bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Fatigue on Balance in Individuals With Parkinson Disease: Influence of Medication and Brain-Derived Neurotrophic Factor Genotype
Authors: Baer Michael , Klemetson Bradley , Scott Diana , Murtishaw Andrew S. , Navalta James W. , Kinney Jefferson W. , Landers Merrill R.
Published: March 2018

Background and Purpose:

Because falls can have deleterious consequences, it is important to understand the influence of fatigue and medications on balance in persons with Parkinson disease (PD). Thus, the purpose of this study was to investigate the effects of fatigue on balance in individuals with PD. Because brain-derived neurotrophic factor (BDNF) has been shown to be related to motor performance, we also explored its role.

Methods:

A total of 27 individuals (age = 65.4 ± 8.1 years; males = 14, females = 13) with neurologist-diagnosed PD with 13 genotyped for BDNF as Val66Val, 11 as Val66Met, 2 as Met66Met (1 refused). Participants were tested both on and off medication, 1 week apart. On both days, they completed a pre- and posttest separated by a fatiguing condition. Factorial analyses of variance were performed for the following balance domains: (1) anticipatory postural responses; (2) adaptive postural responses; (3) dynamic balance; (4) sensory orientation; and (5) gait kinematics. For BDNF, t-tests were conducted comparing genotype for the pre-post difference scores in both the on and off medication states.

Results:

There were no interactions between time (pre- and postintervention) and medication for any of the domains (Ps ≥ 0.187). Participants with BDNF Met alleles were not significantly different from Val66Val participants in balance (Ps ≥ 0.111) and response to a fatiguing condition (Ps ≥ 0.070).

Discussion and Conclusions:

Fatigue does not appear to have a detrimental effect on balance, and there was not a differential effect of medication in individuals with PD. These results also indicate that participants with a BDNF Met allele did not have a greater decay in function after a fatiguing condition.

Video Abstract availablefor more insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A196).
NTRK Fusions Define a Novel Uterine Sarcoma Subtype With Features of Fibrosarcoma
Authors: Chiang Sarah , Cotzia Paolo , Hyman David M. , Drilon Alexander , Tap William D. , Zhang Lei , Hechtman Jaclyn F. , Frosina Denise , Jungbluth Achim A. , Murali Rajmohan , Park Kay J. , Soslow Robert A. , Oliva Esther , Iafrate A. John , Benayed Ryma , Ladanyi Marc , Antonescu Cristina R.
Published: March 2018

Tropomyosin receptor kinase (Trk) inhibitors have shown high response rates in patients with tumors harboring NTRK fusions. We identified 4 NTRK fusion-positive uterine sarcomas that should be distinguished from leiomyosarcoma and undifferentiated uterine sarcoma. NTRK rearrangements were detected by fluorescence in situ hybridization (FISH) and/or targeted RNA or DNA sequencing in 4 undifferentiated uterine sarcomas with spindle cell morphology. Because of histologic overlap with leiomyosarcoma, TrkA and pan-Trk immunohistochemistry was performed in 97 uterine leiomyosarcomas. NTRK1 and NTRK3 FISH was performed on tumors with TrkA or pan-Trk staining. We also performed whole transcriptome RNA sequencing of a leiomyosarcoma with TrkA expression and targeted RNA sequencing of 2 additional undifferentiated uterine sarcomas. FISH and/or targeted RNA or DNA sequencing in the study group showed TPM3-NTRK1, LMNA-NTRK1, RBPMS-NTRK3, and TPR-NTRK1 fusions. All tumors were composed of fascicles of spindle cells. Mitotic index was 7 to 30 mitotic figures per 10 high power fields; tumor necrosis was seen in 2 tumors. Desmin, estrogen receptor, and progesterone receptor were negative in all tumors, while pan-Trk was expressed in all tumors with concurrent TrkA staining in 3 of them. TrkA and/or pan-Trk staining was also seen in 6 leiomyosarcomas, but these tumors lacked NTRK fusions or alternative isoforms by FISH or whole transcriptome sequencing. No fusions were detected in 2 undifferentiated uterine sarcomas. NTRK fusion-positive uterine spindle cell sarcomas constitute a novel tumor type with features of fibrosarcoma; patients with these tumors may benefit from Trk inhibition. TrkA and pan-Trk expression in leiomyosarcomas is rare and does not correlate with NTRK rearrangement.
An Acute Bout of Aquatic Treadmill Exercise Induces Greater Improvements in Endothelial Function and Postexercise Hypotension Than Land Treadmill Exercise
Authors: Joubert Dustin P. , Granados Jorge Z. , Oliver Jonathan M. , Noack Bethany L. , Grandjean Peter W. , Woodman Christopher R. , Riechman Steven E. , Crouse Stephen F.
Published: March 2018

Objective

The purpose of the study was to compare acute bouts of aquatic treadmill (ATM) and land treadmill (LTM) exercise on flow-mediated dilation, postexercise blood pressure, plasma nitrate/nitrite, and atrial natriuretic peptide in untrained, prehypertensive men.

