bluuebunny/crossref_metadata_2025 huggingface dataset:
Emergence of cooperative particle dynamics in quasi-two-dimensional glass-forming colloidal suspensions
Authors: Yun Jinseong , Chun Byoungjin , Jung Hyun Wook , Hyun Jae Chun
Published: January 2024

As the concentration of particles in a glass-forming liquid increases, their dynamics slow down significantly, displaying solid-like behavior. This behavior is primarily attributed to cage formation, wherein particles are trapped by their neighbors. However, the particle dynamics near the onset of cage formation remain limitedly understood. In this study, we systematically investigated the dynamics of particles in a quasi-two-dimensional glass-forming colloidal suspension using a particle-level simulation. We utilized the “raspberry” model with a hybrid simulation approach. This approach combined lattice Boltzmann and molecular dynamics schemes for elucidating hydrodynamically interacting densely packed colloidal suspensions, with an area packing fraction of 0.45 ≤ ϕ ≤ 0.85. At a quiescent condition where particles underwent thermal motion, the string-like movements of particles became pronounced as ϕ increased. The hydrodynamic interactions between these particles were effective up to ϕ = 0.6, wherein the string-like motion first appeared, but were mostly screened at higher ϕ values. Furthermore, we extended our analysis by imposing a small probing force, locally applied to the suspensions. The most significant response occurred at ϕ = 0.6, where particles moved cooperatively during the cage formation process, similar to the experimental results of Li et al. [Nature 587, 225–229 (2020)]. By linking particle behaviors in two different scenarios, our study enhances our understanding of the emergence of highly cooperative particle movement and sheds light on the role of hydrodynamic interactions in glass-forming colloidal suspensions.
Velocity modulation on the linear instability of liquid jets in ambient gas
Authors: Qiao Ran , Zhao Chengxi , Ding Zhaodong , Mu Kai , Si Ting
Published: January 2024

The linear instability analysis of liquid jets with periodic velocity modulation in the ambient gas is carried out. Utilizing the viscous potential theory and the Floquet theory, an analytical dispersion relation for the perturbation growth can be obtained. Due to the parametric resonance caused by velocity modulation, the oscillatory Kelvin–Helmholtz instability (OKHI) can be triggered in the short-wavelength region, leading to the competition between the OKHI and the intrinsic Rayleigh–Plateau and Kelvin–Helmholtz instability (RP-KHI). The parametric study shows that the increase in the velocity oscillation amplitude can enhance the jet instability and lead to the transition of the instability mechanism from the RP-KHI to the OKHI. The velocity oscillation frequency mainly affects the growth of the OKHI. Specifically, the maximum growth rates of perturbation vary with the oscillation frequency at moderate frequencies due to the competition between the RP-KHI and the OKHI, whereas they converge to constant values as the frequency either increases or decreases continuously. The increase in the Weber number promotes the RP-KHI and the OKHI simultaneously, and the jet breakup is dominated by the axisymmetric perturbation of the RP-KHI consistently. The increase in the Reynolds number enhances the jet instability, but hardly affects unstable wavenumber regions. By comparing the maximum growth rates of axisymmetric and non-axisymmetric perturbations, the predominant mode of the jet instability can be identified. Considering variations in the velocity oscillation amplitude and frequency, the transition between the RP-KHI and the OKHI can be predicted by a phase diagram.
Growth kinetics and morphology characterization of binary polymeric fluid under random photo-illumination
Authors: Singh Ashish Kumar , Chauhan Avinash , Singh Awaneesh
Published: January 2024

We present a comprehensive study using dissipative particle dynamics simulations to investigate phase separation kinetics (PSK) in three-dimensional (3d) polymeric fluids under random photo-illumination. We consider two scenarios: polymer blends with active radicals at one end of each immiscible chain and block copolymer (BCP) melts with photosensitive bonds linking incompatible blocks. The phase separation (PS) is induced by temperature quench of the initial homogeneously mixed system. Simultaneously, the system experiences random photo-illumination, simulated by two concurrent random events: (a) the recombination of active radicals in polymer blends and (b) the breaking of photosensitive bonds in BCP chains. Variations in the bond-breaking probability, Pb, mimic the change in light intensity. The length scale follows power law growth, R(t) ∼ tϕ, where ϕ represents the growth exponent. Increasing Pb results in a gradual transition in growth kinetics from micro-PS to macro-PS, accompanied by corresponding transition probabilities for both systems. Micro-PSK dominates the evolution process at low Pb values. The scaling functions exhibit data overlap for most scaled distances, indicating the statistical self-similarity of evolving patterns. Our study enhances the understanding of PSK in polymeric fluids, revealing the impact of photosensitive bonds and active radicals. Furthermore, it suggests the potential for designing novel polymeric materials with desired properties.
Computational analysis of the fluid–structure interactions of a synthetic badminton shuttlecock
Authors: Zala Darshankumar , Dechiraju Harish , Mittal Sanjay
Published: January 2024

