bluuebunny/crossref_metadata_2025 huggingface dataset:
Exactly solvable discrete time birth and death processes
Authors: Sasaki Ryu
Published: June 2022

We present 15 explicit examples of discrete time birth and death processes which are exactly solvable. They are related to hypergeometric orthogonal polynomials of the Askey scheme having discrete orthogonality measures. Namely, they are the Krawtchouk, three different kinds of q-Krawtchouk, (dual, q)-Hahn, (q)-Racah, Al-Salam–Carlitz II, q-Meixner, q-Charlier, dual big q-Jacobi, and dual big q-Laguerre polynomials. The birth and death rates are determined by using the difference equations governing the polynomials. The stationary distributions are the normalized orthogonality measures of the polynomials. The transition probabilities are neatly expressed by the normalized polynomials and the corresponding eigenvalues. This paper is simply the discrete time versions of the known solutions of the continuous time birth and death processes.
A generic model for pandemics in networks of communities and the role of vaccination
Authors: Antonopoulos Chris G. , Akrami M. H. , Basios Vasileios , Latifi Anouchah
Published: June 2022

The slogan “nobody is safe until everybody is safe” is a dictum to raise awareness that in an interconnected world, pandemics, such as COVID-19, require a global approach. Motivated by the ongoing COVID-19 pandemic, we model here the spread of a virus in interconnected communities and explore different vaccination scenarios, assuming that the efficacy of the vaccination wanes over time. We start with susceptible populations and consider a susceptible–vaccinated–infected–recovered model with unvaccinated (“Bronze”), moderately vaccinated (“Silver”), and very-well-vaccinated (“Gold”) communities, connected through different types of networks via a diffusive linear coupling for local spreading. We show that when considering interactions in “Bronze”–“Gold” and “Bronze”–“Silver” communities, the “Bronze” community is driving an increase in infections in the “Silver” and “Gold” communities. This shows a detrimental, unidirectional effect of non-vaccinated to vaccinated communities. Regarding the interactions between “Gold,” “Silver,” and “Bronze” communities in a network, we find that two factors play a central role: the coupling strength in the dynamics and network density. When considering the spread of a virus in Barabási–Albert networks, infections in “Silver” and “Gold” communities are lower than in “Bronze” communities. We find that the “Gold” communities are the best in keeping their infection levels low. However, a small number of “Bronze” communities are enough to give rise to an increase in infections in moderately and well-vaccinated communities. When studying the spread of a virus in dense Erdős–Rényi and sparse Watts–Strogatz and Barabási–Albert networks, the communities reach the disease-free state in the dense Erdős–Rényi networks, but not in the sparse Watts–Strogatz and Barabási–Albert networks. However, we also find that if all these networks are dense enough, all types of communities reach the disease-free state. We conclude that the presence of a few unvaccinated or partially vaccinated communities in a network can increase significantly the rate of infected population in other communities. This reveals the necessity of a global effort to facilitate access to vaccines for all communities.
The appearance of particle tracks in detectors. II. The semi-classical realm
Authors: Benoist Tristan , Fraas Martin , Fröhlich Jürg
Published: June 2022

The appearance of tracks, close to classical orbits, left by charged quantum particles propagating inside a detector, such as a cavity periodically illuminated by light pulses, is studied for a family of idealized models. In the semi-classical regime, which is reached when one considers highly energetic particles, we present a detailed, mathematically rigorous analysis of this phenomenon. If the Hamiltonian of the particles is quadratic in position- and momentum operators, as in the examples of a freely moving particle or a particle in a homogeneous external magnetic field, we show how symmetries, such as spherical symmetry, of the initial state of a particle are broken by tracks consisting of infinitely many approximately measured particle positions and how, in the classical limit, the initial position and velocity of a classical particle trajectory can be reconstructed from the observed particle track.
Coherent acoustic modulation and defect-sensitive ultrafast carrier dynamics of Pr0.5Ca0.5MnO3 thin films investigated by time-resolved terahertz spectroscopy
Authors: Kinha Monu , Udeshi Malay , Dagar Rahul , Rana D. S.
Published: June 2022

In transition metal oxides, the potential of competing energetics of interacting fundamental entities is best displayed in perovskite manganites via the formation of a variety of exotic phases; however, there are limitations of extreme sensitivity to extrinsic and intrinsic defects and the slightest of structural modulations. Here, we report the effect of oxygen annealing and epitaxial strain on the ultrafast carrier excitation and relaxation mechanism in charge-ordered (CO) manganite Pr0.5Ca0.5MnO3 (PCMO) thin films of 60 and 150 nm thicknesses, both as-grown and oxygen annealed, as investigated by optical pump–terahertz (THz) probe measurements. Transient THz transmittance is negative for both films. Bi-exponential relaxation behavior accompanied with acoustic modulations was observed that varies along with strain and oxygen content of the films. As fitted by the sum of exponentials, the fast relaxation time constant is found to be fluence independent, while the slow relaxation time constant decreases with pump fluence for both films and is less for the annealed film suggesting that the relaxation in PCMO strongly depends on strain and oxygen content. This study on non-equilibrium carrier dynamics depicting the sensitivity of defects and subtle structural modifications is unprecedented in demonstrating the ultrafast control of CO manganites.
Efficient simulation of rarefied gas flow past a particle: A boundary element method for the linearized G13 equations
Authors: Padrino Juan C. , Sprittles James E. , Lockerby Duncan A.
Published: June 2022

