bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing cognitive load attenuates right arm swing in healthy human walking
Authors: Killeen Tim , Easthope Christopher S. , Filli Linard , Lőrincz Lilla , Schrafl-Altermatt Miriam , Brugger Peter , Linnebank Michael , Curt Armin , Zörner Björn , Bolliger Marc
Published: January 2017

Human arm swing looks and feels highly automated, yet it is increasingly apparent that higher centres, including the cortex, are involved in many aspects of locomotor control. The addition of a cognitive task increases arm swing asymmetry during walking, but the characteristics and mechanism of this asymmetry are unclear. We hypothesized that this effect is lateralized and a Stroop word-colour naming task—primarily involving left hemisphere structures—would reduce right arm swing only. We recorded gait in 83 healthy subjects aged 18–80 walking normally on a treadmill and while performing a congruent and incongruent Stroop task. The primary measure of arm swing asymmetry—an index based on both three-dimensional wrist trajectories in which positive values indicate proportionally smaller movements on the right—increased significantly under dual-task conditions in those aged 40–59 and further still in the over-60s, driven by reduced right arm flexion. Right arm swing attenuation appears to be the norm in humans performing a locomotor-cognitive dual-task, confirming a prominent role of the brain in locomotor behaviour. Women under 60 are surprisingly resistant to this effect, revealing unexpected gender differences atop the hierarchical chain of locomotor control.
Origin of the scaling laws of sediment transport
Authors: Ali Sk Zeeshan , Dey Subhasish
Published: January 2017

In this paper, we discover the origin of the scaling laws of sediment transport under turbulent flow over a sediment bed, for the first time, from the perspective of the phenomenological theory of turbulence. The results reveal that for the incipient motion of sediment particles, the densimetric Froude number obeys the ‘(1 + 
σ
)/4’ scaling law with the relative roughness (ratio of particle diameter to approach flow depth), where
σ
is the spectral exponent of turbulent energy spectrum. However, for the bedforms, the densimetric Froude number obeys a ‘(1 + 
σ
)/6’ scaling law with the relative roughness in the enstrophy inertial range and the energy inertial range. For the bedload flux, the bedload transport intensity obeys the ‘3/2’ and ‘(1 + 
σ
)/4’ scaling laws with the transport stage parameter and the relative roughness, respectively. For the suspended load flux, the non-dimensional suspended sediment concentration obeys the ‘

−

Z

’ scaling law with the non-dimensional vertical distance within the wall shear layer, where

Z

is the Rouse number. For the scour in contracted streams, the non-dimensional scour depth obeys the ‘4/(3 − 
σ
)’, ‘−4/(3 − 
σ
)’ and ‘−(1 + 
σ
)/(3 − 
σ
)’ scaling laws with the densimetric Froude number, the channel contraction ratio (ratio of contracted channel width to approach channel width) and the relative roughness, respectively.
Protection of large predators in a marine reserve alters size-dependent prey mortality
Authors: Selden Rebecca L. , Gaines Steven D. , Hamilton Scott L. , Warner Robert R.
Published: January 2017

Where predator–prey interactions are size-dependent, reductions in predator size owing to fishing has the potential to disrupt the ecological role of top predators in marine ecosystems. In southern California kelp forests, we investigated the size-dependence of the interaction between herbivorous sea urchins and one of their predators, California sheephead (
Semicossyphus pulcher
). Empirical tests examined how differences in predator size structure between reserve and fished areas affected size-specific urchin mortality. Sites inside marine reserves had greater sheephead size and biomass, while empirical feeding trials indicated that larger sheephead were required to successfully consume urchins of increasing test diameter. Evaluations of the selectivity of sheephead for two urchin species indicated that shorter-spined purple urchins were attacked more frequently and successfully than longer-spined red urchins of the same size class, particularly at the largest test diameters. As a result of these size-specific interactions and the higher biomass of large sheephead inside reserves, urchin mortality rates were three times higher inside the reserve for both species. In addition, urchin mortality rates decreased with urchin size, and very few large urchins were successfully consumed in fished areas. The truncation of sheephead size structure that commonly occurs owing to fishing will probably result in reductions in urchin mortality, which may reduce the resilience of kelp beds to urchin barren formation. By contrast, the recovery of predator size structure in marine reserves may restore this resilience, but may be delayed until fish grow to sizes capable of consuming larger urchins.
Intra- and intersexual differences in parasite resistance and female fitness tolerance in a polymorphic insect
Authors: Willink Beatriz , Svensson Erik I.
Published: January 2017

