bluuebunny/crossref_metadata_2025 huggingface dataset:
Cryogen free spin polarized scanning tunneling microscopy and magnetic exchange force microscopy with extremely low noise
Authors: Huang Haiming , Shuai Mingming , Yang Yulong , Song Rui , Liao Yanghui , Yin Lifeng , Shen Jian
Published: July 2022

Spin polarized scanning tunneling microscopy (SP-STM) and magnetic exchange force microscopy (MExFM) are powerful tools to characterize spin structure at the atomic scale. For low temperature measurements, liquid helium cooling is commonly used, which has the advantage of generating low noise but has the disadvantage of having difficulties in carrying out measurements with long durations at low temperatures and measurements with a wide temperature range. The situation is just reversed for cryogen-free STM, where the mechanical vibration of the refrigerator becomes a major challenge. In this work, we have successfully built a cryogen-free system with both SP-STM and MExFM capabilities, which can be operated under a 9 T magnetic field provided by a cryogen-free superconducting magnet and in a wide temperature range between 1.4 and 300 K. With the help of our specially designed vibration isolation system, the noise is reduced to an extremely low level of 0.7 pm. The Fe/Ir(111) magnetic skyrmion lattice is used to demonstrate the technical novelties of our cryogen-free system.
Imaging-based feedback cooling of a levitated nanoparticle
Authors: Minowa Y. , Kato K. , Ueno S. , Penny T. W. , Pontin A. , Ashida M. , Barker P. F.
Published: July 2022

Imaging-based detection of the motion of levitated nanoparticles complements a widely used interferometric detection method, providing a precise and robust way to estimate the position of the particle. Here, we demonstrate a camera-based feedback cooling scheme for a charged nanoparticle levitated in a linear Paul trap. The nanoparticle levitated in vacuum was imaged using a complementary metal-oxide semiconductor (CMOS) camera system. The images were processed in real-time with a microcontroller integrated with a CMOS image sensor. The phase-delayed position signal was fed back to one of the trap electrodes, resulting in cooling by velocity damping. Our study provides a simple and versatile approach applicable for the control of low-frequency mechanical oscillators.
Mn environment in doped SrTiO3 revealed by first-principles calculation of hyperfine splittings
Authors: Repa Gil M. , Fredin Lisa A.
Published: July 2022

In order to take advantage of the strong correlation between geometric changes and electronic properties, better understanding of the structure and properties of perovskites doped with paramagnetic transition metal ions is required. Computational characterization of these dopants and calculated hyperfine values provide a guide that can ultimately aid in the interpretation of experimentally obtained electron paramagnetic resonance (EPR) spectra. In this study, we perform ab initio calculation of the hyperfine splitting parameter for Sr-substituted Mn2+ in SrTiO3 in various geometries in order to assign experimentally reported EPR peaks to exact dopant structures. Additionally, we calculate the hyperfine parameters for Mn4+ and Mn2+∕4+ with adjacent oxygen vacancy, which remain to be assigned peaks in experimental EPR spectra. Calculation of Ti-substituted Mn is largely hindered by the highly correlated electronic structure; however, it is shown that reasonable hyperfine values for Ti-site defects can be obtained by tuning functional parameters. Overall, this study demonstrates that calculating the hyperfine splitting for a transition metal dopant in a complex oxide is feasible and can provide a fingerprint for different geometries in equivalently defected systems.
Incoherent phonon transport dominates heat conduction across van der Waals superlattices
Authors: Zhao Lu , Zhang Lijuan , Song Houfu , Du Hongda , Wu Junqiao , Kang Feiyu , Sun Bo
Published: July 2022

Heat conduction mechanisms in superlattices could be different across different types of interfaces. Van der Waals superlattices are structures physically assembled through weak van der Waals interactions by design and may host properties beyond the traditional superlattices limited by lattice matching and processing compatibility, offering a different type of interface. In this work, natural van der Waals (SnS)1.17(NbS2)n superlattices are synthesized, and their thermal conductivities are measured by time-domain thermoreflectance as a function of interface density. Our results show that heat conduction of (SnS)1.17(NbS2)n superlattices is dominated by interface scattering when the coherent length of phonons is larger than the superlattice period, indicating that incoherent phonon transport dominates through-plane heat conduction in van der Waals superlattices even when the period is atomically thin and abrupt, in contrast to conventional superlattices. Our findings provide valuable insights into the understanding of the thermal behavior of van der Waals superlattices and devise approaches for effective thermal management of superlattices depending on the distinct types of interfaces.
A nanogapped hysteresis-free field-effect transistor
Authors: Tang Jiachen , Liu Luhao , Shao Yinjiang , Wang Xinran , Shi Yi , Li Songlin
Published: July 2022

We propose a semi-suspended device structure and construct nanogapped, hysteresis-free field-effect transistors (FETs), based on the van der Waals stacking technique. The structure, which features a semi-suspended channel above a submicrometer-long wedge-like nanogap, is fulfilled by transferring ultraclean boron nitride-supported MoS2 channels directly onto dielectric-spaced vertical source/drain stacks. Electronic characterization and analyses reveal a high overall device quality, including ultraclean channel interfaces, negligible electrical scanning hysteresis, and Ohmic contacts in the structures. The unique hollow FET structure holds the potential for exploiting reliable electronics as well as nanofluid and pressure sensors.
Interferometry of quantum revivals
Authors: Tarrant J. , Khokhlova M. , Averbukh V.
Published: July 2022