We develop a novel boundary integral formulation for the steady linearized form of Grad's 13-moment (G13) equations applied to a uniform flow of rarefied gas past solid objects at low Mach numbers. Changing variables leads to a system of boundary integral equations that combines integral equations from Stokes flow and potential theory. The strong coupling between the stress deviator and heat flux featured by the G13 equations demands adding a boundary integral equation for the pressure. We specialize the integral equations for an axisymmetric flow with no swirl and derive the axisymmetric fundamental solutions for the pressure equation, seemingly absent in the Stokes-flow literature. Using the boundary element method to achieve a numerical solution, we apply this formulation to streaming flow of rarefied gas past prolate or oblate spheroids with their axis of symmetry parallel to the free stream, considering various aspect ratios and Knudsen numbers—the ratio of the molecules' mean free path to the macroscopic length scale. After validating the method, we obtain the surface profiles of the deviations from the unperturbed state of the traction, heat flux, pressure, temperature, and slip velocity, as well as the drag on the spheroid, observing convergence with the number of elements. Rarefaction phenomena, such as temperature jump and polarization, Knudsen effects in the drag, and velocity slippage, are predicted. This method opens a new path for investigating other gas non-equilibrium phenomena that can be modeled by the same set of equations, such as thermophoresis, and has application in nano- and microfluidics.
NSR singular vectors from Uglov polynomials
Authors: Bershtein Mikhail , Vargulevich Angelina
Published: June 2022

It was conjectured by Belavin et al. [J. High Energy Phys. 2013(3), 35] that bosonization of a singular vector (in the Neveu–Schwarz sector) of the N=1 super analog of the Virasoro algebra can be identified with the Uglov symmetric function. In this paper, we prove this conjecture. We also extend this result to the Ramond sector of the N=1 super-Virasoro algebra.
Phospholipid acyl tail affects lipid headgroup orientation and membrane hydration
Authors: Maltseva Daria , Gonella Grazia , Ruysschaert Jean-Marie , Bonn Mischa
Published: June 2022

Biomembrane hydration is crucial for understanding processes at biological interfaces. While the effect of the lipid headgroup has been studied extensively, the effect (if any) of the acyl chain chemical structure on lipid-bound interfacial water has remained elusive. We study model membranes composed of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) lipids, the most abundant lipids in biomembranes. We explore the extent to which the lipid headgroup packing and associated water organization are affected by the lipid acyl tail unsaturation and chain length. To this end, we employ a combination of surface-sensitive techniques, including sum-frequency generation spectroscopy, surface pressure measurements, and Brewster angle microscopy imaging. Our results reveal that the acyl tail structure critically affects the headgroup phosphate orientational distribution and lipid-associated water molecules, for both PE and PC lipid monolayers at the air/water interface. These insights reveal the importance of acyl chain chemistry in determining not only membrane fluidity but also membrane hydration.
Memristive functionality based on viscous magnetization dynamics
Authors: Ivanov Sergei , Urazhdin Sergei
Published: June 2022

In viscous dynamics, velocity is proportional to the force. An ideal memristor is a device whose resistance changes at a rate proportional to the driving input. We present a proof-of-principle demonstration of the connection between viscous dynamics and memristive functionality by utilizing a thin-film ferromagnet/antiferromagnet bilayer, where viscous magnetization dynamics results from the frustration at the magnetic interface, and driving is provided by an external magnetic field. Thanks to the atomic scale of frustration effects, the presented approach is amenable to downscaling. It can also be adapted for electronic driving by spin torque, making it attractive for applications in neuromorphic circuits.
Predicting the fine fuel moisture content in Dalmatian black pine needle litter
Authors: Bakšić Nera , Bakšić Darko
Published: June 2022

During the last three decades, there has been an increase in the incidence of severe crown fires affecting black pine forests in the sub-Mediterranean area. The objective of this study was to develop and test a model to predict fine fuel moisture content for Dalmatian black pine (Pinus nigra J.F. Arnold subsp. dalmatica (Vis.) Franco) needle litter. We performed laboratory measurements of equilibrium moisture content and response time of dead black pine needles to modify the hourly fine fuel moisture code (FFMC) model, and we compared the predictive ability of the hourly FFMC model with that of modified model (PnFFMC). Field tests showed that although the hourly FFMC model reproduced trends in moisture content of black pine needles quite well, it consistently overestimated moisture content (mean absolute error 3.9%). The PnFFMC model performed better than the hourly FFMC model and was closer to the line of equivalence (mean absolute error 0.9%). This study indicates that the hourly FFMC can easily be modified by incorporating appropriate species-specific equilibrium moisture content and response time values, leading to more accurate predictions of fine fuel moisture content. The need to use recently fallen needles in fuel moisture modelling for Mediterranean pine species is highlighted.
Intersubjectification in constructional change*
Authors: Hilpert Martin , Bourgeois Samuel
Published: June 2022

