bluuebunny/crossref_metadata_2025 huggingface dataset:
Delamination model of an epoxy-impregnated REBCO superconducting pancake winding
Authors: Gao Peifeng , Pan Yingzheng
Published: April 2022

Rare-earth barium copper oxide (REBCO) coated conductor (CC) tapes are promising for high-energy and high-field applications. In epoxy-impregnated REBCO superconducting windings, during the cooling process, the delamination induced by thermal mismatch stress significantly threatens stable operation due to the weak c-axial strength of REBCO CC tapes. In this study, a two-dimensional axisymmetric multilayer delamination finite element model with main layers of REBCO CC tapes and insulation materials was developed based on the bilinear cohesive zone model. Based on the proposed model, the stress distribution and delamination properties of an epoxy-impregnated REBCO winding induced during the cooling process were investigated. Furthermore, the effects on the structural configuration on the delamination and optimisation schemes of fabrication are discussed. The model results indicate that during the cooling process of the REBCO winding, when the radial tensile stress induced by the thermal mismatch stress is greater than the delamination strength, interface cracking will occur. Interface failure occurs in regions containing several turns of coils and not just a single-turn coil. Our analyses indicate that structural failure caused by delamination depends on the radius ratio of the outer to the inner winding, where a small radius ratio is preferred to reduce the risk of delamination. An excessive radius ratio can result in multiple delamination failures during the cooling process. The optimisation scheme, which divides the winding into several sub-windings with a consistently small radius ratio, is an effective method for mitigating the risk of delamination failure, which is consistent with available experimental results. Additionally, by reducing the thermal expansion coefficient of the epoxy resin, the risk of delamination failure during cooling can be significantly reduced. For the winding structure considered in this study, if the coefficient of thermal expansion of the epoxy resin is reduced to 5 (

×

10
6

K−1), then delamination failure caused by thermal mismatch will be eliminated. Our model results are consistent with those of several valuable experimental phenomena and numerical calculated in the literature.
Geometric quantum speed limits for Markovian dynamics in open quantum systems
Authors: Lan Kang , Xie Shijie , Cai Xiangji
Published: April 2022

We study theoretically the geometric quantum speed limits (QSLs) of open quantum systems under Markovian dynamical evolution. Three types of QSL time bounds are introduced based on the geometric inequality associated with the dynamical evolution from an initial state to a final state. By illustrating three types of QSL bounds at the cases of presence or absence of system driving, we demonstrate that the unitary part, dominated by system Hamiltonian, supplies the internal motivation for a Markovian evolution which deviates from its geodesic. Specifically, in the case of unsaturated QSL bounds, the parameters of the system Hamiltonian serve as the eigen-frequency of the oscillations of geodesic distance in the time domain and, on the other hand, drive a further evolution of an open quantum system in a given time period due to its significant contribution in dynamical speedup. We present physical pictures of both saturated and unsaturated QSLs of Markovian dynamics by means of the dynamical evolution trajectories in the Bloch sphere which demonstrates the significant role of system Hamiltonian even in the case of initial mixed states. It is further indicated that whether the QSL bound is saturated is ruled by the commutator between the Hamiltonian and reduced density matrix of the quantum system. Our study provides a detailed description of QSL times and reveals the effects of system Hamiltonian on the unsaturation of QSL bounds under Markovian evolution.
Analytical study on magnetic component of geodesic acoustic mode
Authors: Xie Baoyi , Ye Lei , Chen Yang , Zhao Pengfei , Guo Wenfeng , Xiang Nong
Published: April 2022

To understand the role of geodesic acoustic modes (GAMs) in regulating the transport by interacting with background electromagnetic turbulence, a thorough theoretical understanding of the magnetic components of the mode is required. In this study, the magnetic components of GAM are analytically investigated under the gyrokinetic framework with both the

m
=
1

and

m
=
2

harmonics are considered, where

m

is the poloidal mode number. With the quasi-neutrality condition and Ampère’s law, the amplitudes of various poloidal magnetic components are derived. It is shown that both

m
=
1

and

m
=
2

magnetic components exist and are dominated by the cosine and sine components, respectively. In addition, it is found that the amplitudes of all magnetic components increase with respect to the ratio of plasma pressure to magnetic pressure

β

and safety factor

q
.

Most importantly, the amplitude of

m
=
1

magnetic component is significantly enhanced due to the coupling of magnetic drift frequency with the first and second harmonics of the distribution functions, thus it can be comparable to that of

m
=
2

magnetic component under certain conditions. The various magnetic components derived in this study may provide some guidance for experimental measurements.
Synthesis and characterization of nanoparticles of semiconducting metal suplhide and their application
Authors: Darekar Madhavi Sharad , Praveen B M
Published: April 2022

