bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical prediction of output performance of 63NiO-Si heterojunction betavoltaic cell
Authors: Wang Yu , Zheng Renzhou , Lu Jingbin , Li Xiaoyi , Chen Ziyi , Zhang Xue , Zhang Yuehui , Liang Lei , Zeng Yugang , Qin Li , Liu Yumin
Published: August 2022

For the 63NiO-Si heterojunction betavoltaic nuclear battery, the energy deposition of the energy conversion material itself was simulated by Monte Carlo simulation, and the structure of the 63NiO-Si heterojunction was optimized based on the theoretical calculation results. When the thickness of 63NiO is 4 μm and the doping concentration of Si is 1 × 1015 cm−3, the short-circuit current density, open-circuit voltage, fill factor, and maximum output power density of the nuclear battery are 1.22 μA · cm−2, 3.17 V, 0.95, 3.67 μW · cm−2. In addition, the output performance of 63Ni/NiO-Si heterojunction betavoltaic nuclear cell was calculated in this study. Under the condition that the activity of the radioactive source and the thickness of NiO(63NiO) are the same in the two structures, the proposed structure (63NiO-Si) has greatly improved the output performance of the nuclear battery by reducing the energy lost from radioactive source self-absorption.
Enhancing the metal–insulator transition in VO2 heterostructures with graphene interlayers
Authors: Cao Hui , Yan Xi , Li Yan , Stan Liliana , Chen Wei , Guisinger Nathan P. , Zhou Hua , Fong Dillon D.
Published: August 2022

Studies were conducted on epitaxial VO2 thin films to assess to the effect of remote epitaxy on the metal–insulator transition (MIT). The epitaxial VO2 heterostructures were synthesized on both bare Al2O3 (0001) substrates and Al2O3 substrates coated with two monolayer-thick graphene. While both systems exhibit the MIT, the film grown by remote epitaxy on graphene demonstrates improved transport properties. Electrical transport measurements show that the on/off ratio is enhanced by a factor of ∼7.5 and the switching temperature window is narrower for VO2 thin films grown on graphene. By characterizing the heterostructures with a suite of structural, chemical, and spectroscopic tools, we find that the graphene interlayer inhibits oxygen vacancy diffusion from Al2O3 (0001) during the VO2 growth, resulting in improved electrical behavior at the MIT.
Tethered hard spheres: A bridge between the fluid and solid phases
Authors: MacKinnon James , Bannerman Marcus N. , Lue Leo
Published: August 2022

The thermodynamics of hard spheres tethered to a Face-Centered Cubic (FCC) lattice is investigated using event-driven molecular-dynamics. The particle–particle and the particle–tether collision rates are related to the phase space geometry and are used to study the FCC and fluid states. In tethered systems, the entropy can be determined by at least two routes: (i) through integration of the tether collision rates with the tether length rT or (ii) through integration of the particle–particle collision rates with the hard-sphere diameter σ (or, equivalently, the density). If the entropy were an entirely analytic function of rT and σ, these two methods for calculating the entropy should lead to the same results; however, a non-analytic region exists as an extension of the solid–fluid phase transition of the untethered hard-sphere system, and integration paths that cross this region will lead to values for the entropy that depend on the particular path chosen. The difference between the calculated entropies appears to be related to the communal entropy, and the location of the non-analytic region appears to be related to conditions where the regions of phase space associated with the FCC configuration become separated from those associated with the disordered fluid. The non-analytic region is finite in extent, vanishing below rT/a ≈ 0.55, where a is the lattice spacing, and there are many continuous paths that connect the fluid and solid phases that can be used to determine the crystal free energy with respect to the fluid.
Fueling limits in a cylindrical viscosity-limited reactor
Authors: Rubin T. , Kolmes E. J. , Ochs I. E. , Mlodik M. E. , Fisch N. J.
Published: August 2022

Recently, a method to achieve a “natural hot-ion mode” was suggested by utilizing ion viscous heating in a rotating plasma with a fixed boundary. We explore the steady-state solution to the Braginskii equations and find the parameter regime in which a significant temperature difference between ions and electrons can be sustained in a driven steady state. The threshold for this effect occurs at ρi≳0.1R. An analytic, leading order low flow solution is obtained, and a numerical, moderate Mach number M≲2 is investigated. The limitation is found to be at moderate Mach numbers.
Achieving higher dynamic discharge energy and power density in PLZST antiferroelectrics with lower quasi-static recoverable energy density via tuning the phase transition properties
Authors: Xu Ran , Wang Mengjiao , Zhu Qingshan , Xu Zhuo , Feng Yujun , Wei Xiaoyong
Published: August 2022