Fluid–structure interactions of a synthetic badminton shuttlecock at various flight speeds are investigated computationally. The cork of the shuttlecock is held fixed and its skirt is free to deform. The cross-sectional area of the skirt decreases with an increase in flight speed leading to a significant reduction in the drag compared to that for an undeformed shuttlecock. Four regimes of deformation, with an increase in speed, are identified. The deformation is steady and axisymmetric in regime 1. Beyond a certain speed, which is referred to as “buckling speed,” the deformation is in regime 2. The skirt assumes a non-axisymmetric shape with a significant increase in its rate of deformation with speed. It undergoes vibration in regime 3. The amplitude of vibration increases with increased speed. In regime 4, the vibrations are modulated atop a lower frequency wave that travels circumferentially along the skirt. Compared to a rigid shuttlecock at the same flow speed, the streamwise vortex structures inside the skirt are weaker in a deformed shuttlecock. The decrease in the drag coefficient with an increase in speed is due to a decrease in the cross-sectional area of the skirt as well as a reduction in the entrainment of the flow through the gaps in the skirt area. The computational results are in good agreement with the available experimental measurements. The effect of the elastic modulus of the material and various structural reinforcements is studied.
The interplay between electron tunneling and Auger emission in a single quantum emitter weakly coupled to an electron reservoir
Authors: Zöllner M. , Mannel H. , Rimek F. , Maib B. , Schwarz N. , Wieck A. D. , Ludwig A. , Lorke A. , Geller M.
Published: January 2024

In quantum dots (QDs), the Auger recombination is a non-radiative scattering process in which the optical transition energy of a charged exciton (trion) is transferred to an additional electron leaving the dot. Electron tunneling from a reservoir is the competing process that replenishes the QD with an electron again. Here, we study the dependence of the tunneling and Auger recombination rate on the applied electric field using high-resolution time-resolved resonance fluorescence (RF) measurements. With the given p–i–n diode structure and a tunnel barrier between the electron reservoir and the QD of 45 nm, we measured a tunneling rate into the QD in the order of ms−1. This rate shows a strong decrease by almost an order of magnitude for decreasing electric field, while the Auger emission rate decreases by a factor of five in the same voltage range. Furthermore, we study in detail the influence of the Auger recombination and the tunneling rate from the charge reservoir into the QD on the intensity and linewidth of the trion transition. In addition to the well-known quenching of the trion transition, we observe in our time-resolved RF measurements a strong influence of the tunneling rate on the observed linewidth. The steady-state RF measurement yields a broadened trion transition of about 1.5 GHz for an Auger emission rate of the same order as the electron tunneling rate. In a non-equilibrium measurement, the Auger recombination can be suppressed, and a more than four times smaller linewidth of 340 MHz (1.4 μeV) is measured.
Electrokinetic behavior of an individual liquid metal droplet in a rotating electric field
Authors: Song Chunlei , Tao Ye , Liu Weiyu , Chen Yicheng , Yang Ruizhe , Guo Wenshang , Li Biao , Ren Yukun
Published: January 2024

The interfacial tension gradient forms tangential stress that drives fluid flow at a liquid–liquid interface, known as the Marangoni convection. In this study, we report on the electrocapillary-driven Marangoni flow at the polarizable interface between a gallium-based liquid metal droplet (LMD) and electrolytes, activated by the rotating electric field. When the electric field frequency exceeds 50 Hz, the amplitude of the oscillatory movement of LMD decays to zero, resulting in a stationary droplet. Utilizing micrometer-resolution particle image velocimetry (micro-PIV), we investigate the flow patterns around the LMD in detail. The visualized flow fields reveal two distinct flow patterns in the surrounding fluid at the central cross section of LMD, which vary with changes in frequency: normal flow (50–200 Hz) and tangential flow (300–1000 Hz). To reveal this flow mechanism, we first analyzed the fluid configuration in a linear electric field. Subsequently, we employ the stream functions to theoretically derive the slip velocity of the Marangoni flow in a rotating electric field. By combining this with the numerical simulations, we arrive at the following conclusions: At high frequencies (f≥50 Hz), the time-averaged part of the interfacial tension gradient dominates the in-phase Marangoni flow, leading to normal flow; while the frequency increases (f≥300 Hz), the electrorotation due to the out-of-phase charging accounts for the transformation of the flow pattern. Our work systematically studied the Marangoni flow under linear and rotating electric fields, which is vital in electrokinetic flows and of fundamental interest for the fluid dynamics society.
Experimental and numerical investigation on the unsteady interaction in longitudinal stage separation for parallel-staged two-body configuration
Authors: Wang Yue , Wang Yunpeng , Jiang Zonglin
Published: January 2024

