bluuebunny/crossref_metadata_2025 huggingface dataset:
The deposition properties of tetrahedral amorphous carbon coatings deposited on piston ring: Molecular dynamics simulation
Authors: Zhao Xiaowei , Lü Yanjun , Chen Ruibo , Yang Xinliang , Zhang Yongfang , Kang Jianxiong
Published: February 2024

The tetrahedral amorphous carbon (ta-C) coatings are deposited on piston rings to improve the tribological property of the piston ring-cylinder liner system of the internal combustion engines. The deposition parameters are optimized by molecular dynamics simulation to reduce the cost of coatings’ fabrication. The ta-C coatings with higher sp3 fraction, lower friction coefficient, and superior anti-wear properties are achieved by optimizing the incident energy and substrate temperature of carbon atoms. The second nearest-neighbor modified embedded-atom method potential and Tersoff potential are used to describe the interatomic interactions. The effects of the incident energy of the carbon atoms and substrate temperature on the deposition properties of the ta-C coatings are discussed. The numerical results show that the ta-C coatings with high sp3 fraction, high density, and good interface mixing are obtained, and the deposition properties of the ta-C coatings are improved.
Field-effect transistor and giant magnetoresistance effect based on optically induced antichiral edge state in graphene
Authors: Lü Xiao-Long , Liu Gang , Yang Jia-En , Xie Hang
Published: February 2024

We propose a peculiar method to induce the antichiral edge state (AES) based on off-resonant circularly polarized (ORCP) light and further study its edge-state transitions and transport properties in zigzag graphene nanoribbon. The results show that the vertical irradiation of the ORCP light on two boundaries of the system could be regarded as a modified Haldane model for inducing the AES. In particular, under the antiferromagnetic (AFM) exchange field, the system with the AES can be controlled by an electric field between spin-polarized (SP) AESs and band insulators. As a result, a SPAES/AES/SPAES junction can be formed. In two SPAES regions, the spin orientation of the SPAES can be modulated by an electric field, giving rise to the switch between the on state with enhanced conductance contributed by two edge channels and a bulk channel, and the off state. Furthermore, by modulating the AFM exchange field in two SPAES regions as parallel and antiparallel configurations, the corresponding conductance is significantly different due to the different spin directions of the AES, finally leading to giant magnetoresistance effect that can be cut off and tuned on by an electric field. In addition, the transport properties based on the AESs are moderately robust against the disorder. These findings provide a view to study the peculiar AESs and are expected to be applied in electronic devices based on the AESs.
Adsorption of triblock copolymers confined between two plates: An analytical approach
Authors: Chen Ji-Yu , Zhong Lu-Wei , Chen Er-Qiang , Yang Shuang
Published: February 2024

We present an approximate analytical approach to the adsorption problem of ABA triblock copolymers confined between two parallel plates in a θ solvent and give the expression of the propagator q(x, t) as a piece-wise function by solving the modified diffusion equation. In this way, the role of separation between the two plates, adsorption energy and block lengths on segment concentration profile, chain conformations, and interaction potential is then investigated, which agrees well with the numerical results. It is demonstrated that there are parallels between lengthening adsorbing A blocks and increasing surface affinity: strong adsorption and long adsorbing blocks favor the formation of loops and bridges, whereas more tails and free chains exist in the case of weak adsorption and short A blocks at large separations. For moderate and strong adsorptions, the bridging fraction begins to plummet at a separation larger than the end-to-end distance of non-adsorbing B block RB and becomes negligible at above 2RB owing to the entropy effect. The depth of the potential well in the interaction potential profile depends on the adsorption energy and A block length, while the location of the potential minimum corresponds to the onset of the sharp decrease in bridges.
Design of a Brownian ratchet based on repetitive aggregation and dispersion of stimuli-responsive molecules
Authors: Kim Gayoung , Kim Jun Soo
Published: February 2024