The energy density of dielectrics could be evaluated both via low-frequency P–E loop (quasi-static recoverable energy density, Wre) and fast discharge current (dynamic discharge energy density, Wdis). The value of Wdis represents the useful energy, which can be converted to electrical energy while most work about high-energy-density dielectrics is focused on enhancing Wre. In this work, we investigated the relationship between Wdis and Wre in (Pb1 − 3x/2Lax)[(Zr0.45Sn0.55)0.99Ti0.01]O3 antiferroelectrics. Tuning the phase transition properties could improve the fast discharge capability by reducing the difference between Wdis and Wre and accelerating the energy release rate. At 300 kV/cm, the composition with x = 0 has the highest Wre of 6.7 J/cm3 but a lower Wdis of only 4 J/cm3 and longer discharge time duration, indicating a “high-energy-density” (highest Wre) quasi-static performance but “low-energy-density” (lower Wdis) and slow discharge performance during fast discharge. A highest Wdis of 5.9 J/cm3 and power density were achieved in composition with x = 0.2 though with lower Wre. The various fast energy release performance was explained by their different domain mobility and phase switching behavior. Thus, purely pursing high Wre is with limitation and suppressing the difference between Wdis and Wre is with great significance. This work will give an approach for the development of energy storage dielectrics by connecting their fast discharge performance with polarization mechanism.
Discharge characteristics and mode transition of a ring-cusp magnetically confined plasma bridge neutralizer
Authors: Ren Linyuan , Wang Yanan , Ding Weidong , Sun Anbang , Karadag Burak , Deng Zichen , Geng Jinyue
Published: August 2022

The discharge mode characteristics of cathodes may strongly influence the discharge stability and performance of electrostatic thrusters. In this article, discharge characteristics and mode transition phenomenon of the ring-cusp magnetically confined plasma bridge neutralizer (RCM-PBN) were experimentally studied using argon as the working gas. The dependences of anode current and oscillation amplitude on anode voltage, argon flow rate, heater power, and cathode-to-anode distance were investigated. Plasma properties were measured and plasma plume images were taken under different discharge modes. Two distinct discharge modes were observed during the experiments: high oscillation mode and low oscillation mode. In the high oscillation mode, the plasma plume appears dim, the anode current is low, and the oscillation level is more than 2%. While in the low oscillation mode, a spot-like structure close to the orifice is observed. The plume becomes brighter, the anode current increases, and the oscillation level decreases below 2%. The RCM-PBN was found to transition into the low oscillation mode by increasing anode voltage, flow rate, heater power and by decreasing the cathode-to-anode distance.
Quantum edge plasmon excitations and electron spill-out effect
Authors: Akbari-Moghanjoughi M.
Published: August 2022

In this paper, by using the effective Schrödinger–Poisson model, we investigate quantum edge plasmon excitations and electron spill-out effect in an arbitrary degenerate electron gas in the presence of perpendicular electron drift momentum. It is found that the single-electron Schrödinger equation solution produces a nonoscillatory electron number density distribution on the interface showing characteristic surface-dipole and electron spill-out effects. However, the Schrödinger–Poisson model produces large amplitude dual-tone density distribution due to both wave-like and particle-like plasmon dispersion other than surface-dipole and electron spill-out effects. The variations in the density structure are investigated in terms of different parameters such as the chemical potential, temperature, quantum electron tunneling parameter, and perpendicular electron de Broglie's wavenumber. Furthermore, we extend our study to the case of collective electron tunneling and reveal that the interface potential energy significantly differs from the case of single-electron quantum tunneling and strongly depends on the electron gas parameters. The current study reveals interesting features of the transverse plasmon excitations and electron spill-out in a current carrying narrow metal slab or metal–dielectric quantum sandwich interfaces incorporating both single-electron and collective quantum tunneling.
Ultrahigh focal sensitivity in a relaxor ferroelectric crystal-based piezoelectric adaptive lens
Authors: Qiao Liao , Gao Xiangyu , Jin Haonan , Xin Benjian , Liu Jinfeng , Zheng Huaibin , Dong Shuxiang , Xu Zhuo , Li Fei
Published: August 2022

Traditional piezoelectric adaptive lenses (ALENS) are fabricated by piezoceramics with transparent liquids as the filling media. However, it is challenging to achieve high focal sensitivity and long-time robustness because of the low piezoelectricity of ceramics as well as the evaporation and leakage of the liquids. To overcome the above-mentioned issues, we design a piezoelectric lens based on a radial extension-arching mode by using polydimethylsiloxane films and Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIMNT) relaxor ferroelectric single crystals to replace the transparent liquids and Pb(Zr, Ti)O3 (PZT) ceramics, respectively. Due to the ultrahigh piezoelectric properties (d33 ∼ 1500 pC N−1 and d31 ∼ 730 pC N−1) of the PIMNT crystals and the optimized radial extension-arching structure, an ultrahigh focal sensitivity (8.5 cm V−1 and a fast response time (∼102 μs) is achieved, outperforming conventional ALENS based on piezoceramic actuators (∼103 μs and ∼10−1 cm V−1) and dielectric elastomer actuators (∼105 μs and ∼10−2 cm V−1). The largest output displacement of our designed ALENS is up to 53.6 μm at 4.2 kHz under 80 Vpp, and its focus is in the range of 57.44 cm to ∞. Furthermore, its performance remains unchanged after 4 × 107 vibration cycles, indicating its long-time robustness. This work sheds light on the design of advanced adaptive optical systems, where an ultrahigh focal sensitivity and a fast response are required.
Analyzing phase separation processes in binary dusty plasmas using a polarization-sensitive camera
Authors: Melzer A. , Maier D. , Schütt S.
Published: August 2022