Hypersonic stage separation is a significant process, probably involving complex aerodynamic interaction, which determines the survival of two-stage-to-orbit (TSTO) vehicles. The longitudinal stage separation (LSS) scheme is proposed to improve the safety of the parallel-staged TSTO vehicle, where a small interstage gap may result in weak interference. Therefore, an experimental and numerical study of LSS for the parallel-staged TSTO vehicle at Mach 7 with different angles of attack (AoA) is carried out. The dynamic interaction, including variations in the shock structure, wall pressure distribution, and unsteady aerodynamics, is investigated by testing and numerical simulation. The LSS experiments for the TSTO vehicle were performed using a high-speed pneumatic ejection launch system in the JF-12 shock tunnel, and the method was developed using high-speed visualization and image processing techniques to capture the separating trajectory. The numerical simulations were carried out using the overset grid method and solving the Navier–Stokes equations coupled with the rigid body dynamics equations to obtain the laminar flows over the TSTO vehicle during LSS. The qualitative and quantitative comparison of the test and numerical results showed good agreement in terms of aerodynamic performance, flowfield pattern, wall pressure, and separation trajectory. They show that the small interstage gap of the LSS leads to weak type I and VI shock–shock interactions, with short-duration weak shock reflection at a higher AoA. Furthermore, no shock reflection or interstage gap is observed at lower AoA. Moreover, no stage recontact is observed, and the safety and feasibility of LSS for parallel-staged TSTO vehicles are demonstrated.
Evolution of weakly unstable oblique detonation in disturbed inflow
Authors: Niu Shuzhen , Yang Pengfei , Xi Xuechen , Li Zhenzhen , Teng Honghui
Published: January 2024

The surface instability of oblique detonation waves (ODWs) without perturbations has been extensively investigated, yet the impact of external perturbations remains under-explored. Utilizing reactive Euler equations coupled with a two-step induction-exothermic reaction model, this study conducts a numerical examination of the evolution of unstable ODW surfaces subjected to a continuous sinusoidal density/temperature perturbation inflow. The results show that, without inflow perturbations, the ODW can evolve into triple points in the downstream due to detonation instability, similar to previous work. However, a small continuous perturbation can induce a significant forward movement of the ODW unstable position. Surprisingly, as the perturbation magnitude increases, the changes in the unstable position become progressively less pronounced. By increasing the perturbation frequency, the oscillation amplitude first increases, but a decreasing period/stage occurs with a modest frequency. To investigate the response of ODW to the increase in perturbation, the frequency characteristics and numerical smoked cells of detonation surfaces are examined and analyzed using Fast Fourier Transformation. The power spectral density indicates the presence of two distinct oscillation modes within oblique detonation. Low-frequency, small-amplitude perturbations serve to amplify the instability of the detonation, and more irregular oscillations could be observed. Conversely, high-frequency, large-amplitude perturbations suppress the development of small-scale waves on the detonation wavefront and lead to a relative regular oscillation, indicating that the wavefront pressure oscillations are entirely determined by inflow perturbations and become predictable. These findings have significant implications for the control of intrinsically unstable ODWs, providing valuable insights into the regulation of ODW dynamics.
Research on the characteristics of two-phase flow-induced noise in the cavitation dynamics of electronic expansion valves
Authors: Wang Junyu , Song Yongxing , Liu Jingting , Zhang Linhua
Published: January 2024

Electronic expansion valves are widely used in refrigeration systems. However, the two-phase flow-induced noise is often produced during operation. In this paper, the two-phase flow-induced noise characteristics of electronic expansion valves are investigated by means of a combination of numerical calculations and experimental studies. The numerical results show that the noise distribution in the flow field is closely related to the valve opening. As the valve opening increases, the noise in the flow field begins to develop in the downstream region. The experimental results showed a gradual increase in the refrigerant flow rate of the experimental system as the valve opening was increased from 60 to 200 pulses (tested at 10-pulse intervals). The flow-induced noise increases first and then decreases and then increases. With the increase in valve opening, the cavitation phenomenon after valve throttling becomes more and more serious. By processing the noise signal, it is found that the flow-induced noise is distributed in wide frequency. When the valve opening is 60–100 pulse, the noise is mainly concentrated in 10–20 kHz. When the valve opening is 110–150 pulses, the noise concentrated in the high band gradually spreads to the low band. When the valve opening is 160–200 pulses, the noise at low frequency and high frequency increases significantly with the increase in valve opening. After adding a groove structure on the valve core, the noise of the electronic expansion valve decreased by 1.75 dB.
Capturing non-equilibrium effects in cylindrical Couette flow problem using the Extended Onsager-13 moment equations
Authors: Yadav Upendra , Agrawal Amit
Published: January 2024

In the present work, cylindrical Couette flow is analyzed using the recently derived third-order accurate 13-moment transport equations by transforming them into cylindrical coordinates. Assuming the Mach number and normalized temperature difference between the cylinders to be relatively small, closed-form expressions for all relevant quantities, velocity, pressure, temperature, heat flux, and stresses, are obtained from the semi-linearized form of the equations. These closed-form expressions from the present study have been validated against the corresponding linearized Grad 13 moment (G13) equation solutions. It is further demonstrated that contrary to the G13 equations, the pressure in the cylinder annulus is not constant, while the temperature depends upon the magnitude of viscous heating apart from non-isothermal boundary conditions. The coupling among velocity, temperature, heat flux, and stress and its effect on the variation of various physical quantities across the annulus has been discussed. The obtained analytical solution shows that the equations correctly capture most known non-equilibrium effects, such as the presence of a Knudsen layer, non-Newtonian stresses, and non-Fourier heat flux for Knudsen numbers falling well into the transition regime through a quantitative agreement with direct simulation Monte Carlo data, G13, and regularized 13-moment equations. The presence of non-zero radial and tangential heat fluxes, even when both the cylinders are at the same temperature, has been observed. The analysis helps us to demonstrate the ability of the recently derived equations in accurately solving complex rarefied flow problems. Moreover, understanding of higher-order rarefaction effects should greatly improve with the availability of closed-form analytical expressions of all physical quantities obtained here.
Hydrodynamics of particle-free and particle-laden laminar flows in sharply bent channels
Authors: Sharma Abhishek , Singh Gaurav , Lakkaraju Rajaram , Atta Arnab
Published: January 2024

