bluuebunny/crossref_metadata_2025 huggingface dataset:
Privacy versus Convenience: A Historical Perspective, Analysis of Risks, and an Informatics Call to Action
Authors: Ozeran Larry , Solomonides Anthony , Schreiber Richard
Published: May 2021

Background The pace of technological change dwarfs the pace of social and policy change. This mismatch allows for individual harm from lack of recognition of changes in societal context. The value of privacy has not kept pace with changes in technology over time; individuals seem to discount how loss of privacy can lead to directed personal harm.

Objective The authors examined individuals sharing personal data with mobile health applications (mHealth apps) and compared the current digital context to the historical context of harm. The authors make recommendations to informatics professionals to support consumers who wish to use mHealth apps in a manner that balances convenience with personal privacy to reduce the risk of harm.

Methods A literature search focused by a historical perspective of risk of harm was performed throughout the development of this paper. Two case studies highlight questions a consumer might ask to assess the risk of harm posed by mobile health applications.

Results A historical review provides the context for the collective human experience of harm. We then encapsulate current perceptions and views of privacy and list potential risks created by insufficient attention to privacy management.

Discussion The results provide a historical context for individuals to view the risk of harm and shed light on potential emotional, reputational, economic, and physical harms that can result from naïve use of mHealth apps. We formulate implications for clinical informaticists.

Conclusion Concepts of both harm and privacy have changed substantially over the past 20 years. Technology provides methods to invade privacy and cause harm unimaginable a few decades ago. Only recently have the consequences become clearer. The current regulatory framework is extremely limited. Given the risks of harm and limited awareness, we call upon informatics professionals to support more privacy education and protections and increase mHealth transparency about data usage.
Stabilization and manipulation of in-plane polarization in a ferroelectric|dielectric superlattice
Authors: Strkalj Nives , Bernet Marco , Sarott Martin F. , Schaab Jakob , Weber Thomas , Fiebig Manfred , Trassin Morgan
Published: May 2021

We investigate in-plane ferroelectricity in an epitaxial ferroelectric|dielectric PbTiO3|SrTiO3 (PTO|STO) superlattice under tensile strain. Using a combination of x-ray diffraction and piezoresponse force microscopy, we identify a strain-induced periodic in-plane nanoscale domain architecture with polarization along the base diagonals of the PTO unit cell. We scrutinize its switching behavior using local in-plane trailing fields from the scanning-probe tip. For an electric field pointing in the polarization direction of a specific domain state, we create stable single-domain areas of in-plane polarization at the scale of tens of micrometers. Our findings on controlling robust in-plane ferroelectricity in ultrathin ferroelectric layers can help one to develop device concepts unaffected by the detrimental effects of the depolarizing field.
On the concept of energized mass: A robust framework for low-order force modeling in flow past accelerating bodies
Authors: Galler Joshua N. , Weymouth Gabriel D. , Rival David E.
Published: May 2021

The concept of added (virtual) mass is applied to a vast array of unsteady fluid-flow problems; however, its origins in potential-flow theory may limit its usefulness in separated flows. A robust framework for modeling instantaneous fluid forces is proposed, named Energized Mass. The energized-mass approach is tested experimentally by acquiring the fluid kinetic-energy history around an accelerating sphere at both subcritical and supercritical terminal velocities. By tracking the energized-mass volume, the force response is shown to be related to changes in shear-layer growth as a function of acceleration moduli and Reynolds number. The energized-mass framework is then used to develop a low-order force model, requiring only body geometry and kinematics as input. An analytical expression for the instantaneous force on a sphere due to energized-mass growth is derived based on shear-layer mass flux arguments. Instantaneous forces determined experimentally, and modeled using the energized-mass approach, show strong agreement with direct force measurements. The results of this investigation thus demonstrate that the energized-mass framework provides a viable low-order modeling approach, and in tandem, can provide new insights into the origin of forces on accelerating bodies.
Suppression of ITG turbulence due to spectral shift during biasing induced H-mode on HBT-EP
Authors: Stewart I. G. , Brooks J. W. , Levesque J. P. , Mauel M. E. , Navratil G. A.
Published: May 2021

Investigations of biasing induced H-mode discharges on HBT-EP show that the edge turbulence is consistent with the ion temperature gradient) mode and have allowed for the controlled observation of the effect of applied flow shear on the turbulence. Measurements of the radial wavenumber spectrum of floating potentials at the edge show that the turbulence intensity decreases with increasing shift in the spectrum average ⟨kr⟩ when increasing amounts of bias probe voltage (and increasing amounts of flow shear) is applied. This is in agreement with the spectral shift model [Staebler et al., Phys. Rev. Lett. 110, 055003 2013] for turbulence suppression via sheared flow. A shift in the wavenumber spectrum occurs at applied electrode voltages and currents below the threshold needed for an L–H transition, and a dithering transition is obtained when biasing near the threshold. Suppression of blob-filament turbulence in the scrape-off layer (SOL) precedes the L–H transition, with the SOL turbulence remaining low throughout the dithering phase, despite the modulation of turbulence levels in the nearby edge. This demonstrates that the SOL turbulence “decouples” from the edge turbulence. The spectral shift in the measured radial wavenumber is corroborated by the direct measurement of eddy tilt angle using a novel time delay analysis technique first developed for Doppler reflectometry [Pinzón et al., Plasma Phys. Controlled Fusion 61, 105009 (2019)] but adapted here for floating potential measurements.
X-ray imaging of Rayleigh–Taylor instabilities using Fresnel zone plate at the National Ignition Facility
Authors: Do A. , Angulo A. M. , Hall G. N. , Nagel S. R. , Izumi N. , Kozioziemski B. J. , McCarville T. , Ayers J. M. , Bradley D. K.
Published: May 2021