It has recently been shown that an interferometric approach can be used to obtain Auger lifetimes in molecules in certain point groups. Here, we extend this concept to those molecular states for which Auger decay is energetically forbidden and which exhibit initial quasi-exponential decay followed by quantum revivals. We demonstrate that this allows us to extract the quasi-exponential decay rate and the revival timescale. We solve analytically a model containing a state coupled to the idealized Bixon–Jortner quasicontinuum, and we obtain an interferometric signature of revival, which can be easily generalized to realistic systems. Moreover, we analyze how this revival signature is influenced by the system parameters, and we suggest optimal conditions for its observation. We, therefore, show that our new approach allows population revivals of a molecular state to be detected interferometrically.
Strain effect on adsorption and reactions of AHx (A = C, N, O, x ≤ 3) on In2O3(110), TiO2(110), and ZrO2(101) surfaces
Authors: Lu Huili , Chen Zhao-Xu
Published: July 2022

More and more attention has been paid to strain-based regulation of catalytic activity. To guide regulation of catalytic performance via strain engineering, adsorption and reactions of AHx (A = C, N, O, x ≤ 3) were investigated on uniformly strained In2O3 (110), rutile TiO2 (110), and tetragonal ZrO2 (101) from −2% to 4%. The results show that adsorption energies vary linearly with strain; expansive strain enhances the adsorption of most adsorbates. Unlike the adsorbate scaling relations that are central atom dependent, the adsorbate scaling relations on strained surfaces are central atom independent. C–H/O–H bonds are elongated/shortened with expansive strain, and adsorption energies of CHx generally change more than those of OHx and NHx, which can be rationalized with effective medium theory and pertinent bond energies. Thermodynamically, In2O3(110)/ZrO2(101) is the most active/inactive. The estimated variation of rate constants at 300 K from 0% to 2% strain based on the Brønsted–Evans–Polanyi relationship demonstrates great strain regulation potential of catalytic performance on these oxide surfaces. Finally, it is demonstrated that strain tends to facilitate the reactions whose sum of the stoichiometric number is positive, which can be used as a rule to guide strain engineering for heterogeneous catalysis.
Flow of a shallow film over a moving surface
Authors: Liu Xiaohe , Green Sheldon , Stoeber Boris , Balmforth Neil J.
Published: July 2022

The von-Karman–Pohlhausen averaging technique is employed to build a reduced model for the flow of a shallow film from a sluice gate or impacting jet over a moving surface. The viscous drag exerted on the film by the moving wall acts to arrest flow counter to the direction of the wall's motion, and force an adjustment toward the wall speed. For a (normally) impacting jet, this results in a range of wall speeds for which a steady state is reached in which all the fluid is eventually recirculated to flow along the wall, with a distinctive “heel” forming upstream of the impact region. For wall speeds below this range, the flow counter to the wall cannot be arrested, and unsteady states result. For wall speeds above this range, a different steady state emerges in which fluid is immediately diverted through and downstream of the impact region, eliminating any heel. The steady, heeled flow states predicted by the reduced model are in qualitative agreement with numerical simulations of the full two-dimensional problem.
Theoretical understanding on all-solid frustrated Lewis pair sites of C2N anchored by single metal atom
Authors: Zhu Yijia , Jian Changping , Xue Ruifang , Zhang Wei , Guo Rou , Gao Yijing , Chen De-Li , Zhang Fumin , Zhu Weidong , Wang Fang-Fang
Published: July 2022

The design of all-solid heterogeneous catalysts with frustrated Lewis pairs (FLPs) has attracted much attention recently because of their appealing low dissociation energy for H2 molecules due to which a promotion of hydrogenation reaction is expected. The sterically encumbered Lewis acid (metal site) and base (nitrogen site) in the cavity of single transition metal atom-doped M/C2N sheets make them potential candidates for the design of catalysts with FLPs, while a comprehensive understanding of their intrinsic property and reactivity is still lacking. Calculations show that the complete dissociation of the H2 molecule into two H* states at the N sites requires two steps: heterolytic cleavage of the H2 molecule and the transfer of H* from the metal site to the N site, which are strongly related to the acidity of the metal site. Ni/C2N and Pd/C2N, which outperform the other eight transition metal atom (M) anchored M/C2N candidates, possess low energy barriers for the complete dissociation of H2 molecules, with values of only 0.30 and 0.20 eV, respectively. Furthermore, both Ni/C2N and Pd/C2N catalysts can achieve semi-hydrogenation of C2H2 into C2H4, with overall barriers of 0.81 and 0.75 eV, respectively, which are lower than those reported for many other catalysts. It is speculated that M/C2N catalysts with intrinsic FLPs may also find applications in other important hydrogenation reactions.
Highly sensitive and broadband photodetectors based on WSe2/MoS2 heterostructures with van der Waals contact electrodes
Authors: Xiao Haodong , Lin Lin , Zhu Jia , Guo Junxiong , Ke Yizhen , Mao Linna , Gong Tianxun , Cheng Huanyu , Huang Wen , Zhang Xiaosheng
Published: July 2022

