bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of nonlinear behavior of viscoelastic damping in musical membranes using physics-informed self-organizing maps
Authors: Martínez Orellanos Cristhiam Fidel , Bader Rolf
Published: January 2025

This research offers a new analytical tool that unravels the nonlinear relation between the parameters of Viscoelastic Damping (VD) and the resulting frequency spectrum in musical membranes. Understanding how variations in VD parameters influence the resulting sounds is crucial for developing new tools for artistic expression and for designing musical instruments with distinct sound qualities. In the case of membranophones, the external damping is well understood, while the internal damping due to viscoelastic properties of materials remains unclear. In previous research, VD in musical membranes has been modeled using a Finite-Difference Time-Domain (FDTD) model. Nonetheless, analyzing the complex relationships between the large parameter space of the model and the nonlinear behavior of VD is a challenging task. This study addresses this analysis through physics-based machine learning. We employed a FDTD model of a viscoelastically damped membrane to create a physics-informed dataset, which we subsequently analyzed using Self-Organizing Maps (SOMs). Our findings reveal that the damping coefficient is the primary criterion when clustering the data. Furthermore, we found the internal structure of the cluster to depend on the rate of decay of the memory effect, i.e., the rate at which the energy introduced back into the system decreases. The study also demonstrates the benefits of using principal component analysis for the SOM initialization.
Quantum mode-locked Faraday laser
Authors: Gao Zhihong , Wang Zhiyang , Liu Zijie , Zhang Zhigang , Chen Jingbiao
Published: January 2025

We report an external-cavity mode-locked semiconductor laser that uses a Faraday atomic filter as a saturable absorber (SA), termed as the quantum mode-locked Faraday laser. The unique SA exhibits nonlinear transmission characteristics exclusively in the vicinity of the atomic quantum transition frequency, which narrows down the spectral bandwidth of the mode-locked pulses to the gigahertz level and results in a central wavelength of the mode-locked pulses corresponding to the 87Rb (F=2) component of the D2 quantum transition line. Simultaneously, influenced by the slow-light effect of rubidium-dispersive vapor in the SA configuration, the fundamental repetition rate of the mode locking can vary between 261 and 228 MHz. Pulse delay tests conducted outside the resonator provide conclusive evidence of a gigahertz-bandwidth slow light within the Faraday laser. The mode-locking technique presented here can be applied to pulsed light sources of other quantum transition lines by setting appropriate atomic filter parameters. In addition, this narrow-spectrum mode-locked laser, with a tunable repetition rate and a central wavelength corresponding to a quantum transition line, has potential applications in the fields of atomic precision spectroscopy and quantum precision metrology.
Enhanced performance and long-term stability of 2D photodetectors through hexagonal boron nitride encapsulation
Authors: Zhao Huijuan , Zhou Qiyuan , Wang Yufan , Wang Jiaxuan , Ding Huanlin , Li Shuhan , Guo Xiaohan , Wang Weiqi , Gao Li
Published: January 2025

Two-dimensional (2D) semiconductor materials, such as molybdenum disulfide (MoS2), demonstrate considerable potential for optoelectronic applications, largely due to their atomic thickness, tunable bandgap, and capacity for heterostructure integration. Nevertheless, the development of 2D photodetectors that can achieve high responsivity, a fast response time, and long-term stability remains a significant challenge. The present study is a systematic investigation of the effects of top and bottom encapsulation with hexagonal boron nitride (h-BN) on the performance and stability of 2D photodetectors. By employing a dry transfer process to fabricate a high-quality h-BN/MoS2/h-BN structure, we provide effective protection against environmental degradation. The encapsulated devices exhibited a responsivity increase of one to two orders of magnitude under 532 nm laser illumination, in comparison to those without encapsulation. Additionally, the rise and decay times were markedly reduced, by approximately two orders of magnitude, from 0.538 and 3.43 ms to 23.1 and 99.6 μs, respectively. Moreover, the devices demonstrated sustained performance over a 60-day storage period, with response times remaining faster than pre-encapsulation levels. This study highlights the potential of h-BN encapsulation for enhancing both the performance and stability of 2D photodetectors, advancing the development of more reliable optoelectronic devices.
Non-monotonic fluctuation of structural heterogeneity in metallic glass due to cyclic rapid heat treatment
Authors: Sun K. , Yuan X. D. , Zhang N. Z. , Jia Y. F. , Tseng J. C. , Kosiba K. , Jia Y. D. , Shuai C. , Pauly S. , Wang G.
Published: January 2025

