bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anaerobic ammonium oxidation is a major N-sink in aquifer systems around the world
Authors: Wang Shanyun , Zhu Guibing , Zhuang Linjie , Li Yixiao , Liu Lu , Lavik Gaute , Berg Michael , Liu Sitong , Long Xi-En , Guo Jianhua , Jetten Mike S M , Kuypers Marcel M M , Li Fangbai , Schwark Lorenz , Yin Chengqing 
Published: October 2019

Abstract
Global-scale N-oxide contamination of groundwater within aquifers occurs due to the widespread use of N-bearing fertilizers and chemicals, threatening both human and environmental health. However, the conversion of these pollutants in active nitrogen (N) cycling processes in the subsurface biosphere still remains unclear. This study investigates the global occurrence of anaerobic ammonium oxidation (anammox) in aquifers, where anammox was found to be turned on and off between saturated and unsaturated soil horizons, and contributed 36.8–79.5% to N loss in saturated soil horizons, the remainder being due to denitrification which has traditionally been considered the main pathway for removal of N-pollutants from aquifers. Although anammox activity was undetectable in the unsaturated soil horizons, it could potentially be activated by contact with ascending groundwater. High-throughput pyrosequencing analysis identified Candidatus Brocadia anammoxidans as being the most abundant anammox bacterium in the saturated soils investigated. However, the anammox bacterial abundance was determined by the relative richness of Candidatus Jettenia asiatica. Isotopic pairing experiments revealed that coupling anammox with ammonium oxidation and respiratory ammonification enabled the formation of a revised N cycle in aquifer systems, in which respiratory ammonification acted as an important coordinator. Anammox can therefore contribute substantially to aquifer N cycling and its role in remediation of aquifers contaminated with N-oxides may be of global importance.
Genomic, transcriptomic, and proteomic insights into the symbiosis of deep-sea tubeworm holobionts
Authors: Yang Yi , Sun Jin , Sun Yanan , Kwan Yick Hang , Wong Wai Chuen , Zhang Yanjie , Xu Ting , Feng Dong , Zhang Yu , Qiu Jian-Wen , Qian Pei-Yuan 
Published: October 2019

Abstract
Deep-sea hydrothermal vents and methane seeps are often densely populated by animals that host chemosynthetic symbiotic bacteria, but the molecular mechanisms of such host-symbiont relationship remain largely unclear. We characterized the symbiont genome of the seep-living siboglinid Paraescarpia echinospica and compared seven siboglinid-symbiont genomes. Our comparative analyses indicate that seep-living siboglinid endosymbionts have more virulence traits for establishing infections and modulating host-bacterium interaction than the vent-dwelling species, and have a high potential to resist environmental hazards. Metatranscriptome and metaproteome analyses of the Paraescarpia holobiont reveal that the symbiont is highly versatile in its energy use and efficient in carbon fixation. There is close cooperation within the holobiont in production and supply of nutrients, and the symbiont may be able to obtain nutrients from host cells using virulence factors. Moreover, the symbiont is speculated to have evolved strategies to mediate host protective immunity, resulting in weak expression of host innate immunity genes in the trophosome. Overall, our results reveal the interdependence of the tubeworm holobiont through mutual nutrient supply, a pathogen-type regulatory mechanism, and host-symbiont cooperation in energy utilization and nutrient production, which is a key adaptation allowing the tubeworm to thrive in deep-sea chemosynthetic environments.
The Relationship Between Tri-ponderal Mass Index and Metabolic Syndrome and Its Components in Youth Aged 10–20 Years
Authors: Shim Young Suk 
Published: October 2019

