bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of a biomimetic wing from maple samara and investigation of the aerodynamic performance
Authors: Çalışkan Mehmet E. , Kaya Fuat , Sabırlı Muhammet U. , Karagoz Irfan
Published: September 2023

The morphological structure and airborne behavior of maple samaras have attracted increasing attention due to their potential use in wind turbines and air vehicles. This study introduces a new methodology based on mathematical modeling to transfer the geometric structure of maple samaras to a virtual environment and presents an experimental and numerical investigation of the performance of a model wing designed with this method. Certain sections were taken along the structure of maple samaras, measurements were made, curves were obtained mathematically for each section, and these curves were transferred to a design program. A biomimetic three-dimensional model was generated by combining these curves. The mathematical modeling of these curves was obtained with certain degrees of expansion of the Fourier series. Experimental and numerical studies of the designed biomimetic model were performed at different free stream velocities and angles of attack. The trend of the lift coefficient curves indicated that the samara wing model has a larger range of angle of attack, up to 40°–45° without a stall, and the maximum lift to drag ratio (CL/CD) was obtained at 8° angle of attack. In addition, the present model showed more stable performance, and the lift and drag forces did not change as much as in conventional blades at varying free flow velocities. In the analysis results, the air flowing over the wing caused the formation of these vortices inside the ordered trough top structures of the model. These vortices, seen from the leading edge, are thought to play an effective role in the lift coefficient of the biomimetic samara model.
Wave-heat-electricity conversion: Design and analysis of an electromagnetic energy conversion device
Authors: Xiong Han , Ma Xiaodong , Zhang Huaiqing
Published: September 2023

An innovative electromagnetic energy harvester was developed using a compact four-ring single-resistor unit cell. To achieve efficient conversion of electromagnetic waves into electricity, we integrated the high-performance Bi2Te3 thermoelectric material onto the load resistor. Remarkably, this unit cell exhibits exceptional energy harvesting capabilities at a frequency of 5.8 GHz while maintaining polarization insensitivity. Through comprehensive analysis, we evaluated the energy harvesting efficiencies, power loss distribution, and current density distribution. Additionally, we investigated the impact of incident power on the unit cell's temperature and energy conversion efficiencies. To enhance energy concentration on the load, we ingeniously designed an “L-shaped” metal through-hole structure within the four-ring single-resistor unit cell. Our results demonstrate that the four-ring single-resistor unit cell achieves an impressive harvesting efficiency of 94.5% at 5.8 GHz, with a thermal conversion efficiency of 43.3 °C/W, an electrical conversion efficiency of 0.23 mV/°C, and an electrical response rate of 9.4 mV/W. Notably, when subjected to a power input of 7 W, the unit cell produces an output voltage of 65.9 mV, and its theoretical maximum output power reaches 180 mW.
First-principles study of controllable contact types in Janus MoSH/GaN van der Waals heterostructure
Authors: Liu Yutao , Gao Tinghong
Published: September 2023

The search for contact materials with low contact resistance and tunable Schottky barrier (SB) height of two-dimensional (2D) materials is important for improving the electronic performance. Inspired by the recently synthesized metallic Janus MoSH, this study employs first-principles calculations to investigate the electronic structure, mechanical properties, and interface characteristics of Janus MoSH/GaN and MoHS/GaN van der Waals (vdW) heterostructures. We find that both heterostructures exhibit isotropic mechanical properties and form p-type Schottky barrier contacts (p-ShC) and the SB height of MoHS/GaN is smaller than that of the MoSH/GaN heterostructure. The variation in SB height and contact type under biaxial strain and electric field is also studied for both vdW heterostructures, respectively. Compared to the MoSH/GaN heterostructure, the MoHS/GaN heterostructure can transition to Ohmic contact (OhC) under biaxial strain and electric field, making the S-face contact of MoSH with GaN a more effective contact approach. These findings could provide a new pathway for the design of controllable Schottky nanodevices and high-performance electronic devices on GaN-based vdW heterostructures.
On non-Newtonian fluid flow generated via complex metachronal waves of cilia with magnetic, hall, and porous effects
Authors: Asghar Zeeshan , Khan Muhammad Waris Saeed , Pasha Amjad Ali , Rahman Mustafa Mutiur , Sankaralingam L. , Alam Mohammad Irfan
Published: September 2023

Cilia beating influences bio-fluid flow, and conduits with ciliated surfaces serve numerous purposes. Cilia are hair-like adjuncts that produce liquid drive and cell locomotion. This novel research integrates magnetohydrodynamics, Hall effects, and porous medium with the cilia-driven flow. The developed problem is further simplified by utilizing famous assumptions, i.e., low Reynolds number and large wavelength. The bvp5c function in MATLAB (2023a) is adopted to achieve a convergent solution. The graphical illustrations of streamlines, pressure drop, and axial velocity under the influence of pertinent parameters are thoroughly examined. The findings suggest that when a high magnetic field (Hall current) and porous media are combined with the Carreau–Yasuda fluid, the pumping equipment operates better than the viscous liquid. In addition, fluid movement in biological organs is improved by metachronal ciliary motion. Furthermore, it is predicted that this study will make a significant contribution to biomedical engineering in terms of the upgrading and advancement of various types of drug-delivery technologies.
Flow structure and vortex dynamics of blade surface transitional flow in the near-tip region of a compressor cascade
Authors: Shi Lei , Mao Ruiqing , Ma Hongwei , Wang Tianyou
Published: September 2023