Cadmium Sulphide (CdS) [II-VI group n-type semiconductor] and Copper Sulphide (Cu2S) [I-VI group p-type semiconductor] have large commercial applications like solar cell, gas sensor etc. Wide band gap CdS semiconductor was used as the transparent window material together with narrow band gap Cu2S semiconductor used as the absorber layer. Thioglycerol capped CdS and Cu2S nanoparticles were synthesized by using the non-aqueous chemical method at room temperature. CdS and Cu2S films were prepared on fluorine doped tin oxide (FTO) glass substrates by using the simple dip coating method at different dip times and heat treated in air. CdS and Cu2S nanoparticles were analysed by Ultraviolet-Visible absorption spectroscopy, photoluminescence (PL) and transmission electron microscopy (TEM). CdS and Cu2S films were investigated by scanning electron microscopy (SEM), energy dispersive analysis by x-rays (EDAX), mapping and atomic force microscopy (AFM). Thicknesses of films were determined using laser profilometer. Previously, preparation of solar cells using CdS and Cu2S films deposited by dip coating method has not been reported. In this study, thin-film solar cells with p-n heterojunction having enhanced conductivity, excellent solar energy conversion efficiency, enhanced fill factor, low cost and easy fabrication were prepared to increase the quality of solar cells.
Improving constraints on the reionization parameters using 21-cm bispectrum
Authors: Tiwari Himanshu , Shaw Abinash Kumar , Majumdar Suman , Kamran Mohd , Choudhury Madhurima
Published: April 2022

Radio interferometric experiments aim to constrain the reionization model parameters by measuring the 21-cm signal statistics, primarily the power spectrum. However the Epoch of Reionization (EoR) 21-cm signal is highly non-Gaussian, and this non-Gaussianity encodes important information about this era. The bispectrum is the lowest order statistic able to capture this inherent non-Gaussianity. Here we are the first to demonstrate that bispectra for large and intermediate length scales and for all unique k-triangle shapes provide tighter constraints on the EoR parameters compared to the power spectrum or the bispectra for a limited number of shapes of k-triangles. We use the Bayesian inference technique to constrain EoR parameters. We have also developed an Artificial Neural Network (ANN) based emulator for the EoR 21-cm power spectrum and bispectrum which we use to remarkably speed up our parameter inference pipeline. Here we have considered the sample variance and the system noise uncertainties corresponding to 1000 hrs of SKA-Low observations for estimating errors in the signal statistics. We find that using all unique k-triangle bispectra improves the constraints on parameters by a factor of 2 – 4 (depending on the stage of reionization) over the constraints that are obtained using power spectrum alone.
Breaking baryon-cosmology degeneracy with the electron density power spectrum
Authors: Nicola Andrina , Villaescusa-Navarro Francisco , Spergel David N. , Dunkley Jo , Anglés-Alcázar Daniel , Davé Romeel , Genel Shy , Hernquist Lars , Nagai Daisuke , Somerville Rachel S. , Wandelt Benjamin D.
Published: April 2022

Uncertain feedback processes in galaxies affect the distribution of matter, currently limiting the power of weak lensing surveys.
If we can identify cosmological statistics that are robust against these uncertainties, or constrain these effects by other means, then we can enhance the power of current and upcoming observations from weak lensing surveys such as DES, Euclid, the Rubin Observatory, and the Roman Space Telescope. In this work, we investigate the potential of the electron density auto-power spectrum as a robust probe of cosmology and baryonic feedback. We use a suite of (magneto-)hydrodynamic simulations from the CAMELS project and perform an idealized analysis to forecast statistical uncertainties on a limited set of cosmological and physically-motivated astrophysical parameters. We find that the electron number density auto-correlation, measurable through either kinematic Sunyaev-Zel'dovich observations or through Fast Radio Burst dispersion measures, provides tight constraints on Ω
m
and the mean baryon fraction in intermediate-mass halos, f̅
bar. By obtaining an empirical measure for the associated systematic uncertainties, we find these constraints to be largely robust to differences in baryonic feedback models implemented in hydrodynamic simulations. We further discuss the main caveats associated with our analysis, and point out possible directions for future work.
Ru thickness-dependent interlayer coupling and ultrahigh FMR frequency in FeCoB/Ru/FeCoB sandwich trilayers
Authors: Wang Le , Jing Zhao-Xuan , Zhou Ao-Ran , Li Shan-Dong
Published: April 2022

The antiferromagnetic (AFM) interlayer coupling effective field in a ferromagnetic/non-magnetic/ferromagnetic (FM/NM/FM) sandwich structure, as a driving force, can dramatically enhance the ferromagnetic resonance (FMR) frequency. Changing the non-magnetic spacer thickness is an effective way to control the interlayer coupling type and intensity, as well as the FMR frequency. In this study, FeCoB/Ru/FeCoB sandwich trilayers with Ru thickness (t
Ru) ranging from 1 Å to 16 Å are prepared by a compositional gradient sputtering (CGS) method. It is revealed that a stress-induced anisotropy is present in the FeCoB films due to the B composition gradient in the samples. A t
Ru-dependent oscillation of interlayer coupling from FM to AFM with two periods is observed. An AFM coupling occurs in a range of 2 Å ≤ t
Ru ≤ 8 Å and over 16 Å, while an FM coupling is present in a range of t
Ru < 2 Å and 9 Å ≤ t
Ru ≤ 14.5 Å. It is interesting that an ultrahigh optical mode (OM) FMR frequency in excess of 20 GHz is obtained in the sample with t
Ru = 2.5 Å under an AFM coupling. The dynamic coupling mechanism in trilayers is simulated, and the corresponding coupling types at different values of t
Ru are verified by Layadi’s rigid model. This study provides a controllable way to prepare and investigate the ultrahigh FMR films.
First principles study of hafnium intercalation between graphene and Ir(111) substrate
Authors: Peng Hao , Jin Xin , Song Yang , Du Shixuan
Published: April 2022

