bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature-dependent electronic structure of γ-phase CuI: first-principles insights
Authors: Xu Ze-Li , Yang Chang , Wu Yu-Ning
Published: December 2021

To deepen the understanding of CuI that emerges as a promising nextgeneration transparent display material, we investigate the temperature effect on the electronic structures of its room-temperature phase γ-CuI. Using density-functional-theory-based approaches, we investigate the bandgap renormalization, which is contributed by the electron-phonon (elph) interaction and lattice thermal expansion. Different from most semiconductors, the bandgap widens as temperature increases, although it only widens by 88.3 meV from 0 to 600 K. In addition, based on the temperature-dependent band structure and conventional Drude model, we investigate the influences of the effective masses and evaluate the hole mobilities limited by phonon scattering along different directions. The calculated mobilities agree well with existing experimental values. Our study not only provides a fundamental understanding of the temperature effect on the electronic structure of CuI, but also gives insights for further improvement of the electronic and thermoelectric devices based on CuI.
High-resolution RHEED analysis of dynamics of low-temperature superstructure transitions in Ge/Si(001) epitaxial system
Authors: Dirko Vladimir V , Lozovoy Kirill A , Kokhanenko Andrey P , Voitsekhovskii Alexander V
Published: December 2021

In this paper, we analyze superstructural transitions during epitaxial growth of two-dimensional layers and the formation of quantum dots by the Stranski–Krastanov mechanism in elastically stressed systems by the reflection high-energy electron diffraction method. Detailed dependences of the periodicity parameter N of the 2 × N reconstruction on the effective thickness of the deposited material in a wide range of growth temperatures during epitaxy of germanium on a silicon surface with a crystallographic orientation (001) are obtained. Superstructural transitions and the change in the value of the parameter N at low temperatures of epitaxy in this system have been investigated for the first time. It is shown that the length of dimer rows in such a reconstruction during the growth of pure germanium on silicon can reach a value of no less than N = 11. A relationship is found between the value of the parameter N, determined by elastic strains in the system, and the critical thickness of the transition from two-dimensional to three-dimensional growth. Based on this relationship, a physical mechanism is proposed that explains the nature of the temperature dependence of the critical thickness of the Stranski–Krastanov transition, which has been the subject of constant scientific disputes until now.
Investigating the thermal transport in gold decorated graphene by opto-thermal Raman technique
Authors: M K Ranjuna , Balakrishnan Jayakumar
Published: December 2021

We report a systematic study on the thermal transport properties of gold nanoparticles (Au NPs) decorated single-layer graphene on a SiO2/Si substrate by the opto-thermal Raman technique. Our results, with moderate Au NPs coverage (<10%), demonstrate an enhancement in the thermal conductivity of graphene by ∼55% from its pristine value and a decrement in the interface conductance by a factor of 1.5. A detailed analysis of our results shows the importance of the photo-thermal conversion efficiency of Au NPs, plasmon–phonon coupling and lattice modifications in the graphene developed after gold nanoparticles deposition in enhancing the thermal conductivity and reducing the interface thermal conductance of the system. Our study paves way for a better understanding of the thermal management in such hybrid systems, which are envisioned as excellent candidates for optoelectronics and photonics applications.
In-plane InGaAs/Ga(As)Sb nanowire based tunnel junctions grown by selective area molecular beam epitaxy
Authors: Bucamp A , Coinon C , Lepilliet S , Troadec D , Patriarche G , Diallo M H , Avramovic V , Haddadi K , Wallart X , Desplanque L
Published: December 2021

In-plane InGaAs/Ga(As)Sb heterojunction tunnel diodes are fabricated by selective area molecular beam epitaxy with two different architectures: either radial InGaAs core/Ga(As)Sb shell nanowires or axial InGaAs/GaSb heterojunctions. In the former case, we unveil the impact of strain relaxation and alloy composition fluctuations at the nanoscale on the tunneling properties of the diodes, whereas in the latter case we demonstrate that template assisted molecular beam epitaxy can be used to achieve a very precise control of tunnel diodes dimensions at the nanoscale with a scalable process. In both cases, negative differential resistances with large peak current densities are achieved.
Automatic detection of respiratory events during sleep from Polysomnography data using Layered Hidden Markov Model
Authors: Sadoughi Azadeh , Shamsollahi Mohammad Bagher , Fatemizadeh Emad
Published: December 2021

Objective. Sleep apnea is a serious respiratory disorder, which is associated with increased risk factors for cardiovascular disease. Many studies in recent years have been focused on automatic detection of sleep apnea from polysomnography (PSG) recordings, however, detection of subtle respiratory events named Respiratory Event Related Arousals (RERAs) that do not meet the criteria for apnea or hypopnea is still challenging. The objective of this study was to develop automatic detection of sleep apnea based on Hidden Markov Models (HMMs) which are probabilistic models with the ability to learn different dynamics of the real time-series such as clinical recordings. Approach. In this study, a hierarchy of HMMs named Layered HMM was presented to detect respiratory events from PSG recordings. The recordings of 210 PSGs from Massachusetts General Hospital’s database were used for this study. To develop detection algorithms, extracted feature signals from airflow, movements over the chest and abdomen, and oxygen saturation in blood (SaO2) were chosen as observations. The respiratory disturbance index (RDI) was estimated as the number of apneas, hypopneas, and RERAs per hour of sleep. Main results. The best F1 score of the event by event detection algorithm was between 0.22 ± 0.16 and 0.70 ± 0.08 for different groups of sleep apnea severity. There was a strong correlation between the estimated and the PSG-derived RDI (R
2 = 0.91, p < 0.0001). The best recall of RERA detection was achieved 0.45 ± 0.27. Significance. The results showed that the layered structure can improve the performance of the detection of respiratory events during sleep.
A mechanical true random number generator
Authors: Akashi Nozomi , Nakajima Kohei , Shibayama Mitsuru , Kuniyoshi Yasuo
Published: December 2021

