bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation in Pediatric Care Between Academic and Nonacademic US Emergency Departments, 1995–2010
Authors: Li Joyce , Monuteaux Michael C. , Bachur Richard G.
Published: January 2017

Objectives

The aim of this study was to describe the resource utilization for children with common pediatric conditions treated in academic and nonacademic emergency departments (EDs).

Methods

We performed a retrospective, cross-sectional descriptive study using the National Hospital Ambulatory Medical Care Survey Data from 1995 to 2010 including children less than 18 years old with a diagnosis of asthma, bronchiolitis, croup, gastroenteritis, fever, febrile seizure, or afebrile seizure. Academic EDs (A-ED) were those with greater than 25% of patients seen by a trainee. For each condition, we reported the proportion of testing, medications, and disposition between A-ED and nonacademic EDs (NA-ED).

Results

From 1995 to 2010, approximately 450,000,000 estimated pediatric visits are represented by the survey based on 122,811 actual visits. For most common conditions, testing and disposition were comparable; however, some variation was noted. Among patients with bronchiolitis, a higher proportion of patients was admitted and had radiographs in NA-EDs (18% vs 10% and 56% vs 45%, respectively). For children with croup, radiographs were performed more often at NA-EDs (27% vs 6%). Among those with febrile seizures, more lumbar punctures were performed in NA-EDs (14% vs 0%). In children with afebrile seizures, more head computed tomography scans were obtained at NA-EDs (34% vs 21%).

Conclusion

Among pediatric patients with croup, bronchiolitis, and febrile and afebrile seizure, higher resource utilization and admissions were observed in NA-EDs. These preliminary findings from a national survey require a more detailed investigation into the variation in care between A-ED and NA-ED settings.
Functional characterization of the TAS2R38 bitter taste receptor for phenylthiocarbamide in colobine monkeys
Authors: Purba Laurentia Henrieta Permita Sari , Widayati Kanthi Arum , Tsutsui Kei , Suzuki-Hashido Nami , Hayakawa Takashi , Nila Sarah , Suryobroto Bambang , Imai Hiroo
Published: January 2017

Bitterness perception in mammals is mostly directed at natural toxins that induce innate avoidance behaviours. Bitter taste is mediated by the G protein-coupled receptor TAS2R, which is located in taste cell membranes. One of the best-studied bitter taste receptors is TAS2R38, which recognizes phenylthiocarbamide (PTC). Here we investigate the sensitivities of TAS2R38 receptors to PTC in four species of leaf-eating monkeys (subfamily Colobinae). Compared with macaque monkeys (subfamily Cercopithecinae), colobines have lower sensitivities to PTC in behavioural and
in vitro
functional analyses. We identified four non-synonymous mutations in colobine
TAS2R38
that are responsible for the decreased sensitivity of the TAS2R38 receptor to PTC observed in colobines compared with macaques. These results suggest that tolerance to bitterness in colobines evolved from an ancestor that was sensitive to bitterness as an adaptation to eating leaves.
A Lévy-flight diffusion model to predict transgenic pollen dispersal
Authors: Vallaeys Valentin , Tyson Rebecca C. , Lane W. David , Deleersnijder Eric , Hanert Emmanuel
Published: January 2017

The containment of genetically modified (GM) pollen is an issue of significant concern for many countries. For crops that are bee-pollinated, model predictions of outcrossing rates depend on the movement hypothesis used for the pollinators. Previous work studying pollen spread by honeybees, the most important pollinator worldwide, was based on the assumption that honeybee movement can be well approximated by Brownian motion. A number of recent studies, however, suggest that pollinating insects such as bees perform Lévy flights in their search for food. Such flight patterns yield much larger rates of spread, and so the Brownian motion assumption might significantly underestimate the risk associated with GM pollen outcrossing in conventional crops. In this work, we propose a mechanistic model for pollen dispersal in which the bees perform truncated Lévy flights. This assumption leads to a fractional-order diffusion model for pollen that can be tuned to model motion ranging from pure Brownian to pure Lévy. We parametrize our new model by taking the same pollen dispersal dataset used in Brownian motion modelling studies. By numerically solving the model equations, we show that the isolation distances required to keep outcrossing levels below a certain threshold are substantially increased by comparison with the original predictions, suggesting that isolation distances may need to be much larger than originally thought.
Robert Le Rossignol, 1884–1976: Engineer of the ‘Haber’ process
Authors: Sheppard Deri
Published: January 2017

In March 1908, the BASF at Ludwigshafen provided financial support to Fritz Haber in his attempt to synthesize ammonia from the elements. The process that now famously bears his name was demonstrated to BASF in July 1909. However, its engineer was Haber's private assistant, Robert Le Rossignol, a young British chemist from the Channel Islands with whom Haber made a generous financial arrangement regarding subsequent royalties. Le Rossignol left Haber in August 1909 as BASF began the industrialization of their process, taking a consultancy at the Osram works in Berlin. He was interned briefly during World War I before being released to resume his occupation. His position eventually led to His Majesty's Government formulating a national policy regarding released British internees in Germany. After the war Le Rossignol spent his professional life at the GEC laboratories in the UK, first making fundamental contributions to the development of high-power radio transmitting valves, then later developing smaller valves used as mobile power sources in the airborne radars of World War II. Through his share of Haber's royalties, Le Rossignol became wealthy. In retirement, he and his wife gave their money away to charitable causes.
Human embryos culturedin vitroto 14 days
Authors: Morris Samantha A.
Published: January 2017

