bluuebunny/crossref_metadata_2025 huggingface dataset:
Micro-burrs in machining original molds of an optical functional film with a triangular pyramidal texture
Authors: Li Huang , Xu Zhilong
Published: April 2021

During the cutting process of the original molds, the micro-burrs produced by the machining process will affect the optical properties of the optical functional textured film. According to the forming planing method for the triangular pyramid texture, the formation characteristics of burrs are analyzed from the cut-in edge and the cut-out edge. And the influence of burrs on the triangular pyramid edge is analyzed in combination with the changes of cutting section, to obtain the prediction model of edge burr distribution. The cutting simulation of triangular pyramid texture shows that the main flow direction of the chips will be inclined along the side where the cutting edge is separated from the workpiece first, resulting in a larger exit burr size on this side. In the cut-out stage, as the contact length between the cutting edge of the tool and the workpiece decreases gradually, the maximum cutting stress gradually transfers to the tool tip so that the positive burrs form at the bottom of the cut-out edges of the triangular pyramid. The forming processing experiment for the triangular pyramid texture shows that there are both positive and negative exit burrs on the cut-out edges. Compared with the forming processing method, the V-shaped section of the cutting layer is changed to the trapezoidal section of the free chips when the original molds with triangular pyramid texture are cut by the single-edge cutting method. As the chips flow more smoothly, the size of burrs can be reduced. Besides, the ratio of the effective optical functional area K
s can increase 10.1%.
Pattern transferring of Prolift-100 polymer sacrificial layers with controlled sidewall profile
Authors: Silva Jorge R , Kala Hemendra , Tripathi Dhirendra K , Papanastasiou Kirsten , Silva K K M B Dilusha , Putrino Gino , Martyniuk Mariusz , Keating Adrian , Antoszewski Jarek , Faraone Lorenzo
Published: April 2021

While wet pattern transferring of polymers is faster than dry processing, it can lead to excessive undercut that will erode and distort features in patterned sacrificial regions during micro electro mechanical systems (MEMSs) fabrication. Dry etching processes based on O2, CF4 and N2 chemistry reduce undercutting of features to around 2 µm, but the resulting sidewall profiles of the patterned polymer islands are generally unsuitable for subsequent conformal deposition of thin films for surface micromachined MEMS fabrication. This paper presents a dry etching process for Prolift-100-16 polymer sacrificial layers, that employs a combination of a hard mask and a subsidiary sacrificial layer, that overcomes the limitations of undercut control and conformal deposition of physical vapour deposition techniques. The dry etching process is optimized to reduce the feature undercut to as low as 1 µm, while also producing sidewall profiles suitable for subsequent conformal deposition of thin films.
Conventional surface micromachining process for the fabrication of a linear optical phased array based on piston micromirrors
Authors: Mohammad Tarek , He Siyuan , Ben Mrad Ridha
Published: April 2021

Micro electromechanical system (MEMS) based optical phased array (OPA) technology generally demands narrow and tightly spaced suspended microstructures with high-aspect-ratio in the lateral dimensions. This paper presents an one dimensional OPA system which is fabricated using the standard PolyMUMPs process, leading to a low-cost, simplified and commercially accessible surface micromachining technique for the OPA technology. The proposed OPA device utilizes an array of metal-coated silicon micromirrors with high-aspect-ratio structures which act as optical phase shifters. Each micromirror along the array is individually actuated by an electrostatic parallel plate micro-actuator made of a micro-cantilever beam positioned above a fixed electrode. The field of view obtained by the device is measured as 4.76° which is comparable to those by the previous MEMS based OPA devices fabricated using custom-run and complex surface micromachining processes. The OPA device has a response time of 6.5 µs and an out of plane actuation stroke of 0.16 µm at a bias voltage of 55 V. The magnitude of the out of plane displacement by the phase shifters is equal to one-quarter of the laser wavelength (650 nm) used which leads to the desired optical phase shift of

π

radian.
Detection of electron spin resonance down to 10 K using localized spoof surface plasmon
Authors: Roy Subhadip , Nandi Anuvab , Das Pronoy , Mitra Chiranjib
Published: April 2021

In this study, novel use of the electromagnetic field profile of a localized spoof surface plasmonic mode to detect electron spin resonance (ESR) is being reported. The mode is supported on a resonator with a complementary metallic spiral structure, etched on the ground plane of a microstrip line having a characteristic impedance of 50 Ω. The change in characteristics of the mode of interest with lowering of temperature has been observed and analyzed. ESR spectra of three paramagnetic samples—2,2-diphenyl-1-picrylhydrazyl (DPPH), galvinoxyl, and 2,2,6,6-tetramethylpiperidine-1-oxyl are recorded using this resonator at room temperature. ESR spectra of DPPH are also captured down to 10 K. Potential application of the mode in the detection of microwave induced Rashba field-driven ESR has been discussed.
Shockwaves evolving on nanosecond timescales around individual micro-discharge filaments in deionised water
Authors: Hoffer Petr , Prukner Václav , Schmidt Jiří , Šimek Milan
Published: April 2021

