategies.
A 5-Minute Interval between Two Dilating Eye Drops Increases Their Effect
Authors: Denion Eric , Charlot Frédérique , Béraud Guillaume
Published: July 2017

PURPOSE

Patients are usually advised to wait 5 minutes between eye drops. This delay supposedly allows the first drop not to be washed out by the second one, thereby increasing the combined effect. However, in the only experimental study conducted in humans on the concurrent administration of two different eye drops, the authors concluded that a 10-minute time interval between eye drops did not increase their combined effect. Our study was designed to address this puzzling observation.

METHODS

Using digital photographs shot in photopic conditions in 40 eyes of 20 healthy volunteers, we compared relative pupil surface (i.e., pupil to iris surface area ratios) before and after the administration of one drop of 10% phenylephrine and one drop of 0.5% tropicamide either immediately or after a 5-minute time interval.

RESULTS

Waiting 5 minutes yielded a 5.6% relative pupil surface gain (observer 1: P = .003, observer 2: P = .005) indicating an additional combined effect with a 5-minute time interval.

CONCLUSIONS

These results show a detectable additive effect that is probably the result of methodological refinements including the challenging of the mydriasis by photopic conditions and the use of pupil and iris surface areas, which may show differences that would be undetectable in terms of diameter.
Cancer Immunotherapy in Older Patients
Authors: Marrone Kristen A. , Forde Patrick M.
Published: July 2017

Advancing age remains one of the most significant risk factors for cancer development. Changes in the immune system occur with aging, and likely play a role in the increased incidence of malignancy in older patients. With the advent of immune checkpoint inhibitors, and their use in a variety of malignancies, there has been an explosion of clinical trials evaluating their use. Unfortunately, these trials have not shown consistent results in elderly patients, nor have age-specific outcomes been consistently reported. Further evaluation of the efficacy and toxicity of these agents in the elderly is needed, as they are now in frequent clinical use. By investigating how age-related changes in the immune system occur and intersect with use of immune checkpoint inhibitors, their use can be optimized in a clear and safe manner. Further study of age-related changes in the immune system can also lead to effective combination immunotherapeutic approaches, maximizing the efficacy of immune checkpoint inhibitors across tumor types and across the age spectrum of cancer patients.
The Biology of Aging and Cancer
Authors: Zhang Xinwen , Meng Xin , Chen Yiyin , Leng Sean X. , Zhang Haiyan
Published: July 2017

The majority of patients with common malignancies are older adults. Intrinsic complex biological changes of aging along with inflammation, immunosenescence, age-associated chronic diseases, and extrinsic environmental and psychosocial factors have significant impact on not only development and behavior of individual malignancies, but also physiologic reserve and vulnerability of older patients who suffer from them. As a result, clinical practice of geriatric oncology demands integration of careful geriatric assessment and management. This article provides an overview of basic biology of aging and its relationship with cancer. After a brief introduction about the definition and mechanisms of aging, as well as age-related biological and physiological changes, the discussion mainly focuses on recent development and insights into the relationship of frailty, inflammation, and immunity with cancer, highlighting how the new knowledge can help further improve assessment and treatment of older patients with malignancies and promote cancer research.
Arthropathies in Inflammatory Bowel Disease
Authors: Wiens Jeremy , Rankin James A. , Then Karen L.
Published: July 2017

Inflammatory bowel disease (IBD) is a systemic, chronic autoimmune disease of the digestive tract. The etiology and pathophysiology of IBD is not fully understood, though it is believed to be due to a complex interaction among the patient's genotype, immune system, and environmental factors. Inflammatory bowel disease is frequently accompanied by extraintestinal manifestations that occur in almost half of all patients. The most common extraintestinal manifestation that occurs is joint disease, collectively termed the arthropathies of IBD. While epidemiological studies have estimated that the arthropathies of IBD occur in over 46% of the IBD population, there is a paucity of nursing literature concerning the extraintestinal manifestations of IBD and the role of nurses in patient care. Thus, the purpose of this article is to facilitate a greater understanding for nurses and nurse clinicians regarding the arthropathies associated with IBD including classifications, pathophysiology, diagnosis, and management.
Laparoscopic Intragastric Surgery With Endoscopic Assistance: A 2 Gastrostomy Approach With Multiple Applications
Authors: Gabriel Emmanuel , Rosso Kelly , Shahab Danish , Shah Rupen , Bain Andrew , Kukar Moshim , Hochwald Steven N.
Published: July 2017

Purpose:

Laparoscopic intragastric resection is a surgical modality with acceptable oncologic outcomes for gastrointestinal stromal tumors and leiomyomas, particularly for masses located near the gastroesophageal junction (GEJ). We describe our technique of 2 gastrostomy laparoscopic, intragastric resection with endoscopic assistance.