Design

In a counterbalanced, crossover design, 19 untrained, prehypertensive men completed bouts of ATM and LTM on separate days. Flow-mediated dilation was measured pre-exercise and 1-hr postexercise. Blood samples were obtained pre-exercise and immediately postexercise and analyzed for plasma nitrate/nitrite and atrial natriuretic peptide. A magnitude-based inference approach to inference was used for statistical analysis.

Results

A possible clinically beneficial increase in flow-mediated dilation (1.2%, 90% confidence interval = −0.07% to 2.5%) was observed 1 hr after ATM. In contrast, a possible clinically harmful decrease in flow-mediated dilation (−1.3%, 90% confidence interval = −2.7% to 0.2%) was observed 1 hr after LTM. The magnitude of the postexercise systolic blood pressure reduction was greater after ATM (−4.9, SD = 2.9 mm Hg) than LTM (−2.6, SD = 2.5 mm Hg). Atrial natriuretic peptide increased 34.3 (SD = 47.0%) after ATM and decreased −9.0 (SD = 40.0%) after LTM.

Conclusions

An acute bout of ATM induced a more favorable endothelial response and greater postexercise hypotensive response than LTM. These changes were associated with increased atrial natriuretic peptide levels after ATM.
A role for pericytes in chronic pain?
Authors: Durrant Alexandra M. , Swift Matthew N. , Beazley-Long Nicholas
Published: March 2018

Purpose of review

The importance of the blood–brain barrier (BBB) and neuroinflammation in neurodegenerative conditions is becoming increasingly apparent, yet very little is known about these neurovascular functions in nonmalignant disease chronic pain. Neural tissue pericytes play critical roles in the formation and maintenance of the BBB. Herein, we review the important roles of neural pericytes and address their potential role in chronic pain.

Recent findings

Pericytes are implicated in the function of neural microvasculature, including BBB permeability, neuroimmune factor secretion and leukocyte transmigration. In addition, the multipotent stem cell nature of pericytes affords pericytes the ability to migrate into neural parenchyma and differentiate into pain-associated cell types. These recent findings indicate that pericytes are key players in pathological BBB disruption and neuroinflammation, and as such pericytes may be key players in chronic pain states.

Pericytes play key roles in pathological processes associated with chronic pain. We propose that pericytes may be a therapeutic target for painful diseases that have associated neural vascular dysfunction. Given the paucity of new pharmacotherapies for chronic pain conditions, we hope that this review inspires researchers to unearth the potential role(s) of pericytes in chronic pain sowing the seeds for future new chronic pain therapies.
Quantum probability and Hilbert’s sixth problem
Authors: Accardi Luigi
Published: March 2018

With the birth of quantum mechanics, the two disciplines that Hilbert proposed to axiomatize, probability and mechanics, became entangled and a new probabilistic model arose in addition to the classical one. Thus, to meet Hilbert’s challenge, an axiomatization should account deductively for the basic features of all three disciplines. This goal was achieved within the framework of quantum probability. The present paper surveys the quantum probabilistic axiomatization.

This article is part of the themed issue ‘Hilbert’s sixth problem’.
CLADES: A Classification-based Machine Learning Method for Species Delimitation from Population Genetic Data
Authors: Pei Jingwen , Chu Chong , Li Xin , Lu Bin , Wu Yufeng
Published: March 2018

Species are considered to be the basic unit of ecological and evolutionary studies. Since multi-locus genomic data are becoming increasingly available, there has been considerable interests in the use of DNA sequence data to delimit species. In this paper, we show that machine learning can be used for species delimitation. There exists no species delimitation methods that are based on machine learning. Our method treats the species delimitation problem as a classification problem. It is a problem of identifying the category of a new observation on the basis of training data. Extensive simulation is first conducted over a broad range of evolutionary parameters for training purpose. Each pair of known populations are combined to form training samples with a label of “same species” or “different species”. We use Support Vector Machine (SVM) to train a classifier using a set of summary statistics computed from training samples as features. The trained classifier can classify a test sample to two outcomes: “same species” or “different species”. Given multi-locus genomic data of multiple related organisms or populations, our method (called CLADES) performs species delimitation by first classifying pairs of populations. CLADES then delimits species by maximizing the likelihood of species assignment for multiple populations. CLADES is evaluated through extensive simulation and also tested on real genetic data. We show that CLADES is both accurate and efficient for species delimitation when compared with existing methods. CLADES can be useful especially when existing methods have difficulty in delimitation, e.g. with short species divergence time and gene flow.
A Measure of Open Data: A Metric and Analysis of Reusable Data Practices in Biomedical Data Resources
Authors: Carbon Seth , Champieux Robin , McMurry Julie , Winfree Lilly , Wyat Letisha R. , Haendel Melissa
Published: March 2018