We propose a Brownian ratchet for the unidirectional transport of stimuli-responsive molecules confined in a series of asymmetric geometries. It relies on repetitive cycles of aggregation and dispersion, which cause significant changes in molecular distribution within the confining geometry and enable the Brownian motion of the molecules to be ratcheted in a specific direction. To demonstrate the feasibility of the proposed Brownian ratchet, we conducted Brownian dynamics simulations where stimuli-responsive molecules were repeatedly aggregated and dispersed in a series of truncated conical tubes by altering intermolecular interactions. These simulations demonstrated the unidirectional transport of the molecules, indicating the efficacy of the proposed Brownian ratchet. Furthermore, we found that it becomes more effective with higher concentrations of molecules. This study suggests that, through the deliberate control of molecular assembly and disassembly by stimuli-responsive intermolecular interactions, it is possible to achieve directional and controlled molecular transport in various nanoscale applications.
Development and application of hybrid AIMD/cDFT simulations for atomic-to-mesoscale chemistry
Authors: Song Duo , Bylaska Eric J. , Sushko Maria L. , Rosso Kevin M.
Published: February 2024

Many important chemical processes involve reactivity and dynamics in complex solutions. Gaining a fundamental understanding of these reaction mechanisms is a challenging goal that requires advanced computational and experimental approaches. However, important techniques such as molecular simulation have limitations in terms of scales of time, length, and system complexity. Furthermore, among the currently available solvation models, there are very few designed to describe the interaction between the molecular scale and the mesoscale. To help address this challenge, here, we establish a novel hybrid approach that couples first-principles plane-wave density functional theory with classical density functional theory (cDFT). In this approach, a region of interest described by ab initio molecular dynamics (AIMD) interacts with the surrounding medium described using cDFT to arrive at a self-consistent ground state. cDFT is a robust but efficient mesoscopic approach to accurate thermodynamics of bulk electrolyte solutions over a wide concentration range (up to 2M concentrations). Benchmarking against commonly used continuum models of solvation, such as SMD, as well as experiments, demonstrates that our hybrid AIMD–cDFT method is able to produce reasonable solvation energies for a variety of molecules and ions. With this model, we also examined the solvent effects on a prototype SN2 reaction of the nucleophilic attack of a chloride ion on methyl chloride in the solution. The resulting reaction pathway profile and the solution phase barrier agree well with experiment, showing that our AIMD/cDFT hybrid approach can provide insight into the specific role of the solvent on the reaction coordinate.
Power requirements in hovering flight of mosquitoes
Authors: Liu Yanpeng , Liu Longgui , Sun Mao
Published: February 2024

Mosquitoes exhibit distinctive flight characteristics, utilizing a combination of very small stroke amplitudes and high stroke frequencies. This study focuses on assessing the power requirements for hovering mosquitoes through numerical simulation of wing flow and aerodynamic power, coupled with analytical computation of wing inertial power. Our findings reveal that, despite the elevated stroke frequency, the primary contributor to power expenditure is the aerodynamic power, with wing inertial power being relatively negligible due to the diminutive wing mass. The specific power necessary for hovering is approximately 35 W/kg, comparable to the requirements of various other insects such as bees, flies, and moths (ranging from 20 to –60 W/kg). Moreover, the incorporation of a 100% elastic storage system yields only marginal power savings, approximately 3.5%. Consequently, while an elastic system proves somewhat beneficial, it is not indispensable for mosquito flight. Notably, altering stroke amplitude and frequency for hovering could potentially reduce power demands compared to real-case scenarios, suggesting that the conventional small stroke amplitude and high stroke frequency utilized in mosquito flight may not be the optimal choice in terms of power efficiency. The adoption of these flight characteristics in mosquitoes may be attributed to other factors, such as providing flexibility to increase amplitude in cases of substantial weight gain due to blood-feeding or conferring a selective advantage in acoustic communication through high stroke frequency.
Penetrative magneto-convection of a rotating Boussinesq flow in f-planes
Authors: Xu Fan , Cai Tao
Published: February 2024