Methods:

We detail our technique and report a unique application of this versatile approach.

Results:

Between December 2015 and July 2016, 4 patients underwent our combined technique of intragastric surgery. Complete resection was performed in the 2 patients who had gastrointestinal stromal tumors and 1 patient with a leiomyoma without complications. One patient had the unique diagnosis of gastritis cystica profunda. This mass could not be resected, but an effective Tru-cut core needle biopsy was obtained, and the mass was able to be diagnosed and decompressed.

Conclusions:

Our technique of 2 gastrostomy laparoscopic intragastric surgery is feasible and offers an effective oncologic approach for resection of tumors near the GEJ.
Revelation of the Genetic Basis for Convergent Innovative Anal Fin Pigmentation Patterns in Cichlid Fishes
Authors: Gu Langyu , Xia Canwei
Published: July 2017

Determining whether convergent novelties share a common genetic basis is vital to understanding the extent to which evolution is predictable. The convergent evolution of innovative anal fin pigmentation patterns in cichlid fishes is an ideal model for studying this question. Here, we focused on two patterns: 1) egg-spots, circular pigmentation patterns with different numbers, sizes and positions; and 2) the blotch, irregular pattern with no variation among species. How these two novelties originate and evolve remains unclear. Based on a thorough comparative transcriptomic and genomic analysis, we observed a common genetic basis with high evolutionary rates and similar expression levels between egg-spots and the blotch. But the associations of common genes with transcription factors and signalling pathways in the core gene network, as well as the integration of advantageous genes were observed specifically for egg-spots. Focusing on the whole transcriptomic level instead of limited numbers of candidate genes can explain the opposite conclusion between our study and the one from Santos et al. (2016), which suggested that no common genetic basis is shared between the blotch and egg-spots. Here, we propose that the re-use of the common genetic basis indicates important conservative functions (e.g., toolkit genes) for the origin of these convergent novel phenotypes, whereas independently evolved associations of common genes with transcription factors and signalling pathways (intrinsic factor) can free the evolution of egg-spots, and together with the integration of advantageous genes (extrinsic factor) can provide a clue to link egg-spots as a key innovation to the adaptive radiation in cichlid fishes. This hypothesis will further illuminate the mechanism of the origin and evolution of novelties in a broad sense.
Causal Role of Beta Oscillations in Time Estimation
Authors: Wiener Martin , Parikh Alomi , Krakow Arielle , Coslett H. Branch
Published: July 2017

The neural mechanisms underlying time perception are of vital importance to a comprehensive understanding of behavior and cognition. Recent work has pointed to a supramodal role for beta oscillations in coordinating endogenous timing mechanisms for the purpose of measuring temporal intervals. However, the majority of this work has employed paradigms relying on timed motor responses, which are confounded by beta’s established role in motor movement. Further, no study to date has tested if the alteration of beta oscillations subsequently impacts timing. Here, we address these concerns and demonstrate for the first time a causal connection between beta oscillations and timing. To accomplish this, we first re-analyzed two, separate EEG datasets from psychophysical experiments (Wiener, et al. 2012; 2015) demonstrating that beta oscillations are associated with the retention and comparison of a memory standard for duration, and that transcranial magnetic stimulation (TMS) of the right supramarginal gyrus leads to an increase in midline beta power during the encoding of a temporal interval, corresponding with a longer perceived interval of time. Next, we conducted a study of 20 healthy human participants using transcranial alternating current stimulation (tACS), over frontocentral cortex, at alpha (10Hz) and beta (20Hz) frequencies, during a visual temporal bisection task, demonstrating that beta stimulation exclusively shifts the perception of time such that stimuli are reported as longer in length, while preserving precision. Finally, we decomposed trial-by-trial choice data with a drift diffusion model of decision making and temporal encoding that reveals the shift in timing is caused by a change in the starting point of accumulation, rather than the drift rate or threshold. Our results provide causal evidence of beta’s involvement in the perception of time, and point to a specific role for beta oscillations in the encoding and retention of memory for temporal intervals.
Measurement Error Correction of Genome-Wide Polygenic Scores in Prediction Samples
Authors: Tucker-Drob Elliot M.
Published: July 2017