Random number generation has become an indispensable part of information processing: it is essential for many numerical algorithms, security applications, and in securing fairness in everyday life. Random number generators (RNGs) find application in many devices, ranging from dice and roulette wheels, via computer algorithms, lasers to quantum systems, which inevitably capitalize on their physical dynamics at respective spatio-temporal scales. Herein, to the best of our knowledge, we propose the first mathematically proven true RNG (TRNG) based on a mechanical system, particularly the triple linkage of Thurston and Weeks. By using certain parameters, its free motion has been proven to be an Anosov flow, from which we can show that it has an exponential mixing property and structural stability. We contend that this mechanical Anosov flow can be used as a TRNG, which requires that the random number should be unpredictable, irreproducible, robust against the inevitable noise seen in physical implementations, and the resulting distribution’s controllability (an important consideration in practice). We investigate the proposed system’s properties both theoretically and numerically based on the above four perspectives. Further, we confirm that the random bits numerically generated pass the standard statistical tests for random bits.
Pressure-driven wrinkling of soft inner-lined tubes
Authors: Foster Benjamin , Verschueren Nicolás , Knobloch Edgar , Gordillo Leonardo
Published: December 2021

A simple equation modelling an inextensible elastic lining of an inner-lined tube subject to an imposed pressure difference is derived from a consideration of the idealised elastic properties of the lining and the pressure and soft-substrate forces. Two cases are considered in detail, one with prominent wrinkling and a second one in which wrinkling is absent and only buckling remains. Bifurcation diagrams are computed via numerical continuation for both cases. Wrinkling, buckling, folding, and mixed-mode solutions are found and organised according to system-response measures including tension, in-plane compression, maximum curvature and energy. Approximate wrinkle solutions are constructed using weakly nonlinear theory, in excellent agreement with numerics. Our approach explains how the wavelength of the wrinkles is selected as a function of the parameters in compressed wrinkling systems and shows how localised folds and mixed-mode states form in secondary bifurcations from wrinkled states. Our model aims to capture the wrinkling response of arterial endothelium to blood pressure changes but applies much more broadly.
Thermodynamic optimization of nanofluid flow over a non-isothermal wedge with nonlinear radiation and activation energy
Authors: Acharya M R , Mishra P , Panda S
Published: December 2021

This paper analyses the augmentation entropy generation number for a viscous nanofluid flow over a non-isothermal wedge including the effects of non-linear radiation and activation energy. We discuss the influence of thermodynamically important parameters during the study, namely, the Bejan number, entropy generation number, and the augmentation entropy generation number. The mathematical formulation for thermal conductivity and viscosity of nanofluid for Al
2
O
3 − EG mixture has been considered. The results were numerically computed using implicit Keller-Box method and depicted graphically. The important result is the change in augmentation entropy generation number with Reynolds number. We observed that adding nanoparticles (volume fraction) tend to enhance augmentation entropy generation number for Al
2
O
3 − EG nanofluid. Further, the investigation on the thermodynamic performance of non-isothermal nanofluid flow over a wedge reveals that adding nanoparticles to the base fluid is effective only when the contribution of heat transfer irreversibility is more than fluid friction irreversibility. This work also discusses the physical interpretation of heat transfer irreversibility and pressure drop irreversibility. This dependency includes Reynolds number and volume fraction parameter. Other than these, the research looked at a variety of physical characteristics associated with the flow of fluid, heat and mass transfer.
Evaporating primordial black holes in gamma ray and neutrino telescopes
Authors: Capanema Antonio , Esmaeili AmirFarzan , Esmaili Arman
Published: December 2021

A primordial black hole in the last stages of evaporation and located in the local neighborhood can produce a detectable signal in gamma ray and neutrino telescopes. We re-evaluate the expected gamma ray and neutrino fluxes from these transient point events and discuss the consequences for existing constraints. For gamma rays we improve the current bounds by a factor of few, while for neutrinos we obtain significantly different results than the existing literature. The capability and advantages of neutrino telescopes in the search for primordial black holes is discussed thoroughly. The correlations of gamma ray and neutrino energy and time profiles will be promoted as a powerful tool in identifying the primordial black holes, in case of detection.
Alfvén cascade eigenmodes above the TAE-frequency and localization of Alfvén modes in D–3He plasmas on JET
Authors: Dreval M. , Sharapov S.E. , Kazakov Ye.O. , Ongena J. , Nocente M. , Calado R. , Coelho R. , Ferreira J. , Figueiredo A. , Fitzgerald M. , Garcia J. , Giroud C. , Hawkes N.C. , Kiptily V.G. , Nabais F. , Nave M.F.F. , Weisen H. , Craciunescu T. , Salewski M. , Štancar Ž. , JET Contributors
Published: December 2021

