bluuebunny/crossref_metadata_2025 huggingface dataset:
Near-field spectroscopy of Dirac plasmons in Bi2Se3 ribbon arrays
Authors: Hale Lucy L. , Wang Zhengtianye , Harris C. Thomas , Brener Igal , Law Stephanie , Mitrofanov Oleg
Published: May 2023

Plasmons supported in the massless electron surface states of topological insulators (TIs), known as Dirac plasmons, have great potential in next generation optoelectronics. However, their inherent confinement to the surface makes the investigation of Dirac plasmons challenging. Near-field techniques provide the ideal platform to directly probe Dirac plasmons due to the sensitivity to evanescent fields at the surface. Here, we demonstrate the use of aperture near-field spectroscopy for the investigation of localized terahertz (THz) Dirac plasmon resonances in Bi2Se3 ribbon arrays with widths ranging from 10 to 40 µm. Unlike scattering THz near-field techniques, the aperture method is most sensitive to plasmons with the relevant lower-momenta corresponding to plasmon wavelengths on the scale of ∼20 µm. The combination of THz time-domain spectroscopy and aperture near-field microscopy enables sampling of localized Dirac plasmons in the near-field zone in the 0.5–2.5 THz range. We map the plasmon dispersion, which reveals a coupled plasmon–phonon polariton interaction. The near-field spectra show a higher contrast of the upper polariton branch in comparison with far-field observations. The information revealed by aperture near-field spectroscopy could deepen our understanding of the behavior of Dirac plasmons, leading to the potential development of real-world TI devices.
Universality in conformations and transverse fluctuations of a semi-flexible polymer in a crowded environment
Authors: Bair Jacob , Seth Swarnadeep , Bhattacharya Aniket
Published: May 2023

We study the universal aspects of polymer conformations and transverse fluctuations for a single swollen chain characterized by a contour length L and a persistence length ℓp in two dimensions (2D) and three dimensions (3D) in the bulk, as well as in the presence of excluded volume (EV) particles of different sizes occupying different area/volume fractions. In the absence of the EV particles, we extend the previously established universal scaling relations in 2D [Huang et al., J. Chem. 140, 214902 (2014)] to include 3D and demonstrate that the scaled end-to-end distance ⟨RN2⟩/(2Lℓp) and the scaled transverse fluctuation ⟨l⊥2⟩/L as a function of L/ℓp collapse onto the same master curve, where ⟨RN2⟩ and ⟨l⊥2⟩ are the mean-square end-to-end distance and transverse fluctuations. However, unlike in 2D, where the Gaussian regime is absent due to the extreme dominance of the EV interaction, we find that the Gaussian regime is present, albeit very narrow in 3D. The scaled transverse fluctuation in the limit L/ℓp ≪ 1 is independent of the physical dimension and scales as ⟨l⊥2⟩/L∼(L/ℓp)ζ−1, where ζ = 1.5 is the roughening exponent. For L/ℓp ≫ 1, the scaled fluctuation scales as ⟨l⊥2⟩/L∼(L/ℓp)ν−1, where ν is the Flory exponent for the corresponding spatial dimension (ν2D = 0.75 and ν3D = 0.58). When EV particles of different sizes for different area or volume fractions are added into 2D and 3D systems, our results indicate that the crowding density either does not or does only weakly affect the universal scaling relations. We discuss the implications of these results in living matter by showing the experimental result for a dsDNA on the master plot.
Flash x-ray radiography analysis of detonation wave propagation in additive-manufactured high explosives
Authors: Brown Cameron B. , Smilowitz Laura B. , Remelius Dennis K. , Schmalzer Andrew M. , Tappan Bryce C. , Aslam Tariq D. , Sridhar Seetharaman , Mueller Alexander H.
Published: May 2023

Recent research has demonstrated that additive manufacturing (AM) can be used to produce directionally sensitive high explosives (HEs), but detonation wave propagation in AM HEs with variable internal structure has not been studied. In this work, samples were printed using a 73 wt. % octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine-based HE ink. Flash x-ray radiography imaging was used to observe density changes in two imaging planes of each sample during detonation, and high-speed imaging was used to calculate the detonation velocity at the HE surface. The detonation front initially appears to fail in internal channel regions of the HE, but late reactions occurred in two samples, which increased the material bulk density by 2.8%, possibly due to shock convergence phenomena. The calculated detonation wave pressure similarly increased, but the accuracy of the results is uncertain because of the deviation of the low bulk density printed samples from the cast charge principal isentrope. This work demonstrates that structure can be effectively utilized to guide detonation wave propagation through HE charges.
Research on the natural frequencies of an integrated offshore wind turbine model considering blades
Authors: Meng Xiaowei , Zhai Endi , Xu Chengshun , Sun Yilong , Shi Shigang
Published: May 2023