The intercalation of heteroatoms between graphene and metal substrates is a promising method for integrating epitaxial graphene with functional materials. Various elements and their oxides have been successfully intercalated into graphene/metal interfaces to form graphene-based heterostructures, showing potential applications in electronic devices. Here we theoretically investigate the hafnium intercalation between graphene and Ir(111). It is found that the penetration barrier of Hf atom is significantly large due to its large atomic radius, which suggests that hafnium intercalation should be carried out with low deposition doses of Hf atoms and high annealing temperatures. Our results show the different intercalation behaviors of a large-size atom and provide guidance for the integration of graphene and hafnium oxide in device applications.
Robustness measurement of scale-free networks based on motif entropy
Authors: Yang Yun-Yun , Feng Biao , Zhang Liao , Xue Shu-Hong , Xie Xin-Lin , Wang Jian-Rong
Published: April 2022

As a classical complex network model, scale-free network is widely used and studied. And motifs, as a high-order subgraph structure, frequently appear in scale-free networks, and have a great influence on the structural integrity, functional integrity and dynamics of the networks. In order to overcome the shortcomings in the existing work on the robustness of complex networks, only nodes or edges are considered, while the defects of high-order structure in the network are ignored. From the perspective of network motif, we propose an entropy of node degree distribution based on motif to measure the robustness of scale-free networks under random attacks. The effectiveness and superiority of our method are verified and analyzed in the BA scale-free networks.
Realizing reliable XOR logic operation via logical chaotic resonance in a triple-well potential system
Authors: Yang Huamei , Yao Yuangen
Published: April 2022

There exists an optimal range of intensity of a chaotic force in which the behavior of a chaos-driven bistable system with two weak inputs can be consistently mapped to a specific logic output. This phenomenon is called logical chaotic resonance (LCR). However, realization of a reliable exclusive disjunction (XOR) through LCR has not been reported. Here, we explore the possibility of using chaos to enhance the reliability of XOR logic operation in a triple-well potential system via LCR. The success probability P of obtaining XOR logic operation can take the maximum value of 1 in an optimal window of intensity D of a chaotic force. Namely, success probability P displays characteristic bell-shaped behavior by altering the intensity of the chaotic driving force, indicating the occurrence of LCR. Further, the effects of periodic force on LCR have been investigated. For a subthreshold chaotic force, a periodic force with appropriate amplitude and frequency can help enhance the reliability of XOR logic operation. Thus, LCR can be effectively regulated by changing the amplitude and frequency of the periodic force.
Image Desaturation for SDO/AIA Using Mixed Convolution Network
Authors: Yu Xuexin , Xu Long , Ren Zhixiang , Zhao Dong , Sun Wenqing
Published: April 2022

The Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) provides full-disk solar images with high temporal cadence and spatial resolution over seven extreme ultraviolet (EUV) wave bands. However, as violent solar flares happen, images captured in EUV wave bands may have saturation in active regions, resulting in signal loss. In this paper, we propose a deep learning model to restore the lost signal in saturated regions by referring to both unsaturated/normal regions within a solar image and statistical probability model of massive normal solar images. The proposed model, namely mixed convolution network (MCNet), is established over conditional generative adversarial network (GAN) and the combination of partial convolution (PC) and validness migratable convolution (VMC). These two convolutions were originally proposed for image inpainting. In addition, they are implemented only on unsaturated/valid pixels, followed by certain compensation to compensate the deviation of PC/VMC relative to normal convolution. Experimental results demonstrate that the proposed MCNet achieves favorable desaturated results for solar images and outperforms the state-of-the-art methods both quantitatively and qualitatively.
Operation and performance of a dual-phase crystalline/vapor xenon time projection chamber
Authors: Kravitz S. , Chen H. , Gibbons R. , Haselschwardt S.J. , Xia Q. , Sorensen P.
Published: April 2022

We have built and operated a crystalline/vapor xenon TPC, with the goal of improving searches for dark matter. The motivation for this instrument is the fact that beta decays from the radon decay chain to the ground state presently limit the state-of-the-art liquid/vapor xenon experiments. In contrast, a crystalline xenon target has the potential to exclude, or tag and reject radon-chain backgrounds. As a preamble to demonstrating such capabilities, the present article makes a first demonstration of the operation of a crystalline/vapor xenon TPC with electroluminescence (gas gain) for the electron signal readout. It also shows that the scintillation yield in crystalline xenon appears to be identical to that in liquid xenon, in contrast to previous results.
The influence of land-use activities and regional drought on historical fire regimes of Buryatia, Siberia
Authors: Bigio Erica R , Swetnam Thomas W , Baisan Christopher H , Guiterman Christopher H , Kisilyakhov Yegor K , Andreev Sergey G , Batotsyrenov Eduard A , Ayurzhanaev Alexander A
Published: April 2022