The mean flow topology and vortex dynamics of the blade surface transitional flow in the near-tip region of a C4 compressor blade were investigated using particle image velocimetry measurements with two configurations. The experiment was conducted in a compressor cascade at a chord Reynolds number of 24 000 and an incidence angle of 0°, and a laminar separation bubble was detected on the aft portion of the blade. In the half-span region of the blade, the separation is essentially two-dimensional without reattachment. The vortex dynamics are dominated by the periodic shedding of separated shear layer vortices and their interaction with the trailing edge vortices. The progressive spanwise evolution in the flow structures and vortex dynamics occur near the blade tip (70%–80% blade height), leading to an advanced, thinner separation. In contrast, the tip leakage vortex dominated region is restricted to approximately 20% of blade height from the blade tip. In this region, secondary flow effects are intensive enough to prevent laminar separation. Between the above two regions, there is a transition region (90% blade height), where the influence of the tip flow on the blade surface flow is relatively slight that merely suppresses the vortex shedding of the separated boundary layer, nor the whole shear layer. In the transition region, the velocity fluctuations are significantly reduced.
Electronic structure and magnetothermal property of two-dimensional ferromagnetic NbSe2 monolayer regulated by carrier concentration
Authors: Wu Yan-Ling , Wu Hao-Jia , Geng Hua-Yun , Cheng Yan
Published: September 2023

Investigating high-performance and stable spintronics devices has been a research hotspot in recent years. In this paper, we employed first-principles methods and Monte Carlo (MC) simulations to explore the structure, electronic, and magnetic properties of monolayer NbSe2, as well as its behavior under carrier concentration modulation. The research on the electronic structure reveals that by introducing an appropriate amount of holes, the material can undergo a transition from metal to a half-metal state, achieving 100% high spin polarization. Investigation of magnetic crystalline anisotropy shows that the magnetic crystal anisotropy energy of 1210 μeV in out-of-plane is beneficial to maintain ferromagnetic order at high temperatures. In addition, doping with suitable carriers can effectively enhance or strengthen the ferromagnetic coupling in NbSe2 so that the magnetization easy axis is shifted. This reveals the potential application prospects of NbSe2 in electronically controlled spintronic devices. Analysis of the Fermi surface shows that both holes and electron doping increase the Fermi velocity of the material. The effect of hole doping is particularly significant, indicating its potential application in Fermi velocity engineering. Under the theoretical framework of the extended two-dimensional Ising model, based on MC simulation, the Curie temperature (TC) of NbSe2 is predicted to be 162 K. The effects of carrier concentration and the magnetic field on the magnetic and thermal properties of monolayer NbSe2 are simulated. The results show that appropriately increasing the hole doping concentration and magnetic field is conducive to obtaining ferromagnetic half-metallic materials with TC higher than room temperature, which provides theoretical support for experimental preparation.
A physics-informed deep learning model of the hot tail runaway electron seed
Authors: McDevitt Christopher J.
Published: September 2023

A challenging aspect of the description of a tokamak disruption is evaluating the hot tail runaway electron seed that emerges during the thermal quench. This problem is made challenging due to the requirement of describing a strongly non-thermal electron distribution, together with the need to incorporate a diverse range of multiphysics processes, including magnetohydrodynamic instabilities, impurity transport, and radiative losses. This work develops a physics-informed neural network (PINN) tailored to the solution of the hot tail seed during an axisymmetric thermal quench. Here, a PINN is developed to identify solutions to the adjoint relativistic Fokker–Planck equation in the presence of a rapid quench of the plasma's thermal energy. It is shown that the PINN is able to accurately predict the hot tail seed across a range of parameters, including the thermal quench timescale, initial plasma temperature, and local current density, in the absence of experimental or simulation data. The hot tail PINN is verified by comparison with direct Monte Carlo simulations, with excellent agreement found across a broad range of thermal quench conditions.
Hierarchical approximations to the nucleation work in the entire range of metastability
Authors: Kashchiev Dimo
Published: September 2023

The work W to form a nucleus (also known as the critical nucleus) is a key quantity in the description of nucleation phenomena because of its exponentially strong effect on the nucleation rate. The present study provides a general approximate expression for W, which comprises a hierarchy of approximations to the dependence of W on the experimentally controlled overpressure Δp of a nucleating multicomponent phase. This general expression is used to derive explicit formulas for the lowest-order members of the W(Δp) hierarchy as well as for the respective lowest-order approximations to the Δp dependences of the nucleus surface tension, the nucleus radius, the Gibbs–Tolman length, and the stationary nucleation rate. The second-order and the third-order approximations to the W(Δp) dependence are confronted with available W(Δp) data, and the latter is found to agree very well with the data. The results obtained are applicable to homogeneous single-component or multicomponent nucleation from the binodal to the spinodal of the old phase, i.e., in the entire range of the old-phase metastability.
Flow physics of annular and semi-annular fanjet and integration scheme with aircraft wing
Authors: Mehmood Kashif , Shahzad Aamer , Qadri M. N. Mumtaz , Salamat Shuaib , Shams Taimur Ali , Masud Jehanzeb
Published: September 2023