The offshore wind turbine (OWT) is a high-rise structure that is extremely sensitive to dynamic loads such as wind, waves, and earthquakes. Therefore, in order to avoid resonance, it is extremely important to accurately calculate the natural frequencies of the OWT at the design stage. The integrated finite element model of DTU (Technical University of Denmark) 10 MW OWT is established based on OpenSees finite element software. The correctness of the superstructure simplification method is confirmed by comparing it to the frequencies calculated by the wind turbine dynamic analysis software HAWC2 for the single-blade model and the fixed constraint model at the bottom of the tower. The frequencies and mode shapes calculated by the overall model are compared with those calculated by the fixed model at the mudline and the concentrated mass model at the top of the tower. Then, the parameters of the soil shear modulus G0, void ratio e, pile embedded length L, pile diameter D, water depth, and blade stiffness are analyzed using the lumped mass model and the blade model at the top of the tower, and some regular conclusions about the variation of natural frequency with the parameters are obtained. Finally, based on the blade model, the influence of short-term cyclic loading on the natural frequency for OWT monopiles in dense sand is studied. The results indicate that the pile-soil interaction has a significant impact on the natural frequencies, the blade has a higher influence on the second bending frequency of the OWT, and the front-after direction is more significantly impacted than the side-side direction. The short-term cyclic loading are unlikely to significantly affect natural frequency for OWT monopiles in dense sand.
Crumpling electret films for a stronger macroscopic flexoelectric response
Authors: Ma Jianhua , Chen Lingling , Xu Jinrui , Yang Shengyou , Wang Binglei
Published: May 2023

Flexoelectricity is a universal phenomenon in all dielectrics, which couples electrical polarizations with strain gradients. However, limited by the size effects, the intensity of the flexoelectric effect becomes appreciable at the micro- and nano-scale, which suppresses its applications at the macroscale. To amend this inconvenience in applications, we innovatively propose replacing the traditional pure dielectric film with flexoelectret film containing quasi-permanent electrical charges in crumpling deformation. The crumpled flexoelectret film can give a considerable flexoelectric-like response at the macroscale. Specifically, we establish a theoretical model for the crumpled flexoelectret film, derive the analytical solution of the electromechanical coupling under the bi-directional bending conditions, and analyze the flexoelectric-like response under different thicknesses, charge densities, and scales. The results show that when the flexoelectret film’s thickness H=1mm and the charge density q=−0.2mC ⋅m−2, the intensity of its flexoelectric-like response is nearly 100 times of that of pure dielectric film’s intrinsic flexoelectricity.
Stokes–Einstein relation without hydrodynamic diameter in the TIP4P/Ice water model
Authors: Khrapak S. A. , Khrapak A. G.
Published: May 2023

It is demonstrated that self-diffusion and shear viscosity data for the TIP4P/Ice water model reported recently [Baran et al., J. Chem. Phys. 158, 064503 (2023)] obey the microscopic version of the Stokes–Einstein relation without the hydrodynamic diameter.
The kinetics of the ice–water interface from ab initio machine learning simulations
Authors: Montero de Hijes P. , Romano S. , Gorfer A. , Dellago C.
Published: May 2023

Molecular simulations employing empirical force fields have provided valuable knowledge about the ice growth process in the past decade. The development of novel computational techniques allows us to study this process, which requires long simulations of relatively large systems, with ab initio accuracy. In this work, we use a neural-network potential for water trained on the revised Perdew–Burke–Ernzerhof functional to describe the kinetics of the ice–water interface. We study both ice melting and growth processes. Our results for the ice growth rate are in reasonable agreement with previous experiments and simulations. We find that the kinetics of ice melting presents a different behavior (monotonic) than that of ice growth (non-monotonic). In particular, a maximum ice growth rate of 6.5 Å/ns is found at 14 K of supercooling. The effect of the surface structure is explored by investigating the basal and primary and secondary prismatic facets. We use the Wilson–Frenkel relation to explain these results in terms of the mobility of molecules and the thermodynamic driving force. Moreover, we study the effect of pressure by complementing the standard isobar with simulations at a negative pressure (−1000 bar) and at a high pressure (2000 bar). We find that prismatic facets grow faster than the basal one and that pressure does not play an important role when the speed of the interface is considered as a function of the difference between the melting temperature and the actual one, i.e., to the degree of either supercooling or overheating.
The penta-hexa silicene: A promising candidate for intrinsic room temperature magnetic semiconductor
Authors: Tao Kun , Chen Rongrong , Kang Jiyong , Xue Desheng , Stepanyuk V. S. , Jia Chenglong
Published: May 2023

Performing ab initio calculations, we investigate electronic and magnetic properties of a silicon allotrope (PH-silicene) composed entirely by six silicon pentagons and two silicon hexagons. The dynamically and mechanically stable PH-silicene hosts two-dimensional honeycomb spin structures, which can be antiferromagnetic, ferromagnetic, or ferrimagnetic depending on the applied tensile strain and/or number of stacked layers. In particular, the transition temperature of an in-plane antiferromagnetic ground state and a strain-induced ferromagnetic state of monolayer PH-silicene is found to be around 533 and 80 K, respectively. This unusual metal-free magnetism can be explained by the d0 charge transfer mechanism. On the other hand, we show that the PH-silicene is an indirect semiconductor with the bandgap of 0.585 eV. When stacking up to 4-layers, they vary from the semiconductor, the semimetal to the normal metal. Our findings suggest PH-silicene as a promising candidate for the room temperature magnetic semiconductor and will pave a way for silicon based spintronic devices.
Carrier dynamics in blue, cyan, and green InGaN/GaN LEDs measured by small-signal electroluminescence
Authors: Li Xuefeng , Pant Nick , DeJong Elizabeth , Elshafiey Abdelrahman Tarief , Armitage Rob , Kioupakis Emmanouil , Feezell Daniel
Published: May 2023