Flash-annealing (FA) of metallic glasses (MGs) allows one to modulate their disordered structure. Here, we have flash-annealed a CuZr-based MG below the glass transition temperature at different cycles and generated MGs with various heterogeneous structures. We quantified the glassy structure via the relaxation enthalpy, ΔrelH, which did not significantly change for MGs flash-annealed at a low number of cycles. Their hardness monotonically reduced. However, when more than ten FA cycles were applied, ΔrelH, perceivably decreased, while corresponding hardness increased. High-energy x-ray diffraction analysis revealed that the medium-range ordering of the corresponding structure initially rose and then decreased with an increasing number of FA cycles. This structural change is accompanied by first a hardness decrease followed by an increase. Molecular dynamics simulations showed that throughout the shift from low to high cycles, the structural non-uniformity changed from being non-uniform to more uniform. Through a combination of experiments and simulations, we have shown the non-monotonic relationship between the structural heterogeneity of MGs and cyclic treatments, contributing to a better understanding of the relationship between structural control techniques, microstructure, and properties.
Suppression of autocorrelation artifacts in PS-OCT images based on spectral phase interpolation
Authors: Xu Songwen , Yang Di , Wang Weike , Chen Wenguang , Zhang Wei , Liang Yanmei
Published: January 2025

Polarization-maintaining (PM) fiber-based polarization-sensitive optical coherence tomography (PS-OCT) system has high stability and portability. However, PM fibers may introduce different kinds of artifacts. A spectral phase interpolation method is proposed to suppress the autocorrelation artifacts in this Letter, in which the reference phase is calculated based on each A-scan signal, and the calculated reference phase is used to perform phase interpolation in the original interference signal. Experimental results from the ex vivo porcine eye demonstrate that autocorrelation artifacts in PS-OCT images can be effectively eliminated and the original image information is perfectly recovered at artifacts.
Continuous and spontaneous directional droplet transport on bioinspired serial-wedge-shaped groove with wettability gradient
Authors: Hao Shaoqian , Zhao Zhigao , Xie Zhang , Li Zheng , Liu Junjie , Wu Fengmin , Kou Jianlong
Published: January 2025

We propose a serial-wedge-shaped groove with a wettability gradient to achieve continuous directional transport of droplets. Molecular dynamics simulations demonstrate that this design provides a sustained driving force and reduces energy barriers at junctions, facilitating continuous droplet motion. Moreover, higher temperatures and greater wettability gradients are shown to enhance the efficiency of continuous transport. Theoretical analysis further reveals that increasing surface hydrophobicity, width ratio, and droplet size can reduce energy barriers, thereby improving transport performance. These findings are expected to improve the understanding of continuous directional droplet transport and shed light on its manipulation.
Application of fluid dynamics methods in additive manufacturing
Authors: Wu Weiwei , Fu Jiangyuan , Zhang Jie , Gu Hai
Published: January 2025

With the rapid development of additive manufacturing (AM) technology, the application of fluid mechanics in this field has become increasingly important, as it can help deeply understand the process principle, improve the process parameters, and modify the device structures. The application of fluid mechanics methods in additive manufacturing processes is summarized according to different AM technology types. The different fluid dynamics methods can be used to simulate and investigate the flow process. The main methods or software include ANSYS Fluent, COMSOL, ANSYS CFX, OpenFOAM, and FLOW-3D. In the material extrusion process, by simulating the flow behavior of the material, the rate, stability, and temperature changes of the material during the extrusion process can be studied. In the powder bed melting process, fluid dynamics methods can help simulate the flow behavior of powder inside the powder bed, simulate the temperature distribution inside the powder bed, and predict the shape and size of the molten pool. In direct energy deposition processes, fluid dynamics simulation can be used to study the melting and solidification behavior of materials, as well as the temperature distribution within them, and to simulate the flow behavior of the molten pool, understanding the mixing and distribution of materials, etc. Fluid dynamics simulation can provide an in-depth understanding of fluid flow behavior in additive manufacturing processes and guide process optimization, material design, and component performance.
Anderson acceleration of Picard/Newton iteration based on grad-div stabilization for the Smagorinsky model
Authors: Zhang Qi , Huang Pengzhan
Published: January 2025

In this paper, we consider Anderson acceleration of one- and two-level Picard/Newton iterations based on the grad-div stabilization for the stationary Smagorinsky model at high Reynolds number. First, based on the grad-div stabilization, we propose the Anderson-accelerated Picard iteration, and then we introduce the Newton iteration at the end of iteration to accelerate convergence. Second, to reduce the computational cost, we consider a two-level algorithm, i.e., we use the previous Anderson acceleration of Picard/Newton iteration for the Smagorinsky model on a coarse mesh and then solve a generalized Stokes problem on fine mesh by the grad-div stabilized Picard iteration. The proposed algorithm not only improves convergence and reduces computational costs but also enhances the capability to simulate the fluid flow with high Reynolds number. Several numerical experiments have been conducted to demonstrate the numerical performance of the proposed algorithms.
Conductive filament formation in the failure of Hf0.5Zr0.5O2 ferroelectric capacitors
Authors: Webb Matthew , Chiang Tony , Lenox Megan K. , Gray Jordan , Ma Tao , Ihlefeld Jon F. , Heron John T.
Published: January 2025

