bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liver tumor detection based on objects as points
Authors: Peng Xuefeng , Yang Xinwu 
Published: November 2021

Abstract
The automatic detection of liver tumors by computed tomography is challenging, owing to their wide variations in size and location, as well as to their irregular shapes. Existing detection methods largely rely on two-stage detectors and use CT images marked with bounding boxes for training and detection. In this study, we propose a single-stage detector method designed to accurately detect multiple tumors simultaneously, and provide results demonstrating its increased speed and efficiency compared to prior methods. The proposed model divides CT images into multiple channels to obtain continuity information and implements a bounding box attention mechanism to overcome the limitation of inaccurate prediction of tumor center points and decrease redundant bounding boxes. The model integrates information from various channels using an effective Squeeze-and-Excitation attention module. The proposed model obtained a mean average precision result of 0.476 on the Decathlon dataset, which was superior to that of the prior methods examined for comparison. This research is expected to enable physicians to diagnose tumors very efficiently; particularly, the prediction of tumor center points is expected to enable physicians to rapidly verify their diagnostic judgments. The proposed method is considered suitable for future adoption in clinical practice in hospitals and resource-poor areas because its superior performance does not increase computational cost; hence, the equipment required is relatively inexpensive.
Effect of tailored density profiles on the stability of imploding Z-pinches at microsecond rise time megaampere currents
Authors: Cherdizov R K , Baksht R B , Kokshenev V A , Oreshkin V I , Rousskikh A G , Shishlov A V , Shmelev D L , Zhigalin A S 
Published: November 2021

Abstract
To study the effect of the radial density profile of the material of a metal-plasma Z-pinch load on the development of magneto-Rayleigh–Taylor (MRT) instabilities, experiments have been performed at the Institute of High Current Electronics with the GIT-12 generator which produces microsecond rise time megaampere currents. The Z-pinch load was an aluminum plasma jet (PJ) with an outer plasma shell. This configuration leads to the formation of a uniform current sheath in a Z-pinch load upon application of a high-voltage pulse. It was successfully used in experiments with hybrid deuterium gas-puffs (Klir et al 2020 New J. Phys.
22 103036). The initial density profiles of the Z-pinch loads were estimated from the pinch current and voltage waveforms using the zero-dimensional ‘snowplow’ model, and they were verified by simulating the expansion of the PJ formed by a vacuum arc using a two-dimensional quasi-neutral hybrid model (Shmelev et al 2020 Phys. Plasmas
27 092708). Two Z-pinch load configurations were used in the experiments. The first configuration provided tailored load density profiles, which could be described as ρ(r) ≈ 1/r^s for s > 2. In this case, MRT instabilities were suppressed and thus a K-shell radiation yield of 11 kJ cm−1 and a peak power of 0.67 TW cm−1 could be attained at a current of about 3 MA. For the second configuration, the radial density profiles were intentionally changed using a reflector. This led to the appearance of a notch in the density profiles at radii of 1–3 cm from the pinch axis and to magnetohydrodynamic instabilities at the final implosion stage. As a result, the K-shell radiation yield more than halved and the power decreased to 0.15 TW cm−1 at a current of about 3.5 MA.
Soliton generation and drift wave turbulence spreading via geodesic acoustic mode excitation
Authors: Chen Ningfei , Wei Shizhao , Wei Guangyu , Qiu Zhiyong 
Published: November 2021