In this study, we conducted linear instability analysis of penetrative magneto-convection in rapidly rotating Boussinesq flows within tilted f-planes, under the influence of a uniform background magnetic field. We integrated wave theory and convection theory to elucidate the penetration dynamics in rotating magneto-convection. Our findings suggest that efficient penetration in rapidly rotating flows with weakly stratified stable layers at low latitudes can be attributed to the resonance of wave transmission near the interface between unstable and stable layers. In the context of strongly stratified flows, we derived the scaling relationships of penetrative distances Δ with the stability parameter δ. Our calculation shows that, for both rotation-dominated and magnetism-dominated flows, Δ obeys a scaling of Δ∼O(δ−1/2). In rotation-dominated flows, we noted a general decrease in penetrative distance with an increased rotational effect, and a minor decrease in a penetrative distance with an increased latitude. When a background magnetic field is introduced, we observed a significant shift in the penetrative distance as the Elsasser number Λ approaches one. The penetrative distance tends to decrease when Λ≪1 and increase when Λ≫1 with the rotational effect, indicating a transition from rotation-dominated to magnetism-dominated flow. We have further investigated the impact of the background magnetic field when it is not aligned with the rotational axis. This presents a notable contrast to the case where the magnetic field is parallel to the rotational axis.
Measurement of the surface susceptibility of single-layer atomic crystal by the photonic spin Hall effect in momentum space
Authors: Zheng Dandan , Liu Shuoqing , Yang Qiang , Chen Shizhen , Wen Shuangchun , Luo Hailu
Published: February 2024

Fast and robust measurement of the surface susceptibility is still in urgent need for investigation and application of atomically thin crystals. In this work, we propose an effective method to measure the surface susceptibility of single-layer graphene by detecting the photonic spin Hall effect in momentum space. At a graphene interface, the beam separations with different spin states contain an angular component due to the existence of surface susceptibility. By implementing a postselection with real weak value in our scheme, the contribution of the spatial spin-Hall shift is excluded and the angular one is amplified for detection. It is demonstrated that treating the angular shift as a pointer allows for a reliable determination of the surface susceptibility. Our method may pave a way for the optical parameter characterization of two-dimensional atomic crystals via angular metrology.
Electrical property improvement for boron-doped diamond metal–oxide–semiconductor field-effect transistors
Authors: Liu J. W. , Teraji T. , Da B. , Koide Y.
Published: February 2024

High-performance boron-doped diamond (B-diamond) metal–oxide–semiconductor field-effect transistors (MOSFETs) are fabricated by improving fabrication process and device structures. Drain current maximum values for the B-diamond MOSFETs operating at room temperature and 300 °C are −1.2 and −10.9 mA/mm, respectively. Both exhibit on/off ratios higher than 109 and their extrinsic transconductance maximum values are 29.0 and 215.7 μS/mm, respectively. These properties surpass the values reported in previous studies.
Platypus longevity: a new record in the wild and information on captive life span
Authors: Serena Melody , Snowball Gemma , Thomas Jessica L. , Williams Geoff A. , Danger Al
Published: February 2024

We report on a male platypus (Ornithorhynchus anatinus) who was tagged in November 2000 at the age of 1 year and recaptured in September 2023, when nearly 24 years old, in a small creek system in Melbourne’s southeastern suburbs. By comparison, a female platypus recently reached the age of 30 years in captivity, though with signs of ageing that may have precluded her survival if she were living in the wild. Ten other captive individuals have lived to an age of more than 20 years in recent decades.
Single and co-inoculation of biofilm-forming rhizobacteria with macroalgae extract increase barley productivity in organic matter-limited soil
Authors: Çam Sedat , Küçük Çiğdem , Karakaş Dikilitaş Sema , Sezen Göksal , Almaca Ahmet , Cevheri Cenap
Published: February 2024