We study the carrier dynamics for c-plane InGaN/GaN light-emitting diodes (LEDs) with various emission wavelengths near the green gap using a small-signal electroluminescence method. The LEDs were grown by Lumileds using state-of-the-art growth conditions. Radiative and non-radiative recombination rates are numerically separated, and the carrier recombination lifetime and carrier density are obtained. Experiment shows that the causes of efficiency reduction at longer wavelength in the present structures are injection efficiency decrease, radiative recombination rate decrease, and imbalance of the increase in Auger–Meitner and radiative terms due to the interplay between the carrier–current density relationship and the quantum-confined Stark effect (QCSE). The effects of QCSE, phase-space filling, and the carrier–current density relationship on efficiency reduction at longer wavelengths are examined separately with experimental data and Schrödinger–Poisson calculations. In addition, we confirm the scaling law between Cn and Bn under electrical injection and find that the increase in carrier density at a given current density is the primary cause for lower radiative efficiency at high current density in longer wavelength LEDs. Conversely, we do not observe a significant efficiency reduction at longer wavelengths from extrinsic material degradation.
Dielectric spectrum of a ferrofluid layer exposed to a gradient magnetic field
Authors: Rajňák Michal , Dolník Bystrík , Paulovičová Katarína , Cimbala Roman , Kopčanský Peter , Timko Milan , Parekh Kinnari , Upadhyay R. V.
Published: May 2023

A low-frequency dielectric response of a ferrofluid based on transformer oil and MnZn ferrite nanoparticles is investigated in a gradient magnetic field. Four ferrofluid samples of various nanoparticle concentrations were introduced into planar micro-capacitors located over a magnetized tip. The dielectric spectra were measured in the frequency range from 0.1 Hz to 200 kHz and in the local magnetic field up to 100 mT. The spectra exhibit a dielectric relaxation ascribed to nanoparticle interfacial polarization. The low-frequency spectrum of each ferrofluid decreases upon application of the magnetic field up to 20 mT. The decrease in dielectric permittivity is caused by a magnetic force acting on larger nanoparticles in the gradient magnetic field. It is assumed that the interfaces of the concentrated nanoparticles in the gradient field do not contribute to the effective dielectric response. This reduces the effective relaxation time and shifts the relaxation toward higher frequencies. The dielectric spectra are well described by a relaxation fit function consisting of one Havriliak–Negami and a conductivity term. The fitting confirms that the only effect of the gradient magnetic field on the dielectric spectra is the shift of the dielectric relaxation and the decrease of the amplitude in the imaginary permittivity. This behavior is evident from a master plot, where all dielectric relaxations are superimposed on a single line. The knowledge of the presented behavior of the ferrofluid may be valuable when applying a ferrofluid to sharply magnetized parts of various electrical equipment (wires, tips, screws, nails, edges) as a liquid dielectric medium.
Existence of global symmetries of divergence-free fields with first integrals
Authors: Perrella David , Duignan Nathan , Pfefferlé David
Published: May 2023

The relationship between symmetry fields and first integrals of divergence-free vector fields is explored in three dimensions in light of its relevance to plasma physics and magnetic confinement fusion. A Noether-type theorem is known: for each such symmetry, there corresponds a first integral. The extent to which the converse is true is investigated. In doing so, a reformulation of this Noether-type theorem is found for which the converse holds on what is called the toroidal region. Some consequences of the methods presented are quick proofs of the existence of flux coordinates for magnetic fields in high generality, without needing to assume a symmetry such as in the cases of magneto-hydrostatics or quasi-symmetry.
Net protein contribution from an intensive Australian pork supply chain
Authors: van Barneveld R. J. , Hewitt R. J. E. , D’Souza D. N.
Published: May 2023

Debate surrounding the adverse consequences of feeding human-edible feedstuffs to livestock can be addressed through calculation of the net protein contribution (NPC) of the production system. If the NPC is greater than 1.0 for the production system, then there are net benefits from the system for human populations with an ever-increasing requirement for protein and amino acids. The aim of this paper was to calculate the NPC for an Australian pork supply chain on the basis of the unique characteristics of Australian ingredients. While calculation of NPC is not complex, intimate knowledge of the source of the nutrients and their quality, and interpretation of their human-edible protein fractions is essential if an accurate estimate is to be achieved. The NPC for an Australian pork supply chain was calculated using (a) actual, published or estimated values for human-edible fractions of feedstuffs, (b) the percentage of protein available within raw materials considered to be human edible, (c) recommended amino acid scoring patterns for infants, adolescents and adults, (d) published, and calculated from standard reference nutrient databases, digestible indispensable amino acid scores, (e) carcase yields and carcase composition from published studies, and (f) actual feed formulations, feed volumes and production data from a large Australian pork supply chain. The NPC for the assessed Australian pork supply chain was 3.26. This means the supply chain generates more than three times the human-edible protein it consumes in the process. This NPC is higher than previously published values, largely because of the composition of Australian pig diets, but demonstrates the positive value that livestock production systems make to human food supply. Livestock systems are often targeted as net consumers of vital nutrients such as protein and amino acids and the diversion of these nutrients from human diets. If production systems focus on the utilisation of waste streams, co-products and human-inedible feedstuffs, then they can make a net contribution to human-edible protein supply.
Managing a breeding population of endangered Carnaby’s Black–Cockatoo Calyptorhynchus latirostris on the edge of their range
Authors: Bourne Amanda R. , Garnaut Kahree , Dawson Rick , Beswick Heather , Blakeway Freda , Rycken Sam , Simkin Robin , Kendle Jarna
Published: May 2023