Under the weightlessness conditions of parabolic flights, phase separation processes in a binary mixture of dust particles in a dusty plasma have been experimentally studied using a polarization-sensitive camera. The camera allows a pixel-wise derivation of the polarization state of the light scattered by the dust. With this, the light scattered from individual particles in a dust cloud consisting of dust particles with two different sizes has been analyzed. By comparison with analytical calculations of the scattered light polarizations, a technique has been developed to discriminate between the two different species, even for small size disparities. With that, the dynamics of the phase separation process of the two species is followed over the entire parabola and it is found that the larger particles preferably assemble on the outer parts of the dust cloud whereas the smaller particles accumulate on the inner parts.
High performance near-infrared MoTe2/Ge heterojunction photodetector fabricated by direct growth of Ge flake on MoTe2 film substrate
Authors: Lei Wenyu , Wen Xiaokun , Cao Guowei , Yang Li , Zhang Pengzhen , Zhuge Fuwei , Chang Haixin , Zhang Wenfeng
Published: August 2022

We demonstrated a feasible strategy to fabricate MoTe2/Ge heterojunction by direct growth of Ge flake on a MoTe2 film substrate with a two-step chemical vapor deposition method. A thin transition layer (∼4 nm) mainly composed of polycrystalline germanium at the MoTe2/Ge interface was verified during the Ge flake growth. The MoTe2/Ge heterojunction-based photodetector exhibits both the response speed with a rise/fall time of 7/4 μs and the photoresponsivity and detectivity with 4.87 A W−1 and 5.02 × 1011 Jones under zero bias in the near-infrared regime, respectively. The characteristics of device performance imply its practical applicability as building block for potential near-infrared integrated photonics.
Self-heating of cryogenic high electron-mobility transistor amplifiers and the limits of microwave noise performance
Authors: Ardizzi Anthony J. , Choi Alexander Y. , Gabritchidze Bekari , Kooi Jacob , Cleary Kieran A. , Readhead Anthony C. , Minnich Austin J.
Published: August 2022

The fundamental limits of the microwave noise performance of high electron-mobility transistors (HEMTs) are of scientific and practical interest for applications in radio astronomy and quantum computing. Self-heating at cryogenic temperatures has been reported to be a limiting mechanism for the noise, but cryogenic cooling strategies to mitigate it, for instance, using liquid cryogens, have not been evaluated. Here, we report microwave noise measurements of a packaged two-stage amplifier with GaAs metamorphic HEMTs immersed in normal and superfluid 4He baths and in vacuum from 1.6 to 80 K. We find that these liquid cryogens are unable to mitigate the thermal noise associated with self-heating. Considering this finding, we examine the implications for the lower bounds of cryogenic noise performance in HEMTs. Our analysis supports the general design principle for cryogenic HEMTs of maximizing gain at the lowest possible power.
Positron generation via ultra-intense circularly polarized laser pulses colliding in near-critical-density plasmas with different thickness
Authors: Lin Zhi-Kai , Liu Jian-Xun , Gao Ting , Lv Jin-Jian , Meng Cang-Zhen , Jin Hong-Bin , Zhao Yuan , Yu Tong-Pu , Zhao Jun
Published: August 2022

The pulses collision scheme has been demonstrated to be an effective way for the Breit–Wheeler positron generation. In this work, positron generation via two circularly polarized laser pulses colliding in near-critical-density plasmas with different thicknesses is further studied. The results show that high flux and high density positrons are generated and collected in 14 μm thick plasmas as extra backflow electrons contribute to radiation. Though the positron yield in 4 μm thick plasmas is lower than that in the thick plasmas, partial positrons are accelerated out of the collision region with a small divergence and quasi-monoenergetic energy. It is found that the Lorentz field dominates positron acceleration and collection. This investigation will further facilitate quality positron generation and application.
The dynamics of metal nanoparticles on a supporting interacting substrate
Authors: Mahmud Gazi , Zhang Hao , Douglas Jack F.
Published: August 2022

The interaction strength of the nanoparticles (NPs) with the supporting substrate can greatly influence both the rate and selectivity of catalytic reactions, but the origins of these changes in reactivity arising from the combined effects of NP structure and composition, and NP–substrate interaction is currently not well-understood. Since the dynamics of the NPs is implicated in many NP-based catalytic processes, we investigate how the supporting substrate alters the dynamics of representative Cu NPs on a model graphene substrate, and a formal extension of this model in which the interaction strength between the NPs and the substrate is varied. We particularly emphasize how the substrate interaction strength alters the local mobility and potential energy fluctuations in the NP interfacial region, given the potential relevance of such fluctuations to NP reactivity. We find the NP melting temperature Tm progressively shifts downward with an increasing NP–substrate interaction strength, and that this change in NP thermodynamic stability is mirrored by changes in local mobility and potential energy fluctuations in the interfacial region that can be described as “colored noise.” Atomic diffusivity, D, in the “free” and substrate NP interfacial regions is quantified, and observed variations are rationalized by the localization model linking D to the mean square atomic displacement on a “caging” timescale on the order of a picosecond. In summary, we find that the supporting substrate strongly modulates the stability and dynamics of supported NPs—effects that have evident practical relevance for understanding changes in NP catalytic behavior derived from the supporting substrate.
Controlled quantum dot array segmentation via highly tunable interdot tunnel coupling
Authors: Nurizzo Martin , Jadot Baptiste , Mortemousque Pierre-André , Thiney Vivien , Chanrion Emmanuel , Dartiailh Matthieu , Ludwig Arne , Wieck Andreas D. , Bäuerle Christopher , Urdampilleta Matias , Meunier Tristan
Published: August 2022