AbstractThe current study aimed to evaluate the distribution of the tri-ponderal mass index (TMI) according to sex and age and the relationship of obesity groups according to sex- and age-specific TMI with metabolic syndrome (MetS) and its components. A total of 8,464 subjects aged 10–20 years were classified into 4 groups according to sex- and age-specific TMI: (i) underweight, (ii) normal weight, (iii) overweight, and (iv) obese. The range of the 50th percentiles of TMI was from 13.24 kg/m3 at 10 years to 12.94 kg/m3 at 20 years among males and from 12.19 kg/m3 to 12.84 kg/m3 among females. In the analysis of covariance, obesity groups according to sex- and age-specific TMI were positively correlated with waist circumference (WC) standard deviation score; systolic blood pressure (BP); diastolic BP; and levels of glucose, total cholesterol, triglycerides (TGs), and low-density lipoprotein cholesterol, but for both sexes, the obesity groups were negatively related to high-density lipoprotein cholesterol (HDL-C). In the multiple logistic regression, subjects in the overweight group had higher odds ratios (ORs) for elevated WC (29.18), elevated BP (1.33), elevated TGs (2.55), reduced HDL-C (2.31), and MetS (8.93) than those with normal weight. Participants in the obesity group had increased ORs for elevated WC (154.67), elevated BP (2.22), elevated glucose (3.54), elevated TGs (4.12), reduced HDL-C (3.69), and MetS (25.57) compared to participants with normal weight after adjustment for confounders. Our results suggest that sex- and age-specific TMI may be applicable in the clinical setting as a useful screening tool.
Neural correlates of positive and negative symptoms through the illness course: an fMRI study in early psychosis and chronic schizophrenia
Authors: Vanes Lucy D. , Mouchlianitis Elias , Patel Krisna , Barry Erica , Wong Katie , Thomas Megan , Szentgyorgyi Timea , Joyce Dan , Shergill Sukhwinder 
Published: October 2019

AbstractPsychotic illness is associated with cognitive control deficits and abnormal recruitment of neural circuits subserving cognitive control. It is unclear to what extent this dysfunction underlies the development and/or maintenance of positive and negative symptoms typically observed in schizophrenia. In this study we compared fMRI activation on a standard Stroop task and its relationship with positive and negative symptoms in early psychosis (EP, N = 88) and chronic schizophrenia (CHR-SZ, N = 38) patients. CHR-SZ patients showed reduced frontal, striatal, and parietal activation across incongruent and congruent trials compared to EP patients. Higher positive symptom severity was associated with reduced activation across both trial types in supplementary motor area (SMA), middle temporal gyrus and cerebellum in EP, but not CHR-SZ patients. Higher negative symptom severity was associated with reduced cerebellar activation in EP, but not in CHR-SZ patients. A negative correlation between negative symptoms and activation in SMA and precentral gyrus was observed in EP patients and in CHR-SZ patients. The results suggest that the neural substrate of positive symptoms changes with illness chronicity, and that cognitive control related neural circuits may be most relevant in the initial development phase of positive symptoms. These findings also highlight a changing role for the cerebellum in the development and later maintenance of both positive and negative symptoms.
Analysis of end effect in ironless stator AFPM machine via MEC model
Authors: Gao Huamin , Zhang Zhuoran , Wang Chen , Geng Weiwei , Liu Ye 
Published: October 2019

The Halbach‐array permanent magnet (PM) rotors can achieve higher air‐gap flux density due to magnetic flux gathering effect, which contributes to the higher‐torque density improvement of the ironless stator axial flux PM (AFPM) machine. However, the end leakage fluxes of the ironless stator AFPM machine are serious due to the large magnetic resistance of the main flux loop in ironless stator machines. Circular arc straight line permeance model is adopted to calculate magnet‐to‐magnet and magnet‐to‐rotor end leakage fluxes based on the analysis of the relationship between end leakage fluxes and coils. A magnetic equivalent circuit (MEC) model is established considering end leakage fluxes. The leakage coefficients representing the ratio of end leakage fluxes to main flux and radial coefficients representing effective radial lengths of end leakage fluxes are analysed via the MEC model. The coefficients vary with machine parameters including PM thickness, rotor yoke thickness and air‐gap length. On the basis of the analysis results, the influence factors of end leakage fluxes are summarised and the 50 kW ironless stator AFPM machine is optimised. Finally, a 50 kW ironless stator AFPM machine with Halbach‐array PM rotors is prototyped to verify the results of the finite element analysis and MEC model.
HIF detection in distribution networks based on Kullback–Leibler divergence
Authors: Nezamzadeh‐Ejieh Shiva , Sadeghkhani Iman 
Published: October 2019