To understand host–parasite interactions, it is necessary to quantify variation and covariation in defence traits. We quantified parasite resistance and fitness tolerance of a polymorphic damselfly (
Ischnura elegans
), an insect with three discrete female colour morphs but with monomorphic males. We quantified sex and morph differences in parasite resistance (prevalence and intensity of water mite infections) and morph-specific fitness tolerance in the females in natural populations for over a decade. There was no evidence for higher parasite susceptibility in males as a cost of sexual selection, whereas differences in defence mechanisms between female morphs are consistent with correlational selection operating on combinations of parasite resistance and tolerance. We suggest that tolerance differences between female morphs interact with frequency-dependent sexual conflict, which maintains the polymorphism locally. Host–parasite interactions can therefore shape intra- and intersexual phenotypic divergence and interfere with sexual selection and sexual conflict.
Trade-off between carotenoid-based sexual ornamentation and sperm resistance to oxidative challenge
Authors: Tomášek Oldřich , Albrechtová Jana , Němcová Martina , Opatová Pavlína , Albrecht Tomáš
Published: January 2017

It has been hypothesized that carotenoid-based sexual ornamentation signals male fertility and sperm competitive ability as both ornamentation and sperm traits may be co-affected by oxidative stress, resulting in positive covariation (the ‘redox-based phenotype-linked fertility hypothesis’; redox-based PLFH). On the other hand, the ‘sperm competition theory’ (SCT) predicts a trade-off between precopulatory and postcopulatory traits. Here, we manipulate oxidative status (using diquat dibromide) and carotenoid availability in adult zebra finch (Taeniopygia guttata) males in order to test whether carotenoid-based beak ornamentation signals, or is traded off against, sperm resistance to oxidative challenge. Initial beak colouration, but not its change during the experiment, was associated with effect of oxidative challenge on sperm velocity, such that more intense colouration predicted an increase in sperm velocity under control conditions but a decline under oxidative challenge. This suggests a long-term trade-off between ornament expression and sperm resistance to oxidative challenge. Shortening of the sperm midpiece following oxidative challenge further suggests that redox homeostasis may constrain sperm morphometry. Carotenoid supplementation resulted in fewer sperm abnormalities but had no effect on other sperm traits. Overall, our data challenge the redox-based PLFH, partially support the SCT and highlight the importance of carotenoids for normal sperm morphology.
Species decline under nitrogen fertilization increases community-level competence of fungal diseases
Authors: Liu Xiang , Lyu Shengman , Sun Dexin , Bradshaw Corey J. A. , Zhou Shurong
Published: January 2017

The artificial fertilization of soils can alter the structure of natural plant communities and exacerbate pathogen emergence and transmission. Although the direct effects of fertilization on disease resistance in plants have received some research attention, its indirect effects of altered community structure on the severity of fungal disease infection remain largely uninvestigated. We designed manipulation experiments in natural assemblages of Tibetan alpine meadow vegetation along a nitrogen-fertilization gradient over 5 years to compare the relative importance of direct and indirect effects of fertilization on foliar fungal infections at the community level. We found that species with lower proneness to pathogens were more likely to be extirpated following fertilization, such that community-level competence of disease, and thus community pathogen load, increased with the intensity of fertilization. The amount of nitrogen added (direct effect) and community disease competence (indirect effect) provided the most parsimonious combination of parameters explaining the variation in disease severity. Our experiment provides a mechanistic explanation for the dilution effect in fertilized, natural assemblages in a highly specific pathogen–host system, and thus insights into the consequences of human ecosystem modifications on the dynamics of infectious diseases.
Literature Consistency of Bioinformatics Sequence Databases is Effective for Assessing Record Quality
Authors: Bouadjenek Mohamed Reda , Verspoor Karin , Zobel Justin
Published: January 2017

Bioinformatics sequence databases such as Genbank or UniProt contain hundreds of millions of records of genomic data. These records are derived from direct submissions from individual laboratories, as well as from bulk submissions from large-scale sequencing centres; their diversity and scale means that they suffer from a range of data quality issues including errors, discrepancies, redundancies, ambiguities, incompleteness, and inconsistencies with the published literature. In this work, we seek to investigate and analyze the data quality of sequence databases from the perspective of a curator, who must detect anomalous and suspicious records.

Specifically, we emphasize the detection of inconsistent records with respect to the literature. Focusing on GenBank, we propose a set of 24 quality indicators, which are based on treating a record as a query into the published literature, and then use query quality predictors. We then carry out an analysis that shows that the proposed quality indicators and the quality of the records have a mutual relationship, in which one depends on the other. We propose to represent record-literature consistency as a vector of these quality indicators. By reducing the dimensionality of this representation for visualization purposes using Principal Component Analysis, we show that records which have been reported as inconsistent with the literature fall roughly in the same area, and therefore share similar characteristics. By manually analyzing records not previously known to be erroneous that fall in the same area than records know to be inconsistent, we show that 1 record out of 4 is inconsistent with respect to the literature. This high density of inconsistent record opens the way towards the development of automatic methods for the detection of faulty records. We conclude that literature inconsistency is a meaningful strategy for identifying suspicious records.
An analytic approach for interpretable predictive models in high dimensional data, in the presence of interactions with exposures
Authors: Bhatnagar Sahir Rai , Yang Yi , Khundrakpam Budhachandra , Evans Alan C , Blanchette Mathieu , Bouchard Luigi , Greenwood Celia MT
Published: January 2017

Predicting a phenotype and understanding which variables improve that prediction are two very challenging and overlapping problems in analysis of high-dimensional data such as those arising from genomic and brain imaging studies. It is often believed that the number of truly important predictors is small relative to the total number of variables, making computational approaches to variable selection and dimension reduction extremely important. To reduce dimensionality, commonly-used two-step methods first cluster the data in some way, and build models using cluster summaries to predict the phenotype.