Data is the foundation of science, and there is an increasing focus on how data can be reused and enhanced to drive scientific discoveries. However, most seemingly “open data” do not provide legal permissions for reuse and redistribution. Not being able to integrate and redistribute our collective data resources blocks innovation, and stymies the creation of life-improving diagnostic and drug selection tools. To help the biomedical research and research support communities (e.g. libraries, funders, repositories, etc.) understand and navigate the data licensing landscape, the (Re)usable Data Project (RDP) (http://reusabledata.org) assesses the licensing characteristics of data resources and how licensing behaviors impact reuse. We have created a ruleset to determine the reusability of data resources and have applied it to 56 scientific data resources (i.e. databases) to date. The results show significant reuse and interoperability barriers. Inspired by game-changing projects like Creative Commons, the Wikipedia Foundation, and the Free Software movement, we hope to engage the scientific community in the discussion regarding the legal use and reuse of scientific data, including the balance of openness and how to create sustainable data resources in an increasingly competitive environment.
New strains for tissue-specific RNAi studies in Caenorhabditis elegans
Authors: Watts Jason S. , Harrison Henry F. , Omi Shizue , Guenthers Quentin , Dalelio James , Pujol Nathalie , Watts Jennifer L.
Published: March 2018

RNA interference is a powerful tool for dissecting gene function. In Caenorhabditis elegans, ingestion of double stranded RNA causes strong, systemic knockdown of target genes. Further insight into gene function can be revealed by tissue-specific RNAi techniques. Currently available tissue-specific C. elegans strains rely on rescue of RNAi function in a desired tissue or cell in an otherwise RNAi deficient genetic background. We attempted to assess the contribution of specific tissues to polyunsaturated fatty acid (PUFA) synthesis using currently available tissue-specific RNAi strains. We discovered that rde-1 (ne219), a commonly used RNAi-resistant mutant strain, retains considerable RNAi capacity against RNAi directed at PUFA synthesis genes. By measuring changes in the fatty acid products of the desaturase enzymes that synthesize PUFAs, we found that the before mentioned strain, rde-1 (ne219) and the reported germline only RNAi strain, rrf-1 (pk1417) are not appropriate genetic backgrounds for tissue-specific RNAi experiments. However, the knockout mutant rde-1 (ne300) was strongly resistant to dsRNA induced RNAi, and thus is more appropriate for construction of a robust tissue-specific RNAi strains. Using newly constructed strains in the rde-1(null) background, we found considerable desaturase activity in intestinal, epidermal, and germline tissues, but not in muscle. The RNAi-specific strains reported in this study will be useful tools for C. elegans researchers studying a variety of biological processes.
Lilikoi: an R package for personalized pathway-based classification modeling using metabolomics data
Authors: Al-Akwaa Fadhl M. , Huang Sijia , Garmire Lana X.
Published: March 2018

Lilikoi (Hawaiian word for passion fruit) is a new and comprehensive R package for personalized pathway based classification modelling, using metabolomics data. Four basic modules are presented as the backbone of the package: 1) Feature mapping module, which standardizes the metabolite names provided by users, and map them to pathways. 2) Dimension transformation module, which transforms the metabolomic profiles to personalized pathway-based profiles using pathway deregulation scores (PDS). 3) Feature selection module which helps to select the significant pathway features related to the disease phenotypes, and 4) Classification and prediction module which offers various machine-learning classification algorithms. The package is freely available under the GPLv3 license through the github repository at: https://github.com/lanagarmire/lilikoi
Fast NeighborNet: Improving the Speed of the Neighbor-Net Phylogenetic Network Algorithm with Multithreading and a Relaxed Search Strategy
Authors: Porter Jacob
Published: March 2018

Fast Neighbor-Net is a command-line Java program that has fast implementations of the popular Neighbor-Net phylo-genetic split network approach. This allows more efficiency in computationally intensive tasks such as larger scale data analysis and bootstrapping. The canonical search phase iteratively finds a pair of connected components that minimizes a distance function in Θ(n3) time in the input taxa count. A relaxed search strategy has been implemented that has averagecase time complexity of𝒪(n2logn) but with Θ(n3) worst-case time complexity. This search strategy sacrifices some accuracy for speed. The original approach’s implementation has been improved by using good programming practice. These improvements increased run-time performance by a constant factor of approximately 2 and reduced memory requirements by a constant factor of approximately 6. These search strategies allow multithreading to better use modern CPU hardware. PFAM data of 2000–30,000 taxa were used for testing performance. The canonical implementation with three threads improved average performance by approximately 2.1. The relaxed search has good quality, and the accuracy was tested on a mammal and a eukaryote data set. Kendall tau distance was used as a rough measure of topological similarity for the relaxed and canonical search strategies.
Detecting archaic introgression without archaic reference genomes
Authors: Skov Laurits , Hui Ruoyun , Hobolth Asger , Scally Aylwyn , Schierup Mikkel Heide , Durbin Richard
Published: March 2018

Human populations out of Africa have experienced at least two bouts of introgression from archaic humans, from Neanderthals and Denisovans. In Papuans there is prior evidence of both these introgressions. Here we present a new approach to detect segments of individual genomes of archaic origin without using an archaic reference genome. The approach is based on a hidden Markov model that identifies genomic regions with a high density of single nucleotide variants (SNVs) not seen in unadmixed populations. We show using simulations that this provides a powerful approach to identifying segments of archaic introgression with a small rate of false detection. Furthermore our approach is able to accurately infer admixture proportions and divergence time of human and archaic populations.