In this study, we present an analysis of the pressure fields developing around nanosecond discharges produced in deionised water by positive high-voltage pulses (+130 and +170 kV) with a fast rise time on a tungsten anode pin. Shockwaves and their associated pressure characteristics were investigated by laser interferometry with a very high spatial resolution of 0.8 μm utilising the concept of a picosecond Mach–Zehnder interferometer based on a Nd:YAG laser (532 nm, 30 ps). Shifts of the fringes in interference patterns due to variations in the refractive index of liquid water produced in the vicinity of the tungsten anode were projected by the interferometer and analysed as a function of the pressure. High spatial resolution combined with the picosecond laser pulse allowed for the examination of frozen interferometric characteristics of cylindrical shockwaves. Consequently, unique results characterising the shockwaves developing around individual discharge filaments were obtained. For easier comparison, the shockwave pressures were normalised to a radius of 0.4 μm, which was found as the most probable maximum of initial radius of primary dark filament. At this radius, the most probable shock pressure was 1.5 GPa, whereas the highest obtained shock pressure reached 11 GPa. We showed that the modified Gaussian distribution fits the obtained results well. Finally, we observed that most of those extraordinary strong shock-fronts were associated with the dark filaments containing strong residual plasma-induced emission. This observation likely provides an indirect evidence of the electrostriction-assisted discharge onset mechanism.
Aluminum and lithium sulfur batteries: a review of recent progress and future directions
Authors: Akgenc Berna , Sarikurt Sevil , Yagmurcukardes Mehmet , Ersan Fatih
Published: April 2021

Advanced materials with various micro-/nanostructures have attracted plenty of attention for decades in energy storage devices such as rechargeable batteries (ion- or sulfur based batteries) and supercapacitors. To improve the electrochemical performance of batteries, it is uttermost important to develop advanced electrode materials. Moreover, the cathode material is also important that it restricts the efficiency and practical application of aluminum-ion batteries. Among the potential cathode materials, sulfur has become an important candidate material for aluminum-ion batteries cause of its considerable specific capacity. Two-dimensional materials are currently potential candidates as electrodes from lab-scale experiments to possible pragmatic theoretical studies. In this review, the fundamental principles, historical progress, latest developments, and major problems in Li–S and Al–S batteries are reviewed. Finally, future directions in terms of the experimental and theoretical applications have prospected.
Matching and reassignment based time-frequency enhancement for rotating machinery fault diagnosis under nonstationary speed operations
Authors: Hua Zehui , Shi Juanjuan , Jiang Xingxing , Luo Yang , Zhu Zhongkui
Published: April 2021

Time-frequency (TF) analysis (TFA) to nonstationary signals can reveal the nonlinearly changing instantaneous frequencies (IFs) of signals; it is, therefore, widely used for rotating machinery fault diagnosis under time-varying speed conditions. However, the traditional TFA methods may only reveal the outline of IFs due to the extra TF diffusion caused by limited TF resolution, hindering the fault diagnosis of rotating machinery. To enhance the readability of the time-frequency representation (TFR) of the signals with IF trajectories linearly time-varying, linear chirplet transform has been proved effective. To effectively tackle the signal with nonlinearly changing IFs, a string of chirp-rates is preferred, where the final TFR is obtained by superposition of each corresponding sub-TFR at each TF point. However, the extra cross-term interferences resulted from a string of chirp-rates cannot be neglected on TFRs. Aiming at alleviating the cross-terms from the TFR, matching and reassignment based TF enhancement strategy is proposed, where only the appropriate chirp-rate and its corresponding TFR slice is retained at each time instant. The appropriate chirp-rate is adaptively selected by the index—spectral kurtosis. To further increase the readability of the resulting TFR, a reassignment technique synchrosqueezing transform is integrated with the proposed matching strategy. By iteratively employing reassignments, TFR with the enhanced energy and sharp IF ridges can be generated. The effectiveness of the proposed method is validated by both simulated and experimental analyses. It is shown that the proposed method is effective in processing time-varying signals and can provide more accurate IF estimation, which paves the way for rotating machinery fault diagnosis under nonstationary speed conditions.
Structural evolution of Si-based anode materials during the lithiation reaction
Authors: Wang Zuozhang , Li Feng , Ding Wenyu , Tang Xianqiong , Xu Fu , Ding Yanhuai
Published: April 2021

Si-based materials have been intensively investigated as anode materials for Li-ion batteries. However, the structural evolution of the materials during the lithiation reaction is still unrevealed. In this paper, the structural parameters and mechanical properties of Si, SiO
x
(0 < x < 2) and SiO2 during the lithiation reaction are studied by first-principle calculation based on density functional theory. The relationship between the Li number and expansion coefficient, elastic constant, modulus, and Poisson’s ratio is systematically calculated.
Gas-solid interfacial charge transfer in volatile organic compound detection by CuCrO2 nanoparticles
Authors: Xu Sifan , Zhao Tingting , Kong Lingwei , Zhu Wenhuan , Bo Maolin , Huang Yizhong , Liu Hai
Published: April 2021