Context Limitation in soil organic matter interferes with plant growth and productivity. Chemical fertilisers can provide limiting nutrients to plants, especially in barren soil, but they have detrimental effects on living organisms; therefore, plant growth-promoting (PGP) rhizobacteria may be an alternative to synthetic fertilisers to improve plant tolerance to nutrient stress. Aims This study evaluated the effects of single and co-inoculation of two PGP rhizobacterial strains with macroalgae (Cladophora glomerata) extract on barley growth. We also tested the ability of the respective strains to produce biofilm and exopolysaccharide (EPS) at different pH values under in vitro conditions. Methods Plants were cultivated in an organic matter-limited alkaline soil under field conditions. Key results All treatments increased barley growth parameters to some extent. Growth parameters increased most in Bacillus + macroalgae extract (B + MA) and Bacillus + Azotobacter + macroalgae extract (B + A + MA) treatments. These two treatments significantly enhanced shoot length by 22.9–25.7%, dry weight of shoot + spike by 118.2–154.5%, total weight of grains by 76.5–78.1%, and number of grains per spike by 94.8–112.1% in comparison with the control. The respective two treatments also increased biofilm formation and EPS production in response to alkaline pH. Conclusions Barley productivity may be increased by using PGP strains with greater potential to produce biofilm and EPS, and inoculating them with macroalgae extract. The B + MA treatment could be applied singly or in combination with Azotobacter. Implications Single or co-inoculation of such PGP bacteria with macroalgae extract may be commercialised to enhance barley productivity in organic matter-limited soils.
COP1 controls light-dependent chromatin remodeling
Authors: Wang Wenli , Kim Junghyun , Martinez Teresa S. , Huq Enamul , Sung Sibum
Published: February 2024

Light is a crucial environmental factor that impacts various aspects of plant development. Phytochromes, as light sensors, regulate myriads of downstream genes to mediate developmental reprogramming in response to changes in environmental conditions. CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) is an E3 ligase for a number of substrates in light signaling, acting as a central repressor of photomorphogenesis. The interplay between phytochrome B (phyB) and COP1 forms an antagonistic regulatory module that triggers extensive gene expression reprogramming when exposed to light. Here, we uncover a role of COP1 in light-dependent chromatin remodeling through the regulation of VIL1 (VIN3-LIKE 1)/VERNALIZATION 5, a Polycomb protein. VIL1 directly interacts with phyB and regulates photomorphogenesis through the formation of repressive chromatin loops at downstream growth-promoting genes in response to light. Furthermore, we reveal that COP1 governs light-dependent formation of chromatin loop and limiting a repressive histone modification to fine-tune expressions of growth-promoting genes during photomorphogenesis through VIL1.
Maximally localized Wannier functions, interaction models, and fractional quantum anomalous Hall effect in twisted bilayer MoTe2
Authors: Xu Cheng , Li Jiangxu , Xu Yong , Bi Zhen , Zhang Yang
Published: February 2024

We investigate the moiré band structures and the strong correlation effects in twisted bilayer MoTe2for a wide range of twist angles, employing a combination of various techniques. Using large-scale first-principles calculations, we pinpoint realistic continuum modeling parameters, subsequently deriving the maximally localized Wannier functions for the top three moiré bands. Simplifying our model with reasonable assumptions, we obtain a minimal two-band model, encompassing Coulomb repulsion, correlated hopping, and spin exchange. Our minimal interaction models pave the way for further exploration of the rich many-body physics in twisted MoTe2. Furthermore, we explore the phase diagrams of the system through Hartree–Fock approximation and exact diagonalization (ED). Our two-band ED analysis underscores significant band-mixing effects in this system, which enlarge the optimal twist angle for fractional quantum anomalous Hall states.
Intelligent fault diagnosis of ultrasonic motors based on graph-regularized CNN-BiLSTM
Authors: Li Peng , Qin Taichun , Zhang Aibo , Li Xingqiu
Published: February 2024