A nanoscale photodetector is a crucial part of intelligent imaging and wireless communication devices. Building van der Waals (vdWs) heterostructures based on two-dimensional transition metal dichalcogenides is thought to be a smart approach for achieving nanoscale photodetectors. However, the pinning effect induced by surface states, defects, and metal-induced gap states during the fabrication process of vdWs heterostructures and contacting electrodes leads to a large Schottky barrier and consequently limits the photoresponse of vdWs heterostructures. In this study, a photodetector based on the WSe2/MoS2 heterostructure with graphene (Gr)/indium tin oxide (ITO) hybrid electrodes has been fabricated. The vdWs contacts established between the exfoliated graphene layers and WSe2/MoS2 heterostructure are able to get rid of lattice damages caused by atom bombardment during the deposition of metal electrodes. In addition, the reduced Schottky barrier at graphene/heterostructure interfaces facilitates the transport of carriers. Experimental results show that the photodetector based on WSe2/MoS2 heterostructures with Gr/ITO hybrid electrodes exhibits a high responsivity of up to 1236.5 A W−1, a detectivity of up to 1.23 × 1013 Jones, and a fast response of 270/130 μs to light from the ultraviolet to near-infrared range.
Estimated cloud-top entrainment index explains positive low-cloud-cover feedback
Authors: Koshiro Tsuyoshi , Kawai Hideaki , Noda Akira T.
Published: July 2022

How subtropical marine low cloud cover (LCC) will respond to global warming is a major source of uncertainty in future climate change. Although the estimated inversion strength (EIS) is a good predictive index of LCC, it has a serious limitation when applied to evaluate LCC changes due to warming: The LCC decreases despite increases in EIS in future climate simulations of global climate models (GCMs). In this work, using state-of-the-art GCMs, we show that the recently proposed estimated cloud-top entrainment index (ECTEI) decreases consistently with LCC in warmer sea surface temperature (SST) climates. For the patterned SST warming predicted by coupled GCMs, ECTEI can constrain the subtropical marine LCC feedback to –0.41 ± 0.28% K
−1
(90% CI), implying virtually certain positive feedback. ECTEI physically explains the heuristic model for LCC changes based on a linear combination of EIS and SST changes in previous studies in terms of cloud-top entrainment processes.
Methanol biotransformation toward high-level production of fatty acid derivatives by engineering the industrial yeast
Pichia pastoris
Authors: Cai Peng , Wu Xiaoyan , Deng Jun , Gao Linhui , Shen Yiwei , Yao Lun , Zhou Yongjin J.
Published: July 2022

Methanol-based biorefinery is a promising strategy to achieve carbon neutrality goals by linking CO
2
capture and solar energy storage. As a typical methylotroph,
Pichia pastoris
shows great potential in methanol biotransformation. However, challenges still remain in engineering methanol metabolism for chemical overproduction. Here, we present the global rewiring of the central metabolism for efficient production of free fatty acids (FFAs; 23.4 g/L) from methanol, with an enhanced supply of precursors and cofactors, as well as decreased accumulation of formaldehyde. Finally, metabolic transforming of the fatty acid cell factory enabled overproduction of fatty alcohols (2.0 g/L) from methanol. This study demonstrated that global metabolic rewiring released the great potential of
P. pastoris
for methanol biotransformation toward chemical overproduction.
Id3 expression identifies CD4
+
memory Th1 cells
Authors: Shaw Laura A. , Deng Tianda Z. , Omilusik Kyla D. , Takehara Kennidy K. , Nguyen Quynh P. , Goldrath Ananda W.
Published: July 2022

Memory CD4
+
T cells play a pivotal role in mediating long-term protective immunity, positioning them as an important target in vaccine development. However, multiple functionally distinct helper CD4
+
T-cell subsets can arise in response to a single invading pathogen, complicating the identification of rare populations of memory precursor cells during the effector phase of infection and memory CD4
+
T cells following pathogen clearance and the contraction phase of infection. Furthermore, current literature remains unclear regarding whether a single CD4
+
memory T-cell lineage gives rise to secondary CD4
+
T helper subsets or if there are unique memory precursor cells within each helper lineage. A majority of T follicular helper (Tfh) cells, which have established memory potential, express Id3, an inhibitor of E protein transcription factors, following acute viral infection. We show that expression of Id3 definitively identified a subset of cells within both the CD4
+
Tfh and T helper 1 (Th1) lineages at memory time points that exhibited memory potential, with the capacity for significant re-expansion in response to secondary infection. Notably, we demonstrate that a subset of Th1 cells that survive into the memory phase were marked by Id3 expression and possessed the potential for enhanced expansion and generation of both Th1 and Tfh secondary effector cell populations in a secondary response to pathogen. Additionally, these cells exhibited enrichment of key molecules associated with memory potential when compared with Id3
lo
Th1 cells. Therefore, we propose that Id3 expression serves as an important marker to indicate multipotent potential in memory CD4
+
T cells.
YouTube
Authors: Pelttari Sanna
Published: July 2022

This case study discusses audiences’ emotional reactions and convergent alignment in YouTube comment threads observed on four videos of Spanish YouTubers with affective narratives on sensitive topics. The analysis reveals that most single-comment threads are generally positive and that utterances are fairly equally divided in their focus on YouTubers or narratives. The act of taking a stance follow consists of a versatile process in which the convergent alignment or agreement with the YouTubers’ stance lead occurs not just by positively evaluating YouTubers or the story, but also by revealing something highly private concerning the stance topic. The four affective narratives evoke not only compliments, but also the convergent alignment the YouTubers presumably seek with their stories.
Evaluating multiword unit word lists for academic purposes
Authors: Nguyen Thi My Hang , Coxhead Averil
Published: July 2022

