bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental analysis of the strands breaking characteristics of optical fibre composite overhead ground wire due to simulating lightning strike
Authors: Cai Li , Han Tianxi , Wang Jianguo , Xue Jian , Xu Fei , Zhou Mi , Fan Yadong
Published: April 2020

With the increasing application of OPGW (optical fibre composite overhead ground wire) in power systems, the strands in OPGW are frequently broken due to lightning strikes. In this study, ten kinds of OPGW lightning‐strike tolerance was tested according to the IEC standards. The influences of the following factors, such as transfer charge, tensile force, the diameter and material of OPGW outer layer strands, were analysed. The transfer charge and tensile force are positively proportional to the degree of lightning strike damage to OPGW. The diameters of OPGW outer layer strands are positively related to the lightning strike tolerance of OPGW. Compared with OPGW with aluminium alloy outer layer strands, lightning strikes tolerance of OPGW with aluminium clad steel (AS) outer layer strands is better. It suggested that the OPGW outer layer strands diameter >3.2 mm and with AS outer‐layer strands shows good lightning strike tolerance. The mechanism of OPGW strands breaking was also analysed by the infrared detection, micro‐morphology detection and energy spectrum. The experimental results of this study provide significant data support for OPGW type selection for lightning protection.
Modelling of inter‐area angular dynamics and proactive defence strategy in deregulated power grids with large‐scale integration of renewable energy sources
Authors: Mohamed Najda Vadakkeveettil , Pathirikkat Gopakumar , Rajan Sunitha
Published: April 2020

Power grid restructuring together with the integration of inertia less uncertain renewable generation, has resulted in depletion of inherent primary frequency response in the grid. Characterisation of inter‐area dynamics under uncertain generation and requisite reserve deployment strategies are not very well dealt with in the literature. Uncertainties in deregulated market demand proactive defence strategies to ensure stable and reliable power to consumers. This work depicts the inter‐area oscillation dynamics and proposes a proactive reserve deployment strategy based on probabilistic forecast error modelling. The model of oscillatory dynamics of deregulated power grids is established based on forecast error. The developed model could deliver better insight to wide‐area angular dynamics of the power grid. Reserve index developed on prior knowledge of this angular dynamics and probabilistic renewable generation serves as a key input to proposed proactive reserve deployment strategy defending the probable angular oscillations. WSCC 9‐bus system and IEEE 39‐bus system are adopted to analyse inter‐area angular dynamics as well as validate proposed proactive defence strategies in maintaining the reliable and secure operation of a deregulated grid.
Vanishing point detection using the teaching learning‐based optimisation algorithm
Authors: López‐Martinez Alan , Cuevas Francisco J.
Published: April 2020

Within the computer vision field, estimating image vanishing points has many applications regarding robotic navigation, camera calibration, image understanding, visual measurement, 3D reconstruction, among others. Different methods for detecting vanishing points relies on accumulator space techniques, while others employ a heuristic approach such as RANSAC. Nevertheless, these types of methods suffer from low accuracy or high computational cost. To explore a different technique, this paper focuses on improving the efficiency of the metaheuristic search for vanishing points by using a recently proposed population‐based method: The Teaching Learning Based Optimisation algorithm (TLBO). The TLBO algorithm is a metaheuristic technique inspired by the teaching–learning process. In our method, the TLBO algorithm is used after a line segment detection, to cluster line segments according to their more optimal vanishing point. Thus, our algorithm detects both orthogonal and nonorthogonal vanishing points in real images. To corroborate the performance of our proposed algorithm, different comparison and tests with other approaches were carried out. The results validate the accuracy and efficiency of our proposed method. Our approach had an average computational time of1.42 seconds and obtained a cumulative focal length error of 1 pixel, and cumulative angular error of 0.1°.
Perceptual accessible image encryption scheme conjugating multiple chaotic maps
Authors: Barik Ram Chandra , Changder Suvamoy
Published: April 2020

In the recent decade, chaos‐based image encryption algorithms gained attention due to their pros and cons. The authors suggest one such algorithm of image encryption for different colour space using feed forward initial condition to pursue random permutation by combining 1D logistic map with a series of tent maps. The algorithm adds one more novel step to protect and encrypt binary image by concealing it within a cover grey image using bit‐plane decomposition methods. Sensitivity towards initial condition is shown using block division of image by applying a stream of random initial conditions to each block for encryption along with XOR operation which leads the key space high . For better performance analysis, the proposed scheme has been tested with many colour space images including a binary image. The proposed technique is more efficient with respect to time complexity and resistance to vulnerability aspects.
3D reconstruction of spine image from 2D MRI slices along one axis
Authors: Ghoshal Somoballi , Banu Sourav , Chakrabarti Amlan , Sur‐Kolay Susmita , Pandit Alok
Published: April 2020

Magnetic resonance imaging (MRI) is a very effective method for identifying any abnormality in the structure and physiology of the spine. However, MRI is time consuming as well as costly. In this work, the authors propose an algorithm which can reduce the time of MRI and thus the cost, with minimal compromise on accuracy. They reconstruct a three‐dimensional (3D) image of the spine from a sequence of 2D MRI slices along any one axis with reasonable slice gap. In order to preserve the image at the edges properly, they regenerate the 3D image by using a combination of bicubic and bilinear interpolation along the orthogonal axis. From the reconstructed 3D, they use a simple geometric method to slice out any possible location along any axis and get the information in that region. They have tested their algorithm on real data, and found that their algorithm reduces the time by 80%, with high internal data preservation accuracy of about 96%.
SAR multi‐target interactive motion recognition based on convolutional neural networks
Authors: Huan Ruo‐Hong , Ge Luo‐Qi , Yang Peng , Xie Chao‐Jie , Chi Kai‐Kai , Mao Ke‐Ji , Pan Yun
Published: April 2020