Sharp bends alter the hydrodynamics of particle-free and particle-laden fluid flow and induce additional losses in the form of recirculation zones that can be viewed as increase in entropy of the system. Here, we use a thermodynamic relation that accounts for the dissipation rate to delineate the contribution of recirculation zones and obstruction in the fluid flow due to channel bending. Results show that secondary flow formation dominates over obstruction effects at lower Reynolds number and becomes weaker at higher Reynolds number for both particle-free and neutrally buoyant particles. However, for inertial particles, obstructive forces prevail over the dissipative forces.
Coexistence of different mechanisms underlying the dynamics of supersonic turbulent flow over a compression ramp
Authors: Fan Jianhui , Uy Ken Chun Kit , Hao Jiaao , Wen Chih-Yung
Published: January 2024

Supersonic turbulent flow over a compression ramp is studied using wall-resolved large eddy simulation with a freestream Mach number of 2.95 and a Reynolds number [based on δ0: the thickness of incoming turbulent boundary layer (TBL)] of 63 560. The unsteady dynamics of the present shock wave/turbulent boundary layer interaction (STBLI) flow are investigated by using dynamic mode decomposition techniques, linear and nonlinear disambiguation optimization, local stability analysis (LSA), and global stability analysis (GSA). By analyzing the dynamic system for the STBLI flow, three dynamically important modes with characteristic spanwise wavelengths of 2δ0, 3δ0, and 6δ0 are captured. The 2δ0 mode approximates the spanwise scale of the Görtler-like vortices and Görtler mode of LSA, suggesting the presence of Görtler instability, which is believed to be related to the unsteady motion of streaks downstream of reattachment in the flow. The features of the 3δ0 mode are also observed in large-scale motions of the incoming TBL, implying the existence of a convective mechanism that is excited and maintained by such motions. Additionally, the GSA results show the most unstable mode features a spanwise wavelength of around 6δ0, indicating the existence of global instability that is believed to be related to the oscillating motion of separation shock. The coexistence of these three mechanisms is confirmed. Discussions on the above findings provide an interpretation for low-frequency unsteadiness that the unsteadiness of surface streaks results from the combined effects of the Görtler instability near flow reattachment and the convection of large-scale motions in the incoming boundary layer, while the low-frequency shock motion may be related to a global mode driven by upstream disturbances.
Microfluidic pressure-driven flow of a pair of deformable particles suspended in Newtonian and viscoelastic media: A numerical study
Authors: Esposito Giancarlo , D'Avino Gaetano , Villone Massimiliano Maria
Published: January 2024

The manipulation and control of microparticles through non-intrusive methods is pivotal in biomedical applications such as cell sorting and cell focusing. Although several experimental and numerical studies have been dedicated to single suspended particles or clusters of rigid spheres, analogous cases with deformable particles have not been as thoroughly studied, especially when the suspending liquid exhibits relevant viscoelastic properties. With the goal of expanding the current knowledge concerning these systems, we perform a computational study on the hydrodynamic interactions between two neutrally buoyant initially spherical elastic particles suspended in Newtonian and shear-thinning viscoelastic matrices subjected to pressure-driven flow in a cylindrical microchannel. Due to the well-known focusing mechanism induced by both particle deformability and fluid elasticity, the two particles are assumed to flow at the axis of the tube. The rheological behavior of the viscoelastic continuous phase is modeled via the Giesekus constitutive equation, whereas the particles are assumed to behave as neo-Hookean solids. The problem is tackled by employing a mixed finite-element method. The effects of particle deformability, fluid elasticity, confinement ratio, and initial interparticle separation distance on the pair dynamics are investigated. The main outcome of this study is a quantitative indication of the flow conditions and spatial configurations (initial distances) under which the particles will spontaneously form organized structures. Such results are helpful to design efficient microfluidic devices with the aim of promoting particle ordering.
Enhancing the convective heat transfer in vertical and horizontal rectangular enclosures using nanofluids: The crucial role of aspect ratio
Authors: El hadoui Bilal , Kaddiri Mourad
Published: January 2024