The ultrasonic motor (USM) is peculiarly prone to failure due to continuous high-frequency friction-related power transfer, whose failure mechanisms are remarkably different from traditional induction motors. Intelligent fault diagnosis provides a way to alarm and avoid catastrophic losses proactively. However, previous studies using deep learning usually ignore the inherent geometric structure of the signal distribution. This paper proposes an intelligent multi-signal fault diagnosis framework for USMs to restore the linear or nonlinear manifold structure by preserving the internal structure by integrating graph regularization with deep neural networks. Firstly, the one-dimensional CNN to learn spatial correlations and BiLSTM to exploit temporal dependencies are coalesced to build the deep neural network. Then, an improved k-nearest neighbor graph is proposed to protect the geometric structure information and force the latent features to be more concentrated within their classes. Moreover, the layer in the deep architecture to integrate graph regularization is designed to reduce computation cost, and an adaptive decay strategy is considered to adjust the coefficient of graph regularized automatically. A two-stage training algorithm is developed by considering the time to calculate the graph regularization term. Finally, the proposed multi-signal fault diagnosis framework is validated using datasets from the fault injection experiment of similar USMs in China’s Yutu rover of Chang’e lunar probe. Experimental results show that the proposed method can effectively discriminate different fault types.
Characterization of flexural acoustic waves in optical fibers using a fiber-tip interferometer
Authors: Miguel Bello-Jiménez , Erika Hernández-Escobar , Yareli Navarro-Martínez , Rosa López-Estopier , Marco Hernández-Arriaga , Olivier Pottiez , Manuel Durán-Sánchez , Baldemar Ibarra-Escamilla , Miguel Andrés
Published: February 2024

An experimental study using a fiber-tip interferometer (FTI) to characterize traveling flexural acoustic waves (TFAWs) along an optical fiber is reported. The measurements carried out with the FTI are performed following two different procedures: one of them relies on adjusting the interferometer at the quadrature condition and the other extracts the information from the amplitudes of the fundamental and second harmonic of the interference signal. From our measurements, the detection limit of the FTI is 0.5 nm and the upper limit of the linear regime is 30 nm. These results validate the use of the FTI to detect nanometric displacements associated to the amplitude of acoustic waves along an optical fiber. Parameters such as the acoustic wavelength, attenuation coefficient, and phase velocity are measured for a range of acoustic frequencies around the 2 MHz region. Furthermore, and supported by the in-fiber acousto-optic (AO) effect produced by TFAWs, parameters associated to an acoustic wave packet such as the group velocity and the group attenuation coefficient are also determined. This set of experimental results provide useful information of the mechanisms underlying the propagation of TFAWs along an optical fiber and its corresponding AO effect.
Robust procedures in processing measurements in geodesy and surveying: a review
Authors: Duchnowski Robert , Wyszkowska Patrycja
Published: February 2024

Outlying observations are undesirable but possible elements of geodetic measurements. In such a context, the primary and trivial solution is to repeat ‘suspected’ observations. The question arises: what if the measurements cannot be performed again, or if one cannot flag outliers easily and efficiently? In such a case, one should process data by applying methods that consider the possible occurrence of outlying observations. Historically, except for some previous attempts, the statistical approach to robust estimation originates in the 60 s of the 20th century and refers to the pioneer papers of Huber, Tukey, Hampel, Hodges, and Lehmann. Also, the statistical procedures known as data snooping (data dredging) were developed at a similar time. It took not a long time before robust procedures were implemented for processing geodetic observations or adjustment of observation systems. The first works of Baarda and Pope encouraged other scientists or surveyors to elaborate robust procedures adapted for geodetic or surveying problems, which resulted in their rapid development in the last two decades of the 20th century. The question for the 21st century is whether robustness is still an important issue relating to modern measurement technologies and numerical data processing. One should realize that modern geodetic techniques do not decrease the probability of outlier occurrence. Considering measurement systems that yield big data, it is almost certain that outliers occur somewhere. The paper reviews different approaches to robust processing of geodetic observations, from the data snooping methods, random sampling, M-estimation, R-estimation, and Msplitestimation to robust estimation of the variance coefficient. Such a variety reflects different natures, origins, or properties of outliers and the apparent fact that there is no best and most efficient and universal robust approach. The methods presented are indeed the basis for future solutions based on, e.g. machine learning.
Tuning the magnetic properties of hard–soft Ba0.5Sr0.5Fe10Al2O19 and Ni0.1Co0.9Fe2O4 nanocomposites via one pot sol–gel auto combustion method for permanent magnet applications
Authors: Abarna S T , Ezhil Vizhi R
Published: February 2024

