bluuebunny/crossref_metadata_2025 huggingface dataset:
Complete solutions for the outage probability of maximal ratio combining diversity on Nakagami‐m fading channels with unequal power branches valid for integer m
Authors: Beaulieu Norman C. , Wei Shumei
Published: July 2019

Maximal ratio combining (MRC) diversity is fundamental in wireless communication theory and widely implemented in practice. There are limited results in the theory for the probability density function (PDF) of MRC diversity on Nakagami channels when the branches have unequal powers. In addition to being restricted, the known solutions are complex and in some cases unwieldy. Novel, complete solutions for the PDF of MRC signal‐to‐noise ratio (SNR), valid for integer values of the Nakagami fading parameter m and arbitrary branch powers, are derived. In addition to being solutions for the unsolved cases, the new solutions give different and much simpler expressions for the known restricted cases than previous solutions. The effects of branch channel power imbalances on the PDF of MRC and on the outage probability are investigated quantitatively. The new solutions are used to derive asymptotic large SNR performance measures for MRC diversity with unequal branch powers, insights not obtainable from previous solutions. The new solutions are used to derive intuitive simple approximations for the densities and distributions of MRC output signal power and amplitude, as well as for the outage probability. The approximations are shown to have excellent accuracies for power imbalances 30% and good accuracies for power imbalances 60%.
Security and reliability trade‐off analysis of joint user and jammer selection in the face of co‐channel interference
Authors: Li Bin , Zhou Jianjiang , Zou Yulong , Wang Fei , Cao Weifeng
Published: July 2019

In this study, the authors investigate the security and reliability trade‐off (SRT) performance of a multiuser wireless network, where an eavesdropper attempts to overhear the confidential transmissions between a base station and multiple users under the impact of co‐channel interference. To enhance the SRT performance of the network, the authors propose two joint user and jammer selection schemes, namely the joint optimal user and random jammer selection (JOU‐RJS) scheme and the joint optimal user and optimal jammer selection (JOU‐OJS) scheme. For SRT performance comparison purposes, the traditional multiuser scheduling (TMUS) scheme is also considered. The authors derive closed‐form outage and intercept probability expressions for the JOU‐RJS and JOUOJS schemes. Simulation results show that the SRTs of both JOU‐RJS and JOU‐OJS schemes are better than that of the TMUS scheme, where JOU‐OJS achieves the best SRT performance. Additionally, this study also shows that an expected outage or intercept probability of the TMUS, JOU‐RJS, and JOU‐OJS schemes can be achieved by giving an appropriate overall rate. Finally, the sum of the outage and intercept probability can be minimised through an optimal power allocation between the selected user and friendly jammer for the proposed JOU‐RJS and JOU‐OJS.
Reducing root‐mean‐square current stress on the DC link capacitor of a five‐phase electric drive through multiple carrier pulse‐width modulation technique
Authors: Diana Michela , Maqsood Atif , Corzine Keith , Guglielmi Paolo , Parsa Leila
Published: July 2019

This study investigates the angle of phase shift between interleaved carriers in pulse‐width modulation, as an additional design parameter to reduce the DC link stress of a five‐phase drive. Several phase shift strategies are studied and defined with a focus on the DC link root‐mean‐square current. The effect of adjusting the phase shift between interleaved carriers on the DC link stress is analysed and a general mathematical model is proposed to estimate the effect for any phase shift strategy. The trends predicted by simulations and analytical models have been validated through the application of the control algorithm on a five‐phase motor drive system.
Broken rotor bar fault detection of the grid and inverter‐fed induction motor by effective attenuation of the fundamental component
Authors: Asad Bilal , Vaimann Toomas , Belahcen Anouar , Kallaste Ants , Rassõlkin Anton , Iqbal Muhammad Naveed
Published: July 2019

Since electrical machines are the largest consumer of electricity worldwide, their fault diagnostic at the incipient stage and condition monitoring is essential for better reliability, economy, and safety of operation. Out of several condition monitoring techniques, motor current signature analysis is gaining heightened popularity because of its non‐invasive nature, the least number of sensors required and versatility of compatible algorithms. In this study, the best characteristics of infinite impulse response (IIR) filter are exploited to observe the broken rotor bar (BRB) frequencies with good legibility in current and voltage spectrum of the grid and inverter‐fed motor, respectively. The causes of various harmonics in the stator current spectrum are first investigated for better understanding. The results are taken based on simulation and measurements taken from the laboratory setup. It is observed that a better tuning of IIR filters can make diagnostic algorithms capable of detecting the frequencies of interest by effectively attenuating the fundamental component and reducing its spectral leakage. Moreover, in case of direct torque control‐based industrial inverter‐fed motors, the current cannot be a good candidate for fault diagnostics rather the phase voltage can be effectively used for the detection of BRBs.
Fast and robust map‐matching algorithm based on a global measure and dynamic programming for sparse probe data
Authors: Yokota Takayoshi , Okude Mariko , Sakamoto Toshiyuki , Kitahara Reiji
Published: July 2019