Nanostructured metal oxide semiconductors have received great attention used as the chemiresistive layer of gas sensor to detect the volatile organic compound recently. As indispensable complementary parts for dominative n-type semiconductors, the p-type metal oxides based gas sensors fail to be studied sufficiently, which hampers their practical applications. In this work, the p-type delafossite CuCrO2 nanoparticles were synthesized, characterized, and tested for gas sensing, followed by the first principles calculations to simulate the generation of chemiresistive signal. The hydrothermal synthesis time of CuCrO2 nanoparticles is optimized as 24 h with a higher proportion of oxygen vacancies but a smaller size, which is confirmed by the microscopy and spectrum characterization and allows for a prevailing gas sensitivity. Meanwhile, this CuCrO2 gas sensor is proven to perform a higher selectivity to n-propanol and a low detection limit of 1 ppm. The adsorption sites and charge variations of dehydrogenation at the gas-solid interface predicted by the theoretical analysis are claimed to be crucial to such selectivity. It is an innovative approach to understand the chemiresistive gas sensing by evaluating the preference of charge transfer between the sensor and target gaseous molecule, which provides a new route to precisely design and develop the advanced sensing devices for the diverse applications.
Reducing metal/graphene contact resistance via N, N-dimethylacetamide-assisted clean fabrication process
Authors: Zhu Chao-yi , Peng Song-ang , Zhang Xiao-rui , Yao Yao , Huang Xin-nan , Yan Yun-peng , Zhang Da-yong , Shi Jing-yuan , Jin Zhi
Published: April 2021

Contact resistance (R

C
) is of great importance for radio frequency (RF) applications of graphene, especially graphene field effect transistors (FETs) with short channel. FETs and transmission line model test structures based on chemical vapor deposition grown graphene are fabricated. The effects of employing traditional lithography solvent (Acetone) and strong solvents for photo resist, such as N, N-Dimethylacetamide (ZDMAC) and N-Methyl pyrrolidone (NMP), are systematically investigated. It was found that ZDMAC and NMP have more proficiency than acetone to remove the photo-resist residues and contaminations attached on graphene surface, enabling clean surface of graphene. However, strong solvents are found to destroy the lattice structure of graphene channel and induce defects in graphene lattice. Clean surface contributes to a significant reduction in the R

C
between graphene channel and metal electrode, and the defects introduced on graphene surface underneath metal electrodes also contribute the reduction of R

C
. But defects and deformation of lattice will increase the resistance in graphene channel and lead to the compromise of device performance. To address this problem, a mix wet-chemical approach employing both acetone and ZDMAC was developed in our study to realize a 19.07% reduction of R

C
, without an unacceptable mass production of defects.
On the origins of Riemann–Hilbert problems in mathematics*
Authors: Bothner Thomas
Published: April 2021

This article is firstly a historic review of the theory of Riemann–Hilbert problems with particular emphasis placed on their original appearance in the context of Hilbert’s 21st problem and Plemelj’s work associated with it. The secondary purpose of this note is to invite a new generation of mathematicians to the fascinating world of Riemann–Hilbert techniques and their modern appearances in nonlinear mathematical physics. We set out to achieve this goal with six examples, including a new proof of the integro-differential Painlevé-II formula of Amir et al (2011 Commun. Pure Appl. Math.
64 466–537) that enters in the description of the Kardar–Parisi–Zhang crossover distribution. Parts of this text are based on the author’s Szegő prize lecture at the 15th International Symposium on Orthogonal Polynomials, Special Functions and Applications (OPSFA) in Hagenberg, Austria.
Optimising use of 4D-CT phase information for radiomics analysis in lung cancer patients treated with stereotactic body radiotherapy
Authors: Davey Angela , van Herk Marcel , Faivre-Finn Corinne , Brown Sean , McWilliam Alan
Published: April 2021

Purpose. 4D-CT is routine imaging for lung cancer patients treated with stereotactic body radiotherapy. No studies have investigated optimal 4D phase selection for radiomics. We aim to determine how phase data should be used to identify prognostic biomarkers for distant failure, and test whether stability assessment is required. A phase selection approach will be developed to aid studies with different 4D protocols and account for patient differences. Methods. 186 features were extracted from the tumour and peritumour on all phases for 258 patients. Feature values were selected from phase features using four methods: (A) mean across phases, (B) median across phases, (C) 50% phase, and (D) the most stable phase (closest in value to two neighbours), coined personalised selection. Four levels of stability assessment were also analysed, with inclusion of: (1) all features, (2) stable features across all phases, (3) stable features across phase and neighbour phases, and (4) features averaged over neighbour phases. Clinical-radiomics models were built for twelve combinations of feature type and assessment method. Model performance was assessed by concordance index (c-index) and fraction of new information from radiomic features. Results. The most stable phase spanned the whole range but was most often near exhale. All radiomic signatures provided new information for distant failure prediction. The personalised model had the highest c-index (0.77), and 58% of new information was provided by radiomic features when no stability assessment was performed. Conclusion. The most stable phase varies per-patient and selecting this improves model performance compared to standard methods. We advise the single most stable phase should be determined by minimising feature differences to neighbour phases. Stability assessment over all phases decreases performance by excessively removing features. Instead, averaging of neighbour phases should be used when stability is of concern. The models suggest that higher peritumoural intensity predicts distant failure.
Display-pixel performances driven by contact-limited switching transistors
Authors: Lee Seunghyuk , Kim Chang-Hyun
Published: April 2021

