bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sex differences in muscle excitation and oxygenation, but not in force fluctuations or active hyperemia resulting from a fatiguing, bilateral isometric task
Authors: Keller Joshua L , Anders John Paul V , Neltner Tyler J , Housh Terry J , Schmidt Richard J , Johnson Glen O 
Published: December 2021

Abstract
It remains to be fully elucidated if there are sex-specific physiological adjustments within the human neuromuscular and vascular systems that contribute to symptoms of fatigue during a sustained bilateral task. This, in part, is likely due to various limitations in experimental design such as an inability to independently record force fluctuations from each limb. Objective. Therefore, the purpose of the current study was to examine the fatigue-induced changes in muscle excitation, force fluctuations, skeletal muscle tissue saturation (StO2), and muscle blood flow resulting from a sustained, bilateral task. Approach. Thirty healthy, college-aged adults (15 males, 15 females) performed a bilateral leg task at 25% of maximum voluntary isometric (MVIC). Before and after the task, MVICs were completed. Resting and post-task femoral artery blood flow (FABF) were determined. Muscle excitation was quantified as electromyographic amplitude (EMG AMP) from the right and left vastus lateralis. During the task, force fluctuations were determined independently from each leg. The StO2 signal was collected with a near-infrared spectroscopy device attached to the right vastus lateralis. The rate of change in these variables was calculated via simple linear regression. The exercise-induced magnitude of change in MVIC (i.e. performance fatigability) and FABF (i.e. active hyperemia) was determined. Main Results. There was no sex difference in the percent decline in MVIC (20.5 ± 20.1% versus 16.4 ± 3.5%; p > 0.05). There were no inter-leg differences in EMG AMP or force fluctuations. The males exhibited a faster rate of increase in EMG AMP (b = 0.13 versus b = 0.08; p < 0.001), whereas the females exhibited a slower rate of decline in StO2 (b = −0.049 versus b = −0.080). There was no sex difference in force fluctuations or change in FABF. Significance. Males and females likely have different neuromuscular strategies and muscle characteristics, but these did not elicit a sex difference in performance fatigability.
Vascular ageing and peripheral pulse: an improved model for assessing their relationship
Authors: Aliani Cosimo , Rossi Eva , Francia Piergiorgio , Bocchi Leonardo 
Published: December 2021

Abstract

Objective. Vascular ageing is associated with several alterations, including arterial stiffness and endothelial dysfunction. Such alterations represent an independent factor in the development of cardiovascular disease (CVD). In our previous works we demonstrated the alterations occurring in the vascular system are themselves reflected in the shape of the peripheral waveform; thus, a model that describes the waveform as a sum of Gaussian curves provides a set of parameters that successfully discriminate between under (≤35 years old) and over subjects (>35 years old). In the present work, we explored the feasibility of a new decomposition model, based on a sum of exponential pulses, applied to the same problem. Approach. The first processing step extracts each pulsation from the input signal and removes the long-term trend using a cubic spline with nodes between consecutive pulsations. After that, a Least Squares fitting algorithm determines the set of optimal model parameters that best approximates each single pulse. The vector of model parameters gives a compact representation of the pulse waveform that constitutes the basis for the classification step. Each subject is associated to his/her ‘representative’ pulse waveform, obtained by averaging the vector parameters corresponding to all pulses. Finally, a Bayesan classifier has been designed to discriminate the waveforms of under and over subjects, using the leave-one-subject-out validation method. Main results. Results indicate that the fitting procedure reaches a rate of 96% in under subjects and 95% in over subjects and that the Bayesan classifier is able to correctly classify 91% of the subjects with a specificity of 94% and a sensibility of 84%. Significance. This study shows a sensible vascular age estimation accuracy with a multi-exponential model, which may help to predict CVD.
Robust wave-feature adaptive heartbeat classification based on self-attention mechanism using a transformer model
Authors: Hu Shuaicong , Cai Wenjie , Gao Tijie , Zhou Jiajun , Wang Mingjie 
Published: December 2021