Being able to provide high-resolution x-ray radiography is crucial in order to study hydrodynamic instabilities in the high-energy density regime at the National Ignition Facility (NIF). Current capabilities limit us to about 20 μm resolution using pinholes, but recent studies have demonstrated the high-resolution capability of the Fresnel zone plate optics at the NIF, measuring 2.3 μm resolution. Using a zinc Heα line at 9 keV as a backlighter, we obtained a radiograph of Rayleigh–Taylor instabilities with a measured resolution of under 3 μm. Two images were taken with a time integrated detector and were time gated by a laser pulse duration of 600 ps, and a third image was taken with a framing camera with a 100 ps time gate on the same shot and on the same line of sight. The limiting factors on image quality for these two cases are the motion blur and the signal to noise ratio, respectively. We also suggest solutions to increase the image quality.
Measurement of density profile and fluctuations using a multi-channel terahertz solid-state interferometer system on Keda Torus eXperiment (KTX)
Authors: Mao Wenzhe , Wang Xingkang , Zu Yiming , Xie Jinlin , Lan Tao , Li Hong , Liu Adi , Zhou Chu , Yuan Peng , Zheng Jian , Lian Hui , Liu Wandong , Ding Weixing
Published: May 2021

A five-chord interferometer based on terahertz solid state sources has been successfully installed on the Keda Torus eXperiment (KTX), a reversed field pinch machine. The optical design has been carefully optimized for the uniform distribution of beam light to fully use the limited power source (∼2 mW). By setting the telescopic mirror unit, the beam waist is located in the center of the vacuum vessel and its diameter is in the range of the Rayleigh length. The beam width across the plasma area is improved to ∼20 mm to minimize crosstalk and beam energy loss. After careful beam alignment, the phase noise for each channel can reach 0.004π. The radial profiles of electron density on the KTX are inverted, and density fluctuation associated with instabilities is shown based on the forward-scattering signals.
Multifunctional operation of the double-layer ferromagnetic structure coupled by a rectangular nanoresonator
Authors: Roberjot Pierre , Szulc Krzysztof , Kłos Jarosław W. , Krawczyk Maciej
Published: May 2021

The use of spin waves as a signal carrier requires developing the functional elements allowing for multiplexing and demultiplexing information coded at different wavelengths. For this purpose, we propose a system of thin ferromagnetic layers dynamically coupled by a rectangular ferromagnetic resonator. We show that single and double, clockwise and counterclockwise, circulating modes of the resonator offer a wide possibility of control of propagating waves. Particularly, at frequency related to the double-clockwise circulating spin-wave mode of the resonator, the spin wave excited in one layer is transferred to the second one where it propagates in the backward direction. Interestingly, the wave excited in the second layer propagates in the forward direction only in that layer. This demonstrates add-drop filtering and circulator functionality. Thus, the proposed system can become an important part of future magnonic technology for signal routing.
Electrical generation of visible surface plasmon polaritons by a nanopillars antenna array
Authors: Zhang Cheng , Hugonin Jean-Paul , Coutrot Anne-Lise , Vest Benjamin , Greffet Jean-Jacques
Published: May 2021

Electrical excitation of surface plasmon polaritons by inelastic tunneling electrons has been put forward as a potential nanosource that can be used in a variety of on-chip optoelectronic applications. In this article, we report a source based on an array of gold cylindrical antennas deposited on an alumina tunnel junction. This configuration has several merits: the junction can be operated under a high bias (>3 V) so that surface plasmons can be emitted in the visible region at room temperature; the antenna controls the surface plasmon emission spectrum; the radiative power per unit area is enhanced by more than two orders of magnitude compared to a planar junction.
Single-pixel camera with a large-area microstrip superconducting single photon detector on a multimode fiber
Authors: Shcherbatenko M. , Elezov M. , Manova N. , Sedykh K. , Korneev A. , Korneeva Yu. , Dryazgov M. , Simonov N. , Feimov A. , Goltsman G. , Sych D.
Published: May 2021

High sensitivity imaging at the level of single photons is an invaluable tool in many areas, ranging from microscopy to astronomy. However, development of single-photon sensitive detectors with high spatial resolution is very non-trivial. Here we employ the single-pixel imaging approach and demonstrate a proof-of-principle single-pixel single-photon imaging setup. We overcome the problem of low light gathering efficiency by developing a large-area microstrip superconducting single photon detector coupled to a multi-mode optical fiber interface. We show that the setup operates well in the visible and near infrared spectrum, and is able to capture images at the single-photon level.
Numerical analysis of two-phase flow in heterogeneous porous media during pre-flush stage of matrix acidizing: Optimization by response surface methodology
Authors: Sabooniha Ehsan , Rokhforouz Mohammad-Reza , Kazemi Alireza , Ayatollahi Shahab
Published: May 2021