Aerodynamic forces created on the lifting body, like an aircraft wing, can be optimized by modifying the flow field around it. These aerodynamic forces directly influence fuel consumption, thus the economy of flight. Various techniques have been developed and tested on wings for improving aerodynamic efficiency. The present work deals with the integration schemes of fanjets with aircraft wings for the same reason. Fanjets, like bladeless fans, can induce and entrain surrounding air for generation of lift and thrust; however, they are not yet integrated with the wing for modification of aerodynamic forces. In this novel research, the flow physics of the fanjet is explored by varying various geometric parameters. With an increase in the fanjet radius, the mass flow rate decreases, whereas the drag increases. A similar trend was observed for an increase in the jet width. For variation in the angle of attack, the maximum mass flow rate and minimum drag were observed at an angle of 0°. A similar analysis was carried out for semi-annular fanjets. Based on the results, the preferred selection for geometric parameters of annular and semi-annular fanjets was documented for integration with the aircraft wing.
Optimizing the architecture of Behler–Parrinello neural network potentials
Authors: Kývala Lukáš , Dellago Christoph
Published: September 2023

The architecture of neural network potentials is typically optimized at the beginning of the training process and remains unchanged throughout. Here, we investigate the accuracy of Behler–Parrinello neural network potentials for varying training set sizes. Using the QM9 and 3BPA datasets, we show that adjusting the network architecture according to the training set size improves the accuracy significantly. We demonstrate that both an insufficient and an excessive number of fitting parameters can have a detrimental impact on the accuracy of the neural network potential. Furthermore, we investigate the influences of descriptor complexity, neural network depth, and activation function on the model’s performance. We find that for the neural network potentials studied here, two hidden layers yield the best accuracy and that unbounded activation functions outperform bounded ones.
Gauss chains: Quadratic to quintic
Authors: Citrin D. S.
Published: September 2023

Gauss chains are one-dimensional nonperiodic lattices in which lattice sites are located at zj=jnd, with j∈W, n∈N, and d being the underlying lattice constant. They may potentially be realized in semiconductor superlattices or tailored chain molecules. In recent work, we have characterized the electronic delocalized states for the quadratic Gauss chain n=2 obtained using a one-dimensional transfer-matrix approach applied to the Kronig–Penney model. We here extend those results to cases of larger n, illustrating the approach for n=3, 4, and 5. Beginning with the structure factor, we find that the case n=2 has a visually evident structure lacking for n>2, and this structure (or lack thereof) is reflected in the statistics of the structure factor. Turning to the electronic structure, the delocalized-state spectrum for each n is singular-continuous with delocalized states at wavevectors k for all rational multiples rs of πd with r,s∈N coprime in the limit of weak onsite potential parameter λ. Most states, however, become localized at a state-dependent threshold value of |λ|. The case n=2 appears to exhibit delocalized-state spectra that most clearly reveal the hidden symmetry of these systems. Gauss chains with various n, therefore, provide a way (in principle) to realize a class of functions of number-theoretic importance.
Approximating large-basis coupled-cluster theory vibrational frequencies using focal-point approximations
Authors: Nelson Philip M. , Glick Zachary L. , Sherrill C. David
Published: September 2023

The focal-point approximation can be used to estimate a high-accuracy, slow quantum chemistry computation by combining several lower-accuracy, faster computations. We examine the performance of focal-point methods by combining second-order Møller–Plesset perturbation theory (MP2) with coupled-cluster singles, doubles, and perturbative triples [CCSD(T)] for the calculation of harmonic frequencies and that of fundamental frequencies using second-order vibrational perturbation theory (VPT2). In contrast to standard CCSD(T), the focal-point CCSD(T) method approaches the complete basis set (CBS) limit with only triple-ζ basis sets for the coupled-cluster portion of the computation. The predicted harmonic and fundamental frequencies were compared with the experimental values for a set of 20 molecules containing up to six atoms. The focal-point method combining CCSD(T)/aug-cc-pV(T + d)Z with CBS-extrapolated MP2 has mean absolute errors vs experiment of only 7.3 cm−1 for the fundamental frequencies, which are essentially the same as the mean absolute error for CCSD(T) extrapolated to the CBS limit using the aug-cc-pV(Q + d)Z and aug-cc-pV(5 + d)Z basis sets. However, for H2O, the focal-point procedure requires only 3% of the computation time as the extrapolated CCSD(T) result, and the cost savings will grow for larger molecules.
Bubble breakage and aggregation characteristics in a vortex pump under bubble inflow
Authors: He Deng-Hui , Wang Ge , Liu Zheng , Huang Rui
Published: September 2023