This chapter addresses constructional change in a dialogical construction that is illustrated by utterances such as sarcastic much?, which typically serve the purpose of an interactional challenge. Drawing on web-based corpus data, we argue that this construction is currently undergoing a process of change that expands its range of possible uses. Specifically, we observe the emergence of uses with a different intersubjective function, in which the writer does not aim for confrontation but is rather seeking the solidarity and alignment of the addressee. We offer an account of this development in terms of constructional change, and we use this case study to explore how intersubjectification and the dialogic nature of language can be accommodated more thoroughly in a constructional theory of language change.
What does deixis tell us about motion typology?
Authors: Morita Takahiro
Published: June 2022

This chapter discusses whether Deixis is genuinely a subcomponent of Path, as defined in Talmy’s motion typology. Although previous studies have already pointed out several characteristics of Deixis that distinguish it from other non-Deictic Path components, its typological status remains vague and should be better defined. In this chapter, based on a video-based production experiment in Japanese and French, I argue that Deictic verbs have a functional meaning in both languages, and that this functional meaning of Deixis can be considered a subcomponent of Path, as it is motivated by the speaker’s and Figure’s relative position and Ground schema. Based on analyses with reference to different Deictic expressions, I also propose another typology of the ways in which speakers of different languages organize their “here” space vis-à-vis perceived physical events.
Linguistic representations of visual motion
Authors: Matsumoto Yo , Akita Kimi , Bordilovskaya Anna , Eguchi Kiyoko , Koga Hiroaki , Mano Miho , Matsuse Ikuko , Morita Takahiro , Nagaya Naonori , Takahashi Kiyoko , Takahashi Ryosuke , Yoshinari Yuko
Published: June 2022

Linguistic expressions of visual motion (e.g., look into the building) in ten languages are compared, based on a crosslinguistic production experiment. We examine how linguistic representations of visual motion are typologically akin to those of self- and caused motion events. The results suggest that speakers frequently refer to path in describing visual motion events, using the “Implicit-figure construction”, where no overt argument of V moves. Head-external path-coding languages allow path to be expressed similarly to how it is expressed in descriptions of self- and caused motion events, whereas head path-coding languages use different strategies. For visual motion, the use of path verbs and deictic verbs is avoided in most languages. Patterns of the representation of visual motion thus reveal a wider range of crosslinguistic variations in describing motion events than previously thought.
Source–Goal asymmetry in German
Authors: Guse Laura
Published: June 2022

Following years of intensive research in the field of motion event representation and its encoding in language, it can be concluded that goal paths are predominantly privileged over source paths across many languages and different event types (e.g., Ikegami 1987, Lakusta and Landau 2005, Stefanowitsch and Rohde 2004, Song, this volume). This chapter has two aims: first, to cover the aspect of the granularity of lexicalization patterns encoding goal and source paths in the German language based on qualitative analysis and second, to show that in language, the factors animacy and volition are not mapped onto syntactic structures and do not directly influence the frequency of encoding goal paths. The quantitative corpus study reveals verb-specific preferences for encoding different path elements.
Acquisition of non-native vowel duration contrasts through classroom education
Authors: Saloranta Antti , Heikkola Leena Maria
Published: June 2022

In quantity languages, the durations of segments affect the meanings of words. This can present problems for second language (L2) learners who do not already have this feature in their native language. This study examines the effects of an intensive, four-week language course with a communicative focus on the perception and production of non-native vowel duration contrasts. A total of 68 students of Finnish, divided into speakers of quantity or non-quantity languages, took part in identification and production tests before and after taking part in the course. The course produced a significant improvement on identification, but not production. Furthermore, a slight advantage was found for speakers of quantity languages in the identification task. Comparison to native control groups revealed significant differences between groups in both tasks. The results are discussed in relation to the interaction of perception and production, L2 learning models and relevance to L2 teaching.
A sociolinguistic approach to the concept of translation ‘error’ in non-professional translation
settings
Authors: Lees Christopher
Published: June 2022

This paper proposes a sociolinguistic approach to understanding the phenomenon of divergence from the standard
norms of English that can be observed in public texts in the Greek city of Thessaloniki’s translation landscape. This approach
fits in with the growing body of research that recognises that not all translations are carried out by professional translators.
Certainly in the case of Thessaloniki, translations are typically carried out by non-professionals who draw on the linguistic
experience and resources they possess in order to communicate with visitors and residents who do not understand Greek. As a
result, several linguistic and pragmatic divergences from Standard English can be observed in the target text, which native
speakers of English seem to be willing to disregard, provided that the message is intelligible. The sociolinguistic approach
adopted in this paper reveals the translators’ effective use of the English language in conveying the message of the Greek source
text, on the basis of the judgements expressed by translation professionals as well as native speakers of Greek and English.
The CCL-K11 ongoing key comparison. Final report for 2021
Authors: Matus M , Zelenika S , Stanković N , Küng A , Balling P , Křen P , Zechner G
Published: June 2022

Main text

Four lasers from three national metrological institutes (NMIs) were compared in the year 2021 as part of the CCL-K11 ongoing key comparison, initiated by the 13th meeting of the Comité Consultative des Longuers (CCL) in 2007. The absolute frequency of R(127) 11-5 (≈633 nm) and of R(56) 32-0 (≈532 nm) transitions of molecular iodine was measured for these lasers following the technical protocol for CCL-K11. The results of these measurements are compiled in the present report. The comparison reports, as communicated by each participant, are included in the main document.