Abstract
The two-field equations that govern fully nonlinear dynamics of the drift wave (DW) and geodesic acoustic mode (GAM) interaction in toroidal geometry are derived within the nonlinear gyrokinetic framework. Two stages with distinctive features are identified and analyzed using both analytical and numerical approaches. In the ‘linear’ growth stage, the derived set of nonlinear equations can be reduced to the intensively studied parametric decay instability, accounting for the spontaneous resonant excitation of GAM by the DW. The main results of previous works on spontaneous GAM excitation, e.g. the greatly enhanced GAM group velocity and the nonlinear growth rate of GAM, are reproduced from the numerical solution of the two-field equations. In the fully nonlinear stage, soliton structures are observed to form due to the balancing of the self-trapping effect by the spontaneously excited GAM and kinetic dispersiveness of the DW. The soliton structures enhance turbulence spreading from the DW linearly unstable region to the stable region, exhibiting convective propagation instead of a typical linear dispersive process, and are thus expected to induce core-edge interaction and nonlocal transport.
Modeling of high power impulse magnetron sputtering discharges with graphite target
Authors: Eliasson H , Rudolph M , Brenning N , Hajihoseini H , Zanáška M , Adriaans M J , Raadu M A , Minea T M , Gudmundsson J T , Lundin D 
Published: November 2021

Abstract
The ionization region model (IRM) is applied to model a high power impulse magnetron sputtering discharge in argon with a graphite target. Using the IRM, the temporal variation of the various species and the average electron energy, as well as internal parameters such as the ionization probability, back-attraction probability, and the ionized flux fraction of the sputtered species, is determined. It is found that thedischarge develops into working gas recycling and most of the discharge current at the cathode target surface is composed of Ar+ ions, which constitute over 90% of the discharge current, while the contribution of the C+ ions is always small (

<
5

%), even for peak current densities close to 3 A cm−2. For the target species, the time-averaged ionization probability ⟨α
t,pulse⟩ is low, or 13–27%, the ion back-attraction probability during the pulse β
t,pulse is high (

>
92

%), and the ionized flux fraction is about 2%. It is concluded that in the operation range studied here it is a challenge to ionize carbon atoms, that are sputtered off of a graphite target in a magnetron sputtering discharge, when depositing amorphous carbon films.
A study of mechanoelectrical transduction behavior in polyvinyl chloride (PVC) gel as smart sensors
Authors: Neubauer Justin , Olsen Zakai J , Frank Zachary , Hwang Taeseon , Kim Kwang J 
Published: November 2021

Abstract
Polyvinyl chloride (PVC) gels are soft electroactive polymers (EAPs) being researched for soft robotic applications. Sensing properties of these EAPs have not been investigated in detail in regard to fundamental mechanoelectrical transduction behavior, but this smart material has been shown to exhibit a detectable response to external stimuli. This study shows PVC gels to be an extremely sensitive material when undergoing mechanoelectrical transduction and explores some response dependencies and proposes a theoretical framework for mechanoelectrical transduction within the gel. The work presented here also uncovers a very interesting phenomena under extremely low compressive loads during the initial contact with the gel. This phenomenon is attributed to a surface tension creeping motion onto the loading surface with an accompanying polarity inversion in the sensing signal relative to fully loaded gels in compression. Experimental work on hysteresis was also completed showing very little memory in steady state mechanoelectrical response to repeated stepped loading cycles. This study demonstrates the mechanoelectric ability of PVC gels to perform in sensing experiments and acts as a fundamental framework to further broaden the applications of PVC gel sensors.
Ab initio calculations of the elastic, vibrational, electronic properties, and electron-phonon constant of superconducting YB6 compound under low pressure
Authors: Romero M , Arévalo-López E P , Rosas-Huerta J L , Antonio J E , Benitez-Rico A , Marquina M L , Escamilla R 
Published: November 2021

Abstract
The crystal structure, mechanical, electronic properties, as well as the electron-phonon constant of YB6 under low pressure (<1.0 GPa) were investigated by first-principles density functional theory (DFT) within the bounds of the generalized gradient approximation (GGA). The calculated cell parameter a at zero pressure is in good agreement with the reported experimental and theoretically data and decreases as pressure increases. Under pressure, the elastic constants and mechanical moduli increase while the hardness decreases. The calculated elastic constants reveals mechanical stability up to 1 GPa. Pugh's criterion and Poisson's ratio suggest that the compound has ductile behavior. The electronic density of states (DOS) under pressure shows a slight decrease due to reducing the B 2p states. Finally, the electron-phonon coupling constant (λ

e−f
) was determined using the Debye temperature and the McMillan equation, the value found was λ

e−f
= 0.53 as a function of pressure; therefore, our results suggest that the YB6 is an intermediate coupling superconductor.
Gamma radiation shielding properties of recycled polyvinyl chloride composites reinforced with micro/nano-structured PbO and CuO particles
Authors: El-Khatib Ahmed M , Abbas Yehia M , Badawi Mohamed S , Hagag Osama M , Alabsy Mahmoud T 
Published: November 2021