We know a great deal about the development of the mammalian embryo until the time that the blastocyst implants into the uterus. With model organisms such as the mouse, we have also developed a considerable understanding of development immediately around gastrulation as embryos can be recovered at this stage for short-termin vitroculture. However, the intervening period of development remained a ‘black box’ because it takes place as the blastocyst is implanting into the uterus. Over the past 6 years, techniques pioneered and developed in Magdalena Zernicka-Goetz's laboratory for thein vitroculture of embryos through these implantation stages have opened up this box, affording the first glimpse of embryonic development through these previously hidden stages. Remarkably, the techniques developed with mouse embryos are equally applicable to human embryos, ushering the very first opportunities for studying our own development throughout this time. Here, I outline how the culture methods were developed, paving the way to culture of the human embryo to the point of gastrulation, an accomplishment recognized as the People's Choice for theScientific Breakthrough of 2016in Science magazine. I also discuss the new ethical challenges raised by the possibility of extending the time limits for human embryo culture.
The relationship between health and mating success in humans
Authors: Foo Yong Zhi , Simmons Leigh W. , Rhodes Gillian 
Published: January 2017

Health has been claimed to play an important role in human sexual selection, especially in terms of mate choice. Our preferences for attractive individuals are said to represent evolved adaptations for finding high-quality, healthy mates. If this is true, then we expect health to predict mating success in humans. We tested this hypothesis using several important physiological indicators of health, including immune function, oxidative stress and semen quality, and self-reported measures of sexual behaviour that contribute to mating success. In contrast to our hypothesis, we did not find a relationship between the physiological measures of health and sexual behaviour. Our results provide little support for claims that health, at least the health measures we used, increases mating success in relatively healthy humans.
The ‘dance’ of life: visualizing metamorphosis during pupation in the blow fly
Calliphora vicina
by X-ray video imaging and micro-computed tomography
Authors: Hall Martin J. R. , Simonsen Thomas J. , Martín-Vega Daniel
Published: January 2017

The dramatic metamorphosis from larva to adult of insect orders such as Diptera cannot usually be witnessed because it occurs within an opaque structure. For the cyclorrhaphous dipterans, such as blow flies, this structure is the puparium, formed from the larval cuticle. Here, we reveal metamorphosis within the puparium of a blow fly at higher temporal resolution than previously possible with two-dimensional time-lapse videos created using the X-ray within a micro-computed tomography scanner, imaging development at 1 min and 2 min intervals. Our studies confirm that the most profound morphological changes occur during just 0.5% of the intrapuparial period (approx. equivalent to 1.25 h at 24°C) and demonstrate the significant potential of this technique to complement other methods for the study of developmental changes, such as hormone control and gene expression. We hope this will stimulate a renewed interest among students and researchers in the study of morphology and its astonishing transformation engendered by metamorphosis.
Curvature, metric and parametrization of origami tessellations: theory and application to the eggbox pattern
Authors: Nassar H. , Lebée A. , Monasse L.
Published: January 2017

Origami tessellations are particular textured morphing shell structures. Their unique folding and unfolding mechanisms on a local scale aggregate and bring on large changes in shape, curvature and elongation on a global scale. The existence of these global deformation modes allows for origami tessellations to fit non-trivial surfaces thus inspiring applications across a wide range of domains including structural engineering, architectural design and aerospace engineering. The present paper suggests a homogenization-type two-scale asymptotic method which, combined with standard tools from differential geometry of surfaces, yields a macroscopic continuous characterization of the global deformation modes of origami tessellations and other similar periodic pin-jointed trusses. The outcome of the method is a set of nonlinear differential equations governing the parametrization, metric and curvature of surfaces that the initially discrete structure can fit. The theory is presented through a case study of a fairly generic example: the eggbox pattern. The proposed continuous model predicts correctly the existence of various fittings that are subsequently constructed and illustrated.
Reflections on the value of electron microscopy in the study of heterogeneous catalysts
Authors: Thomas John Meurig
Published: January 2017