Abstract/Introduction

DiPrete, Burik, & Koellinger (2017;http://dx.doi.org/10.1101/134197) propose using an instrumental variable (IV) framework to correct genome-wide polygenic scores (GPSs) for error, thereby producing disattenuated estimates of SNP heritability in predictions samples. They demonstrate their approach by producing two independent GPSs for Educational Attainment (“multiple indicators”) in a prediction sample (Health and Retirement Study; HRS) from independent sets of SNP regression weights, each computed from a different half of the discovery sample (EA2; Okbay et al. 2016), i.e. “by randomly splitting the GWAS sample that was used for [the GPS] construction.”

Here, I elucidate how a structural equation modeling (SEM) framework that specifies true score variance in GPSs as a latent variable can be used to derive an equivalent correction to the IV approach proposed by DiPrete et al. (2017). This approach, which is rooted in a psychometric modeling tradition, has a number of advantages: (1) it formalizes the assumed data-generating model, (2) it estimates all parameters of interest in a single step, (3) is can be flexibly incorporated into a larger multivariate analysis (such as the “Genetic Instrumental Variable” approach proposed by DiPrete et al., 2017), (4) it can easily be adapted to relax assumptions (e.g. that the GPS indicators equally represent the true genetic factor score), and (5) it can easily be extended to include more than two GPS indicators. After describing how the multiple indicator approach to GPS correction can specified as a structural equation model, I demonstrate how a structural equation modeling approach can be used to correct GPSs for error using SNP heritability obtained using GREML or LD score regression to produce a correction that is equivalent to an approach recently proposed by Daniel Benjamin and colleagues. Finally, I briefly discuss what I view as some conceptual limitations surrounding the error correction approaches described, regardless of the estimation method implemented.
Systematic selection of reference genes for normalization of circulating RNA transcripts in pregnant women based on RNA-seq data
Authors: Chim Stephen S. C. , Wong Karen K. W. , Chung Claire Y. L. , Lam Stephanie K. W. , Kwok Jamie S. L. , Lai Chit-Ying , Cheng Yvonne K. Y. , Hui Annie S. Y. , Meng Meng , Chan Oi-Ka , Tsui Stephen K. W. , Lee Keun-Young , Chan Ting-Fung , Leung Tak-Yeung
Published: July 2017

RNA transcripts circulating in peripheral blood represent an important source of non-invasive biomarkers. To accurately quantify the levels of a circulating transcript, one needs to normalize the data with internal control reference genes, which are detected at relatively constant levels across different blood samples. A few stably-expressed reference gene candidates have to be selected from transcriptome data before validation of their stable expression by reverse-transcription quantitative polymerase chain reaction. However, there is a lack of transcriptome, let alone whole-transcriptome, data from maternal blood. To overcome this shortfall, we performed RNA-seq on blood samples from women presented with preterm labor. Of 11215 exons detected in the maternal blood whole-transcriptome, we systematically identified a panel of 395 genes comprising exons that were detected at acoefficient of variation(CV) ranging from 7.75%-17.7%. Their levels were considerably less variable than anyGAPDHexon (minimumCV, 27.3%). Upon validation, selected genes from this panel remained as more stably expressed thanGAPDHin maternal blood. This panel is over-represented with genes involved with actin cytoskeleton, macromolecular complex and the integrin signaling pathway. This groundwork provides a starting point for systematically selecting reference gene candidates for normalizing the levels of circulating RNA transcripts in maternal blood.
Comment on “Magnetosensitive neurons mediate geomagnetic orientation in Caenorhabditis elegans”
Authors: Landler Lukas , Nimpf Simon , Hochstoeger Tobias , Nordmann Gregory Charles , Papadaki-Anastasopoulou Artemis , Keays David Anthony
Published: July 2017

A diverse array of species on the planet employ the Earth’s magnetic field as a navigational aid. As the majority of these animals are migratory, their utility to interrogate the molecular and cellular basis of the magnetic sense is limited. Vidal-Gadea and colleagues recently argued that the wormC. eleganspossesses a magnetic sense that guides their vertical movement in soil. In making this claim they relied on three different behavioural assays that involved magnetic stimuli. Here, we set out to replicate their results employing blinded protocols and double wrapped coils that control for heat generation. We find no evidence supporting the existence of a magnetic sense inC. elegans. We further show that the Vidal-Gadea hypothesis is problematic as the adoption of a correction angle and a fixed trajectory relative to the Earth’s magnetic inclination does not necessarily result in vertical movement.
Wisdom of artificial crowds feature selection in untargeted metabolomics: An application to the development of a blood-based diagnostic test for thrombotic myocardial infarction
Authors: Trainor Patrick J. , Yampolskiy Roman V. , DeFilippis Andrew P.
Published: July 2017