Recent demonstrations using electron spins stored in quantum dot array as qubits are promising for developing a scalable quantum computing platform. An ongoing effort is, therefore, aiming at the precise control of the quantum dot parameters in larger and larger arrays which represents a complex challenge. Partitioning of the system with the help of the inter-dot tunnel barriers can lead to a simplification for tuning and offers a protection against unwanted charge displacement. In a triple quantum dot system, we demonstrate a nanosecond control of the inter-dot tunnel rate permitting to reach the two extreme regimes, large GHz tunnel coupling, and sub-Hz isolation between adjacent dots. We use this development to isolate a subpart of the array in a metastable configuration while performing charge displacement and readout in the rest of the system. The degree of control over tunnel coupling achieved in a unit cell should motivate future protocol development for tuning, manipulation, and readout including this capability.
Observation of a reentrant structural transition in an arsenic sulfide liquid
Authors: Yuan Bing , Aitken Bruce G. , Sen Sabyasachi
Published: August 2022

A fundamental and much-debated issue in glass science is the existence and nature of liquid–liquid transitions in glass-forming liquids. Here, we report the existence of a novel reentrant structural transition in a S-rich arsenic sulfide liquid of composition As2.5S97.5. The nature of this transition and its effect on viscosity are investigated in situ using a combination of differential scanning calorimetry and simultaneous Raman spectroscopic and rheometric measurements. The results indicate that, upon heating significantly above its glass transition temperature (261 K), the constituent Sn sulfur chains in the structure of the supercooled liquid first undergo a Sn⇌S8 chain-to-ring conversion near ∼383 K, which is exothermic in nature. Further heating above 393 K alters the equilibrium to shift in the opposite direction toward an endothermic ring-to-chain conversion characteristic of the well-known λ-transition in pure sulfur liquid. This behavior is attributed to the competing effects of enthalpy of mixing and conformational entropy of ring and chain elements in the liquid. The existence of reentrant structural transitions in glass-forming liquids could provide important insights into the thermodynamics of liquid–liquid transitions and may have important consequences for harnessing novel functionalities of derived glasses.
Rapid colorimetric methods for analysis of pH, extractable aluminium and Colwell phosphorus in soils
Authors: Weligama Chandrakumara , Wasson Anton , Permalloo Gilbert , Delhaize Emmanuel
Published: August 2022

Context Analytical procedures and technologies for soil analyses can be prohibitively expensive for small laboratories and researchers in developing countries. There is a need for low cost and high-throughput methods for assaying pH, extractable aluminium and phosphorus when conducting field trials on acid soils. Aims We investigated methods to develop rapid yet inexpensive colorimetric assays for the assay of pH, extractable aluminium and Colwell phosphorus in soil extracts. Methods We developed a colorimetric method to measure soil pH enabling pH to be quantified in a high-throughput assay. Similarly, two existing methods for extractable aluminium and Colwell P were modified for high throughput assays also using microtiter plates. Key results All three methods yielded linear relationships when using absorbance to quantify the parameters with the high throughput methods. Furthermore, there was a strong correlation between pH values of the soil samples obtained with the colorimetric assay and pH values measured with a glass electrode. Conclusions We demonstrated that the rapid assays for all three methods can be implemented to characterise field sites through the mapping of distributions for extractable Al, Colwell P and pH. Implications The high-throughput methods described here will be useful for researchers who conduct field trials to map variations in soil pH, soluble Al and Colwell P. Although the focus of the current work was on acid soils, the colorimetric pH and Colwell P methods can also be applied to non-acid soils.
Optimizing the human learnability of abstract network representations
Authors: Qian William , Lynn Christopher W. , Klishin Andrei A. , Stiso Jennifer , Christianson Nicolas H. , Bassett Dani S.
Published: August 2022

Precisely how humans process relational patterns of information in knowledge, language, music, and society is not well understood. Prior work in the field of statistical learning has demonstrated that humans process such information by building internal models of the underlying network structure. However, these mental maps are often inaccurate due to limitations in human information processing. The existence of such limitations raises clear questions: Given a target network that one wishes for a human to learn, what network should one present to the human? Should one simply present the target network as-is, or should one emphasize certain parts of the network to proactively mitigate expected errors in learning? To investigate these questions, we study the optimization of network learnability in a computational model of human learning. Evaluating an array of synthetic and real-world networks, we find that learnability is enhanced by reinforcing connections within modules or clusters. In contrast, when networks contain significant core–periphery structure, we find that learnability is best optimized by reinforcing peripheral edges between low-degree nodes. Overall, our findings suggest that the accuracy of human network learning can be systematically enhanced by targeted emphasis and de-emphasis of prescribed sectors of information.
A single introduction of wild rabbits triggered the biological invasion of Australia
Authors: Alves Joel M. , Carneiro Miguel , Day Jonathan P. , Welch John J. , Duckworth Janine A. , Cox Tarnya E. , Letnic Mike , Strive Tanja , Ferrand Nuno , Jiggins Francis M.
Published: August 2022