Every year, millions of hectares burn across Siberia, driven by a combination of warming temperatures, regional drought and human-caused ignitions. Dendrochronology provides a long-term context to evaluate recent trends in fire activity and interpret the relative influence of humans and climate drivers on fire regimes. We developed a 400 year record of fire-scarred trees from 17 sites in pine-dominated forests located southeast of Lake Baikal. Site-level mean fire return intervals (MFIs) ranged from 4 to 27 years for all fires and 8 to 35 years for widespread fires within sites. Sites with the lowest MFI values were located within 1 km of agricultural fields in grassland valleys, suggesting that agricultural burning influenced MFIs at nearby sites. Fire frequency varied over the record, with significantly high values around 1790, from 1865 to 1880, 1948 to 1955 and 1995 to 2005. The increased fire activity corresponded with migration waves to the region and major socio-economic change connected with the establishment and breakdown of the Soviet Union. At broader scales, superposed epoch analysis showed that synchronous fire years were associated with regional drought and precipitation deficits. Wet conditions for 2–3 years prior to the event year were also significant, suggesting that increased moisture promoted growth of understory fine fuels to support more extensive fires across the study area. Although fire frequencies increased during the 20th century, fire–climate relationships weakened, suggesting increased human-caused ignitions may override regional climate drivers. Our dataset presents a continuous record of frequent surface fires over the past 400 years, providing a valuable opportunity to compare dendrochronology-based reconstructions with satellite and documentary records.
Time-series maps reveal widespread change in plant functional type cover across Arctic and boreal Alaska and Yukon
Authors: Macander Matthew J , Nelson Peter R , Nawrocki Timm W , Frost Gerald V , Orndahl Kathleen M , Palm Eric C , Wells Aaron F , Goetz Scott J
Published: April 2022

Widespread changes in the distribution and abundance of plant functional types (PFTs) are occurring in Arctic and boreal ecosystems due to the intensification of disturbances, such as fire, and climate-driven vegetation dynamics, such as tundra shrub expansion. To understand how these changes affect boreal and tundra ecosystems, we need to first quantify change for multiple PFTs across recent years. While landscape patches are generally composed of a mixture of PFTs, most previous moderate resolution (30 m) remote sensing analyses have mapped vegetation distribution and change within land cover categories that are based on the dominant PFT; or else the continuous distribution of one or a few PFTs, but for a single point in time. Here we map a 35 year time-series (1985–2020) of top cover (TC) for seven PFTs across a 1.77 × 106 km2 study area in northern and central Alaska and northwestern Canada. We improve on previous methods of detecting vegetation change by modeling TC, a continuous measure of plant abundance. The PFTs collectively include all vascular plants within the study area as well as light macrolichens, a nonvascular class of high importance to caribou management. We identified net increases in deciduous shrubs (66 × 103 km2), evergreen shrubs (20 × 103 km2), broadleaf trees (17 × 103 km2), and conifer trees (16 × 103 km2), and net decreases in graminoids (−40 × 103 km2) and light macrolichens (−13 × 103 km2) over the full map area, with similar patterns across Arctic, oroarctic, and boreal bioclimatic zones. Model performance was assessed using spatially blocked, nested five-fold cross-validation with overall root mean square errors ranging from 8.3% to 19.0%. Most net change occurred as succession or plant expansion within areas undisturbed by recent fire, though PFT TC change also clearly resulted from fire disturbance. These maps have important applications for assessment of surface energy budgets, permafrost changes, nutrient cycling, and wildlife management and movement analysis.
Coupled insights from the palaeoenvironmental, historical and archaeological archives to support social-ecological resilience and the sustainable development goals
Authors: Allen K J , Reide F , Gouramanis C , Keenan B , Stoffel M , Hu A , Ionita M
Published: April 2022

Many governments and organisations are currently aligning many aspects of their policies and practices to the sustainable development goals (SDGs). Achieving the SDGs should increase social-ecological resilience to shocks like climate change and its impacts. Here, we consider the relationship amongst the three elements—the SDGs, social-ecological resilience and climate change—as a positive feedback loop. We argue that long-term memory encoded in historical, archaeological and related ‘palaeo-data’ is central to understanding each of these elements of the feedback loop, especially when long-term fluctuations are inherent in social-ecological systems and their responses to abrupt change. Yet, there is scant reference to the valuable contribution that can be made by these data from the past in the SDGs or their targets and indicators. The historical and archaeological records emphasise the importance of some key themes running through the SDGs including how diversity, inclusion, learning and innovation can reduce vulnerability to abrupt change, and the role of connectivity. Using paleo-data, we demonstrate how changes in the extent of water-related ecosystems as measured by indicator 6.6.1 may simply be related to natural hydroclimate variability, rather than reflecting actual progress towards Target 6.6. This highlights issues associated with using SDG indicator baselines predicated on short-term and very recent data only. Within the context of the contributions from long-term data to inform the positive feedback loop, we ask whether our current inability to substantively combat anthropogenic climate change threatens achieving both the SDGS and enhanced resilience to climate change itself. We argue that long-term records are central to understanding how and what will improve resilience and enhance our ability to both mitigate and adapt to climate change. However, for uptake of these data to occur, improved understanding of their quality and potential by policymakers and managers is required.
Tuning quantum–classical correspondence for atomic and molecular systems in a cavity
Authors: Moiseyev Nimrod , Šindelka Milan
Published: April 2022