Abstract
In this work, the γ-ray shielding characteristics of fabricated recycled polyvinyl chloride (rPVC) loaded with micro and nano fillers of PbO and CuO composites were investigated. The PbO/rPVC and CuO/rPVC composites were prepared by changing the percentage of injected materials (PbO and CuO) between 10% and 40% with additions by 10%. Gamma-ray attenuation properties, such as mass attenuation coefficients, linear attenuation coefficients and half-value layer for PbO and CuO-supported polymers were obtained in the energy range between 59.5 and 1408.0 keV using narrow beam transmission geometry. These experiments were carried out by using a HPGe detector and five standard radioactive sources [241Am, 133Ba, 137Cs, 60Co and 152Eu]. Moreover, equivalent atomic numbers and the exposure buildup factor (EBF) values for incident photon energy in the range from 0.015 MeV to 15 MeV were also calculated by Geometric Progression (G-P) method. The experimental results revealed that, the measured values of the linear attenuation coefficients of the PbO/rPVC and CuO/rPVC composites showed their dependence on the type and the concentration of the filler (either PbO or CuO) and also on the incident gamma ray energy. Increasing the filler weight fractions wt.% in the rPVC matrix, increases the linear attenuation coefficients of the composite and the improvement is more significant in case of PbO compared to CuO of the same filler wt.% at the same energy. The results also demonstrated an enhancement in the radiation protection behavior of rPVC composites due to the addition of PbO and CuO fillers as nano-sized particles.
A mathematical model of enzymatic non-competitive inhibition by product and its applications
Authors: Mai Vinh Quang , Nhan Thái Anh , Hammouch Zakia 
Published: November 2021

Abstract
Enzymes are biological catalysts naturally present in living organisms, and they are capable of accelerating biochemical reactions in the metabolism process. Cells use many regulatory mechanisms to regulate the concentrations of cellular metabolites at physiological levels. Enzymatic inhibition is one of the key regulatory mechanisms naturally occurring in cellular metabolism, especially the enzymatic non-competitive inhibition by product. This inhibition process helps the cell regulate enzymatic activities. In this paper, we develop a novel mathematical model describing the enzymatic non-competitive inhibition by product. The model consists of a coupled system of nonlinear ordinary differential equations for the species of interest. Using nondimensionalization analysis, a formula for product formation rate for this mechanism is obtained in a transparent manner. Further analysis for this formula yields qualitative insights into the maximal reaction velocity and apparent Michaelis-Menten constant. Asymptotic solutions of the model are carefully given by using the homotopy perturbation analysis. A good agreement between the asymptotic solutions and numerical solutions are found. In addition, a Sobol global sensitivity analysis is implemented to help identify the key mechanisms of the enzyme activities. The results of this analysis show that the rate of product formation is relatively sensitive to the following factors: the catalytic rate of the enzyme, the rates of binding/unbinding of the product to/from the enzyme/enzyme complex. The numerical simulations provide insights into how variations in the model parameters affect the model output. Finally, an application of the model to the phosphorylation of glucose by mutant-hexokinase I enzyme is briefly discussed.
Finding sound shells in LISA mock data using likelihood sampling
Authors: Giese Felix , Konstandin Thomas , van de Vis Jorinde 
Published: November 2021