Synthetic aperture radar (SAR) multi‐target interactive motion recognition classifies the type of interactive motion and generates descriptions of the interactive motions at the semantic level by considering the relevance of multi‐target motions. A method for SAR multi‐target interactive motion recognition is proposed, which includes moving target detection, target type recognition, interactive motion feature extraction, and multi‐target interactive motion type recognition. Wavelet thresholding denoising combined with a convolutional neural network (CNN) is proposed for target type recognition. The method performs wavelet thresholding denoising on SAR target images and then uses an eight‐layer CNN named EilNet to achieve target recognition. After target type recognition, a multi‐target interactive motion type recognition method is proposed. A motion feature matrix is constructed for recognition and a four‐layer CNN named FolNet is designed to perform interactive motion type recognition. A motion simulation dataset based on the MSTAR dataset is built, which includes four kinds of interactive motions by two moving targets. The experimental results show that the recognition performance of the authors’ Wavelet + EilNet method for target type recognition and FolNet for multi‐target interactive motion type recognition are both better than other methods. Thus, the proposed method is an effective method for SAR multi‐target interactive motion recognition.
Retracted: Innovative approach for multimodal fusion recognition based feature extraction using band‐limited phase‐only correlation and discrete orthonormal Stockwell transform
Authors: Kavipriya A. , Muthukumar A.
Published: April 2020

Biometrics is the bureau of science that helps to measure the individual's features by utilising their behavioural and physiological characteristics. Since years ago biometric technology are contemplated to be a unique tool for other security purposes. Inauspicious biometrics, Ear recognition, and Finger Knuckle Print have been enchanted as a booming analysis with interests among several researchers in modern periods. It has an ample range of private and other law enforcement applications. A combination of multiple human attributes is authenticated and considered to be a competent strategy in case of a multimodal Personal authentication system. In this paper extracting the local and global features via the structure of the time‐frequency domain has been studied. This proposed scheme exploits the analysis of dual biometric modalities i.e. Ear and Finger Knuckle Print which are carried out at the stage of feature‐level fusion. The feature Extraction two biometric patterns are obtained by generating the Local and Global feature information that helps in refining the alignment of dual biometric images in matching i.e. Discrete Orth normal Stockwell Transform‐Ear recognition and Band Limited phase‐only correlation with Finger Knuckle Print. Experiment results conducted with these FKP and EAR are demonstrated in improving recognition of efficient accuracy.
Adaptive transitions for automation in cars, trucks, buses and motorcycles
Authors: Diederichs Frederik , Knauss Alessia , Wilbrink Marc , Lilis Yannis , Chrysochoou Evangelia , Anund Anna , Bekiaris Evangelos , Nikolaou Stella , Finér Svitlana , Zanovello Luca , Maroudis Pantelis , Krupenia Stas , Absér Andreas , Dimokas Nikos , Apoy Camilla , Karlsson Johan , Larsson Annika , Zidianakis Emmanouil , Efa Alexander , Widlroither Harald , Dai Mengnuo , Teichmann Daniel , Sanatnama Hamid , Wendemuth Andreas , Bischoff Sven
Published: April 2020

Automated vehicles are entering the roads and automation is applied to cars, trucks, buses, and even motorcycles today. High automation foresees transitions during driving in both directions. The driver and rider state become a critical parameter since reliable automation allows safe intervention and transit control to the automation when manual driving is not performed safely anymore. When the control transits from automation to manual an appropriate driver state needs to be identified before releasing the automated control. The detection of driver states during manual and automated driving and an appropriate design of the human–machine interaction (HMI) are crucial steps to support these transitions. State‐of‐the‐art systems do not take the driver state, personal preferences, and predictions of road conditions into account. The ADAS&ME project, funded by the H2020 Programme of the European Commission, proposes an innovative and fully adaptive HMI framework, able to support driver/rider state monitoring‐based transitions in automated driving. The HMI framework is applied in the target vehicles: passenger car, truck, bus, and motorcycle, and in seven different use cases.
W‐band flat lens antenna with compact size and broadband performance
Authors: Liu Shi Lin , Lin Xian Qi , Lan Jian Yu , He Xiao Bin
Published: April 2020

A broadband short‐length lens antenna operating in W band is presented in this study. The lens is composed of a dielectric host material with numerous variable square holes drilling on it, which is fabricated using the three‐dimensional printing method with high accuracy and low cost. Then, the lens is mounted directly on the end of a length‐shortened horn antenna, obtaining a compact lens antenna. Phase variations of the dielectric unit‐cell under different oblique incidences are taken into consideration while constructing the lens. Simulation results reveal that gain enhancement of about 1 dB is achieved compared with the designs using the conventional method. Effects of lens height on antenna radiation performances are also studied and the lens profile is reduced to half with little performances deterioration. For the total lens antenna, a maximum gain of 23.2 dBi is measured at 94 GHz, which reveals 7.4 dB gain enhancement compared with the feed source. The measured 1 and 3 dB gain bandwidths are 13.8 and 37.8%, respectively. The proposed lens antenna shows a profile reduction of 42.3% with respect to the optimum horn while exhibiting comparable gain performance within a broad frequency band.
All‐optical logic inverter for large‐scale integration in silicon photonic circuits
Authors: Datta Tanmoy , Sen Mrinal
Published: April 2020