We show that the correspondence between quantum and classical mechanics can be tuned by varying the coupling strength between an atom or a molecule and the modes of a cavity. In the acceleration gauge (AG) representation, the cavity–matter system is described by an effective Hamiltonian, with a non-trivial coupling appearing in the potential, and with renormalized masses. Importantly, and counterintuitively, the AG coupling changes non-monotonically with the strength of the cavity–matter interaction. As a result, one obtains an effective (approximately decoupled) cavity–matter dynamics both for the case of weak and strong interactions. In the weak coupling regime, the effective mass parameters essentially coincide with their standard interaction free counterparts. In contrast, the renormalized atomic/molecular mass increases as the cavity–matter interaction is increased. This results in AG dynamics of matter governed by a conventionally looking atomic/molecular Hamiltonian, whose effective Planck constant is reduced when the cavity–matter interaction is increased.
Localization of space-inhomogeneous three-state quantum walks
Authors: Kiumi Chusei
Published: April 2022

Mathematical analysis on the existence of eigenvalues is essential because it is deeply related to localization, which is an exceptionally crucial property of quantum walks (QWs). We construct the method for the eigenvalue problem via the transfer matrix for space-inhomogeneous three-state QWs in one dimension with a self-loop, which is an extension of the technique in a previous study (Kiumi and Saito 2021 Quantum Inf. Process.
20 171). This method reveals the necessary and sufficient condition for the eigenvalue problem of a two-phase three-state QW with one defect whose time evolution varies in the negative part, positive part, and at the origin.
Exhaled VOCs can discriminate subjects with COVID-19 from healthy controls
Authors: Woollam Mark , Angarita-Rivera Paula , Siegel Amanda P , Kalra Vikas , Kapoor Rajat , Agarwal Mangilal
Published: April 2022

COVID-19 detection currently relies on testing by reverse transcription polymerase chain reaction (RT-PCR) or antigen testing. However, SARS-CoV-2 is expected to cause significant metabolic changes in infected subjects due to both metabolic requirements for rapid viral replication and host immune responses. Analysis of volatile organic compounds (VOCs) from human breath can detect these metabolic changes and is therefore an alternative to RT-PCR or antigen assays. To identify VOC biomarkers of COVID-19, exhaled breath samples were collected from two sample groups into Tedlar bags: negative COVID-19 (n = 12) and positive COVID-19 symptomatic (n = 14). Next, VOCs were analyzed by headspace solid phase microextraction coupled to gas chromatography-mass spectrometry. Subjects with COVID-19 displayed a larger number of VOCs as well as overall higher total concentration of VOCs (p < 0.05). Univariate analyses of qualified endogenous VOCs showed approximately 18% of the VOCs were significantly differentially expressed between the two classes (p < 0.05), with most VOCs upregulated. Machine learning multivariate classification algorithms distinguished COVID-19 subjects with over 95% accuracy. The COVID-19 positive subjects could be differentiated into two distinct subgroups by machine learning classification, but these did not correspond with significant differences in number of symptoms. Next, samples were collected from subjects who had previously donated breath bags while experiencing COVID-19, and subsequently recovered (COVID Recovered subjects (n = 11)). Univariate and multivariate results showed >90% accuracy at identifying these new samples as Control (COVID-19 negative), thereby validating the classification model and demonstrating VOCs dysregulated by COVID are restored to baseline levels upon recovery.
The significance of ophiomorpha trace fossils as key sedimentological parameters for paleoenvironment assessment – case example in Klias and Kudat Peninsulas, Sabah
Authors: Shamsuddin A.A.S , Jirin S. , Razak M.S.F.A. , Kadir M.F.A. , Harith Z.Z.T. , Ghani A.F.A. , Mubin M.
Published: April 2022

Trace fossils amongst other sedimentological features are one of the key sedimentological parameters commonly used to assess paleoenvironment. This paper discusses on the occurrence of trace fossil of ichnogenera Ophiomorpha observed in outcrops of Temburong and Belait formations around Klias and Kudat peninsulas. The burrows which are commonly observed at the outcrop sites belong to four ichnospecies: O. rudis, O. annulata, O. recta and O. nodosa. They are variably oriented from vertical to sub-vertical and horizontal, branched to unbranched. In Temburong Formation, O. rudis, O. annulata, O. recta ichnospecies were observed quite commonly which are associated with deep marine environment. Meanwhile, Ophiomorpha nodosa that typically related with shallow-marine trace fossils only observed in Belait Formations. Based on the trace fossil occurrence in conjunction with other sedimentological observations, the paleoenvironment assessment was further improved.
Improving accuracy and efficiency in elastic finite difference modelling
Authors: Ang Chin Tee , Ghosh Deva Prasad
Published: April 2022

