bluuebunny/crossref_metadata_2025_split huggingface dataset:
The impact of summer drought on peat soil microbiome structure and function-A multi-proxy-comparison
Authors: Wang Haitao , Meister Mareike , Jensen Corinna , Kuss Andreas W , Urich Tim 
Published: August 2022

Abstract
Different proxies for changes in structure and/or function of microbiomes have been developed, allowing assessing microbiome dynamics at multiple levels. However, the lack and differences in understanding the microbiome dynamics are due to the differences in the choice of proxies in different studies and the limitations of proxies themselves. Here, using both amplicon and metatranscriptomic sequencings, we compared four different proxies (16/18S rRNA genes, 16/18S rRNA transcripts, mRNA taxonomy and mRNA function) to reveal the impact of a severe summer drought in 2018 on prokaryotic and eukaryotic microbiome structures and functions in two rewetted fen peatlands in northern Germany. We found that both prokaryotic and eukaryotic microbiome compositions were significantly different between dry and wet months. Interestingly, mRNA proxies showed stronger and more significant impacts of drought for prokaryotes, while 18S rRNA transcript and mRNA taxonomy showed stronger drought impacts for eukaryotes. Accordingly, by comparing the accuracy of microbiome changes in predicting dry and wet months under different proxies, we found that mRNA proxies performed better for prokaryotes, while 18S rRNA transcript and mRNA taxonomy performed better for eukaryotes. In both cases, rRNA gene proxies showed much lower to the lowest accuracy, suggesting the drawback of DNA based approaches. To our knowledge, this is the first study comparing all these proxies to reveal the dynamics of both prokaryotic and eukaryotic microbiomes in soils. This study shows that microbiomes are sensitive to (extreme) weather changes in rewetted fens, and the associated microbial changes might contribute to ecological consequences.
Effect of photoionisation on initial discharge in air under nanosecond pulse voltage
Authors: Li Yutai , Fu Yangyang , Liu Zhigang , Li Handong , Wang Peng , Luo Haiyun , Zou Xiaobing , Wang Xinxin 
Published: August 2022

AbstractEffects of photoionisation on the development and electron runaway of the initial discharge in atmospheric air under nanosecond pulse voltage were studied via two‐dimensional particle‐in‐cell/Monte Carlo collision simulations. It was found that photoionisation has little effect at the beginning of the initial discharge. However, as the discharge channel gradually develops towards the anode, photoionisation shows greater impacts on the morphology of discharge but has little influence on the velocity of discharge development. Photoionisation does not appear to have a decisive effect on the growth trend of the highest energy of runaway electrons, but it does affect the change rate of the highest energy and overall distribution of electron energy, resulting in a higher proportion of energetic electrons. The difference in the distributions of the electron energy between the two cases, with and without considering photoionisation, can be attributed to the impact of photoionisation on the discharge morphology, which in turn distorted the electric field. The spatial density distributions of the electrons produced by photoionisation further explained the differences. The authors’ results explicitly demonstrate the influence of photoionisation on the development and the electron runaway of the initial discharge under nanosecond pulse voltage, which provides more comprehensive knowledge for the atmospheric air gap nanosecond pulse discharge physics.
Lock-in phenomenon in the wake flow past an oscillating circular nano-cylinder
Authors: Zhu Yanqi , Jin Hanhui , Guo Yu , Ku Xiaoke , Fan Jianren 
Published: August 2022

In this paper, the lock-in/synchronization phenomenon in the wake flow around an oscillating nano-cylinder is studied with molecular dynamics simulation. The results show that the lock-in valley of the velocity fluctuation also occurs in nano-scale. Similar to those in normal scales (usually &gt;1 mm), three regimes of lock-in, transition, and no-lock-in states are also obtained. Unlike in normal scales, the concurrence of the density and velocity fluctuation waves with different phase and the same frequency makes the fluctuation frequency of the lift force different from that of the velocity. The oscillation of the nano-cylinder can intensify the lift force fluctuation, especially in the lock-in state. The intensity of the lift force increases with the amplitude of the nano-cylinder vibration. The lock-in valley of the lift force usually covers a wider range of frequency than that of the velocity. Improving the inflow Reynolds number can reduce the coverage range of the lock-in valley in frequency. The lock-in valley does not vary apparently as the Jz number, which represents the interaction intensity between fluid molecules, increases until it approaches Jz ≈ 1.4. The rise of Kn number can promote the occurrence of the lock-in phenomenon.
Facile synthesis of core–shell structured C/Fe3O4 composite fiber electromagnetic wave absorbing materials with multiple loss mechanisms
Authors: Dai Bushi , Qi Yang , Song Mengjie , Zhang Bowen , Wang Nan , Dai Yuxiang 
Published: August 2022