It is known that important exposure variables can alter correlation patterns between clusters of high-dimensional variables, i.e., alter network properties of the variables. However, it is not well understood whether such altered clustering is informative in prediction. Here, assuming there is a binary exposure with such network-altering effects, we explore whether use of exposure-dependent clustering relationships in dimension reduction can improve predictive modelling in a two-step framework. Hence, we propose a modelling framework called ECLUST to test this hypothesis, and evaluate its performance through extensive simulations.

With ECLUST, we found improved prediction and variable selection performance compared to methods that do not consider the environment in the clustering step, or to methods that use the original data as features. We further illustrate this modelling framework through the analysis of three data sets from very different fields, each with high dimensional data, a binary exposure, and a phenotype of interest. Our method is available in theeclustCRAN package.
Infectious Reactivation of Cytomegalovirus Explaining Age- and Sex-Specific Patterns of Seroprevalence
Authors: Boven Michiel van , Kassteele Jan van de , Korndewal Marjolein J. , van Dorp Christiaan H. , Kretzschmar Mirjam , der Klis Fiona van , de Melker Hester E. , Vossen Ann C. , Baarle Debbie van
Published: January 2017

Human cytomegalovirus is a herpes virus with poorly understood transmission dynamics. We here provide quantitative estimates of the transmissibility of primary infection, reactivation, and re-infection using age-and sex-specific antibody response data. The data are optimally described by three distributions of antibody measurements, i.e. uninfected, infected, and infected after reactivation/re-infection. Estimates of seroprevalence increase gradually with age, such that at 80 years 73% (95%CrI: 64%-78%) of females and 62% (95%CrI: 55%-68%) of males is infected, while 57% (95%CrI: 47%-67%) of females and 37% (95%CrI: 28%-46%) of males has experienced a reactivation or re-infection episode. Merging the statistical analyses with transmission models, we find that infectious reactivation is key to provide a good fit fit to the data. Estimated reactivation rates increase from low values in children to 2%-6% per year older women. The results advance a hypothesis in which adult-to-adult transmission after infectious reactivation is the main driver of infection.
The circadian dynamics of small nucleolar RNA
Authors: Aitken Stuart , Semple Colin A.
Published: January 2017

The circadian regulation of gene expression allows plants and animals to anticipate predictable environmental changes. While the influence of the circadian clock has recently been shown to extend to ribosome biogenesis, the dynamics and regulation of the many small nucleolar RNA that are required in pre-ribosomal RNA folding and modification are unknown. Using a novel computational method, we show that 18S and 28S pre-rRNA are subject to circadian regulation in a nuclear RNA sequencing time course. A population of snoRNA with circadian expression is identified that is functionally associated with rRNA modification. More generally, we find the abundance of snoRNA known to modify 18S and 28S to be inversely correlated with the abundance of their target. Cyclic patterns in the expression of a number of snoRNA indicate a coordination with rRNA maturation, potentially through an upregulation in their biogenesis, or their release from mature rRNA at the end of the previous cycle of rRNA maturation, in antiphase with the diurnal peak in pre-rRNA. Few cyclic snoRNA have cyclic host genes, indicating the action of regulatory mechanisms in addition to transcriptional activation of the host gene. For highly-expressed independently transcribed snoRNA, we find a characteristic RNA polymerase II and H3K4me3 signature that correlates with mean snoRNA expression over the day.
Elucidating interplay of speed and accuracy in biological error correction
Authors: Banerjee Kinshuk , Kolomeisky Anatoly B. , Igoshin Oleg A.
Published: January 2017

One of the most fascinating features of biological systems is the ability to sustain high accuracy of all major cellular processes despite the stochastic nature of underlying chemical processes. It is widely believed that such low errors are the result of the error correcting mechanism known as kinetic proofreading. However, it is usually argued that enhancing the accuracy should result in slowing down the process leading to so-called speed-accuracy trade-off. We developed a discrete-state stochastic framework that allowed us to investigate the mechanisms of the proofreading using the method of first-passage processes. With this framework, we simultaneously analyzed speed and accuracy of the two fundamental biological processes, DNA replication and tRNA selection during the translation. The results indicate that speed-accuracy trade-off is not always observed. However, when the trade-off is present, the biological systems tend to optimize the speed rather than the accuracy of the processes, as long as the error level is tolerable. Additional constraints due to the energetic cost of proofreading also play a role in the error correcting process. Our theoretical findings provide a new microscopic picture of how complex biological processes are able to function so fast with a high accuracy.
Photorelease of Diacylglycerol Increases the Amplitude and Duration of Protein Kinase C-BetaII Relocationin cyto
Authors: Goedhart Joachim , Gadella Theodorus W.J.
Published: January 2017