Biological invasions are a major cause of environmental and economic disruption. While ecological factors are key determinants of their success, the role of genetics has been more challenging to demonstrate. The colonization of Australia by the European rabbit is one of the most iconic and devastating biological invasions in recorded history. Here, we show that despite numerous introductions over a 70-y period, this invasion was triggered by a single release of a few animals that spread thousands of kilometers across the continent. We found genetic support for historical accounts that these were English rabbits imported in 1859 by a settler named Thomas Austin and traced the origin of the invasive population back to his birthplace in England. We also find evidence of additional introductions that established local populations but have not spread geographically. Combining genomic and historical data we show that, contrary to the earlier introductions, which consisted mostly of domestic animals, the invasive rabbits had wild ancestry. In New Zealand and Tasmania, rabbits also became a pest several decades after being introduced. We argue that the common denominator of these invasions was the arrival of a new genotype that was better adapted to the natural environment. These findings demonstrate how the genetic composition of invasive individuals can determine the success of an introduction and provide a mechanism by which multiple introductions can be required for a biological invasion.
Wildlife susceptibility to infectious diseases at global scales
Authors: Robles-Fernández Ángel L. , Santiago-Alarcon Diego , Lira-Noriega Andrés
Published: August 2022

Disease transmission prediction across wildlife is crucial for risk assessment of emerging infectious diseases. Susceptibility of host species to pathogens is influenced by the geographic, environmental, and phylogenetic context of the specific system under study. We used machine learning to analyze how such variables influence pathogen incidence for multihost pathogen assemblages, including one of direct transmission (coronaviruses and bats) and two vector-borne systems (West Nile Virus [WNV] and birds, and malaria and birds). Here we show that this methodology is able to provide reliable global spatial susceptibility predictions for the studied host–pathogen systems, even when using a small amount of incidence information (i.e.,<20%of information in a database). We found that avian malaria was mostly affected by environmental factors and by an interaction between phylogeny and geography, and WNV susceptibility was mostly influenced by phylogeny and by the interaction between geographic and environmental distances, whereas coronavirus susceptibility was mostly affected by geography. This approach will help to direct surveillance and field efforts providing cost-effective decisions on where to invest limited resources.
Fine-scaled climate variation in equatorial Africa revealed by modern and fossil primate teeth
Authors: Green Daniel R. , Ávila Janaina N. , Cote Susanne , Dirks Wendy , Lee Daeun , Poulsen Christopher J. , Williams Ian S. , Smith Tanya M.
Published: August 2022

Variability in resource availability is hypothesized to be a significant driver of primate adaptation and evolution, but most paleoclimate proxies cannot recover environmental seasonality on the scale of an individual lifespan. Oxygen isotope compositions (δ
18
O values) sampled at high spatial resolution in the dentitions of modern African primates (
n
= 2,352 near weekly measurements from 26 teeth) track concurrent seasonal precipitation, regional climatic patterns, discrete meteorological events, and niche partitioning. We leverage these data to contextualize the first δ
18
O values of two 17 Ma
Afropithecus turkanensis
individuals from Kalodirr, Kenya, from which we infer variably bimodal wet seasons, supported by rainfall reconstructions in a global Earth system model.
Afropithecus
’ δ
18
O fluctuations are intermediate in magnitude between those measured at high resolution in baboons (
Papio
spp.) living across a gradient of aridity and modern forest-dwelling chimpanzees (
Pan troglodytes verus
). This large-bodied Miocene ape consumed seasonally variable food and water sources enriched in
18
O compared to contemporaneous terrestrial fauna (
n
= 66 fossil specimens). Reliance on fallback foods during documented dry seasons potentially contributed to novel dental features long considered adaptations to hard-object feeding. Developmentally informed microsampling recovers greater ecological complexity than conventional isotope sampling; the two Miocene apes (
n
= 248 near weekly measurements) evince as great a range of seasonal δ
18
O variation as more time-averaged bulk measurements from 101 eastern African Plio-Pleistocene hominins and 42 papionins spanning 4 million y. These results reveal unprecedented environmental histories in primate teeth and suggest a framework for evaluating climate change and primate paleoecology throughout the Cenozoic.
Real-time detection of response regulator phosphorylation dynamics in live bacteria
Authors: Butcher Ryan J. , Tabor Jeffrey J.
Published: August 2022

Bacteria utilize two-component system (TCS) signal transduction pathways to sense and adapt to changing environments. In a typical TCS, a stimulus induces a sensor histidine kinase (SHK) to phosphorylate a response regulator (RR), which then dimerizes and activates a transcriptional response. Here, we demonstrate that oligomerization-dependent depolarization of excitation light by fused mNeonGreen fluorescent protein probes enables real-time monitoring of RR dimerization dynamics in live bacteria. Using inducible promoters to independently express SHKs and RRs, we detect RR dimerization within seconds of stimulus addition in several model pathways. We go on to combine experiments with mathematical modeling to reveal that TCS phosphosignaling accelerates with SHK expression but decelerates with RR expression and SHK phosphatase activity. We further observe pulsatile activation of the SHK NarX in response to addition and depletion of the extracellular electron acceptor nitrate when the corresponding TCS is expressed from both inducible systems and the native chromosomal operon. Finally, we combine our method with polarized light microscopy to enable single-cell measurements of RR dimerization under changing stimulus conditions. Direct in vivo characterization of RR oligomerization dynamics should enable insights into the regulation of bacterial physiology.
Computational modeling of protracted HCMV replication using genome substrates and protein temporal profiles
Authors: Monti Christopher E. , Mokry Rebekah L. , Schumacher Megan L. , Dash Ranjan K. , Terhune Scott S.
Published: August 2022