Word lists play a critical role in English for Academic Purposes (EAP) teaching and learning, and recent
developments include lists of academic collocations (e.g., vast majority, ultimate goal). There is however still
a gap in evaluating lists focusing on a similar group of lexis. This paper evaluates two lists of academic collocations by Ackermann and Chen (2013) and Lei and Liu
(2018) using three different methods: applying an evaluation framework adapted from Nation (2016), comparing the lexical constituents, and analysing the lexical coverage. The evaluation results give
implications for EAP teachers to select the list that best suits their needs. By modelling the practice of evaluating word lists,
this study highlights the importance of this work and encourages similar attempts in wordlist development studies.
Compressive behaviour and energy absorption of functionally graded composite foams
Authors: Wang Xiaolong , Yang Xudong , Cheng Ying
Published: July 2022

Based on layered structure, the functionally graded aluminium foams have unique energy absorption behaviour under different conditions. In this work, the functionally graded Al matrix composite foams (FG-AMCFs), which contained the layer of Al foam and the layer of carbon nanotubes reinforced Al composite foams, were successfully prepared. The compressive properties and energy absorption response of FG-AMCFs were studied under the quasi-static compression and drop-weight tests. The results show that the content of CNTs (less than 3 wt-%) has little effect on the mechanical properties of FG-AMCFs under quasi-static compression. While, the load of FG-ACMFs remains relatively stable under drop-weight impact, which indicates that FG-ACMFs is an excellent impact protection material. The deformation of FG-AMCFs starts from the weakest layer.
Anti-fraud measures in Western Africa and commentary on research findings across the three regions analysed
Authors: Mykhalchenko Nataliya , Wiegratz Jörg
Published: July 2022

This briefing explores anti-fraud measures (AFMs) in Ghana, Nigeria and Sierra Leone. This is the last of three Briefings which examine the characteristics of AFMs across Africa. The findings confirm our earlier analyses concerning major anti-fraud measure drivers, actors, tools and controversies. These measures link matters of corporate competition, branding, consumer protection, industrial policy, capitalism and national politics, and are by now a component of economic policy and governance of various African states. A reflection on the data presented across the three Briefings concludes, and marks the end of the series.
Unveiling the structural, dynamical, elastic, and electronic properties of cuboid silver tetrathiotungstate by means of ab initio calculations
Authors: Ould-Mohamed Mounir , Ouahrani Tarik , Muñoz Alfonso , Errandonea Daniel
Published: July 2022

We present for the first time a theoretical study of the structural stability and physical properties of the newly synthesized Ag2WS4. The study contributes to a better understanding of its electronic and vibrational properties, which is fundamental for the optimization of the technological applications of Ag2WS4. Calculations have been carried out by means of density-functional theory. The obtained results support that Ag2WS4 is thermodynamically, mechanically, and dynamically stable in a tetragonal layered structure, in good agreement with experiments. Calculations have also been used to obtain phonon frequencies, their assignments, and the Raman scattering spectrum. Furthermore, we show that Ag2WS4 has a brittle structure, that is governed by van der Waals interactions, which favors its exfoliation as a low-dimensional structure. Additionally, the results show that Ag2WS4 has a band gap of 2.02 eV with a favorable band-edge diagram for water splitting as well as for optoelectronic applications.
Magnetic phase transition of monolayer chromium trihalides investigated with machine learning: toward a universal magnetic Hamiltonian
Authors: Zhang F , Zhang J , Nan H , Fang D , Zhang G-X , Zhang Y , Liu L , Wang D
Published: July 2022

The prediction of magnetic phase transitions often requires model Hamiltonians to describe the necessary magnetic interactions. The advance of machine learning provides an opportunity to build a unified approach that can treat various magnetic systems without proposing new model Hamiltonians. Here, we develop such an approach by proposing a novel set of descriptors that describes the magnetic interactions and training the artificial neural network (ANN) that plays the role of a universal magnetic Hamiltonian. We then employ this approach and Monte Carlo simulation to investigate the magnetic phase transition of two-dimensional monolayer chromium trihalides using the trained ANNs as energy calculator. We show that the machine-learning-based approach shows advantages over traditional methods in the investigation of ferromagnetic and antiferromagnetic phase transitions, demonstrating its potential for other magnetic systems.
Influence of gyro axis sequence configuration on the accuracy of alignment and navigation in a nested rotation inertial navigation system
Authors: Wang Meng , Wang Lei
Published: July 2022