Diacylglycerol (DAG) is a lipid second messenger produced by receptor stimulated phospholipase C and is capable of activating several PKC isoforms. Classical PKC isoforms require simultaneous presence of calcium and DAG for activation and relocation to membranes. The aim of this study was to synthesize a photolabile precursor of DAG and examine the effect of an immediate increase of the signaling lipid on PKC relocation. Caged DAG was synthesized using a photoreleasable 7-diethyl-aminocoumarin (DEACM) group. Photolysis was monitoredin vitroby an increase in coumarin fluorescence from which an uncaging quantum yield of 1.1% was determined. This quantum yield proved ideal for efficient uncaging at high UV power while allowing localization of the fluorescent compound at low UV power. Taking advantage of the coumarin fluorescence, it was demonstrated that DEACM-DiC8 accumulated inside cells. Effects of DAG photorelease on periodic relocations of PKCbetaII, induced by histamine, UTP or EGF, were studied. Photorelease of DAGin cytoimmediately increased the amplitude and duration of relocation events, regardless of the agonist used. Together, the results demonstrate the usefulness of caged DAG for dissecting PKC signaling and suggest that DAG levels are limiting during signaling.
Mass-spectrometry of single mammalian cells quantifies proteome heterogeneity during cell differentiation
Authors: Budnik Bogdan , Levy Ezra , Harmange Guillaume , Slavov Nikolai
Published: January 2017

Cellular heterogeneity is important to biological processes, including cancer and development. However, proteome heterogeneity is largely unexplored because of the limitations of existing methods for quantifying protein levels in single cells. To alleviate these limitations, we developed Single Cell ProtEomics by Mass Spectrometry (SCoPE-MS), and validated its ability to identify distinct human cancer cell types based on their proteomes. We used SCoPE-MS to quantify over a thousand proteins in differentiating mouse embryonic stem (ES) cells. The single-cell proteomes enabled us to deconstruct cell populations and infer protein abundance relationships. Comparison between single-cell proteomes and transcriptomes indicated coordinated mRNA and protein covariation. Yet many genes exhibited functionally concerted and distinct regulatory patterns at the mRNA and the protein levels, suggesting that post-transcriptional regulatory mechanisms contribute to proteome remodeling during lineage specification, especially for developmental genes. SCoPE-MS is broadly applicable to measuring proteome configurations of single cells and linking them to functional phenotypes, such as cell type and differentiation potentials.
PEAPODlimits developmental plasticity inArabidopsis
Authors: White Derek W. R.
Published: January 2017

Higher plants utilise developmental plasticity to adapt to changes in the environment, especially to variations in light. Much of this change in growth and development involves the light-mediated regulation of multiple hormone pathways. However, despite considerable progress towards understanding the molecular processes controlling light signalling and hormone activity, regulatory mechanisms preventing exaggerated plant developmental responses are not well understood. Here I report that thePPDregulatory complex has a crucial role in limiting developmental plasticity inArabidopsis. Reductions inPPDorKIX8/9gene expression resulted in; tolerance to ABA inhibition of seed germination, hypocotyl elongation, increases in stomata on hypocotyls, cambial cell proliferation and seed weight, and delayed flowering. Transcript profiling and analyses of hormone responses and genetic interactions established PPD modulates developmental plasticity, mainly by a combination of transcriptional activation and repression of genes controlling CRY/PHY light signalling and ABA, auxin, brassinosteroid, cytokinin and gibberellin homeostasis.
UK university policy approaches towards the copyright ownership of scholarly works and the future of open access
Authors: Gadd Elizabeth
Published: January 2017

Purpose

The purpose of this paper is to consider how the open access policy environment has developed since the Rights Metadata for Open Archiving Project’s call in 2003 for universities and academics to assert joint copyright ownership of scholarly works and investigate whether UK universities are moving towards a joint copyright ownership.

Design/methodology/approach

The paper analyses 81 UK university copyright policies to understand what proportion make a claim over: IP ownership of all outputs; the copyright in scholarly works; re-using scholarly works in specific ways; and approaches to moral rights. Results are cross-tabulated by policy age and mission group.

Findings

Universities have not asserted their interest in scholarly works through joint ownership, leaving research funders and publishers to set open access policy. The paper finds an increased proportion of universities assert a generic claim to all IP (87 per cent) relative to earlier studies. In total, 74 per cent of policies relinquished rights in scholarly works in favour of academic staff; 20 per cent of policies share ownership of scholarly works through licensing; 28 per cent of policies assert the right to re-use scholarly works in some way; and 32 per cent of policies seek to protect moral rights. Policies that “share” ownership of scholarly works are more recent. The UK Scholarly Communication Licence (UK-SCL) should have an impact on this area. The reliance on individual academics to enforce a copyright policy or not to opt-out of the UK-SCL could be problematic. The paper concludes that open access may still be best served by joint ownership of scholarly works.