Electron microscopy (EM) is arguably the single most powerful method of characterizing heterogeneous catalysts. Irrespective of whether they are bulk and multiphasic, or monophasic and monocrystalline, or nanocluster and even single-atom and on a support, their structures in atomic detail can be visualized in two or three dimensions, thanks to high-resolution instruments, with sub-Ångstrom spatial resolutions. Their topography, tomography, phase-purity, composition, as well as the bonding, and valence-states of their constituent atoms and ions and, in favourable circumstances, the short-range and long-range atomic order and dynamics of the catalytically active sites, can all be retrieved by the panoply of variants of modern EM. The latter embrace electron crystallography, rotation and precession electron diffraction, X-ray emission and high-resolution electron energy-loss spectra (EELS). Aberration-corrected (AC) transmission (TEM) and scanning transmission electron microscopy (STEM) have led to a revolution in structure determination. Environmental EM is already playing an increasing role in catalyst characterization, and new advances, involving special cells for the study of solid catalysts in contact with liquid reactants, have recently been deployed.
Drivers and predictions of coral reef carbonate budget trajectories
Authors: Januchowski-Hartley Fraser A. , Graham Nicholas A. J. , Wilson Shaun K. , Jennings Simon , Perry Chris T.
Published: January 2017

Climate change is one of the greatest threats to the long-term maintenance of coral-dominated tropical ecosystems, and has received considerable attention over the past two decades. Coral bleaching and associated mortality events, which are predicted to become more frequent and intense, can alter the balance of different elements that are responsible for coral reef growth and maintenance. The geomorphic impacts of coral mass mortality have received relatively little attention, particularly questions concerning temporal recovery of reef carbonate production and the factors that promote resilience of reef growth potential. Here, we track the biological carbonate budgets of inner Seychelles reefs from 1994 to 2014, spanning the 1998 global bleaching event when these reefs lost more than 90% of coral cover. All 21 reefs had positive budgets in 1994, but in 2005 budgets were predominantly negative. By 2014, carbonate budgets on seven reefs were comparable with 1994, but on all reefs where an ecological regime shift to macroalgal dominance occurred, budgets remained negative through 2014. Reefs with higher massive coral cover, lower macroalgae cover and lower excavating parrotfish biomass in 1994 were more likely to have positive budgets post-bleaching. If mortality of corals from the 2016 bleaching event is as severe as that of 1998, our predictions based on past trends would suggest that six of eight reefs with positive budgets in 2014 would still have positive budgets by 2030. Our results highlight that reef accretion and framework maintenance cannot be assumed from the ecological state alone, and that managers should focus on conserving aspects of coral reefs that support resilient carbonate budgets.
Sex differences in the epidemiology of tattoo skin disease in captive common bottlenose dolphins (Tursiops truncatus): are males more vulnerable than females?
Authors: Van Bressem Marie-Françoise , Van Waerebeek Koen , Duignan Pádraig J.
Published: January 2017

The clinical and epidemiological features of tattoo skin disease (TSD), caused by cetacean poxviruses, are reported in 257 common bottlenose dolphins (Tursiops truncatus) held in 31 facilities in the USA and Europe. Photographs and biological data of 146 females and 111 males were analyzed. Dolphins were classified into three age classes (0-3; 4-8; over 9 years), approximating the life stages of ‘calves and young juveniles’, ‘juveniles and sub-adults’ and ‘adults’. The youngest dolphins with tattoos were 14 and 15 months old. Minimal TSD persistence varied between 4 and 65 months in 30 dolphins and was over 22 months in those with very large lesions (> 115 mm). In 2012-2014, 20.6% of the 257 dolphins had TSD. Prevalence varied between facilities from 5.6% (n= 18) to 60% (n= 20), possibly reflecting variation in environmental conditions. Prevalence was significantly higher in males (31.5%) than in females (12.3%), a pattern which departs from that observed in free-ranging Delphinidae where there is no gender bias. As with free-ranging Delphinidae, TSD prevalence in captive females varied with age category, being the highest in the 4 to 8 year old. By contrast, prevalence levels in males were high in all age classes. Prevalence of very large tattoos was also higher in males (28.6%, n= 35) than in females (11.1%, n= 18). Combined, these data suggest that captive maleT. truncatusare more vulnerable to TSD than females possibly because of differences in immune response and because males may be more susceptible to captivity-related stress than females.
Machine learning identifies SNPs predictive of advanced coronary artery calcium in ClinSeq® and Framingham Heart Study cohorts
Authors: Oguz Cihan , Sen Shurjo K , Davis Adam R , Fu Yi-Ping , O’Donnell Christopher J , Gibbons Gary H
Published: January 2017