Introduction

Heart disease remains a leading cause of global mortality. While acute myocardial infarction (colloquially: heart attack), has multiple proximate causes, proximate etiology cannot be determined by a blood-based diagnostic test. We enrolled a suitable patient cohort and conducted an untargeted quantification of plasma metabolites by mass spectrometry for developing a test that can differentiate between thrombotic MI, non-thrombotic MI, and stable disease. A significant challenge in developing such a diagnostic test is solving the NP-hard problem of feature selection for constructing an optimal statistical classifier.

Objective

We employed a Wisdom of Artificial Crowds (WoAC) strategy for solving the feature selection problem and evaluated the accuracy and parsimony of downstream classifiers in comparison with embedded feature selection via the Lasso and Elastic Net.

Materials and Methods

Artificial Crowd Wisdom was generated via aggregation of the best solutions from independent and diverse genetic algorithm populations that were initialized with bootstrapping and a random subspaces constraint.

Results / Conclusions

WoAC feature selection performed favorably compared to Lasso and Elastic Net solutions. The classifier constructed following WoAC feature selection had a cross-validation estimated misclassification rate of 2.6% as compared to 26.3% via the Lasso and 18.5% via an Elastic Net. The classifier warrants further evaluation as a diagnostic test in an independent cohort.
Compositional shifts in the root microbiota track the life-cycle of field-grown rice plants
Authors: Edwards Joseph , Santos-Medellín Christian , Liechty Zachary , Nguyen Bao , Lurie Eugene , Eason Shane , Phillips Gregory , Sundaresan Venkatesan
Published: July 2017

Bacterial communities associated with roots impact the health and nutrition of the host plant. While a multitude of static factors are known to influence the composition of the root-associated microbiota, the dynamics of these microbial assemblies over the plant life cycle are poorly understood. Here, we use dense temporal sampling of spatial compartments to characterize the root-associated microbiota of field grown rice (Oryza sativa)over the course of three consecutive growing seasons and two sites in diverse geographic regions. The root microbiota was found to be highly dynamic during the vegetative phase of plant growth, then stabilizes compositionally for the remainder of the life cycle. Bacterial taxa conserved between field sites can be used as predictive features of rice plant age by modeling using a random forests approach. The age-prediction models were used to reveal that drought stressed plants have developmentally delayed microbiota compared to unstressed plants. Further, by using genotypes with varying developmental rates, we show that shifts in the microbiome are correlated with rates of developmental transitions rather than age alone, such that different microbiota compositions reflect juvenile and adult life stages. These results suggest a model for successional dynamics of the root-associated microbiota over the plant life cycle.
Simulation of electrical machines: a FEM-BEM coupling scheme
Authors: Kielhorn Lars , Rüberg Thomas , Zechner Jürgen
Published: July 2017

Purpose

Electrical machines commonly consist of moving and stationary parts. The field simulation of such devices can be demanding if the underlying numerical scheme is solely based on a domain discretization, such as in the case of the finite element method (FEM). This paper aims to present a coupling scheme based on FEM together with boundary element methods (BEMs) that neither hinges on re-meshing techniques nor deals with a special treatment of sliding interfaces. While the numerics are certainly more involved, the reward is obvious: the modeling costs decrease and the application engineer is provided with an easy-to-use, versatile and accurate simulation tool.

Design/methodology/approach

The authors present the implementation of a FEM-BEM coupling scheme in which the unbounded air region is handled by the BEM, while only the solid parts are discretized by the FEM. The BEM is a convenient tool to tackle unbounded exterior domains, as it is based on the discretization of boundary integral equations (BIEs) that are defined only on the surface of the computational domain. Hence, no meshing is required for the air region. Further, the BIEs fulfill the decay and radiation conditions of the electromagnetic fields such that no additional modeling errors occur.