Originality/value

This the first large-scale analysis of UK university policy positions towards scholarly works. The paper discovers for the first time a move towards “shared” ownership of scholarly works in copyright policies.
Factors affecting usage of e-resources: scale development and validation
Authors: Garg Ruchi Jain , Kumar Vinod , Vandana
Published: January 2017

Purpose

The purpose of this paper is to develop and validate a scale involving the factors affecting usage of e-resources.

Design/methodology/approach

The present study identifies five factors affecting the usage of e-resources: training modes, awareness, influencers, utilitarian benefits, and experiential and hedonic benefits. To generate measurement items, two focus group discussions were carried out which resulted in 20 items. To empirically ensure reliability and validity of scale, data were collected from 347 postgraduate students actively using e-resources. To test reliability of scale, internal consistency reliability and construct reliability were examined. The construct validity of scale (which includes convergent validity and discriminant validity) was verified through confirmatory factor analysis using structure equation modeling.

Findings

Findings of the study present a statistically reliable and valid scale consisting of five factors and 18 items.

Originality/value

The present study is one of the distinctive studies on introducing a scale employing factors affecting usage of e-resources.
Tertiary students’ acceptance of a game to teach information literacy
Authors: Guo Yan Ru , Goh Dion Hoe-Lian , Luyt Brendan
Published: January 2017

Purpose

The purpose of this paper is to investigate tertiary students’ acceptance of digital game-based learning (DGBL). Specifically, it investigated the influence of learning motivation, enjoyment, and perceived usefulness on students’ behavioral intention to play an information literacy (IL) game.

Design/methodology/approach

In total, 150 tertiary students were recruited to play an IL game, and fill in a survey questionnaire. Multiple linear regression was performed.

Findings

Results indicated that attention, satisfaction, affective enjoyment, and perceived usefulness were significant determinants for the behavioral intention to play IL games. However, relevance, confidence, cognitive enjoyment, and behavioral enjoyment were not found to predict their behavioral intention.

Research limitations/implications

The authors did not consider other factors in the hypotheses, such as the mediating effects of enjoyment on behavioral intention, and the influence of students’ individual characters such as learning styles or personalities on their behavioral intention of using DGBL. Further, the IL game used in the study, Library Escape, may reduce generalizability of the results. The study used self-reported attitudinal data from survey questionnaires, while behavioral data were not considered.

Practical implications

The results showed that pedagogical features, enjoyment factors, and perceived usefulness remain critical in the uptake of IL games by students. Further, the study demonstrated that instead of behavioral or cognitive dimensions of enjoyment, players are more concerned with affective enjoyment. Hence, developing DGBL with affective features should be pursued.

Originality/value

By taking into consideration both pedagogical and gameplay characteristics of DGBL to explain students’ acceptance of IL games, this study integrates and extends previous studies in the context of IL games. Additionally, instead of using perceived enjoyment as a single dimensional construct, this study adopted a multifaceted, more nuanced perspective on the perceived enjoyment of DGBL.
Information need as trigger and driver of information seeking: a conceptual analysis
Authors: Savolainen Reijo
Published: January 2017

Purpose

The purpose of this paper is to elaborate the picture of the motivators for information behaviour by examining the nature of information need as a trigger and driver of information seeking.

Design/methodology/approach

A conceptual analysis was made by focussing on the ways in which researchers have conceptualised information need in models for human information behaviour (HIB). The study draws on conceptual analysis of 26 key studies focussing on the above topic.

Findings

Researchers have employed two main approaches to conceptualise information needs in the HIB models. First, information need is approached as a root factor which motivates people to identify and access information sources. Second, information need is approached as a secondary trigger or driver determined by more fundamental factors, for example, the information requirements of task performance. The former approach conceptualises information need as a trigger providing an initial impetus to information seeking, while the latter approach also depicts information need as a driver that keeps the information-seeking process in motion. The latter approach is particularly characteristic of models depicting information seeking as a cyclic process.

Research limitations/implications

As the study focusses on information need, no attention is devoted to related constructs such as anomalous state of knowledge and uncertainty.

Originality/value

The study pioneers by providing an in-depth analysis of the nature of information need as a trigger and driver of information seeking. The findings refine the picture of motivators for information behaviour.
Modelling of a VSC-based multi-terminal HVDC network for dynamic stability analysis
Authors: Shinoda Kosei , Guillaud Xavier , Bacha Seddik , Benchaib Abdelkrim , Francois Bruno
Published: January 2017

Purpose

Self-commuted voltage source converter (VSC) can significantly extend the flexibility and operability of an HVDC system and be used to implement the concept of multi-terminal HVDC (MTDC) grid. To take full advantage of MTDC systems, its overall behaviour must be characterized in quasi static and dynamic states. Based on the numerous literatures, a dedicated two-level VSC model and its local controllers and DC grid voltage regulators are developed for this purpose. Furthermore, the requirement of the system to guarantee all the physical constrains must be well assessed and concrete demonstrations must be provided by numerical simulations.