A new device architecture of an all‐optical logic inverter (AOLI) has been proposed in this study. The AOLI functions based on stimulated Raman scattering (SRS) in silicon nanocrystal embedded slotted photonic crystal waveguide (SPCW). The operating power and footprint size of the proposed device have significantly been scaled down to ∼1.5 mW and , respectively, by combining the benefits of giant SRS gain of silicon nanocrystal and ultra‐high spatio‐temporal confinement of the SPCW. Cascadability of the proposed AOLI has been investigated using the maximum product criterion of the noise margin. The successful operation of the AOLI has been demonstrated for the repetition rate of the pulses as high as 100 Gbps. Finally, tolerance of performance of the design under different types of fabrication imperfections has also been calculated to establish its sustainability in a practical scenario.
Closed‐loop control of a single‐stage switched‐boost inverter in modified DC‐interconnected nanogrids
Authors: Maged Nourhan Ahmed , Ebrahim Essamudin A. , Abdel‐Rahim Naser , Bendary Fahmy
Published: April 2020

Switched‐boost inverter (SBI) is a single‐stage power converter suitable for interfacing between photovoltaic (PV) arrays and loads. Although, it has many advantages such as it's not requiring an expensive complex dead‐time circuitry, yet its duty ratio is limited between 0 and 0.5. This means that it has some difficulties in increasing both the DC‐link output voltage and its AC‐output voltage. So, most researchers proposed it for low‐voltage power applications or using with step‐up transformers. Accordingly, this study contributes towards improving the performance of the SBI for being used in the modified nanogrid within an open energy system. It introduces a novel approach closed‐loop control technique to overcome most of the inverter drawbacks. Also, it enhances both the DC‐link and the transformer‐less rated AC output voltages to a sufficient value suitable for feeding domestic loads. And in the same time, the proposed robust controller utilizes a hysteresis band for balancing between voltage stability and PV‐maximum power achievement. This research also includes a more sophisticated fast‐charging slow‐discharging control strategy for the battery energy management system that depends on a bidirectional buck‐boost converter. Test results ensure the robustness of the proposed controller against sensitivity, nonlinearity, and time‐variant parameters of the overall system.
Comparison of 2D and 3D compressible convection in a pre-main sequence star
Authors: Pratt J. , Baraffe I. , Goffrey T. , Geroux C. , Constantino T. , Folini D. , Walder R.
Published: April 2020

Context.A 1D description of stellar dynamics is at the basis of stellar evolution modeling. Designed to investigate open problems in stellar evolution, the MUltidimensional Stellar Implicit Code expands a realistic 1D profile of a star’s internal structure to examine the interior dynamics of a specific star through either 2D or 3D hydrodynamic simulations.

Aims.Extending our recent studies of 2D stellar convection to 3D stellar convection, we aim to compare 3D hydrodynamic simulations to identically set-up 2D simulations, for a realistic pre-main sequence star.

Methods.We compare statistical quantities related to convective flows including: average velocity, vorticity, local enstrophy, and penetration depth beneath a convection zone. These statistics were produced during stationary, steady-state compressible convection in the star’s convection zone.

Results.Our simulations confirm the common result that 2D simulations of stellar convection have a higher magnitude of velocity on average than 3D simulations. Boundary conditions and the extent of the spherical shell can affect the magnitude and variability of convective velocities. The difference between 2D and 3D velocities is dependent on these background points; in our simulations this can have an effect as large as the difference resulting from the dimensionality of the simulation. Nevertheless, radial velocities near the convective boundary are comparable in our 2D and 3D simulations. The average local enstrophy of the flow is lower for 2D simulations than for 3D simulations, indicating a different shape and structuring of 3D stellar convection. We performed a statistical analysis of the depth of convective penetration below the convection zone using the model proposed in our recent study (Pratt et al. 2017, A&A, 604, A125). That statistical model was developed based on 2D simulations, which allowed us to examine longer times and higher radial resolution than are possible in 3D. Here, we analyze the convective penetration in 3D simulations, and compare the results to identically set-up 2D simulations. In 3D simulations, the penetration depth is as large as the penetration depth calculated from 2D simulations.
KIC 8975515: A fast-rotating (γ Dor – δ Sct) hybrid star with Rossby modes and a slower δ Sct companion in a long-period orbit
Authors: Samadi-Ghadim A. , Lampens P. , Jassur D. M. , Jofré P.
Published: April 2020

Aims. KIC 8975515 is a double-lined spectroscopic binary system with hybrid nature. Regular monitoring with the échelle spectrograph HERMES show that both components have matching atmospheric properties (Teff ∼ 7400 K), and that one of them is a fast rotator (v sin i = 162 versus 32 km s−1). Our aim is to study the Kepler light curve in order to determine the frequencies of the pulsations, to search for regular spacing patterns in the Fourier spectrum, if any, and to discuss their origin in the context of binarity and fast rotation.