Context The Carnaby’s Black–Cockatoo Calyptorhynchus latirostris, an endangered species endemic to south-west Western Australia, has experienced a 30% contraction in range and 50% decline in population since the 1940s. A breeding population of Carnaby’s Black–Cockatoo was first described at Murchison House Station in the 1970s, but breeding had not been recorded there since the 1990s. Aims We sought to confirm whether Carnaby’s Black–Cockatoos were still breeding at this location at the far-northern edge of their range, hundreds of kilometres from the nearest known breeding site. Once confirmed, we compared population, hollow and nestling characteristics with those of other well-studied breeding populations of the same species and surveyed foraging and nesting habitat to evaluate population health and inform management. Methods We monitored 30 breeding attempts and characterised 21 confirmed hollows. We conducted comprehensive vegetation community surveys at nine sites. Key results We confirm that Carnaby’s Black–Cockatoos are still breeding at the far-northern edge of their range. Hollow and nestling characteristics are similar to breeding populations elsewhere. We found no evidence of plant recruitment for crucial foraging or nesting species. Conclusions The absence of plant recruitment in both foraging and nesting habitats suggests that active management will be required to support ongoing breeding. We recommend conserving and revegetating foraging and breeding habitat, maintaining hollows and/or providing artificial hollows while trees regenerate. Implications Foraging and breeding habitat will need long-term management to support ongoing breeding of this threatened species at the northern edge of its range.
Benefits of Using a Transdisciplinary Approach for the Design and Operationalization of a Surveillance System
Authors: Falzon Laura C. , Ogola Joseph , Fèvre Eric M. , Berezowski John
Published: May 2023

During the preparatory phase of a surveillance project in Western Kenya, it was noted that several animal health activities, including meat inspection, were recorded using paper-based forms. Through discussions with the meat inspectors and other slaughterhouse actors, an electronic meat inspection form was developed, tested, and used in two slaughterhouses in Bungoma County. The meat inspectors completed and submitted a form for every animal slaughtered at their facility over a 2.75-year period. In a feedback meeting with the meat inspectors and other stakeholders, areas for improvement were highlighted, such as the timely provision of feedback to the data providers, and the inclusion of data fields that allow for more detailed animal movement information. The meat inspectors remarked that the form made them feel appreciated and added value to their work as the data could be used to educate farmers on prevailing livestock conditions and provide economic incentives for disease control interventions. The data submitted via the electronic forms were of sufficient quality to be summarized and identify trends in the animal slaughterhouse throughput, as well as frequent reasons for meat condemnation and associated costs. These data could therefore set the foundation for a syndromic surveillance system based on slaughterhouse data. Other non-traditional data sources, such as livestock and meat transport certificates, could also be leveraged to create a post-farm animal health information system.

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© The Authors 2023
Factors affecting evolutions of contact area formation and bonding strength in pure Cu/Cu joints produced by ultrasonic spot welding
Authors: Hu Kuan-Chieh , Lin I.-Chen , Liu Zi-Yuan , Lin Jhe-Yu
Published: May 2023

In this study, the effect of bonding surface conditions on the strength evolution of Cu/Cu joints during ultrasonic welding was investigated. Lap shear tests and microstructure characterisation revealed that contact area formation could be affected by bonding surface conditions and clamping force. That is, the fraction of contact area quickly evolved with smoother bonding surfaces, leading to a rapid strength increase to base metal fracture (1100 N of lap shear load after 1.0 s of welding). Comparatively, rough surface combinations exhibited a slow strength evolution owing to a lower fraction of contact areas. To overcome this situation, a higher clamping force was employed to facilitate contact area formation (1100 N of lap shear load after 0.5 s of welding).
Flows for the masses: A multi-fluid non-linear perturbation theory for massive neutrinos
Authors: Chen Joe Zhiyu , Upadhye Amol , Wong Yvonne Y.Y.
Published: May 2023

Velocity dispersion of the massive neutrinos presents a daunting challenge for non-linear cosmological perturbation theory. We consider the neutrino population as a collection of non-linear fluids, each with uniform initial momentum, through an extension of the Time Renormalization Group perturbation theory. Employing recently-developed Fast Fourier Transform techniques, we accelerate our non-linear perturbation theory by more than two orders of magnitude, making it quick enough for practical use. After verifying that the neutrino mode-coupling integrals and power spectra converge, we show that our perturbation theory agrees with N-body neutrino simulations to within 10% for neutrino fractions Ω
ν,0
h
2 ≤ 0.005 up to wave numbers of k = 1 h/Mpc, an accuracy consistent with ≤ 2.5% errors in the neutrino mass determination. Non-linear growth represents a > 10% correction to the neutrino power spectrum even for density fractions as low as Ω
ν,0
h
2 = 0.001, demonstrating the limits of linear theory for accurate neutrino power spectrum predictions. Our code FlowsForTheMasses is avaliable online at github.com/upadhye/FlowsForTheMasses.
Genome entropy and network centrality contrast exploration and exploitation in evolution of foodborne pathogens
Authors: Chang Sheryl L , Suster Carl J E , Rockett Rebecca J , Svahn Adam J , Cliff Oliver M , Arnott Alicia , Wang Qinning , Kim Rady , Suliman Basel , Gall Mailie , Sorrell Tania C , Sintchenko Vitali , Prokopenko Mikhail
Published: May 2023