Design/methodology/approach

First, a two-level VSC model and its local controllers and DC grid voltage regulators are developed. Then, DC cable models are investigated and their characteristics are assessed in the frequency domain. Those developed models are combined to form a three-terminal HVDC grid system on Matlab/Simulink platform. To analyze the stability of this electrical system, the dynamics of the system against variations of power dispatch are observed.

Findings

To analyze the stability of this electrical system, the dynamics of the system against variations of power dispatch are observed. The differences in the DC grid voltage dynamics and the power flow of the converter stations coming from the embedded primary controls are analysed, and the technical requirements for both cases are assessed.

Originality/value

In this paper, the dynamic stability of an MTDC system has been analysed and assessed through an adequate simulation model, including its control scheme and the cable models. The interest of the improved PI model for cables is highlighted.
Design of an energy storage system based on vanadium redox flow battery considering a simplified model of VRB
Authors: Lei Jiazhi , Gong Qingwu , Ye Jun
Published: January 2017

Purpose

This paper aims to propose a simplified model of vanadium redox flow batteries (VRBs) for VRB energy storage system (ESS) design considering the operational characteristics of VRB, and a VRB ESS, considering the low terminal voltage of VRB, was presented.

Design/methodology/approach

According to the designed topology of VRB ESS and the simplified model of VRB, a small perturbation analysis method was used to establish the transfer function of VRB ESS, and the controller parameters of VRB ESS under constant charging and discharging current were designed.

Findings

Test results have demonstrated that this designed VRB ESS has fast response, small overshoot, strong adaptation and high steady precision, which strongly verified the reasonable design.

Practical implications

This simplified model of VRB can be suitably used for VRB ESS design. This designed VRB ESS realized the bidirectional power flow of VRB and AC grid. In this designed VRB ESS, phase-shifted full-bridge converter and a single-phase inverter were used and VRB was charged and discharged under constant current.

Originality/value

The paper presents a topology of VRB ESS which can realize the bidirectional power flow of VRB and AC grid. Considering the complexity of VRB model, a simplified model of VRB was proposed for the controller parameters design of VRB ESS, and this method can be used in application.
Detection of time-varying inter-turn short-circuit in a squirrel cage induction machine by means of generalized regression neural network
Authors: Pietrowski Wojciech
Published: January 2017

Purpose

Diagnostics of electrical machines is a very important task. The purpose of this paper is the presentation of coupling three numerical techniques, a finite element analysis, a signal analysis and an artificial neural network, in diagnostics of electrical machines. The study focused on detection of a time-varying inter-turn short-circuit in a stator winding of induction motor.

Design/methodology/approach

A finite element method is widely used for the calculation of phase current waveforms of induction machines. In the presented results, a time-varying inter-turn short-circuit of stator winding has been taken into account in the elaborated field-circuit model of machine. One of the time-varying short-circuit symptoms is a time-varying resistance of shorted circuit and consequently the waveform of phase current. A general regression neural network (GRNN) has been elaborated to find a number of shorted turns on the basis of fast Fourier transform (FFT) of phase current. The input vector of GRNN has been built on the basis of the FFT of phase current waveform. The output vector has been built upon the values of resistance of shorted circuit for respective values of shorted turns. The performance of the GRNN was compared with that of the multilayer perceptron neural network.

Findings

The GRNN can contribute to better detection of the time-varying inter-turn short-circuit in stator winding than the multilayer perceptron neural network.

Originality/value

It is argued that the proposed method based on FFT of phase current and GRNN is capable to detect a time-varying inter-turn short-circuit. The GRNN can be used in a health monitoring system as an inference module.
Model refinements of transformers via a subproblem finite element method
Authors: Dular Patrick , Kuo-Peng Patrick , Ferreira da Luz Mauricio Valencia , Krahenbuhl Laurent
Published: January 2017

Purpose

This paper aims to develop a methodology for progressive finite element (FE) modeling of transformers, from simple to complex models of both magnetic cores and windings.

Design/methodology/approach

The progressive modeling of transformers is performed via a subproblem (SP) FE method. A complete problem is split into SPs with different adapted overlapping meshes. Model refinements are performed from ideal to real flux tubes, one-dimensional to two-dimensional to three-dimensional models, linear to nonlinear materials, perfect to real materials, single wire to volume conductor windings and homogenized to fine models of cores and coils, with any coupling of these changes.

Findings

The proposed unified procedure efficiently feeds each SP via interface conditions (ICs), which lightens mesh-to-mesh sources transfers and quantifies the gain given by each refinement on both local fields and global quantities, with a clear view on its significance to justify its usefulness, if any. It can also help in education with a progressive understanding of the various aspects of transformer designs.

Originality/value

Models of different accuracy levels are sequenced with successive additive corrections supported by different adapted meshes. The way the sources act at each correction step, up to the full models with their actual geometries, is given a particular care and generalized, allowing the proposed unified procedure. For all the considered corrections, the sources are always of IC type, thus only needed in layers of FE along boundaries, which lightens the required mesh-to-mesh projections between subproblems.
Design optimization of ferrite assisted synchronous reluctance motor using multi-objective differential evolution algorithm
Authors: V.S. Nagarajan , Mahadevan Balaji , V. Kamaraj , R. Arumugam , Nagarajan Ganesh , S. Srivignesh , M. Suudharshana
Published: January 2017

Purpose

The purpose of this paper is performance enhancement of ferrite-assisted synchronous reluctance (FASR) motor using multi-objective differential evolution (MODE) algorithm, considering the significant geometric design parameters.