The use of heterostructures in electromagnetic wave absorption applications has been limited by the problem of homogeneous dispersion in composites. In this study, three-dimensional (3D) cross-linked electromagnetic wave absorbing composites with the carbon nanofiber/Fe3O4 (CNF/Fe3O4) core–shell structure were synthesized by expanding the interface of the heterogeneous structure with Fe3O4 nanocrystals uniformly modified on the surface of the carbon nanofiber. The 3D cross-linked structure of the composites contributes to the generation of conductive loss and macroscopic eddy current loss. The heterogeneous interface formed by graphite nanocrystals and amorphous carbon in the carbon nanofiber is identified by high-resolution transmission electron microscopy and Raman spectroscopy as having a strong electromagnetic wave absorption capacity for boundary-type defects. The Fe3O4 nanocrystal particles on the surface of the carbon nanofiber not only have the strong magnetic loss capability of magnetic materials but also form a new heterogeneous interface with the carbon nanofiber surface, which further enhances the interfacial polarization of the composite and improves the electromagnetic wave absorption properties. With the synergistic effects of interfacial polarization, macroscopic and microscopic eddy current losses, conductive losses, and magnetic losses, the electromagnetic wave absorption performance of the composites is further enhanced based on the carbon nanofiber. The reflection loss reaches −51.11, −42.99, and −55.98 dB at 9, 12 (X-band), and 17 GHz (Ku-band), respectively, corresponding to the thicknesses of 2.0, 1.5, and 1.0 mm. In addition, the widest effective absorption bandwidth is 3.3 GHz at 14.7–18 GHz (only 1.09 mm).
A new perspective on ecological vulnerability and its transformation mechanisms
Authors: Hou Kang , Tao Wendong , He Dan , Li Xuxiang 
Published: August 2022

ABSTRACT
Ecological vulnerability refers to the degree of ecosystem disturbance, system damage, and the ability of system restoration. Although case-specific evaluations of ecological vulnerability are progressing rapidly, they have been carried out mainly in areas with intensive human activities or in harsh natural environments. Using the Web of ScienceTM core collection, this review paper summarized studies on ecological vulnerability published from 2000 to 2022 and analyzed in depth major case studies. It was found that traditional ecological vulnerability research has been addressed largely in terms of assessment models, data processing models, and analysis of influencing factors, however there was a lack of research on the process of vulnerability transformation. Because the vulnerability transformation in a hierarchical vulnerability index system is regulated by multiple factors in a heterogeneous region, it is urgent to understand how the ecological vulnerability in a region evolves from one level to another over time. Therefore this paper put forward the new perspective of research, i.e., applying quantitative analysis to identification of regulating factors and exploring the mechanisms of ecological vulnerability transformation. This new perspective could assist in monitoring the complex spatiotemporal changes in ecological vulnerability and taking necessary measures to prevent from decline of ecological stability.
Solution of an acoustic transmission inverse problem by extended inversion
Authors: Symes William W , Chen Huiyi , Minkoff Susan E 
Published: August 2022