The location data from positioning devices such as those utilising global navigation satellite system (GNSS) provides vital information for the probe‐car systems aiming at solving road‐traffic problems. In the case of the Japanese Electronic Toll Collection System 2.0, a huge amount of probe data can be gathered at intervals of 200 m throughout the country. However, it is not easy for conventional map‐matching algorithms to perform appropriately when they target this sparse probe data. Since for the sparser probe data of this range, it is required to check the reachability of the probe car between adjacent position fixes by using the Dijkstra's algorithm or A* algorithms. These algorithms, however, consume much computation power and can be a serious obstacle for map‐matching processing, especially in real‐time applications. The authors propose a new dynamic‐programming‐based map‐matching algorithm, which can also reduce the calculation time for the reachability test by introducing a hash algorithm. The results of the evaluation confirm the robustness and the effectiveness of the proposed algorithm in terms of both accuracy and computational performance.
Split‐ring‐resonator‐loaded multiband frequency agile slot‐based MIMO antenna system
Authors: Hussain Rifaqat , Khan Muhammad U. , Almajali Eqab , Sharawi Mohammad S.
Published: July 2019

In this work, a compact quad‐element multiple‐input‐multiple‐output (MIMO) antenna system is proposed. The design consists of four annular slot‐line based MIMO elements, printed on a commercially available RO4350 substrate with a total size of . Each annular slot has a rectangular slot inside it to increase its electrical length to further bring down the resonance frequency. Furthermore, a T‐shaped defected ground structure is utilised to increase the isolation between the closely spaced antenna elements. Each element is loaded with a unique split ring resonator (SRR), which results in size reduction as well as multi‐band operation covering 1.7–2.28, 2.35–2.85 and 2.9–3.1 GHz. Moreover, by using only a single varactor diode per element, fine frequency tuning over these bands is achieved. A wide frequency sweep over multi‐band and a peak gain of 2.95 dBi with 82% maximum radiation efficiency is achieved. Low envelope correlation coefficient values are observed throughout the operating band, thus offering good MIMO performance. The overall planar antenna design is compact, low‐profile and can easily be integrated with radio frequency front ends in second generation cognitive radios among many other applications.
Energy management and power quality enhancement in grid‐tied single‐phase PV system using modified PUC converter
Authors: Sahli Abdeslem , Krim Fateh , Laib Abdelbaset , Talbi Billel
Published: July 2019

Pack U‐Cell (PUC) multi‐level inverter is an attractive topology which widely investigated in the past few years for renewable energy conversion systems. This study introduces a modified five‐level packed Unit‐cell converter (MPUC5) for single‐phase double stage grid‐tied photovoltaic (PV) system with unity power factor. The proposed system operates as a single‐phase active power filter able to compensate reactive power generated by non‐linear loads connected to the point of common coupling, feeds the non‐linear load by the generated PV power, and injects the extra power into the grid. The MPUC5 inverter has a special topology with two DC‐link capacitors and six switches. One DC‐link of the inverter is connected to the PV arrays through DC/DC Cùk converter to draw the maximum power. Therefore, finite‐control‐set model predictive control (FCS‐MPC) for such configuration appears as a promising alternative for this inverter to work properly. Where the proposed FCS‐MPC algorithm is designed to ensure a high grid current quality, taking into consideration the issue of the capacitor voltages balancing and the switching frequency minimisation. Both simulation results and experimental validation through real‐time hardware in the loop system prove the validity and feasibility of the proposed control scheme, regarding PV power management and quality enhancement.
Improved plug–play SV with virtual inertia for enhancing the stability of high RES‐penetrated grids
Authors: Elshenawy Mahmoud Awad , Abdelkader Sobhy Mohamed , Amin Abdelrahman Ahmed , Farghal Soliman Ahmed
Published: July 2019

The synchronverter (SV) is currently one of the most promising grid‐friendly inverters that mimic synchronous generators (SGs). Almost all the available SV use virtual current signal for synchronization, which require a complicated controller that lacks plug–play capability. This paper proposes a new generation of self‐synchronised SV with a simpler controller, which provides plug–play capability with no need for switching between actual controller current and a virtual current for each ON–OFF process. The proposed SV (PSV) can also share the load with other SGs and SVs and also it is able to take part in regulating system frequency and voltage. A linearised small‐signal model is derived for the controller to investigate its stability. The PSV is also validated through multiple simulation studies carried out in MATLAB/Simulink environment. The results show the capability of the PSV to achieve self‐synchronisation and plug–play operation without a dedicated PLL or a virtual current. Compared to the current self‐synchronised SV, the PSV guarantees a smoother grid connection and gives more accurate reactive power sharing. Moreover, the PSV is applied to a modified IEEE 14‐bus test system considering three different contingencies to prove its impact on enhancing system dynamics and stability.
Optimal agency contract for incentive and control under moral hazard in dynamic electric power networks
Authors: Wasa Yasuaki , Hirata Kenji , Uchida Kenko
Published: July 2019