Abstract
We study to what extent LISA can observe features of gravitational
wave spectra originating from cosmological first-order phase transitions.
We focus on spectra which are of the form of double-broken power laws.
These spectra are predicted by hydrodynamic simulations and also analytical models such as
the sound shell model. We argue that the ratio of the two break frequencies is
an interesting observable since it can be related to the wall velocity
while overall amplitude and frequency range are often degenerate for the numerous
characteristics of the phase transition. Our analysis uses mock data obtained from the power spectra predicted by the simplified simulations and the sound shell model and analyzes the detection prospects using χ2-minimization and likelihood sampling. We point out that the prospects of observing
two break frequencies from the electroweak phase transition is hindered by a shift of the spectrum to smaller frequencies for strong phase
transitions. Finally, we also highlight some
differences between signals from the sound shell model compared to simulations.
Possible dibaryon production at

anda with a Lagrangian approach *
Authors: Dong Yubing , Shen Pengnian 
Published: November 2021

Abstract
In order to confirm the existence of the dibaryon state

observed at WASA@COSY, we estimate the cross section for production of the possible dibaryon and anti-dibaryon pair

in the energy region of the upcoming experiments at

anda. Based on some qualitative properties of

extracted from the analyses in the non-relativistic quark model, the production cross section for this spin-3 particle pair are calculated with the help of a phenomenological effective relativistic and covariant Lagrangian approach.
EEG-based brain–computer interfaces exploiting steady-state somatosensory-evoked potentials: a literature review
Authors: Petit Jimmy , Rouillard José , Cabestaing François 
Published: November 2021

Abstract
A brain–computer interface (BCI) aims to derive commands from the user’s brain activity in order to relay them to an external device. To do so, it can either detect a spontaneous change in the mental state, in the so-called ‘active’ BCIs, or a transient or sustained change in the brain response to an external stimulation, in ‘reactive’ BCIs. In the latter, external stimuli are perceived by the user through a sensory channel, usually sight or hearing. When the stimulation is sustained and periodical, the brain response reaches an oscillatory steady-state that can be detected rather easily. We focus our attention on electroencephalography-based BCIs (EEG-based BCI) in which a periodical signal, either mechanical or electrical, stimulates the user skin. This type of stimulus elicits a steady-state response of the somatosensory system that can be detected in the recorded EEG. The oscillatory and phase-locked voltage component characterising this response is called a steady-state somatosensory-evoked potential (SSSEP). It has been shown that the amplitude of the SSSEP is modulated by specific mental tasks, for instance when the user focuses their attention or not to the somatosensory stimulation, allowing the translation of this variation into a command. Actually, SSSEP-based BCIs may benefit from straightforward analysis techniques of EEG signals, like reactive BCIs, while allowing self-paced interaction, like active BCIs. In this paper, we present a survey of scientific literature related to EEG-based BCI exploiting SSSEP. Firstly, we endeavour to describe the main characteristics of SSSEPs and the calibration techniques that allow the tuning of stimulation in order to maximise their amplitude. Secondly, we present the signal processing and data classification algorithms implemented by authors in order to elaborate commands in their SSSEP-based BCIs, as well as the classification performance that they evaluated on user experiments.
Skilled independent control of individual motor units via a non-invasive neuromuscular–machine interface
Authors: Formento Emanuele , Botros Paul , Carmena Jose M 
Published: November 2021

Abstract

Objective. Brain–machine interfaces (BMIs) have the potential to augment human functions and restore independence in people with disabilities, yet a compromise between non-invasiveness and performance limits their relevance. Approach. Here, we hypothesized that a non-invasive neuromuscular–machine interface providing real-time neurofeedback of individual motor units within a muscle could enable independent motor unit control to an extent suitable for high-performance BMI applications. Main results. Over 6 days of training, eight participants progressively learned to skillfully and independently control three biceps brachii motor units to complete a 2D center-out task. We show that neurofeedback enabled motor unit activity that largely violated recruitment constraints observed during ramp-and-hold isometric contractions thought to limit individual motor unit controllability. Finally, participants demonstrated the suitability of individual motor units for powering general applications through a spelling task. Significance. These results illustrate the flexibility of the sensorimotor system and highlight individual motor units as a promising source of control for BMI applications.
Siberian 2020 heatwave increased spring CO2 uptake but not annual CO2 uptake
Authors: Kwon Min Jung , Ballantyne Ashley , Ciais Philippe , Bastos Ana , Chevallier Frédéric , Liu Zhihua , Green Julia K , Qiu Chunjing , Kimball John S 
Published: November 2021