Abstract
Study of a simple single-trace transmission example shows how an extended source formulation of full-waveform inversion can produce an optimization problem without spurious local minima (‘cycle skipping’), hence efficiently solvable via Newton-like local optimization methods. The data consist of a single trace extracted from a causal pressure field, propagating in a homogeneous fluid according to linear acoustics, and recorded at a given distance from a transient point energy source. The source intensity (‘wavelet’) is presumed quasi-impulsive, with zero energy for time lags greater than a specified maximum lag. The inverse problem is: from the recorded trace, recover both the sound velocity or slowness and source wavelet with specified support, so that the data is fit with prescribed RMS relative error. The least-squares objective function has multiple large residual minimizers. The extended inverse problem permits source energy to spread in time, and replaces the maximum lag constraint by a weighted quadratic penalty. A companion paper shows that for proper choice of weight operator, any stationary point of the extended objective produces a good approximation of the global minimizer of the least squares objective, with slowness error bounded by a multiple of the maximum lag and the assumed noise level. This paper summarizes the theory developed in the companion paper and presents numerical experiments demonstrating the accuracy of the predictions in concrete instances. We also show how to dynamically adjust the penalty scale during iterative optimization to improve the accuracy of the slowness estimate.
On the use of nonlinear anisotropic diffusion filters for seismic imaging using the full waveform
Authors: Métivier L , Brossier R 
Published: August 2022

Abstract
Nonlinear anisotropic diffusion filters have been introduced in the field of image processing for image denoising and image restoration. They are based on the solution of partial differential equations involving a nonlinear anisotropic diffusion operator. From a mathematical point of view, these filters enjoy attractive properties, such as minimum–maximum principle, and an inherent decomposition of the images in different scales. We investigate in this study how these filters can be applied to help solving data-fitting inverse problems. We focus on seismic imaging using the full waveform, a well known nonlinear instance of such inverse problems. In this context, we show how the filters can be applied directly to the solution space, to enhance the structural coherence of the parameters representing the subsurface mechanical properties and accelerate the convergence. We also show how they can be applied to the seismic data itself. In the latter case, the method results in an original low-frequency data enhancement technique making it possible to stabilize the inversion process when started from an initial model away from the basin of attraction of the global minimizer. Numerical results on a 2D realistic synthetic full waveform inversion case study illustrate the interesting properties of both approaches.
A new approach to COVID-19 detection from x-ray images using angle transformation with GoogleNet and LSTM
Authors: Kaya Yılmaz , Yiner Züleyha , Kaya Mahmut , Kuncan Fatma 
Published: August 2022

Abstract
Declared a pandemic disease, COVID-19 has affected the lives of millions of people and had significant effects on public health. Despite the development of effective vaccines against COVID-19, cases continue to increase worldwide. According to studies in the literature, artificial intelligence methods are used effectively for the detection of COVID-19. In particular, deep-learning-based approaches have achieved very good results in clinical diagnostic studies and other fields. In this study, a new approach using x-ray images is proposed to detect COVID-19. In the proposed method, the angle transform (AT) method is first applied to the x-ray images. The AT method proposed in this study is an important novelty in the literature, as there is no such approach in previous studies. This transformation uses the angle information created by each pixel on the image with the surrounding pixels. Using the AT approach, eight different images are obtained for each image in the dataset. These images are trained with a hybrid deep learning model, which combines GoogleNet and long short-term memory (LSTM) models, and COVID-19 disease detection is carried out. A dataset from the Mendeley database is used to test the proposed approach. A high classification accuracy of 98.97% is achieved with the AT + GoogleNet + LSTM approach. The results obtained were also compared with other studies in the literature. The presented results reveal that the proposed method is successful for COVID-19 detection using chest x-ray images. Direct transfer methods were also applied to the data set used in the study. However, worse results were observed according to the proposed approach. The proposed approach has the flexibility to be applied effectively to different medical images.
Gas distribution by EIT during PEEP inflation: PEEP response and optimal PEEP with lowest trans-pulmonary driving pressure can be determined without esophageal pressure during a rapid PEEP trial in patients with acute respiratory failure
Authors: Grivans Christina , Stenqvist Ola 
Published: August 2022