Ferroelectric materials provide pathways to higher performance logic and memory technologies, with Hf0.5Zr0.5O2 being the most popular among them. However, critical challenges exist in understanding the material’s failure mechanisms to design long endurance lifetimes. In this work, dielectric failure due to repeated switching cycles, occurring through oxygen vacancy motion and leading to the formation of a conductive filament, is demonstrated. A field modified hopping barrier of ∼150–400 meV is observed, indicating a vacancy charge of 0.4–0.6e markedly different from the charge states predicted in the literature. After failure, the capacitor leakage current is high (∼25 mA) and constant with capacitor area, consistent with filament formation. Conductive atomic force microscopy measurements and field distribution simulations suggest a local failure mechanism consistent with filament formation along the boundary of the island capacitor due to an enhanced electric field.
Three-dimensional evolution and turbulent kinetic energy transport of tip vortex from an elliptical hydrofoil
Authors: Zhao Hang , Tu Han , Xu Ke-Wei , Luo Qian , Gao Qi , Zhang Guo-Ping , Cao Yan-Tao , Peng Xiao-Xing , Deng Jian , Shao Xue-Ming
Published: January 2025

A non-cavitating tip vortex generated by an elliptical hydrofoil is investigated utilizing tomographic particle image velocimetry (TPIV). Focus is placed on its three-dimensional evolution over a relatively large streamwise region, as well as the transport process of turbulent kinetic energy (TKE). Based on the variations in vortex structure and related vortex properties, three main stages of tip vortex evolution can be identified: formation stage, persistence stage, and decay stage. The boundary between the formation and persistence stages is the position where tip vortex cavitation (TVC) is more prone to incept, attributed to the rapid growth in vortex circulation and vortex-center axial velocity, along with high turbulent fluctuations. During the tip vortex evolution, its swirling momentum significantly influences the axial flow pattern, likely by altering the pressure gradient along the vortex path. TKE transport equation is employed to analyze the turbulent properties of the tip vortex. Flow near the hydrofoil tip is highly turbulent and unsteady, with the local TKE at an excessive level. The local high TKE tends to diffuse into surrounding flow rather than being concentrated within the tip vortex as it moves downstream. TKE is mainly produced on the suction side of hydrofoil, potentially due to local boundary-layer behaviors, and is subsequently transported into the vortex core. As the tip vortex propagates further downstream, the in-core TKE exhibits a decreasing trend, and a relaminarization process appears to occur in far wake region. The flow topology of the tip vortex is examined with the invariants of velocity gradient tensor, providing insights into the topological features during the vortex evolution.
Study on erosion wear and life prediction of double jet pump in fluid with high sand content
Authors: Tang Yang , Xu Jiaqing , Zhang Wudi , He Yufa , Wei Jianfei
Published: January 2025

The erosion characteristics of high sand flow fields are essential to the durability and performance of double jet pumps in oil and gas production. Using solid–liquid two-phase flow theory and an erosion model, this study evaluated how particle size, mass flow rate, and power fluid flow rate affect the erosion of double jet pumps. The findings reveal that erosion mainly occurs on the inner wall at the throat inlet, throat outlet, and diffuser inlet. With an increase in power fluid flow rate from 11 to 15 L/s, the maximum erosion rate at the throat's inlet cone escalates by a factor of 14.2. The throat inlet's service life is estimated at 275 hours. These insights provide valuable guidance for optimizing double jet pump design and application.
Electrohydrodynamic effects on the viscoelastic droplet deformation in shear flows
Authors: Zhao Jiachen , Dzanic Vedad , Wang Zhongzheng , Sauret Emilie
Published: January 2025

Droplet deformation under shear flows is widely observed in many practical applications, including droplet-based microfluidics and emulsion processing, whereby the droplet usually exhibits viscoelastic characteristics. It has been shown that the performance of these applications is significantly influenced by the size and shape of the resulting droplets. Therefore, the underlying performance is directly tied to the precision and efficiency of viscoelastic droplet control. Previous studies demonstrate that the electric field is a straightforward and efficient way of manipulating fluid flows. However, the effects of an electric field on the viscoelastic droplet deformation remain unexplored. To this aim, this work investigates the electrohydrodynamic (EHD) control of viscoelastic droplets under shear flows using a hybrid numerical framework coupling the lattice Boltzmann method and finite difference method. Extensive simulations are conducted under various electrical properties, such as conductivity ratio R, permittivity ratio S, and electric field strength CaE. Focus is placed on the quantitative analysis of the viscoelastic droplet morphological metrics including deformation D and inclination angle θ. Phase diagrams of D, θ, and combined D and θ in the plane of R–S are developed, where four regions can be identified based on different droplet behaviors under an electric field. The mechanism of this phenomenon is presented by analyzing the distribution of the electric field, electric charge, and electrical force at different regions. It is further observed that the electric field strength CaE amplifies these effects, either suppressing or promoting the droplet deformation and rotation. While viscoelastic effects are considered, they are found to play a subdominant role compared to EHD forces in controlling or modifying droplet morphology. This study provides insights into the electrohydrodynamic (EHD) effects on the dynamics of viscoelastic droplets in shear flow, contributing to the development of active control strategies for viscoelastic droplets in microfluidic applications, including drug delivery and food processing.
Resilience assessment of water supply and demand in the Yellow River Basin based on integrated optimisation weighting–improved grey-target model
Authors: Lv Hong , Zhao Xinlei , Yan Dengming , Shang Wenxiu , Zheng Xiaokang
Published: January 2025