This study extensively examines double-diffusive natural convection of a water nanofluid containing Al2O3 nanoparticles in both horizontal and vertical rectangular enclosures subjected to uniform thermal and solutal fluxes along the horizontal direction. The key contribution of this research is to emphasize the significance of aspect ratio as a critical factor for enhancing heat transfer. Neglecting this factor could have substantial implications for the advancement and practical application of nanotechnology in heat transfer. The study also examines the impact of other relevant parameters namely nanoparticle concentration, thermal Rayleigh number, and three distinct models to calculate effective viscosity and thermal conductivity. A comparison among these models highlights a notable disparity between models based on experimental data (model II and III) and that based on theoretical assumptions (model I). It was revealed that the thermal Rayleigh number manifests a notable impact on both heat and mass transfers, especially for horizontal enclosures, and an augmentation in the aspect ratio improves the convective heat and mass transfers. However, for lower Rayleigh numbers, the aspect ratio effect diminishes. The incorporation of nanoparticles might deteriorate up to 21% or enhance up to 12% heat transfer according to the dominant transfer mode, we obtain the enhancement in conduction and deterioration in convection. Model I gives higher Nusselt and Sherwood numbers, followed by models II and III, but model I showed a peculiar behavior compared to models II and III. A critical aspect ratio is identified which defines the regions where nanofluid enhances heat transfer compared with clear water.
On De Gennes narrowing of fluids confined at the molecular scale in nanoporous materials
Authors: Kellouai Wanda , Barrat Jean-Louis , Judeinstein Patrick , Plazanet Marie , Coasne Benoit
Published: January 2024

Beyond well-documented confinement and surface effects arising from the large internal surface and severely confining porosity of nanoporous hosts, the transport of nanoconfined fluids remains puzzling in many aspects. With striking examples such as memory, i.e., non-viscous effects, intermittent dynamics, and surface barriers, the dynamics of fluids in nanoconfinement challenge classical formalisms (e.g., random walk, viscous/advective transport)—especially for molecular pore sizes. In this context, while molecular frameworks such as intermittent Brownian motion, free volume theory, and surface diffusion are available to describe the self-diffusion of a molecularly confined fluid, a microscopic theory for collective diffusion (i.e., permeability), which characterizes the flow induced by a thermodynamic gradient, is lacking. Here, to fill this knowledge gap, we invoke the concept of “De Gennes narrowing,” which relates the wavevector-dependent collective diffusivity D0(q) to the fluid structure factor S(q). First, using molecular simulation for a simple yet representative fluid confined in a prototypical solid (zeolite), we unravel an essential coupling between the wavevector-dependent collective diffusivity and the structural ordering imposed on the fluid by the crystalline nanoporous host. Second, despite this complex interplay with marked Bragg peaks in the fluid structure, the fluid collective dynamics is shown to be accurately described through De Gennes narrowing. Moreover, in contrast to the bulk fluid, the departure from De Gennes narrowing for the confined fluid in the macroscopic limit remains small as the fluid/solid interactions in severe confinement screen collective effects and, hence, weaken the wavevector dependence of collective transport.
Coarse-graining collective skyrmion dynamics in confined geometries
Authors: Winkler Thomas Brian , Rothörl Jan , Brems Maarten A. , Beneke Grischa , Fangohr Hans , Kläui Mathias
Published: January 2024

Magnetic skyrmions are magnetic quasi-particles with enhanced stability and different manipulation mechanisms using external fields and currents, making them promising candidates for future applications such as neuromorphic computing. Recently, several measurements and simulations have shown that thermally activated skyrmions in confined geometries, as they are necessary for device applications, arrange themselves predominantly based on commensurability effects. In this simulational study, based on the Thiele model, we investigate the enhanced dynamics and degenerate non-equilibrium steady state of a system in which the intrinsic skyrmion–skyrmion and skyrmion–boundary interaction compete with thermal fluctuations as well as current-induced spin–orbit torques. The investigated system is a triangular-shaped confinement geometry hosting four skyrmions, where we inject spin-polarized currents between two corners of the structure. We coarse grain the skyrmion states in the system to analyze the intricacies of arrangements of the skyrmion ensemble. In the context of neuromorphic computing, such methods address the key challenge of optimizing readout positions in confined geometries and form the basis for understanding collective skyrmion dynamics in systems with competing interactions on different scales. The findings are corroborated by experimental measurements.
Diagrammatic theory of magnetic and quadrupolar contributions to sum-frequency generation in composite systems
Authors: Noblet Thomas , Busson Bertrand
Published: January 2024

Second-order nonlinear processes like Sum-Frequency Generation (SFG) are essentially defined in the electric dipolar approximation. However, when dealing with the SFG responses of bulk, big nanoparticles, highly symmetric objects, or chiral species, magnetic and quadrupolar contributions play a significant role in the process too. We extend the diagrammatic theory for linear and nonlinear optics to include these terms for single objects as well as for multipartite systems in interaction. Magnetic and quadrupolar quantities are introduced in the formalism as incoming fields, interaction intermediates, and sources of optical nonlinearity. New response functions and complex nonlinear processes are defined, and their symmetry properties are analyzed. This leads to a focus on several kinds of applications involving nanoscale coupled objects, symmetric molecular systems, and chiral materials, both in line with the existing literature and opening new possibilities for original complex systems.
Evolution of Dasyurid Marsupials
Authors: Krajewski Carey , Westerman Michael , Woolley Patricia
Published: January 2024

The marsupial family Dasyuridae has a history of study extending from 18th century naturalists to the modern genomics era. The Evolution of Dasyurid Marsupials: Systematics and Family History tells the story of dasyurid evolution as it unfolded in the context of changing world views on biodiversity, biotic history and scientific methodology, from its roots in Enlightenment taxonomy to its transformation by the Darwinian and Hennigian revolutions, and then its maturation as statistical phylogenetics and phylogenomics.