Abstract

Objective. Electrocardiography is a common method for screening cardiovascular diseases. Accurate heartbeat classification assists in diagnosis and has attracted great attention. In this paper, we proposed an automatic heartbeat classification method based on a transformer neural network using a self-attention mechanism. Approach. An adaptive heartbeat segmentation method was designed to selectively focus on the time-dependent representation of heartbeats. A one-dimensional convolution layer was used to embed wave characteristics into symbolic representations, and then, a transformer block using multi-head attention was applied to deal with the dependence of wave-embedding. The model was trained and evaluated using the MIT-BIH arrhythmia database (MIT-DB). To improve the model performance, the model pre-trained on MIT-BIH supraventricular arrhythmia database (MIT-SVDB) was used and fine-tuned on MIT-DB. Main results. The proposed method was verified using the MIT-DB for two groups. In the first group, our method attained F1 scores of 0.86 and 0.96 for the supraventricular ectopic beat class and ventricular ectopic beat class, respectively. In the second group, our method achieved an average F1 value of 99.83% and better results than other state-of-the-art methods. Significance. We proposed a novel heartbeat classification method based on a transformer model. This method provides a new solution for real-time electrocardiogram heartbeat classification, which can be applied to wearable devices
Analytical model for 2DEG charge density in β-(Al
x
Ga1−x
)2O3/Ga2O3 HFET
Authors: Patnaik Akash , Jaiswal Neeraj K , Singh Rohit , Sharma Pankaj 
Published: December 2021

Abstract
In this paper, a physics-based analytical model for two-dimensional electron gas (2DEG) charge density (n
s) and pinch-off voltage (V
off) in

β

-(Al
x
Ga1−x
)2O3/Ga2O3 heterostructure field effect transistor (HFET) is reported. The modeling approach includes solving the Poisson–Schrödinger equation in

β

-(Al
x
Ga1−x
)O3 barrier layer followed by using standard Fermi–Dirac statistics equations for calculating 2DEG charge density in the potential well. The developed model is then used to analyze the effect of Al composition (x) and barrier thickness (d) of

β

-(Al
x
Ga1−x
)2O3 layer on 2DEG charge density. The obtained parameters from our model for charge density and pinch-off voltages are validated with the experimental results in the literature demonstrating a good accuracy. It was observed that the 2DEG charge density increases with Al composition and Al
x
Ga1−x
O barrier layer thickness, but at the cost of increased pinch off voltage. A trade-off between both is necessary to achieve parametric optimization of

β

-(Al
x
Ga1−x
)2O3/Ga2O3 HFET. This model will be useful to study the various parametric constraints for device optimization in terms of 2DEG charge density and pinch off voltage.
A novel piezoelectric-actuated microgripper simultaneously integrated microassembly force, gripping force and jaw-displacement sensors: design, simulation and experimental investigation
Authors: Wang Kan , Wang Dai-Hua , Zhao Jian-Yu , Hou Song 
Published: December 2021

Abstract
For assembling easy-to-deform and easy-to-broken micropart, accurate acquisition of microassembly force and gripping force during microassembly process while ensuring parallel movement of jaws of microgripper is the key to ensure consistency, accuracy and reliability of microassembly without damage. In addition, simultaneously real-time detection of jaw-displacement of microgripper is also a necessary condition for rapid and accurate microassembly. This paper proposes and realizes a principle of a parallelogram compliant mechanism (PCM) based piezoelectric-actuated microgripper, which simultaneously integrates with microassembly force, gripping force and jaw-displacement sensors for the first time and ensures parallel movement of jaws under no-load and gripping micropart. The major structure of proposed microgripper is a monolithic compliant mechanism (MCM) composed of a primary lever compliant mechanism and three-stage PCM in series. Among them, the third-stage PCM is orthogonal to other two PCM in series. MCM transmits the displacement and force from piezoelectric actuator to jaws while transforming microassembly force, gripping force and jaw-displacement into surface strain of single-notch hinges of PCM with three-stage in series. On this basis, simultaneously sensing microassembly force, gripping force and jaw-displacement is realized by monitoring surface strain of single-notch hinges of three-stage PCM. The sensing equations of the microassembly force, gripping force, and jaw-displacement are established, respectively. A microgripper is manufactured, a microgripper system is realized and the integrated sensors are calibrated. The hysteresis characteristics, creep characteristics and time response are tested experimentally. Two examples of microassembly sub-process are simulated and carried out on the constructed microassembly experimental setup. The theoretical and experimental results show that the designed microgripper can simultaneously acquire the microassembly force, gripping force and jaw-displacement with high sensitivity, linearity and resolution in processes of gripping hohlraum and applying microassembly force to hohlraum while ensuring the parallel movement of the gripping jaws when gripping and not gripping micropart.
A high-resolution electric field sensor based on piezoelectric bimorph composite
Authors: Cheng Miaomiao , Wu Jingen , Guan Mengmeng , Mao Qi , Xian Dan , Hu Zhongqiang , Wang Chenying , Wang Zhiguang , Zhou Ziyao , Zhao Libo , Jiang Zhuangde , Liu Ming 
Published: December 2021