Context As a result of the combined impacts of global climate change and intensive human activities, the water-resources supply–demand imbalance has become prominent, particularly in the Yellow River Basin. Aims This study aims to accurately assess the changes in resilience of water-resource supply and demand over the past few decades. Methods This study examines the resources, economy, society, and ecology of both the supply and demand aspects in assessing the resilience of water supply and demand. The composite evaluation model based on integrated optimisation weighting and an improved grey-target model was constructed. Key results Using the Yellow River Basin as an example, from 2011 to 2020, the resilience index of the water-resource supply–demand system (RIWRSS) in the Yellow River Basin increased significantly by 69.4%. Among the 12 indicators in the Yellow River Basin, the contribution proportion of the inhibiting factors decreased by 3.7%, whereas the contribution of the driving factors increased by 70.9%. Conclusions The present study has provided insights into evaluating the RIWRSS and highlighted resilience disparities between the supply and demand sides in the Yellow River Basin. Implications This study expects to provide evidence for the improvement of water-supply conditions of water resources in the Yellow River Basin.
Expansion of a conserved architecture drives the evolution of the primate visual cortex
Authors: Meyer Emily E. , Martynek Marcelina , Kastner Sabine , Livingstone Margaret S. , Arcaro Michael J.
Published: January 2025

Human brain evolution is marked by a disproportionate expansion of cortical regions associated with advanced perceptual and cognitive functions. While this expansion is often attributed to the emergence of novel specialized brain areas, modifications to evolutionarily conserved cortical regions also have been linked to species-specific behaviors. Distinguishing between these two evolutionary outcomes has been limited by the ability to make direct comparisons between species. Here, we addressed this limitation by examining the expansion of the human visual cortex relative to macaques using a common functional architecture: retinotopy. Our findings revealed that human visual cortex expansion is primarily driven by increases in the surface area of a visual map architecture present in macaques rather than an increase in the number of individual areas. This expansion was not uniform, with higher-order areas, particularly in the parietal cortex, exhibiting the largest growth. Comparisons between neonate and adult humans revealed that these relative areal size differences were already established at birth. A meta-analysis of neuroimaging studies indicated that the most expanded areas are associated with advanced cognitive functions beyond visual processing. These results suggest that human perceptual and cognitive adaptations may be rooted in the expansion of evolutionarily conserved cortical architecture, with modifications even in the sensory cortex contributing to the broader cognitive functions characteristic of human behavior.
Symmetry of traveling wave solutions for a Camassa–Holm type equation with higher-order nonlinearity
Authors: Cheng Wenguang , Lin Ji
Published: January 2025

We are concerned with a Camassa–Holm type equation with higher-order nonlinearity including some integrable peakon models such as the Camassa–Holm equation, the Degasperis–Procesi equation and the Novikov equation. We show that all the horizontal symmetric waves for this equation must be traveling waves. This extends the previous results for the Camassa–Holm and Novikov equations.
Introduction
Authors: Genenko Yuri , Rauh Hermann
Published: January 2025

This chapter presents milestones in studies of the superconductivity and gives a survey on world-wide research activities devoted to superconductor/paramagnet heterostructures, past and present.
Meissner state of thin superconductors in nonideal paramagnetic environments
Authors: Genenko Yuri , Rauh Hermann
Published: January 2025

In this Chapter, thin type-II superconductor strips, tubes or rings carrying a transport current in the Meissner state are considered in the presence of paramagnetic environments of finite magnetic permeability and finite size. Building on some of the model configurations for a thin superconductor strip analyzed in Chapter 3 and also introducing thin superconductors of tubular and annular shapes, the emphasis here is to test the quality of results obtained when idealized conditions prevail and, at the same time, identify regimes where new traits appear. Particularly, it is demonstrated that thin paramagnetic surroundings may also be used to effectively control current distributions in superconductor strips but the relative magnetic permeability needs to be large enough so as to compensate the small thickness of paramagnetic constituents
Meissner state and critical state of thin superconductors in arbitrary paramagnetic environments: finite-element simulations
Authors: Genenko Yuri , Rauh Hermann
Published: January 2025