The authors propose an optimal contract mechanism under moral hazard in discrete‐time dynamic electric power networks. As the utility (system operator) cannot adjust the control input of the agents (end‐users) directly in real time out of respect for individual decision–making, the agents’ control input maximising their own profit does not always maximise social welfare. To avoid the issue, the authors introduce an aggregator as intermediary between the utility and the agents. The aggregator pays compensation for defective ancillary services, which are caused by random disturbance and the agents’ voluntary control. To reduce the compensation risk, the authors first present an optimal incentive/control contract problem for the aggregator's compensation. The problem is usually regarded as a principal‐agent problem under moral hazard in contract theory. However, it is generally difficult to solve a contract problem with dynamics expressed as discrete‐time simultaneous Bellman equations and a hierarchical control structure as a Stackelberg game. The authors next show that the problem can be solved by regarding it as a linear‐exponential‐quadratic‐Gaussian dynamic game and employing a numerical optimisation technique. Due to the ex‐ante appropriate payment contract, the agents select control inputs preferable for the aggregator. The effectiveness of the proposed contract mechanism is finally demonstrated through simulation.
Feasibility analysis of heterogeneous energy storage technology for cloud energy storage with distributed generation
Authors: Nagill N. , Reddy K. S. , Kumar R. , Panigrahi B.K.
Published: July 2019

Fluctuations of electricity prices in demand response schemes and intermittency of renewable energy supplies necessitate the adoption of energy storage in power systems. This paper considers the heterogeneous cloud energy storage (HCES) on cloud energy storage operator side. The goal of this approach is to lower the cost of energy storage by exploiting the different operating characteristics and economics of different battery energy storage technologies. The customers are screened from the type of storage facility that they have purchased and cloud energy storage (CES) operator can maximize the benefit if the complementarily of the storage technologies can be utilized. Distributed generation such as photo‐voltaic (PV) generation has also been considered on both side consumer as well as CES operator side for supplying power to energy storage facilities to reduce the cost of charging power. Furthermore, the paper also presents an economic viability of heterogeneous storage system using investment analysis methods. Numerical simulations are carried out based on HCES technological characteristics such as self discharge, round trip charge‐discharge cycle efficiency, depth of discharge (DOD) and cycles life time. There is significant changes in the economic performances using HCES when compared with single energy storage.
An intelligent methodology to improve distribution system operational parameters utilising smart inverter functionalities of PV sources
Authors: Verma Aprajay , Verma Pranjal Pragya , Eluvathiangal Anoop V , Swarup K. Shanti
Published: July 2019

The addition of distributed PV sources to low voltage distribution networks instigate issues to various operational parameters of the network. With modern smart inverters having controllable settings for voltage and power injection these issues can be alleviated. An Intelligent method utilising smart inverter functionalities of a PV source in a distribution network is proposed in present work to minimise, the power import from the grid, reduce network losses and minimise the magnitude of voltage violation. The optimal settings depend on load and generation variables. In order to reduce computational complexity, a scenario‐based method is used to handle these stochastic components in the system. A Non‐Sorted Genetic Algorithm (NSGA) is used for optimising the smart inverters parameters. The proposed scheme is envisaged to be realised by a Distribution Management System (DMS) which measures and coordinates all the smart inverters within the distribution feeder.
Improved hybrid scrubbing scheme for spaceborne static random access memory‐based field programmable gate arrays
Authors: Li Yue , Chen Zhichun , Shen Yuyao , Wang Yongqing
Published: July 2019

With the shrinking feature sizes of static random access memory‐based field programmable gate arrays (FPGAs), the occurrence probability of multiple‐cell upsets (MCUs) in FPGAs continues to increase. This reduces the reliability of FPGAs. This article proposes an improved hybrid scrubbing scheme to solve this problem. Based on the conventional hybrid scrubbing scheme, the error detection process is improved by changing the error correction object from an erroneous frame to an erroneous zone. MCUs can be rapidly corrected through continuous error detection and erroneous zone correction. The theoretical analysis and implementation results show that the improved hybrid scrubbing scheme can effectively reduce the average repair time of MCU errors.
Unified ZVS strategy for DAB with triple‐phase‐shift modulation in boost mode
Authors: Qiu Jian , Shen Kai , Tong Anping , Hang Lijun , Liao Jiarui
Published: July 2019

In this study, the switching mode and working waveform of dual active bridge (DAB) converter under triple phase‐shift modulation scheme is analysed, and an ALL‐ZVS (zero voltage switching) control strategy of all devices for full‐power range with voltage transfer ratio M  > 1 is proposed. First, a feasible control domain of ALL‐ZVS is derived by analysing the constraints of the control variables of ZVS for all switching devices under different operating modes. On this basis, an ALL‐ZVS control strategy of current RMS quasi‐optimisation under the condition of M  > 1 is proposed with the existing inductor current RMS optimisation control algorithm. It can be concluded that the proposed control strategy not only eliminates the switching loss, but also reduces the conduction loss, greatly improves the efficiency of the DAB converter. Finally, an experimental platform is built, and the experimental results verify the correctness and effectiveness of the proposed control strategy.
Cascaded Kalman filter for target tracking in automotive radar
Authors: Li Yang , Liang Can , Lu Man , Hu Xueyao , Wang Yanhua
Published: July 2019