Abstract
The rapid development of the internet of things technology has led to great demand for intelligent electric field sensor (EFS). Several working principles have been proposed, however major challenges remain existed for the requirements of EFS with low-cost, large-range, and high-resolution. In this paper, an EFS based on piezoelectric (PE) bending effect using d
31 mode is developed, where a bending strain is induced on the sandwiched bimorph structure of PZT/PDMS/PZT under an applied electric field, and the capacitance value of the PDMS layer reveals detectable variation. We demonstrate an EFS operating at the stress-mediated coupling between PE ceramic and elastic dielectric polymer, which reveals advantages such as simple fabrication process, low-cost and low power consumption. Due to the sandwiched bimorph structure, the strain caused by the electric field can be effectively transferred to improve the resolution of the device. The constitutive equations for the sandwiched bimorph structure are built, and the working principle of the proposed EFS is demonstrated. The EFS exhibits high sensitivity under both AC and DC electric fields, with a resolution of 0.1 V cm−1 in the range of −3 to 3 kV cm−1. The proposed sensor provides an alternative solution for power equipment fault diagnosis, power frequency electric field detection, etc.
The topological counterparts of non-Hermitian SSH models
Authors: Han Y Z , Liu J S , Liu C S 
Published: December 2021

Abstract
Inspired by the relevance between the asymmetric coupling amplitude and the imaginary gauge field, we construct the counterpart of the non-Hermitian SSH model. The idea is the nonzero imaginary magnetic flux vanishing when the boundary condition changes from periodic to open. The zero imaginary magnetic flux of the counterpart leads to the eliminating of the non-Hermitian skin effect and the non-Hermitian Aharonov–Bohm effect which ensures the recovery of the conventional bulk-boundary correspondence from the non-Bloch bulk-boundary correspondence. We explain how some the non-Hermitian models can be transformed to the non-Hermitian SSH models and how the non-reciprocal hopping in the non-Hermitian SSH models can be transformed from one term to the other terms by the similarity transformations. We elaborate why the effective imaginary magnetic flux disappears due to the interplay of the non-reciprocal hoppings in the partner of the non-Hermitian SSH model. As the results, we obtain the topological invariants of the non-Hermitian SSH model in analytical form defined in conventional Brillouin zone. The non-Hermitian SSH model in domain configuration on a chain is discussed with this method. The technique gives an alternative way to study the topological properties of non-Hermitian systems.
Topological pumping in acoustic waveguide arrays with hopping modulation
Authors: Chen Zhaoxian , Chen Zeguo , Li Zhengwei , Liang Bin , Ma Guancong , Lu Yanqing , Cheng Jianchun 
Published: December 2021

Abstract
Thouless pumping is the adiabatic transportation of quantized charge, which is regarded as the dynamic version of the quantum Hall effect. Here we propose the design of an acoustic system to demonstrate the topological pumping characterized by transporting acoustic energy from one side to the opposite. The system is composed of coupled acoustic waveguide arrays with modulated coupling along both cross-sections and the propagating direction. We explore multiple topological phases by introducing rich spatial frequency or enlarged range of the hopping modulation. Such distinct topological phases are evidenced by adiabatic evolution of the edge states, where the acoustic system varies continuously and slowly along the state propagating direction. The robustness behavior of the edge states transport is also verified with numerical simulations to imply their topology origin. Our work provides a route to realize topological phases and utilize the corresponding edge states in waveguide arrays that can lead to versatile acoustic wave manipulation applications.
Quantum homotopy perturbation method for nonlinear dissipative ordinary differential equations
Authors: Xue Cheng , Wu Yu-Chun , Guo Guo-Ping 
Published: December 2021