Various types of Alfvén eigenmodes (AEs) have been destabilized by fast ions over a broad frequency range from ∼80 kHz to ∼700 kHz in a series of JET experiments in mixed D–3He plasmas heated with the three-ion ICRF scenario (2020 Nocente et al Nucl. Fusion
60 124006). In this paper, we identify the radial localization of AEs using an X-mode reflectometer, a multiline interferometer and soft x-ray diagnostics. The analysis is focused on the most representative example of these measurements in JET pulse #95691, where two different types of Alfvén cascade (AC) eigenmodes were observed. These modes originate from the presence of a local minimum of the safety factor q
min. In addition to ACs with frequencies below the frequency of toroidal Alfvén eigenmodes (TAEs), ACs with frequencies above the TAE frequency were destabilized by energetic ions. Both low- (f ≈ 80–180 kHz) and high-frequency (f ≈ 330–450 kHz) ACs were localized in the central regions of the plasma. The characteristics of the high-frequency ACs are investigated in detail numerically using HELENA, CSCAS and MISHKA codes. The resonant conditions for the mode excitation are found to be determined by passing ions of rather high energy of several hundred keV and similar to those established in JT-60U with negative-ion-based NBI (2005 Takechi et al Phys. Plasmas
12 082509). The computed radial mode structure is found to be consistent with the experimental measurements. In contrast to low-frequency ACs observed most often, the frequency of the high-frequency ACs decreases with time as the value of q
min decreases. This feature is in a qualitative agreement with the analytical model of the high-frequency ACs in Breizman et al (2003 Phys. Plasmas
10 3649). The high-frequency AC could be highly relevant for future ITER and fusion reactor plasmas dominated by ∼MeV energetic ions, including a significant population of passing fast ions.
Pixel chamber: a solid-state active-target for 3D imaging of charm and beauty
Authors: Mulliri A. , Arba M. , Bhattacharya P. , Casula E. , Cicalò C. , De Falco A. , Mager M. , Marras D. , Masoni A. , Musa L. , Siddhanta S. , Tuveri M. , Usai G.
Published: December 2021

The aim of the pixel chamber project is to develop the first “solid-state bubble chamber” for high precision measurement of charm and beauty. In this paper we will describe the idea for the first silicon active target conceived as an ultra-high granular stack of hundreds of very thin monolithic active pixel sensors (MAPS), which provides continuous, high-resolution 3D tracking of all of the particles produced in proton-silicon interactions occurring inside the detector volume, including open charm and beauty. We will also discuss the high-precision tracking and vertexing performances, showing that the vertex resolution can be up to one order of magnitude better than state-of-the-art detectors like the LHCb one.
Segmentation of EM showers for neutrino experiments with deep graph neural networks
Authors: Belavin V. , Trofimova E. , Ustyuzhanin A.
Published: December 2021

We introduce a first-ever algorithm for the reconstruction
of multiple showers from the data collected with electromagnetic
(EM) sampling calorimeters. Such detectors are widely used in High
Energy Physics to measure the energy and kinematics of in-going
particles. In this work, we consider the case when many electrons
pass through an Emulsion Cloud Chamber (ECC) brick, initiating
electron-induced electromagnetic showers, which can be the case with
long exposure times or large input particle flux. For example, SHiP
experiment is planning to use emulsion detectors for dark matter
search and neutrino physics investigation. The expected full flux of
SHiP experiment is about 1020 particles over five years. To
reduce the cost of the experiment associated with the replacement of
the ECC brick and off-line data taking (emulsion scanning), it is
decided to increase exposure time. Thus, we expect to observe a lot
of overlapping showers, which turn EM showers reconstruction into a
challenging point cloud segmentation problem. Our reconstruction
pipeline consists of a Graph Neural Network that predicts an
adjacency matrix and a clustering algorithm. We propose a new layer
type (EmulsionConv) that takes into account geometrical properties
of shower development in ECC brick. For the clustering of
overlapping showers, we use a modified hierarchical density-based
clustering algorithm. Our method does not use any prior information
about the incoming particles and identifies up to 87% of
electromagnetic showers in emulsion detectors. The achieved energy
resolution over 16,577 showers is
σE/E = (0.095 ± 0.005) + (0.134 ±
0.011)/√(E). The main test bench for the algorithm for
reconstructing electromagnetic showers is going to be SND@LHC.
The stress measurement system for the JUNO Central Detector acrylic panels
Authors: Yang X. , Heng Y. , Li Z. , Ma X. , Qian X. , Huang K. , Wu Z. , Xu M. , He W. , Pei Y. , Wang Y.
Published: December 2021