A high‐impedance fault (HIF) is mostly associated with the arcing phenomenon, and its main features are low current, randomness, non‐linearity, and asymmetry. The low fault current of an HIF is a major challenge for overcurrent‐based protection system of distribution networks. Power loss, potential fire hazard, and electric shock are consequences of an undetected HIF. This study presents a time‐domain HIF detection algorithm based on monitoring the substation current waveform. Using the Kullback–Leibler divergence similarity measure, the non‐linearity, and asymmetry features of two subsequent half cycles of the current waveform are quantified as the HIF detection criterion. A time duration‐based criterion is also used to distinguish HIFs from the load, capacitor, feeder, and distributed energy resource switchings and the voltage sag and swell events. The proposed scheme satisfactorily works in the presence of non‐linear loads. Also, it does not require the training data set, transformation, and calculation of harmonic/sequence components. Extensive time‐domain simulation case studies using the IEEE 13 and 34 node test feeders demonstrate the merits of the proposed HIF detection algorithm.
Output voltage tracking controller embedding auto‐tuning algorithm for DC/DC boost converters
Authors: Choi Kyunghwan , Kim Yonghun , Kim Kyung‐Soo , Kim Seok‐Kyoon 
Published: October 2019

This study suggests a non‐linear output voltage tracking controller for DC/DC boost converters in the form of a classical cascade control structure. Non‐linearities in the converter dynamics as well as parameter uncertainties and load variations are considered. The first contribution of this study is the design of an auto‐tuner, which automatically adjusts the control gain according to the output voltage error to enhance transient performance. The second contribution involves proving that the closed‐loop system ensures the performance recovery without any steady‐state errors in the presence of parameter and load variations. The effectiveness of the proposed algorithm was verified through experimental investigations using a 5 kW prototype DC/DC boost converter.
Modified single‐switch bridgeless PFC SEPIC structure by eliminating circulating current and power quality improvement
Authors: Romai Noor Mohamad Kamil , Ponniran Asmarashid , Abdul Rashid Munirah Az Zahra , Jumadril J.N. , Yatim Mohd Hafizie , Kasiran Mohd Amirul Naim , Bakar Afarulrazi Abu , Shah Shaharil Mohd , Muhammad Khairul Safuan , Itoh Jun‐ichi 
Published: October 2019

In this study, a modified single‐switch bridgeless power factor correction (PFC) single‐ended primary‐inductor converter (SEPIC) structure is proposed. The major practical drawbacks of the existing structure are the presence of circulating current and high maximum current stress at the input capacitor and line diodes. Therefore, to overcome these problems, the existing structure is restructured by repositioning the line diodes in series with input inductors. Besides, the principle of design parameters optimisation is used based on the balancing energy compensation between input capacitors and output inductor. This structure is designed to operate in discontinuous conduction mode in order to achieve almost a unity power factor. The operation principle and design consideration of the modified structure is introduced in details. The experimental results demonstrate that the total harmonic distortion current is reduced from 56.3 to 4.9% after the optimisation process is performed, and at the same time the dead zones are inherently eliminated. Furthermore, it is shown that the output voltage ripple frequency is always double from the input line frequency of 50 Hz and the output voltage ripple is constantly lower than the maximum input voltage ripple. Thus, the designed parameters of the experimental converter are verified with ∼160 W of the converter output power.
SiC‐based active quasi‐Z‐source inverter with improved PWM control strategy
Authors: Duong Truong‐Duy , Nguyen Minh‐Khai , Lim Young‐Cheol , Choi Joon‐Ho , Vilathgamuwa D. Mahinda 
Published: October 2019