Multicomponent technology has known to have a better imaging quality as compared to P-wave imaging. However, the cost of acquiring and processing the multicomponent data is more costly than P-wave imaging. Although P-wave imaging may have poorer imaging capability as compared to shear wave imaging, a good P-wave imaging can still be obtained if a good seismic modelling technique is used. Thus, this paper aims to enhance seismic modelling technique, in terms of accuracy, suppression of grid dispersion, and reduction in computation time. The finite difference (FD) technique is used as the modelling scheme, and the elastic modelling approach is used in this paper. The new method is applied on homogeneous model and synthetic data, and then compared to conventional FD modelling (4th order), higher order FD modelling (14th order), optimization of staggered grid coefficients such as least squares method and Wang & Liang’s method. The comparison will then be shown and discussed.
The effect of particle size towards resistivity and chargeability for groundwater interpretation
Authors: Malik Ahmad Khairul Abd , Madun Aziman , Dan Mohd Firdaus Md , Tajudin Saiful Azhar Ahmad , Talib Mohd Khaidir Abu , Azmi Mohammad Izzat Shaffiq , Noh Khairul Arifin Mohd , Joret Ariffuddin
Published: April 2022

The most reliable and common method of surveying the groundwater is the electrical resistivity tomography (ERT). ERT is a non-destructive method of groundwater surveying where the current is being injected into the ground and the value of the subsurface resistivity and chargeability are determined. Multiple factors may influence the results of the ERT, especially the mineralogy, soils, rocks and water content. In this study, the effects of particle size and moisture content are assessed towards the resistivity and chargeability value. The materials that are used to conduct the testing are obtained from quarry and river. The gravel size samples from quarry were varied from sample size retained at 37.5 mm, 28mm, 20mm, 11.2mm, 6.7mm, 5mm and 2.36mm. Meanwhile, the sand size samples from the river were varied from sample sieve size passing 2mm and retained at 1.18 mm, 0.85mm, 0.60mm, 0.43mm, 0.30mm, 0.20mm, 0.15mm and 0.063 mm sieve. The gravel and sand-sized particles were tested on a saturated condition. The device used for the experiment is Terrameter LS 2 and the setting used is C1C2P1P2 to conduct the resistivity and induced polarization tests. The resistivity value for the gravel ranges from 162.5 Ωm at its highest to 77.5 Ωm at its lowest. In a fully saturated condition, the resistivity value for the sand ranges from 121 Ωm at its highest to 86.1 Ωm at its lowest. The chargeability value for the gravel in a saturated condition ranges from 5.57 ms to 7.87 ms with decreasing particle size. The highest chargeability value for sand is 12.31 ms and the lowest is 2.04 ms in a fully saturated condition also in a decreasing size of particle size. The resistivity and chargeability for water used in this study are 101.7 Ωm and 0.41 ms, respectively. Keywords: Resistivity, Induced Polarization, Granite, Sand, Chargeability.
Geochemistry analysis of geothermal water in Tulabolo Timur, Sulawesi, Indonesia
Authors: Napu Siti Suhartini S. , Manyoe Intan Noviantari , Arifin Yayu Indriati
Published: April 2022

Gorontalo has several geothermal manifestations, such as Lombongo, Pangi, Libungo, Hungayono and Tulabolo Timur. Research on geothermal areas must be carried out to obtain surface and subsurface information, then the geothermal areas can be further developed. The purpose of this study was to analyse the geochemistry water of the geothermal water in Tulabolo Timur, Bone Bolango Regency, Gorontalo Province, Sulawesi, Indonesia. The research method is divided into field observations and laboratory analysis. Data processing using Atomic Absorption Spectrophotometer (AAS) for cation and anion test. Data processing using Picaro Water Isotope Analyzer for isotope test. Subsurface temperature is determined using the geothermometer Na-K Giggenbach formula. The results of this research show that the fluid type of Tulabolo Timur geothermal area is chloride and the origin of fluid is from deep reservoir. Geothermal fluid when it approaches the surface is not affected by surrounding rocks. Tulabolo Timur geothermal fluids are categorized in the upflow zone. Geothermal fluid when it reaches the surface is diluted with meteoric water. Meteoric water is infiltrated below the surface in the recharge area, which is located in the north and south of the study area. The subsurface temperature of Tulabolo Timur is included in the high-temperature system.
Tunable plasmon-induced transparency in graphene-based plasmonic waveguide for terahertz band-stop filters
Authors: Li Meiping , Shi Yanpeng , Liu Xiaoyu , Song Jinmei , Wang Xiaodong , Yang Fuhua
Published: April 2022

Terahertz (THz) tunable filters have great advantages in miniaturizing integrated and multiband communication systems. Here, THz band-stop filter with switchable single/double plasmon-induced transparency (PIT) based on metal-dielectric-metal waveguide consisting of a ring-stub cavity and two graphene ribbons (GRs) on stub sidewalls is proposed. The switchable characteristics of single and dual-PIT are investigated numerically and theoretically by the finite-difference time-domain and the radiating multi-oscillator theory, displaying good correspondence. The single-PIT is excited by the destructive interference between bright mode and dark mode, which possesses significant tunability of resonant frequency and transmission amplitude due to the existence of GRs. When independently regulating chemical potentials of GRs on the left and right sidewalls, the dual-PIT emerges. And the filter based on dual-PIT switches from single stopband to dual-stopband or even multi-stopband filtering. Besides, the band-stop filtering performance of the tunable PIT can be further optimized by increasing the number of ring-stub cavities. The tunable PIT in graphene-based plasmonic waveguide holds potential for THz multiband communications and subwavelength plasmonic devices, such as filters, switches, modulators.
Orbital angular momentum sidebands in second harmonic generation of a vortex beam by a nonlinear crystal with inhomogeneous refractive index
Authors: Ghavami Sabouri Saeed
Published: April 2022