The Jiangmen Underground Neutrino Observatory (JUNO) Central
Detector (CD) is a huge acrylic spherical vessel containing 20,000
tons of liquid scintillator; the sphere is composed of 263 pieces of
acrylic spherical panels bonded by the mass polymerization. The
operation life time of the JUNO CD is 20 years. To ensure the
structural safety during the JUNO CD life time, the acrylic stress
of CD is required not to be greater than 3.5 MPa. The stresses of
acrylic spherical panels are required to be measured during the
installation on-site; unfortunately there is no suitable commercial
measurement equipment that can meet JUNO's requirements. Therefore,
a measurement setup based on photo-elastic principle and
spectrometric methods was designed, developed and tested for on-site
measurements. The measurement system performs accurate calibration
of stress-optical coefficient of acrylic in JUNO, and gives reliable
results of acrylic stresses. The measurement system has been tested
in the Taixing Donchamp Acrylic Ltd mechanical workshop, and the
achieved results meet the JUNO's requirements. The measurement
principle, the system components, and the tooling design are
introduced in the paper. Moreover, the calibration of stress-optical
coefficient of the acrylic and measurements results on JUNO acrylic
spherical panels are discussed in the following.
Frequency-tunable wide-angle polarization selection with a graphene-based anisotropic epsilon-near-zero metamaterial
Authors: Wu Feng , Liu Dejun , Wu Xiaohu , Li Hongju , Xiao Shuyuan
Published: December 2021

In this paper, we achieve frequency-tunable wide-angle polarization selection based on an anisotropic epsilon-near-zero (AENZ) metamaterial mimicked by a subwavelength graphene/SiO2 multilayer. The physical mechanism of wide-angle polarization selection can be explained by the analysis of the iso-frequency curve (IFC). Under transverse electric polarization, only the incident lights which are close to normal incidence can transmit through the designed multilayer since the IFC of the AENZ metamaterial is an extremely small circle. However, under transverse magnetic polarization, all the incident lights can transmit through the designed multilayer since the IFC of the AENZ metamaterial is a flat ellipse. Therefore, polarization selection can work in a broad angular width. By changing the gate voltage applying to the graphene, the operating frequency of polarization selection can be flexibly tuned. The optimal operating angular width of high-performance polarization selection where the polarization selection ratio is larger than 102 reaches 54.9°. This frequency-tunable wide-angle polarization selector would possess potential applications in liquid crystal display, read-write magneto-optical data storage, Q-switched lasing, and chiral molecule detection.
High tunability and sensitivity of 1D topological photonic crystal heterostructure
Authors: Elshahat Sayed , Mohamed Zain Elabdeen A , Almokhtar Mohamed , Lu Cuicui
Published: December 2021

A modality to high tunability and sensing performance of a one-dimensional (1D) topological photonic crystal (PC) heterostructure is realized, based on a new mechanism through a 1D topological PC. By inserting an aqueous defect layer as a sandwich between two 1D PCs, transmittance gradually decreases with the increasing thickness of the defect layer. However, when the two layers of the topological heterostructure interface are replaced by the defect layer, the tunability and all sensing capabilities are improved, and the principle of topology is preserved. A topologically protected edge state is formed at the heterostructure interface with a highly localized electric field. For glucose sensing, high sensitivity S = 603.753 nm RIU−1 is obtained at the low detection limit of about DL = 1.22 ×

10

−
4

RIU with high-quality factor Q =

2.33
×

10
4

and a high figure of merit FOM =

8147.814

RI

U

−
1

. Besides, the transmittance can be maintained at over 99% at low and/or high glucose concentrations, due to the coupling topological edge mode between defect mode and topological edge state. An excellent platform is examined to design a topological photonic sensor. This flexible platform can be used for any type of sensor solely by replacing the interface layers with different sensor materials. Thus, our results will promote the development of 1D topological photonic devices.
Rubber aging life prediction based on interpolation and improved time-temperature superposition principle
Authors: Kunheng Li , Zhiyong Chen , Wenku Shi
Published: December 2021

With focus on quickly and accurately predicting and evaluating the aging performance degradation of rubber at room temperature, the pseudo-failure life at each different acceleration temperature is proposed to be calculated by interpolation method based on indoor high temperature accelerated aging data, and on the basis of the obtained pseudo-failure life. By introducing the time-temperature equivalence principle, a shift factor obeying to an Arrhenius law is derived, and master curves are built as well for the compression set as for the ultimate mechanical properties. The concept of the sum of squares of dispersion coefficient errors is proposed to evaluate the prediction accuracy. Meanwhile a quantitative calculation method that considers the effect of temperature on the performance degradation curve and the shift factor is innovatively proposes. The results show that the proposed optimization method based on the traditional time-temperature superposition principle can quickly process the aging life at room temperature, and the prediction results are distributed within the 3-fold dispersion line, which can well meet the engineering requirements. The reduction of the DSC value from 1.4164 to 1.0828 further demonstrates the effectiveness of the proposed method above. This method can provide some reference for other related polymer materials accelerated aging data processing and life prediction.
Quantitative analysis and time-resolved characterization of simulated tokamak exhaust gas by laser-induced breakdown spectroscopy
Authors: HE Yaxiong , XU Tao , ZHANG Yong , KE Chuan , ZHAO Yong , LIU Shu
Published: December 2021