Methods. In this paper, we study the properties of the stellar pulsations based on a careful analysis of the Fourier spectrum. This was done by performing repeated frequency-search analyses with successive prewhitenings of all the significant frequencies detected in the spectrum. Moreover, we searched for regular period spacing among the g modes as well as frequency splitting among the g and p modes in frequency.

Results. In the low-frequency regime, one series of prograde g modes and four series of retrograde r modes, were detected. The r modes are well-distributed with respect to the harmonics of the rotational frequency of the fast-rotating star frot = 1.647 d−1. The dominant g mode is f2 = 2.37 d−1. The strongest p mode is f1 = 13.97 d−1. We identified two multiplets of regularly split p modes with the mean values of 0.42 d−1 and 1.65 d−1. In addition, we also identified a few incidences of mode coupling (between f1 and a g or r mode).

Conclusions. We detected five series of retrograde r and prograde g modes as well as two multiplets of p modes with rotational frequency splitttings related to both components of KIC 8975515. We identified the fast-rotating component as a hybrid pulsator with r modes, and the slowly-rotating component as a δ Sct pulsator.
Dynamic programming and feedback analysis of the two dimensional tidal dynamics system
Authors: Mohan Manil T.
Published: April 2020

In this work, we consider the controlled two dimensional tidal dynamics equations in bounded domains. A distributed optimal control problem is formulated as the minimization of a suitable cost functional subject to the controlled 2D tidal dynamics equations. The existence of an optimal control is shown and the dynamic programming method for the optimal control of 2D tidal dynamics system is also described. We show that the feedback control can be obtained from the solution of an infinite dimensional Hamilton-Jacobi equation. The non-differentiability and lack of smoothness of the value function forced us to use the method of viscosity solutions to obtain a solution of the infinite dimensional Hamilton-Jacobi equation. The Bellman principle of optimality for the value function is also obtained. We show that a viscosity solution to the Hamilton-Jacobi equation can be used to derive the Pontryagin maximum principle, which give us the first order necessary conditions of optimality. Finally, we characterize the optimal control using the adjoint variable.
Carrier concentration increase in OFETs with interface barrier and Fermi level difference
Authors: Liu Xueqiang , Kang Haobo , Yang Ran
Published: April 2020

It was found that interface barrier is beneficial to form accumulation heterojunction in organic semiconductor. A new theoretical model has been established with combined effect of interface barrier and EF level difference between p-type and n-type materials. The organic pn-heterojunction has been put forward in OFETs for further research, 2 nm perylene diimide (PDI) and its derivatives (PDI-1)/(PDI-2) are used as discontinuous films to modify pentacene OFETs. The accumulative effect will be further enhanced under the joint effect of interface barrier and greater EF level difference. With the downgrading of LUMO level for n-type materials, the hole concentration in pentacene was increased by 12.3 times, 36.9 times and 107.4 times respectively, and VT shifted from −6.90 V to −2.67 V, 0.64 V and 6.82 V, the OFETs performance have been optimized efficiently, and the devices can be converted from enhancement-mode to depletion-mode. The LUMO level of PDI-2 was pinned to the EF level of pentacene has been verified by employing the organic-organic interface energy level alignment (OOI ELA) theory. The dramatic increase of carrier concentration is theoretically revealed at both sides of pn-heterojunction.
Cryptosporidiosis in HIV-positive patients and related risk factors: A systematic review and meta-analysis
Authors: Ahmadpour Ehsan , Safarpour Hanie , Xiao Lihua , Zarean Mehdi , Hatam-Nahavandi Kareem , Barac Aleksandra , Picot Stephane , Rahimi Mohammad Taghi , Rubino Salvatore , Mahami-Oskouei Mahmoud , Spotin Adel , Nami Sanam , Baghi Hossein Bannazadeh
Published: April 2020

Cryptosporidiumis one of the major causes of diarrhea in HIV-positive patients. The aim of this study is to systematically review and meta-analyze the prevalence ofCryptosporidiumin these patients. PubMed, Science Direct, Google Scholar, Web of Science, Cochrane and Ovid databases were searched for relevant studies dating from the period of 1 January 2000 to 31 December 2017. Data extraction for the included studies was performed independently by two authors. The overall pooled prevalence was calculated and subgroup analysis was performed on diagnostic methods, geographical distribution and study population. Meta-regression was performed on the year of publication, proportion of patients with diarrhea, and proportion of patients with CD4 < 200 cells/mL. One hundred and sixty-one studies and 51,123 HIV-positive participants were included. The overall pooled prevalence ofCryptosporidiuminfection in HIV-positive patients was 11.2% (CI95%: 9.4%–13.0%). The pooled prevalence was estimated to be 10.0% (CI95%: 8.4%–11.8%) using staining methods, 13.5% (CI95%: 8.9%–19.8%) using molecular methods, and 26.3% (CI95%: 15.0%–42.0%) using antigen detection methods. The prevalence ofCryptosporidiumin HIV patients was significantly associated with the country of study. Also, there were statistical differences between the diarrhea, CD4 < 200 cells/mL, and antiretroviral therapy risk factors with Cryptosporidiosis. Thus,Cryptosporidiumis a common infection in HIV-positive patients, and safe water and hand-hygiene should be implemented to prevent cryptosporidiosis occurrence in these patients.
Entraînement aux compétences communicationnelles : évaluation d’un débriefing et analyse de son lien avec le sentiment d’efficacité personnelle et les attitudes d’étudiants en médecine
Authors: Givron Hélène , Desseilles Martin
Published: April 2020