Oil trapping behavior during the pre-flush stage is critically important to evaluate the effectiveness of matrix acidizing for the oil well stimulation. In this study, the visco-capillary behavior of the two-phase flow in the pore-scale is analyzed to investigate the influence of wetting properties for a natural rock sample. A two-dimensional model, based on Cahn–Hilliard phase-field and Navier–Stokes equations, was established and solved using the finite element method. A stability phase diagram for log capillary number (Ca)–log viscosity ratio (M) was constructed and then compared with the reported experimental works. The maximum and minimum ranges of capillary number and viscosity ratio to identify both viscous and capillary fingering regions were found to be Log M ≈ −2.5, Log Ca ≈ −5, and Log M ≈ −0.5, Log Ca ≈ −5, respectively. However, the most stable displacement region was found to be located at Log M ≈ 0.5 and Log Ca ≈ −2. Furthermore, the impact of four independent variables, including pore volume of injection (1 < PV < 5), capillary number (−6 < Log Ca < 0), viscosity ratio (−5 < Log M < 2), and contact angle (π/6<θ<5π/6), on recovery factor (RF) was investigated using central composite design of response surface methodology. For the chosen range of independent variables, the optimum conditions for the immiscible two-phase flow (e.g., RF > 0.95) occurred at Log M > 0, −4.5 < Log Ca < −2, PV > 1, θ > π/6 condition. It is worth mentioning that for Log M< 0, the optimum condition occurred at Log M ≈ 0, Log Ca ≈ −3.5, PV ≈ 4, and θ ≈ π/6.
Dynamics of rigid particles in a confined flow of viscoelastic and strongly shear-thinning fluid at very small Reynolds numbers
Authors: Hazra S. , Nath A. , Mitra S. K. , Sen A. K.
Published: May 2021

Despite growing interest in the focusing and manipulation of particles in non-Newtonian fluids in confined flows, the combined effect of viscoelastic and shear-thinning effects on particle dynamics is not well understood. Herein, we report the dynamics of rigid microparticles in confined flows of strongly shear-thinning viscoelastic (STVE) fluids at very low Reynolds numbers. Our experiments with different STVE fluids reveal five different regimes: original streamline, bimodal, center migration, defocusing, and wall migration (WM), depending upon the fluid properties and flow rates. It is found that the occurrence of the different regimes depends on the STVE parameter (ψ) and average strain rate (γ̇¯). We find that the dynamics of particles in the different regimes is underpinned by the synergy between viscoelastic lift force (FVE) and shear-thinning lift force (FST). Numerical simulation results of strain rate and viscosity profiles at different ψ and γ̇¯ enable estimation of the forces and explaining the dynamics observed. We expect that our study will find relevance in applications involving positioning and manipulation of particles in confined flows of STVE fluids.
Comparison of the multi-layer multi-configuration time-dependent Hartree (ML-MCTDH) method and the density matrix renormalization group (DMRG) for ground state properties of linear rotor chains
Authors: Mainali Samrit , Gatti Fabien , Iouchtchenko Dmitri , Roy Pierre-Nicholas , Meyer Hans-Dieter
Published: May 2021

We demonstrate the applicability of the Multi-Layer Multi-Configuration Time-Dependent Hartree (ML-MCTDH) method to the problem of computing ground states of one-dimensional chains of linear rotors with dipolar interactions. Specifically, we successfully obtain energies, entanglement entropies, and orientational correlations that are in agreement with the Density Matrix Renormalization Group (DMRG), which has been previously used for this system. We find that the entropies calculated by ML-MCTDH for larger system sizes contain nonmonotonicity, as expected in the vicinity of a second-order quantum phase transition between ordered and disordered rotor states. We observe that this effect remains when all couplings besides nearest-neighbor are omitted from the Hamiltonian, which suggests that it is not sensitive to the rate of decay of the interactions. In contrast to DMRG, which is tailored to the one-dimensional case, ML-MCTDH (as implemented in the Heidelberg MCTDH package) requires more computational time and memory, although the requirements are still within reach of commodity hardware. The numerical convergence and computational demand of two practical implementations of ML-MCTDH and DMRG are presented in detail for various combinations of system parameters.
Cylinders and jets in crossflow: Wake formations as a result of varying geometric proximities
Authors: Kristo Paul J. , Kimber Mark L.
Published: May 2021