In automotive anti‐collision radar system, the accuracy of velocity is one of the key indicators to measure radar performance. For frequency modulation continuous wave radar with chirp sequence, which is commonly used in automotive radar, there are two problems that are velocity ambiguity and measurement error. In order to address these problems, a cascaded Kalman filter algorithm is proposed in this article, which is able to overcome velocity ambiguity and improve the accuracy of measurements. In addition, the problem of velocity ambiguity can be solved just in the data processing and it avoids transmitting staggered or multiple pulse repetition frequency signal. The simulation results show that this algorithm can effectively improve the tracking performance.
Measurement of iron mass in concrete wall using ultra‐wide band radar
Authors: Kocadag Fatih , Firat Cinar Ridvan , Demirkol Askin
Published: July 2019

Here, it is aimed to measure and detect the iron mass of a concrete solid wall, column, floor by using of ultra‐wide band radar. Electromagnetic waves boundary conditions, reflection, and refraction of waves that radiate in solid material are analysed. GPR imaging methodology and scanning types such as A, B, and C are analysed. Ultra‐wide band radar imaging is used for detecting measuring the diameter of the iron material.
Feature‐enhanced SAR imaging algorithm based on attributed scatttering centre models for man‐made radar targets
Authors: Duan Jia , Wu Yifeng , Cao Lanying
Published: July 2019

Traditional synthetic aperture (SAR) imaging methods assume that man‐made targets are composed of point‐based scattering centres. In this way, gaps of components may be resulted, because of neglecting their inherent scattering behaviours. In order to enhance the integrity of components in SAR, a feature‐enhanced (FE) imaging method for SAR is proposed, taking into account the inherent behaviours of components of radar targets. Here, the radar echo is decomposed into attributed scattering centres (ASCs) instead of traditional point scattering centres. Based on the decomposed ASCs, different feature enhancement schemes are applied to different kinds of scattering centres according to their attributed parameters. As a result, a FE imaging image for SAR can be achieved by utilising the inherent feature of each decomposed ASCs.
Adaptive digital beamformer intellectual property based on high‐level synthesis
Authors: Zhu Shengxiang , Zhang Jinchang , He Zhiyi , He Min
Published: July 2019

Adaptive digital beamformer (ADBF) is effective in suppressing unexpected interferences arriving at the antenna array. An ADBF intellectual property (IP) using the floating point data type has been developed with high‐level synthesis (HLS) technology. This IP computes the real‐time adaptive weights of each sub‐array to spatially filter the arriving signals. The design has been validated in a recent airborne flight test and the result demonstrated the effectiveness of this approach.
Moving target modelling and indication in MIMO GEO SAR
Authors: Cui Chang , Liu Xiangrong , Dong Xichao , Hu Cheng , Li Yuanhao
Published: July 2019

Multiple‐input multiple‐output geosynchronous synthetic aperture radar (MIMO GEO SAR), composed by several mini‐satellites in GEO orbits, has more spatial degrees of freedom, which helps to suppress clutter and improves the performance of ground moving target indication (GMTI). However, in order to ensure the satellite safety, the satellite spacing in MIMO GEO SAR is very large. It results in the failure of far‐field assumption and causes the moving target defocusing because of the mismatch between the steering vector in far‐field sources and the moving target echo. Here, a new signal model based on the near‐field sources is first given according to the GEO SAR satellite‐ground geometry relationship. Then, considering the phase difference between the different channels, the spatial steering vector is derived and the weight vector for adaptive processing is proposed to suppress clutter and indicate the moving target. Finally, computer simulations are carried out for the validation of the proposed method.
Localisation of unresolved targets with frequency divers array radar
Authors: Wang Shengbin Luo , Xu Zhenhai , Liu Xinghua , Dong Wei , Wang Guoyu
Published: July 2019

The results of angular and range estimation by conventional signal processing will be far away from true values in the case of unresolved targets due to the merged measurement. In this article, the authors propose a method to localise unresolved targets for frequency diverse array (FDA) radar. Adopting the configurations of subarray‐based FDA and full‐band FDA as transmitter and receiver, the transmit and receive beampatterns of system are both decoupled in range and angle demands. Furthermore, the receive beamwidth is only a quarter of transmit in range. With the wide transmit beam and narrow receive beam, the authors divide the resolution cell containing unresolved targets into four parts to process separately. A method of intra‐pulse beam scanning is proposed to suppress the interference from the targets out of receive beam. Several simulation results demonstrate the effectiveness of the proposed method in the localisation of unresolved targets.
Kalman filter aided target density function for radar imaging
Authors: Cinar Ridvan Firat , Kocadag Fatih , Demirkol Askin
Published: July 2019

This study proposes a new algorithm for air target radar imaging by taking the geometrical and processing advantages of array antenna systems. The backscattered signal is processed with a new technique to benefit the facilities of angular scanning. In order to virtually increase the number of the radar elements of the array system, a powerful optimal estimator is employed, namely Kalman filter.
Educational data mining for students' performance based on fuzzy C‐means clustering
Authors: Li Yu , Gou Jin , Fan Zongwen
Published: July 2019