Modelling evolution of foodborne pathogens is crucial for mitigation and prevention of outbreaks. We apply network-theoretic and information-theoretic methods to trace evolutionary pathways of Salmonella Typhimurium in New South Wales, Australia, by studying whole genome sequencing surveillance data over a five-year period which included several outbreaks. The study derives both undirected and directed genotype networks based on genetic proximity, and relates the network’s structural property (centrality) to its functional property (prevalence). The centrality-prevalence space derived for the undirected network reveals a salient exploration-exploitation distinction across the pathogens, further quantified by the normalised Shannon entropy and the Fisher information of the corresponding shell genome. This distinction is also analysed by tracing the probability density along evolutionary paths in the centrality-prevalence space. We quantify the evolutionary pathways, and show that pathogens exploring the evolutionary search-space during the considered period begin to exploit their environment (their prevalence increases resulting in outbreaks), but eventually encounter a bottleneck formed by epidemic containment measures.
Design of embedded software architecture for spacecraft electric propulsion system
Authors: Zhao Xingsong , Gu Bin , Dong Xiaogang , Li Xiaofeng , Zhong Ruiming
Published: May 2023

With the rapid growth of the number of spacecraft tasks and the complexity of the system, spacecraft software development is faced with the challenges of high-quality and rapid delivery, increased complexity, and frequent changes in requirements. The reuse rate of software assets needs to be improved urgently. In order to realize cross-platform and cross-project reuse of software design, this paper studies the design of electric propulsion software architecture. Carry out requirements decomposition and subsystem division of electric propulsion systems for different platforms, extract common requirements and variability requirements at the system level and subsystem level based on the Feature-Oriented Domain Analysis method, and establish a requirements model. Based on the requirements model, an electric propulsion software architecture integrating “event-driven + components” is proposed, and the classic event-driven model of “publish-subscribe” is adaptively improved. The architecture has been instantiated and applied to 16 projects on 4 platforms, and the reuse rate of core assets has reached 70%. This paper has certain guidance and reference significance for spacecraft software asset reuse and platform construction.
High rate studies of the ATLAS sTGC detector and optimization of the filter circuit on the input of the front-end amplifier
Authors: Sun Siyuan , Moleri Luca , Vasquez Gerardo , Teterin Peter , Corsetti Sabrina , Guan Liang , Lefebvre Benoit , Kajomovitz Enrique , Levinson Lorne , Lupu Nachman , McPherson Rob , Vdovin Alexander , Wang Rongkun , Zhou Bing , Zhu Junjie
Published: May 2023

The Large Hadron Collider (LHC) at CERN is expected to be upgraded to the High-Luminosity LHC (HL-LHC) by 2029 and achieve instantaneous luminosity around 5–7.5 × 10^34 cm^-2 s^-1. This represents a more than 3–4 fold increase in the instantaneous luminosity compared to what has been achieved in Run 2. The New Small Wheel (NSW) upgrade is designed to be able to operate efficiently in this high background rate environment. In this article, we summarize multiple performance studies of the small-strip Thin Gap Chamber (sTGC) at high rate using nearly final front-end electronics. We demonstrate that the efficiency versus rate distribution can be well described by an exponential decay with electronics dead-time being the primary cause of loss of efficiency at high rate. We then demonstrate several methods that can decrease the electronics dead-time and therefore minimize efficiency loss. One such method is to install either a pi-network input filter or pull-up resistor to minimize the charge input into the amplifier. We optimized the pi-network capacitance and pull-up resistor resistance using the results from our measurements. The results shown here were not only critical to finalizing the components on the front-end board, but also are critical for setting the optimal operating parameters of the sTGC detector and electronics in the ATLAS cavern.
A measure of perceived quality to secure the polishability of new paint systems
Authors: Rebeggiani Sabina , Rosén B-G
Published: May 2023

The automotive industry continuously strives to reduce their environmental impact. For the paint shop it means to introduce more sustainable paint concepts, while maintaining the production rate and retain the right surface appearance that is crucial for the vehicle’s perceived quality. Today most painted parts are visually inspected and, if needed, manually repaired by abrasive polishing to eliminate spot defects. The repair process consists of one sanding step to remove the defect, and one or two rubbing/polishing steps to restore the surface, but still it tends to be a non-reliable process leaving patterns or clusters of shallow micro scratches seen as three-dimensional shapes moving over the surface when viewed from different angles like holograms. These so called ‘polishing roses’ are hard to detect in artificial light but clearly visible in Sunlight and therefore they constitute a constant quality issue. Accurate polishing procedures in combination with more objective inspection techniques would secure a high surface quality—but what is ‘accurate’? The overall scope of the study was to deepen the knowledge of paint systems to develop test routines for the polishability of coatings already during the development stage, and thereby ease the implementation of new coating systems in production. The study was based on collected process data from professional polishers to define a process window based on key parameters for successful end-of-line repairs of coated surfaces, i.e. strategies minimizing the occurrence of visible polishing traces. A CNC-machine was built up for the purpose to systematically test and evaluate new coating systems and repair procedures. The surface estimation was made by visual inspections as well as by a further developed photometric stereo system providing quantitative images of remaining repair traces.
Young’s double-slits goes temporal
Authors: Cartlidge Edwin
Published: May 2023