For the very first time in this key-comparison a standard working on a different operating principle is reported. CMI participated with a frequency doubled Nd:YAG laser stabilized to an iodine transition (Designation: CMI-YAG1). The technical protocol was deliberately designed to accommodate artefacts of different wavelengths in a common framework. Moreover, CMI participated with a second laser standard also. The institute has different CMC entries for the two laser types. Both entries refer to the same service category of highest metrological level, but are technically well separated. Due to the layout of CCL-K11 the KCRV is immune to a multiple participation of a single NMI. It was thus considered to include both measurements in this report.

This document constitutes the 11th final report for the ongoing key comparison CCL-K11.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Asymptotically hyperboloidal initial data sets from a parabolic–hyperbolic formulation of the Einstein vacuum constraints
Authors: Beyer F , Ritchie J
Published: June 2022

In this paper we continue our investigations of Rácz’s parabolic–hyperbolic formulation of the Einstein vacuum constraints. Our previous studies of the asymptotically flat setting provided strong evidence for unstable asymptotics which we were able to resolve by introducing a certain modification of Rácz’s parabolic–hyperbolic formulation. The primary focus of the present paper here is the asymptotically hyperboloidal setting. We provide evidence through a mixture of numerical and analytical methods that the asymptotics of the solutions of Rácz’s parabolic–hyperbolic formulation are stable, and, in particular, no modifications are necessary to obtain solutions which are asymptotically hyperboloidal.
A note on the pp-wave solution of minimal massive 3D gravity coupled with Maxwell–Chern–Simons theory
Authors: Cebeci Hakan , Dereli Tekin , Şentorun Seçil
Published: June 2022

In this work, we examine a family of pp-wave solutions of minimal massive 3D gravity minimally coupled with the Maxwell–Chern–Simons theory. An elaborate investigation of the field equations shows that the theory admits pp-wave solutions provided that there exist an anti-self duality relation between the electric and the magnetic components of the Maxwell two-form field. By employing Noether–Wald formalism, we also construct Noether charges of the theory within exterior algebra formalism.
Unipolar resistive switching behavior in MoS2–polyvinyl alcohol-based memory device
Authors: Liu Lifu , Cheng Shijie , Chen Wei , Ren Shuxia , Kang Xin , Zhao Xu
Published: June 2022

MoS2–polymer-based memory devices have attracted significant interest owing to their mechanical flexibility, convenient solution processability, and affordability. These devices exhibit bipolar resistive switching behavior, and their switching relies on the polarity of the applied bias. This paper presents a memory device in which a MoS2–polyvinyl alcohol (PVA) hybrid film is sandwiched between Ag and Pt electrodes. The developed Ag/MoS2–PVA/Pt device manifests typical unipolar resistive switching (URS) behavior and nonvolatile rewritable memory performance with a low operating voltage, large ON/OFF ratio (105), and multilevel cell storage ability. Notably, 1T-phase MoS2 is crucial for the URS behavior, and this switching behavior can be ascribed to the charge trapping as well as the Joule-heating-induced de-trapping of the S vacancies associated with 1T MoS2. These findings can facilitate the development of new designs for high-performance, high-density data storage.
Inverted spike-rate-dependent plasticity due to charge traps in a metal-oxide memristive device
Authors: Mishchenko M A , Bolshakov D I , Lukoyanov V I , Korolev D S , Belov A I , Guseinov D V , Matrosov V V , Kazantsev V B , Mikhaylov A N
Published: June 2022

We develop a model of Au/Ta/ZrO2(Y)/Ta2O5/TiN/Ti memristive devices and demonstrate, both experimentally and numerically, an inverted spike-rate-dependent plasticity effect. The effect consists of the reduction of the learning rate with an increase in the frequency of spikes generated by the phase-locked loop neuron. The memristor model uses two internal state variables representing the number of complete filaments and the concentration of the charged traps. While the former state variable defines the device resistance and is associated with the distribution of oxygen vacancies, the latter affects the internal electric field and modulates the migration of vacancies. Several neural circuit configurations that include pairs and populations of memristively coupled neurons are analyzed numerically. The results of this study may contribute to the development of large-scale self-organized artificial cognitive systems based on neural synchrony.
Stable structures and superconducting properties of Ca–La–H compounds under pressure
Authors: Yang KaiPing , Sun HuiJuan , Chen HaiLiang , Chen LingYan , Li BingYu , Lu WenCai
Published: June 2022