Contexte :  Il a été montré que bien que la simulation soit un moyen efficace d’entraîner les compétences communicationnelles (CC), le débriefing peut avoir des effets délétères sur le sentiment d’efficacité personnelle (SEP) et les attitudes de certains étudiants.Buts :Nous avons implanté un entraînement aux CC auprès de nos étudiants en médecine. Nos objectifs sont : 1) faire évaluer la qualité du climat instauré par le formateur lors du débriefing de la séance de simulation ; 2) connaître le SEP et les attitudes des étudiants envers les CC après le débriefing et ; 3) voir s’il existe des corrélations entre ces variables et l’évaluation qui est faite du climat de débriefing.Méthodes :167 étudiants en troisième année de médecine ont répondu à un questionnaire en ligne clôturant la fin d’un entraînement aux CC. Ce questionnaire quantitatif investiguait leur perception quant à la qualité du climat du débriefing, leur SEP rétrospectivement rapporté avant et après l’entraînement et leurs attitudes.Résultats :Les résultats indiquent une augmentation du SEP à l’égard des CC après l’entraînement. En outre, des corrélations positives significatives ont été identifiées entre une évaluation favorable du climat de débriefing et des scores élevés d’amélioration de SEP et d’attitudes positives envers l’entraînement aux CC.Conclusion :Une évaluation favorable du climat de débriefing semble liée à des scores élevés de SEP et d’attitudes positives rapportés après l’entraînement. Cette étude exploratoire invite à s’intéresser davantage à ces variables (évaluation du débriefing, SEP, attitudes) et leur lien avec le transfert des CC entraînées vers la pratique.
Raking-ratio empirical process with auxiliary information learning
Authors: Albertus Mickael
Published: April 2020

The raking-ratio method is a statistical and computational method which adjusts the empirical measure to match the true probability of sets of a finite partition. The asymptotic behavior of the raking-ratio empirical process indexed by a class of functions is studied when the auxiliary information is given by estimates. These estimates are supposed to result from the learning of the probability of sets of partitions from another sample larger than the sample of the statistician, as in the case of two-stage sampling surveys. Under some metric entropy hypothesis and conditions on the size of the information source sample, the strong approximation of this process and in particular the weak convergence are established. Under these conditions, the asymptotic behavior of the new process is the same as the classical raking-ratio empirical process. Some possible statistical applications of these results are also given, like the strengthening of the Z-test and the chi-square goodness of fit test.
Radiomics Analysis of Multiparametric PET/MRI for N- and M-Staging in Patients with Primary Cervical Cancer
Authors: Umutlu Lale , Nensa Felix , Demircioglu Aydin , Antoch Gerald , Herrmann Ken , Forsting Michael , Grueneisen Johannes Stefan
Published: April 2020

Zielsetzung Ziel dieser Studie war die Evaluierung des prädiktiven Potenzials der Radiomics-Analyse zur Bestimmung des N- und M-Stadiums des primären Zervixkarzinoms anhand multiparametrischer 18F-FDG-PET/MRT-Bildgebung.

Material und Methoden 30 Patientinnen mit einem histologisch gesicherten, primären und therapienaiven Zervixkarzinom unterzogen sich einer multiparametrischen 18F-FDG-PET/MRT-Untersuchung unter Verwendung eines dedizierten Untersuchungsprotokolls des weiblichen Beckens. Nach Segmentierung der Primärtumoren wurden quantitative Bildparameter mittels der Radiomic-Image-Processing-Toolbox bestimmt. Insgesamt wurden 45 verschiedene quantitative Bildmerkmale jeweils anhand der T2-gewichteten TSE-Sequenzen, der nativen und kontrastmittelgestützten T1-gewichteten TSE-Sequenzen, der ADC-Map, verschiedenen Perfusionsparametern (Ktrans, Kep, Ve and iAUC) und den 18F-FDG-PET-Datensätzen für jeden Tumor extrahiert. Die statistische Analyse zur Bestimmung des N- und M-Stadiums erfolgte unter der Verwendung der Python 3.5 und Scikit-learn-Software-Bibliothek für maschinelles Lernen.

Ergebnisse Insgesamt zeigte sich eine höhere Genauigkeit zur Prädiktion des korrekten M-Stadiums im Vergleich zum N-Stadium. Zur Prädiktion des korrekten M-Stadiums zeigten sich unter der Verwendung von SVM und SVM-RFE zur Feature-Auswahl die besten Ergebnisse mit einer Sensitivität von 91 %, einer Spezifität von 92 % und einer Fläche unter der Kurve (AUC) von 0,97. Die höchste Genauigkeit für die Bestimmung des N-Stadiums erfolgte unter der Verwendung von RBF-SVM und MIFS zur Feature-Auswahl mit einer Sensitivität von 83 %, einer Spezifität von 67 % und einer Fläche unter der Kurve (AUC) von 0,82.

Schlussfolgerung Die Radiomics-Analyse von multiparametrischen PET/MR-Datensätzen ermöglicht eine präzise Prädiktion des M- und N-Stadiums von Patientinnen mit primärem Zervixkarzinom und könnte damit supportiv zur nichtinvasiven Tumor-Phänotypisierung und Patientenstratifizierung eingesetzt werden.