Human cytomegalovirus (HCMV) is a major cause of illness in immunocompromised individuals. The HCMV lytic cycle contributes to the clinical manifestations of infection. The lytic cycle occurs over ∼96 h in diverse cell types and consists of viral DNA (vDNA) genome replication and temporally distinct expression of hundreds of viral proteins. Given its complexity, understanding this elaborate system can be facilitated by the introduction of mechanistic computational modeling of temporal relationships. Therefore, we developed a multiplicity of infection (MOI)-dependent mechanistic computational model that simulates vDNA kinetics and late lytic replication based on in-house experimental data. The predictive capabilities were established by comparison to post hoc experimental data. Computational analysis of combinatorial regulatory mechanisms suggests increasing rates of protein degradation in association with increasing vDNA levels. The model framework also allows expansion to account for additional mechanisms regulating the processes. Simulating vDNA kinetics and the late lytic cycle for a wide range of MOIs yielded several unique observations. These include the presence of saturation behavior at high MOIs, inefficient replication at low MOIs, and a precise range of MOIs in which virus is maximized within a cell type, being 0.382 IU to 0.688 IU per fibroblast. The predicted saturation kinetics at high MOIs are likely related to the physical limitations of cellular machinery, while inefficient replication at low MOIs may indicate a minimum input material required to facilitate infection. In summary, we have developed and demonstrated the utility of a data-driven and expandable computational model simulating lytic HCMV infection.
Phonon drag thermal Hall effect in metallic strontium titanate
Authors: Jiang Shan , Li Xiaokang , Fauqué Benoît , Behnia Kamran
Published: August 2022

SrTiO3, a quantum paralectric, displays a detectable phonon thermal Hall effect (THE). Here, we show that the amplitude of the THE is extremely sensitive to stoichiometry. It drastically decreases upon substitution of a tiny fraction of Sr atoms with Ca, which stabilizes the ferroelectric order. It drastically increases by an even lower density of oxygen vacancies, which turn the system to a dilute metal. The enhancement in the metallic state exceeds by far the sum of the electronic and the phononic contributions. We explain this observation as an outcome of three features: 1) Heat is mostly transported by phonons; 2) the electronic Hall angle is extremely large; and 3) there is substantial momentum exchange between electrons and phonons. Starting from Herring’s picture of phonon drag, we arrive to a quantitative account of the enhanced THE. Thus, phonon drag, hitherto detected as an amplifier of thermoelectric coefficients, can generate a purely thermal transverse response in a dilute metal with a large Hall angle. Our results reveal a hitherto-unknown consequence of momentum-conserving collisions between electrons and phonons.
An elementary alternative to ECH capacities
Authors: Hutchings Michael
Published: August 2022

The embedded contact homology (ECH) capacities are a sequence of numerical invariants of symplectic four-manifolds that give (sometimes sharp) obstructions to symplectic embeddings. These capacities are defined using embedded contact homology, and establishing their basic properties currently requires Seiberg–Witten theory. In this paper we define a sequence of symplectic capacities in four dimensions using only basic notions of holomorphic curves. The capacities satisfy the same basic properties as ECH capacities and agree with the ECH capacities for the main examples for which the latter have been computed, namely convex and concave toric domains. The capacities are also useful for obstructing symplectic embeddings into closed symplectic four-manifolds. This work is inspired by a recent preprint of McDuff and Siegel [D. McDuff, K. Siegel,arXiv[Preprint] (2021)], giving a similar elementary alternative to symplectic capacities from rational symplectic field theory (SFT).
Probabilistic forecasts of international bilateral migration flows
Authors: Welch Nathan G. , Raftery Adrian E.
Published: August 2022

We propose a method for forecasting global human migration flows. A Bayesian hierarchical model is used to make probabilistic projections of the 39,800 bilateral migration flows among the 200 most populous countries. We generate out-of-sample forecasts for all bilateral flows for the 2015 to 2020 period, using models fitted to bilateral migration flows for five 5-y periods from 1990 to 1995 through 2010 to 2015. We find that the model produces well-calibrated out-of-sample forecasts of bilateral flows, as well as total country-level inflows, outflows, and net flows. The mean absolute error decreased by 61% using our method, compared to a leading model of international migration. Out-of-sample analysis indicated that simple methods for forecasting migration flows offered accurate projections of bilateral migration flows in the near term. Our method matched or improved on the out-of-sample performance using these simple deterministic alternatives, while also accurately assessing uncertainty. We integrate the migration flow forecasting model into a fully probabilistic population projection model to generate bilateral migration flow forecasts by age and sex for all flows from 2020 to 2025 through 2040 to 2045.
Repeat sequences limit the effectiveness of lateral gene transfer and favored the evolution of meiotic sex in early eukaryotes
Authors: Colnaghi Marco , Lane Nick , Pomiankowski Andrew
Published: August 2022