Research on dasyurids includes every major approach in animal systematics, including some for which few comparable examples exist. It extends beyond the recent consensus on species relationships to include the timing of diversification, historical biogeography and the evolution of key phenotypic traits. This book introduces readers to living and fossil dasyurids, the questions evolutionary biologists have asked about them, the inferential methods used to answer those questions and the implications of those answers for understanding the history of this fascinating marsupial family. It offers a comprehensive synthesis of dasyurid evolutionary biology for students, teachers and researchers in mammalian evolution and marsupial biology.
Pathway-selective optogenetics reveals the functional anatomy of top–down attentional modulation in the macaque visual cortex
Authors: Hüer Janina , Saxena Pankhuri , Treue Stefan
Published: January 2024

Spatial attention represents a powerful top–down influence on sensory responses in primate visual cortical areas. The frontal eye field (FEF) has emerged as a key candidate area for the source of this modulation. However, it is unclear whether the FEF exerts its effects via its direct axonal projections to visual areas or indirectly through other brain areas and whether the FEF affects both the enhancement of attended and the suppression of unattended sensory responses. We used pathway-selective optogenetics in rhesus macaques performing a spatial attention task to inhibit the direct input from the FEF to area MT, an area along the dorsal visual pathway specialized for the processing of visual motion information. Our results show that the optogenetic inhibition of the FEF input specifically reduces attentional modulation in MT by about a third without affecting the neurons’ sensory response component. We find that the direct FEF-to-MT pathway contributes to both the enhanced processing of target stimuli and the suppression of distractors. The FEF, thus, selectively modulates firing rates in visual area MT, and it does so via its direct axonal projections.
Control of cardiac contractions using Cre-lox and degron strategies in zebrafish
Authors: Juan Thomas , Bellec Maëlle , Cardoso Bárbara , Athéa Héloïse , Fukuda Nana , Albu Marga , Günther Stefan , Looso Mario , Stainier Didier Y. R.
Published: January 2024

Cardiac contractions and hemodynamic forces are essential for organ development and homeostasis. Control over cardiac contractions can be achieved pharmacologically or optogenetically. However, these approaches lack specificity or require direct access to the heart. Here, we compare two genetic approaches to control cardiac contractions by modulating the levels of the essential sarcomeric protein Tnnt2a in zebrafish. We first recombine a newly generated
tnnt2a
floxed allele using multiple lines expressing Cre under the control of cardiomyocyte-specific promoters, and show that it does not recapitulate the
tnnt2a/silent heart
mutant phenotype in embryos. We show that this lack of early cardiac contraction defects is due, at least in part, to the long half-life of
tnnt2a
mRNA, which masks the gene deletion effects until the early larval stages. We then generate an endogenous Tnnt2a-eGFP fusion line that we use together with the zGRAD system to efficiently degrade Tnnt2a in all cardiomyocytes. Using single-cell transcriptomics, we find that Tnnt2a depletion leads to cardiac phenotypes similar to those observed in
tnnt2a
mutants, with a loss of blood and pericardial flow-dependent cell types. Furthermore, we achieve conditional degradation of Tnnt2a-eGFP by splitting the zGRAD protein into two fragments that, when combined with the cpFRB2-FKBP system, can be reassembled upon rapamycin treatment. Thus, this Tnnt2a degradation line enables non-invasive control of cardiac contractions with high spatial and temporal specificity and will help further understand how they shape organ development and homeostasis.
Phylogenomics of the psychoactive mushroom genus
Psilocybe
and evolution of the psilocybin biosynthetic gene cluster
Authors: Bradshaw Alexander J. , Ramírez-Cruz Virginia , Awan Ali R. , Furci Giuliana , Guzmán-Dávalos Laura , Dentinger Bryn T. M.
Published: January 2024