Education greatly aids in the process of students' growth; therefore, education institutions try to provide high‐quality education to their students. A possible remedy to provide high‐quality education is by discovering knowledge from educational data. However, accurately evaluating students' performance is very challenging due to different sources and structures of educational data. In addition, different teaching strategies are required because students' learning ability are different. One way to discover the hidden knowledge from educational data is the use of clustering algorithms, which are capable of mining interesting patterns from educational data. Thus, this study presents a fuzzy C‐means clustering algorithm using 2D and 3D clustering to evaluate students' performance based on their examination results (the examination grades from College of Computer Science and Technology, Huaqiao University for students enrolled in year 2014). Based on the experimental results from 2D and 3D clustering for evaluating students' performance, the educators can better understand the students' performance so as to build a pedagogical basis for decisions. Students can also receive some recommendations from the mining results about their performance.
Elemental abundances in the remnant of the ancient eruption of CK Vulpeculae
Authors: Tylenda R. , Kamiński T. , Mehner A.
Published: July 2019

CK Vulpeculae or Nova 1670 is an enigmatic eruptive object which underwent a stellar-merger event recorded by seventeenth-century observers. Its remnant was recently recovered at submillimeter wavelengths, revealing gas of an extraordinary isotopic composition indicative of past processing in the CNO cycles and partial He burning. Here, we present long-slit optical spectra of the remnant acquired with X-shooter at the Very Large Telescope (VLT) at an unprecedented sensitivity and spectral coverage. The spectra cover features of key elements, including H, He, C, N, and O, at ionization degrees I–III. A classical analysis of the spectra allowed us to identify several spatio-kinematic components in the probed part of the nebula at electron temperatures of 10–15 kK and densities of 200–600 cm−3. We find that the nebula is most likely excited by shocks rather than by direct radiation of the stellar remnant. We provide a detailed analysis of the elemental abundances in the remnant and find that helium is two times more abundant than in the Sun. Nitrogen is also overabundant with a N/O ratio ten times larger than the solar one. These anomalous abundances strongly indicate that the observed gas was processed in CNO cycles of H burning, consistent with the submillimeter studies. Additionally, sub-solar abundances of heavier elements, such as Ne, S, and Ar, suggest that the progenitor of CK Vul was formed from material poorer in metals than the Sun and was, therefore, an old stellar system before the 1670 eruption.
Neutral carbon and highly excited CO in a massive star-forming main sequence galaxy at z = 2.2
Authors: Brisbin Drew , Aravena Manuel , Daddi Emanuele , Dannerbauer Helmut , Decarli Roberto , González-López Jorge , Riechers Dominik , Wagg Jeff
Published: July 2019

We used the Plateau De Bure Interferometer to observe multiple CO and neutral carbon transitions in a z = 2.2 main sequence disk galaxy, BX610. Our observation of CO(7-6), CO(4-3), and both far-infrared (FIR) [CI] lines complements previous observations of Hα and low-J CO, and reveals a galaxy that is vigorously forming stars with UV fields (Log(GG0−1) ≲ 3.25); although less vigorously than local ultra-luminous infrared galaxies or most starbursting submillimeter galaxies in the early universe. Our observations allow new independent estimates of the cold gas mass which indicate Mgas ∼ 2 × 1011 M⊙, and suggest a modestly larger αCO value of ∼8.2. The corresponding gas depletion timescale is ∼1.5 Gyr. In addition to gas of modest density (Log(n cm3) ≲ 3) heated by star formation, BX610 shows evidence for a significant second gas component responsible for the strong high-J CO emission. This second component might either be a high-density molecular gas component heated by star formation in a typical photodissociation region, or could be molecular gas excited by low-velocity C shocks. The CO(7-6)-to-FIR luminosity ratio we observe is significantly higher than typical star-forming galaxies and suggests that CO(7-6) is not a reliable star-formation tracer in this galaxy.
Fragmentation, rotation, and outflows in the high-mass star-forming region IRAS 23033+5951
Authors: Bosco F. , Beuther H. , Ahmadi A. , Mottram J. C. , Kuiper R. , Linz H. , Maud L. , Winters J. M. , Henning T. , Feng S. , Peters T. , Semenov D. , Klaassen P. D. , Schilke P. , Urquhart J. S. , Beltrán M. T. , Lumsden S. L. , Leurini S. , Moscadelli L. , Cesaroni R. , Sánchez-Monge Á. , Palau A. , Pudritz R. , Wyrowski F. , Longmore S.
Published: July 2019

Context. The formation process of high-mass stars (>8 M⊙) is poorly constrained, particularly the effects of clump fragmentation creating multiple systems and the mechanism of mass accretion onto the cores.

Aims. We study the fragmentation of dense gas clumps, and trace the circumstellar rotation and outflows by analyzing observations of the high-mass (~500 M⊙) star-forming region IRAS 23033+5951.

Methods. Using the Northern Extended Millimeter Array (NOEMA) in three configurations and the IRAM 30 m single-dish telescope at 220 GHz, we probe the gas and dust emission at an angular resolution of ~0.45′′, corresponding to 1900 au.