It is analyzed that for a nested rotation inertial navigation system (NRINS) constructed from three ring fiber optic gyros nested within each other the main residual errors after rotation modulation are gyro angle random walk (ARW) and non-modulated gyro drift. It is pointed out that different orientations of the gyro sensitive axis lead to different equivalent ARWs, and the non-modulated gyro drift caused by the nested installation of three ring gyros is also different. The mechanism of generation of non-modulated drift in the embedded system and the general relationship with the axis sequence configuration are expounded. The equivalent ARW and non-modulated gyro drift in the inner frame rotation modulation mode and their influence on the alignment and navigation of the system are analyzed and deduced. Finally, taking the two typical applications of short-time and long-time navigation as examples, the influence of different gyro axis sequence configuration schemes on the navigation accuracy of the NRINS is verified through static navigation experiments, and the best axis sequence configuration scheme under the two applications is determined. By optimizing the gyro axis sequence configuration, the accuracy of navigation can be improved by about two times, which is of great significance. This work has important reference value for further improving the accuracy of NRINS and maximizing the accuracy advantage of gyros in different applications.
An equivalent parameter geometric shape representation using independent coordinates of cubic Bézier control points
Authors: Zhenwei Wang , Ziyu Zhang , Shuro Nakajima , Hong Chen
Published: July 2022

Bézier surface has been commonly applied to represent the complex geometric shape. Generally, all control points are dealt with by the same blending functions, regardless of the effect of independent coordinate. It causes to lack the modeling flexibility. Therefore, this paper proposes an equivalent parameter geometric shape representation method using the independent coordinates of control points. Since the coordinate components of control points are independent, the geometric modeling becomes more flexible. Firstly, a general Bézier curve is described in detail. Related expression is brought out in the form of independent coordinates by introducing two parameters. Then, their geometric meanings are analyzed in detail. Since both parameters are independent to parametric variables u and v, Bézier curve possess the same interval in the discrete parametric space, namely equivalent parameter. Next, a bicubic Bézier subsurface patch representation is discussed, including regular and non-regular subsurface patch. A general surface expression is given out in the form of independent coordinates, as well as the parameter structure and the geometric transformations. Finally, an example of ‘Bézier tree branch’ is constructed by using the proposed method. Results shows that the proposed method is feasible and reasonable.
Modeling the propagation of tumor fronts with shortest path and diffusion models—implications for the definition of the clinical target volume
Authors: Bortfeld Thomas , Buti Gregory
Published: July 2022

Objective. The overarching objective is to make the definition of the clinical target volume (CTV) in radiation oncology less subjective and more scientifically based. The specific objective of this study is to investigate similarities and differences between two methods that model tumor spread beyond the visible gross tumor volume (GTV): (1) the shortest path model, which is the standard method of adding a geometric GTV-CTV margin, and (2) the reaction-diffusion model. Approach. These two models to capture the invisible tumor ‘fire front’ are defined and compared in mathematical terms. The models are applied to example cases that represent tumor spread in non-uniform and anisotropic media with anatomical barriers. Main results. The two seemingly disparate models bring forth traveling waves that can be associated with the front of tumor growth outward from the GTV. The shape of the fronts is similar for both models. Differences are seen in cases where the diffusive flow is reduced due to anatomical barriers, and in complex spatially non-uniform cases. The diffusion model generally leads to smoother fronts. The smoothness can be controlled with a parameter defined by the ratio of the diffusion coefficient and the proliferation rate. Significance. Defining the CTV has been described as the weakest link of the radiotherapy chain. There are many similarities in the mathematical description and the behavior of the common geometric GTV-CTV expansion method, and the definition of the CTV tumor front via the reaction-diffusion model. Its mechanistic basis and the controllable smoothness make the diffusion model an attractive alternative to the standard GTV-CTV margin model.
Issues in the automated classification of multilead ecgs using heterogeneous labels and populations
Authors: Reyna Matthew A , Sadr Nadi , Perez Alday Erick A , Gu Annie , Shah Amit J , Robichaux Chad , Bahrami Rad Ali , Elola Andoni , Seyedi Salman , Ansari Sardar , Ghanbari Hamid , Li Qiao , Sharma Ashish , Clifford Gari D
Published: July 2022

Objective. The standard twelve-lead electrocardiogram (ECG) is a widely used tool for monitoring cardiac function and diagnosing cardiac disorders. The development of smaller, lower-cost, and easier-to-use ECG devices may improve access to cardiac care in lower-resource environments, but the diagnostic potential of these devices is unclear. This work explores these issues through a public competition: the 2021 PhysioNet Challenge. In addition, we explore the potential for performance boosting through a meta-learning approach. Approach. We sourced 131,149 twelve-lead ECG recordings from ten international sources. We posted 88,253 annotated recordings as public training data and withheld the remaining recordings as hidden validation and test data. We challenged teams to submit containerized, open-source algorithms for diagnosing cardiac abnormalities using various ECG lead combinations, including the code for training their algorithms. We designed and scored the algorithms using an evaluation metric that captures the risks of different misdiagnoses for 30 conditions. After the Challenge, we implemented a semi-consensus voting model on all working algorithms. Main results. A total of 68 teams submitted 1,056 algorithms during the Challenge, providing a variety of automated approaches from both academia and industry. The performance differences across the different lead combinations were smaller than the performance differences across the different test databases, showing that generalizability posed a larger challenge to the algorithms than the choice of ECG leads. A voting model improved performance by 3.5%. Significance. The use of different ECG lead combinations allowed us to assess the diagnostic potential of reduced-lead ECG recordings, and the use of different data sources allowed us to assess the generalizability of the algorithms to diverse institutions and populations. The submission of working, open-source code for both training and testing and the use of a novel evaluation metric improved the reproducibility, generalizability, and applicability of the research conducted during the Challenge.
Breakdown voltage in long tubes: the effect of surface charge
Authors: Meshchanov A V , Shishpanov A I , Bazhin P S , Ionikh Y Z
Published: July 2022