We apply the model to detect archaic introgression in 89 Papuans and show how the identified segments can be assigned to likely Neanderthal or Denisovan origin. We report more Denisovan admixture than previous studies and directly find a shift in size distribution of fragments of Neanderthal and Denisovan origin that is compatible with a difference in admixture time. Furthermore, we identify small amounts of Denisova ancestry in West Eurasians, South East Asians and South Asians.
P-bodies and the miRNA pathway regulate translational repression ofbicoidmRNA duringDrosophila melanogasteroogenesis
Authors: McLaughlin John M. , Smith Daniel F.Q. , Catrina Irina E. , Bratu Diana P.
Published: March 2018

Embryonic axis patterning inDrosophila melanogasteris partly achieved by mRNAs that are maternally localized to the oocyte; the spatio-temporal regulation of these transcripts’ stability and translation is a characteristic feature of oogenesis. While protein regulatory factors are necessary for the translational regulation of some maternal transcripts (e.g.oskarandgurken), small RNA pathways are also known to regulate mRNA stability and translation in eukaryotes. MicroRNAs (miRNAs) are small RNA regulators of gene expression, widely conserved throughout eukaryotic genomes and essential for animal development. The mainD. melanogasteranterior determinant,bicoid, is maternally transcribed, but it is not translated until early embryogenesis. We investigated the possibility that its translational repression during oogenesis is mediated by miRNA activity. We found that thebicoid3’UTR contains a highly conserved, predicted binding site for miR-305. Our studies reveal that miR-305 regulates the translation of a reporter gene containing thebicoid3’UTR in cell culture, and that miR-305 only partially contributes tobicoidmRNA translational repression during oogenesis. We also found that Processing bodies (P-bodies) in the egg chamber may play a role in stabilizingbicoidand other maternal transcripts. Here, we offer insights into the possible role of P-bodies and the miRNA pathway in the translational repression ofbicoidmRNA during oogenesis.
Selection in parental species predicts hybrid evolution
Authors: Runemark Anna , Bailey Richard I , Bache-Mathiesen Lena , Sætre Glenn-Peter
Published: March 2018

While hybridization is recognized as important in evolution, its contribution to adaptation and diversification remains poorly understood. Using genomically diverged island populations of the homoploid hybrid Italian sparrow, we test predictions for phenotypic trait values and evolvability based on patterns of parental species divergence in four plumage color traits. We find associations between parental divergence and trait evolution in Italian sparrows. Fixed major QTL in species differences lead to hybrids with higher trait variation, and hence evolvability, than the parent species. Back and crown plumage show no correlation between current within-parent variability and among-parent differentiation. For these traits, Italian sparrow phenotypes are biased towards axes of high parental differentiation and show greater phenotypic novelty along axes of low current parental evolvability, as predicted when major QTL are involved in species differences. Crown color has consistently evolved back towards one parent, while back color varies among islands. We also find significant among-population diversification within the Italian sparrow. Hence, hybridization of the same parent species can generate different phenotypes. In conclusion, we find support for parental phenotypic divergence patterns reflecting divergence mechanisms, and hence such patterns can be useful in predicting how hybridization alters the potential to evolve and adapt.
Nucleosome remodelling at origins of Global Genome-Nucleotide Excision Repair occurs at the boundaries of higher-order chromatin structure
Authors: van Eijk Patrick , Nandi Shuvro Prokash , Yu Shirong , Bennett Mark , Leadbitter Matthew , Teng Yumin , Reed Simon H.
Published: March 2018

Repair of UV-induced DNA damage requires chromatin remodeling. How repair is initiated in chromatin remains largely unknown. We recently demonstrated that Global Genome Nucleotide Excision Repair (GG-NER) in chromatin is organized into domains around open reading frames. Here, we identify these domains, and by examining DNA damage-induced changes in the linear structure of nucleosomes, we demonstrate how chromatin remodeling is initiated during repair. In undamaged cells, we show that the GG-NER complex occupies chromatin at nucleosome free regions of specific gene promoters. This establishes the nucleosome structure at these genomic locations, which we refer to as GG-NER complex binding sites (GCBS’s). We demonstrate that these sites are frequently located at genomic boundaries that delineate chromasomally interacting domains (CIDs). These boundaries define domains of higher-order nucleosome-nucleosome interaction. We show that efficient repair of DNA damage in chromatin is initiated following disruption of H2A.Z-containing nucleosomes adjacent to GCBSs by the GG-NER complex.
Long-read genome sequence and assembly ofLeptopilina boulardi: a specialistDrosophilaparasitoid
Authors: Khan Shagufta , Sowpati Divya Tej , Mishra Rakesh K
Published: March 2018

Background

Leptopilina boulardiis a specialist parasitoid belonging to the order Hymenoptera, which attacks the larval stages ofDrosophila. TheLeptopilinagenus has enormous value in the biological control of pests as well as in understanding several aspects of host-parasitoid biology. However, none of the members of Figitidae family has their genomes sequenced. In order to improve the understanding of the parasitoid wasps by generating genomic resources, we sequenced the whole genome ofL. boulardi.