Building on the results of Chapters 3 to 5 concerning both the flux-free Meissner state and the partially flux-filled critical state in model magnetic environments we take in this Chapter a step further towards investigations of superconductor/paramagnet heterostructures of practical relevance. To perform this, we call upon ANSYS and COMSOL, commercial finite-element programs for computing scalar, vector and tensor fields though not originally designed for modelling superconducting states, by exploiting magnetostatic-electrostatic analogues. The conditions of both an imposed transport current and an applied magnetic field are examined and the flux-free Meissner state as well as the partially flux-filled critical state taken into account. We calculate the hysteretic AC loss suffered by thin superconductor strips in various paramagnetic environments and the AC loss in magnetically shielded tubular wires in the presence of an applied magnetic field. Drastic reductions of the AC loss in some shielding configurations are predicted
RCV in Partisan and State Elections
Authors: Endersby James W , Towle Michael J
Published: January 2025

This chapter focuses on applications of preferential voting in partisan and state-level electoral contests. Primary elections for the selection of party nominees can be a useful environment for ranked choice voting (RCV) as there may be more than two viable candidates or factions. Several states adopted versions of RCV for primary elections during the Progressive Era. These early practices were repealed, sometimes due to fundamental assumptions about RCV and sometimes due to misinterpretation. Over time, many states served as laboratories of electoral democracy, adopting and testing a variety of electoral systems, including preferential voting. State judicial elections may also serve as an appropriate environment for RCV. Canada has extensive experience with RCV in past partisan provincial elections as well as in contemporary party leadership elections. RCV may have applications for party and state elections where polarization among voters is low and the number of alternatives competing exceeds two.
RCV in State and Federal Elections
Authors: Endersby James W , Towle Michael J
Published: January 2025

This chapter extends the discussion of ranked choice voting (RCV) to state elections generally, including detailed descriptions of its adoption in Maine and Alaska, and application of ranked choice methods for presidential elections. Potential applications of RCV are explored in these state and national election contexts. After a 2016 ballot initiative and lengthy adjudication, Maine began using RCV for party primaries and for federal elections in November 2018. Following a 2020 ballot proposition, Alaska adopted a top-four primary election with RCV in the general election. Both states instituted electoral change as a response to strong two-party polarization and extremism. RCV has also been suggested as a reform for the presidential nominating system, particularly for primaries with multiple candidates running, and even in the US general election for president. These possible applications in party primaries, national nominating conventions, and in relation to the Electoral College are explored in this chapter.
Evaluating RCV
Authors: Endersby James W , Towle Michael J
Published: January 2025

This chapter provides a discussion of some important features to take into consideration when contemplating ranked choice voting (RCV) and election reform. The goals and criticisms of RCV and plurality voting outlined earlier are reviewed in the context of actual election experience. Communities considering adoption (or rejection) of RCV or single transferable vote (STV) should take into account their intended goals and objectives as well as the drawbacks of RCV. Questions to pose and observations to consider provide a foundation to base an evaluation on actual electoral experience. There is no perfect electoral system. RCV and STV work well depending on the objectives of the reformers. On the other hand, preferential voting systems also impose burdens on voters and election administrators. RCV is not just an electoral system but a means for group decision-making. Alternative electoral systems or decision-making methods may also meet the goals suggested for RCV.
It's Only Human
Authors: Schulz Armin W
Published: January 2025

What makes humans cognitively unique—and why are they unique in these ways? These are interesting questions not just because we are humans, but also because we have an outsized influence on the planet as a whole. To answer them, this book begins by providing a clearer characterization of the nature of human cognitive uniqueness: it sets out and justifies an inventory of key features of distinctively human cognition. On this basis, the book assesses the major existing theories seeking to explain distinctively human thought from across the cognitive, social, and human sciences and argues that a new account is needed, one that bridges nativist and learning-based approaches. It then presents exactly such an account. At the heart of this account is a positive feedback loop that links evolved representations, forms of cultural learning, and technology. With the help of this feedback loop, key examples of uniquely human cognition can be explained: distinctively human mindreading, distinctively human moral cognition, and the distinctively human propensity for trade. The book concludes with an application of this interactionist theory of distinctively human cognition to various issues of contemporary importance: the relationship between distinctively human cognition and increasingly sophisticated artificial intelligence, the role of religion in human thought and action, and the relationship between extensive patent regimes and human innovation. In doing all this, the book takes a simultaneous methodological and explanatory approach: it shows how to best conduct the study of human cognitive uniqueness and actually engages in this study itself.
Introduction
Authors: Schulz Armin W
Published: January 2025

This chapter motivates the investigation of the evolution of distinctively human cognition: knowing more about how we think and act tells us something important about who we are, and it is useful for helping us make better decisions. The latter is especially important, given that we have an outsized influence on the planet. The chapter further clarifies the scope of the project and argues for the feasibility of this kind of evolutionary psychological investigation. It points out that the theory developed in the book is based on synthesizing work in many different fields—anthropology, psychology, economics, and philosophy, to name just a few—into a coherent overarching picture. While thus being a work of philosophy, it is not pure speculation: there is a difference between empirically grounded theorizing and fantasy. The chapter ends by providing an overview of the rest of the book.
Coup d’talk
Authors: Tendi Blessing-Miles
Published: January 2025