The study focuses on ignition processes in long discharge tubes (the length of which is large compared to the diameter) in rare gases Ne, Ar, and their mixture at a low pressure (∼1 Torr). Gas breakdown was caused by ramp voltage pulses of positive or negative polarity applied to the active electrode. The breakdown voltage was determined by the voltage drop at breakdown. The emission of the ionization wave (IW) preceding the breakdown was explored. The discharge tubes were exposed to two types of external influences. The first was illumination of the tube cathode with visible spectrum light, while the second was the constant or pulsed bias of the cathode potential by a value lower than that of maintaining discharge. In both cases the breakdown voltage increased up to doubling under some conditions. The observation of the IW revealed the presence of extra waves preceding the regular pre-breakdown IW. The extra wave velocity and emission intensity differed from those of the regular waves. Their main feature is that they do not overcome the entire inter-electrode gap, but weaken and disappear in between. It is assumed that the extra waves deposit the wall surface charge, which in turn affects the breakdown voltage. The increased breakdown voltage value remains for tens of minutes, which could indicate the surface charge lifetime of the same order. This was confirmed by direct wall-potential measurements using an electrostatic voltmeter.
Dynamical fluctuations in fragmentation reactions in a Boltzmann–Langevin approach
Authors: Li Bing , Tang Na , Zhang Feng-Shou
Published: July 2022

Based on the isospin-dependent Boltzmann–Langevin model, the dynamical fluctuations in the fragmentation reaction of 112Sn+112Sn are investigated. The quadrupole moment and octupole moment with zero magnetic quantum number have large fluctuations in the early time of the collisions. The dynamical fluctuations in momentum space show a strong dependence on the incident energy. The effects of using different fluctuations on the fragment cross sections are also studied in the fragmentation reactions. The results by using Q
20 + Q
30 fluctuation have a better agreement with the experimental data. Calculations using Q
20 + Q
30 fluctuation produce more proton-rich and neutron-rich nuclei than those using Q
20 fluctuation only. Besides, the difference between the production cross sections of fragments calculated by using Q
20 and Q
20 + Q
30 fluctuations is larger in the vicinity of the projectile. These results present that the dynamical fluctuations may affect the whole dynamical process of fragmentation reactions including the production of fragments, due to the nonlinear nature of the Boltzmann–Langevin equation.
Tighter monogamy relations of entanglement measures based on fidelity
Authors: Zhang Meiming , Jing Naihuan
Published: July 2022

We study the Bures measure of entanglement and the geometric measure of entanglement as special cases of entanglement measures based on fidelity, and find their tighter monogamy inequalities over tri-qubit systems as well as multi-qubit systems. Furthermore, we derive the monogamy inequality of concurrence for qudit quantum systems by projecting higher-dimensional states to qubit substates.
Investigating color screening in proton-nucleus collisions with complex potentials*
Authors: Wen Liuyuan , Du Xiaojian , Shi Shuzhe , Chen Baoyi
Published: July 2022

Color screening and parton inelastic scattering modify the heavy-quark antiquark potential in mediums consisting of particles from quantum chromodynamics (QCD), leading to the suppression of quarkonium production in relativistic heavy-ion collisions. Owing to the small charm/anti-charm (

) pair production number in proton-nucleus (pA) collisions, the correlation between different

pairs is negligible, which makes the Schrödinger equation viable for tracking the evolution of only one

pair. We employ the time-dependent Schrödinger equation with an in-medium

potential to study the evolution of charmonium wave functions in a hydrodynamic-like QCD medium produced in pA collisions. We explore different parametrizations of real and imaginary parts of the

potential and calculate the nuclear modification factors (

) of

and

in

TeV energy p-Pb collisions at the Large Hadron Collider (LHC). Comparing strong and weak screening scenarios with experimental data in this approach, we arrive at the conclusion that color screening is weak at temperatures close to the deconfined phase transition. Moreover, the imaginary part of the potential is crucial in describing the experimental data, which is consistent with widely studied semi-classical approaches, where dissociation rates are essential.
Systematic study on α-decay half-lives of uranium isotopes with a screened electrostatic barrier*
Authors: Xu Yang-Yang , Zhu De-Xing , Zou You-Tian , Wu Xi-Jun , He Biao , Li Xiao-Hua
Published: July 2022

In the present work, we systematically study the α-decay half-lives of uranium (Z=92) isotopes based on the Gamow model with a screened electrostatic barrier. There are only two adjustable parameters in our model i.e. the parameter g and the screening parameter t in the Hulthen potential for considering the screened electrostatic effect of the Coulomb potential. The calculated results are in good agreement with experimental data, and the corresponding root-mean-square (rms) deviations of uranium isotopes with α transition orbital angular momentum l=0 and l=2 are 0.141 and 0.340, respectively. Moreover, we extend this model to predict α-decay half-lives of uranium isotopes whose α decay is energetically allowed or observed but not yet quantified in NUBASE2020. For comparison, the modified Hatsukawa formula (XLZ), the unified Royer formula (DZR), the universal decay law (UDL) and the Viola–Seaborg–Sobiczewski formula (VSS) are also used. The predictions are basically consistent with each other. Meanwhile, the results also indicate that N=126 shell closure is still robust at Z=92 and the spectroscopic factor

is almost the same for uranium isotopes with the same l.
Time stability and connectivity analysis with an intracortical 96-channel microelectrode array inserted in human visual cortex
Authors: Grani Fabrizio , Soto-Sanchez Cristina , Farfan Fernando Daniel , Alfaro Arantxa , Grima Maria Dolores , Rodil Doblado Alfonso , Fernández Eduardo
Published: July 2022