Findings

This work presents an implementation of a FEM-BEM coupling scheme for electromagnetic field simulations. The coupling eliminates problems that are inherent to a pure FEM approach. In detail, the benefits of the FEM-BEM scheme are: the decay conditions are fulfilled exactly, no meshing of parts of the exterior air region is necessary and, most importantly, the handling of moving parts is incorporated in an intriguingly simple manner. The FEM-BEM formulation in conjunction with a state-of-the-art preconditioner demonstrates its potency. The numerical tests not only reveal an accurate convergence behavior but also prove the algorithm to be suitable for industrial applications.

Originality/value

The presented FEM-BEM scheme is a mathematically sound and robust implementation of a theoretical work presented a decade ago. For the application within an industrial context, the original work has been extended by higher-order schemes, periodic boundary conditions and an efficient treatment of moving parts. While not intended to be used under all circumstances, it represents a powerful tool in case that high accuracies together with simple mesh-handling facilities are required.
Thermo-electric simulation of battery-modules with reduced order modelling of linear electrical components
Authors: Pichler Franz , Koester Niels , Thaler Alexander
Published: July 2017

Purpose

This paper aims to present a fully coupled thermo-electrical finite-element battery model with an applied model-order reduction. The model is used to analyse the thermal design of battery modules during typical drive-cycles of electric vehicles.

Design/methodology/approach

A model-order reduction is applied, in which the electrical linear bus-bars are analysed in an a-priori step. For these bus-bars, special distributed basis-functions are computed, which make the solution of differential Ohm's law unnecessary during the transient simulation. Furthermore, the distributed basis-functions are used to strongly couple the non-linear battery models, which reduces the iterations needed to simulate them.

Findings

Altogether, this results in a fast simulation scheme for coupled linear and non-linear electrical components and their thermal behaviour.

Originality/value

The presented method delivers an innovative approach, on how to systematically minimize the computational effort in a system of linear and non-linear electrical components, while keeping the full three-dimensional information of the original problem.
Non-iterative object detection methods in electrical tomography for robotic applications
Authors: Mühlbacher-Karrer Stephan , Padilha Leitzke Juliana , Faller Lisa-Marie , Zangl Hubert
Published: July 2017

Purpose

This paper aims to investigate the usability of the non-iterative monotonicity approach for electrical capacitance tomography (ECT)-based object detection. This is of particular importance with respect to object detection in robotic applications.

Design/methodology/approach

With respect to the detection problem, the authors propose a precomputed threshold value for the exclusion test to speed up the algorithm. Furthermore, they show that the use of an inhomogeneous split-up strategy of the region of interest (ROI) improves the performance of the object detection.

Findings

The proposed split-up strategy enables to use the monotonicity approach for robotic applications, where the spatial placement of the electrodes is constrained to a planar geometry. Additionally, owing to the improvements in the exclusion tests, the selection of subregions in the ROI allows for avoiding self-detection. Furthermore, the computational costs of the algorithm are reduced owing to the use of a predefined threshold, while the detection capabilities are not significantly influenced.

Originality/value

The presented simulation results show that the adapted split-up strategies for the ROI improve significantly the detection performance in comparison to the traditional ROI split-up strategy. Thus, the monotonicity approach becomes applicable for ECT-based object detection for applications, where only a reduced number of electrodes with constrained spatial placement can be used, such as in robotics.
Frequency dependent resistance calculation of multiple conductors
Authors: Župan Tomislav , Trkulja Bojan
Published: July 2017

Purpose

The purpose of this paper is to present a method for calculating frequency-dependent resistance when multiple current-carrying conductors are present.

Design/methodology/approach

Analytical and numerical formulations are presented. Both skin- and proximity-effects are considered in the numerical approach, whereas only skin-effect can be taken into account in analytical equations. The calculation is done using a self-developed integral equation-based field solver. The results are benchmarked using professional software based on the finite element method (FEM).

Findings

Results from the numerical approach are in agreement with FEM-based software throughout the whole frequency range. Analytical formulations yield unsatisfactory results in higher frequency range. When multiple conductors are mutually relatively close, the proximity-effect has an impact on effective resistance and has to be taken into account.

Research limitations/implications

The methodology is presented using axially symmetrical conductors. However, the same procedure can be developed for straight conductors as well.

Practical implications

Presented fast and stable procedure can be used in most electromagnetic devices when frequency-dependent resistance needs to be precisely determined.