Abstract
While quantum computing provides an exponential advantage in solving linear differential equations, there are relatively few quantum algorithms for solving nonlinear differential equations. In our work, based on the homotopy perturbation method, we propose a quantum algorithm for solving n-dimensional nonlinear dissipative ordinary differential equations (ODEs). Our algorithm first converts the original nonlinear ODEs into the other nonlinear ODEs which can be embedded into finite-dimensional linear ODEs. Then we solve the embedded linear ODEs with quantum linear ODEs algorithm and obtain a state ϵ-close to the normalized exact solution of the original nonlinear ODEs with success probability Ω(1). The complexity of our algorithm is O(gηT poly(log(nT/ϵ))), where η, g measure the decay of the solution. Our algorithm provides exponential improvement over the best classical algorithms or previous quantum algorithms in n or ϵ.
Quantum communication for sender anonymity based on single-particle with collective detection
Authors: Li Yuancheng , Yu Chaohang , Wang Qingle , Liu Jiangshan 
Published: December 2021

Abstract
Nowadays, identity protection has turned into a fundamental demand for online activities. Currently, the present quantum anonymous communication protocols mostly rely on multi-entanglement. In this paper, we propose an anonymous communication protocol for anonymous sender by using single-particle states. The protocol can be extended to a communication protocol where the sender and receiver are fully anonymous with the message kept secret. In terms of security, our protocol is designed to comply with the technique of collective detection. Compared to the step-by-step detection, collective detection, in which the participants perform detection only once, reduces the complexity of the protocol to some extent. Moreover, we analytically demonstrate the security of the protocol in the face of active attacks. Any active attack employed by an external or internal attacker cannot reveal any useful information about the sender’s identity. Meanwhile, any malicious behavior will be detected by honest participants.
Strain-engineering in AlGaN/GaN HEMTs: impact of silicon nitride passivation layer on electrical performance
Authors: Das Sanghamitra , Dash Tara Prasanna , Jena Devika , Mohapatra Eleena , Maiti Chinmay Kumar 
Published: December 2021

Abstract
In this work, we present a physics-based analysis of two-dimensional electron gas (2DEG) sheet carrier density and other microwave characteristics such as transconductance and cutoff frequency of AlxGa1−xN/GaN high electron mobility transistors (HEMT). An accurate polarization-dependent charge control-based analysis is performed for microwave performance assessment in terms of current, transconductance, gate capacitances, and cutoff frequency of lattice-mismatched AlGaN/GaN HEMTs. The influence of stress on spontaneous and piezoelectric polarization is included in the simulation of an AlGaN/GaN HEMT. We have shown the change in threshold voltage (Vt) due to tensile and compressive strain with different gate lengths. Also, the influence of stress due to the change in nitride thickness is presented. Our simulation results for drain current, transconductance, and current-gain cutoff frequency for various gate length devices are calibrated and verified with experimental data over a wide range of gate and drain applied voltages, which are expected to be useful for microwave circuit design. The predicted transconductance, drain conductance, and operation frequency are quite close to the experimental data. The AlGaN/GaN heterostructure HEMTs with nitride passivation layers show great promise as a candidate in future high speed and high power applications.
Testing the consistency between cosmological data: the impact of spatial curvature and the dark energy EoS
Authors: Gonzalez Javier E. , Benetti Micol , von Marttens Rodrigo , Alcaniz Jailson 
Published: December 2021

Abstract
The results of joint analyses of available cosmological data
have motivated an important debate about a possible detection of a
non-zero spatial curvature. If confirmed, such a result would imply
a change in our present understanding of cosmic evolution with
important theoretical and observational consequences. In this paper
we discuss the legitimacy of carrying out joint analyses with the
currently available data sets and explore their implications for a
non-flat universe and extensions of the standard cosmological model.
We use a robust tension estimator to perform a quantitative analysis
of the physical consistency between the latest data of Cosmic
Microwave Background, type Ia supernovae, Baryonic Acoustic
Oscillations and Cosmic Chronometers. We consider the flat and
non-flat cases of the ΛCDM cosmology and of two dark energy
models with a constant and varying dark energy EoS parameter. The
present study allows us to better understand if possible
inconsistencies between these data sets are significant enough to
make the results of their joint analyses misleading, as well as the
actual dependence of such results with the spatial curvature and
dark energy parameterizations. According to our results, we conclude
that a joint analysis in the context of a non-flat universe
including the CMB data is only possible if the CMB Lens is taken
into account, otherwise, it potentially leads to misleading
conclusions.
Analytical warm dark matter power spectrum on small scales
Authors: Pordeus-da-Silva G. , Batista R.C. , Medeiros L.G. 
Published: December 2021