The behaviors of bubbles in a vortex pump play a crucial role in its performance when handling gas–liquid flows. However, not much research has been done on the distribution of the gas–liquid phases and the characteristics of bubble breakage and aggregation in vortex pumps. This lack of understanding hinders the improvement of pump performance in gas–liquid flow transport. This study aims to investigate the bubble characteristics in a vortex pump using the population balance model, focusing on the variation of bubble size and the influence of the inlet gas volume fraction (IGVF) on bubble breakage and aggregation. The results show that as the IGVF increases, the gas volume fraction in the impeller becomes larger than that in the bladeless chamber. The majority of bubbles in the impeller are concentrated near the hub, while they also remain in the circulating-flow zone of the bladeless chamber. Under low IGVF conditions, the average diameter of bubbles decreases from the pump inlet to the outlet. The bladeless chamber has a larger average bubble diameter and a higher percentage of large bubbles compared to other parts of the pump. Moreover, the bubble number density at the pump outlet increases with the IGVF, indicating the production of more bubbles, while the increase in IGVF also results in an increase in the percentage of large bubbles. The study also discusses the mechanism of bubble breakage and aggregation in vortex pumps. It suggests that the effective breakage frequency and effective aggregation frequency are responsible for bubble breakage and aggregation in the vortex pump. The gas volume fraction and turbulent dissipation rate are identified as important parameters affecting the effective breakage and aggregation frequency. These findings provide new insights into understanding the characteristics of bubble breakage and aggregation in vortex pumps.
The Brain Balance® programme improves attention and classroom behaviour in students with attentional and developmental challenges in a school setting (El programa Brain Balance® mejora la atención y el comportamiento en el aula de estudiantes con dificultades de atención y de desarrollo en un entorno escolar)
Authors: Jackson Rebecca , Glanz Ryan M.
Published: September 2023

The Brain Balance® (BB) programme has been examined in a centre-based setting, but not yet in a school setting. This pilot study assessed sensorimotor, behavioural and cognitive functioning of students aged 5–15 years with pre-existing developmental and academic challenges who attended three one-hour sessions/week of the BB programme on-site at school ( n = 15). Non-participating students served as controls (CTLs; n = 11). Before the programme, BB participants were more likely than CTLs to achieve low scores on at least two of six Cambridge Brain Sciences (CBS) cognitive tests. After the programme, the number of these participants with low scores decreased, compared with CTLs. Following participation, the BB group also demonstrated diminished primitive reflexes and improvement in scores on the Vanderbilt ADHD Diagnostic Teacher Rating Scale (VADTRS), and higher scores on sensorimotor tasks, compared with CTLs. Finally, BB participants tended to improve test accuracy and reaction times on six CBS cognitive tests (non-significant). These preliminary results show the potential efficacy of the BB programme in a school setting. Future studies will assess the programme in larger student populations.
An asymptotic framework for gravitational scattering
Authors: Compère Geoffrey , Gralla Samuel E , Wei Hongji
Published: September 2023

Asymptotically flat spacetimes have been studied in five separate regions: future/past timelike infinityi±, future/past null infinity, and spatial infinityi0. We formulate assumptions and definitions such that the five infinities share a single Bondi–Metzner–Sachs (BMS) group of asymptotic symmetries and associated charges. We show how individual ingoing/outgoing massive bodies may be ascribed initial/final BMS charges and derive global conservation laws stating that the change in total charge is balanced by the corresponding radiative flux. This framework provides a foundation for the study of asymptotically flat spacetimes containing ingoing and outgoing massive bodies, i.e. for generalized gravitational scattering. Among the new implications are rigorous definitions for quantities like initial/final spin, scattering angle, and impact parameter in multi-body spacetimes, without the use of any preferred background structure.
Strong infiltrative HHC36 antimicrobial peptide/silver nanoparticles-loaded carboxymethyl chitosan/sodium alginate hydrogel for acne vulgaris therapy
Authors: Liu Hongju , Zhan Jiezhao , Lin Ruibin , Yin Ying , Ren Li
Published: September 2023

Acne is a common chronic skin inflammatory disease closely related to Cutibacterium acnes (C. acnes), which affects the life quality of patients worldwide, especially adolescents and young adults. However, the physical barrier of the skin makes drugs difficult to infiltrate effectively into infected site, causing acne hard to cure and easy to recur. Herein, we developed an antibacterial skin dressing with strong infiltration of antibacterial agents which can co-delivery small-molecular antimicrobial agents through stratum corneum deeply into dermis, achieving high antimicrobial efficacy. The antibacterial dressings were constructed with carboxymethyl chitosan/sodium alginate (CMCS/SA) hydrogel loading with HHC36 (an antimicrobial peptide) and silver nanoparticles (AgNPs) conjugates (Ag–H2/CMCS/SA hydrogel). The released Ag–H2 from Ag–H2/CMCS/SA hydrogel can early infiltrate into dermis, co-delivery HHC36 and AgNPs due to the infiltration and targeting of HHC36, presenting the superior antibacterial effect compared to HHC36 or AgNPs alone and killing 100% C. acnes and 100% Staphylococcus epidermidis (S. epidermidis) at a very low concentration of Ag–H2 (15 μg ml−1 A g with 7.1 μg ml−1 HHC36). Meanwhile, Ag–H2/CMCS/SA hydrogel was biocompatible due to the natural polysaccharides carboxymethyl chitosan and sodium alginate. The HaCaT cells spread well in Ag–H2/CMCS/SA hydrogel. These results indicate that the co-delivery small-molecular antimicrobial agents is a promising strategy and Ag–H2/CMCS/SA hydrogel has a great potential in the therapy of acne.
Comparison Between TeV and Non-TeV Fermi-detected BL Lacertae Objects
Authors: Liang Jingchao , Zeng Xiangtao , Chen Guohai , Ye Xuhong , Zhu Jingtian , Xiao Hubing , Pei Zhiyuan , Du Guangjie , Ying Gao , Fan Junhui
Published: September 2023