Originality/value

The value of the presented numerical methodology lies in its ability to take both skin- and proximity-effects into account. As conductors are densely packed in most electromagnetic devices, both effects influence the effective resistance. The method can be easily implemented using a self-developed solver and yields satisfactory results.
Rigorous time-domain analysis of statistically oriented graphene sheet fluctuations
Authors: Papadimopoulos Athanasios N. , Amanatiadis Stamatios A. , Kantartzis Nikolaos V. , Zygiridis Theodoros T. , Tsiboukis Theodoros D.
Published: July 2017

Purpose

Important statistical variations are likely to appear in the propagation of surface plasmon polariton waves atop the surface of graphene sheets, degrading the expected performance of real-life THz applications. This paper aims to introduce an efficient numerical algorithm that is able to accurately and rapidly predict the influence of material-based uncertainties for diverse graphene configurations.

Design/methodology/approach

Initially, the surface conductivity of graphene is described at the far infrared spectrum and the uncertainties of its main parameters, namely, the chemical potential and the relaxation time, on the propagation properties of the surface waves are investigated, unveiling a considerable impact. Furthermore, the demanding two-dimensional material is numerically modeled as a surface boundary through a frequency-dependent finite-difference time-domain scheme, while a robust stochastic realization is accordingly developed.

Findings

The mean value and standard deviation of the propagating surface waves are extracted through a single-pass simulation in contrast to the laborious Monte Carlo technique, proving the accomplished high efficiency. Moreover, numerical results, including graphene’s surface current density and electric field distribution, indicate the notable precision, stability and convergence of the new graphene-based stochastic time-domain method in terms of the mean value and the order of magnitude of the standard deviation.

Originality/value

The combined uncertainties of the main parameters in graphene layers are modeled through a high-performance stochastic numerical algorithm, based on the finite-difference time-domain method. The significant accuracy of the numerical results, compared to the cumbersome Monte Carlo analysis, renders the featured technique a flexible computational tool that is able to enhance the design of graphene THz devices due to the uncertainty prediction.
Cannabis and psychosis: the impact of polydrug use
Authors: Shevlin Mark , McElroy Eoin , Murphy Jamie , Hyland Philip , Vallieres Frédérique , Elklit Ask , Christoffersen Mogens
Published: July 2017

Purpose

While research has consistently identified an association between cannabis use and psychosis, few studies have examined this relationship in a polydrug context (i.e. combining cannabis with other illicit substances). The paper aims to discuss this issue.

Design/methodology/approach

The present study sought to examine the association between recreational drug use (cannabis only vs polydrug) and psychotic disorders. Analysis was conducted on a large, representative survey of young Danish people aged 24 (n=4,718). Participants completed self-report measures of lifetime drug use and this information was linked to the Danish psychiatric registry system.

Findings

Multivariate binary logistic regression analysis was used to examine the association between drug use (no drug use, cannabis only, cannabis and other drug) and ICD-10 psychotic disorders, while controlling for gender and parental history of psychosis. Compared with no drug use, the use of cannabis only did not increase the risk of psychosis while the odds ratio for cannabis and other drug were statistically significant.

Research limitations/implications

Psychosis risk may be associated with the cumulative effect of polydrug use.

Practical implications

Cannabis use may be a proxy for other drug use in research studies.

Originality/value

This study is innovative as it uses linked self-report and administrative data for a large sample. Administrative data were used to as an objective mental health status indicator.
Heroin-induced toxic leukoencephalopathy – “chasing the dragon” in South Africa
Authors: Schutte Clara Maria , Sasikumar Sunayna , Nchoe Keorapetse , Kakaza Mandisa , Ueckermann Veronica , Van der Meyden Cornelius H.
Published: July 2017

Purpose

In South Africa, many illicit drugs have only recently been introduced and drug-related complications are often new to treating physicians. Heroin-induced leukoencephalopathy has been reported elsewhere in patients who inhale heated heroin vapors, a method known as “chasing the dragon.” The purpose of this paper is to present two patients, known to have inhaled heroin a few weeks prior to presenting with progressive neurological deficits.

Design/methodology/approach

Case presentations: two young males presented independently within eight weeks of one another with progressive slurring of speech, incoordination and weakness of the limbs over a period of two to three weeks. Both were known heroin addicts, and were known to one another, and both had inhaled heroin prior to the onset of symptoms.

Findings

The patients presented with a pancerebellar syndrome with marked bilateral upper motor neuron signs. CT scans showed diffuse symmetrical hypodense lesions involving the cerebral and cerebellar white matter with normal CSF. Both patients deteriorated neurologically, became cardiovascularly unstable and demised. Postmortem in one of the patients showed a prominent spongiform leukoencephalopathy consistent with reports of heroin-inhalation injury to the brain.