Permanent magnets generate magnetic fields that can be sustained when a reverse field is supplied. These permanent magnets are effective in a wide range of applications. However, strategic rare-earth element demand has increased interest in replacing them with huge energy product (BH)max. Exchange-coupled hard/soft ferrite nanocomposites have the potential to replace a portion of extravagant rare earth element-based magnets. In the present, we have reported the facile auto combustion synthesis of exchange-coupled Ba0.5Sr0.5Fe10Al2O19 and Ni0.1Co0.9Fe2O4 nanocomposites by increasing the content of soft ferrite over the hard from x = 0.1 to 0.4 wt%. The XRD combined with Rietveld analysis reflected the presence of hexaferrite and spinel ferrite without the existence of secondary phases. The absorption bands from the Fourier transform infrared spectrum analysis proved the presence of M–O bonds in tetrahedral sites and octahedral sites. Rod and non-spherical images from TEM represent the hexaferrite and spinel ferrite. The smooth M–H curve and a single peak of the switching field distribution curve prove that the material has undergone a good exchange coupling. The nanopowders displayed an increase in saturation magnetization and a decrease in coercivity with the increases in the spinel content. The prepared nanocomposites were showing higher energy products. The composite with the ratio x = 0.2 displayed a higher value of (BH)max of 13.16 kJ m−3.
Passively mode-locked Er-doped fiber laser with single and double wavelength pulses based on germanene saturable absorber
Authors: Ding Jiashuai , Liu Xueyao , Li Tuo , Zou Xiaofeng , Yu Yanfeng , Xu Nannan , Shang Xinxin , Lu Hua , Cheng Chen , Huang Pu , Zhang Huanian , Li Dengwang
Published: February 2024

In this paper, we focus on the single crystal material germanium (Ge), which is fabricated into saturable absorbers (SAs) employing liquid phase exfoliation, and validate it with an erbium-doped fiber laser (EDFL). The Ge SA was obtained with a modulation depth of 9.8% and a saturation intensity of 11.02 MW cm−2. The single-wavelength mode-locked pulse with a minimum pulse width of 847 fs was obtained at a cavity length of 10.5 m. In addition, at a cavity length of 106 m, a dual-wavelength mode-locked phenomenon was obtained in which the central wavelengths were located at 1559.20 nm and 1561.31 nm. The experimental results show that Ge nanosheets in an EDFL provide a strong basis for the development of nonlinear optics and have a wide range of applications in the field of pulsed fiber lasers.
The physical mechanism of stochastic calculus in random walks
Authors: Lee Chern , Ye Hai , Li Hui
Published: February 2024

Stochastic differential equations (SDEs) play an important role in fields ranging from physics and biology to economics. The interpretation of stochastic calculus in the presence of multiplicative noise continues to be an open question. Commonly, the choice of stochastic calculus rules is largely based on empirical knowledge and lacks quantitative substantiation. In this study, we introduce a functional method that quantitatively links stochastic calculus rules to the underlying physical mechanisms in random walks. For a given diffusion coefficient, we construct three models to exemplify the physical features of conventional stochastic calculus. Our work provides a new perspective for quantitatively addressing state-dependent noise and aims to contribute to the understanding of the physical factors underlying uncertainty in SDEs.
The ghost algebra and the dilute ghost algebra
Authors: Nurcombe Madeline
Published: February 2024