One goal of personalized medicine is leveraging the emerging tools of data science to guide medical decision-making. Achieving this using disparate data sources is most daunting for polygenic traits and requires systems level approaches. To this end, we employed random forests (RF) and neural networks (NN) for predictive modeling of coronary artery calcification (CAC), which is an intermediate end-phenotype of coronary artery disease (CAD). Model inputs were derived from advanced cases in the ClinSeq®discovery cohort (n=16) and the FHS replication cohort (n=36) from 89th−99thCAC score percentile range, and age-matching controls (ClinSeq® n=16, FHS n=36) with no detectable CAC (all subjects were Caucasian males). These inputs included clinical variables (CLIN), genotypes of 57 SNPs associated with CAC in past GWAS (SNP Set-1), and an alternative set of 56 SNPs (SNP Set-2) ranked highest in terms of their nominal correlation with advanced CAC state in the discovery cohort. Predictive performance was assessed by computing the areas under receiver operating characteristics curves (AUC). Within the discovery cohort, RF models generated AUC values of 0.69 with CLIN, 0.72 with SNP Set-1, and 0.77 with their combination. In the replication cohort, SNP Set-1 was again more predictive (AUC=0.78) than CLIN (AUC=0.61), but also more predictive than the combination (AUC=0.75). In contrast, in both cohorts, SNP Set-2 generated enhanced predictive performance with or without CLIN (AUC> 0.8). Using the 21 SNPs of SNP Set-2 that produced optimal predictive performance in both cohorts, we developed NN models trained with ClinSeq® data and tested with FHS data and replicated the high predictive accuracy (AUC>0.8) with several topologies, thereby identifying several potential susceptibility loci for advanced CAD. Several CAD-related biological processes were found to be enriched in the network of genes constructed from these loci. In both cohorts, SNP Set-1 derived from past CAC GWAS yielded lower performance than SNP Set-2 derived from “extreme” CAC cases within the discovery cohort. Machine learning tools hold promise for surpassing the capacity of conventional GWAS-based approaches for creating predictive models utilizing the complex interactions between disease predictors intrinsic to the pathogenesis of polygenic disorders.
Staphylococcus aureusBiofilm Removal by Targeting Biofilm-Associated Extracellular Proteins
Authors: Shukla Sudhir K. , Rao T. Subba
Published: January 2017

Aim

Among cell surface proteins, biofilm-associated protein promotes biofilm development inStaphylococcus aureusstrains. Aim of this study was to investigate proteinase-mediated biofilm dispersion in different isolates ofS. aureus.

Methods and Results

Microtitre plate based biofilm assay showed that 2 μg/mL proteinase K significantly inhibited biofilm development inbap-positiveS. aureusV329 as well as otherS. aureusstrains, i.e. SA7, SA10, SA33, SA352 and but not inbap-mutant M556 and SA392 (a weak biofilm producing strain). However, proteinase K treatment onS. aureusplanktonic cells showed that there was no inhibition of planktonic growth at any concentration of proteinase K when tested up to 32 μg/mL. This observation ruled out the possibility ofS. aureusbiofilm inhibition by altering the cell viability. Proteinase K treatment upon 24 h old preformed biofilms showed an enhanced dispersion ofbap-positive V329 and SA7, SA10, SA33 and SA352 biofilms, however, proteinase K did not affect thebap-mutantS. aureusM556 and SA392 biofilms. Biofilm compositions study before and after proteinase K treatment indicated that Bap might also be involved in eDNA retention in the biofilm matrix that aid in biofilm stability. When proteinase K was used in combination with antibiotics, a synergistic effect in antibiotic efficacy was observed against all biofilm formingS. aureusstrains.

Conclusion

Proteinase K inhibited biofilms growth inS. aureusbovine mastitis isolates but did not affect their planktonic growth. An enhanced dispersion of preformedS. aureusbiofilms was observed upon proteinase K treatment. Proteinase K treatment with antibiotics showed a synergistic effect againstS. aureusbiofilms.

Significance of the study

The study suggests that dispersingS. aureusby protease can be of use while devising strategies againstS. aureusbiofilms. Proteinase K treatment has a wider scope for control ofS. aureusbiofilms.
Production of Multilayer Cell Mass from Olfactory Stem Cell and Its Utilization Potential in Nervous Tissue Regeneration
Authors: Oztel Olga N. , Allahverdiyev Adil , Karaaltin Aysegul Batioglu , Bağırova Melahat , Ovali Ercument
Published: January 2017

Background

Experimental studies performed with human olfactory nerve stem cells haveshown that these cells can ameliorate nerve cell regeneration. Developing a method of repairing nerve damage solely using stem cells without the need of any supporting material is important.

Methods

A multilayer cell mass was obtained from olfactory tissue-derived mesenchymal stem cells with high viability and proliferation capability using a protocol devoid of scaffolds or any other artificial supporting material. First, human olfactory tissue-derived mesenchymal stem cells were isolated, cultured, and characterized. Next, consecutive passages were conducted to obtain multilayer cell growth. The resulting cell mass could be suitable for tissue engineering models as well as nerve cell or tissue regeneration studies in the future.

Results

Viability and adhesive properties of the resulting cell mass were examined and found to be suitable for use in nerve tissue regeneration.