Research limitations/implications

Toxic leukoencephalopathy due to heroin vapor inhalation was first described in the Netherlands in 1982. It has not been reported to occur with other modes of heroin use; an unknown toxin contained in heroin pyrolysate which forms when heroin is heated, may be causative. Brain MRI typically shows diffuse, symmetrical white matter hyperintensities on T2 and fluid-attenuated inversion recovery sequences in the cerebellum, posterior cerebrum and posterior limbs of the internal capsule with a posterior-anterior gradient. Pathologically, spongiform degeneration with relative sparing of subcortical U-fibers is seen. No treatment has been proven effective, but antioxidants and Vitamin E may be beneficial. Mortality is high at 23-48 percent.

Practical implications

This report emphasizes that spongiform leukoencephalopathy as a rare consequence of inhaling heroin vapors does occur in South Africa and clinicians should consider this disorder in their differential diagnosis of acutely developing leukoencephalopathy.

Social implications

An awareness program regarding this grave condition is planned.

Originality/value

The cardiovascular complications of patients inhaling heroin vapor has not been highlighted previously. These are the first patients from Africa described with this condition. A toxic component appears likely.
Gender-specific human capital: identification and quantifying its wage effects
Authors: Tverdostup Maryna , Paas Tiiu
Published: July 2017

Purpose

The purpose of this paper is to better understand the possible reasons behind gender pay disparities, focussing on the unique features of male and female human capital and their wage returns. Despite increasing convergence of male and female human capital attainments, substantial differences remain. Extraction of human capital components non-overlapping across genders provides more profound explanation of the unexplained wage gap of men and women.

Design/methodology/approach

Starting with the non-parametric matching-based decomposition technique, the authors extend the pay gap estimation framework and focus on males and females having no counterpart in a set of characteristics within the opposite gender. The authors identify gender-unique human capital in terms of differences in distribution of individual characteristics across men and women and gender-specific combination of human capital characteristics. Wage returns to gender-specific profiles are evaluated applying wage regression on both full distribution of earnings and wage quantiles. The research relies on the Survey of Adult Skills (PIAAC) database for Estonia, which incorporates both formal education and cognitive skill records.

Findings

The study identifies sets of characteristics and competencies exclusive for both genders, proving that male and female profiles cannot be directly compared. The results suggest that men possess high individual and combined abilities in numeracy and problem solving in technology-rich environment, not always reached by females. This potentiates men’s higher earnings in spite of their generally lower formal educational attainments. Wage gap analysis over the full distribution of earnings shows even larger “glass ceiling” effect for females, possessing woman-specific human capital.

Originality/value

The authors raise a research from a novel perspective towards a role of human capital in gender wage inequality. Instead of usual reference to observable gaps in male and female characteristics, the authors identify the gender-specific human capital profiles, to a large extent non-reached by the opposite gender. Analysed associations between gender-specific characteristics and earnings provide an insight to possible effects of gender-unique human capital on a male-female wage disparity.
Business cooperatives: when does sharing become a drawback?
Authors: Roux Benoît , Plé Loïc
Published: July 2017

Purpose

Cooperatives are relatively understudied compared with investor-owned companies, yet their economic impact makes them important to consider. This study is to focus on business cooperatives that gather firms or entrepreneurs that share the same social and economic motivations and need to ally to grow. The positive and negative consequences of membership on the members’ business models are detailed. Insights to address and prevent the detrimental influences of membership on members’ business model are provided.

Design/methodology/approach

This conceptual study relies on several business cases to suggest that cooperative membership comes with positive and detrimental consequences for the three dimensions of members’ business models: their organization, resources and competences and value propositions (i.e. members’ offers).

Findings

Because organization, resources and competences, and value propositions are affected by membership in a cooperative, business members’ control over their own business models may diminish. This can offer positive consequences but may also be too constraining and harmful in the long term.

Research limitations/implications

Only scant research has investigated the influence of cooperatives on members’ business models. Further studies could help firms and entrepreneurs maximize the advantages of their membership in cooperatives while limiting the detrimental consequences over time.

Practical implications

If they are aware of the potential drawbacks of business cooperative membership, members can implement proactive efforts to avoid losing control of their business models.