Findings

Here, we report a high-quality genome ofL. boulardi, assembled from 70Gb of Illumina reads and 10.5Gb of PacBio reads, forming a total coverage of 230X. The 375Mb draft genome has an N50 of 275Kb with 6315 scaffolds >500bp, and encompasses >95% complete BUSCOs. The GC% of the genome is 28.26%, and RepeatMasker identified 868105 repeat elements covering 43.9% of the assembly. A total of 25259 protein-coding genes were predicted using a combination ofab-initioand RNA-Seq based methods, with an average gene size of 3.9Kb. 78.11% of the predicted genes could be annotated with at least one function.

Conclusion

Our study provides a highly reliable assembly of this parasitoid wasp, which will be a valuable resource to researchers studying parasitoids. In particular, it can help delineate the host-parasitoid mechanisms that are part of theDrosophila–Leptopilinamodel system.
Compound signaling activates endogenous retroviruses by inducing enhancer and gene-neighborhood transcription
Authors: Azébi Saliha , Batsché Eric , Michel Fréderique , Kornobis Etienne , Muchardt Christian
Published: March 2018

Multiple sclerosis (MS) is a neuroinflammatory and autoimmune disease, in which various immune cell types and autoreactive T cells exert a pathogenic activity. This disease is also associated with increased transcription of several endogenous retroviruses (HERVs) normally kept in check by heterochromatin. Here, we have uncovered an organic pollutant dieldrin that activates several HERVs associated with MS and allowing us to examine the mechanism of their activation. Dieldrin singles out by its ability to simultaneously activate the MAP kinase and the PI3K pathways, while also triggering calcium dependent peptidylarginine deiminase activity. It was this association of pathways that caused HERV activation, a phenomenon that was only part of more generally increased transcription of heterochromatic regions. The HERV transcripts were generally not polyadenylated. Some arose as a consequence of activation of HERV-based enhancers, while others were the result of unusually strong activation at some mostly transcription factor genes causing transcription to leak out of the HERV-free region that surrounds them. Altogether, our data emphasized the hazard associated with simultaneous activation of multiples signaling pathways by xenobiotics, while also providing a very general toolbox for the interpretation of HERV transcription.
Wild-type and cancer-related p53 proteins are preferentially degraded by MDM2 as dimers rather than tetramers
Authors: Katz Chen , Low-Calle Ana Maria , Choe Joshua H. , Laptenko Oleg , Tong David , Joseph-Chowdhury Jazmine-Saskya N. , Garofalo Francesca , Zhu Yan , Friedler Assaf , Prives Carol
Published: March 2018

The p53 tumor suppressor protein is the most well studied as a regulator of transcription in the nucleus, where it exists primarily as a tetramer. However, there are other oligomeric states of p53 that are relevant to its regulation and activities. In unstressed cells, p53 is normally held in check by MDM2 that targets p53 for transcriptional repression, proteasomal degradation, and cytoplasmic localization. Here we discovered a hydrophobic region within the MDM2 N-terminal domain that binds exclusively to the dimeric form of the p53 C-terminal domain in vitro. In cell-based assays, MDM2 exhibits superior binding to, hyperdegradation of, and increased nuclear exclusion of dimeric p53 when compared with tetrameric wild-type p53. Correspondingly, impairing the hydrophobicity of the newly identified N-terminal MDM2 region leads to p53 stabilization. Interestingly, we found that dimeric mutant p53 is partially unfolded and is a target for ubiquitin-independent degradation by the 20S proteasome. Finally, forcing certain tumor-derived mutant forms of p53 into dimer configuration results in hyperdegradation of mutant p53 and inhibition of p53-mediated cancer cell migration. Gaining insight into different oligomeric forms of p53 may provide novel approaches to cancer therapy.
Modeling and verification of the equivalent circuit for high temperature superconducting partial-core transformer with ReBCO-coated conductors
Authors: Hu Daoyu , Zhang Jianwen , Gu Feng , Li Zhuyong
Published: March 2018

Purpose

The purpose of this study is to propose a modeling method of the equivalent circuit for a new type of high-temperature superconducting partial-core transformer (HTS-PCT) made of ReBCO-coated conductors.

Design/methodology/approach

The modeling process is based on the “Steinmetz” equivalent circuit. The impedance components in the circuit are obtained by the calculations of the core losses and AC losses of the HTS windings by using theoretical methods. An iterative computation is also used to decide the equivalent resistances of the AC losses of the primary and secondary HTS windings. The reactance components in the circuit are calculated from the energy stored in the magnetic fields by finite element method. The validation of the modeling method is verified by experimental results

Findings

The modeling method of the equivalent circuit of HTS-PCT is valid, and an equivalent circuit for HTS-PCT is presented.

Practical implications

The equivalent circuit of HTS-PCT could be obtained by the suggested modeling method. Then, it is easy to analyze the characteristics of the HTS-PCT by its equivalent circuit. Moreover, the modeling method could also be useful for the design of a specific HTS-PCT.