Objective. Microstimulation via electrodes that penetrate the visual cortex creates visual perceptions called phosphenes. Besides providing electrical stimulation to induce perceptions, each electrode can be used to record the brain signals from the cortex region under the electrode which contains brain state information. Since the future visual prosthesis interfaces will be implanted chronically in the visual cortex of blind people, it is important to study the long-term stability of the signals acquired from the electrodes. Here, we studied the changes over time and the repercussions of electrical stimulation on the brain signals acquired with an intracortical 96-channel microelectrode array implanted in the visual cortex of a blind volunteer for 6 months. Approach. We used variance, power spectral density, correlation, coherence, and phase coherence to study the brain signals acquired in resting condition before and after the administration of electrical stimulation during a period of 6 months. Main results. Variance and power spectral density up to 750 Hz do not show any significant trend in the 6 months, but correlation coherence and phase coherence significantly decrease over the implantation time and increase after electrical stimulation. Significance. The stability of variance and power spectral density in time is important for long-term clinical applications based on the intracortical signals collected by the electrodes. The decreasing trends of correlation, coherence, and phase coherence might be related to plasticity changes in the visual cortex due to electrical microstimulation.
Nonlinear impact of the porous nanostructure on the net tungsten erosion in the linear plasma device PISCES-A
Authors: Yang K.R. , Dai S.Y. , Doerner R.P. , Liu D.H. , Chen J.Y. , Wang D.Z.
Published: July 2022

The tungsten fuzz growth under non-erosive and erosive helium plasmas in the linear plasma device PISCES-A has been investigated by experiments and simulations. The simulation results benchmarked against the experimental measurements indicate a decayed net physical sputtering yield during fuzz growth under the erosive helium plasma. Further, a nonlinear dependence of the net tungsten erosion on the ‘effective’ porous nanostructure that can be sputtered by incident helium particles has been found.
GPU-based optical simulation of the DARWIN detector
Authors: Althueser L. , Antunović B. , Aprile E. , Bajpai D. , Baudis L. , Baur D. , Baxter A.L. , Bellagamba L. , Biondi R. , Biondi Y. , Bismark A. , Brown A. , Budnik R. , Chauvin A. , Colijn A.P. , Cuenca-García J.J. , D'Andrea V. , Di Gangi P. , Dierle J. , Diglio S. , Doerenkamp M. , Eitel K. , Farrell S. , Ferella A.D. , Ferrari C. , Findley C. , Fischer H. , Galloway M. , Girard F. , Glade-Beucke R. , Grandi L. , Guida M. , Hansmann-Menzemer S. , Jörg F. , Jones L. , Kavrigin P. , Krauss L.M. , von Krosigk B. , Kuger F. , Landsman H. , Lang R.F. , Li S. , Liang S. , Lindner M. , Loizeau J. , Lombardi F. , Marrodán Undagoitia T. , Masbou J. , Masson E. , Matias-Lopes J. , Milutinovic S. , Monteiro C.M.B. , Murra M. , Ni K. , Oberlack U. , Ostrovskiy I. , Pandurovic M. , Peres R. , Qin J. , Rajado Silva M. , Ramírez García D. , Sanchez-Lucas P. , dos Santos J.M.F. , Schumann M. , Selvi M. , Semeria F. , Simgen H. , Steidl M. , Tan P.-L. , Terliuk A. , Thieme K. , Trotta R. , Tunnell C.D. , Tönnies F. , Valerius K. , Vetter S. , Volta G. , Wang W. , Wittweg C. , Xing Y.
Published: July 2022

Understanding propagation of scintillation light is critical for maximizing the discovery potential of next-generation liquid xenon detectors that use dual-phase time projection chamber technology. This work describes a detailed optical simulation of the DARWIN detector implemented using Chroma, a GPU-based photon tracking framework. To evaluate the framework and to explore ways of maximizing efficiency and minimizing the time of light collection, we simulate several variations of the conventional detector design. Results of these selected studies are presented. More generally, we conclude that the approach used in this work allows one to investigate alternative designs faster and in more detail than using conventional Geant4 optical simulations, making it an attractive tool to guide the development of the ultimate liquid xenon observatory.
Path integrals on sl(2, R) orbits
Authors: Ashok Sujay K , Troost Jan
Published: July 2022

We quantise orbits of the adjoint group action on elements of the sl

(

2
,
R

)

Lie algebra. The path integration along elliptic slices is akin to the coadjoint orbit quantization of compact Lie groups, and the calculation of the characters of elliptic group elements proceeds along the same lines as in compact groups. The computation of the trace of hyperbolic group elements in a diagonal basis as well as the calculation of the full group action on a hyperbolic basis requires considerably more technique. We determine the action of hyperbolic one-parameter subgroups of PSL

(

2
,
R

)

on the adjoint orbits and discuss global subtleties in choices of adapted coordinate systems. Using the hyperbolic slicing of orbits, we describe the quantum mechanics of an irreducible sl