The manipulation of the orbital angular momentum (OAM) spectrum in new wavelengths generated by frequency conversion has a wide range of applications in quantum information technology and modern communications. Here, the second harmonic generation of a vortex beam in a nonlinear crystal with an inhomogeneous refractive index is considered. It is shown that by using a segmented oven and generating a controllable temperature gradient along the thickness of the nonlinear crystal, a transverse phase mismatch can be induced in the vortex beam. Accordingly, the OAM spectrum of the vortex beam can be changed by generating new OAM components in the spectrum. Compared with the nonlinear Bragg diffraction method, the presented method has the advantage of longer interaction length and higher efficiency.
On the Legibility of Immigration Today
Authors: Huehls Mitchum
Published: April 2022

Claudia Sadowski-Smith’s The New Immigrant Whiteness: Race, Neoliberalism, and Post-Soviet Migration to the United States (2018) and Alexandra Perisic’s Precarious Crossings: Immigration, Neoliberalism, and the Atlantic (2019) present unique challenges to contemporary immigration discourse. Focusing on post-Soviet immigrants to the US, Sadowski-Smith explores the complicated role that whiteness plays for immigrants who look white but suffer similar economic precarity and material deprivation as non-white immigrants. Sadowski-Smith’s work complicates our understanding of white privilege and makes the specific precarities of the post-Soviet immigrant newly legible. The immigrants in Perisic’s study aren’t white, but she provocatively suggests that their racial, ethnic, and national specificity should not be the primary lens for understanding their immigrant experience. Instead, challenging the tendency to read contemporary immigration through the racialized, postcolonial logic of the Black Atlantic, Perisic emphasizes global neoliberalism and economic precarity as defining features of contemporary immigrant experience. Whereas Sadowski-Smith seeks to make post-Soviet immigrants legible to contemporary immigration discourse, Perisic observes the many ways that immigrants today strategically lean into and embrace precarity, effectively making themselves illegible and inassimilable to liberal values. Taken together, these two monographs advance our thinking about immigration in challenging and provocative ways.
The Influence of Processing Speed, Attention, and Inhibition on Texas Functional Living Scale Performance
Authors: Roye Scott , Linck John F , Hoffmeister Jordan , Copeland Christopher T
Published: April 2022

Objective

Attention, inhibition, and processing speed are related to functional decline among older adults. This study attempts to clarify the relationships between these cognitive factors and adaptive functioning.

Method

We examined relationships between attention, inhibition, and processing speed, with scores on the Texas Functional Living Scale (TFLS), a performance-based measure of daily functioning, in a mixed clinical sample of 530 older adults who were referred for an outpatient neuropsychological evaluation.

Results

The current study used a confirmatory factor analysis (CFA) to derive a three-factor cognitive model consisting of attention, inhibition, and processing speed. Results from a hierarchical regression, which included factor scores from the CFA, revealed that processing speed was the only significant predictor of TFLS performance when all three cognitive factors were included within a single model.

Conclusion

These results highlight the influence of processing speed as an important indicator of functional decline among a clinical population of older adults.
Simulation and annotation of global acronyms
Authors: Filimonov Maxim , Chopard Daphné , Spasić Irena
Published: April 2022

Motivation

Global acronyms are used in written text without their formal definitions. This makes it difficult to automatically interpret their sense as acronyms tend to be ambiguous. Supervised machine learning approaches to sense disambiguation require large training datasets. In clinical applications, large datasets are difficult to obtain due to patient privacy. Manual data annotation creates an additional bottleneck.

Results

We proposed an approach to automatically modifying scientific abstracts to (i) simulate global acronym usage and (ii) annotate their senses without the need for external sources or manual intervention. We implemented it as a web-based application, which can create large datasets that in turn can be used to train supervised approaches to word sense disambiguation of biomedical acronyms.

Availability and implementation

The datasets will be generated on demand based on a user query and will be downloadable from https://datainnovation.cardiff.ac.uk/acronyms/.
Targeting cyclin-dependent kinase 7—association between CDK7 and pMED1 expression in prostate cancer tissue
Authors: Paulsen Finn-Ole , Kang Duan , Becker Finn , Roth Doris , Joerg Vincent , Dreyer Eva , Roesch Marie C , Seidel Christoph , Merseburger Axel S , Kirfel Jutta , Sailer Verena , Offermann Anne , Perner Sven
Published: April 2022