Design/methodology/approach

This work illustrates the optimization of FASR motor using MODE algorithm to enhance the performance of the motor considering barrier angular positions, magnet height, magnet axial length, flux barrier angles of the rotor and air gap length. In the optimization routine to determine the performance parameters, generalized regression neural network-based interpolation is used. The results of MODE are validated with multi-objective particle swarm optimization algorithm and multi-objective genetic algorithm.

Findings

The design optimization procedure developed in this work for FASR motor aims at achieving multiple objectives, namely, average torque, torque ripple and efficiency. With multiple objectives, it is essential to give the designer the tradeoff between different objectives so as to arrive at the best design suitable for the application. The results obtained in this work justify the application of the MODE approach for FASR motor to determine the various feasible solutions within the bounds of the design.

Research limitations/implications

Analysis, design and optimization of synchronous reluctance motor has been explored in detail to establish its potential for variable speed applications. In recent years, the focus is toward the electromagnetic design of hybrid configurations such as FASR motor. It is in this preview this work aims to achieve optimal design of FASR motor using multi-objective optimization approach.

Practical/implications

The results of this work will supplement and encourage the application of FASR motor as a viable alternate for variable speed drive applications. In addition, the application of MODE to arrive at better design solutions is demonstrated.

Originality/value

The approach presented in this work focuses on obtaining enhanced design of FASR motor considering average torque, torque ripple and efficiency as performance measures. Theposteriorianalysis of optimization provides an insight into the choice of parameters involved and their effects on the design of FASR motor. The efficacy of the optimization routine is justified in comparison with other multi-objective algorithms.
Novel cat swarm optimization algorithm to enhance channel equalization
Authors: D.C. Diana , S.P. Joy Vasantha Rani
Published: January 2017

Purpose

Adaptive equalization plays an important role in digital communication to reduce the distortions due to inter-symbol interference. An adaptive filter is used as an equalizer model in channel equalization. An adaptive algorithm is the heart of the adaptive filter which finds the optimum coefficients of the filter. The choice of the adaptive algorithm improves the convergence rate and minimizes the mean square error (MSE). This paper aims to propose a cat swarm optimization (CSO)-based adaptive algorithm and its modification to improve the performance of a channel equalizer.

Design/methodology/approach

The input digital training data are transmitted through different channel conditions. A linear transversal filter is used as a channel and equalizer model. The equalizer coefficients are trained by the proposed simplified cat swarm optimization (SCSO) algorithm to find the estimated digital training data.

Findings

The performance of the proposed SCSO algorithm is compared with particle swarm optimization (PSO)-based channel equalization. The improvement in convergence rate and MSE is verified under linear and nonlinear channel conditions with different delay spreads. The optimum parameters of the SCSO are found using simulation-based sensitivity analysis.

Originality/value

This paper analyzes a CSO algorithm for adaptive channel equalization and proposes a SCSO algorithm to identify the optimum coefficients of a transversal equalizer. The seeking mode process is simplified in the proposed SCSO to achieve better performance in channel equalization. The proposed SCSO algorithm guarantees minimum MSE in all independent runs, whereas in PSO, few misses are possible.
A species effect on storm erosion: Invasive sedge stabilized dunes more than native grass during Hurricane Sandy
Authors: Charbonneau Bianca R. , Wootton Louise S. , Wnek John P. , Langley J. Adam , Posner Michael A.
Published: January 2017

Vegetation and biogeomorphology are highly coupled in beach dune systems, but plant species effects on abating storm erosion are largely unexplored.

We quantified coastal dune erosion from Hurricane Sandy (October 2012) as a function of pre‐storm system characteristics – dune height, beach width and dominant vegetation stabilizing dunes (native Ammophila breviligulata or invasive Carex kobomugi) at Island Beach State Park, New Jersey, USA. We assessed dune erosion using a combination of pre‐ and post‐Sandy aerial image spatial analyses in ArcGIS and GPS field mapping. Our two erosion metrics are novel, macroscale 2D surface area changes and Dune Crest Transgression, the later of which is measured at the microscale (1 m−1) and analysed using a mixed model incorporating spatial autocorrelation.

We document a species‐specific effect on collision erosion. Although C. kobomugi reduces native diversity and abundance, it may be beneficial for coastal protection, as dunes fronted and stabilized by C. kobomugi suffered less erosion than those dominated by A. breviligulata under the same abiotic conditions.

Dune height and beach width were equal for species prior to the storm and therefore do not account for or confound differences in erosion. Similarly, traditional calculations of erosion with volumetric loss confer these results.