The combined flow physics of several canonical flow configurations is experimentally studied. Here, we analyze an array of jets issuing into a crossflow, then immediately navigating past an array of cylinders. This is achieved with a 2 × 3 triangular pattern of jets and symmetric cylinders at three jets to crossflow velocity ratios, enabling near-complete optical access of each jet, with velocities measured by time-resolved particle image velocimetry. Jet trajectories reveal that each configuration adheres to a power-law trend and that greater penetration is achieved by the downstream and confined jets compared to the more conventional upstream one. Recirculation regions of the upstream and downstream jets are nearly independent, with the confined jet encompassing regions of overlap with both. Turbulent statistics reveal the influence of geometric placement and velocity ratio on the time-averaged velocity, anisotropy, and Reynolds stresses incurred by each jet. Galilean decomposition utilizes a supplemental crossflow-only velocity field to delineate the influence of each jet's low- and high-pressure regions on the otherwise uniform stream. Proper orthogonal decomposition suggests that increased jet penetration decreases the number of modes required for truncation in the investigated spanwise plane. Vortex identification algorithms are applied to the reconstructed flow fields, reaffirming that with increasing velocity ratio, the jets generate vortices of their own in similar statistical formations as the cylinders. This investigation provides a foundation to aid future modeling efforts toward characterizing flow physics of importance in designing and passively controlling transverse jets with varying blockage proximities in a crossflow.
Comments on the validity of the non-stationary generalized Langevin equation as a coarse-grained evolution equation for microscopic stochastic dynamics
Authors: Glatzel Fabian , Schilling Tanja
Published: May 2021

We recently showed that the dynamics of coarse-grained observables in systems out of thermal equilibrium are governed by the non-stationary generalized Langevin equation [H. Meyer, T. Voigtmann, and T. Schilling, J. Chem. Phys. 147, 214110 (2017); 150, 174118 (2019)]. The derivation we presented in these two articles was based on the assumption that the dynamics of the microscopic degrees of freedom were deterministic. Here, we extend the discussion to stochastic microscopic dynamics. The fact that the same form of the non-stationary generalized Langevin equation as derived for the deterministic case also holds for stochastic processes implies that methods designed to estimate the memory kernel, drift term, and fluctuating force term of this equation, as well as methods designed to propagate it numerically, can be applied to data obtained in molecular dynamics simulations that employ a stochastic thermostat or barostat.
Linear stability of a surfactant-laden viscoelastic liquid flowing down a slippery inclined plane
Authors: Pal Subham , Samanta Arghya
Published: May 2021

A study of linear stability analysis of a surfactant-laden viscoelastic liquid flowing down a slippery inclined plane is carried out under the framework of Orr–Sommerfeld type eigenvalue problem. It is assumed that the viscoelastic liquid satisfies the rheological property of Walters' liquid B″. The Orr–Sommerfeld type eigenvalue problem is solved analytically and numerically based on the long-wave analysis and Chebyshev spectral collocation method, respectively. The long-wave analysis predicts the existence of two temporal modes, the so-called surface mode and surfactant mode, where the first order temporal growth rate for the surfactant mode is zero. However, the first order temporal growth rate for the surface mode is non-zero, which leads to the critical Reynolds number for the surface mode. Further, it is found that the critical Reynolds number for the surface mode reduces with the increasing value of viscoelastic coefficient and ensures the destabilizing effect of viscoelastic coefficient on the primary instability induced by the surface mode in the long-wave regime. However, the numerical result demonstrates that the viscoelastic coefficient has a non-trivial stabilizing effect on the surface mode when the Reynolds number is far away from the onset of instability. Further, if the Reynolds number is high and the inclination angle is sufficiently low, there exists another mode, namely the shear mode. The unstable region induced by the shear mode magnifies significantly even for the weak effect of viscoelastic coefficient and makes the transition faster from stable to unstable flow configuration for the viscoelastic liquid. Moreover, the slip length exhibits a dual role in the surface mode as reported for the Newtonian liquid. But it exhibits only a stabilizing effect on the shear mode. In addition, it is found that the Marangoni number also exhibits a dual nature on the primary instability induced by the surface mode in contrast to the result of the Newtonian liquid.
Planar topological Hall effect in a hexagonal ferromagnetic Fe5Sn3 single crystal
Authors: Li Hang , Ding Bei , Chen Jie , Li Zefang , Xi Xuekui , Wu Guangheng , Wang Wenhong
Published: May 2021

The planar topological Hall effect (PTHE), appearing when the magnetic field tended to be along the current, is believed to result from the real-space Berry curvature of the spin spiral structure and has been experimentally observed in skyrmion-hosting materials. In this paper, we report an experimental observation of the PTHE in a hexagonal ferromagnetic Fe5Sn3 single crystal. With a current along the c axis of Fe5Sn3, the transverse resistivity curves exhibited obvious peaks near the saturation field as the magnetic field rotated to the current and appeared more obvious with increasing temperature, which was related to the noncoplanar spin structure in Fe5Sn3. This spin structure induced nonzero scalar spin chirality, which acted as fictitious magnetic fields to conduction electrons and contributed the additional transverse signal. These findings deepen the understanding of the interaction between conduction electrons and complex magnetic structures and are instructive for the design of next-generation spintronic devices.
Self-propelled slender objects can measure flow signals net of self-motion
Authors: Cavaiola M. , Mazzino A.
Published: May 2021