The calcium hydrides and lanthanum hydrides under high pressures have been reported to have good superconducting properties with high-T
C. In this work, the structures and superconductivities of Ca–La–H ternary hydrides have been studied by genetic algorithm and density functional theory calculations. Our results show that at the pressure range of 100–300 GPa, the most stable structure of CaLaH12 has a Cmmm symmetry, in which there is a H24 hydrogen cage. It can be expected to have high possibility to be synthesized due to its large stability. Furthermore, the predicted T
C of the Cmmm-CaLaH12 structure is about 140 K at 150 GPa, and when the pressure decreases to 30 GPa, the CaLaH12 structure with a C2/m symmetry has a predicted T
C of about 49 K. The CaLaH12 is suggested to be a stable good superconductor with large stability and performs well at relatively low pressures.
Dynamic imaging using motion-compensated smoothness regularization on manifolds (MoCo-SToRM)
Authors: Zou Qing , Torres Luis A , Fain Sean B , Higano Nara S , Bates Alister J , Jacob Mathews
Published: June 2022

Objective. We introduce an unsupervised motion-compensated reconstruction scheme for high-resolution free-breathing pulmonary magnetic resonance imaging. Approach. We model the image frames in the time series as the deformed version of the 3D template image volume. We assume the deformation maps to be points on a smooth manifold in high-dimensional space. Specifically, we model the deformation map at each time instant as the output of a CNN-based generator that has the same weight for all time-frames, driven by a low-dimensional latent vector. The time series of latent vectors account for the dynamics in the dataset, including respiratory motion and bulk motion. The template image volume, the parameters of the generator, and the latent vectors are learned directly from the k-t space data in an unsupervised fashion. Main results. Our experimental results show improved reconstructions compared to state-of-the-art methods, especially in the context of bulk motion during the scans. Significance. The proposed unsupervised motion-compensated scheme jointly estimates the latent vectors that capture the motion dynamics, the corresponding deformation maps, and the reconstructed motion-compensated images from the raw k-t space data of each subject. Unlike current motion-resolved strategies, the proposed scheme is more robust to bulk motion events during the scan.
Effect of inhomogeneities on the propagation of gravitational waves from binaries of compact objects
Authors: Pandey Shashank Shekhar , Sarkar Arnab , Ali Amna , Majumdar A.S.
Published: June 2022

We consider the propagation of gravitational waves in the late time Universe with the presence of structure. Before detection, gravitational waves emitted from distant sources have to traverse through regions of spacetime which are far from smooth and homogeneous. We investigate the effect of inhomogeneities on the observables associated with the gravitational wave sources. In particular, we evaluate the impact of inhomogeneities on gravitational wave propagation by employing Buchert's framework of averaging. In context of a toy model within the above framework, it is first shown how the redshift versus distance relation gets affected through the averaging process. We then study the variation of the redshift dependent part of the observed gravitational wave amplitude for different combination of our model parameters. We show that the variation of the gravitational wave amplitude with respect to redshift can deviate significantly compared to that in the ΛCDM-model. Our result signifies the importance of local inhomogeneities on precision measurements of parameters of gravitational wave sources.
Research on 2 μm polarization maintaining laser cavity based on the depolarization characteristics of a corner cube prism
Authors: Xie Gengchen , Wu Jing , Wu Yongfeng
Published: June 2022

Based on the Jones matrix theory, a polarization maintaining 2 μm ring laser with a cavity structure of corner cube prisms (CCPs) is firstly presented in this paper. The changes of polarization state are simulated and coincide with the corresponding 2.06 μm experimental results for output beams after the CCP. Research results show that if the incident beam is circularly polarized or linearly polarized, the output beam will be generally elliptically polarized. Only when the polarization azimuths of linearly polarized incident beams are 16.06°, 43.94°, 46.06° and 73.94° can the linearly polarized output beams with different polarization azimuth angles be obtained. As such an incident beam passes through two CCPs arranged in the same way according to four specially reflection sequences (ACB and BCA, BCA and ACB, BAC and CAB, CAB and BAC) respectively, the polarization maintaining 2 μm laser can be realized. This work provides a reference basis for the design of a 2 μm corner cube ring cavity laser to realize the preservation of polarization state, which have practical significance to improve the output characteristics of 2 μm laser.
Improving the scheme of bidirectional controlled teleportation with a five-qubit composite GHZ-Bell state
Authors: Yuan Hao , Zhang Gang , Xie Chuanmei , Zhang Zhanjun
Published: June 2022

A bidirectional controlled quantum state teleportation (BCQST) scheme was proposed by Li et al (2013 Int. J. Theor. Phys.
52 1630) using a five-qubit composite Greenberger–Horne–Zeilinger-Bell state as the quantum channel. However, it was found to be unsuccessful for bidirectional teleportation control due to its own security loopholes (Shukla et al 2013 Int. J. Theor. Phys.
52 3790). In this paper, we put forward an improved version of the BCQST scheme so that the loopholes are fixed and the bidirectional control can indeed be achieved. In addition, after the improvement, the revised scheme becomes more feasible in terms of present experimental techniques.
On the stabilisation of locked tearing modes in ITER and other large tokamaks
Authors: Nies Richard , Reiman Allan H. , Fisch Nathaniel J.
Published: June 2022