Zimbabwe’s 2017 coup has been variously described as ‘a popular, peaceful revolution’, ‘military assisted transition’, ‘non-coup-coup’, ‘gentle’ coup, ‘the politest coup in history’, the ‘softest military coup’, a ‘modern’ coup, and ‘a very Zimbabwean coup’. This chapter debunks the aforementioned representations of the coup as exceptional or different from other coups. The chapter argues that Zimbabwe’s 2017 coup shared comparable justifications and operational attributes with coups elsewhere in Africa. Exceptionalist representations of the 2017 Zimbabwean coup do not engage instructive literature on the history of coups in Africa—hence their mischaracterization of the military action. Finally, the examples of gendered coups discussed in Chapter 2 amply demonstrate that, regardless of time (cold war versus post-cold war) and geography (Zimbabwe versus ‘the average African experience’), an essential quality of coups is that they are gendered operations. Gender destabilizes neat categorization of cold -war-type coups and post-cold-war-type coups.
Smith-Purcell Radiation
Authors: Doucas George
Published: January 2025

Smith–Purcell radiation is the name given to the radiation produced when a charged particle beam, usually electrons, passes close to the surface of a metallic grating. The wavelength of the emitted radiation depends on the period of the grating and on the angle of observation. This makes this phenomenon a very useful tuneable source of radiation in the far-infrared (or THz) part of the spectrum, where tuneable sources are scarce. Moreover, a spectral analysis of the radiation can be used to reconstruct the time profile of the very short (picosecond or sub-picosecond) electron bunches that gave rise to this radiation. This is a parameter that is of interest to accelerator designers and users. The book is aimed primarily at experimentalists but starts with a relatively simple theoretical description of the origin of this radiation and then discusses its application either as a beam diagnostic tool or as a tuneable source of THz radiation. There is also a brief overview of other THz sources in order to allow the reader to assess the advantages of Smith–Purcell radiation.
Surface Current Theory
Authors: Doucas George
Published: January 2025

This chapter deals with the case of a single electron travelling above just one period of a perfectly conducting metallic grating. The charge density distribution induced on the surface is derived and discussed in some detail, and the emitted radiation is attributed to the acceleration of this surface charge distribution. The polarization of the emitted radiation is also discussed, together with the role of the grating width and the grating profile. There is a brief presentation of alternative theoretical descriptions and a comparison of the expected radiative yields in the case of highly relativistic electron beams, according to different theories.
Electron Beam Diagnostics
Authors: Doucas George
Published: January 2025

The chapter discusses various methods for determining the time profile of electron bunches of sub-picosecond duration, especially methods involving measurements in the frequency domain. Since this type of measurement gives the magnitude of the Fourier transform of the time profile but not its phase, it is necessary to deduce the missing phase. This can be done either through the use of iterative algorithms or by applying the Kramers–Kronig method in order to recover the minimal phase. This is described in some detail, together with examples where the minimal phase is adequate and others where other contributions to the phase (Blaschke phases) are necessary for an accurate reconstruction.
Beam Diagnostics with Smith–Purcell Radiation
Authors: Doucas George
Published: January 2025

The use of multiple gratings allows simultaneous sampling of the emitted radiation at a number of wavelengths and thus offers the prospect of determining the bunch profile in a single shot. This chapter reviews the criteria for deciding on the optimal number of sampling points and the methods of suppressing the background (i.e. non-Smith–Purcell) radiation through the use of filters and/or through the exploitation of the polarization properties of Smith–Purcell. The possible role of the grating itself as a source of blackbody background radiation is also assessed. Included in the chapter is an examples of a reconstructed time profile of a bunch with sub-picosecond full width at half maximum. There is also a brief discussion of the use of SP radiation as a monitor of the microbunch spacing in a train of microbunches.
Appendix
Authors: Doucas George
Published: January 2025

The Appendix presents a brief overview of two instruments that are essential for all work in the far-infrared (THz) part of the spectrum: detectors and filters. The detectors are assessed according to their spectral range, their ability to discriminate against noise (noise equivalent power (NEP)) and their responsivity. The filters relevant in this wavelength band are wire mesh filters, waveguide array plates (WAP), and polyethylene transmission gratings. This chapter includes typical transmission curves for these three types of filter. It also emphasizes the importance of maximizing the light collection efficiency of the emitted Smith–Purcell radiation through the use of Winston cones.
Early detection and management of hearing loss to reduce dementia risk in older adults with mild cognitive impairment: findings from the treating auditory impairment and cognition trial (TACT)
Authors: Yu Ruan-Ching , Pavlou Menelaos , Schilder Anne G M , Bamiou Doris-Eva , Lewis Glyn , Lin Frank Robert , Livingston Gill , Proctor Danielle , Omar Rumana , Costafreda Sergi G
Published: January 2025

Background

Age-related hearing loss and mild cognitive impairment (MCI) independently increase dementia risk. The Ageing and Cognitive Health Evaluation in Elders randomised controlled trial (RCT) found hearing aids reduce cognitive decline in high-risk older adults with poor hearing.