In this paper, we compiled a sample of 410 Fermi-detected BL Lacs, including 42 TeV-detected BL Lacs (TBLs) and 368 non-TeV-detected BL Lacs (non-TBLs) with corresponding mid-infrared (mid-IR), TeV and Fermi γ-ray data, and calculated some important parameters including monochromatic luminosities (mid-IR, GeV and TeV bands) and mid-IR spectral indices. Based on those parameters, we discussed the relationship between the mid-IR and the TeV bands and that between the mid-IR and the GeV bands. Main conclusions are drawn as follows: (1) In the color–color and color–magnitude diagrams, our sample forms a WISE-Gamma Strip in the [3.4]–[4.6]–[12] μm color–color diagram, and TBLs occupy the brighter region than the non-TBLs for the similar color-index in the color-magnititue diagram; (2) The mid-IR luminosity of the TBLs is on average higher than that of non-TBLs, while the average mid-IR spectral index of TBLs is smaller than the non-TBLs, suggesting that TBLs are brighter and hold a more flat spectrum than do the non-TBLs in the mid-IR band. Besides, HBLs have a more flat mid-IR spectrum than LBLs and IBLs; (3) The mid-IR luminosity is positively correlated with the GeV luminosity and the intrinsic TeV luminosity. A positive correlation exists between the mid-IR spectral index and the observed TeV spectral index, which is consistent with the expectations of the synchrotron self-Compton mechanism. We suggest that the HBLs with extreme relativistic electrons might scatter the mid-IR photons up to the TeV band.
Gait recognition with covariate separation based on adversarial learning
Authors: Zhu Yongsheng , Hu Weijun , Zhou Hongming
Published: September 2023

In response to the poor recognition accuracy caused by viewpoint changes and wearing changes in gait recognition problems, a viewpoint classifier and a wearing classifier are proposed to be connected after the feature extractor. The parameters of the feature extractor are updated using the gradient reversal mechanism so that its function is opposite to that of the two classifiers, thereby separating the viewpoint information, wearing information at the feature extraction level, and reducing the impact of these two most common factors on gait recognition. Comparative experiments on the CASIA-B dataset show that under BG and CL conditions, our model has improved by an average of 2.1% and 1.9% in cross-viewpoint accuracy compared to the baseline model. Our model is more robust under complex walking conditions.
Barcode positioning method based on line detection under non-uniform illumination
Authors: Sang Mingxiu
Published: September 2023

The positioning problem of the barcode is easily affected by factors such as uneven illumination and complex background. Based on the EDLines line detection algorithm, a positioning algorithm that can deal with the barcode positioning problem under non-uniform lighting conditions is proposed. First, the EDLines algorithm is used to detect the straight-line segment of the image, and the midpoint coordinates of all line segments are extracted. Since the midpoint coordinates near the barcode are relatively densely distributed, the density-based HDBSCAN point clustering algorithm is used for all midpoint coordinates for density clustering. Then a filtering strategy based on the consistency of line segment direction is proposed to preliminarily filter the clustering results, and one or more point clustering results that may belong to the barcode area are obtained. Then the RANSAC algorithm is used to perform line fitting on the point clustering results. The accuracy of the straight-line fitting results is judged by direction consistency screening, and the intersection of the fitted straight line and the straight-line segment to which the centroid belongs is calculated for the results that meet the expectations, and the width of the barcode area is obtained. Finally, the straight-line segment obtained by screening is calculated. The average length and the height of the barcode area are got, to accurately locate the barcode position. Compared with the previous algorithms on the public barcode dataset and the self-made barcode dataset, the algorithm has good positioning accuracy and running speed.
A Re-detection Target Tracking Framework after Loss for Unmanned Aerial Vehicle
Authors: Chao Chuang , Wu Jun , Zhang Yuxin , Chen Honglin
Published: September 2023

Currently, the target tracking algorithm based on discriminative correlation filter (DCF) and deep learning (DL) plays an increasingly important role in UAV (unmanned aerial vehicle). However, existing algorithms have limitations such as limited search region, difficulty in re-capturing targets when tracking is lost, and high computational complexity, which makes them difficult to apply to the UAV platform. In this paper, a target re-detection tracking algorithm (RDT) after tracking loss is designed for mobile platforms. RDT uses DCF in simple scenes to track targets and establish a target model between different frames. To ensure the algorithm when tracking is lost due to occlusion or moving out of view, an efficient switching criterion is designed to indirectly invoke the detection algorithm to re-capture the target and guide online learning of DCF. And the experiment results on the OTB benchmark show that RDT can re-capture the target after tracking is lost, and the speed of operation on the CPU is 85fps.
Spatial-temporal regularized UAV correlation filter based on adaptive filter template
Authors: Chai Jinchuan , Ding Jialiang
Published: September 2023