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Continuous-wave cavity ring-down polarimetry
Authors: Visschers Jim C. , Tretiak Oleg , Budker Dmitry , Bougas Lykourgos
Published: April 2020

We present a new cavity-based polarimetric scheme for highly sensitive and time-resolved measurements of birefringence and dichroism, linear and circular, that employs rapidly pulsed single-frequency continuous wave (CW) laser sources and extends current cavity-based spectropolarimetric techniques. We demonstrate how the use of a CW laser source allows for gains in spectral resolution, signal intensity, and data acquisition rate compared to traditional pulsed-based cavity ring-down polarimetry (CRDP). We discuss a particular CW-CRDP modality that is different from intensity-based cavity-enhanced polarimetric schemes as it relies on the determination of the polarization rotation frequency during a ring-down event generated by large intracavity polarization anisotropies. We present the principles of CW-CRDP and validate the applicability of this technique for the measurement of the non-resonant Faraday effect in solid SiO2 and CeF3 and gaseous butane. We give a general analysis of the fundamental sensitivity limits for CRDP techniques and show how the presented frequency-based methodology alleviates the requirement for high finesse cavities to achieve high polarimetric sensitivities and, thus, allows for the extension of cavity-based polarimetric schemes into different spectral regimes, but most importantly renders the CW-CRDP methodology particularly suitable for robust portable polarimetric instrumentations.
A collocation-based multi-configuration time-dependent Hartree method using mode combination and improved relaxation
Authors: Wodraszka Robert , Carrington Tucker
Published: April 2020

Although very useful, the original multi-configuration time-dependent Hartree (MCTDH) method has two weaknesses: (1) its cost scales exponentially with the number of atoms in the system; (2) the standard MCTDH implementation requires that the potential energy surface (PES) be in the sum-of-product (SOP) form in order to reduce the cost of computing integrals in the MCTDH basis. One way to deal with (1) is to lump coordinates into groups. This is mode combination (MC). One way to deal with (2) is to reformulate MCTDH using collocation so that there are no integrals. In this paper, we combine MC and collocation to formulate a MC collocation multi-configuration time-dependent Hartree (MC-C-MCTDH) method. In practice, its cost does not scale exponentially with the number of atoms, and it can be used with any general PES; the PES need not be an SOP and need not have a special form. No integrals and, hence, no quadratures are necessary. We demonstrate the accuracy and efficiency of the new method by computing vibrational energy eigenstates of methyl radical, methane, and acetonitrile. To do this, we use MC-C-MCTDH with a variant of improved relaxation, derived by evaluating a residual at points. Because the MC basis functions are multivariate, collocation points in multi-dimensional spaces are required. We use two types of collocation points: (1) discrete variable representation-like points obtained from (approximate) simultaneous diagonalization of matrices and (2) Leja points, which are known to be good interpolation points, determined from a generalized recipe suitable for any basis.
Medium-term impact of tillage and residue retention on soil physical and biological properties in dry-seeded rice–wheat system in north-west India
Authors: Dhaliwal Jashanjeet Kaur , Singh M. J. , Sharma Sandeep , Gupta Naveen , Kukal S. S.
Published: April 2020

Repeated puddling for rice cultivation and extensive tillage during wheat cultivation in the north-west of India has adversely affected soil health. Adoption of resource conservation technologies (RCTs) is required for long-term sustainability of conventional rice–wheat systems. However, the behaviour of these technologies is site-specific. A field study was conducted in 2016 to evaluate the medium-term impact of tillage and residue retention on soil physical and biological characteristics. Four treatments were imposed during 2011: conventionally-tilled (CT) rice followed by CT wheat all without residue retention (–M); zero-tilled (ZT) rice followed by ZT wheat and –M; CT rice followed by CT wheat and all with residue retention (+M); and ZT direct-seeded rice followed by ZT wheat and +M. In the surface layer (0–15 cm) of ZT, soil organic carbon (SOC) stock was higher by 15%, mean weight diameter (MWD) by 31.8% and bulk density (BD) by 4% compared to CT averaged across residue treatments. Irrespective of tillage, SOC stock was increased by 19% and MWD by 39% and BD decreased by 1.8% in +M compared with –M in the 0–15 cm soil layer. Infiltration rate was higher in +M than –M irrespective of tillage. Microbial biomass carbon, basal soil respiration and soil enzymatic activities were higher in ZT and +M than CT and –M respectively. Thus, medium-term adoption of RCTs such as ZT and residue retention enhanced soil physical and biological properties in this dry-seeded rice–wheat system. However, whether retaining wheat residue improves soil physical and biological properties requires further investigation.
Integrin ανβ3 modulates lipopolysaccharide-induced hyperpermeability in cardiac microvascular endothelial cells
Authors: Li Li , Rongfang Zhou , Junhai Zhen , Changqin Chen , Jing Yan
Published: April 2020