Methods

This pilot RCT in London memory clinics randomised people with MCI (aged ≥55, untreated hearing loss defined as Pure Tone Average 0.5–4 KHz between 25–70 dB) into two groups. The intervention group received 4 sessions of hearing aid fitting and support. The control group received healthy ageing education and a GP letter recommending audiological referral. Both were followed for 6 months. Primary outcomes were recruitment (feasibility target: 50%; 95% CI: 39%–61%) and retention (feasibility target: 80%; 95% CI: 71%–89%); intervention completion (≥2 visits) and hearing aid use (acceptability target: 80%; 95% CI: 71%–89%) for the intervention group and 50% difference between arms (95% CI: 31%–69%). Secondary outcomes included hearing aid fitting, cognition and other measures.

Results

From October 2018 to March 2020, 58 participants were recruited (29 per group, 95% [86%–99%]). Twenty-four participants were fitted with hearing aids in the intervention arm, and 6 in the control arm (difference: 62% [42%–82%]). At 6 months, retention was 81% [69%–90%]. Hearing intervention completion (≥2 visits) was achieved by 24 (83%). Daily hearing aid use was reported by 18 (75%) intervention versus 5 (22%) control participants, a difference of 53% [29%–77%].

Conclusion

Randomisation of people with MCI to a personalised hearing intervention versus control is feasible. These findings support proceeding to a fully-powered multicentre RCT.
A framework of multi-view machine learning for biological spectral unmixing of fluorophores with overlapping excitation and emission spectra
Authors: Wang Ruogu , Feng Yunlong , Valm Alex M
Published: January 2025

The accuracy of assigning fluorophore identity and abundance, known as spectral unmixing, in biological fluorescence microscopy images remains a significant challenge due to the substantial overlap in emission spectra among fluorophores. In traditional laser scanning confocal spectral microscopy, fluorophore information is acquired by recording emission spectra with a single combination of discrete excitation wavelengths. However, organic fluorophores possess characteristic excitation spectra in addition to their unique emission spectral signatures. In this paper, we propose a generalized multi-view machine learning approach that leverages both excitation and emission spectra to significantly improve the accuracy in differentiating multiple highly overlapping fluorophores in a single image. By recording emission spectra of the same field with multiple combinations of excitation wavelengths, we obtain data representing different views of the underlying fluorophore distribution in the sample. We then propose a multi-view machine learning framework that allows for the flexible incorporation of noise information and abundance constraints, enabling the extraction of spectral signatures from reference images and efficient recovery of corresponding abundances in unknown mixed images. Numerical experiments on simulated image data demonstrate the method’s efficacy in improving accuracy, allowing for the discrimination of 100 fluorophores with highly overlapping spectra. Furthermore, validation on images of mixtures of fluorescently labeled Escherichia coli highlights the power of the proposed multi-view strategy in discriminating fluorophores with spectral overlap in real biological images.
Narrating the Consequences of Conflict: Death, Survival and the ‘Autobiographical Turn’ in the Criminology of War
Authors: Hearty Kevin
Published: January 2025

Locating itself within narrative criminological scholarship and the criminology of war literature, this article critically examines how the themes of death and survival are understood and represented in the memoirs of former Irish Republican Army (IRA) members. Building on the recent ‘autobiographical turn’ in the criminology of war, it identifies how death is storied from perspectives that reflect the nature of armed conflict, capture human loss, and criticize the leadership. Similarly, it shows how survival is storied as having outlived the conflict, living a meaningful post-conflict life, and addressing the legacy of conflict. It is concluded that these memoirs are a valuable dataset that amplify counter-discourses based on the lived experience of former combatants from non-state armed groups.
Artificial intelligence models using F-wave responses predict amyotrophic lateral sclerosis
Authors: Martinez-Thompson Jennifer M , Mazurek Kevin A , Parra Cantu Carolina , Naddaf Elie , Gogineni Venkatsampath , Botha Hugo , Jones David T , Laughlin Ruple S , Barnard Leland , Staff Nathan P
Published: January 2025

Nerve conduction F-wave studies contain critical information about subclinical motor dysfunction which may be used to diagnose patients with amyotrophic lateral sclerosis (ALS). However, F-wave responses are highly variable in morphology, making waveform interpretation challenging. Artificial Intelligence techniques can extract time-frequency features to provide new insights into ALS diagnosis and prognosis.

A retrospective analysis was performed on F-wave responses from 46,802 patients. Discrete wavelet transforms were applied to time-series waveform responses after stimulating ulnar, median, fibular, and tibial nerves. Wavelet coefficient statistics, onset age, sex, and BMI were features for training a Gradient Boosting Machine model on 40,095 (5,329 diagnosed with motor neuron disease). Model performance was tested on responses from 689 ALS patients meeting Gold Coast criteria and 689 age- and sex-matched controls. An exploratory analysis examined model performance on cohorts of patients with inclusion body myositis (IBM), cervical radiculopathy, lumbar radiculopathy, or peripheral neuropathy which can mimic ALS symptoms. Factors affecting survival were estimated through cox proportional hazards regression.