Due to its quick computation, the correlation filter (CF) is frequently employed in object-tracking activities. The occlusion and deformation of the tracking object during the CF tracking process will pollute the filter, which will cause the filter’s performance to degrade. This is especially obvious in unmanned aerial vehicle (UAV) tracking and increased interfered sequences will further aggravate the problem. In response to this problem, we use ARCF as the baseline and add a spatial-temporal regularization term based on the adaptive template. We also introduce a historical filter template to generate a more global adaptive template. The experimental results illustrate that our tracker has the most sophisticated capabilities compared to the other 8 SOTA trackers on the DTB70 benchmark.
Research on subpixel partition correction method for simulating star position in star simulation system
Authors: Wu Linghao , Wang Jiaan , Jia Wentao , Zhang Jian , Sun Jingrui
Published: September 2023

The accuracy of star position simulation in star simulation systems is a key factor affecting the accuracy of ground calibration experiments for star sensors. In order to solve the problem that the current simulation star position accuracy is restricted by the size of its constituent elements, In this paper, the mathematical model for simulating the star position correction and the gray distribution of the constituent elements is derived, and the functional representation of the azimuth and longitude correction, elevation and latitude correction of the simulated star position is established. Exploring the distribution law of star position simulation error and establishing a corrected sub interval based on it, achieving sub pixel level star position simulation accuracy. The experimental results show that after using the method proposed in this article, the accuracy of star position simulation has been improved by 1.74 times.
The altered hippocampal functional connectivity and serum brain-derived neurotrophic factor level predict cognitive decline in patients with knee osteoarthritis
Authors: Liu Jiao , Tao Jing , Cai Guiyan , Chen Jie , Zhao Lei , Wang Yajun , Xu Shurui , Chen Ruilin , Hu Li , Cao Jin , Chen Lidian , Tu Yiheng
Published: September 2023

Patients with knee osteoarthritis (KOA) often suffer from cognitive decline and increased dementia risk, but the neurobiological mechanisms remain unclear. In this study, we evaluated cognitive performance and collected brain magnetic resonance imaging (MRI) data and blood samples from cognitively normal KOA patients at baseline sessions and reevaluated their cognition after 5 years. We also collected MRI data from matched healthy controls. Results showed that KOA patients exhibited dysregulated functional connectivities between the hippocampus and thalamus/superior frontal gyrus compared with healthy controls. The altered hippocampal functional connectivities were associated with serum brain-derived neurotrophic factor (BDNF) levels and spatial expression of genes enriched in synaptic plasticity. The hippocampus–thalamus functional connectivity was significantly correlated with patients’ memory scores. Moreover, the baseline hippocampus–thalamus functional connectivity and BDNF levels significantly predicted the development of cognitive decline in KOA patients in the follow-up session. Our findings provide insight into the neurobiological underpinnings of KOA and cognitive decline.
Patient perspectives on same-day discharge following catheter ablation for atrial fibrillation: results from a patient survey as part of the monocentric FAST AFA trial
Authors: König Sebastian , Wohlrab Lisa , Leiner Johannes , Pellissier Vincent , Nitsche Anne , Darma Angeliki , Hilbert Sebastian , Nedios Sotirios , Seewöster Timm , Dinov Borislav , Hindricks Gerhard , Bollmann Andreas
Published: September 2023

Aims

Same-day discharge (SDD) following catheter ablation (CA) of atrial fibrillation (AF) was already introduced in selected facilities in Europe, but a widespread implementation has not yet succeeded. Data on patients’ perspectives are lacking. Therefore, we conducted a survey to address patients’ beliefs towards SDD and identify variables that are associated with their evaluation.

Methods and results

As part of the prospective, monocentric FAST AFA trial, patients aged ≥20 years undergoing left atrial CA for AF were asked to participate in the survey consisting of a study-specific questionnaire, the AF knowledge scale, and pre-defined patient-reported outcome measures. The study cohort was stratified based on SDD willingness, and a logistic regression analysis was used to identify predictors for patients’ valuation. Between 26 July 2021 and 01 July 2022, 256 of 376 screened patients consented to study participation of whom 248 (mean age 61.8 years, 33.9% female) completed the SDD survey. Of them, 50.0% were willing to have SDD concepts integrated into their clinical course with increased patient comfort (27.5%), shorter waiting times (14.6%), and a cost-efficient treatment (14.0%) being imaginable benefits. In contrast, expressed concerns included uncertainties with occurring complaints (50.6%), the insufficient recognition (47.8%), and treatment (48.9%) of complications. European Heart Rhythm Association class at baseline and inpatient treatments within the preceding year were predictors for SDD willingness whereas comorbidity burden or AF knowledge were not.