Tearing modes in tokamaks typically rotate while small and then lock at a fixed location when larger. Research on present-day devices has focused almost exclusively on stabilisation of rotating modes, as it has been considered imperative to avoid locked modes. However, in larger devices, stabilisation during the rotating phase is made difficult by fast locking at small island widths, and large broadening of the stabilising wave-driven current profile. In contrast, the smaller island width at locking not only mitigates the deleterious consequences of locked modes, but also permits their efficient stabilisation. On large devices, it thus becomes surprisingly advantageous to allow the mode to grow and lock naturally before stabilising it, challenging the mainstream strategy of neoclassical tearing mode stabilisation during the rotating phase. Calculations indicate that a locked island stabilisation strategy should be adopted in the ITER tokamak, with a large potential impact on the fusion gain and disruptivity.
Quench dynamics of the Anderson impurity model at finite temperature using matrix product states: entanglement and bath dynamics
Authors: Kohn Lucas , Santoro Giuseppe E
Published: June 2022

We study the dynamics of the quenched Anderson model at finite temperature using matrix product states (MPSs). Exploiting a chain mapping for the electron bath, we investigate the entanglement structure in the MPS for various orderings of the two chains, which emerge from the thermofield transformation employed to deal with nonzero temperature. We show that merging both chains can significantly lower the entanglement at finite temperatures as compared to an intuitive nearest-neighbor implementation of the Hamiltonian. Analyzing the population of the free bath modes—possible when simulating the full dynamics of impurity plus bath—we find clear signatures of the Kondo effect in the quench dynamics.
Entanglement Hamiltonian during a domain wall melting in the free Fermi chain
Authors: Rottoli Federico , Scopa Stefano , Calabrese Pasquale
Published: June 2022

We study the unitary time evolution of the entanglement Hamiltonian of a free Fermi lattice gas in one dimension initially prepared in a domain wall configuration. To this aim, we exploit the recent development of quantum fluctuating hydrodynamics. Our findings for the entanglement Hamiltonian are based on the effective field theory description of the domain wall melting and are expected to exactly describe the Euler scaling limit of the lattice gas. However, such field theoretical results can be recovered from high-precision numerical lattice calculations only when summing appropriately over all the hoppings up to distant sites.
Automatic detection of scintillation light splashes using conventional and deep learning methods
Authors: Jiang Y. , Bugby S.L. , Cosma G.
Published: June 2022

Six methods for the automatic detection of scintillation light splashes in a portable gamma camera are compared. Each imaging frame might contain any number of light splashes (including none), and the location and size of each light splash must be identified. For real-time imaging, splashes must be identified and characterised quickly and with minimal processing overhead. The techniques are compared on their ability to accurately determine the number, position, and size of light splashes, and to reconstruct the deposited energy within each splash for a simulated data set with known ground-truths. The speed of each technique and the ease of implementation are also discussed.

For accuracy in blob (light splash) localisation, a Laplacian of Gaussian approach was found to provide the most accurate estimation. However, its performance greatly relies on the appropriate tuning of preprocessing parameters prior to image analysis and the number of blobs in each frame. Deep learning approaches (Faster-RCNNs) performed significantly better than traditional algorithms in terms of predicting the size of each light splash, did not require image preprocessing and were also more stable over a range of frame occupancies.

Moreover, the paper fine-tuned a VGG16 based Faster-RCNN model with the simulated data set for the scintillation light splash detection, called DeepSplashSpotter (DSS).
Voltammetric investigation on iron-(nickel-)sulfur surface under conditions for the emergence of life
Authors: Altair T , Galante D , Varela H
Published: June 2022

Iron (II) sulfide minerals have gained attention in the last decades due to their relevance in hypotheses for the emergence of life on the early Earth around 4 billion years ago. In the submarine vent theory, it has been proposed that those minerals, especially mackinawite, had a key role in prebiotic processes. Those are estimated to be present in a natural electrochemical setting, analogous to a chemiosmotic one, formed in the interface between the early ocean and the interior of the alkaline hydrothermal systems, the early vent-ocean interface. To evaluate this and other hypotheses, voltammetric studies were performed to better understand the electrochemical behavior of minerals under conditions analogous to the vent-ocean interface. The preliminary results presented here indicate that, in the potential range estimated to exist in that interface, mackinawite can transition to other mineral phases and may posibly coexist with other minerals, resulting from its oxidation. This can create a local chemical diversity. In addition, it has been tested a protocol for Ni incorporation in mackinawite structure, resulting in a surface that showed an interesting behavior in the presence of CO2, although definitive experiments showed necessary for a deeper comprehension of that behavior. Overall, the results are consistent with previous results on electrocatalytical properties of Fe-Ni-S materials for CO2 reduction, and also could lead to the emergence of a protometabolism on early Earth.
External Corporate Governance Mechanisms: Linking Forces to Behaviors
Authors: Payne G. Tyge , Moore Curt
Published: June 2022