Originality/value

The study proposes a modeling method of the HTS-PCT made of the second-generation HTS tapes, i.e. ReBCO-coated conductors.
Modeling and simulation of saturated double rotor induction machine
Authors: Choobdari Omran Koosha , Mosallanejad Ali
Published: March 2018

Purpose

Double rotor induction machine (DRIM) is a particular type of induction machine (IM) that has been introduced to improve the parameters of the conventional IM. The purpose of this study is to propose a dynamic model of the DRIM under saturated and unsaturated conditions by using the equations obtained in this paper. Also, skin and temperature effects are considered in this model.

Design/methodology/approach

First, the DRIM structure and its performance will be briefly reviewed. Then, to realize the DRIM model, the mathematical equations of the electrical and mechanical part of the DRIM will be presented by state equations in the q-d axis by using the Park transformation. In this paper, the magnetizing fluxes saturation is included in the DRIM model by considering the difference between the amplitudes of the unsaturated and saturated magnetizing fluxes. The skin and temperature effects are also considered in this model by correcting the rotor and stator resistances values during operation.

Findings

To evaluate the effects of the saturation and skin effects on DRIM performance and validate the model, the machine is simulated with/without consideration of saturation and skin effects by the proposed model. Then, the results, including torque, speed, stator and rotor currents, active and reactive power, efficiency, power factor and torque-speed characteristic, are compared. In addition, the performance of the DRIM has been investigated at different speed conditions and load variations. The proposed model is developed in Matlab/Simulink for the sake of validation.

Originality/value

This paper presents an understandable model of DRIM with and without saturation, which can be used to analyze the steady-state and transient behavior of the motor in different situations.
Miniaturized quad-band coplanar-fed monopole antenna for tablet computers
Authors: Subbaraj Sangeetha , Kanagasabai Malathi , Mohammed Gulam Nabi Alsath , Panneer Selvam Yogeshwari , Kingsly Saffrine , Yeragudipati Venkata Ramana Rao
Published: March 2018

Purpose

This paper aims to present the design of a compact quad-band coplanar-fed monopole antenna for tablet computer applications.

Design/methodology/approach

The antenna has the smallest size of 26 × 14 mm and supports GSM, Wi-Fi, WIMAX and Bluetooth. The proposed antenna consists of a coplanar fed main radiator, c-shaped stubs and parasitic meandered stub. The inverted c-shaped stubs enhance the bandwidth of upper frequencies. The resonance at 2.4 GHz is individually controlled by the coupled meandered stub.

Findings

The percentage bandwidth in the four operating bands are 8.7/4.12/27.8/13.3%. Furthermore, the antenna is integrated with the mock-up ground plane and specific absorption rate (SAR) calculations are performed. The estimated SAR is less than 1.6 W/kg for a 1 g body tissue. The gain and efficiency of the antenna are 3.56/4.37/4.97/6 dBi and 82.4/85/97.1/89.3%, respectively. The measured impedance and radiation characteristics of the fabricated prototype are in good correlation with the simulated results.

Originality/value

In the proposed work, vias and lumped elements are not used for lower band excitation, and most of the wireless applications in the tablet computers have been covered. Further, the effect of antenna with different orientation has been tested for the estimation of SAR.
Measurements show need for transformer core joint details in finite element modelling of GIC and DC effects
Authors: Chisepo Hilary Kudzai , Borrill Leslie David , Gaunt Charles Trevor
Published: March 2018

Purpose

This paper aims to improve the finite element modelling of transformers subjected to DC excitation, by including core joint details.

Design/methodology/approach

Geomagnetically induced currents (GICs) or leakage DC can cause part-cycle, half wave saturation of a power transformer’s core. Practical measurements and finite element matrix (FEM) simulation were carried out using three laboratory-scale, untanked single-phase four limb transformers resembling real power transformers in terms of the core steel and parallel winding assemblies. “Equivalent air gaps” at the joints, based on AC measurements, were applied to the FEM models for simultaneous AC and DC excitation.

Findings

Measurements confirm that introducing equivalent air gaps at the joints improves the FEM simulation of transformers carrying DC.

Research limitations/implications

The FEM simulations based on the laboratory transformers are exemplary, showing the difference between modelling core joints as solid or including equivalent air gaps. They show that, for more representative results, laboratory transformers used for research should have mitred core joints (like power transformers).

Originality/value

This research shows why joint details are important in FEM models for analysing transformer core saturation in the presence of DC/GICs. Extending this, other core structures of power transformers with mitred joints should improve the understanding of the leakage flux during half-wave saturation.
Governance issues constraining the deployment of flood resilience strategies in Maroua, Far North Region of Cameroon
Authors: Wanie Clarkson Mvo , Ndi Roland Akoh
Published: March 2018

Purpose

Cities across the globe, particularly those of the less developed world, face long-term challenges associated with floods which impact negatively on the resilience of city systems and their inhabitants. In the city of Maroua, most urban management stakeholders have been unable to integrate flood resilience research into urban development issues. It is against this background that the purpose of this paper is to evaluate the governance issues constraining the deployment of flood resilience strategies implemented by residents in flood-prone zones and those used by the government via administrative authorities and institutions charged with urban development to flood-related risks in the city of Maroua, Far North Region of Cameroon.