In this paper, a direct link between contact properties of the transistor and electrical behaviors of the display system is established. Employing a liquid-crystal display driven by organic thin-film transistors as a model platform, systematic simulation of the image pixel circuit is performed to investigate this critical relationship. An elevated contact resistance at the transistor level is found to have a profound impact on charging dynamics of cell capacitors, revealing the importance of rendering such effects in designing advanced display electronics.
Influence of a compressive strain on the high-temperature thermoelectric properties of europium orthoferrite
Authors: Carlos III Baldo , Rajan P Iyyappa , Mahalakshmi S , Ramalingam R Jothi
Published: April 2021

Promising high temperature thermoelectric (TE) potential of europium orthoferrite (EuFeO3) is methodically investigated in this work, wherein the focus is on the influence of a −3% compressive strain on scattering rates and on transport properties. Using Boltzmann transport theory, transport properties such as Seebeck coefficient S, electrical conductivity σ, electronic thermal conductivity κ
e and power factor (PF) are obtained with appropriate regard to the prevailing scattering mechanisms present in the materials that affect its electronic transport. Here, we find that polar optical phonon (POP) scattering is the dominant scattering potential affecting the TE properties of EuFeO3 for temperatures from 900 K to 1500 K. The incorporation of a −3% compressive strain suppresses the POP scattering, as evidenced by the decrease in its scattering rates. This result consequently enhances the lattice thermal conductivity κ
L—which then has negative impact to the TE efficiency. Nevertheless, we find that the strain largely improves the σ of EuFeO3, and the PF as well. Unstrained p-type EuFeO3 registers remarkable values of PF equal to 167 μW m−1 K−2 at 900 K and 97.7 μW m−1K−2 at 1500 K for when the hole concentration is 1021 cm−3. Under a −3% compressive strain, the PF rises to almost double at 294 μW m−1 K−2 for 900 K and 170 μW m−1 K−2 for 1500 K for the same doping value. Finally, we believe that the methodology and discussions presented in this work well deliver a template relevant in modeling materials fit for high-temperature TE applications.
Jerky active matter: a phase field crystal model with translational and orientational memory
Authors: te Vrugt Michael , Jeggle Julian , Wittkowski Raphael
Published: April 2021

Most field theories for active matter neglect effects of memory and inertia. However, recent experiments have found inertial delay to be important for the motion of self-propelled particles. A major challenge in the theoretical description of these effects, which makes the application of standard methods very difficult, is the fact that orientable particles have both translational and orientational degrees of freedom which do not necessarily relax on the same time scale. In this work, we derive the general mathematical form of a field theory for soft matter systems with two different time scales. This allows to obtain a phase field crystal model for active particles with translational and orientational memory. Notably, this theory is of third order in temporal derivatives and can thus be seen as a spatiotemporal jerky dynamics. We obtain the phase diagram of this model, which shows that, unlike in the passive case, the linear stability of the liquid state depends on the damping coefficients. Moreover, we investigate sound waves in active matter. It is found that, in active fluids, there are two different mechanisms for sound propagation. For certain parameter values and sufficiently high frequencies, sound mediated by polarization waves experiences less damping than usual passive sound mediated by pressure waves of the same frequency. By combining the different modes, acoustic frequency filters based on active fluids could be realized.
Insights on magnon topology and valley-polarization in 2D bilayer quantum magnets
Authors: Ghader Doried
Published: April 2021

The rich and unconventional physics in layered 2D magnets can open new avenues for topological magnonics and magnon valleytronics. In particular, two-dimensional (2D) bilayer quantum magnets are gaining increasing attention due to their intriguing stacking-dependent magnetism, controllable ground states, and topological excitations induced by magnetic spin–orbit couplings (SOCs). Despite the substantial research on these materials, their topological features remain widely unexplored to date. The present study comprehensively investigates the magnon topology and magnon valley-polarization in honeycomb bilayers with collinear magnetic order. We elucidate the separate and combined effects of the SOC, magnetic ground-states, stacking order, and inversion symmetry breaking on the topological phases, magnon valley transport, and the Hall and Nernst effects. The comprehensive analysis suggests clues to determine the SOC’s nature and predicts unconventional Hall and Nernst conductivities in topologically trivial phases. We further report on novel bandgap closures in layered antiferromagnets and detail their topological implications. We believe the present study provides important insights into the fundamental physics and technological potentials of topological 2D magnons.
Orbital Solutions of the New Low-mass Eclipsing Binary TIC 157376469 with Spotted Activities
Authors: Pan Yang , Fu Jian-Ning , Zhang Xiaobin , Wang Jiaxin , Zong Weikai , Li Chunqian , Zhang Bo
Published: April 2021