We introduce the ghost algebra, a two-boundary generalisation of the Temperley–Lieb (TL) algebra, using a diagrammatic presentation. The existing two-boundary TL algebra has a basis of string diagrams with two boundaries, and the number of strings connected to each boundary must be even; in the ghost algebra, this number may be odd. To preserve associativity while allowing boundary-to-boundary strings to have distinct parameters according to the parity of their endpoints, as seen in the one-boundary TL algebra, we decorate the boundaries with bookkeeping dots called ghosts. We also introduce the dilute ghost algebra, an analogous two-boundary generalisation of the dilute TL algebra. We then present loop models associated with these algebras, and classify solutions to their boundary Yang–Baxter equations, given existing solutions to the Yang–Baxter equations for the TL and dilute TL models. This facilitates the construction of a one-parameter family of commuting transfer tangles, making these models Yang–Baxter integrable.
Constructing universal phenomenology for biological cellular systems: an idiosyncratic review on evolutionary dimensional reduction
Authors: Kaneko Kunihiko
Published: February 2024

The possibility of establishing a macroscopic phenomenological theory for biological systems, akin to the well-established framework of thermodynamics, is briefly reviewed. We introduce the concept of an evolutionary fluctuation–response relationship, which highlights the tight correlation between the variance in phenotypic traits caused by genetic mutations and by internal noise. We provide a distribution theory that allows us to derive these relationships, which suggests that the changes in traits resulting from adaptation and evolution are considerably constrained within a lower-dimensional space. We explore the reasons behind this dimensional reduction, focusing on the constraints posed by the requirements for steady growth and robustness achieved through the evolutionary process. We draw support from recent laboratory and numerical experiments to substantiate our claims. The universality of evolutionary dimensional reduction is presented and potential theoretical formulations for it are discussed. We conclude by briefly considering the prospects of establishing a macroscopic framework that characterizes biological robustness and irreversibility in cell differentiation, as well as an ideal cell model.
Satellite data for environmental justice: a scoping review of the literature in the United States
Authors: Sayyed Tanya Kreutzer , Ovienmhada Ufuoma , Kashani Mitra , Vohra Karn , Kerr Gaige Hunter , O’Donnell Catherine , Harris Maria H , Gladson Laura , Titus Andrea R , Adamo Susana B , Fong Kelvin C , Gargulinski Emily M , Soja Amber J , Anenberg Susan , Kuwayama Yusuke
Published: February 2024

In support of the environmental justice (EJ) movement, researchers, activists, and policymakers often use environmental data to document evidence of the unequal distribution of environmental burdens and benefits along lines of race, class, and other socioeconomic characteristics. Numerous limitations, such as spatial or temporal discontinuities, exist with commonly used data measurement techniques, which include ground monitoring and federal screening tools. Satellite data is well poised to address these gaps in EJ measurement and monitoring; however, little is known about how satellite data has advanced findings in EJ or can help to promote EJ through interventions. Thus, this scoping review aims to (1) explore trends in study design, topics, geographic scope, and satellite datasets used to research EJ, (2) synthesize findings from studies that use satellite data to characterize disparities and inequities across socio-demographic groups for various environmental categories, and (3) capture how satellite data are relevant to policy and real-world impact. Following PRISMA extension guidelines for scoping reviews, we retrieved 81 articles that applied satellite data for EJ research in the United States from 2000 to 2022. The majority of the studies leveraged the technical advantages of satellite data to identify socio-demographic disparities in exposure to environmental risk factors, such as air pollution, and access to environmental benefits, such as green space, at wider coverage and with greater precision than previously possible. These disparities in exposure and access are associated with health outcomes such as increased cardiovascular and respiratory diseases, mental illness, and mortality. Research using satellite data to illuminate EJ concerns can contribute to efforts to mitigate environmental inequalities and reduce health disparities. Satellite data for EJ research can therefore support targeted interventions or influence planning and policy changes, but significant work remains to facilitate the application of satellite data for policy and community impact.
The role of repowering India’s ageing wind farms in achieving net-zero ambitions
Authors: Norman James , Maycock Amanda C , Troccoli Alberto , Dessai Suraje
Published: February 2024