Design/methodology/approach

Field surveys, participant observations, interviews, and on-the-spot appraisals were carried out with residents in flood-prone neighbourhoods and municipal authorities on the state of recurrent floods including mitigating strategies being implemented.

Findings

The results revealed that Maroua has a fragile ecological setting which has increased the vulnerability of the town to flood-related risks. This is further aggravated by the fact that municipal authorities are yet to have a thorough mastery of such recurrent flood incidences due to their limited planning horizons, rendering the urban poor disproportionately susceptible to flood-related stresses. This exposes them to unavoidable flood associated hazards such as water borne diseases (typhoid and cholera) as they are bogged down by physical and financial limitations. Besides, decision-making processes in relation to managing urban systems are not guided by good governance as efforts to enhance and integrate the local population for flood resilience are neither participatory nor inclusive, ushering the urban environment of Maroua into a frivolous path to profligacy.

Originality/value

For resilience to be deeply entrenched, the paper proffers for the mainstreaming of flood resilience strategies into urban development plans through multi-stakeholder involvement across different sectors and departments, as well as the setting up of a practical time table for monitoring the progress of these measures through geospatial technologies such as remote sensing and geographical information systems.
Development of a defect monitoring system (DMOSYS) for building maintenance at polytechnic
Authors: Bin Ismail Zul-Atfi
Published: March 2018

Purpose

The current maintenance management method has affected the efficiency of the building facility management at Polytechnics. Many issues such as poor service delivery, inadequate finance, poor maintenance planning and maintenance backlogs have emerged due to the usage of conventional method application (paper-based form and unsystematic database. The purpose of this paper is to review existing literature and case studies project of the technologies in maintenance management at Polytechnic, and subsequently to identify the challenge in improving the current maintenance management technologies.

Design/methodology/approach

The purpose of this paper is to review existing literature and case studies project of the technologies in maintenance management at Polytechnic, and subsequently to identify the challenges of information and communication technology (ICT) implementation for strategic defect diagnosis and decision-making in improving the current maintenance management technologies. Eight Polytechnics are selected on the basis of the major problems of using the conventional method in the comparison to investigate the maintenance management practices in each Polytechnic. There are around 32 Polytechnics in Malaysia and most are using conventional methods.

Findings

The findings reveal the need for a more sophisticated maintenance management system that provides guidelines for decision-making processes with the implementation of ICT. The interview results also reveal irregularities within the Malaysian Polytechnics’ maintenance management database. The system architecture and the information system prototype are presented to integrate the information database and maintenance management processes in improving the building diagnosis approach and decision-making process for managing building maintenance.

Originality/value

This new system is expected to become the successful technology in assisting the maintenance contractors, clients and developer for effective management of maintenance defects at Polytechnic.
The effect of culture on accounting conservatism during adoption of IFRS in the EU
Authors: Zeghal Daniel , Lahmar Zouhour
Published: March 2018

Purpose

This paper aims to examine the impact of culture on accounting conservatism during transition to international standards.

Design/methodology/approach

The sample used in this analysis consists of 15 countries of the European Union that have adopted International financial reporting standards (IFRS) pursuing Regulation N° 1606/2002. The study covers the 2000-2010 period. Two conservatism measures are used, the Basu (1997) measure to account for conditional conservatism and the accruals measure to account for unconditional conservatism. To test the impact of culture, the six dimensions of Hofstede (1980, 2010) are used.

Findings

The results of the analysis show that variation of conditional conservatism is influenced by the six cultural dimensions. However, unconditional conservatism is only affected by power distance.

Originality/value

The results of the study are interesting and provide a better understanding of the adoption of IFRS worldwide. The role of culture in explaining accounting practices after adopting a single set of accounting standards is particularly highlighted.
Control or chaos: impact of workarounds on internal controls
Authors: Pernsteiner Aimee , Drum Dawna , Revak Adam
Published: March 2018

Purpose

There have been many studies that investigated the causes of workarounds, but there is less research on their outcomes, such as the impact on internal control. This study aims to investigate the use of workarounds by a multinational organization that implemented SAP about 10 years ago, and how those workarounds affected internal controls.

Design/methodology/approach

A qualitative study is performed by analyzing interviews with company personnel for a multinational organization. Employees selected for interviews are primarily users of SAP’s accounting functions.

Findings

Workarounds have significant impacts on the internal controls over financial reporting. Workarounds cause compensating controls to be implemented, which are often manual in nature, and decrease the organizational efficiency and effectiveness.

Research limitations/implications

Workarounds become integrated into an organization’s activities to meet its business needs. This research raises questions to determine when maintaining organizational efficiency and control outweighs the need to provide customer service and other business needs.

Practical implications

Companies should consider whether their business processes can be modified to ensure that they can be handled within the enterprise system. In addition, the number of compensating controls required due to workarounds may decrease the organizational efficiency expected from having an enterprise resource planning system to ensure the integrity of financial information.

Originality/value

This paper moves beyond finding the causes of workarounds, and expands what is known about workarounds and their impact on an organization. An important contribution of this study is to consider the intersection of workarounds, ERP systems and internal controls.
Knowledge exchange in the UK CLAHRCs
Authors: Racko Girts
Published: March 2018

Purpose

The purpose of this paper is to examine how knowledge exchange between academics and clinicians in Collaborations for Leadership in Applied Health Research and Care (CLAHRCs) is influenced by their social position based on their symbolic and social capitals, that is, their personal professional status and connections to high-status professional peers, knowledge brokers, and unfamiliar professional peers.