Cyclin-dependent kinase (CDK) 7-mediated phosphorylation of Mediator-complex subunit 1 (MED1) enhances androgen receptor (AR) activity in prostate cancer (PCa). Hyperactive AR-signalling plays a key role for the development of castration resistance. Several CDK7 inhibitors are currently under investigation in Phase I/II trials addressing solid tumours, including PCa. Aim of this study was to characterize the CDK7/phospho-(p)MED1 axis in human tissue. Immunohistochemistry was performed on 595 PCa samples including 394 primary tumour foci obtained by radical prostatectomy (RP), 64 advanced or recurrent tumours obtained by palliative transurethral resection of the prostate (pTUR), 65 lymph node metastases (LNM), 35 distant metastases (DM) and 36 benign samples. CDK7 is expressed in 79.3% of PCa tissues and protein levels are significantly higher in LNM, pTUR and DM and lower in benign tissues compared to primary tumours. CDK7 and pMED1 expression show strong positive correlation. High expression of CDK7 associated with shorter 5-year biochemical recurrence-free-survival (63.0% vs. 85.0%) and reduced survival persists when adjusted for T-Stage, nodal status, resection boundaries, grade group and pre-operative prostate-specific antigen in multivariate Cox-regression (hazard ratio 4.30; 95% CI, 1.43 to 12,40, P = 0.007). High CDK7 and pMED1 levels correlate with nuclear AR expression. CDK7 positive tumours harbour higher Ki67 expression indices and show more frequently positive ERG (ETS-related gene)-status. In conclusion, CDK7 is frequently expressed in human PCa and predicts disease recurrence after RP. Therapeutical inhibition of CDK7 might be a promising approach in treatment of advanced PCa.
Attentional modulation of beta-power aligns with the timing of behaviorally relevant rhythmic sounds
Authors: Foldal Maja D , Leske Sabine , Blenkmann Alejandro O , Endestad Tor , Solbakk Anne-Kristin
Published: April 2022

It is largely unknown how attention adapts to the timing of acoustic stimuli. To address this, we investigated how hemispheric lateralization of alpha (7–13 Hz) and beta (14–24 Hz) oscillations, reflecting voluntary allocation of auditory spatial attention, is influenced by tempo and predictability of sounds. We recorded electroencephalography while healthy adults listened to rhythmic sound streams with different tempos that were presented dichotically to separate ears, thus permitting manipulation of spatial–temporal attention. Participants responded to stimulus-onset-asynchrony (SOA) deviants (−90 ms) for given tones in the attended rhythm. Rhythm predictability was controlled via the probability of SOA deviants per block. First, the results revealed hemispheric lateralization of beta-power according to attention direction, reflected as ipsilateral enhancement and contralateral suppression, which was amplified in high- relative to low-predictability conditions. Second, fluctuations in the time-resolved beta-lateralization aligned more strongly with the attended than the unattended tempo. Finally, a trend-level association was found between the degree of beta-lateralization and improved ability to distinguish between SOA-deviants in the attended versus unattended ear. Differently from previous studies, we presented continuous rhythms in which task-relevant and irrelevant stimuli had different tempo, thereby demonstrating that temporal alignment of beta-lateralization with attended sounds reflects top-down attention to sound timing.
Coronavirus Disease 2019 Vaccine Boosting in Previously Infected or Vaccinated Individuals
Authors: Shrestha Nabin K , Shrestha Priyanka , Burke Patrick C , Nowacki Amy S , Terpeluk Paul , Gordon Steven M
Published: April 2022

Background

The purpose of this study was to determine whether boosting previously infected or vaccinated individuals with a vaccine developed for an earlier variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) protects against the Omicron variant.

Methods

Employees of Cleveland Clinic, previously infected with or vaccinated against coronavirus disease 2019 (COVID-19) and working the day the Omicron variant was declared a variant of concern, were included. The cumulative incidence of COVID-19 was examined over 2 months during an Omicron variant surge. Protection provided by boosting was evaluated using Cox proportional hazards regression. Analyses were adjusted for time since proximate SARS-CoV-2 exposure.

Results

Among 39 766 employees, 8037 (20%) previously infected and the remaining previously vaccinated, COVID-19 occurred in 6230 (16%) during the study. Risk of COVID-19 increased with time since proximate SARS-CoV-2 exposure, and boosting protected those >6 months since prior infection or vaccination. In multivariable analysis, boosting was independently associated with lower risk of COVID-19 among those vaccinated but not previously infected (hazard ratio [HR], .43; 95% confidence interval [CI], .41–.46) as well as those previously infected (HR, .66; 95% CI, .58–.76). Among those previously infected, receipt of 2 compared with 1 dose of vaccine was associated with higher risk of COVID-19 (HR, 1.54; 95% CI, 1.21–1.97).

Conclusions

Administering a COVID-19 vaccine not designed for the Omicron variant >6 months after prior infection or vaccination protects against Omicron variant infection. There is no advantage to administering more than 1 dose of vaccine to previously infected persons.
Media and Communication Studies. What is there to Decolonize?
Authors: Magallanes-Blanco Claudia
Published: April 2022

Following a decolonial perspective, I argue that there is a coloniality of representations that shapes our understanding of the world and our place in it and that perpetuates an ongoing system of domination and inequality that we have incorporated as a natural order.
Decolonizing Digital Methods
Authors: Bosch Tanja
Published: April 2022

The rapid growth of the Internet and social media platforms has increasingly made these central focus areas for media scholars around the world. Within the context of the broader framework of the movement towards decolonizing media and communication studies, this growth of digital methods raises key questions including: How are digital methods in these contexts currently being used and how might scholars begin to think about “decolonizing” these methods? What do digital methods look like in a context of the digital divide? This short commentary reflects on these questions to make an argument for the need to decolonize digital methods.