Results. In the millimeter (mm) continuum emission, we identify a protostellar cluster with at least four mm-sources, where three of them show a significantly higher peak intensity well above a signal-to-noise ratio of 100. Hierarchical fragmentation from large to small spatial scales is discussed. Two fragments are embedded in rotating structures and drive molecular outflows, traced by 13CO (2–1) emission. The velocity profiles across two of the cores are similar to Keplerian but are missing the highest-velocity components close to the center of rotation, which is a common phenomena from observations like these, and other rotation scenarios are not excluded entirely. Position–velocity diagrams suggest protostellar masses of ~6 and 19 M⊙. Rotational temperatures from fitting CH3CN (12K− 11K) spectra are used for estimating the gas temperature and thereby also the disk stability against gravitational fragmentation, utilizing Toomre’s Q parameter. Assuming that the candidate disk is in Keplerian rotation about the central stellar object and considering different disk inclination angles, we identify only one candidate disk as being unstable against gravitational instability caused by axisymmetric perturbations.

Conclusions. The dominant sources cover different evolutionary stages within the same maternal gas clump. The appearance of rotation and outflows of the cores are similar to those found in low-mass star-forming regions.
Anharmonicity in the mid-infrared spectra of polycyclic aromatic hydrocarbons: molecular beam spectroscopy and calculations
Authors: Lemmens A. K. , Rap D. B. , Thunnissen J. M. M. , Mackie C. J. , Candian A. , Tielens A. G. G. M. , Rijs A. M. , Buma W. J.
Published: July 2019

Aims. In this work we determine the effects of anharmonicity on the mid-infrared spectra of the linear polycyclic aromatic hydrocarbons (PAHs) naphthalene, anthracene, tetracene and pentacene recorded using the free electron laser FELIX.

Methods. Comparison of experimental spectra obtained under supersonic jet conditions with theoretically predicted spectra was used to show if anharmonicity explicitly needs to be taken into account.

Results. Anharmonic spectra obtained using second-order vibrational perturbation theory agree on average within 0.5% of the experimental frequencies. Importantly, they confirm the presence of combination bands with appreciable intensity in the 5–6 μm region. These combination bands contain a significant fraction of the IR absorption, which scales linearly with the size of the PAH. Detection and assignment of the combination bands are a preliminary indication of the accuracy of far-IR modes in our anharmonic theoretical spectra. Detailed analysis of the periphery-sensitive CH out-of-plane band of naphthalene reveals that there is still room for improvement of the VPT2 approach. In addition, the implications of our findings for the analysis of the aromatic infrared bands are discussed.
The Elusive Nitro-Functionalised Member of the IRMOF-9 Family
Authors: Conte Luke , Zhou Tian-You , Qazvini Omid T. , Liu Lujia , Turner David R. , Telfer Shane G. , Richardson Christopher
Published: July 2019

The solvothermal reaction of 2-nitro-[1,1′‐biphenyl]‐4,4′‐dicarboxylic acid (H2bpdcNO2) with Zn(NO3)2·6H2O in DMF solvent does not give a functionalised variant of IRMOF-9. Single-crystal X-ray diffraction analysis shows the major initial product of this reaction, WUF-21 (WUF=Wollongong University Framework), is a porous interpenetrated diamondoid metal–organic framework (MOF) with a secondary building unit that ‘doubly straps’ eight bridging bpdcNO2 ligands in a distorted tetrahedral shape around an unusual pentazinc core. A second porous MOF phase (WUF-23) containing a large and novel dodecazinc secondary building unit forms in the same reaction and eventually predominates in solutions containing formate anion, which arises from the hydrolysis of DMF. Doping the starting ligand with [1,1′‐biphenyl]‐4,4′‐dicarboxylic acid (H2bpdc) provides a facile way to grow nitro-functionalised IRMOF-9, hereafter denoted as WUF-22, where the dopant is carried through into the product. Activated WUF-22 is a microporous solid with an apparent Brunauer–Emmett–Teller (BET) surface area of 2497m2g−1, which matches well with geometric surface area calculations. The CO2 adsorption properties of WUF-22 are reported.
The allosteric mechanism of substrate-specific transport in SLC6 is mediated by a volumetric sensor
Authors: LeVine Michael V. , Terry Daniel S. , Khelashvili George , Siegel Zarek S. , Quick Matthias , Javitch Jonathan A. , Blanchard Scott C. , Weinstein Harel
Published: July 2019

Significance

The combination of molecular dynamics simulation, single-molecule imaging, and functional assays described here reveals a mechanism of substrate selectivity in the SLC6 family of neurotransmitter transporters. We show that the rotameric state of a volumetric sensor in the substrate binding site is allosterically coupled to conformational changes necessary for transport, and as a consequence, upon binding large substrates, the transporter becomes stabilized in an inactive, nontransporting state upon binding larger substrates. This mechanistic insight suggests the possibility that medically relevant SLC6 transporters may be targeted by inhibitors that specifically modulate this sensor.
Critical Assessment 34: Are χ (Hägg), η and ϵ carbides transition-phases relative to cementite in steels?
Authors: Bhadeshia H. K. D. H. , Chintha A. R. , Lenka S.
Published: July 2019