Corporate governance research has a long and varied history, having evolved from a broad number of scholarly disciplines, including sociology, law, finance, and management. Across these various disciplines, it is maintained that governance is essential to corporate success, as it provides strategic and ethical guidance to the company. While research has largely focused on internal mechanisms through which governance is enacted (such as ownership arrangements, board structures, managerial rewards and incentives, etc.), external forces and mechanisms are increasingly important to modern businesses. External corporate governance mechanisms emanate from outside the organization and support forces that promote governance structures, processes, and practices by top executives and board directors. Institutions, industries, markets, networks, and strong individual external stakeholders all work to influence corporate governance decisions and behaviors both directly and indirectly. The external forces induce mechanisms that influence desirable behaviors or intervene when internal mechanisms are compromised or ineffective.

Recent literature on external governance mechanisms can help scholars and practitioners develop a better understanding of this important area of inquiry, and future research should consider three broad suggestions to move the field forward: differentiating between forces and mechanisms; recognizing unique stakeholders, boundaries, and levels of analysis; and improving empirical designs to better recognize and understand what factors matter in instituting governance adjustments and behavior changes.
Meteorology in Vietnam, Pre-1850
Authors: Phung Hieu
Published: June 2022

The emergence of meteorology in Vietnam did not begin in 1898–1899, with the French installation of a central meteorological observatory in Phù Liễn, near Hải Phòng, and a network of meteorological stations across Indochina. Prior to the colonial time, the ethnic Vietnamese, as well as other ethnic groups such as the Cham, Muong, and Tay-Thai, developed their own knowledge of meteorological phenomena that functioned within their farming practices and cultural frameworks. While further research concerning traditional meteorological knowledge of minority groups in Vietnam is needed, substantial evidence allows a preliminary survey on the practices of the ethnic Vietnamese. Between 1000 and the 1850s, the Vietnamese expanded outwards from their original homeland in the lowlands of north and north-central Vietnam. They adopted the written language, thought systems, and technologies of imperial China, which predisposed them to an enduring Chinese-style meteorological ideology. The Vietnamese viewed weather extremes and other natural anomalies not merely as natural processes. Because meteorological phenomena were “Heaven-sent” warnings of cosmological disasters, Vietnamese dynastic rulers, as well as local farmers and rice producers, interpreted these signs as a demand for moral change. Redressing the authorities’ governance, according to their view, helped rehabilitate the equilibrium of the cosmos. Hence, the records of weather events in Vietnamese historical documents do not simply describe the conditions of past weather, but more importantly, the situations in which the cosmos was no longer in balance. One need not assume that premodern meteorology lacked material grounds. In Vietnam, meteorological knowledge and practices were strongly associated with wet rice cultivation. Vietnamese authorities maintained official agencies to produce yearly calendars that traced proper timing for rice crops, while the populace accumulated experience-based knowledge about seasonal rainfall. Intellectuals, too, expanded their interests to include meteorological knowledge because the subject enriched their philosophy of nature, as in the case of Confucian thinker Lê Quý Đôn (1726–1784), or their medical practices, as in the case of physician Lê Hữu Trác (1720–1791). The advances of Southeast Asian paleoclimate reconstruction since the beginning of the 21st century have added new ideas and methodologies to the study of premodern meteorology in Vietnam. A stronger partnership between climate scientists and historians will therefore facilitate more sophisticated investigations into the knowledge and practices that the Vietnamese developed to respond to weather and climate dynamics.
Lasso-adjusted treatment effect estimation under covariate-adaptive randomization
Authors: Liu Hanzhong , Tu Fuyi , Ma Wei
Published: June 2022

We consider the problem of estimating and inferring treatment effects in randomized experiments. In practice, stratified randomization, or more generally, covariate-adaptive randomization, is routinely used in the design stage to balance treatment allocations with respect to a few variables that are most relevant to the outcomes. Then, regression is performed in the analysis stage to adjust the remaining imbalances to yield more efficient treatment effect estimators. Building upon and unifying recent results obtained for ordinary-least-squares adjusted estimators under covariate-adaptive randomization, this paper presents a general theory of regression adjustment that allows for model mis-specification and the presence of a large number of baseline covariates. We exemplify the theory on two lasso-adjusted treatment effect estimators, both of which are optimal in their respective classes. In addition, nonparametric consistent variance estimators are proposed to facilitate valid inferences, which work irrespective of the specific randomization methods used. The robustness and improved efficiency of the proposed estimators are demonstrated through numerical studies.
Intergenerational transmission of parental smoking: when are offspring most vulnerable?
Authors: Alves J , Perelman J , Ramos E , Kunst A E
Published: June 2022

Background

Previous literature has showed that the likelihood of smoking is higher among offspring with smoking parents. The aim of this cohort study is to investigate during which smoking initiation stages and at what ages adolescents are more likely to be influenced by parental smoking.