Conclusion

It is suggested that anin vitro-produced olfactory stem cell mass can be applied to a very small damaged region and could have a high potential for microenvironment formation.
Prolonged exposure does not increase soil microbial community response to warming along geothermal gradients
Authors: Radujković Dajana , Verbruggen Erik , Sigurdsson Bjarni D. , Leblans Niki I. W. , Vicca Sara , Weedon James T.
Published: January 2017

Predicting effects of climate change on ecosystem functioning requires knowledge of soil microbial community responses to warming. We used natural geothermal gradients (from +1°C to +19°C above ambient) in two subarctic grasslands to test the hypothesis that long-term exposure (>50 years) intensifies microbial community responses to warming compared to short-term exposure (5-7 years). Community profiles from amplicon sequencing of bacterial and fungal rRNA genes did not support this hypothesis: significant changes relative to ambient were observed from +9°C and upwards in the long-term and from 7°C to 11°C / +3°C to +5°C and upwards in the short-term, for bacteria and fungi, respectively. Our results suggest that bacterial communities in high-latitude grasslands will not undergo lasting shifts in community composition under the warming predicted for the coming 100 years. Fungal communities do appear to be temperature sensitive to the warming within this range, but only for short-term exposures.
Invasion fitness for gene-culture co-evolution in family-structured populations and an application to cumulative culture under vertical transmission
Authors: Mullon Charles , Lehmann Laurent
Published: January 2017

Human evolution depends on the co-evolution between genetically determined behaviors and socially transmitted information. Although vertical transmission of cultural information from parent to off-spring is common in hominins, its effects on cumulative cultural evolution are not fully understood. Here, we investigate gene-culture co-evolution in a family-structured population by studying the invasion fitness of a mutant allele that influences a deterministic level of cultural information (e.g., amount of knowledge or skill) to which diploid carriers of the mutant are exposed in subsequent generations. We show that the selection gradient on such a mutant, and the concomitant level of cultural information it generates, can be evaluated analytically under the assumption that the cultural dynamic has a single attractor point, thereby making gene-culture co-evolution in family-structured populations with multigenerational effects mathematically tractable. We apply our result to study how genetically determined phenotypes of individual and social learning co-evolve with the level of adaptive information they generate under vertical transmission. We find that vertical transmission increases adaptive information due to kin selection effects, but when information is transmitted as efficiently between family members as between unrelated individuals, this increase is moderate in diploids. By contrast, we show that the way resource allocation into learning trades off with allocation into reproduction (the “learning-reproduction trade-off”) significantly influences levels of adaptive information. We also show that vertical transmission prevents evolutionary branching and may therefore play a qualitative role in gene-culture co-evolutionary dynamics. More generally, our analysis of selection suggests that vertical transmission can significantly increase levels of adaptive information under the biologically plausible condition that information transmission between relatives is more efficient than between unrelated individuals.
A Molecular Signature for Anastasis, Recovery from the Brink of Apoptotic Cell Death
Authors: Sun Gongping , Guzman Elmer , Zhou Hongjun Robin , Kosik Kenneth S. , Montell Denise J.
Published: January 2017

During apoptosis, executioner caspase activity has been considered a point of no return. However, recent studies show that cells can survive caspase activation following transient apoptotic stimuli, a process named anastasis. To identify a molecular signature, we performed whole transcriptome RNA sequencing of untreated, apoptotic, and recovering HeLa cells. We found that anastasis is an active, two-stage program. During the early stage, cells transition from growth-arrested to growing. In the late stage, cells change from proliferating to migratory. Strikingly, some early recovery mRNAs were elevated first during apoptosis, implying that dying cells poise to recover, even while still under apoptotic stress. Furthermore, TGFβ-induced Snail expression is required for anastasis, and recovering cells exhibit prolonged elevation of pro-angiogenic factors. This study demonstrates similarities in the anastasis genes, pathways, and cell behaviors to those activated in wound healing. This study identifies a repertoire of potential targets for therapeutic manipulation of this process.
Family history and APOE4 risk for Alzheimer’s Disease impact the neural correlates of episodic memory by early midlife
Authors: Rajah M. N. , Wallace L. M. K. , Ankudowich E. , Yu E. H. , Swierkot A. , Patel R. , Chakravarty M. M. , Naumova D. , Pruessner J. , Joober R. , Gauthier S. , Pasvanis S.
Published: January 2017

Episodic memory impairment is a consistent, pronounced deficit in pre-clinical stages of late-onset Alzheimer’s disease (AD). Individuals with risk factors for AD exhibit altered brain function several decades prior to the onset of AD-related symptoms. In the current event-related fMRI study of spatial context memory we tested the hypothesis that middle-aged adults (MA; 40-58yrs) with a family history of late onset AD (MA+FH), or a combined +FH and apolipoprotein E ε4 allele risk factors for AD (MA+FH+APOE4), will exhibit differences in encoding and retrieval-related brain activity, compared to – FH –APOE4 MA controls. We also hypothesized that the two at-risk MA groups will exhibit distinct patterns of correlation between brain activity and memory performance, compared to controls. To test these hypotheses we conducted multivariate task, and behavior, partial least squares analysis of fMRI data obtained during successful context encoding and retrieval. Our results indicate that even though there were no significant group differences in context memory performance, there were significant differences in brain activity and brain-behavior correlations involving hippocampus, inferior parietal cortex, cingulate, and precuneus in MA with AD risk factors, compared to controls. In addition, we observed that brain activity and brain-behavior correlations in anterior-medial PFC and in ventral visual cortex differentiated the two MA risk groups from each other, and from MAcontrols. Our results indicate that functional differences in episodic memory-related regions are present by early midlife in adults with +FH and +APOE-4 risk factors for late onset AD, compared to middle-aged controls.
The complex origins of strigolactone signalling in land plants
Authors: Bythell-Douglas Rohan , Rothfels Carl J. , Stevenson Dennis W.D. , Graham Sean W. , Wong Gane Ka-Shu , Nelson David C. , Bennett Tom
Published: January 2017