Abstract

Objective. Protective ventilation should be based on
lung
mechanics and transpulmonary driving pressure (ΔPTP), as this ‘hits’ the lung directly. Approach. The change in end-expiratory lung volume (ΔEELV) is determined by the size of the PEEP step and the elastic properties of the lung (EL), ΔEELV/ΔPEEP. Consequently, EL can be determined as ΔPEEP/ΔEELV. By calibration of tidal inspiratory impedance change with ventilator inspiratory tidal volume, end-expiratory lung impedance changes were converted to volume changes and lung P/V curves were obtained during a PEEP trial in ten patients with acute respiratory failure. The PEEP level where ΔPTP was lowest (optimal PEEP) was determined as the steepest point of the lung P/V curve. Main results. Over-all EL ranged between 7.0–23.2 cmH2O/L. Optimal PEEP was 12.9 cmH2O (10–16) with ΔPTP of 4.1 cmH2O (2.8–7.6). Patients with highest EL were PEEP non-responders, where EL increased in non-dependent and dependent lung at high PEEP, indicating over-distension in all lung. Patients with lower EL were PEEP responders with decreasing EL in dependent lung when increasing PEEP. Significance. PEEP non-responders could be identified by regional lung P/V curves derived from ventilator calibrated EIT. Optimal PEEP could be determined from the equation for the lung P/V curve.
Blob tracking and formation in edge and SOL plasmas using Q-factor
Authors: Bisai N , Sen A 
Published: August 2022

Abstract
We propose a direct means of identifying and tracking plasma blobs in the tokamak edge and scrape-off layer (SOL) regions through evaluation of a quantity Q that is a measure of the relative contribution from the square of the sheared strain and the square of the vorticity at any spatial location. The sheared strain and vorticity are related to the various velocity gradients in the plasma fluid. The blob formation from the breakup of a streamer structure can be determined from the criterion Q > 0. A blob is associated with a high negative value of Q that is indicative of a stable vortex flow of the local fluid trajectories. The validity of this criterion, obtained from a linear eigenvalue analysis of the stability of fluid trajectories, is supported by nonlinear fluid simulations that clearly identify blobs with regions where Q < 0 and exceeds a threshold value. The parameter Q can be experimentally determined from measurements of local electric field shears using gas puff imaging or Langmuir probe techniques, and the proposed criterion can provide a direct means of tracking plasma blobs. The rotation or spin of a blob in the edge and SOL regions can also be characterized by Q.
Applied method of characteristics on 2nd order linear P.D.E
Authors: Farg Ahmed Saeed , Abd Elbary A. M. , Khalil Tarek A. 
Published: August 2022

Abstract
PDEs are very important in dynamics, aerodynamics, elasticity, heat transfer, waves, electromagnetic theory, transmission lines, quantum mechanics, weather forecasting, prediction of crime places, disasters, how universe behave ……. Etc., second order linear PDEs can be classified according to the characteristic equation into 3 types hyperbolic, parabolic and elliptic; Hyperbolic equations have two distinct families of (real) characteristic curves, parabolic equations have a single family of characteristic curves, and the elliptic equations have none. All the three types of equations can be reduced to its first canonical form finding the general solution or the second canonical form similar to 3 basic PDE models; Hyperbolic equations reduce to a form coinciding with the wave equation in the leading terms, the parabolic equations reduce to a form modeled by the heat equation, and the Laplace’s equation models the canonical form of elliptic equations. Thus, the wave, heat and Laplace’s equations serve as basic canonical models for all second order linear PDEs.
Generalized thermoelastic in a fiber-reinforced medium with cylindrical cavity under G-N theory
Authors: Khader S E , Marrouf A A , Khedr M 
Published: August 2022

Abstract
The present paper is aimed at studying the wave propagation for a problem of cylindrical cavity. The material is assumed to be fiber-reinforced with increased stiffness, strength and load bearing capacity. Using generalized thermoelasticity theory, Green and Nagdhi, with and without energy dissipation. Laplace transform techniques are used to derive the solution in the Laplace transform domain. The inversion process is carried out using a numerical method based on Fourier series expansions. The results obtained are displayed by graphs to clear the phenomena physical meaning and compeer with generalized thermoelasticity theories.
Simulation of Ozone Concentrations Inside Co-60 Industrial Irradiator Using UV Optical Cell
Authors: El Gamel Amal , Noaman Ali 
Published: August 2022