Originality/value

Prior literature mainly concentrates on how cooperatives work and develop. No prior study seems to have investigated the consequences of cooperatives’ membership on members’ business models.
Intellectual capital disclosures in an emerging economy: status and trends
Authors: Sharma Sarishma , Dharni Khushdeep
Published: July 2017

Purpose

The purpose of this paper is to study the status and trend of intellectual capital disclosures by selected companies in India. Three categories of intellectual capital disclosures across six industry groups were measured. The relation of the three categories of disclosures, i.e. human capital, relational capital and structural capital disclosures with the measures of organisational performance such as sales, R&D, R&D intensity, net profit and export intensity has also been studied.

Design/methodology/approach

Based on National Industrial Classification 2008, six sectors, namely pharmaceutical, basic metals, industrial manufacturing, energy, financial services and information technology were included in the study and 20 companies were selected from each sector based on the availability of data from 2004-2005 to 2013-2014, thus, making a sample of 1,200 firm-years. For collecting the data, a list of keywords related to various dimensions of intellectual capital was prepared and the count of keywords was searched in the annual reports of the companies.

Findings

Significant and positive trend coefficients were found in the majority of the sectors. Analysis revealed that trend coefficients differed across various sectors indicating the presence of sector specificity. Results of trend analysis reveal that structural capital-related disclosures have stagnated in case of pharmaceutical sector after hitting the peak. Significant variations were found across sectors in terms of all three types of intellectual capital disclosures. Results of study empirically support the fact that intellectual capital disclosures tend to increase with size of the organisation.

Research limitations/implications

As data have been collected from annual reports of the companies, the accuracy of the findings is limited to the accuracy of the reported data.

Originality/value

The study is an original piece of work. This study provides an insight into the disclosure trend of intellectual capital in an emerging economy.
Enhancing radical innovation performance through intellectual capital components
Authors: Agostini Lara , Nosella Anna
Published: July 2017

Purpose

In today’s knowledge economy the ability to innovate and develop new products is a key factor to sustain firm performance. Within this context, analysing the role of different components of intellectual capital (IC) becomes of foremost importance, as well as an under-investigated issue for small- and medium-sized enterprises (SMEs). The purpose of this paper is to investigate the impact of human, organisational and relational capital (RC) on radical innovation performance (RIP), as well as to examine whether organisational capital (OC) and RC mediate the relationship between human capital (HC) and RIP and whether OC moderates the relationship between RC and RIP.

Design/methodology/approach

The methodology consisted of a factor analysis and different regression models to test for mediation and moderation. The analyses are carried out on a sample of 150 micro firms and SMEs involved in the production of machinery or instruments and located in Italy.

Findings

Results show that HC is directly associated to RIP, as well as OC and RC that totally mediate the relationship between HC and RIP. Moreover, OC positively moderates the relationship between RC and RIP.

Originality/value

This study is particularly interesting because it adopts an overarching perspective on IC testing the interplay between the different components of IC. In addition, it focusses on the SME context which is under-investigated as far as IC and performance measurement is concerned.
Balanced scorecard in higher education institutions
Authors: Reda Nigusse W.
Published: July 2017

Purpose

The purpose of this paper is twofold: first, to highlight the congruence and roles of the balanced scorecard in the quality assurance practices in higher education institutions, and second, to propose a balanced scorecard model for higher education institutions.

Design/methodology/approach

A descriptive literature review was used to understand the balanced scorecard, quality assurance practice (System model) and characteristics of the higher education institutions.

Findings

Used appropriately, the philosophical tenets of the perspectives of the balanced scorecard seem to be congruent with the input, process and output dimensions of quality assurance practices. Thus, if the core functions of higher education are explicitly represented in each perspective, the balanced scorecard seems important for materializing the input, process and output dimensions of quality assurance in higher education institutions. It may help to track and measure the status of higher education institutions in each quality assurance dimension and ultimately help to align each dimension with the university’s vision.

Research limitations/implications

The paper relied on the description of previous literature. Therefore, as it did not depend on the empirical evidences, the conclusions derived in the paper are more argumentative.

Practical implications

The paper will add an input to the ongoing discussions on the applications of the balanced scorecard to higher education institutions. Moreover, the proposed model of the balanced scorecard may help higher education managers to assess the performances of higher education institutions and their academic disciplines according to their areas of excellence.

Originality/value

This paper attempts to undertake a literature review on the balanced scorecard and its roles to the quality assurance practices in higher education. In addition, the congruence between the balanced scorecard and the contemporary characteristics of the higher education institutions is also explored.