The perception of hydrodynamic signals by self-propelled objects is a problem of paramount importance ranging from the field of bio-medical engineering to bio-inspired intelligent navigation. By means of a state-of-the-art fully resolved immersed boundary method, we propose different models for fully coupled self-propelled objects (swimmers, in short), behaving either as “pusher” or as “puller.” The proposed models have been tested against known analytical results in the limit of Stokes flow, finding excellent agreement. Once tested, our more realistic model has been exploited in a chaotic flow field up to a flow Reynolds number of 10, a swimming number ranging between zero (i.e., the swimmer is freely moving under the action of the underlying flow in the absence of propulsion) and one (i.e., the swimmer has a relative velocity with respect to the underlying flow velocity of the same order of magnitude as the underlying flow), and different swimmer inertia measured in terms of a suitable definition of the swimmer Stokes number. Our results show the following: (i) pusher and puller reach different swimming velocities for the same, given, propulsive force: while for pusher swimmers, an effective slender body theory captures the relationship between swimming velocity and propulsive force, this is not for puller swimmers. (ii) While swimming, pusher and puller swimmers possess a different distribution of the vorticity within the wake. (iii) For a wide range of flow/swimmer Reynolds numbers, both pusher and puller swimmers are able to sense hydrodynamic signals with good accuracy.
Excellent optoelectronic applications and electrical transport behavior of the n-WO3 nanostructures/p-diamond heterojunction: a new perspective
Authors: Yao Yu , Sang Dandan , Duan Susu , Wang Qinglin , Liu Cailong
Published: May 2021

Nanostructured n-type metal oxides/p-type boron-doped diamond heterojunctions have demonstrated a typical rectification feature and/or negative differential resistance (NDR) potentially applied in wide fields. Recently, the fabrication and electronic transport behavior of n-WO3 nanorods/p-diamond heterojunction at high temperatures were studied by Wang et al (2017 Appl. Phys. Lett.
110 052106), which opened the door for optoelectronic applications that can operate at high-temperatures, high-power, and in various harsh environments. In this perspective, an overview was presented on the future directions, challenges and opportunities for the optoelectronic applications based on the n-WO3 nanostructures/p-diamond heterojunction. We focus, in particular, on the prospects for its high temperature NDR, UV photodetector, field emission emitters, photocatalyst and optical information storage for a wide range of new optoelectronic applications.
Immobilization of La on THH-CO2H@Fe3O4 nanocomposite for the synthesis of one‐pot multicomponent reactions
Authors: Tamoradi Taiebeh , Kal-Koshvandi AfsanehTaheri , Karmakar Bikash , Maleki Ali
Published: May 2021

The current research represents a facile and competent methodology in the development of a novel magnetic nanocatalyst. This composite was synthesized by immobilizing La on Fe3O4 nanoparticles pre-functionalized with tetrahydroharman-3-carboxylic acid ligand. The prepared nanomaterial was analyzed with FT-IR, SEM, EDX, XRD, and TGA techniques. The material was catalytically investigated towards the synthesis of 5-substituted 1H-tetrazoles,1-substituted 1H-tetrazoles and tetrazolopyrimidine derivatives following different multicomponent pathways. The reactions were highly efficient affording high yields. The catalyst was retrieved magnetically and recyled in six consecutive runs without much reduction in activity.
Physicists welcome Brexit deal
Authors: Allen Michael
Published: May 2021

While there is relief that the UK has reached a deal with the European Union, the true impact of the agreement will be difficult to unravel given the ongoing pandemic, as Michael Allen reports
SKA Observatory comes into force
Authors: Makoni Munyaradzi
Published: May 2021

The SKA Observatory formally came into effect last month following a 30-day notice period after the SKA convention was ratified by the UK government on 16 December.
No gender bias in peer review, claims study
Authors: Allen Michael
Published: May 2021

Peer review does not penalize manuscripts by women and is unlikely to be the cause of gender differences in academic publishing. That is according to an analysis of 1.5 million authors.
Joe Biden picks Eric Lander as science adviser
Authors: Gwynne Peter
Published: May 2021

US president Joe Biden has chosen the geneticist Eric Lander as his science adviser and director of the Office of Science and Technology Policy (OSTP).
Dutch Nobel laureate Martinus Veltman dies aged 89
Authors: Banks Michael
Published: May 2021

The Dutch physicist Martinus Veltman, who won half of the 1999 Nobel Prize for Physics for his theoretical contributions to the Standard Model of particle physics, died on 4 January.
Nobel laureate Jack Steinberger: 1921–2020
Authors: Banks Michael
Published: May 2021

Jack Steinberger, the US particle physicist who shared the 1988 Nobel Prize for Physics with Melvin Schwartz and Leon Lederman, died on 12 December 2020 aged 99.
Life on Venus debate rumbles on
Authors: Dacey James
Published: May 2021

Disagreements remain over the spectral signatures of phosphine in the atmosphere of Venus and whether life could survive in its hostile environment in the first place. James Dacey reports from the December online meeting of the American Geophysical Union
Very deep thinking
Authors: Crease Robert P
Published: May 2021

Robert P Crease discovers why a nuclear-waste programme in Finland can help us to envisage the world a million years from now
Greatest of all time?
Authors: Padman Rachael
Published: May 2021

In response to David Appell’s feature “The 10 greatest predictions in physics” (pp36–40) in which he looks at the many theoretical physics predictions that have rocked our understanding of how the world works, and highlights the top 10 of all time.
Real versus virtual
Authors: Teixeira Paulo
Published: May 2021

In response to Matin Durrani’s editorial “Virtual virtues” (October 2020 p17), in which he states that conferences are never going to be the same, even when the COVID-19 pandemic is a distant memory.
Improving nuclear fuel safety
Authors: Allen Michael
Published: May 2021