Abstract
Siberia experienced an unprecedented strong and persistent heatwave in winter to spring of 2020. Using bottom–up and top–down approaches, we evaluated seasonal and annual CO2 fluxes of 2020 in the northern hemisphere (north of 30 °N), focusing on Siberia where the pronounced heatwave occurred. We found that, over Siberia, CO2 respiration loss in response to the pronounced positive winter temperature anomaly was greater than in previous years. However, continued warming in the spring enhanced photosynthetic CO2 uptake, resulting in the largest seasonal transition in net ecosystem CO2 exchange; that is, the largest magnitude of the switch from the net CO2 loss in winter to net CO2 uptake in spring until June. However, this exceptional transition was followed by the largest reduction in CO2 uptake in late summer due to multiple environmental constraints, including a soil moisture deficit. Despite a substantial increase of CO2 uptake by 22 ± 9 gC m−2 in the spring in response to the heatwave, the mean annual CO2 uptake over Siberia was slightly lower (3 ± 13 gC m−2yr−1) than the average of the previous five years. These results highlight the highly dynamic response of seasonal carbon fluxes to extreme temperature anomalies at high latitudes, indicating a seasonal compensation between abnormal uptake and release of CO2 in response to extreme warmth that may limit carbon sink capacity in high northern latitudes.
Indices Extraction from Multitemporal Remote Sensing Data for Mapping Urban Built-Up
Authors: Hayati A. K. , Hestrio Y.F. , Cendiana N. , Kustiyo K. 
Published: November 2021

Abstract
Remote sensing data analysis in the cloudy area is still a challenging process. Fortunately, remote sensing technology is fast growing. As a result, multitemporal data could be used to overcome the problem of the cloudy area. Using multitemporal data is a common approach to address the cloud problem. However, most methods only use two data, one as the main data and the other as complementary of the cloudy area. In this paper, a method to harness multitemporal remote sensing data for automatically extracting some indices is proposed. In this method, the process of extracting the indices is done without having to mask the cloud. Those indices could be further used for many applications such as the classification of urban built-up. Landsat-8 data that is acquired during 2019 are stacked, therefore each pixel at the same position creates a list. From each list, indices are extracted. In this study, NDVI, NDBI, and NDWI are used to mapping built-up areas. Furthermore, extracted indices are divided into four categories by their value (maximum, quantile 75, median, and mean). Those indices are then combined into a simple formula to mapping built-up to see which produces better accuracy. The Pleiades as high-resolution remote sensing data is used to assist supervised classification for assessment. In this study, the combination of mean NDBI, maximum NDVI, and mean NDWI result highest Kappa coefficient of 0.771.
Assessment of Rapid Urban Development Impact for a Small-Sized Transit City Using Remote Sensing: A Case Study of Salatiga, Indonesia
Authors: Dewa D. D. , Buchori I. 
Published: November 2021

Abstract
Salatiga is the connecting city between Semarang City and Surakarta, which makes it one of the small-sized transit cities in Central Java. Its strategic location has led to various developments being carried out in Salatiga in the last ten years. This study aimed to assess the impact of the rapid development of Salatiga as a transit city. This study utilized remote sensing to analyze land cover changes and changes in land surface temperature (LST). The results showed that Salatiga experienced more significant growth in the built-up area than the population growth. The rapid development in Salatiga creates various new activities, such as trade and services and industries. This development changed the land cover and affected the land surface temperature in Salatiga. In the last ten years, Salatiga experienced an average temperature increase of 0.23°C. Mitigation efforts are needed to suppress environmental changes in the future.