Tokamak exhaust is an important part of the deuterium-tritium fuel cycle system in fusion reactions. In this work, we present a laser-induced breakdown spectroscopy (LIBS)-based method to monitor the gas compositions from the exhaust system in the tokamak device. Helium (He), a main impurity in the exhaust gas, was mixed with hydrogen (H2) in different ratios through a self-designed gas distribution system, and sealed into a measurement chamber as a standard specimen. A 532 nm wavelength laser pulse with an output power of 100 mJ was used for plasma excitation. The time-resolved LIBS is used to study the time evolution characteristics of the signal strength, signal-to-background ratio (SBR), signal-to-noise ratio (SNR) and relative standard deviation (RSD) of the helium and hydrogen characteristic lines. The Boltzmann two-line method was employed to estimate the plasma temperature of laser-induced plasma (LIP). The Stark-broadened profile of He I 587.56 nm was exploited to measure the electron density. From these studies, an appropriate time was determined in which the low RSD% was consistent with the high signal-to-noise ratio. The He I 587.56 nm and Hα emission lines with good signal-to-noise ratio were extracted from the spectrum and used in the external standard method and internal standard method for quantitative analysis. The test results for mixed gas showed that the average relative error of prediction was less than 11.15%, demonstrating the great potential of LIBS in detecting impurities in plasma exhaust gas.
Numerical study of atmospheric-pressure argon plasma jet propagating into ambient nitrogen
Authors: JIANG Yuanyuan , WANG Yanhui , HU Yamin , ZHANG Jiao , WANG Dezhen
Published: December 2021

A 2D axial symmetry fluid model is applied to study the features of an atmospheric-pressure argon (Ar) plasma jet propagating into ambient nitrogen (N2) driven by a pulsed voltage, emphasizing the influence of gas velocity on the dynamic characteristics of the jet. The results show that the Ar jet exhibits a cylindrical-shaped channel and the jet channel gradually shrinks with the increase in propagation length. The jet propagation velocity varies with time. Inside the dielectric tube, the plasma jet accelerates propagation and reaches its maximum value near the nozzle. Exiting the tube, its velocity quickly decreases and when approaching the metal plane, the decrease in jet velocity slows down. The increase in gas speed results in the variation of jet spatial distribution. The electron density presents a solid structure at lower gas flow speeds, whereas an annular structure can be observed under the higher gas flow velocity in the ionization head. The jet length increases with the flow velocity. However, when the flow velocity exceeds a critical value, the increase in the rate of the plasma jet length slows down. In addition, the gas velocity effect on the generation and transport of the reactive particles is also studied and discussed.
UK government plans to ‘unleash’ nation’s space sector
Authors: Banks Michael
Published: December 2021

The UK government has released a National Space Strategy to provide a long-term vision for the country’s space sector.
Dawn of a new HERA for South African radio astronomy
Authors: Makoni Munyaradzi
Published: December 2021

A $25m radio telescope in South Africa that is dedicated to observing the early universe is expected to be complete early next year.
Defining equality
Authors: Lawrence Anya
Published: December 2021

In response to Jim Grozier’s letter “Avoiding ‘alliarship’” in which he calls for consistent terminology on the subject of equality, diversity and inclusion (EDI), referencing Anya Lawrence’s Forum article “Beware of the ‘alliars’”.
Weighty issue
Authors: Calverd Alan , Watson Tim
Published: December 2021

A response to Nick England’s letter “Going in circles” in which he discusses the change from teaching centrifugal force to teaching centripetal force, and the definition of weight being changed from the reaction force felt from the floor to the pull of gravity on an object.
Higher dimensions
Authors: Huber Michael , Hiscott Laura
Published: December 2021

In response to Laura Hiscott’s article “Magic smartphone trees” in which she reviews the book Brave Green World: How Science Can Save Our Planet by Chris Forman and Claire Asher.
Life beyond the Nobel
Authors: Durrani Matin , Hiscott Laura , Harris Margaret , Banks Michael
Published: December 2021

Many physicists who win a Nobel prize find the freedom it brings lets them carve out new research paths. But often the shift in focus began long before their prize was conferred, as Physics World editors discover.
International network proposed to tackle satellite constellation issues
Authors: Gwynne Peter
Published: December 2021

Astronomers and satellite companies have joined forces to propose an international network to monitor the quality of astronomical observations, which are increasingly threatened by new communications satellites.
Early stages of COVID-19 pandemic penalized women
Authors: Allen Michael
Published: December 2021

Female academics submitted fewer papers than their male peers during the first wave of the COVID-19 pandemic, prompting concerns about deepening gender inequalities in academia.
COP26 agreement fails to deliver
Authors: Banks Michael , Dacey James
Published: December 2021

The leaders of almost 200 countries agreed a new climate accord at the 26th United Nations Climate Change Conference of the Parties (COP26), though there were concerns that the pact lacked ambition.
NASA’s Lucy mission launches to Jupiter’s Trojan asteroids
Authors: Banks Michael
Published: December 2021

NASA has launched a $1bn mission to study Jupiter’s Trojan asteroids – two large clusters of rocks that are believed to be remnants of primordial material that formed the solar system’s outer planets.
Tritium troubles
Authors: Evans John
Published: December 2021