A decade after the Fukushima disaster, Michael Allen investigates claims from academia and industry that the next generation of nuclear fuels could reduce the risk of similar accidents occurring ever again
Reinventing the science museum
Authors: Harris Margaret
Published: May 2021

Margaret Harris reviews Idea Colliders: the Future of Science Museums by Michael John Gorman
Islands in the stream
Authors: Chipkin Logan
Published: May 2021

In 1919 George Hale, head of Mount Wilson Observatory, called for the US National Academy of Sciences to host a debate about “island universes” – galaxies outside of our own.
Multi-tonal subwavelength metamaterial for absorption and amplification of acoustic and ultrasonic waves
Authors: Boccaccio Marco , Fierro Gian Piero Malfense , Bucciarelli Fabrizo , Meo Michele
Published: May 2021

In this work, an acousto-ultrasound metamaterial-based concept is proposed to achieve high multi-tonal sound absorption at specific design frequencies and their multiple harmonics, which generally requires large and complex systems. This structure can be deployed to improve the performance of air-coupled nonlinear acoustic/ultrasound imaging by filtering unwanted fundamental ultrasound responses while amplifying high order harmonics, since nonlinear ultrasonic experiments generally necessitate advanced signal processing tools digital and pass-band filters to highlight nonlinear features. The structure proposed is an Archimedean inspired spiral cavity metamaterial with a thickness of 1/62 wavelength to achieve high multi-tonal sound absorption performances at a design frequency and the multiple harmonics. The same geometrical configuration can also be used to filter a fundamental design excitation frequency f0 and amplify second harmonic of the desired excitation frequencies, 2f0. An analytical model was developed to optimise the sound absorption and amplification frequencies of the structure with a design frequency of 690 Hz, by matching the geometrical parameters with the resonance and antiresonance mechanisms of the system. Additionally, a parallel arrangement of two Archimedean-inspired spirals is also analytically and experimentally proposed, in order to achieve harmonic absorptions at the resonant frequency of each subsystem (i.e. f01 = 850 Hz, f02 = 950 Hz). Furthermore, acoustic impedance analyses have been analytically conducted in order to physically explain all the resonance and antiresonance mechanism occurring with the proposed structures. Experimental investigations show that the proposed 3D printed metamaterial-based structures are capable to achieve multi-tonal high absorption peaks (above 90%) at the fundamental frequency f0 and odd harmonics (3f0, 5f0, etc) and sound amplification of the even harmonics (2f0 and 4f0). The results show good correlation between the predicted model and experimental results, and thus the sub-wavelength metamaterial provides promising potential for controlling and achieving high level sound absorption at low frequencies and enhancing accuracy of nonlinear ultrasound imaging applications.
Influence of In-situ induction heated friction stir welding on tensile, microhardness, corrosion resistance and microstructural properties of martensitic steel
Authors: G Mohan Dhanesh , Gopi S
Published: May 2021

Induction Heated Friction Stir Welding (IH-FSW) was conducted using two varying parameters and two fixed parameters. The microstructure evaluation shows that the nugget zone’s grain size is smaller while comparing with the parent metal. Due to dynamic recrystallization during the induction heated friction stir welding, well-equiaxed grains were found in the nugget zone. The microhardness test reveals that the welded region have improved hardness than the parent metal; the high hardness was attained in the heat-affected zone. The 3 h and 24 h of weight-loss corrosion test methods were conducted using the coefficient of 0.5 M H2SO4, showing that the stir zone’s corrosion resistance is better than the parent material. The given parameter combinations obtain the best results, tool rotation of 1250 rpm, welding speed of 45 mm min−1, shoulder penetration of 0.50 mm and induction heat input of 441.8 °C at 50 W.
Fuglede’s conjecture holds on ℤ_{𝕡}²×ℤ_{𝕢}
Authors: Kiss Gergely , Somlai Gábor
Published: May 2021

The study of Fuglede’s conjecture on the direct product of elementary abelian groups was initiated by Iosevich et al. For the product of two elementary abelian groups the conjecture holds. For

Z

p
3

\mathbb {Z}_p^3

the problem is still open if

p
p

is prime and

p
≥
11

p\ge 11

. In connection we prove that Fuglede’s conjecture holds on

Z

p

2

×

Z

q

\mathbb {Z}_{p}^2\times \mathbb {Z}_q

by developing a method based on ideas from discrete geometry.
Completely degenerate lower-dimensional invariant tori in reversible systems
Authors: Jing Tianqi , Si Wen
Published: May 2021

In this paper, we consider the persistence of completely degenerate lower-dimensional invariant tori of the following reversible system
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where
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≥
n
+
2

m\geq n+2

,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="script upper H left-parenthesis z right-parenthesis equals left-parenthesis 0 comma v Superscript 2 p plus 1 Baseline plus y Subscript m Superscript l Baseline comma u y Subscript m minus 1 Superscript q Baseline right-parenthesis Superscript upper T">

H

(
z
)
=
(
0
,

v

2
p
+
1

+

y
m

l

,
u

y

m
−
1

q

)
T

\mathcal {H}(z)=(0,v^{2p+1}+y_m^{l},uy_{m-1}^q)^T

with

y
=
(

y
1

,
⋯
,

y

m
−
1

,

y

m

)

y=(y_1,\cdots ,y_{m-1},y_{m})