In this study, an improved pulse width modulation (PWM) scheme was proposed for an active quasi‐Z source inverter (AqZSI). Compared to the quasi‐Z‐source inverter (qZSI), the AqZSI with improved PWM strategy can operate in a wide range of input voltage with higher efficiency. Furthermore, the AqZSI can operate with a higher modulation index, a lower inductor current stress, and a reduced shoot‐through current. A procedure flowchart is presented for the optimal selection of the shoot‐through duty cycle, the switching ratio of the additional switch, and the modulation index for AqZSI. Moreover, some comparative results between the AqZSI, qZSI and conventional two‐stage inverter with a boost DC–DC converter are shown in detail. Finally, 1.2 kVA SiC‐based three‐phase inverter prototypes are built to verify the agreement between theory and measurement.
Regenerative switched‐inductor/capacitor type DC–DC converter with large voltage gain for PV applications
Authors: Karthikeyan Venkitusamy , Sundaramoorthy Kumaravel , Guru Kumar Gangavarapu , Babaei Ebrahim 
Published: October 2019

In grid‐connected PV applications, the presence of a transformer not only increases the cost, size and weight, but also decreases the whole system efficiency, especially, under poor irradiation conditions. To eliminate the transformer and to meet DC link voltage, a regenerative switched‐inductor/capacitor type DC–DC converter with large voltage gain is proposed in this study. In traditional boost type and derived converters, the voltage gain ratio is limited due to voltage stress on the semiconductor devices and low efficiency because of more components count and large duty cycle operation. The proposed converter recycles the energy in lossless passive components and increases the step‐up voltage gain, which improves the efficiency. In addition, the converter possesses fewer ripples and smooth continuous current, which reduces the power loss, elongates lifespan of the input source and restricts electromagnetic interference issues. This study presents detailed operating waveforms, modes of operation and performance characteristics of the proposed converter. In order to validate the operation, 500 W experimental prototype is developed and verified with measured results. The proposed converter yields the peak efficiency of 95.20% for the output power of 440 W.
Single‐switch high step‐up boost converter based on a novel voltage multiplier
Authors: Zhu Binxin , Wang Han , Vilathgamuwa Don Mahinda 
Published: October 2019

A single‐switch high step‐up boost converter based on a novel voltage multiplier (VM) has been proposed in this study. Compared to traditional boost converter, not only the voltage conversion ratio has been increased, but also voltage stress across semiconductor devices has been decreased. Moreover, the voltage conversion ratio and voltage stress of switch of the proposed converter can be adjusted by the number of the VM cells. The control and drive circuits for the proposed converter is as simple as boost converter as there are no additional switches. Working principles and performance characteristics of the proposed converter have been analysed in detail. A 200 W experimental prototype with three VMs has been built to validate the theoretical analysis.
Structural and optical properties of Ce doped BiFeO3 nanoparticles via sol–gel method
Authors: Li Jin , Guan Xiao Ying 
Published: October 2019

The effect of Ce doping on the structural and optical properties of BiFeO3 nanoparticles via sol–gel method is reported. All samples were a pure phase with perovskite structure. The EDX results show the doped samples contain Bi, Fe, O and Ce elements. The vibrational properties of samples were studied using Raman spectroscopy. Photoluminescence shows an intense peak at 398 nm, the peak strength enhanced greatly and had redshift with the increase of Ce doping concentration. UV–vis results show the samples have a broad absorption band in the range of 500–600 nm. The bandgaps decrease with the concentration increase of Ce doping. It indicates the as‐prepared BiFeO3 can be used as visible light catalyst.
Measuring relative abundances in the solar corona with optimised linear combinations of spectral lines
Authors: Zambrana Prado Natalia , Buchlin Éric 
Published: October 2019

Context. Elemental abundances in some coronal structures differ significantly from photospheric abundances, with a dependence on the first ionization potential (FIP) of the element. Measuring these FIP-dependent abundance biases is important for coronal and heliospheric physics.
Aims. We aim to build a method for optimal determination of FIP biases in the corona from spectroscopic observations in a way that is in practice independent from differential emission measure (DEM) inversions.
Methods. We optimised linear combinations of spectroscopic lines of low-FIP and high-FIP elements so that the ratio of the corresponding radiances yields the relative FIP bias with good accuracy for any DEM in a small set of typical DEMs.
Results. These optimised linear combinations of lines allow retrieval of a test FIP bias map with good accuracy for all DEMs in the map. The results also compare well with a FIP bias map obtained from observations using a DEM-dependent method.
Conclusions. The method provides a convenient, fast, and accurate way of computing relative FIP bias maps. It can be used to optimise the use of existing observations and the design of new observations and instruments.
The Galactic Faraday depth sky revisited
Authors: Hutschenreuter Sebastian , Enßlin Torsten A. 
Published: October 2019