Strigolactones (SLs) are a class of plant hormones that control many aspects of plant growth. The SL signalling mechanism is homologous to that of karrikins (KARs), smoke-derived compounds that stimulate seed germination. In angiosperms, the SL receptor is an α/β hydrolase known as DWARF14 (D14); its close homologue, KARRIKIN INSENSITIVE2 (KAI2), functions as a KAR receptor, and likely recognizes an uncharacterized, endogenous signal. Previous phylogenetic analyses have suggested that the KAI2 lineage is ancestral in land plants, and that canonical D14-type SL receptors only arose in seed plants; this is paradoxical, however, as non-vascular plants synthesize and respond to SLs. Here, we have used a combination of phylogenetic and structural approaches to re-assess the evolution of the D14/KAI2 family in land plants. We analyzed 339 members of the D14/KAI2 family from land plants and charophyte algae. Our phylogenetic analyses show that the divergence between the eu-KAI2 lineage and the DDK (D14/DLK2/KAI2) lineage that includes D14 occurred very early in land plant evolution. We identify characteristic structural features of D14 and KAI2 proteins, and use homology modelling to show that the earliest members of the DDK lineage structurally resemble KAI2, and not D14 proteins. Furthermore, we show that probable SL receptors in non-seed plants do not have D14-like structure. Our results suggest that SL perception has relatively relaxed structural requirements, and that the evolution from KAI2-like to D14-like protein structure in the DDK lineage may have been driven by interactions with protein partners, rather than being required for SL perception itself.
Do journal data sharing mandates work? Life sciences evidence from Dryad
Authors: Thelwall Mike , Kousha Kayvan
Published: January 2017

Purpose

Data sharing is widely thought to help research quality and efficiency. Data sharing mandates are increasingly being adopted by journals and the purpose of this paper is to assess whether they work.

Design/methodology/approach

This study examines two evolutionary biology journals, Evolution and Heredity, that have data sharing mandates and make extensive use of Dryad. It uses a quantitative analysis of presence in Dryad, downloads and citations.

Findings

Within both journals, data sharing seems to be complete, showing that the mandates work on a technical level. Low correlations (0.15-0.18) between data downloads and article citation counts for articles published in 2012 within these journals indicate a weak relationship between data sharing and research impact. An average of 40-55 data downloads per article after a few years suggests that some use is found for shared life sciences data.

Research limitations/implications

The value of shared data uses is unclear.

Practical implications

Data sharing mandates should be encouraged as an effective strategy.

Originality/value

This is the first analysis of the effectiveness of data sharing mandates.
Numerical analysis of skewed squirrel-cage induction motor taking into account interbar current using 3-D finite element method
Authors: Kawase Yoshihiro , Yamaguchi Tadashi , Iwai Yoshiki , Akiyama Koki , Toida Naotaka , Furukawa Tomoyasu , Kawano Hiroshi
Published: January 2017

Purpose

The interbar current of a squirrel-cage induction motor (IM) flows in the steel sheets when the secondary conductor is not insulated from the laminated steel sheets. It was reported that the interbar current loss was increased when skewing the rotor core. This paper aims to analyze a skewed IM using the three-dimensional (3D) finite element method. The effects of rotor skew on the interbar current are clarified.

Design/methodology/approach

In this paper, a skewed squirrel-cage IM is analyzed in three patterns of skewed angle. The calculated results were compared with each other. If all laminated steel sheets are divided by the mesh with actual thickness, the huge calculation time is required. In the method applied in the study, several steel sheets are divided by the mesh with the actual thickness and some steel sheets are assumed to be the steel lump between them to shorten the calculation time.

Findings

The paper describes that the distribution of interbar current loss when rotor is skewed is different from that when rotor is not skewed. In addition, the paper suggests that the larger the skew angle becomes, the larger the interbar current loss becomes.

Originality/value

In this paper, a skewed IM with the consideration of the interbar current in the laminated steel sheets was analyzed using the 3D finite element method. The influences of the rotor skew on the interbar current are clarified.
Mathematical modeling and harmonic analysis of SISFCL
Authors: Sarkar Debraj , Roy Debabrata , Choudhury Amalendu Bikash , Yamada Sotoshi
Published: January 2017

Purpose

A saturated iron core superconducting fault current limiter (SISFCL) has an important role to play in the present-day power system, providing effective protection against electrical faults and thus ensuring an uninterrupted supply of electricity to the consumers. Previous mathematical models developed to describe the SISFCL use a simple flux density-magnetic field intensity curve representing the ferromagnetic core. As the magnetic state of the core affects the efficient working of the device, this paper aims to present a novel approach in the mathematical modeling of the device with the inclusion of hysteresis.