A “time” version of the famous experiment generates fringes in frequency rather than space, as Edwin Cartlidge explains.
Neutrinos probe the proton’s structure in surprising result
Authors: Jarman Sam
Published: May 2023

An international team has discovered a robust technique for probing the internal structure of the proton by using neutrino scattering.
Google reveals quantum error correction advance
Authors: Boerkamp Martijn
Published: May 2023

Martijn Boerkamp examines new work that could lead to fault-tolerant quantum computers.
UK unveils Horizon Europe ‘plan B’
Authors: Allen Michael
Published: May 2023

The UK government has published its long-awaited “plan B” for British science if negotiations to join the EU’s €95bn flagship Horizon Europe research programme fail.
UK announces 10-year £2.5bn quantum-research programme
Authors: Allen Michael
Published: May 2023

The UK government has launched a new National Quantum Strategy that will run from 2024 to 2034.
JUICE mission blasts off to study Jupiter’s icy moons
Authors: Banks Michael
Published: May 2023

The European Space Agency (ESA) has launched a mission to Jupiter that will test the conditions that may have led to the emergence of habitable environments.
Documenting a lasting legacy
Authors: Prescod-Weinstein Chanda
Published: May 2023

Chanda Prescod-Weinstein on efforts to create a bibliography of papers by Black women in physics.
UK spaceports: the good, the bad, the ugly
Authors: Skuse Benjamin
Published: May 2023

Are spaceports the missing link needed to catalyse the UK space industry, or are they a can of worms best left to established spacefaring nations? Benjamin Skuse investigates.
If the Milky Way could talk
Authors: Cullen Cait
Published: May 2023

Cait Cullen reviews The Milky Way: an Autobiography of our Galaxy by Moiya McTier.
A fast-paced adventure
Authors: Rao Achintya
Published: May 2023

Achintya Rao reviews the documentary film Rapid Motion Through Space: an Incomplete History of Speed written, directed and produced by Trent Burton.
Atomic layer deposition of thin films: from a chemistry perspective
Authors: Li Jinxiong , Chai Gaoda , Wang Xinwei
Published: May 2023

Atomic layer deposition (ALD) has become an indispensable thin-film technology in the contemporary microelectronics industry. The unique self-limited layer-by-layer growth feature of ALD has outstood this technology to deposit highly uniform conformal pinhole-free thin films with angstrom-level thickness control, particularly on 3D topologies. Over the years, the ALD technology has enabled not only the successful downscaling of the microelectronic devices but also numerous novel 3D device structures. As ALD is essentially a variant of chemical vapor deposition, a comprehensive understanding of the involved chemistry is of crucial importance to further develop and utilize this technology. To this end, we, in this review, focus on the surface chemistry and precursor chemistry aspects of ALD. We first review the surface chemistry of the gas–solid ALD reactions and elaborately discuss the associated mechanisms for the film growth; then, we review the ALD precursor chemistry by comparatively discussing the precursors that have been commonly used in the ALD processes; and finally, we selectively present a few newly-emerged applications of ALD in microelectronics, followed by our perspective on the future of the ALD technology.
Gonality of the modular curve 𝑋₀(𝑁)
Authors: Najman Filip , Orlić Petar
Published: May 2023

In this paper we determine the

Q

\mathbb {Q}

-gonalities of the modular curves

X
0

(
N
)

X_0(N)

for all

N
>
145

N>145

. We determine the

C

\mathbb {C}

-gonality of many of these curves and the

Q

\mathbb {Q}

-gonalities and

C

\mathbb {C}

-gonalities for many larger values of

N
N

.

Using these results and some further work, we determine all the modular curves

X
0

(
N
)

X_0(N)

of gonality

4
4

,

5
5

and

6
6

over

Q

\mathbb {Q}

. We also find the first known instances of pentagonal curves

X
0

(
N
)

X_0(N)

over

C

\mathbb {C}

.
An improvement of the Farrell-Jones conjecture for localising invariants
Authors: Reis José
Published: May 2023

The Farrell-Jones conjecture for lax monoidal finitary localising invariants was recently proved by Bunke-Kasprowski-Winges [On the Farrell-Jones conjecture for localising invariants, 2021, arXiv:2111.02490]. In this short note, making use of the theory of noncommutative motives, we prove that the lax monoidal assumption is not necessary.
Morita equivalences and the inductive blockwise Alperin weight condition for type 𝖠
Authors: Feng Zhicheng , Li Zhenye , Zhang Jiping
Published: May 2023