(

2
,
R

)

representation in a hyperbolic basis and relate the basis to the mathematics of the Mellin integral transform. We moreover discuss the representation theory of the double cover SL

(

2
,
R

)

of PSL

(

2
,
R

)

as well as that of its universal cover. Traces in the representations of these groups for both elliptic and hyperbolic elements are computed. Finally, we motivate our treatment of this elementary quantization problem by indicating applications.
Cutting rules and positivity in finite temperature many-body theory
Authors: Hyrkäs M J , Karlsson D , van Leeuwen R
Published: July 2022

For a given diagrammatic approximation in many-body perturbation theory it is not guaranteed that positive observables, such as the density or the spectral function, retain their positivity. For zero-temperature systems we developed a method [2014 Phys. Rev. B
90 115134] based on so-called cutting rules for Feynman diagrams that enforces these properties diagrammatically, thus solving the problem of negative spectral densities observed for various vertex approximations. In this work we extend this method to systems at finite temperature by formulating the cutting rules in terms of retarded N-point functions, thereby simplifying earlier approaches and simultaneously solving the issue of non-vanishing vacuum diagrams that has plagued finite temperature expansions. Our approach is moreover valid for nonequilibrium systems in initial equilibrium and allows us to show that important commonly used approximations, namely the GW, second Born and T-matrix approximation, retain positive spectral functions at finite temperature. Finally we derive an analytic continuation relation between the spectral forms of retarded N-point functions and their Matsubara counterparts and a set of Feynman rules to evaluate them.
Potential of feed supplements on morphometric and gonad weight of fish exposed to microplastics
Authors: A’yun Q , Musthoza F S , Supartini S , Utari D , Listiani I , Triwahyudi H , Fikriyah N , Suprapti N , Hayati A
Published: July 2022

Microplastic can highly accumulated in fresh water, sea water, sedimentary, and marine life species. Its tiny size and large quantity cause it to become ubiquitous and highly bioavailable in aquatic organism. The potential of probiotic supplement from lactic acid bacteria and Vitamin C has proven effective and beneficial in remedial process of living organisms that exposed to toxic materials in microplastic. This research wants to analyze the potential of feed supplement on morphometric and gonad weight of fish exposed to microplastics. Thirty six tilapias divided into two groups; one group given feed variant (commercial pellet, mixture of commercial pellet and probiotic, and mixture of commercial pellet and Vitamin C) and other group given microplastic concentrate variant (0; 0,1; 1; and 10 mg/L) for 15 days. The result shows changes in morphometry and the weight of fish gonad. A significant microplastic exposure reduce the size of tilapia’s morphometry (body size, standard size, head size, and body width), go nad’s weight, and tilapia’s weight. The addition of probiotics increased the morphometry of tilapia exposed to microplastics.This research will give useful informations for fish farmers in developing fish resources and fish farming.
Monitoring the occurrence of Zoea Syndrome (ZS) in pacific white shrimp (Litopenaeus vannamei) larval from several hatcheries in East Java, Indonesia
Authors: Wiradana P A , Sani M D , Mawli R E , Ashshoffa F N D , Widhiantara I G , Mukti A T
Published: July 2022

This study aimed to evaluate Pacific white shrimp larval quality from several shrimp breeding centers in East Java. parameters measured include 1) bolitas, 2) abundance of Vibrio spp. (water and shrimp body), and 3) muscle gut ratio (MGR). Larval samples were collected from 8 hatcheries located in East Java. The results showed that the percentage of bolitas in the hepatopancreas organ of shrimp larval in ponds 6, 7, and 8, respectively was <35%. Larval guts were found in all hatcheries, except for the 2nd pond as many as 60%. The highest abundance of Vibrio spp. (yellow colonies) in water samples and fry bodies was found in the 6th pond (26.5 × 103 CFU mL-1) and the 4th pond (76.9 × 103 CFU gr-1). The abundance of Vibrio spp. (green colony) and the highest water sample was found in the 3rd pond (3.8 × 103 CFU mL-1), while the larval was not detected. The larval found the highest percentage of MGR in the 3rd pond (87.5%), and the lowest was in the 7th pond (57.50%). Overall, our results demonstrate the infection of Vibrio spp. has involvement in the incidence of zoea syndrome in pacific white shrimp fry in hatcheries.
Bacterial Viability of Edwardsiella tarda from Silver Rasbora (Rasbora argyrotaenia) after Infection with Immmersion Methods
Authors: Husna N , Kusdarwati R , Ulkhaq M F
Published: July 2022

Silver rasbora (Rasbora argyrotaenia) is a freshwater fishery commodity that has high economic value. However, fulfilling the demand for silver rasbora still relies on catches from nature, so cultivation is needed. The problem that occurs in the cultivation process is the Edwardsiella tarda infection which causes Edwardsiellosis disease. The purpose of this study was to determine the bacterial viability of E. tarda from silver rasbora after infection with immersion methods. The Total Plate Count (TPC) from blood, liver and kidney was taken from infected fish after 14 days immersion with bacterial suspension. The results showed that E. tarda infection had occurred in the blood, liver and kidneys as indicated by an increasing the density of bacteria in each organ along with the increasing of the concentration of infected bacteria. The highest density of E. tarda bacteria infected in silver rasbora was in the blood and the least was in the kidneys.