Hägg carbide (χ) is, during the tempering of carbon-rich martensite, referred to as a transition carbide which eventually gives way to cementite. However, there are Fe–C binary phase diagrams estimated using thermodynamic data, that define a low-temperature phase field where a mixture of Hägg carbide and ferrite is more stable than that of cementite and ferrite. In this scenario, it may be cementite which is the transition carbide. Evidence is presented here that the predominance of Hägg carbide over cementite in the circumstances described is unlikely to be correct based on historical and new observations. Literature data are also interpreted to show that η and ϵ-carbides are best regarded as transition-phases relative to mixtures of cementite and ferrite.
Consistent female preference for rare and unfamiliar male color patterns in wild guppy populations
Authors: Valvo Jennifer J , Rodd F Helen , Hughes Kimberly A
Published: July 2019

How genetic variation is maintained in ecologically important traits is a central question in evolutionary biology. Male Trinidadian guppies, Poecilia reticulata, exhibit high genetic diversity in color patterns within populations, and field and laboratory studies implicate negative frequency-dependent selection in maintaining this variation. However, behavioral and ecological processes that mediate this selection in natural populations are poorly understood. We evaluated female mate preference in 11 natural guppy populations, including paired populations from high- and low-predation habitats, to determine if this behavior is responsible for negative frequency-dependent selection and to evaluate its prevalence in nature. Females directed significantly more attention to males with rare and unfamiliar color patterns than to males with common patterns. Female attention also increased with the area of male orange coloration, but this preference was independent of the preference for rare and unfamiliar patterns. We also found an overall effect of predation regime; females from high-predation populations directed more attention toward males than those from low-predation populations. Again, however, the habitat-linked preference was statistically independent from the preference for rare and unfamiliar patterns. Because previous research indicates that female attention to males predicts male mating success, we conclude that the prevalence of female preference for males with rare and unfamiliar color patterns across many natural populations supports the hypothesis that female preference is an important process underlying the maintenance of high genetic variation in guppy color patterns.
Threatened habitat at Great Salt Lake: Importance of shallow-water and brackish habitats to Wilson’s and Red-necked phalaropes
Authors: Frank Maureen G , Conover Michael R
Published: July 2019

Great Salt Lake (GSL) is the largest hypersaline lake in North America and is the fall staging area for a high proportion of North America’s Wilson’s Phalaropes (Phalaropus tricolor) and Red-necked Phalaropes (Phalaropus lobatus). Unfortunately, diversion of freshwater for agriculture and development has decreased the size of GSL by 48%. To assess the potential impact of a smaller GSL on phalaropes, we collected data from 2013 to 2015 from sites where large, dense flocks of phalaropes congregated and sites where there were no phalaropes. At each site, we measured the densities of invertebrates that were preyed upon by phalaropes, including larval and adult brine flies (Ephydridae), adult brine shrimp (Artemia franciscana), chironomid larvae (Chironomidae), and corixid adults (Corixidae). Abiotic characteristics measured included water depth, water salinity, water temperature, wind speed, and benthic substrate. We analyzed high-salinity sites separately from low-salinity sites because they contained different invertebrates. High-salinity sites were in Carrington and Gilbert bays and were relatively deep (mostly <2 m). At the high-salinity sites, phalaropes exhibited a preference for sites with an abundance of adult brine flies and for microbialite substrates. The low-salinity sites were in Ogden and Farmington bays and were shallow (<1 m). At low-salinity sites, large phalarope flocks were more likely to occur at sites that were shallower, less saline, and had a high biomass of benthic macroinvertebrates. Our results indicate that physical features and prey availability are both important in determining phalarope habitat use at GSL. Phalaropes prefer to use shallower parts of GSL and brackish waters. These areas will be especially impacted by decreased freshwater inflow into GSL.
Neutrophil Extracellular Traps Induce Intestinal Damage and Thrombotic Tendency in Inflammatory Bowel Disease
Authors: Li Tao , Wang Chunxu , Liu Yingmiao , Li Baorong , Zhang Wujian , Wang Lixiu , Yu Muxin , Zhao Xinyi , Du Jingwen , Zhang Jinming , Dong Zengxiang , Jiang Tao , Xie Rui , Ma Ruishuang , Fang Shaohong , Zhou Jin , Shi Jialan
Published: July 2019

Background and Aims

Despite the presence of neutrophil extracellular traps [NETs] in inflamed colon having been confirmed, the role of NETs, especially the circulating NETs, in the progression and thrombotic tendency of inflammatory bowel disease [IBD] remains elusive. We extended our previous study to prove that NETs constitute a central component in the progression and prothrombotic state of IBD.

Methods

In all 48 consecutive patients with IBD were studied. Acute colitis was induced by the treatment of C57BL/6 mice with 3.5% dextran sulphate sodium [DSS] in drinking water for 6 days. Peripheral blood neutrophils and sera were collected from IBD patients and murine colitis models. Exposed phosphatidylserine [PS] was analysed with flow cytometry and confocal microscopy. Procoagulant activity was evaluated using clotting time, purified coagulation complex, and fibrin formation assays.