Design/methodology/approach

Using an online survey, the author triangulates the cross-sectional measurement of the effects of academic and clinicians’ social position in the initial and later phases of CLAHRCs with the longitudinal measurement of these effects over a two-year period.

Findings

First, academics and clinicians with a higher personal professional status are more likely to develop joint networks and decision making both in the early and later phases of a CLAHRC. Second, academics and clinicians who are more connected to higher status occupational peers are more likely to develop joint networks in the early phase of a knowledge exchange partnership but are less likely to become engaged in joint networks over time. Third, involvement of knowledge brokers in the networks of academics and clinicians is likely to facilitate their inter-professional networking only in the later partnership phase.

Practical implications

Academics and clinicians’ capitals have a distinctive influence on knowledge exchange in the early and later phases of CLAHRCs and on a change in knowledge exchange over a two-year period.

Originality/value

Prior research on CLAHRCs has examined how knowledge exchange between academics and clinicians can be encouraged by the creation of shared governance mechanisms. The author advances this research by highlighting the role of their social position in facilitating knowledge exchange.
The hybridising of financial and service expertise in English local authority budget control
Authors: Ahrens Thomas , Ferry Laurence , Khalifa Rihab
Published: March 2018

Purpose

This paper aims to trace the hybridising of financial and service expertise in English local authority budget control to provide a more comprehensive understanding of the contexts that gave rise to hybridisation than do previous accountability research frameworks.

Design/methodology/approach

Using practice theory, this paper interprets the findings from a field study of Newcastle City Council and a review of relevant local authority regulation for England, stretching back to the 1980s.

Findings

The hybridisation of financial and service expertise has entailed major changes to the practices on which local authority management depends, fuelled by a changing societal role of local authorities. Frequently, local authorities are no longer providers of public services but enablers who purchase services and manage arms-length contracts. This paper identifies some of the ways in which three structural elements that underpin local authority management practices have evolved to give rise to novel practices.

Research limitations/implications

Even though this paper’s research into changing regulatory frameworks, rules and evolving local authority financial practices is based on institutional changes in England since the 1980s, the fieldwork element which fleshes out certain implications for local authority practices has focused on Newcastle City Council. Future research could fruitfully examine these issues in other local authorities.

Practical implications

The hybridisation of financial and service expertise has contributed to reshaping local government beyond the rules that are put in place for regulating the sector by giving rise to new practices. Recent key developments include new service delivery arrangements, for example, through council-owned subsidiaries or third-sector organisations. It is important that, in an austerity context, new risks to “off the books” service quality is matched by new control and audit arrangements. Moreover, the professional bodies that service local government should recognise the new forms of hybridisation of finance and service expertise and ensure arrangements for the changing skill sets of those involved in service provision.

Originality/value

This is the first paper to analyse the emergence of hybrid financial expertise in the public sector with reference to distinct structural elements of the relevant practices.
Disparities and Divided Growth: Ethnic Entrepreneurship in the Greater Los Angeles Area, 1980–2015
Authors: Wang Qingfang
Published: March 2018

This study employs a multilevel research design to examine business ownership across ethnic groups in the greater Los Angeles area. It finds significant divide between white and non‐white businesses along the labor market hierarchy. The entrepreneurial environment, ethnic residential communities, ethnic business spatial clustering, ethnic concentration in particular niche sectors, and ethnic diversity in local areas are all related to business ownership and disparities across ethnic groups. The results suggest that ethnically diverse neighborhoods and co‐ethnic business communities could provide a conducive institutional environment and resources for minority businesses to start. However, in contrast to white owned businesses, ethnic minority businesses' concentration in the low‐end and easy‐entry sectors may reinforce their disadvantages and hinder upward economic mobility. This study provides policy implications for community regional development through entrepreneurship especially when race and ethnicity are concerned.
Recent Decrease of Regional Disparity within Thailand
Authors: Nozaki Kenji
Published: March 2018

The existence of wage gaps between Thailand and its neighboring countries facilitate the division of labor in manufacturing production in the GMS. However, if the wage gap inside Thailand is too large, such effect is diminished. Under such recognition, this paper aims to clarify the recent situation of the regional disparity in Thailand.The author acquired three findings. Firstly, the regional GINI coefficient in Thailand is confirmed to match Kuznets’ inverted U-shaped curve. The analysis shows that the peak of the disparity occurred with income level in the early to mid-1990s. Secondly, the recent decrease of the disparity is partly explained by the changes in industrial policies. Export promotion policies introduced after import substitution in mid-1980s relocated the manufacturing production bases. It was followed by other supporting industries. They increased the income level of remote areas, and it caused the decrease of the regional disparity. Finally, the author found that the case of Thailand is different from the case of Indonesia. Even though Indonesia is also growing with foreign direct investment like Thailand, no Kuznets’ U-shaped curve of regional disparity was observed.