Context. The Galactic Faraday depth sky is a tracer for both the Galactic magnetic field and the thermal electron distribution. It was previously reconstructed from polarimetric measurements of extra-Galactic point sources.
Aims. Here we improve on these works by using an updated inference algorithm and by taking into account the electron emission measure as traced by free–free emission measured by the Planck survey. In the future the data situation will improve drastically thanks to the next generation Faraday rotation measurements from the SKA and its pathfinders. Anticipating this, a further aim of this paper is to update the map reconstruction method with some of the latest developments in Bayesian imaging.
Methods. To this end we made use of information field theory, an inference scheme that is particularly powerful in cases of noisy and incomplete data.
Results. We demonstrate the validity of the new algorithm by applying it to an existing data compilation. Even though we used exactly the same data set, a number of novel findings are made; for example, a non-parametric reconstruction of an overall amplitude field resembles the free–free emission measure map of the Galaxy. Folding this emission measure map into the analysis provides more detailed predictions. The joint inference enables us to identify regions with deviations from the assumed correlations between the emission measure and Faraday data, thereby pointing us to Galactic structures with distinguishably different physics. We find evidence for an alignment of the magnetic field within the lines of sight along both directions of the Orion arm.
Modeling non-thermal emission from the jet-launching region of M 87 with adaptive mesh refinement
Authors: Davelaar Jordy , Olivares Hector , Porth Oliver , Bronzwaer Thomas , Janssen Michael , Roelofs Freek , Mizuno Yosuke , Fromm Christian M. , Falcke Heino , Rezzolla Luciano 
Published: October 2019

Context. The galaxy M 87 harbors a kiloparsec-scale relativistic jet, whose origin coincides with a compact source thought to be a supermassive black hole. Observational millimeter very long baseline interferometry campaigns are capable of resolving the jet-launching region at the scale of the event horizon. In order to provide a context for interpreting these observations, realistic general-relativistic magnetohydrodynamical (GRMHD) models of the accretion flow are constructed.
Aims. Electrons in the jet are responsible for the observed synchrotron radiation, which is emitted in frequencies ranging from radio to near-infrared (NIR) and optical. The characteristics of the emitted radiation depend on the shape of the electrons’ energy-distribution function (eDF). The dependency on the eDF is omitted in the modeling of the first Event Horizon Telescope results. In this work, we aim to model the M 87 spectral-energy distribution from radio up to optical frequencies using a thermal-relativistic Maxwell–Jüttner distribution, as well as a relativistic κ-distribution function. The power-law index of the eDF is modeled based on sub-grid, particle-in-cell parametrizations for sub-relativistic reconnection.
Methods. A GRMHD simulation in Cartesian–Kerr–Schild coordinates, using eight levels of adaptive mesh refinement (AMR), forms the basis of our model. To obtain spectra and images, the GRMHD data was post-processed with the ray-tracing code RAPTOR, which is capable of ray tracing through GRMHD simulation data that is stored in multi-level AMR grids. The resulting spectra and images maps are compared with observations.
Results. We obtain radio spectra in both the thermal-jet and κ-jet models consistent with radio observations. Additionally, the κ-jet models also recover the NIR and optical emission. The images show a more extended structure at 43 GHz and 86 GHz and more compact emission at 228 GHz. The models recover the observed source sizes and core shifts and obtain a jet power of ≈1043 ergs s−1. In the κ-jet models, both the accretion rates and jet powers are approximately two times lower than the thermal-jet model. The frequency cut-off observed at ν ≈ 1015 Hz is recovered when the accelerator size is 106 − 108 cm, this could potentially point to an upper limit for plasmoid sizes in the jet of M 87.