Psychoactive mushrooms in the genus
Psilocybe
have immense cultural value and have been used for centuries in Mesoamerica. Despite the recent surge of interest in these mushrooms due to the psychotherapeutic potential of their natural alkaloid psilocybin, their phylogeny and taxonomy remain substantially incomplete. Moreover, the recent elucidation of the psilocybin biosynthetic gene cluster is known for only five of ~165 species of
Psilocybe
, four of which belong to only one of two major clades. We set out to improve the phylogeny of
Psilocybe
using shotgun sequencing of fungarium specimens, from which we obtained 71 metagenomes including from 23 types, and conducting phylogenomic analysis of 2,983 single-copy gene families to generate a fully supported phylogeny. Molecular clock analysis suggests the stem lineage of
Psilocybe
arose ~67 mya and diversified ~56 mya. We also show that psilocybin biosynthesis first arose in
Psilocybe
, with 4 to 5 possible horizontal transfers to other mushrooms between 40 and 9 mya. Moreover, predicted orthologs of the psilocybin biosynthetic genes revealed two distinct gene orders within the biosynthetic gene cluster that corresponds to a deep split within the genus, possibly a signature of two independent acquisitions of the cluster within
Psilocybe
.
Toward the quantification of α-synuclein aggregates with digital seed amplification assays
Authors: Gilboa Tal , Swank Zoe , Thakur Rohan , Gould Russell A. , Ooi Kean Hean , Norman Maia , Flynn Elizabeth A. , Deveney Brendan T. , Chen Anqi , Borberg Ella , Kuzkina Anastasia , Ndayisaba Alain , Khurana Vikram , Weitz David A. , Walt David R.
Published: January 2024

The quantification and characterization of aggregated α-synuclein in clinical samples offer immense potential toward diagnosing, treating, and better understanding neurodegenerative synucleinopathies. Here, we developed digital seed amplification assays to detect single α-synuclein aggregates by partitioning the reaction into microcompartments. Using pre-formed α-synuclein fibrils as reaction seeds, we measured aggregate concentrations as low as 4 pg/mL. To improve our sensitivity, we captured aggregates on antibody-coated magnetic beads before running the amplification reaction. By first characterizing the pre-formed fibrils with transmission electron microscopy and size exclusion chromatography, we determined the specific aggregates targeted by each assay platform. Using brain tissue and cerebrospinal fluid samples collected from patients with Parkinson’s Disease and multiple system atrophy, we demonstrated that the assay can detect endogenous pathological α-synuclein aggregates. Furthermore, as another application for these assays, we studied the inhibition of α-synuclein aggregation in the presence of small-molecule inhibitors and used a custom image analysis pipeline to quantify changes in aggregate growth and filament morphology.
LHFPL5 is a key element in force transmission from the tip link to the hair cell mechanotransducer channel
Authors: Beurg Maryline , Schwalbach Evan Travis , Fettiplace Robert
Published: January 2024

During auditory transduction, sound-evoked vibrations of the hair cell stereociliary bundles open mechanotransducer (MET) ion channels via tip links extending from one stereocilium to its neighbor. How tension in the tip link is delivered to the channel is not fully understood. The MET channel comprises a pore-forming subunit, transmembrane channel-like protein (TMC1 or TMC2), aided by several accessory proteins, including LHFPL5 (lipoma HMGIC fusion partner-like 5). We investigated the role of LHFPL5 in transduction by comparing MET channel activation in outer hair cells of
Lhfpl5−/−
knockout mice with those in
Lhfpl5+/−
heterozygotes. The 10 to 90 percent working range of transduction in
Tmc1+/+; Lhfpl5+/−
was 52 nm, from which the single-channel gating force, Z, was evaluated as 0.34 pN. However, in
Tmc1+/+; Lhfpl5−/−
mice, the working range increased to 123 nm and Z more than halved to 0.13 pN, indicating reduced sensitivity. Tip link tension is thought to activate the channel via a gating spring, whose stiffness is inferred from the stiffness change on tip link destruction. The gating stiffness was ~40 percent of the total bundle stiffness in wild type but was virtually abolished in
Lhfpl5−/−,
implicating LHFPL5 as a principal component of the gating spring. The mutation
Tmc1
p.D569N reduced the LHFPL5 immunolabeling in the stereocilia and like
Lhfpl5−/−
doubled the MET working range, but other deafness mutations had no effect on the dynamic range. We conclude that tip-link tension is transmitted to the channel primarily via LHFPL5; residual activation without LHFPL5 may occur by direct interaction between PCDH15 and TMC1.
Translating what the image conveys or what it arouses?
Authors: Lautenbacher Olli Philippe
Published: January 2024

An ideal strongly anchored in the realm of translation is that of “translating without additions or
modifications.” However, with multimodal texts, one is confronted with the problem posed by the image, its reading, and its
interpretation. This article aims to better delineate the interpretative threshold between the global meaning that a still image
might convey in and of itself, on the one hand, and the more personal interpretations that this image can arouse in its receiver
(including the translator) on the other. In passing, the article also aims to suggest new ways of sensitizing translation students
to the existence of such a threshold. The principle, based on Sperber and Wilson’s relevance theory and its strong vs. weak
implicature continuum, is that the visual and compositional cues of the image, their relative salience, and their eventual
semantic convergence, combined with contextual factors in the initial production of the visual document, would constitute the
fundamental semiotic data to be considered in the translation process. Conversely, any projection of meaning external to the
image, and emanating from the translator-interpreter himself, would have to be treated with more circumspection within that
process, since it would amount to recontextualizing the original visual message by coloring it with a particular meaning, in other
words modifying it through added meanings. The corpus used for the observations consists of analyses of a photographic image made
by MA-level students in Translation Studies.
Lost in translation
Authors: Fehn Anne-Maria , Rocha Jorge
Published: January 2024