Design/methodology/approach

The Jiles–Atherton’s hysteresis model is utilized to develop the mathematical model of the limiter. The model is numerically solved using MATLAB. To support the validity of model, finite element model (FEM) with similar specifications was simulated.

Findings

Response of the limiter based on the developed mathematical model is in close agreement with the FEM simulations. To illustrate the effect of the hysteresis, the responses are compared by using three different hysteresis characteristics. Harmonic analysis is performed and comparison is carried out utilizing fast Fourier transform and continuous wavelet transform. It is observed that the core with narrower hysteresis characteristic not only produces a better current suppression but also creates a higher voltage drop across the DC source. It also injects more harmonics in the system under fault condition.

Originality/value

Inclusion of hysteresis in the mathematical model presents a more realistic approach in the transient analysis of the device. The paper provides an essential insight into the effect of the core hysteresis characteristic on the device performance.
Small-signal discrete-time modeling of digitally controlled three-phase PWM boost rectifier under balanced voltage
Authors: Zeng Zhiyong , Jin Xiaoliang , Zhao Rongxiang
Published: January 2017

Purpose

The model for digitally controlled three-phase pulse width modulation (PWM) boost rectifiers is a sampled data model, which is different from the continuous time domain models presented in previous studies. The controller, which is tuned according to the model in continuous time domain and discretized by approximation methods, may exhibit some unpredictable performances and even result in unstable systems under some extreme situations. Consequently, a small-signal discrete-time model of digitally controlled three-phase PWM boost rectifier is required. The purpose of this paper is to provide a simple but accurate small-signal discrete-time model of digital controlled three-phase PWM boost rectifier, which explains the effect of the sampling period, modulator and time delays on system dynamic and improves the control performance.

Design/methodology/approach

Based on the Laplace domain analysis and the waveforms of up-down-count modulator, the small signal model of digital pulse width modulation (DPWM) in the Laplace domain is presented. With a combination of state-space average and a discrete-time modeling technique, a simplified large signal discrete time model is developed. With rotation transformation and feed-forward decoupling, the large-signal model is decoupled into a single input single output system with rotation transformation. Then, an integrated small signal model in the Laplace domain is constructed that included the time delay and modulation effect. Implementing the modified z-transform, a small-signal discrete-time model is derived from the integrated small signal model.

Findings

In a digital control system, besides the circuit parameters, the location of pole of open-loop transfer function is also related to system sampling time, affecting the system stability, and the time delay determines the location of the zero of open-loop transfer function, affecting the system dynamic. In addition to the circuit parameters discussed in previous literature, the right half plane (RHP) zero is also determined by the sampling period and the time delay. Furthermore, the corner frequency of the RHP zero is mainly determined by the sampling period.

Originality/value

The model developed in this paper, accounting for the effect of the sampling period, modulator and time delays on the system dynamic, give a sufficient insight into the behavior of the digitally controlled three-phase PWM rectifier. It can also explain the effect of sampling period and control delay time on system dynamic, accurately predict the system stability boundary and determine the oscillation frequency of the current loop in critical stable. The experimental results verify that the model is a simple and accurate control-oriented small-signal discrete-time model for the digitally controlled three-phase PWM boost rectifier.
Analysis of leakage field and current non-uniformity for HTS transformer windings using three dimension coupled field-circuit approach
Authors: Hu Daoyu , Li Zhuyong , Hong Zhiyong , Jin Zhijian
Published: January 2017

Purpose

The purpose of this paper is to analyze the influence of different types of winding configurations on the distribution of leakage field and branch currents for a 330-kVA high-temperature superconducting (HTS) transformer winding.

Design/methodology/approach

A three-dimensional electromagnetic model coupled with a circuit model validated by an experiment is developed to calculate the leakage field and current uniformity under four different types of secondary winding configurations. The four types of gaps between secondary windings are uniform gap, arithmetic progression (AP) gap, six sections with three different gaps and eight sections with four different gaps. A coefficient named as uneven degree is used to define the current nonuniformity.

Findings

The simulation results show that the currents and leakage field of double pancakes (DPs) on both sides are larger than those of the other DPs, and the currents of several middle DPs are smaller than the average rated current with an ISOB gap and larger than the average rated current with an IBOS gap. For any one of the four types of winding configurations, the type with the ISOB gap can prohibit the current nonuniformity more effectively, whereas the IBOS gap can decrease the leakage field more. The AP with the ISOB gap is a wise choice for decreasing the uneven degree and leakage field.

Practical implications

There is an optimal winding configuration for decreasing the leakage field and uneven degree of branch currents. The results and numerical model are very useful for the design of a HTS transformer.

Originality/value

The leakage field distribution and branch currents nonuniformity for 25 parallel DPs are investigated and optimized.
Towards design of electrical machines from given air gap field
Authors: Poutala Arto , Suuriniemi Saku , Tarhasaari Timo , Kettunen Lauri
Published: January 2017

Purpose

The purpose of this paper is to introduce a reverted way to design electrical machines. The authors present a work flow that systematically yields electrical machine geometries from given air gap fields.