,

p
,
q
≥
0

p,q\geq 0

,

l
>
0

l>0

are integers, the involution

G
G

is

(
x
,
y
,
u
,
v
)
→
(
−
x
,
y
,
−
u
,
v
)

(x,y,u,v)\rightarrow (-x,y,-u,v)

,

Q

(
x
)

\mathcal {Q}(x)

is a

n
×
m

n\times m

matrix function,

ω
\omega

is a Diophantine frequency,

ϵ
\epsilon

is a small positive parameter and

ϵ

P

1

,

ϵ

P

2

\epsilon \mathcal {P}^1,\,\,\epsilon \mathcal {P}^2

are analytic perturbation terms. By the Kolmogorov-Arnold-Moser method, we prove that for sufficiently small

ϵ
\epsilon

the above reversible system admits lower-dimensional invariant tori with prescribed frequency

ω
\omega

if average of a part of

Q

(
x
)

\mathcal {Q}(x)

is non-singular. This should be the first persistence result of lower-dimensional invariant tori in completely degenerate reversible systems.
The Histopathologic Features of Sickle Cell Hepatopathy: A Multi-Institutional Study
Authors: Saeed Omer , Panarelli Nicole , Umrau Kavita , Lee Hwajeong , Westerhoff Maria , Cheng Jerome , Lin Jingmei
Published: May 2021

Objectives

Recent data on hepatic histopathology in patients with sickle cell disease (SCD) are lacking.

Methods

A total of 39 liver biopsies from SCD patients from 4 medical institutes were systematically evaluated.

Results

The average age of patients was 27 years; 23 were female. The majority of the patients had hemoglobin SS (33), 3 had hemoglobin SC, and 3 sickle cell trait. Elevated liver functional tests and evaluation for cirrhosis were the main indications for biopsy. At the time of biopsy, most had elevated liver transaminases or hepatomegaly. The most common histopathologic abnormalities were Kupffer cell erythrophagocytosis (76.9%), hemosiderosis (74.4%), sinusoidal dilatation (71.8%), and intrasinusoidal sickled red cells (69.3%). Portal inflammation, lobular inflammation, and bile duct injury were mild to minimal and present in a minority of cases. Advanced fibrosis was present in 28.2% of the cases.

Conclusions

The typical histopathologic features seen in patients with SCD include Kupffer cell erythrophagocytosis, hemosiderosis, sinusoidal dilatation, and intrasinusoidal sickled red cells in a pauci-inflammatory or uninflamed background. Necrosis is less common than reported in older literature. Pathologists should be aware that significant portal and lobular inflammation, interface activity, and bile duct injury are unusual and may be suggestive of other etiologies.
Feature-weighted ordinal classification for predicting drug response in multiple myeloma
Authors: Ma Ziyang , Ahn Jeongyoun
Published: May 2021

Motivation

Ordinal classification problems arise in a variety of real-world applications, in which samples need to be classified into categories with a natural ordering. An example of classifying high-dimensional ordinal data is to use gene expressions to predict the ordinal drug response, which has been increasingly studied in pharmacogenetics. Classical ordinal classification methods are typically not able to tackle high-dimensional data and standard high-dimensional classification methods discard the ordering information among the classes. Existing work of high-dimensional ordinal classification approaches usually assume a linear ordinality among the classes. We argue that manually labeled ordinal classes may not be linearly arranged in the data space, especially in high-dimensional complex problems.

Results

We propose a new approach that can project high-dimensional data into a lower discriminating subspace, where the innate ordinal structure of the classes is uncovered. The proposed method weights the features based on their rank correlations with the class labels and incorporates the weights into the framework of linear discriminant analysis. We apply the method to predict the response to two types of drugs for patients with multiple myeloma, respectively. A comparative analysis with both ordinal and nominal existing methods demonstrates that the proposed method can achieve a competitive predictive performance while honoring the intrinsic ordinal structure of the classes. We provide interpretations on the genes that are selected by the proposed approach to understand their drug-specific response mechanisms.

Availability and implementation

The data underlying this article are available in the Gene Expression Omnibus Database at https://www.ncbi.nlm.nih.gov/geo/ and can be accessed with accession number GSE9782 and GSE68871. The source code for FWOC can be accessed at https://github.com/pisuduo/Feature-Weighted-Ordinal-Classification-FWOC.

Supplementary information

Supplementary data are available at Bioinformatics online.
ptm: an R package for the study of methionine sulfoxidation and other posttranslational modifications
Authors: Aledo Juan Carlos
Published: May 2021

Methionine sulfoxidation is a posttranslational modification (PTM) playing important roles in cell signaling. Herein, we present ptm, an R package for the study of this modification. However, since many of the analyses applied to methionine modification can be extended to other modifications, the package can be useful to thoroughly analyze PTMs in general. Thus, within a single software environment, ptm can integrate information from up to 11 databases covering nine modifications. Different functions can work coordinately to form pipelines allowing the programmatic analysis of thousands of proteins. Alternatively, the user can simultaneously perform different analyses on the same protein of interest, combining the results into a single output. The flexibility of ptm makes it a suitable tool to address site- and protein-centric hypotheses related to PTMs. Accompanying the package, we maintain a web page containing extended documentation and examples of the tasks that can be performed with ptm.