The model trained using wavelet-features on the full waveform had 90% recall, 87% precision, and 88% accuracy. Similar model performance was measured using features only from the M-Wave or F-Wave. Classification probabilities for ALS patients were statistically different from the diagnoses mimicking ALS symptoms (p<0.001, ANOVA, Tukey’s post-hoc), Higher model classification probabilities of ALS, older age at onset, and family history of ALS alone or with frontotemporal dementia were factors decreasing survival. Longer diagnostic delay and upper limb onset site were factors increasing survival. Model scores two standard deviations below the mean had 4 months increased survival (two standard deviations below had 3 months decreased survival).

Artificial intelligence techniques extracted important information from F-wave responses to estimate a patient’s likelihood of ALS and their survival risks. Although the model can make predictions at specific decision threshold as presented here, the true strength of such a model lies in its ability to provide probabilities about whether a patient is likely to have ALS compared to other mimicking diagnoses such as IBM, cervical or lumbar radiculopathy, or peripheral neuropathy. These probabilities provide clinicians with additional information they can use to make the final diagnosis with greater confidence and precision. Integrating such a model into the clinical workflow could help clinicians diagnose ALS sooner and manage treatment based on estimated survival, which may improve outcomes and patients’ quality of life.
Voluntary and involuntary motor behaviours in the varieties of religious experience
Authors: Ganos Christos , Ferguson Michael , Gray Kurt , Lees Andrew , Bhatia Kailash P , Haggard Patrick
Published: January 2025

Religion is a widespread feature of human life. Religions typically include both distinctive varieties of experience, and also a set of foundational beliefs. An additional, but often overlooked, part of many religions is their expression through specific actions, which we here designate religious motor behaviours. Here we describe these religious motor behaviours, and offer a taxonomy based on the conceptual schemes of movement neuroscience and neurology. Thus, religious rituals include both behaviours characterised by decreased motor output (e.g., ritualistic silence), and behaviours characterised by increased motor output (e.g., ritual dances). Neurology often also distinguishes between movements that are experienced as voluntary or involuntary. We show that this same distinction can also apply to religious experiences, since these may be characterised either by a heightened sense of personal control, or a sense of being controlled by an external, divine source. We then use these conceptual structures of movement neuroscience to investigate examples from a wide range of religious contexts. We thereby categorise religious motor behaviours into different classes, focussing on specific examples: repetitive ritual actions; motor behaviours where the experience of volition is altered, such as automatisms; and possession-like states. We suggest that a scientific approach to these behaviours should include their predominant phenomenological presentation, the accompanying subjective experience of volition, and the underlying neurocognitive mechanisms. This investigation shows rich parallels between religious motor behaviours and motor behaviours observed in neurological disorders, including those that present with functional neurological symptoms. Our approach does not and should not pathologise religious motor behaviours, but rather draws attention to a rich set of non-clinical motor phenomena that highlight important social, cultural and psychological elements of human movement control. Movement neuroscience and religious activity have unexplored overlaps and can usefully learn from each other.
Wild bees show local spatial and temporal dynamics in southeastern US blueberry farmscapes
Authors: Rezende Sarah M , Pennisi Svoboda V , Gariepy Tara , Querejeta Marina , Ulyshen Michael , Schmidt Jason M
Published: January 2025

Wild bee communities are the target of various conservation and ecological restoration programs. Strategic conservation can influence bee communities visiting fields and help mitigate pollinator limitations in fruit production. However, planning compatible conservation strategies and gauging their effectiveness requires understanding how local communities vary across space and time in crops and adjacent semi-natural areas. Here, we assessed the spatiotemporal changes in the composition of wild bee communities in blueberry fields and adjacent forests. In partnership with commercial farms in southeast Georgia, USA, we deployed blue vane traps at the interior and edge of blueberry fields and within adjacent forests of 8 fields, from March to October over 2 yr. We identified 72 wild bee species across 26 genera. The most common were Melissodes communis (Cresson, Hymenoptera: Apidae), Bombus bimaculatus (Cresson, Apidae), Melissodes bimaculatus (Lepeletier), Ceratina floridana (Mitchell, Apidae), Lasioglossum pectorale (Smith, Halictidae), and Lasioglossum nymphale (Smith), which accounted for nearly 60% of the wild bees caught. Bee diversity and richness fluctuated over time, with peaks in all 3 habitat types occurring after the blueberry blooming. Bee abundance in the adjacent forest was relatively constant throughout the season, while in the field interior and edge assemblages, abundance peaked between May and June. We observed dissimilarity in species composition related to month and field location. This difference was explained by fluctuation in the identity and relative abundance of the most abundant species. Together, our study advances foundational knowledge of wild bee community dynamics and species identity in blueberry fields which will help inform and prioritize conservation practices.