Here, we provide new perspectives on the relationship between the extinct Angolan language Kwadi and the Khoe
languages of southern Africa. Using an innovative approach which combines newly collected data from two Kwadi rememberers with a
reanalysis of historical recordings and fieldnotes, we were able to reconstitute the Kwadi phoneme inventory and relate Kwadi to
Proto-Khoe and its daughter branches Khoekhoe and Kalahari Khoe through regular sound correspondences. Our reconstruction of 127
lexical roots in form and meaning provides further evidence for a Khoe-Kwadi language family and shows that the lexical and
phonological proximity between Proto-Khoe-Kwadi and Proto-Khoe is closer than would be expected from the significant differences
that Khoe and Kwadi display in the domains of morphology and syntax. Taken together, our study contributes to a better
understanding of diachronic sound change in languages with phonemic click sounds and introduces novel ways to incorporate
different historical data sources.
Missionary linguistics in the East Indies in the seventeenth century
Authors: Joby Christopher
Published: January 2024

In recent years, there has been increased academic interest in missionary linguistics. However, whereas much has been written on Spanish missionary linguistics, above all in the Americas, relatively little has been published on Dutch missionary linguistics. This article aims to address this situation by analyzing the texts written in Malay by Dutch missionary linguists in the seventeenth century in the East Indies, now Indonesia. It begins by providing an account of the history of the Malay language, focusing above all on the influence of other languages including Sanskrit, Arabic, and Portuguese on the Malay lexicon. It then describes the activities of the Dutch East India Company in the Indonesian archipelago. After providing a comprehensive account of the texts that the Dutch missionary linguists wrote in Malay, the article analyzes the linguistic strategies that they employed as they attempted to overcome the gap between their language and culture and the Malay language and the culture in which it was embedded. It does so using a fourfold typology: loanwords, loan translations or calques; periphrasis and conceptual transfer. The picture that emerges is that authors made extensive use of all four strategies to communicate the Christian Gospel in Malay. One interesting result is that Dutch missionary linguistics used very few Dutch loanwords in their Malay texts. The article analyzes possible reasons for this.
The construction of Hong Kong’s “one country, two systems” in China Daily
Authors: Deng Jiange , Lin Zhongxuan
Published: January 2024

“One country, two systems” (OCTS) is the constitutional principle that established Hong Kong’s high degree of
autonomy after the city’s handover from Britain to China in 1997. This study conducts the first systemic, diachronic analysis of
the discursive construction of OCTS in Chinese news media, focusing on Beijing’s mouthpiece and public diplomacy newspaper,
China Daily. After reviewing the tripartite representation of the principle in the literature, we identify a
refocus from the economic to the legal-political aspect of OCTS and an increasing emphasis on the socio-cultural dimension of OCTS
in China Daily’s news discourses from 1997 to 2020. These patterns indicated OCTS’s changing status from a ‘legitimating ideology’
to a political principle struggling to be ‘legitimate’ in Beijing’s political discourses. Despite disputes about OCTS, we
anticipate that Beijing and Hong Kong’s opposition will continue to abide by this principle in their future interactions.
Political homophobia
Authors: Schäfer Saskia
Published: January 2024

This article comparatively analyses the rise of anti-LGBT rhetoric in Indonesia and Turkey in the 2010s and early
2020s. In both countries, periods of greater public visibility of LGBTQ+ people in the early 2000s were followed by waves of
severe anti-LGBT rhetoric, violence, and legal measures. This analysis focusses on the rhetoric that conservative state and
non-state actors use to other non-heteronormative people and to exclude them from the nation or “the people”. My main argument is
that state and non-state actors conduct othering of LGBTQ+ people and construct them as dangerous threats to the nation and to the
structure of the family. The anti-LGBT narratives are integrated into larger conspiracy narratives of foreign powers undermining
the nation.
Are religion metaphors anti‑revolutionary?
Authors: Augé Anaïs
Published: January 2024

This paper investigates the socio-political implications of sceptical metaphors in French discourse about the
climate crisis. Existing literature has demonstrated the prevalence of religion metaphors in English sceptical discourse.
Yet, in France, religious references in language use are limited as such references have been considered “anti-revolutionary”
since the storming of the Bastille, in 1789. I thus ask to what extent sceptical metaphors in French climate crisis discourse
differ from English sceptical metaphors. To this aim, I conduct a corpus-based study relying on texts published in the
extreme-right wing French newspaper “Valeurs Actuelles”. The metaphors identified in this corpus are analysed so as to uncover the
mini-narratives related to sceptical metaphor scenarios. Consistent with existing literature, the analysis establishes the
prevalence of the religion scenario. However, the research highlights significant argumentative exploitations: metaphor
users define the source concept according to cultural viewpoints on religion and ideological understanding of the
religious lexicon. I demonstrate that religion metaphors prevail because associated source concepts (environmentalism
as islam) are not conceived as being part of the domain of religion, according to these (extreme-right-wing)
discourse producers.