As a step to establish the blockwise Alperin weight conjecture for all finite groups, we verify the inductive blockwise Alperin weight condition introduced by Navarro–Tiep and Späth for simple groups of Lie typeA{\mathsf {A}}, split or twisted. Key to the proofs is to reduce the verification of the inductive condition to the isolated (that means unipotent) blocks, using the Jordan decomposition for blocks of finite reductive groups given by Bonnafé, Dat and Rouquier.
Integral representation of superoscillations via complex Borel measures and their convergence
Authors: Behrndt Jussi , Colombo Fabrizio , Schlosser Peter , Struppa Daniele
Published: May 2023

In the last decade there has been a growing interest in superoscillations in various fields of mathematics, physics and engineering. However, while in applications as optics the local oscillatory behaviour is the important property, some convergence to a plane wave is the standard characterizing feature of a superoscillating function in mathematics and quantum mechanics. Also there exists a certain discrepancy between the representation of superoscillations either as generalized Fourier series, as certain integrals or via special functions. The aim of this work is to close these gaps and give a general definition of superoscillations, covering the well-known examples in the existing literature. Superoscillations will be defined as sequences of holomorphic functions, which admit integral representations with respect to complex Borel measures and converge to a plane wave in the space

A

1

(

C

)

\mathcal {A}_1(\mathbb {C})

of entire functions of exponential type.
‘What is it?’ ‘It is a lewd goblin’: Taking Critical Cues from Illustrative Adaptations of Christina Rossetti’s Goblin Market
Authors: Figgins Kristen Layne
Published: May 2023

When adapters interpret a work over and over again, they focus on details that can shape the way we think about a text. Focusing on these adaptive details can often lead to seeing gaps in the criticism of a text. Such is the case with Goblin Market, a poem that critics have been noting is ‘ambiguous’ since its first publication in 1862. While most critics understand that this ambiguity centres on the sexual undertones of the poem, the key to understanding this allegory might be discovered by turning to illustrative adaptations. In all illustration, one detail is reproduced consistently: the goblins are visualised as animals. Yet animality is rarely discussed in criticism of the poem, and almost never with any depth. I argue that we can view adaptation as a type of meaning-making that literary and cultural critics might build upon when analysing familiar texts.
VII—Can Arguments Change Minds?
Authors: Dutilh Novaes Catarina
Published: May 2023

Can arguments change minds? Philosophers like to think that they can. However, a wealth of empirical evidence suggests that arguments are not very efficient tools to change minds. What to make of the different assessments of the mind-changing potential of arguments? To address this issue, we must take into account the broader contexts in which arguments occur, in particular the propagation of messages across networks of attention, and the choices that epistemic agents must make between alternative potential sources of content and information, which are very much influenced by perceptions of reliability and trustworthiness. Arguments can change minds, but only under conducive, favourable socio-epistemic conditions.
Locality-preserving minimal perfect hashing of k-mers
Authors: Pibiri Giulio Ermanno , Shibuya Yoshihiro , Limasset Antoine
Published: May 2023

Motivation

Minimal perfect hashing is the problem of mapping a static set of n distinct keys into the address space {1,…,n} bijectively. It is well-known that n log 2(e) bits are necessary to specify a minimal perfect hash function (MPHF) f, when no additional knowledge of the input keys is to be used. However, it is often the case in practice that the input keys have intrinsic relationships that we can exploit to lower the bit complexity of f. For example, consider a string and the set of all its distinct k-mers as input keys: since two consecutive k-mers share an overlap of k−1 symbols, it seems possible to beat the classic  log 2(e) bits/key barrier in this case. Moreover, we would like f to map consecutive k-mers to consecutive addresses, as to also preserve as much as possible their relationship in the codomain. This is a useful feature in practice as it guarantees a certain degree of locality of reference for f, resulting in a better evaluation time when querying consecutive k-mers.

Results

Motivated by these premises, we initiate the study of a new type of locality-preserving MPHF designed for k-mers extracted consecutively from a collection of strings. We design a construction whose space usage decreases for growing k and discuss experiments with a practical implementation of the method: in practice, the functions built with our method can be several times smaller and even faster to query than the most efficient MPHFs in the literature.
gExcite: a start-to-end framework for single-cell gene expression, hashing, and antibody analysis
Authors: Grob Linda , Bertolini Anne , Carrara Matteo , Lischetti Ulrike , Tastanova Aizhan , Beisel Christian , Levesque Mitchell P , Stekhoven Daniel J , Singer Franziska
Published: May 2023

Recently, CITE-seq emerged as a multimodal single-cell technology capturing gene expression and surface protein information from the same single cells, which allows unprecedented insights into disease mechanisms and heterogeneity, as well as immune cell profiling. Multiple single-cell profiling methods exist, but they are typically focused on either gene expression or antibody analysis, not their combination. Moreover, existing software suites are not easily scalable to a multitude of samples. To this end, we designed gExcite, a start-to-end workflow that provides both gene and antibody expression analysis, as well as hashing deconvolution. Embedded in the Snakemake workflow manager, gExcite facilitates reproducible and scalable analyses. We showcase the output of gExcite on a study of different dissociation protocols on PBMC samples.