Results

We observed higher plasma NET levels and presence of NETs in colon tissue in patients with active IBD. More importantly, NETs were induced in mice with DSS colitis, and inhibition of NET release attenuated colitis as well as colitis-associated tumorigenesis. NET degradation through DNase administration decreased cytokine levels during DSS-induced colitis. In addition, DNase treatment also significantly attenuated the accelerated thrombus formation and platelet activation observed in DSS-induced colitis. NETs triggered PS-positive microparticle release and PS exposure on platelets and endothelial cells partially through TLR2 and TLR4, converting them to a procoagulant phenotype.

Conclusions

NETs exacerbate colon tissue damage and drive thrombotic tendency during active IBD. Strategies directed against NET formation may offer a potential therapeutic approach for the treatment of IBD.
A history of spine surgery predicts a poor outcome after hip arthroscopy
Authors: Feingold Jacob D , Heaps Braiden , Turcan Sava , Swartwout Erica , Ranawat Anil
Published: July 2019

This study compared patient reported outcomes scores (PROMs) between patients undergoing hip arthroscopy who have and have not had previous lumbar spine surgery. We aimed to determine if prior spine surgery impacts the outcome of hip arthroscopy. Data were prospectively collected and retrospectively reviewed in patients who underwent hip arthroscopy between 2010 and 2017. Twenty cases were identified for analysis and matched to a control group. Four PROMs were collected pre-operatively and between 6 months and 2 years post-operatively (mean 16.2 months): Modified Harris Hip Score (mHHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports (HOS-Sports) and the 33-item International Hip Outcome Tool (iHOT-33). Patients with previous spine surgery reported significantly worse (P-value <0.001) post-operative scores on all PROMs and smaller net changes on all PROMs with the difference on the mHHS (P-value 0.007), HOS-Sport (P-value 0.009) and iHOT-33 (P-value 0.007) being significant. Subsequent analyses revealed that the type of spine surgery matters. Patients with a spine fusion reported worse post-operative scores on all PROMs compared with patients with a spine decompression surgery with the difference on the mHHS (P-value 0.001), HOS-ADL (P-value 0.011) and HOS-Sport (P-value 0.035) being significant. Overall, patients with prior decompression surgery experienced considerable improvements from hip arthroscopy whereas patients with a prior spine fusion reported poor post-operative outcomes. Given these results, it is vital that hip preservation surgeons understand the impact of the lumbar spine on the outcome of hip arthroscopy.
ZC4H2 stabilizes RNF220 to pattern ventral spinal cord through modulating Shh/Gli signaling
Authors: Ma Pengcheng , Song Ning-Ning , Cheng Xiaoning , Zhu Liang , Zhang Qiong , Zhang Long long , Yang Xiangcai , Wang Huishan , Kong Qinghua , Shi Deli , Ding Yu-Qiang , Mao Bingyu
Published: July 2019

ZC4H2 encodes a C4H2 type zinc-finger nuclear factor, the mutation of which has been associated with disorders with various clinical phenotypes in human, including developmental delay, intellectual disability and dystonia. ZC4H2 has been suggested to regulate spinal cord patterning in zebrafish as a co-factor for RNF220, an ubiquitin E3 ligase involved in Gli signaling. Here we showed that ZC4H2 and RNF220 knockout animals phenocopy each other in spinal patterning in both mouse and zebrafish, with mispatterned progenitor and neuronal domains in the ventral spinal cord. We showed evidence that ZC4H2 is required for the stability of RNF220 and also proper Gli ubiquitination and signaling in vivo. Our data provides new insights into the possible etiology of the neurodevelopmental impairments observed in ZC4H2-associated syndromes.
Automated Localization and Segmentation of Mononuclear Cell Aggregates in Kidney Histological Images Using Deep Learning
Authors: Lituiev Dmytro S. , Cha Sung Jik , Chin Aaron , Glicksberg Benjamin S. , Bishara Andrew , Dobi Dejan , Cheng Ruizhe (Ryan) , Sohn Jae Ho , Laszik Zoltan , Hadley Dexter
Published: July 2019

Allograft rejection is a major concern in kidney transplantation. Inflammatory processes in patients with kidney allografts involve various patterns of immune cell recruitment and distributions. Lymphoid aggregates (LAs) are commonly observed in patients with kidney allografts and their presence and localization may correlate with severity of acute rejection. Alongside with other markers of inflammation, LAs assessment is currently performed by pathologists manually in a qualitative way, which is both time consuming and far from precise. Here we present the first automated method of identifying LAs and measuring their densities in whole slide images of transplant kidney biopsies. We trained a deep convolutional neural network based on U-Net on 44 core needle kidney biopsy slides, monitoring loss on a validation set (n=7 slides). The model was subsequently tested on a hold-out set (n=10 slides). We found that the coarse pattern of LAs localization agrees between the annotations and predictions, which is reflected by high correlation between the annotated and predicted fraction of LAs area per slide (Pearson R of 0.9756). Furthermore, the network achieves an auROC of 97.78 ± 0.93% and an IoU score of 69.72 ± 6.24 % per LA-containing slide in the test set. Our study demonstrates that a deep convolutional neural network can accurately identify lymphoid aggregates in digitized histological slides of kidney. This study presents a first automatic DL-based approach for quantifying inflammation marks in allograft kidney, which can greatly improve precision and speed of assessment of allograft kidney biopsies when implemented as a part of computer-aided diagnosis system.