We carried out a photometric and spectroscopic analysis for the eclipsing binary TIC 157376469 using the TESS and LAMOST data. A new linear ephemeris is given. By fitting the light curves and radial velocity curves with the Wilson–Devinney code, it apperas that the binary is composed of two K-type main-sequence stars. The orbit of the binary is slightly eccentric (

e
≈
0.0017

) and the primary is a spotted active star. The masses and radii of the two components are determined to be

M

1

=
0.704
±
0.028

M

⊙

,

R

1

=
0.754
±
0.010

R

⊙

,

M

2

=
0.539
±
0.021

M

⊙

,

R

2

=
0.543
±
0.007

R

⊙

, respectively. The temperature ratio (

T

2

/

T

1

) is determined to be ∼0.879. Under a assumption that the primary temperature is

T

1

=
4740
K

, comparisons to the PARSEC v1.2 isochrones show that for the primary the radius is oversized of ∼16%, and the effective temperature is cooler of

∼
300
K

(∼6%). While, the properties of the secondary are almost in agreement with the predictions of the model.
Stable self-pulsing regime in a Brillouin ring fiber laser cavity
Authors: Silva Luís C B , Marques Carlos A F , Segatto Marcelo E V , Pontes Maria J
Published: April 2021

This study reports that when solving by full integration a set of coupled ordinary differential equations that describe the spatial evolution of the guided pump and Stokes powers caused by stimulated Brillouin scattering in the regime of pump depletion, a structure of regular pulses emerge from the output of a Brillouin laser cavity characterized as a stable self-pulsing regime. The dependence of this self-pulsing mechanism on the laser cavity length, the coupling factor, and the pump power is investigated revealing the existence of three regimes: no lasing, continuous, and self-pulsing. When compared to records in the scientific literature, this is the first time, to the best of the author’s knowledge, that a stable self-pulsing regime is reported theoretically. Furthermore, we also demonstrated the pumping depletion during the formation of the self-pulsing regime. These results provide not only a better understanding of the dynamics of self-pulsing regimes in a fiber laser cavity but also the possibility of unlocking the mechanisms responsible for the formation of stable pulse trains in a Brillouin fiber-ring laser.
Multiform description of the AKNS hierarchy and classical r-matrix
Authors: Caudrelier Vincent , Stoppato Matteo
Published: April 2021

In recent years, new properties of space-time duality in the Hamiltonian formalism of certain integrable classical field theories have been discovered and have led to their reformulation using ideas from covariant Hamiltonian field theory: in this sense, the covariant nature of their classical r-matrix structure was unravelled. Here, we solve the open question of extending these results to a whole hierarchy. We choose the Ablowitz–Kaup–Newell–Segur (AKNS) hierarchy. To do so, we introduce for the first time a Lagrangian multiform for the entire AKNS hierarchy. We use it to construct explicitly the necessary objects introduced previously by us: a symplectic multiform, a multi-time Poisson bracket and a Hamiltonian multiform. Equipped with these, we prove the following results: (i) the Lax form containing the whole sequence of Lax matrices of the hierarchy possesses the rational classical r-matrix structure; (ii) the zero curvature equations of the AKNS hierarchy are multiform Hamilton equations associated to our Hamiltonian multiform and multi-time Poisson bracket; (iii) the Hamiltonian multiform provides a way to characterise the infinite set of conservation laws of the hierarchy reminiscent of the familiar criterion {I, H} = 0 for a first integral I.
Passive amplitude-phase modulations and sensing based on Mach–Zehnder interferometer of spoof surface plasmon polaritons
Authors: Cui Wen Yi , Zhang Jingjing , Gao Xinxin , Zhang Xuanru , Cui Tie Jun
Published: April 2021

We numerically and experimentally demonstrate an ultrathin and compact Mach–Zehnder interferometer (MZI) for sensing and amplitude/phase modulations of spoof surface plasmon polariton (SSPP) waves. For a specific frequency, the magnitude and phase of the far-field transmission are modulated when a dielectric sample is loaded on one of the MZI arms. The phase difference between the SSPP waves propagating along the sensing and reference arms causes the outputs from both arms to interfere, allowing small perturbations in the sensing arm to be detected. Our study shows that the sensitivity of the proposed SSPP MZI is significantly higher than that of the single-armed SSPP waveguide, and also better than that of the conventional MZI formed with the traditional microstrip lines. The dependence of the sensitivity on the structural parameters such as geometrical parameters of the detected material and the arm length of MZI is discussed, revealing the possibility of realizing miniaturized MZI with high sensitivity.
Extension and validation of a revised Cassie-Baxter model for tailor-made surface topography design and controlled wettability
Authors: Lempesis Nikolaos , Koopmans Rudolf J , Díez-Ahedo Ruth , Kristiansen Per Magnus
Published: April 2021