A response to the news article “UK announces five potential sites for prototype energy plant”, which details the locations shortlisted to host the UK’s prototype fusion energy plant.
The quantum battleground
Authors: Cheng Yangyang , Watson Tim
Published: December 2021

Yangyang Cheng examines a historical precedent for the emerging technological rivalry between the US and China.
Quantum for all – building a firm foundation
Authors: Commissariat Tushna , Stirling Julian
Published: December 2021

Oxford Quantum Circuits chief executive llana Wisby talks to Tushna Commissariat about UK investments and innovation in quantum technology, and the potentially world-changing impact that it could have.
Quantum physics for investors
Authors: Johnston Hamish , Valenzuela Sergio O
Published: December 2021

Hamish Johnston reviews Quantum Computing: How It Works and Why It Could Change the World by Amit Katwala, WIRED.
Dealing with deniers
Authors: Brazil Rachel
Published: December 2021

Rachel Brazil reviews How to Talk to a Science Denier: Conversations with Flat Earthers, Climate Deniers, and Others Who Defy Reason by Lee McIntyre.
Ask me anything: Farai Mazhandu
Authors: Hiscott Laura
Published: December 2021

Farai Mazhandu is chief executive and co-founder of Bayete Quantum Technologies, which seeks to use quantum technology to solve problems in areas including agriculture and healthcare for people living in Africa.
Evolutionary vs imitation learning for neuromorphic control at the edge*
Authors: Schuman Catherine , Patton Robert , Kulkarni Shruti , Parsa Maryam , Stahl Christopher , Haas N Quentin , Mitchell J Parker , Snyder Shay , Nagle Amelie , Shanafield Alexandra , Potok Thomas
Published: December 2021

Neuromorphic computing offers the opportunity to implement extremely low power artificial intelligence at the edge. Control applications, such as autonomous vehicles and robotics, are also of great interest for neuromorphic systems at the edge. It is not clear, however, what the best neuromorphic training approaches are for control applications at the edge. In this work, we implement and compare the performance of evolutionary optimization and imitation learning approaches on an autonomous race car control task using an edge neuromorphic implementation. We show that the evolutionary approaches tend to achieve better performing smaller network sizes that are well-suited to edge deployment, but they also take significantly longer to train. We also describe a workflow to allow for future algorithmic comparisons for neuromorphic hardware on control applications at the edge.
Reifenberg flatness for almost minimizers of the perimeter under minimal assumptions
Authors: Goldman Michaël , Novaga Matteo , Ruffini Berardo
Published: December 2021

The aim of this note is to prove that almost minimizers of the perimeter are Reifenberg flat, for a very weak notion of minimality. The main observation is that smallness of the excess at some scale implies smallness of the excess at all smaller scales.
On cubic fourfolds with an inductive structure
Authors: Koike Kenji
Published: December 2021

We study the number of planes in four dimensional projective hypersurfaces which have so-called inductive structure. We also determine transcendental lattices of cubic fourfolds of this type.
The 𝐿_{𝑝} Brunn-Minkowski inequalities for dual quermassintegrals
Authors: Xi Dongmeng , Zhang Zhenkun
Published: December 2021

From a convex geometry viewpoint, we proved the

L
p

L_p

Brunn-Minkowski inequalities for

q
q

-th dual quermassintegrals, when

p
≥
q

p\geq q

.

Based on these inequalities, we obtain relevant uniqueness results of the

(
p
,
q
)

(p,q)

-th dual curvature measures (up to a dilation when

p
=
q

p=q

). As a special case

q
=
0

q=0

, we obtain the uniqueness of

L
p

L_p

integral curvature measure. Part of these uniqueness results were obtained before from different viewpoints.
On the regularity theory for mixed local and nonlocal quasilinear elliptic equations
Authors: Garain Prashanta , Kinnunen Juha
Published: December 2021

We consider a combination of local and nonlocal

p
p

-Laplace equations and discuss several regularity properties of weak solutions. More precisely, we establish local boundedness of weak subsolutions, local Hölder continuity of weak solutions, Harnack inequality for weak solutions and weak Harnack inequality for weak supersolutions. We also discuss lower semicontinuity of weak supersolutions as well as upper semicontinuity of weak subsolutions. Our approach is purely analytic and it is based on the De Giorgi-Nash-Moser theory, the expansion of positivity and estimates involving a tail term. The main results apply to sign changing solutions and capture both local and nonlocal features of the equation.
External Validation of Clinical Prediction Models in Unilateral Primary Aldosteronism
Authors: Sam Davis , Kline Gregory A , So Benny , Hundemer Gregory L , Pasieka Janice L , Harvey Adrian , Chin Alex , Przybojewski Stefan J , Caughlin Cori E , Leung Alexander A
Published: December 2021

BACKGROUND

Targeted treatment of primary aldosteronism (PA) is informed by adrenal vein sampling (AVS), which remains limited to specialized centers. Clinical prediction models have been developed to help select patients who would most likely benefit from AVS. Our aim was to assess the performance of these models for PA subtyping.