Conclusion

We provide a detailed survey expressing patients’ beliefs towards SDD following left atrial CA. Our findings may facilitate adequate patient selection to improve the future implementation of SDD programs in suitable cohorts.
Methodologies for bacterial ribonuclease characterization using RNA-seq
Authors: Broglia Laura , Le Rhun Anaïs , Charpentier Emmanuelle
Published: September 2023

Bacteria adjust gene expression at the post-transcriptional level through an intricate network of small regulatory RNAs and RNA-binding proteins, including ribonucleases (RNases). RNases play an essential role in RNA metabolism, regulating RNA stability, decay, and activation. These enzymes exhibit species-specific effects on gene expression, bacterial physiology, and different strategies of target recognition. Recent advances in high-throughput RNA sequencing (RNA-seq) approaches have provided a better understanding of the roles and modes of action of bacterial RNases. Global studies aiming to identify direct targets of RNases have highlighted the diversity of RNase activity and RNA-based mechanisms of gene expression regulation. Here, we review recent RNA-seq approaches used to study bacterial RNases, with a focus on the methods for identifying direct RNase targets.
Seismic image of the mantle transition zone beneath northeastern China: evidence for stagnant Pacific subducting slab, lithospheric delamination and mantle upwelling
Authors: Tang Zheng , Julià Jordi , Mooney Walter D , Mai Paul Martin , Yu Huazhi , Wu Yanqiang
Published: September 2023

We provide a comprehensive image of the mantle transition zone (MTZ) beneath northeastern China by performing Variable Bin Radius Stacking of receiver functions. A massive seismic data set consisting of over 133 000 receiver functions recorded by 1208 broad-band stations is processed. Our results reveal fine-scale topography on the 410- and 660-km discontinuities defining the upper and lower bounds of the MTZ, lateral variations in the MTZ thickness and slab interfaces within the MTZ. In particular, unambiguous images of the slab interfaces provide direct evidence for the presence of the stagnant Pacific subducting slab below the eastern portion of the study area. A widespread deepening of the 410-km discontinuity is consistent with a hot and wet low-velocity upper mantle resulting from dehydration of the stagnant slab. Prominent depressions are evident in the depth to the 660-km discontinuity, with a thickened MTZ associated with the cold stagnating slab. Localized uplifts of the 660-km discontinuity are possibly caused by partial melt under the slab. These features attest to the influence of the Pacific plate on the MTZ. Additionally, a pronounced upwarp on the 660-km interface with a thin MTZ agrees with a previously hypothesized mantle upwelling through a slab window, possibly triggered by the sinking of the stagnant slab. Moreover, the western part of the study region is characterized by alternating ups and downs of the 410-km interface, while the topography of the 660-km discontinuity is relatively flat. We propose the western region is dominated by foundering of delaminated lithospheric blocks that induced upward mantle return flows upon entrance into the MTZ.
Impact of gastro-jejunostomy tube in lung transplant patients: a propensity-matched analysis
Authors: Furukawa Masashi , Chan Ernest G , Ryan John P , Coster Jenalee N , Sanchez Pablo G
Published: September 2023

OBJECTIVES

During the postoperative phase of lung transplantation, the surgical creation of a gastro-jejunostomy (GJ) may be deemed necessary for patients with severe oesophageal dysmotility, prolonged oral intake difficulties stemming from use of a ventilator or marked malnutrition. We explored the effects of postoperative GJ tube on survival and bronchiolitis obliterans syndrome in lung transplant recipients.

METHODS

We retrospectively reviewed all lung transplants performed at our institution between 2011 and 2022. Propensity score matching was performed to match patients who required a GJ tube with control patients on a 1:1 ratio. The preoperative, operative and postoperative outcomes of the patients were evaluated.

RESULTS

After propensity score matching, 193 patients with GJ were compared to 193 patients without GJ. Patients with GJ had significantly higher rates of delayed chest closure (P = 0.007), and postoperative dialysis (P = 0.016), longer intensive care unit stays (P < 0.001), longer ventilator duration (P < 0.001), higher rates of pneumonia (P = 0.035) and higher rates of being treated for acute cellular rejection within 1 year of transplant (P = 0.008). Overall survival and freedom from bronchiolitis obliterans syndrome were not found to be significantly different between the matched groups (P = 0.09 and P = 0.3).

CONCLUSIONS

GJ tube placement during the postoperative phase of lung transplantation did not compromise patient survival or freedom from bronchiolitis obliterans syndrome although the results reflect more difficult and complicated cases. This study indicates that the GJ tube may be a useful option for enteral feeding.
Sets of Non-Lyapunov Behaviour for Scalar and Matrix Schrödinger Cocycles
Authors: Goldsheid Ilya , Sodin Sasha
Published: September 2023

We discuss the growth of the singular values of symplectic transfer matrices associated with ergodic discrete Schrödinger operators in one dimension, with scalar and matrix-valued potentials. While for an individual value of the spectral parameter the rate of exponential growth is almost surely governed by the Lyapunov exponents, this is not, in general, true simultaneously for all the values of the parameter. The structure of the exceptional sets is interesting in its own right, and is also of importance in the spectral analysis of the operators. We present new results along with amplifications and generalisations of several older ones, and also list a few open questions.