Predicting wettability accurately across various materials, surface topographies and wetting liquids is undeniably of paramount importance as it sets the foundations for technological developments related to improved life quality, energy saving and economization of resources, thereby reducing the environmental impact for recycling and reuse. In this work, we extend and validate our recently published wetting model, constituting a refinement of the original Cassie-Baxter model after consideration of realistic curved liquid-air interfaces. Our model enabled more meaningful contact angle predictions, while it captured the experimentally observed trends between contact angle and surface roughness. Here, the formalism of our wetting model is further extended to 3D surface topographies, whereas the validity of our model, in its entirety, is evaluated. To this end, a total of thirty-two experimentally engineered surfaces of various materials exhibiting single- and multilevel hierarchical topographies of increasing complexity were utilized. Our model predictions were consistently in remarkable agreement with experimental data (deviations of 3%–6%) and, in most cases, within statistical inaccuracies of the experimental measurements. Direct comparison between experiments and modeling results corroborated that surface topographies featuring re-entrant geometries promoted enhanced liquid-repellency, whereas hierarchical multilevel surface topographies enabled even more pronounced nonwetting behaviors. For the sinusoidal topography, consideration of a second superimposing topography level almost doubled the observed water contact angles, whereas addition of a third level brought about an extra 12.5% increase in water contact angle.
Achieving a quantum smart workforce
Authors: Aiello Clarice D , Awschalom D D , Bernien Hannes , Brower Tina , Brown Kenneth R , Brun Todd A , Caram Justin R , Chitambar Eric , Di Felice Rosa , Edmonds Karina Montilla , Fox Michael F J , Haas Stephan , Holleitner Alexander W , Hudson Eric R , Hunt Jeffrey H , Joynt Robert , Koziol Scott , Larsen M , Lewandowski H J , McClure Doug T , Palsberg Jens , Passante Gina , Pudenz Kristen L , Richardson Christopher J K , Rosenberg Jessica L , Ross R S , Saffman Mark , Singh M , Steuerman David W , Stark Chad , Thijssen Jos , Vamivakas A Nick , Whitfield James D , Zwickl Benjamin M
Published: April 2021

Interest in building dedicated quantum information science and engineering (QISE) education programs has greatly expanded in recent years. These programs are inherently convergent, complex, often resource intensive and likely require collaboration with a broad variety of stakeholders. In order to address this combination of challenges, we have captured ideas from many members in the community. This manuscript not only addresses policy makers and funding agencies (both public and private and from the regional to the international level) but also contains needs identified by industry leaders and discusses the difficulties inherent in creating an inclusive QISE curriculum. We report on the status of eighteen post-secondary education programs in QISE and provide guidance for building new programs. Lastly, we encourage the development of a comprehensive strategic plan for quantum education and workforce development as a means to make the most of the ongoing substantial investments being made in QISE.
Dispersive readout of room-temperature ensemble spin sensors
Authors: Ebel J , Joas T , Schalk M , Weinbrenner P , Angerer A , Majer J , Reinhard F
Published: April 2021

We demonstrate dispersive readout of the spin of an ensemble of nitrogen-vacancy centers in a high-quality dielectric microwave resonator at room temperature. The spin state is inferred from the reflection phase of a microwave signal probing the resonator. Time-dependent tracking of the spin state is demonstrated, and is employed to measure the T
1 relaxation time of the spin ensemble. Dispersive readout provides a microwave interface to solid state spins, translating a spin signal into a microwave phase shift. We estimate that its sensitivity can outperform optical readout schemes, owing to the high accuracy achievable in a measurement of phase. The scheme is moreover applicable to optically inactive spin defects and it is non-destructive, which renders it insensitive to several systematic errors of optical readout and enables the use of quantum feedback.
Arbitration: A Very Short Introduction
Authors: Schultz Thomas , Grant Thomas
Published: April 2021

Arbitration: A Very Short Introduction explains what arbitration is, how it works, what parties who have agreed to go to arbitration should expect, the relationship between arbitration and the law, and the politics of arbitration. Arbitration is a legal dispute resolution mechanism, providing binding decisions which are enforceable around the world. It is where parties take their disputes when they have agreed that courts, for one reason or another, do not suit them. Some of the most politically sensitive disputes on the largest scale go to arbitration. But also much smaller, everyday cases are routinely dealt with by arbitration. This VSI considers where the global system of arbitration is headed.
Coral Reefs: A Very Short Introduction
Authors: Sheppard Charles
Published: April 2021

Reefs and the coral life that builds them were for centuries a source of mystery to naturalists and hazard to seafarers. Many ideas were developed of what built them and why they all existed so close to sea level but never above it. Darwin developed the theory of how they were built, which was proven a century later. The coral polyp is central to each coral colony and to the reef. Each houses countless symbiotic algal cells that provide the energy that supports the coral reef ecosystem, and the energy needed to extract minerals from seawater to deposit as solid limestone. These are the ocean’s most biodiverse ecosystem. The islands perched on them include many entire nations, and reefs provide land, food, and protection to these as well as parts of many others. The diversity and abundance of other species, from microbial systems that are key to nutrient and energy transfer, to the large predatory fish, are similarly vast, and various components of the reef system have been researched intensively since the advent of scuba techniques. Today, however, local impacts and pressures from pollution to overfishing have degraded and damaged many, and more recently, warming of ocean water resulting from climate change is causing an existential threat to the survival of this rich ecosystem. Arresting the decline is no longer a scientific problem but one for society and governments, and failure to do so will result, indeed already is, in untold damage to human societies that depend on coral reefs.
Mitochondrial DNA as a Molecular Marker in Insect Ecology: Current Status and Future Prospects
Authors: Dong Zhaoke , Wang Yangzhou , Li Chao , Li Lili , Men Xingyuan
Published: April 2021