Availability and implementation

ptm is implemented in R. Release versions are available via CRAN and work on all major operating systems. The development version is maintained at https://bitbucket.org/jcaledo/ptm. Extended documentation can be found at https://metositeptm.com

Supplementary information

Supplementary data are available at Bioinformatics online.
A Multicenter Evaluation of Probiotic Use for the Primary Prevention of Clostridioides difficile Infection
Authors: Heil Emily L , Harris Anthony D , Brown Clayton , Seung Hyunuk , Thom Kerri A , von Rosenvinge Erik , Sorongon Scott , Pineles Lisa , Goodman Katherine E , Leekha Surbhi
Published: May 2021

Background

Primary prevention of Clostridioides difficile infection (CDI) is a priority for hospitals. Probiotics have the potential to interfere with colonization and CDI. In this study, we evaluated the impact of a computerized clinical decision support (CCDS) tool to prescribe probiotics for primary prevention of CDI among adult hospitalized patients.

Methods

A CCDS tool was implemented into the electronic medical record at 4 hospitals to prompt prescription of a probiotic preparation at the time of antibiotic prescription in high-risk patients in May 2019. Interrupted time series using segmented regression analysis was conducted to evaluate hospital-wide CDI incidence for the year pre- and post-CCDS implementation. In addition, multivariable logistic regression was used to evaluate CDI incidence in patients who qualified for probiotics in the pre- vs post-intervention periods, adjusting for potential confounders. To adjust for potential differences in patients who received probiotics in the post-intervention period, propensity score-matched pairs were developed to evaluate CDI risk by receipt of probiotics.

Results

Quarterly CDI incidence increased over time post-intervention relative to baseline trends (slope change, 1.4; 95% confidence interval [CI], .9–1.9). The odds ratio (OR) of CDI was 1.41 in eligible patients post-intervention compared with pre-intervention (adjusted OR, 1.41; 95% CI, 1.11–1.79). Propensity score-matched analysis showed that patients who received probiotics did not have lower rates of CDI compared with those who did not receive probiotics (OR, 1.46; 95% CI, .87–2.45).

Conclusions

Use of probiotics for primary prevention of CDI among adult inpatients receiving antibiotics is not supported.
Shakespeare’s Cymbeline, Shaw’s Cymbeline Refinished, Kingship and the Possibility of Transformation
Authors: Kaul Mythili
Published: May 2021

The complicated closing scene of Shakespeare’s Cymbeline irritated George Bernard Shaw so much that he ‘perpetrated’ a ‘spurious Fifth Act’. His ending, however, is not a ‘variation’ on, but a reinforcing of, existing currents within Shakespeare’s text (the focus on kingship, the court and power), which is the subject of this paper.

Cymbeline and the other three Romances are not escapist. They are ‘critical Romances’, and Shakespeare uses the form/genre to make a statement on and to critique reality. They are political plays deeply ‘embroiled’ in their historical milieu, and the paper touches on the criticism of Tudor and Stuart absolutism and the constitutional questions about the monarchy that were being raised during the sixteenth and seventeenth centuries.

The emphasis on imperial reform which informs several treatises of the period revolves around the ‘education’ of the ruler, the reinculcation of values needed to redeem the deeply tainted court. In Cymbeline and the Romances, the promise of the future resides in the younger generation, whose education takes place in the pastoral and who are instructed in those human, social and communal values which are absent from the court and which they bring back when they return, thus effecting its transformation.
Multiscale, radially anisotropic shear wave imaging of the mantle underneath the contiguous United States through joint inversion of USArray and global data sets
Authors: Porritt Robert W , Becker Thorsten W , Boschi Lapo , Auer Ludwig
Published: May 2021

EarthScope's USArray seismic component provided unprecedented coverage of the contiguous United States and has therefore spurred significant advances in tomographic imaging and geodynamic modelling. Here, we present a new global, radially anisotropic shear wave velocity tomography model to investigate upper mantle structure and North American Plate dynamics, with a focus on the contiguous United States. The model uses a data-adaptive mesh and traveltimes of both surface waves and body waves to constrain structure in the crust and mantle in order to arrive at a more consistent representation of the subsurface compared to what is provided by existing models. The resulting model is broadly consistent with previous global models at the largest scales, but there are substantial differences under the contiguous United States where we can achieve higher resolution. On these regional scales, the new model contains short wavelength anomalies consistent with regional models derived from USArray data alone. We use the model to explore the geometry of the subducting Farallon Slab, the presence of upper mantle high velocity anomalies, low velocity zones in the central and eastern United States and evaluate models of dynamic topography in the Cordillera. Our models indicate a single, shallowly dipping, discontinuous slab associated with the Farallon Plate, but there are remaining imaging challenges. Inferring dynamic topography from the new model captures both the long-wavelength anomalies common in global models and the short-wavelength anomalies apparent in regional models. Our model thus bridges the gap between high-resolution regional models within the proper uppermost mantle context provided by global models, which is crucial for understanding many of the fundamental questions in continental dynamics.