Here are two sample results. On the negative side, for any square-summable sequence $p_{n}$ there is a residual set of energies in the spectrum on which the middle singular value (the $W$-th out of $2W$) grows no faster than $p_{n}^{-1}$. On the positive side, for a large class of cocycles including the i.i.d. ones, the set of energies at which the growth of the singular values is not as given by the Lyapunov exponents has zero Hausdorff measure with respect to any gauge function $\rho (t)$ such that $\rho (t)/t$ is integrable at zero.

The employed arguments from the theory of subharmonic functions also yield a generalisation of the Thouless formula, possibly of independent interest: for each $k$, the average of the first $k$ Lyapunov exponents is the logarithmic potential of a probability measure.
Modelling supra-classical logic in a Boltzmann neural network: III adaptation
Authors: Blanchette Glenn , Robins Anthony
Published: September 2023

The field of belief revision in logic is still in evolution and holds a variety of disparate approaches; a consequence of theoretical conjecture. As a probabilistic model of supra-classical, non-monotonic (SCNM) logic, the Boltzmann machine, offers an experimental gateway into the field. How does the Boltzmann network adapt to new information?

Catastrophic forgetting is the default response to retraining in any neural network. We have moderated this irrational non-monotonicity by alterations in the Boltzmann learning algorithm. The spectrum of experimental belief change is limited by the availability of ‘new’ information, a pragmatic realization co-related to the property of Rational Monotonicity in the domain of SCNM logic. Recognizing this upper boundary of defeasible belief simplifies the task of experimentally exploring machine adaptation.

A minority of belief revisions involve new, but unsurprising information, that is at least partially consistent with the previous learned beliefs. In these circumstances, the Boltzmann network incrementally adjusts the priority of model state exemplars in accordance with preference; the traditional approach in SCNM logic. However, in the majority of situations the new information will be surprisingly inconsistent with the previous beliefs. In these circumstances, the pre-order on model states stratified by preference, will not have sufficient granularity to represent the conflicting requirements of ranking based on compositional atomic typicality. This novel experimental finding has not previously been considered in the logical conjecture on Belief Revision.
Fundamental parameters of two O9-type giant stars: the (former) spectral classification standard HD 93249 A and ALS 12502 A
Authors: Ansín T , Gamen R , Morrell N I , Barbá R H , Maíz Apellániz J , Arias J I , Simón-Díaz S , Holgado G
Published: September 2023

The evolution of massive stars is not completely understood. Several phenomena affect their birth, life, and death, multiplicity being one of them. In this context, the OWN and MONOS projects are systematically observing O- and WN-type stars whose multiplicity status is unknown. Their major goal considers the necessity of determining absolute parameters of massive stars. We have collected spectra of HD 93249 A and ALS 12502 A aiming at characterizing their binary nature. For both stars, we analysed high-resolution spectra and combined them with Transiting Exoplanet Survey Satellite (TESS) observations to be compared with binary models constructed by means of the phoebe code. We discovered that the radial velocity of HD 93249 A varies with a period of 2.97968 ± 0.00001 d and that the system presents ellipsoidal light variations. We disentangled the composite spectra and classified its components as O9 III and B1.5 III, respectively. Confirmed as a spectroscopic binary, HD 93249 A can no longer be used as spectral classification standard. ALS 12502 A turned out to be a detached eclipsing binary in the TESS and Gaia data. These results enable us to determine absolute parameters for each component in the system.
Star formation and chemical enrichment in protoclusters
Authors: Fukushima Keita , Nagamine Kentaro , Shimizu Ikkoh
Published: September 2023

We examine star formation and chemical enrichment in protoclusters (PCs) using cosmological zoom-in hydrodynamic simulations. We find that the total star formation rate (SFR) in all PC ($\gt 10^{14.4}\, h^{-1}$ M⊙) reaches $\gt 10^4\, \mathrm{M}_\odot \mathrm{yr}^{-1}$ at z = 3, equivalent to the observed PCs. The SFR in the Core region accounts for about 30  per cent of the total star formation in the PC at z ≳ 1, suggesting the importance of the outer regions to reveal the evolution of galaxy clusters. We find that the total SFR of PC is dominated by galaxies with stellar masses $10^{10}\, \le \, (\mathrm{M}_\star /{{\rm M}_{\odot }})\, \le \, 10^{11}$, while more massive galaxies dominate the SFR in the Core. For the chemical abundance evolution, we find that the higher-density region has a higher metallicity and faster evolution. We show that the [O/Fe] versus [Fe/H] relation turns down in the Core at z = 3.4 due to the enrichment of Fe by Type Ia supernovae. We find no environmental effects for the mass–metallicity relations (MZR) or log (N/O) versus 12 + log (O/H) for galaxies. We find that the chemical enrichment in galaxy clusters proceeds faster in the high-redshift universe (z > 1). Our work will benefit future tomographic observations, particularly using PCs as unique probes of accelerated structure formation and evolution in high-density regions of the universe.