Abstract
Using the Reduced Relativistic Gas (RRG) model, we analytically determine
the matter power spectrum for Warm Dark Matter (WDM) on small scales,
k > 1 h/Mpc. The RRG is a simplified model for the ideal relativistic
gas, but very accurate in the cosmological context. In another work,
we have shown that, for typical allowed masses for dark matter particles,
m>5 keV, the higher order multipoles, ℓ ≥ 2, in the Einstein-Boltzmann
system of equations are negligible on scales k < 10 h/Mpc.
Hence, we can follow the perturbations of WDM using the ideal fluid
framework, with equation of state and sound speed of perturbations
given by the RRG model. We derive a Mészáros-like equation for WDM
and solve it analytically in radiation, matter and dark energy dominated
eras. Joining these solutions, we get an expression that determines
the value of WDM perturbations as a function of redshift and wavenumber.
Then we construct the matter power spectrum and transfer function
of WDM on small scales and compare it to some results coming from
Lyman-α forest observations. Besides being a clear and pedagogical
analytical development to understand the evolution of WDM perturbations,
our power spectrum results are consistent with the observations considered
and the other determinations of the degree of warmness of dark matter particles.
Blandford-Znajek mechanism in the general stationary axially-symmetric black-hole spacetime
Authors: Konoplya R.A. , Kunz J. , Zhidenko A. 
Published: December 2021

Abstract
We consider the Blandford-Znajek process of electromagnetic extraction of energy from a general axially symmetric asymptotically flat slowly rotating black hole. Using the general parametrization of the black-hole spacetime we construct formulas for the flux of the magnetic field and the rate of energy extraction, which are valid not only for the Kerr spacetime, but also for its arbitrary axially symmetric deformations. We show that in the dominant order these quantities depend only on a single deformation parameter, which relates the spin frequency of a black hole with its rotation parameter.
High-confinement radiative L-modes in ASDEX Upgrade
Authors: Fable E. , Kallenbach A. , McDermott R.M. , Bernert M. , Angioni C. , the ASDEX Upgrade Team  
Published: December 2021

Abstract
Experiments have been performed in the ASDEX Upgrade tokamak where plasmas are kept just below the H-mode threshold using feedback on the radiated power via seeded impurity. The resulting high-power L-modes show high confinement properties and no ELM activity due to the reduced pedestal height. The physics of these high-confinement L-modes is explored by means of integrated modeling to clarify the origin of the improved confinement.
Neoclassical toroidal viscosity torque prediction via deep learning
Authors: Clement M.D. , Logan N.C. , Boyer M.D. 
Published: December 2021

Abstract
GPECnet is a densely connected neural network that has been trained on GPEC data, to predict the plasma stability, neoclassical toroidal viscosity (NTV) torque, and optimized 3D coil current distributions for desired NTV torque profiles. Using NTV torque, driven by non-axisymmetric field perturbations in a tokamak, can be vital in optimizing pedestal performance by controlling the rotation profile in both the core, to ensure tearing stability, and the edge, to avoid edge localized modes (ELMs). The generalized perturbed equilibrium code (GPEC) software package can be used to calculate the plasma stability to 3D perturbations and the NTV torque profile generated by applied 3D magnetic fields. These calculations, however, involve complex integrations over space and energy distributions, which takes time to compute. Initially, GPECnet has been trained solely on data representative of the quiescent H-mode (QH) scenario, in which neutral beams are often balanced and toroidal rotation is low across the plasma profile. This work provides the foundation for active control of the rotation shear using a combination of beams and 3D fields for robust and high performance QH mode operation.