Methods

This study used the EPITeen Cohort, which recruited 13-year-old adolescents born in 1990, enrolled at schools in Porto, Portugal. Participants (n = 996) were followed across four waves at 13, 17, 21 and 24 years old. We computed the odds ratio (OR) and 95% confidence intervals for the prevalence of the different smoking states (never smoking, experimenter, less than daily smoker, daily smoker and former smoker), and incidence transitions between these states (to smoking experimenter; to less than daily smoker, to daily smoker; to former smoker) as function of age, parental smoking status and their interaction.

Results

Compared with other participants, those with two smoking parents had an increased prevalence of experimentation at 13 years (OR for the interaction at 13 years compared with 24 years = 2.13 [1.50–3.01]) and daily smoking at all ages (OR for parental smoking =1.91 [1.52–2.40]). The latter increase is related to a significantly increased risk to transit from early smoking stages to daily smoking at all ages (OR for parental smoking = 1.83 [1.43–2.34]).

Conclusions

Parental smoking influences offspring’s daily smoking prevalence especially by increasing the risk to transit to daily smoking up to early adulthood. Prevention should focus on parents and parental influences especially among offspring who may transition to daily smokers.
Comparability of 24-hour composite and grab samples for detection of SARS-2-CoV RNA in wastewater
Authors: Kmush Brittany L , Monk David , Green Hyatt , Sachs† Darcy A , Zeng Teng , Larsen David A
Published: June 2022

Wastewater surveillance is a cost-effective way to monitor pathogen prevalence and transmission patterns in the entire community. Here, we compare 24-hour composite and grab samples collected during September 2020 from several municipalities in New York State to detect SARS-CoV-2. A total of 45 paired samples (90 total samples) from three counties and 14 wastewater treatment plants were available for analysis. The categorical comparison (SARS-CoV-2 genetic material detected and quantifiable, genetic material detected but below the limits of quantification, and genetic material not detected) between the grab and composite samples was quite strong, with 91.1% agreement (kappa P-value < .001). The correlations among the quantifiable grab and composite samples were statistically significant yet modest for SARS2-CoV RNA (Pearson correlation = 0.44, P = .02), crAssphage cDNA (Pearson correlation = 0.36, P = .02), and crAssphage DNA (Pearson correlation = 0.46, P = .002). We found good comparison between grab and 24-hour composite samples for detecting SARS-CoV-2 RNA from municipal wastewater treatment plants. Grab sampling is an efficient and cost-effective method to monitor for the presence of SARS-CoV-2 in the entire community.
Simultaneous inference of plate boundary stresses and mantle rheology using adjoints: large-scale 2-D models
Authors: Rudi Johann , Gurnis Michael , Stadler Georg
Published: June 2022

Plate motions are a primary surface constraint on plate and mantle dynamics and rheology, plate boundary stresses and the occurrence of great earthquakes. Within an optimization method, we use plate motion data to better constrain uncertain mantle parameters. For the optimization problem characterizing the maximum a posteriori rheological parameters we derive gradients using adjoints and expressions to approximate the posterior distributions for stresses within plate boundaries. We apply these methods to a 2-D cross section from the western to eastern Pacific, with temperature distributions and fault zone geometries developed primarily from seismic and plate motion data. We find that the best-fitting stress exponent, n, is about 2.8 and the yield stress about 100 MPa or less. The normal stress on the interplate fault zones is about 100 MPa and the shear stresses about 10 MPa or less.
Noise content assessment in GNSS coordinate time-series with autoregressive and heteroscedastic random errors
Authors: Wang Leyang , Wu Qiwen , Wu Fei , He Xiaoxing
Published: June 2022

Proper representation of the stochastic process of the Global Navigation Satellite System (GNSS) coordinate time-series lays a foundation for realistic velocities estimates and their uncertainties, as well as identifications of functional effects, generally called periodic/offset signals. Various noise models (e.g. autoregressive process) have been used to describe the stochastic process of GNSS data. A realistic stochastic model prefers proper consideration of individual error characteristics of observations. The usual autoregressive (AR) noise model assumes its white-noise components sharing the same constant variances, which might degrade the modelling accuracy of stochastic process. Through using a generalized autoregressive conditional heteroscedasticity (GARCH) process to quantify variance variation of the white-noise components, our current investigation has constituted an AR-GARCH noise model to realize the stochastic model and subsequent noise content assessment. This noise framework and its adjustment algorithm are further considered in the identifications of functional effects. For evaluating the performance of our current algorithm, 500 emulated real time-series were used, they consist of a linear trend, seasonal periodic signals, offsets, gaps (up to 10 per cent) and an AR-GARCH noise process. The algorithm's identification power for functional effects was investigated within a case study in the absence of periodic/offset signals. Furthermore, the algorithm's results were compared with the current state-of-the-art noise models (e.g. white plus flicker noise) using 15 real GNSS coordinate time-series. The results demonstrated that the presented stochastic model has been identified as a preferred noise model. Its model's algorithm can offer reliable noise content although sporadic unidentified periodic/offset signals are still masked in time-series. Moreover, the error volatility of white-noise components was identified via an autoregressive conditional heteroscedasticity Lagrange multiplier (ARCH LM) test and confirmed in the time-series.