Abstract
ozone concentration in the Co-60 industrial irradiator is controlled by the local exhaust ventilation (LEV). if the event of a ventilation malfunction, the ozone concentration becomes increasingly sensible within the radiation chamber. Ozone (O3) is a toxic gas which can cause tract, asthma, and permanent lung damage. its detrimental effects on humans and corrosion of metal parts within the radiation chamber indicates its importance as a safety factor consideration. The motivation for this work designs a standby system to reduce the ozone concentration within the Co-60 industrial radiator. MATLAB was used to simulate the effect of ultraviolet (254 nm) absorption cells on ozone concentration and calculate the decay time. The simulation illustrated that UV absorption is linearly increasing with increasing ozone concentration. Employing a UV Cell proved to reduce ozone concentrations and their decay time with an efficiency of 99%. This may prevent or significantly reduce the discharge of ozone into the air from the workplace. so it’s recommended that’s using UV (254 nm) in the ozone concentration within the Co-60 industrial as it is cheap and efficient controlling substance.
Utilization of INAA Technique for Studying the Negative Impact of Human Activities on Coral Reefs in the Quseir harbour area
Authors: Mohsen Mohamed Y.M. , El-Taher Atef , Shabib Mohamed , Mohamed Nader M. A. , Ashry H. A. , Abdel-Rahman Mohamed A.E. 
Published: August 2022

Abstract
Coral reef samples collected from the Egyptian Red Sea coast’s Quseir harbour were analysed using the INAA technique for qualitative and quantitative analysis. The concentration of heavy metals, rare earth elements, and elemental contents were measured in coral reefs. The samples were assembled with their standards and irradiated in Egypt’s Second Research Reactor at the same time (ETRR-2). The gamma-ray spectra of an HPGe detector with a 100 percent relative efficiency were studied. The elements determined are: Al, Ti, Na, K, Mg, V, Cl, Ca, Mn, Cr, As, Co, Zn, Fe, Br, Tb, Zr, Hf, Sb, Ba, Sc, Nd, La, Sm, Ce, Eu, Yb, Ta, U, and Th. The present work is worried about the use of INAA to attain an accurate knowledge about the elemental content in coral reef samples in the Quseir harbour area and revealing potential environmental indicators for heavy metals contamination as well as pollution hot spot throughout this area to assess the public health for workers, tourists, and the surrounding population.
A desktop study on fish assemblages in Malaysian lotic habitats
Authors: Cheok T N , Soo C L 
Published: August 2022

Abstract
A desktop study on freshwater fish in Malaysian lotic habitats was conducted to provide an overview of the freshwater fish assemblages in Malaysia. Secondary data was extracted from literature that retrieved from major scientific databases including Google Scholar, ScienceDirect, and SpringerLink. A total of 385 fish species from 49 families were documented in Malaysian lotic habitats based on secondary data analysis. The Cyprinidae family is the most abundant fish family in Malaysia with 88 species recorded, followed by Danionidae (44), Bagridae (27), and Osphronemidae (21). The Cyprinidae family has the top five fish species recorded most frequently in Malaysian lotic habitats, which are present in the majority of Malaysia’s states. Approximately 47% of fish species are restricted to just one state of Malaysia, demonstrating endemism of freshwater fish is high in Malaysian lotic habitats. Fish assemblages were found to be similar in Kedah, Kelantan, Pahang, Perak, Terengganu, and Johor, but very different in Sabah, Sarawak, Penang, Negeri Sembilan, and Selangor. Connectivity between lotic habitats in each state, land use, endemism, and invasive species may all influence the fish assemblages in each Malaysian state. This study revealed that ichthyofaunal research is lacking in several Malaysian states. More research should be done in those states to fill in the research gaps and present the most up-to-date information on Malaysia’s ichthyofaunal study.
The SIR Model for COVID-19 in Malaysia
Authors: Zenian S 
Published: August 2022

Abstract
In March 2020, the World Health Organization (WHO) declared COVID-19 as a global pandemic caused by severe acute respiratory syndrome. This virus is referred to as SARS-CoV-2 and the associated disease is COVID-19. It is an infectious disease that can easily be transmitted via respiratory droplets through direct or indirect contact. This paper presents an epidemiological model of COVID-19 in Malaysia by using Susceptible-Infected-Removed (SIR) as a forecasting model. Forecasting is a technique used to predict or estimate the trend or rate of change for future events. This method can provide a good forecasting result for evaluating public health and social measures in response to the COVID-19 epidemic and also to make timely plans.