METHODS

This external validation study evaluated consecutive patients referred for PA who underwent AVS at a tertiary care referral center in Alberta, Canada during 2006–2018. In alignment with the original study designs and intended uses of the clinical prediction models, the primary outcome was the presence of lateralization on AVS. Model discrimination was evaluated using the C-statistic. Model calibration was assessed by comparing the observed vs. predicted probability of lateralization in the external validation cohort.

RESULTS

The validation cohort included 342 PA patients who underwent AVS (mean age, 52.1 years [SD, 11.5]; 201 [58.8%] male; 186 [54.4%] with lateralization). Six published models were assessed. All models demonstrated low-to-moderate discrimination in the validation set (C-statistics; range, 0.60–0.72), representing a marked decrease compared with the derivation sets (range, 0.80–0.87). Comparison of observed and predicted probabilities of unilateral PA revealed significant miscalibration. Calibration-in-the-large for every model was >0 (range, 0.35–1.67), signifying systematic underprediction of lateralizing disease. Calibration slopes were consistently <1 (range, 0.35–0.87), indicating poor performance at the extremes of risk.

CONCLUSIONS

Overall, clinical prediction models did not accurately predict AVS lateralization in this large cohort. These models cannot be reliably used to inform the decision to pursue AVS for most patients.
Screening of flavor compounds usingUcp1-luciferase reporter beige adipocytes identified 5-methylquinoxaline as a novel UCP1-inducing compound
Authors: Kawarasaki Satoko , Matsuo Kazuki , Kuwata Hidetoshi , Zhou Lanxi , Kwon Jungin , Ni Zheng , Takahashi Haruya , Nomura Wataru , Kenmotsu Hisanori , Inoue Kazuo , Kawada Teruo , Goto Tsuyoshi
Published: December 2021

Uncoupling protein 1 (UCP1) in brown or beige adipocytes is a mitochondrial protein that is expected to enhance whole-body energy expenditure. For the high-throughput screening of UCP1 transcriptional activity regulator, we established a murine inguinal white adipose tissue-derived Ucp1-luciferase reporter preadipocyte line. Using this reporter preadipocyte line, 654 flavor compounds were screened, and a novel Ucp1 expression-inducing compound, 5-methylquinoxaline, was identified. Adipocytes treated with 5-methylquinoxaline showed increased Ucp1 mRNA expression levels and enhanced oxygen consumption. 5-Methylquinoxaline induced Ucp1 expression through peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α), and 5-methylquinoxaline-induced PGC1α activation seemed to be partially regulated by its phosphorylation or deacetylation. Thus, our Ucp1-luciferase reporter preadipocyte line is a useful tool for screening of Ucp1 inductive compounds.
Generation and characterization of human Fetal membrane and Decidual cell lines for reproductive biology experiments
Authors: Radnaa Enkhtuya , Urrabaz-Garza Rheanna , Elrod Nathan D , de Castro Silva Mariana , Pyles Richard , Han Arum , Menon Ramkumar
Published: December 2021

Human fetal membrane and maternal decidua parietalis form one of the major feto-maternal interfaces during pregnancy. Studies on this feto-maternal interface is limited as several investigators have limited access to the placenta, and experience difficulties to isolate and maintain primary cells. Many cell lines that are currently available do not have the characteristics or properties of their primary cells of origin. Therefore, we created, characterized the immortalized cells from primary isolates from fetal membrane-derived amnion epithelial cells, amnion and chorion mesenchymal cells, chorion trophoblast cells and maternal decidua parietalis cells. Primary cells were isolated from a healthy full-term, not in labor placenta. Primary cells were immortalized using either a HPV16E6E7 retroviral or a SV40T lentiviral system. The immortalized cells were characterized for the morphology, cell type-specific markers, and cell signalling pathway activation. Genomic stability of these cells was tested using RNA seq, karyotyping, and short tandem repeats DNA analysis. Immortalized cells show their characteristic morphology, and express respective epithelial, mesenchymal and decidual markers similar to that of primary cells. Gene expression of immortalized and primary cells were highly correlated (R = 0.798 to R = 0.974). Short tandem repeats DNA analysis showed in the late passage number (>P30) of cell lines matched 84-100% to the early passage number (<P10) of the cell lines revealing there were no genetic drift over the passages. Karyotyping also revealed no chromosomal anomalies. Creation of these cell lines can standardize experimental approaches, eliminate subject to subject variabilities, and benefit the reproductive biological studies on pregnancies by using these cells.
Objective improvement with coronary anastomosis simulation training: meta-analysis
Authors: O’Dwyer Marliza , Fleming Cristina A. , Ahern Shane , Barrett Sean , Raftery Nicola B. , Ní Dhonnchú Tara , Doddakula Kishore
Published: December 2021

Background

Coronary artery anastomosis training and assessment are vital for patient safety and for conferring a prognostic benefit. A systematic review and meta-analysis were performed to analyse the impact of simulation on coronary anastomosis proficiency in terms of time taken and skill score.

Methods

This review was conducted in accordance with PRISMA guidelines, searching PubMed, Embase and Cochrane databases on 10 October 2020, using the terms ‘Coronary anastomosis simulation’ or ‘vascular anastomosis simulation’ and ‘anastomosis simulation’. Studies included had objective measurement of scores of before and after simulation. Meta-analysis was performed using RevMan, version 5.4 (Cochrane Library).