The transition from prokaryotic lateral gene transfer to eukaryotic meiotic sex is poorly understood. Phylogenetic evidence suggests that it was tightly linked to eukaryogenesis, which involved an unprecedented rise in both genome size and the density of genetic repeats. Expansion of genome size raised the severity of Muller’s ratchet, while limiting the effectiveness of lateral gene transfer (LGT) at purging deleterious mutations. In principle, an increase in recombination length combined with higher rates of LGT could solve this problem. Here, we show using a computational model that this solution fails in the presence of genetic repeats prevalent in early eukaryotes. The model demonstrates that dispersed repeat sequences allow ectopic recombination, which leads to the loss of genetic information and curtails the capacity of LGT to prevent mutation accumulation. Increasing recombination length in the presence of repeat sequences exacerbates the problem. Mutational decay can only be resisted with homology along extended sequences of DNA. We conclude that the transition to homologous pairing along linear chromosomes was a key innovation in meiotic sex, which was instrumental in the expansion of eukaryotic genomes and morphological complexity.
The Antarctic ozone hole and the pattern effect on climate sensitivity
Authors: Hartmann Dennis L.
Published: August 2022

Since about 1980, the tropical Pacific has been anomalously cold, while the broader tropics have warmed. This has caused anomalous weather in midlatitudes as well as a reduction in the apparent sensitivity of the climate associated with enhanced low-cloud abundance over the cooler waters of the eastern tropical Pacific. Recent modeling work has shown that cooler temperatures over the Southern Ocean around Antarctica can lead to cooler temperatures over the eastern tropical Pacific. Here we suggest that surface wind anomalies associated with the Antarctic ozone hole can cause cooler temperatures over the Southern Ocean that extend into the tropics. We use the short-term variability of the Southern Annular Mode of zonal wind variability to show an association between surface zonal wind variations over the Southern Ocean, cooling over the Southern Ocean, and cooling in the eastern tropical Pacific. This suggests that the cooling of the eastern tropical Pacific may be associated with the onset of the Antarctic ozone hole.
Nucleotide excision repair removes thymidine analog 5-ethynyl-2′-deoxyuridine from the mammalian genome
Authors: Wang Li , Cao Xuemei , Yang Yanyan , Kose Cansu , Kawara Hiroaki , Lindsey-Boltz Laura A. , Selby Christopher P. , Sancar Aziz
Published: August 2022

Nucleotide excision repair is the principal mechanism for removing bulky DNA adducts from the mammalian genome, including those induced by environmental carcinogens such as UV radiation, and anticancer drugs such as cisplatin. Surprisingly, we found that the widely used thymidine analog EdU is a substrate for excision repair when incorporated into the DNA of replicating cells. A number of thymidine analogs were tested, and only EdU was a substrate for excision repair. EdU excision was absent in repair-deficient cells, and in vitro, DNA duplexes bearing EdU were also substrates for excision by mammalian cell-free extracts. We used the excision repair sequencing (XR-seq) method to map EdU repair in the human genome at single-nucleotide resolution and observed that EdU was excised throughout the genome and was subject to transcription-coupled repair as evidenced by higher repair rates in the transcribed strand (TS) relative to the nontranscribed strand (NTS) in transcriptionally active genes. These properties of EdU, combined with its cellular toxicity and ability to cross the blood–brain barrier, make it a potential candidate for treating cancers of the brain, a tissue that typically demonstrates limited replication in adults.
Characteristics of advanced high-strength steels obtained by the compact strip production route
Authors: Pérez-González Francisco A. , Ramírez-Ramírez Javier H. , Hernández Luis E. , Quiñones Miguel A. , Garza-Montes-de-Oca Nelson F. , Colás Rafael
Published: August 2022

Advanced high-strength steels are used in structural components of automobiles to reduce their weight, fuel consumption and green-house gas emissions. Their properties result from tailoring their chemical composition and processing conditions to obtain microstructures consisting of a variety of hard and soft components. This work presents the analyses conducted on steels produced by continuous casting into thin moulds and hot rolling directly to the final shape. The microstructure was studied by microscopical techniques; the phase transformations occurring were assessed with the aid of commercial and dedicated computer programs. The stress–strain curves were fitted to different constitutive equations. It was found that the mechanical characteristics differed due to the strategies in design and production followed by the steelmaker.
On graded 1-absorbing prime submodules
Authors: Ka’abneh Ahmad , Abu-Dawwas Rashid
Published: August 2022

Let G be a group with identity e, R be a commutative G-graded ring with unity 1 and M be a G-graded unital R-module. In this article, we introduce the concept of graded 1-absorbing prime submodule. A proper graded R-submodule N of M is said to be a graded 1-absorbing prime R-submodule of M if for all non-unit homogeneous elements x, y of R and homogeneous element m of M with xym ∈ N, either xy ∈ (N :R M) or m ∈ N. We show that the new concept is a generalization of graded prime submodules. At the same time it is a special graded 2-absorbing submodule. Several properties of a graded 1-absorbing prime submodule have been obtained. We investigate graded 1-absorbing prime submodules when the components {Mg : g ∈ G} are multiplication Re-modules.
Supplementary comparison between INTI-PTB of scattering coefficients in PC-3.5 connector (SIM.EM.RF-S17)
Authors: Monasterios G , Kuhlmann K
Published: August 2022

Main text

This document presents the final report of the supplementary comparison identified as SIM.EM.RF-S17 and carried out by the NMI (National Metrology Institute) from Argentina (INTI) and Germany (PTB).