Synthesis and applications. This is the first study to show a species effect on coastal dune erosion. Native Ammophila breviligulata stabilized dune stretches suffered more erosion from Hurricane Sandy than complimentary invasive Carex kobomugi stretches, contradicting anecdotal reports that foredunes stabilized by a shorter statured species are more prone to erosion. This study highlights the importance of vegetation for dune stability and management using two novel metrics for erosion. Our erosion metrics are related to volumetric loss, can be monitored and calculated by managers with or without remote sensing, and can be applied to other systems. Discussions on coastal management of dunes as habitats and protective buffers must include vegetation and the results of this study suggest that not all species are equal with regard to their ability to combat storm erosion. Multidisciplinary studies with applied implications will grow increasingly important as storms continue to grow more frequent, severe and unpredictable with climate change.
Generalization and maintenance of treatment gains in primary progressive aphasia (PPA): a systematic review
Authors: Cadório Inês , Lousada Marisa , Martins Paula , Figueiredo Daniela
Published: January 2017

Background

Cognitive–linguistic treatments and interventions targeting communication have been developed within the context of primary progressive aphasia (PPA), however knowledge about the scope of generalization and maintenance of therapy gains considering PPA subtypes remains scarce and awaits systematic investigation.

Aims

To analyse the effects of semantic therapy on generalization and maintenance of treatment outcomes in individuals with PPA, considering its different subtypes.

Methods & Procedures

Central, PubMed, Medline, Web of Knowledge and Scopus were used to retrieve articles of interest. A total of 25 non‐randomized studies published between 2000 and 2016 met the eligibility criteria and therefore were included in this study.

Main Contribution

This systematic review provides evidence‐based information for clinical practice in PPA. Generalization and maintenance effects post‐treatment for each PPA variant are analysed and discussed. Several factors are described as important to maximize the scope for generalization and maintenance of treatment gains.

Conclusions & Implications

Generalization is particularly hard to achieve in the semantic variant, as in the face of degraded semantic knowledge learning is rigid and context dependent. In contrast, non‐fluent and logopenic variants offer better scope for generalization. Maintenance patterns do not seem to be influenced by PPA subtype, but rather by other factors such as continued practice, treatment length and frequency of sessions. In the future, clinicians should consider the PPA subtype when planning the treatment protocol.
Evaluation of Acute Alcohol Intoxication as the Primary Cause of Death: A Diagnostic Challenge for Forensic Pathologists
Authors: Li Rong , Hu Li , Hu Lingli , Zhang Xiang , Phipps Rebecca , Fowler David R. , Chen Feng , Li Ling
Published: January 2017

Deaths caused by acute alcohol intoxication (AAI) remain a major public health issue. This study is retrospective and descriptive: an 8‐year case analysis of deaths due to AAI in Maryland. Study showed that of 150 AAI deaths, the death rate among Hispanics (10.41/100,000 population) was significantly higher than all the non‐Hispanics combined (1.88/100,000 population). The majority of individuals were young adults, overweight, and binge drinkers. The obese group showed significantly lower mean heart and peripheral blood alcohol concentration (BAC) (0.36%, 0.37%) than the normal weight group (0.45%, 0.42%). Based on the PBAC and urine AC ratio, 49.6% deaths likely occurred close to peak phase, followed by postabsorptive phase (31.6%) and absorptive phase (18.8%). Our results indicate that forensic pathologists should evaluate postmortem BAC in the light of individual's age, drinking history, body weight, possible phase of alcohol intoxication, and other autopsy findings when certifying AAI as primary cause of death.
Vitamin D serum levels are cross‐sectionally but not prospectively associated with late‐life depression
Authors: Jovanova O. , Aarts N. , Noordam R. , Carola‐Zillikens M. , Hofman A. , Tiemeier H.
Published: January 2017

Objective

The evidence for a prospective association of vitamin D deficiency with the occurrence of late‐life depression is limited. We aimed to study the long‐term association between vitamin D serum levels and depression in a large population‐based study of older adults.

Method

We included 3251 participants from the Rotterdam Study, aged 55 and older with 32 400 person‐years follow‐up for depression. Baseline 25‐hydroxyvitamin D (25(OH)D) serum levels were analyzed continuously and categorically. Repeated depressive symptoms' questionnaire assessments were used to assess the change of depressive symptoms. Semistructured psychiatric interviews, and GP records were used to assess incident major depressive disorder according to DSM‐IV criteria.

Results

Low serum vitamin D levels were cross‐sectionally associated with more depressive symptoms. However, low 25(OH)D serum levels were not prospectively associated with change of depressive symptoms (unstandardized beta = 0.02, 95% CI = −0.23; 0.26) or incident MDD (hazard ratio = 0.95, 95% CI = 0.86; 1.05).

Conclusion

We observed a cross‐sectional but no prospective association between serum vitamin D levels and depression. A cross‐sectional association in the absence of the longitudinal association can mostly be attributed to reverse causality or residual confounding. Probably, vitamin D deficiency is not an independent risk factor for depression but co‐occurs with late‐life depression.