Previous studies suggest an association of cardiac microvascular endothelial cells (CMECs) hyperpermeability with sepsis-related cardiac injury. Our results showed that CMECs permeability was dependent upon concentration and time of lipopolysaccharides (LPS) stimulation. Integrin ανβ3 expression decreased after LPS stimulation. Pretreatment with anti-integrin ανβ3 antibody enhanced LPS-induced hyperpermeability. Upregulation of integrin ανβ3 decreased LPS-induced hyperpermeability. F-actin remodeling was enhanced after LPS stimulation and was inhibited by up-regulation of integrin ανβ3. Inhibition of Src or Rac1 reduced CMECs permeability after LPS stimulation, but there were no differences in the phosphorylation of Src and Rac1 when over-expressing or blocking integrin β3. After pretreatment with Src or Rac1 inhibitor, no significant difference was found in the expression of integrin ανβ3 in LPS-induced CMECs. These finding suggested that integrin ανβ3 overexpression decreased LPS-stimulated CMECS permeability by inhibition of cytoskeletal remodeling, but the mechanism might not be mediated via Src/Rac1 signaling.
Resistance training with blood flow restriction: Impact on the muscle strength and body composition in people living with HIV/AIDS
Authors: Alves Thiago Cândido , Santos André P. , Abdalla Pedro P. , Venturini Ana Cláudia R. , Angelotti Priscila S. , Borges Franciane Góes , Reis Henrique D. O. , Bollela Valdes R. , Mota Jorge , Machado Dalmo R. L.
Published: April 2020

The aim of the study was to compare the impact of 12‐week resistance training with blood flow restriction (GRTBFR) versus, traditional resistance training (GTRT) and non‐training on the muscle strength and body composition HIV/AIDS participants. Muscle strength was tested at baseline, and on the 6th, 21st and 36th training sessions, using maximal repetition test. Pre‐ and post‐intervention body composition changes were measured by dual‐energy X‐ray absorptiometry. Resistance training was undertaken three times a week comprising bilateral elbow extension and flexion exercises, unilateral flexion and bilateral knee extension. Changes in strength and body composition (pre‐ and post‐intervention) between groups were evaluated by mixed models of repeated measures, and by paired and unpaired comparisons, considering the Effect Size. All groups were similar at baseline for muscle strength and body composition. Post‐intervention, the training groups showed similar, statistically significant increases in muscle strength (GRTBFR=25.7–57.4%; GTRT=24.5–52.3%) and skeletal muscle tissue (GRTBFR=8.4%; GTRT=8.3%). There was also a significant change in body fat (p=0.023–0.043), with significant effect sizes for strength and skeletal muscle tissue (0.41–2.27), respectively. These results suggest that both resistance training interventions promoted muscle hypertrophy, body fat reduction and positive impact on muscle strength in people living with HIV/AIDS. Resistance training with blood flow restriction proved to be an effective alternative to include patients with marked physical weakness, unable to engage in regular strength training programme.

ClinicalTrials.gov identifier: NCT02783417.
Adjusted parallel transport for higher gauge theories
Authors: Kim Hyungrok , Saemann Christian
Published: April 2020

Many physical theories, including notably string theory, require non-abelian higher gauge fields defining higher holonomy. Previous approaches to such higher connections on categorified principal bundles require these to be fake flat. This condition, however, renders them locally gauge equivalent to connections on abelian gerbes. For particular higher gauge groups, for example 2-group models of the string group, this limitation can be overcome by generalizing the notion of higher connection. Starting from this observation, we define a corresponding generalized higher holonomy functor which is free from the fake flatness condition, leading to a truly non-abelian parallel transport.
Magnetic exchange interactions in monolayer CrI3 from many-body
wavefunction calculations
Authors: Pizzochero Michele , Yadav Ravi , Yazyev Oleg V
Published: April 2020

The marked interplay between the crystalline, electronic, and magnetic structure of
atomically thin magnets has been regarded as the key feature for designing next-generation
magneto-optoelectronic devices. In this respect, a detailed understanding of the microscopic
interactions underlying the magnetic response of these crystals is of primary importance. Here,
we combine model Hamiltonians with multireference configuration interaction wavefunctions to
accurately determine the strength of the spin couplings in the prototypical single-layer magnet
CrI3. Our calculations identify the (ferromagnetic) Heisenberg exchange interaction
J = −1.44 meV as the dominant term, being the inter-site magnetic
anisotropies substantially weaker. We also find that single-layer CrI3 features an
out-of-plane easy axis ensuing from a single-ion anisotropy A = −0.10
meV, and predict g-tensor in-plane components

g

x
x

=

g

y
y

=
1.90

and out-of-plane component
g

zz
 = 1.92. In addition, we assess
the performance of a dozen widely used density functionals against our accurate correlated
wavefunctions calculations and available experimental data, thereby establishing reference
results for future first-principles investigations. Overall, our findings offer a firm
theoretical ground to recent experimental observations.
Influence of boric anhydride reinforcement on mechanical properties and abrasive wear of nylon 6
Authors: Randhawa Kawaljit Singh , Patel Ashwin D
Published: April 2020

To investigate the influence of boric anhydride (B2O3) on mechanical properties of nylon 6, tensile, hardness and impact test were carried out. Average tensile strength along with percentage elongation and modulus of elasticity has been calculated and plotted in this paper. Rockwell hardness and Izod impact tests were carried out to identify the hardness and toughness of materials. Boric anhydride used in this research was limited to less than 10 wt% of nylon 6 matrix material and was 2 wt%, 4 wt% and 8 wt%. Abrasion resistance of pure nylon 6 and composites was measured as weight loss due to abrasion. For the characterization of nylon 6 and its composites, Thermo-gravimetric analysis (TGA) and x-ray diffraction (XRD) were carried out. In results, it was found that the boric anhydride reinforcement increased the tensile strength and abrasion resistance when used up to 2 wt% in the nylon 6 matrix. Hardness found to be continually increased as the boric anhydride reinforcement percentage increased. The crystallinity of nylon 6 was little affected due to fillers and was found minimum for the 4 wt% boric anhydride reinforced nylon 6 composites. It was also found that the elastic modulus, Rockwell hardness and tensile strength, abrasion resistance show good correlations which are discussed in the discussion section.
Effect of different reduction rates on the near-interfacial structure of pressed 304/Q235 composite plate
Authors: Wang Shun , Zhao Guanghui , Li Yugui , Juan Li , Song Yaohui
Published: April 2020