Molecular techniques are powerful tools that can address many research problems in insect ecology. Mitochondrial DNA (mtDNA) is a widely used molecular marker. It is easy to use and has favorable biological properties, such as near-neutrality, lack of recombination, and a clock-like evolutionary rate. However, there are some issues involved when using mtDNA data in population genetics, species delimitation, and estimating the evolutionary history of populations and species. Exceptions to the simplicity of mitochondrial inheritance and other limitations include small effective population sizes, maternal inheritance, and complex evolutionary processes. Combining mtDNA and nuclear DNA markers can improve the power of molecular data to test phylogenetic and phylogeographic hypotheses. We review the applications of mtDNA in insect ecology and conclude that a better understanding of the properties of mitochondria is essential for the application of mtDNA.
The Question of Comparison
Authors: Petretta Ida
Published: April 2021

Comparison is a key component of legal reasoning. We move merrily from like to like within the doctrine of precedent. We invoke comparison whenever we distinguish or apply a case. This Article begins by elucidating how comparison is present in law. The Article shows how law cannot function without comparison, and how the legal world skips over the central role comparison plays in these matters. The Article explores the literature on legal comparison and draws on insights from philosophy, comparative law, and anthropology to better understand comparison in practice. This Article argues that while we are entangled in the questions of sameness and difference, of finding the function and tying together, we are still not asking the question of comparison. What is function and how is it related to comparison? Inspired by James Tully’s writings, the Article explores the aspectival views of the legal world suggested by the different games of comparison. The Article draws on Stephen Mulhall’s work on Wittgenstein’s seeing as, aspect dawning, and aspect blindness to further ask about our relationship to comparison. The Article shows how mainstream comparisons are ontic comparisons that think togetherness through the comparatist. The comparatist steers the belonging together and (un)makes the meaning of all things in mainstream comparison. The argument builds on earlier work by Igor Stramignoni, showing how the Western legal tradition is within a kind of Heideggerian calculative thinking. The Article explores the possibility of other kinds of comparison through Stramignoni’s poetic comparisons. This Article calls on us to slow down our comparisons and begin to question comparison itself.
Is Protestant Interpretation an Acceptable Attitude Toward Normative Social Practices? An Analysis of Dworkin and Postema
Authors: Bustamante Thomas
Published: April 2021

Gerald Postema raised a powerful challenge to Ronald Dworkin’s theory of interpretation. By allowing each interpreter to make her own judgment about the content of a social norm, Dworkinian interpretation becomes insufficiently intersubjective and insufficiently political. In previous work, I argued that this criticism must be rejected because Postema’s own account of law, analogical reasoning, and the rule of law requires one to make a reflected judgment and hold other actors accountable to the law. Nevertheless, a powerful objection claims that protestant interpretation is incompatible with the first person-plural reasoning that an intersubjective social practice requires. In response to the objection, I argue that no such incompatibility exists. On closer examination, protestant interpretation is part of the attitude that a rational agent must adopt if she is to acquit her moral responsibilities as a participant in a social practice.
Estimating Historical Exposure to Respirable Crystalline Silica in the Mining Industry in Ontario, Canada Using a Newly Developed Exposure Database
Authors: Blagrove-Hall Nicola , Berriault Colin , Jardine Katherine J , Demers Paul A , Arrandale Victoria H
Published: April 2021

Objectives

To use the recently developed Ontario Mining Exposure Database (OMED) to describe historical silica exposure in the Ontario metal mining industry and identify predictors of historical silica exposure.

Methods

Personal respirable crystalline silica (RCS) data for metal mines were extracted from OMED and included both individual and summary measures, where multiple exposure measurements (n > 1) were aggregated and entered as a single exposure value (n = 1). Data were stratified by sample location (underground/surface) for analysis. Monte Carlo simulation was used to simulate individual measures from the summary measures. A fixed effects multiple linear regression model was used to assess the effects of commodity (ore mined), sample year, source of exposure data, and occupational group on RCS concentration. Parameter estimates (β), standard errors, and 95% upper and lower confidence intervals were reported.

Results

The OMED contained 12 995 silica measurements. After limiting to RCS measurements in metal mines, and measures with sufficient information for analysis, 2883 RCS measurements collected from 1974 to 1991 remained, including 2816 individual and 67 summary measurements. In total, 321 individual RCS measurements were simulated from the 67 summary measures. The analysis database contained 2771 (12% simulated) underground measurements and 366 surface measurements (0% simulated). In the underground group, an overall geometric mean (GM) of 0.05 [geometric standard deviation (GSD) 3.09] mg m−3 was estimated with a 6% annual decrease over time. In this group, the commodity with the highest average RCS level was zinc mines (GM = 0.07 mg m−3) and the lowest was iron mines (GM = 0.01 mg m−3). In the surface group, an overall GM of 0.05 (GSD 3.70) mg m−3 was estimated with an 8% decreased over time. In this group, the commodity with the highest average RCS level was gold mines (GM = 0.07 mg m−3) and the lowest was zinc mines (GM = 0.03 mg m−3). In both groups, company collected data had lower estimated RCS compared with regulator collected data.