Availability and implementation

gExcite is open source available on github at https://github.com/ETH-NEXUS/gExcite_pipeline. The software is distributed under the GNU General Public License 3 (GPL3).
Multi-modal deep learning improves grain yield prediction in wheat breeding by fusing genomics and phenomics
Authors: Togninalli Matteo , Wang Xu , Kucera Tim , Shrestha Sandesh , Juliana Philomin , Mondal Suchismita , Pinto Francisco , Govindan Velu , Crespo-Herrera Leonardo , Huerta-Espino Julio , Singh Ravi P , Borgwardt Karsten , Poland Jesse
Published: May 2023

Motivation

Developing new crop varieties with superior performance is highly important to ensure robust and sustainable global food security. The speed of variety development is limited by long field cycles and advanced generation selections in plant breeding programs. While methods to predict yield from genotype or phenotype data have been proposed, improved performance and integrated models are needed.

Results

We propose a machine learning model that leverages both genotype and phenotype measurements by fusing genetic variants with multiple data sources collected by unmanned aerial systems. We use a deep multiple instance learning framework with an attention mechanism that sheds light on the importance given to each input during prediction, enhancing interpretability. Our model reaches 0.754 ± 0.024 Pearson correlation coefficient when predicting yield in similar environmental conditions; a 34.8% improvement over the genotype-only linear baseline (0.559 ± 0.050). We further predict yield on new lines in an unseen environment using only genotypes, obtaining a prediction accuracy of 0.386 ± 0.010, a 13.5% improvement over the linear baseline. Our multi-modal deep learning architecture efficiently accounts for plant health and environment, distilling the genetic contribution and providing excellent predictions. Yield prediction algorithms leveraging phenotypic observations during training therefore promise to improve breeding programs, ultimately speeding up delivery of improved varieties.

Availability and implementation

Available at https://github.com/BorgwardtLab/PheGeMIL (code) and https://doi.org/doi:10.5061/dryad.kprr4xh5p (data).
Heart rate variability during slow wave sleep is linked to functional connectivity in the central autonomic network
Authors: Kong Shawn D X , Gordon Christopher J , Hoyos Camilla M , Wassing Rick , D’Rozario Angela , Mowszowski Loren , Ireland Catriona , Palmer Jake R , Grunstein Ronald R , Shine James M , McKinnon Andrew C , Naismith Sharon L
Published: May 2023

Reduced heart rate variability can be an early sign of autonomic dysfunction in neurodegenerative diseases and may be related to brain dysfunction in the central autonomic network. As yet, such autonomic dysfunction has not been examined during sleep—which is an ideal physiological state to study brain–heart interaction as both the central and peripheral nervous systems behave differently compared to during wakefulness. Therefore, the primary aim of the current study was to examine whether heart rate variability during nocturnal sleep, specifically slow wave (deep) sleep, is associated with central autonomic network functional connectivity in older adults ‘at-risk’ of dementia.

Older adults (n = 78; age range = 50–88 years; 64% female) attending a memory clinic for cognitive concerns underwent resting-state functional magnetic resonance imaging and an overnight polysomnography. From these, central autonomic network functional connectivity strength and heart rate variability data during sleep were derived, respectively. High-frequency heart rate variability was extracted to index parasympathetic activity during distinct periods of sleep, including slow wave sleep as well as secondary outcomes of non-rapid eye movement sleep, wake after sleep onset, and rapid eye movement sleep. General linear models were used to examine associations between central autonomic network functional connectivity and high-frequency heart rate variability.

Analyses revealed that increased high-frequency heart rate variability during slow wave sleep was associated with stronger functional connectivity (F = 3.98, P = 0.022) in two core brain regions within the central autonomic network, the right anterior insular and posterior midcingulate cortex, as well as stronger functional connectivity (F = 6.21, P = 0.005) between broader central autonomic network brain regions—the right amygdala with three sub-nuclei of the thalamus. There were no significant associations between high-frequency heart rate variability and central autonomic network connectivity during wake after sleep onset or rapid eye movement sleep.

These findings show that in older adults ‘at-risk’ of dementia, parasympathetic regulation during slow wave sleep is uniquely linked to differential functional connectivity within both core and broader central autonomic network brain regions. It is possible that dysfunctional brain–heart interactions manifest primarily during this specific period of sleep known for its role in memory and metabolic clearance. Further studies elucidating the pathophysiology and directionality of this relationship should be conducted to determine if heart rate variability drives neurodegeneration, or if brain degeneration within the central autonomic network promotes aberrant heart rate variability.
No Acceptable Losses: Risk, Prevention, and Justice
Authors: Scherz Paul
Published: May 2023

Beginning in the nineteenth century, social statistics inspired a vision of society as a population characterized by a certain distribution of risks. The introduction of the risk paradigm has deep implications for central concepts in Christian social ethics like distributive justice, with this vision leading to a new concept of distributive justice as the equal distribution of risk. This essay describes tensions that arise due to the risk paradigm in relation to distributive justice: risks can always be further reduced, risk mitigation creates other risks, and there is no inherent rule of justice for balancing risks. While recognition of shared risk can create social cohesion, it also leads to interest groups struggling over which risks to confront. The essay illustrates these problems with two examples from health care: preventive health programs that manage disease risk through medication, and debates over school closures in respond to the Covid pandemic. Christian bioethics, as it wrestles with issues of justice, must address the problems created by the risk paradigm.