Results

From a pool of 1687 articles, 12 articles evaluating the use of simulation in teaching coronary anastomosis were identified, with objective scores at baseline and after simulation. The 12 papers included 274 subjects. Data on 223 subjects could be extracted for analysis in performing coronary anastomosis in a simulated environment. Eight trials evaluated improvement in time and 12 trials evaluated performance using an objective evaluation score. In comparison with no formal simulation training, simulation was associated with improved skill in a five-point scale (standardized mean difference 1.68 (95 per cent c.i. 1.23 to 2.13; P < 0.001)) and time (mean difference 205.9 s (95 per cent c.i. 133.62 to 278.18; P < 0.001)) in trials included in the meta-analysis. Furthermore, novice cardiothoracic surgeons benefited more from simulation as regards time improvement compared with senior cardiothoracic surgeons (293 versus 120 s improvement; P = 0.003). Fidelity of simulator did not have a significant effect on rates of improvement.

Conclusion

Simulation-based training in coronary anastomosis is associated with improved time efficiency and overall performance in comparison with no intervention. Further studies are necessary to determine the optimum timing of trainees progressing from simulation training to live operating.
Social work practice for COVID-19 in the acute hospital setting: Recommendations for psychosocial assessment
Authors: Ready James , Lewis Greg , Barr-Lynch Sandra , Casey Amanda , King Ashley , Wojciechowski Lisa
Published: December 2021

The global coronavirus SARS-CoV2 (COVID-19) pandemic outbreak caused immediate, far-reaching social schisms and created unprecedented challenges for hospital social work services worldwide. Existing hospital disaster plans were inadequately equipped for pandemics and organisational plans needed to quickly adapt to respond to the increased clinical demands and unique logistical considerations triggered by the virus. Literature reviews provided little in the way of precise guidance for practitioners. Hospital social workers responded not only to a new cohort of patients, but also to all patients affected by the societal repercussions of the pandemic and by governments’ attempts to mitigate the impacts of the virus. Psychosocial assessments, the bedrock of social work intervention, needed to adapt and evolve to encompass and address the exacerbation of existing social risks in new ways. This article originated from the authors’ interest in identifying practice implications for hospital social work during the COVID-19 pandemic. The authors briefly outline the distinct impact of COVID-19 on psychosocial issues such as domestic and family violence, elder abuse, child protection, financial stress and social isolation. They create a forum of international hospital social work centres to develop a consensus approach for addressing these issues in the context of a social work psychosocial assessment.
What ‘Omics can tell us about antifungal adaptation
Authors: Ribeiro Gabriela Fior , Denes Eszter , Heaney Helen , Childers Delma S
Published: December 2021

Invasive candidiasis, the most frequent healthcare-associated invasive fungal infection, is commonly caused by Candida albicans. However, in recent years other antifungal-resistant Candida species—namely Candida glabrata and Candidaauris—have emerged as a serious matter of concern. Much of our understanding of the mechanisms regulating antifungal resistance and tolerance relies on studies utilizing C. albicans, C. glabrataand the model yeast Saccharomyces cerevisiae. ‘Omics studies have been used to describe alterations in metabolic, genomic and transcriptomic expression profiles upon antifungal treatment of fungal cells. The physiological changes identified by these approaches could significantly affect fungal fitness in the host and survival during antifungal challenge, as well as provide further understanding of clinical resistance. Thus, this review aims to comparatively address ‘omics data for C. albicans, C. glabrata andS. cerevisiae published from 2000 to 2021 to identify what these technologies can tell us regarding cellular responses to antifungal therapy. We will also highlight possible effects on pathogen survival and identify future avenues for antifungal research.
Geometry-dependent rupture process of the 2015 Gorkha, Nepal, earthquake determined using a dip-varying inversion approach with teleseismic, high-rate GPS, static GPS and InSAR data
Authors: Xu Yueyi , Zhang Yong , Xu Lisheng
Published: December 2021

Fault geometry is widely recognized as one of the most important factors that affect the rupture process and damages of earthquakes. However, there have been few earthquake cases in which the close relation between the fault geometry and rupture process is resolved from inversions of seismic and geodetic observations. In this study, we develop an approach to simultaneously estimate the rupture process and dip-angle variation on the fault. The effectiveness of our new approach was validated through inverse numerical tests. We apply the new approach to the 2015 Mw7.8 Gorkha earthquake and obtain a dip-varying rupture model by jointly inverting the teleseismic, near-fault high-rate GPS, static co-seismic GPS and InSAR data. Our results show a ramp–flat décollement-ramp fault geometry of the earthquake. The shallow ramp may have prevented the rupture from breaking through to the surface. The variation of dip angle changing with depth leads to significantly different rupture velocities and rupture lengths at shallow and deep fault portions. Particularly, the northeastern downdip ramp behaves as a geometric barrier and rapidly slows down the rupture propagation in 35–45 s after the rupture initiation. In contrast, the rupture duration and fault length in the updip portion are relatively long since there is no significant lateral dip change. Furthermore, the approach can improve our understanding of the relationship between rupture behaviour and fault geometry for other thrust low-dip-angle (dip < 45°) earthquakes.