Design/methodology/approach

The solution process exploits the inverse Cauchy problem. The desired air gap field is inserted to this as the Cauchy data, and the solution process is stabilized with the aid of linear algebra.

Findings

The results are verified by solving backwards the air gap fields in the standard way. They match well with the air gap fields inserted as an input to the system.

Originality/value

The paper reverts the standard design work flow of electrical motor by solving directly for a geometry that yields the desired air gap field. In addition, a stabilization strategy for the underlying Cauchy problem is introduced.
Modeling and analysis of the effects of the fabrication temperatures on thermal-induced stress and speed performance of nano pMOS transistors
Authors: El Boukili Abderrazzak
Published: January 2017

Purpose

The purpose of this paper is to develop and apply accurate and original models to understand and analyze the effects of the fabrication temperatures on thermal-induced stress and speed performance of nano positively doped metal oxide semiconductor (pMOS) transistors.

Design/methodology/approach

The speed performances of nano pMOS transistors depend strongly on the mobility of holes, which itself depends on the thermal-induced extrinsic stress σ. The author uses a finite volume method to solve the proposed system of partial differential equations needed to calculate the thermal-induced stress σ accurately.

Findings

The thermal extrinsic stress σ depends strongly on the thermal intrinsic stress σ0, thermal intrinsic strain ε0, elastic constants C11 and C12 and the fabrication temperatures. In literature, the effects of fabrication temperatures on C11 and C12 needed to calculate thermal-induced stress σ0have been ignored. The new finding is that if the effects of fabrication temperatures on C11 and C12 are ignored, then, the values of stress σ0and σ will be overestimated and, then, not accurate. Another important finding is that the speed performance of nano pMOS transistors will increase if the fabrication temperature of silicon-germanium films used as stressors is increased.

Practical implications

To predict correctly the thermal-induced stress and speed performance of nano pMOS transistors, the effects of fabrication temperatures on the elastic constants required to calculate the thermal-induced intrinsic stress σ0should be taken into account.

Originality/value

There are three levels of originalities. The author considers the effects of the fabrication temperatures on extrinsic stress σ, intrinsic stress σ0and elastic constants C11 and C12.
A novel diagnostic algorithm for AC series arcing based on correlation analysis of high-frequency component of wavelet
Authors: Wang Yangkun , Zhang Feng , Zhang Shiwen , Yang Guang
Published: January 2017

Purpose

A multi-load available, response reliable and product-friendly method is in urgent need to diagnose the signs of incipient arcing. This paper aims to propose a novel algorithm that originates the application of correlativity analysis of wavelet high-frequency component in state discrimination and further in arcing detection.

Design/methodology/approach

The proposed method calculates the correlation coefficient between the extraction by wavelet transform of arcing series current and that of normal, compares it with a predefined threshold and outputs a trip signal when eight qualified arcing half cycles within a period of 0.5 s are detected.

Findings

Typical appliances are selected in laboratory for arc detection to test the method which carries on independently of impedance type. The algorithm could be optimized to identify arcing for different kinds of loads, including resistive, inductive, capacitive and switching power supply loads, with a same correlation coefficient threshold.

Practical implications

The arithmetic operations of the method are addition and multiplication, which contribute to efficient data computation and transmission for micro-processor to undertake. The reference optimal sampling rate recommended for the algorithm helps to reduce the processed data volume and shows its promising prospect for portable product development.

Originality/value

This proposed correlativity analysis of wavelet transform component algorithm could classify the tested signal into two categories, which benefits the discrimination of normal and fault states in condition monitoring. Laboratory tests prove that it works effectively in arc detection for the commonly used impedance types of loads and needs no offline self-learning or training of samples.
Fast circular shapes detection in cylindrical ECT sensors by design selection and nonlinear black-box modeling
Authors: Oussar Yacine , Margo Cedric , Lucas Jérôme , Holé Stéphane
Published: January 2017

Purpose

Within the framework of image reconstruction in cylindrical electrical capacitance tomography (ECT) sensors, the purpose of this study is to select the structure of a sensor in terms of number and size of the electrodes, to predict the radius and the position of a single circular shape lying in the cross-section defined by the sensor electrodes.

Design/methodology/approach

Nonlinear black-box models using a set of physically independent capacitances and least-square support vector machines models selected with a sophisticated validation method are implemented.

Findings

The coordinates of circular shapes are well estimated in fixed and variable permittivity environments even with noisy data. Various numerical experiments are presented and discussed. Sensors formed by three or four electrodes covering 50 per cent of the sensor perimeter provide the best prediction performances.

Research limitations/implications

The proposed method is limited to the detection of a single circular shape in a cylindrical ECT sensor.

Practical implications

This method can be advantageously implemented in real-time applications, as it is numerically cost-effective and necessitates a small amount of measurements.

Originality/value

The contribution is two-fold: a fast computation of a circular shape position and radius with a satisfactory precision compared to the sensor size, and the determination of a cylindrical ECT sensor architecture that allows the most efficient predictions.