The 304 stainless steel/Q235 composite plate was pressed at 1200 °C using a 500-ton hydraulic testing machine at a reduction rate of 25%, 30%, 35%, and 40% respectively. The microstructure of the composite plate was analyzed by means of scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The results showed that the black matter at the interface was the oxide of Mn and Si, and during the compression deformation process, the partial oxide film and the linear inclusions were crushed and extruded into fine particles. Small grains of different sizes appeared on the composite interface, and this deformation made the Q235 carbon steel and the 304 stainless steel on both sides of the composite interface show a coordinated deformation tendency when the reduction rate reached 35%. The whole process showed that the deformed carbon steel was first deformed, and the hard-to-deform stainless steel began to be deformed at a certain point, and then they were both further deformed together.
Structure and electronic properties of closed-ring defects in epitaxial graphene
Authors: Chen Yan , Li Meng-Chen , Wang Qi-Ming , Wang Guo-Sheng , Wei Xin , Song Guo-Feng , Kong Xiang-Mu , Xu Yun , Liu Ying
Published: April 2020

A number of past studies have focused on point and line defects in graphene epitaxially grown on SiC substrates. However, few studies have investigated closed-ring defects formed within grain boundary loops. The present study addresses this issue by applying low-temperature scanning tunneling microscopy/spectroscopy to investigate the atomic structures of closed-ring defects in graphene epitaxially grown on 4H-SiC, and to evaluate their effects on the electron state density. The results indicate that the orientations of the graphene lattice inside and outside of grain boundary loop structures are rotated uniformly by an angle of 30° relative to each other, suggesting that closed-ring defects are highly ordered and are mainly composed of clusters of pentagon-heptagon carbon rings and highly ordered pentagon-heptagon chains. In addition, the spectroscopy results reveal for the first time that the density of electron states inside a closed-ring defect is strongly localized and position-dependent. Moreover, these closed-ring defects can eliminate intervalley scattering while maintaining intravalley scattering. These findings are not only helpful for contributing to a deeper understanding of the effects of closed-ring defects in graphene, but also present a potentially useful valley-filtering mechanism for charge carries that can be applied to the practical development of all-electric valley-based devices.
Phase space analysis of quantum transport in electronic nanodevices
Authors: Datseris George , Fleischmann Ragnar
Published: April 2020

Electronic transport in nanodevices is commonly studied theoretically and numerically within the Landauer-Büttiker formalism: a device is characterized by its scattering properties to and from reservoirs connected by perfect semi-infinite leads, and transport quantities are derived from the scattering matrix. In some respects, however, the device becomes a ‘black box’ as one only analyses what goes in and out. Here we use the Husimi function as a complementary tool for quantitatively understanding transport in graphene nanodevices. It is a phase space representation of the scattering wavefunctions that allows to link the scattering matrix to a more semiclassical and intuitive description and gain additional insight in to the transport process. In this article we use the Husimi function to analyze some of the fascinating electronic transport properties of graphene, Klein tunneling and intervalley scattering, in two exemplary graphene nanodevices. By this we demonstrate the usefulness of the Husimi function in electronic nanodevices and present novel results e.g. on Klein tunneling outside the Dirac regime and intervalley scattering at a pn-junction and a tilted graphene edge.
Burkholder’s function and a weighted 𝐿² bound for stochastic integrals
Authors: Bañuelos Rodrigo , Brzozowski Michał , Osȩkowski Adam
Published: April 2020

Let

X
X

be a continuous-path martingale and let

Y
Y

be a stochastic integral, with respect to

X
X

, of some predictable process with values in

[
−
1
,
1
]

[-1,1]

. We provide an explicit formula for Burkholder’s function associated with the weighted

L
2

L^2

bound
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-vertical-bar upper Y double-vertical-bar Subscript upper L squared left-parenthesis upper W right-parenthesis Baseline less-than-or-equivalent-to left-bracket w right-bracket Subscript upper A 2 Baseline double-vertical-bar upper X double-vertical-bar Subscript upper L squared left-parenthesis upper W right-parenthesis Baseline period">

‖
Y

‖

L
2

(
W
)

≲
[
w

]

A
2

‖
X

‖

L
2

(
W
)

.

\begin{equation*} \|Y\|_{L^2(W)}\lesssim [w]_{A_2}\|X\|_{L^2(W)}. \end{equation*}
What might but must not be
Authors: Finlay Stephen , Lennertz Benjamin
Published: April 2020

We examine an objection to analysing the epistemic ‘might’ and ‘may’ as existential quantifiers over possibilities. Some claims that a proposition “might” be the case appear felicitous although, according to the quantifier analysis, they are necessarily false, since there are no possibilities in which the proposition is true. We explain such cases pragmatically, relying on the fact that ‘might’-sentences are standardly used to convey that the speaker takes a proposition as a serious option in reasoning. Our account explains why it makes sense to utter these sentences despite their being literally false and why their falsity is easily missed.