Conclusions

Historical RCS levels decreased over time. Mean measurements exceeded the American Conference of Governmental Industrial Hygienists current health-based threshold limit value (0.025 mg m−3). The main predictors of exposure were commodity, source of exposure data, and sample year. However, low R2 and high GSD values suggest additional predictors of RCS exposures in Ontario’s metal mines exist that were unavailable in OMED.
Identifying Risks for Persistent Postconcussive Symptoms in a Pediatric Emergency Department: An Examination of a Clinical Risk Score
Authors: Root J M , Gai J , Sady M D , Vaughan C G , Madati P J
Published: April 2021

Objective

External examination of a clinical risk score to predict persistent postconcussive symptoms (PPCS) in a pediatric emergency department (ED).

Methods

Prospective cohort study of 5- to 18-year-old patients diagnosed with an acute concussion. Risk factors were collected at diagnosis and participants (n = 85) were followed to determine PPCS 30 days postinjury. Univariate logistic regression analyses were completed to examine associations of risk factors with PPCS.

Results

Headache and total clinical risk score were associated with increased odds of PPCS in the univariate analyses, OR 3.37 (95% CI 1.02, 11.10) and OR 1.25 (95% CI 1.02, 1.52), respectively. Additionally, teenage age group, history of prolonged concussions, and risk group trended toward association with PPCS, OR 4.79 (95% CI 0.93, 24.7), OR 3.41 (95% CI 0.88, 13.20), and OR 2.23 (95% CI 0.88, 5.66), respectively.

Conclusion

Our study supports the use of multiple variables of a clinical risk score to assist with ED risk stratification for pediatric patients at risk for PPCS.
Acoustic and visual stimuli combined promote stronger responses to aerial predation in fish
Authors: Lukas Juliane , Romanczuk Pawel , Klenz Haider , Klamser Pascal , Arias Rodriguez Lenin , Krause Jens , Bierbach David
Published: April 2021

Bird predation poses a strong selection pressure on fish. Since birds must enter the water to catch fish, a combination of visual and mechano-acoustic cues (multimodal) characterize an immediate attack, while single cues (unimodal) may represent less dangerous disturbances. We investigated whether fish could use this information to distinguish between non-threatening and dangerous events and adjust their antipredator response to the perceived level of risk. To do so, we investigated the antipredator behavior of the sulphur molly (Poecilia sulphuraria), a small freshwater fish which is almost exclusively preyed on by piscivorous birds in its endemic sulfide spring habitat. In a field survey, we confirmed that these fish frequently have to distinguish between disturbances stemming from attacking birds (multimodal) and those which pose no (immediate) threat such as bird overflights (unimodal). In a laboratory experiment, we then exposed fish to artificial visual and/or acoustic stimuli presented separately or combined. Sensitivity was high regardless of stimulus type and number (more than 96% of fish initiated diving), but fish dove deeper, faster, and for longer when both stimuli were available simultaneously. Based on the system’s high rates of bird activity, we argue that such an unselective dive initiation with subsequent fine-tuning of diving parameters in accordance to cue modality represents an optimal strategy for these fish to save energy necessary to respond to future attacks. Ultimately, our study shows that fish anticipate the imminent risk posed by disturbances linked to bird predation through integrating information from both visual and acoustic cues.
Artificial light at night alters activity, body mass, and corticosterone level in a tropical anuran
Authors: Secondi Jean , Mondy Nathalie , Gippet Jérôme Marcel Walter , Touzot Morgane , Gardette Vanessa , Guillard Ludovic , Lengagne Thierry
Published: April 2021

Photoperiod is a major factor regulating biological rhythms in animals and plants. At low latitudes, annual variation in daylength is low and species are expected to strongly rely on photic cues to reset their circadian clocks. A corollary is that individuals should be strongly affected by sudden changes in the photic regime as those generated by artificial light at night (ALAN). We tested this hypothesis in an anuran in Costa Rica (10°N). Using an outdoor experimental design, we exposed adult cane toads Rhinella marina, a broadly distributed tropical anuran species to two ALAN intensities (0.04 and 5 lx). Locomotor activity was reduced at the lowest intensity, and the activity pattern shifted from crepuscular to nocturnal. Contrary to humans and mice in which ALAN favor obesity, toads from the two exposed groups did not gain mass whereas controls did. Corticosterone was reduced at the highest intensity, a possible consequence of the reduced activity of toads or the altered regulation of their circadian pattern. Thus, the behavioral and physiological disruption that we observed supports the hypothesis of the strong reliance on photic cues to regulate circadian rhythms and control homeostasis in this intertropical anuran. Furthermore, our results suggest that the negative effects of ALAN on physiology, in particular body mass regulation, may differ between vertebrate groups, thus preventing anticipated generalization before more comparative studies have been carried out. We stress the importance of considering the impact of the changing nocturnal environment in the intertropical zone which host the largest fraction of biodiversity.