The measurands were S-parameters up to 32 GHz in 3.5 mm coaxial connector. In addition, this comparison shows how digitalization during the measurement process and data analysis can improve a comparison outcome, this comparison being one of the first comparisons under BIPM scope in which exchanged data between participants consisted of digital uncertainty objects based on an XML structure.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Ferroelectricity in Charge-Ordering Crystals with Centrosymmetric Lattices
Authors: Yang Yali , Bellaiche Laurent , Xiang Hongjun
Published: August 2022

The switchability between the two ferroelectric (FE) states of an FE material makes FEs widely used in memories and other electronic devices. However, for conventional FEs, its FE switching only occurs between the two FE states whose spatial inversion symmetry is broken. The search for FE materials is therefore subject to certain limitations. We propose a new type of FEs whose FE states still contain spatial inversion centers. The change in polarization of this new type of FEs originates from electronic transfer between two centrosymmetric FE states under an external electric field. Taking BaBiO3 as an example, we show that charge-ordering systems can be a typical representative of this new type of FEs. Moreover, unlike traditional ferroelectrics, the change in polarization in this new type of FEs is quantum in nature with the direction dependent on the specific FE transition path. Our work therefore not only extends the concept of FEs but may also open up a new way to find multiferroics.
Improved anharmonic trap expansion through enhanced shortcuts to adiabaticity
Authors: Whitty C , Kiely A , Ruschhaupt A
Published: August 2022

Shortcuts to adiabaticity (STA) have been successfully applied both theoretically and experimentally to a wide variety of quantum control tasks. In previous work the authors have developed an analytic extension to STA, called enhanced shortcuts to adiabaticity (eSTA), that extends STA methods to systems where STA cannot be applied directly (2020 Phys. Rev. Res.
2 023360). Here we generalize this approach and construct an alternative eSTA method that takes advantage of higher order terms. We apply this eSTA method to the expansion of both a Gaussian trap and accordion lattice potential, demonstrating the improved fidelity and robustness of eSTA.
Direct measurement of the Wigner function of atoms in an optical trap
Authors: Winkelmann Falk-Richard , Weidner Carrie A , Ramola Gautam , Alt Wolfgang , Meschede Dieter , Alberti Andrea
Published: August 2022

We present a scheme to directly probe the Wigner function of the motional state of a neutral atom confined in an optical trap. The proposed scheme relies on the well-established fact that the Wigner function at a given point (x, p) in phase space is proportional to the expectation value of the parity operator relative to that point. In this work, we show that the expectation value of the parity operator can be directly measured using two auxiliary internal states of the atom: parity-even and parity-odd motional states are mapped to the two internal states of the atom through a Ramsey interferometry scheme. The Wigner function can thus be measured point-by-point in phase space with a single, direct measurement of the internal state population. Numerical simulations show that the scheme is robust in that it applies not only to deep, harmonic potentials but also to shallower, anharmonic traps.
Real-time propagator eigenstates
Authors: Oppermann F , Eicke N , Lein M
Published: August 2022

Obtaining a numerical solution of the time-dependent Schrödinger equation requires an initial state for the time evolution. If the system Hamiltonian can be split into a time-independent part and a time-dependent perturbation, the initial state is typically chosen as an eigenstate of the former. For propagation using approximate methods such as operator splitting, we show that both imaginary-time evolution and diagonalization of the time-independent Hamiltonian produce states that are not exactly stationary in absence of the perturbation. In order to avoid artifacts from these non-stationary initial states, we propose an iterative method for calculating eigenstates of the real-time propagator. We compare the performance of different initial states by simulating ionization of a model atom in a short laser pulse and we demonstrate that much lower noise levels can be achieved with the real-time propagator eigenstates.
2D/1D Z-scheme WO3/g-C3N4 photocatalytic heterojunction with enhanced photo-induced charge-carriers separation
Authors: Li Yang , Lu Yue , Jia Xiaofang , Ma Zhaoyu , Zhang Junying
Published: August 2022

Graphitic carbon nitride (g-C3N4) is a photocatalytic semiconductor with great potential for application, whereas, its photocatalytic activity is limited by the high re-combination rate of photo-generated electrons and holes. Here, we load two-dimensional (2D) WO3 nanosheets on the surface of one-dimensional (1D) g-C3N4 porous nanotubes to form a Z-scheme heterojunction. The built-in electric field at the interface of the heterojunction is conducive to promoting electrons transfer from the conduction band of WO3 to the valence band of g-C3N4 and therein combine with the holes. This inhibits electron–hole re-combination in g-C3N4 and WO3, and thus retains the high redox potential of the photo-generated charge-carriers. Therefore, the 2D/1D WO3/g-C3N4 heterojunction shows excellent photocatalytic hydrogen production and Rhodamine B degradation activities. Under simulated sunlight, photocatalytic hydrogen production rate of the WO3/g-C3N4 heterojunction reaches 7.78 mmol g−1 h−1, 2.7 times that of the single g-C3N4 porous nanotubes.