India’s ambitious net-zero climate goals include plans for a four-fold increase in current levels of wind energy generation by 2030. Many existing wind farms in India occupy sites with the best wind resources nationally but use older, smaller turbines that achieve lower capacity factors compared to modern turbine designs. A strategy of replacing existing wind turbines with state-of-the-art models (termed repowering) could boost capacity factors and ensure maximal use of available wind resources. However, a nationwide assessment of the potential wind generation increases resulting from repowering is currently lacking for India. Here, we present the first validated synthetic wind generation dataset for India based on reanalysis data and show that full repowering of the existing fleet of wind turbines could boost capacity factors by 82% nationwide (from 0.19 to 0.35). Our assessment of attainable capacity factors under full repowering exceeds equivalent estimates within the National Electricity Plan of India and national decarbonisation pathways compiled by the Intergovernmental Panel on Climate Change (IPCC), suggesting less total installed capacity is required to achieve specific generation outcomes than previously estimated. Ongoing technological progress, leading to increased turbine dimensions, will drive capacity factors beyond the levels estimated here, which could further add to the generation benefits of repowering. Yet, despite the higher average output from a repowered fleet of wind generators, substantial variability in generation across timescales persists, highlighting the increasing need for power system flexibility within a decarbonised energy system.
Gravitational Landau levels and the chiral anomaly
Authors: Stone Michael , Howland Porter , Kim JiYoung
Published: February 2024

A popular physical picture of the mechanism behind the four-dimensional chiral anomaly is provided by the massless Dirac equation in the presence of constant electric and magnetic background fields. The magnetic field creates highly degenerate Landau levels, the lowest of which is gapless. Any parallel component of the electric field drives a spectral flow in the gapless mode that causes particles to emerge from, or disappear into, the Dirac sea. Seeking a similar picture for the gravitational contribution to the chiral anomaly, we consider the massless Dirac equation in a background spacetime that creates gravitational Landau levels. We find that in this case the resulting spectral flow, with its explicit particle production, accounts for only a small part of the anomalous creation of chiral charge. The balance is provided by the vacuum expectation charge arising from the spectral asymmetry.
The role of intervention mechanisms on a self-organized system: dynamics of a sandpile with site reinforcement
Authors: Sy P B , Batac R C
Published: February 2024

We revisit the sandpile model and examine the effect of introducing site-dependent thresholds that increase over time based on the generated avalanche size. This is inspired by the simplest means of introducing stability into a self-organized system: the locations of collapse are repaired and reinforced. Statistically, for the case of finite driving times, we observe that the site-dependent reinforcements decrease the occurrence of very large avalanches, leading to an effective global stabilization. Interestingly, however, long simulation runs indicate that the system will persist in a state of self-organized criticality (SOC), recovering the power-law distributions with a different exponent as the original sandpile. These results suggest that tipping the heavy-tailed power-laws into more equitable and normal statistics may require unrealistic scales of intervention for real-world systems, and that, in the long run, SOC mechanisms still emerge. This may help explain the robustness of power-law statistics for many complex systems.
Qualitative and quantitative enhancement of parameter estimation for model-based diagnostics using automatic differentiation with an application to inertial fusion
Authors: Milder A L , Joglekar A S , Rozmus W , Froula D H
Published: February 2024

Parameter estimation using observables is a fundamental concept in the experimental sciences. Mathematical models that represent the physical processes can enable reconstructions of the experimental observables and greatly assist in parameter estimation by turning it into an optimization problem which can be solved by gradient-free or gradient-based methods. In this work, the recent rise in flexible frameworks for developing differentiable scientific computing programs is leveraged in order to dramatically accelerate data analysis of a common experimental diagnostic relevant to laser–plasma and inertial fusion experiments, Thomson scattering. A differentiable Thomson-scattering data analysis tool is developed that uses reverse-mode automatic differentiation (AD) to calculate gradients. By switching from finite differencing to reverse-mode AD, three distinct outcomes are achieved. First, gradient descent is accelerated dramatically to the extent that it enables near real-time usage in laser–plasma experiments. Second, qualitatively novel quantities which require

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parameters can now be included in the analysis of data which enables unprecedented measurements of small-scale laser–plasma phenomena. Third, uncertainty estimation approaches that leverage the value of the Hessian become accurate and efficient because reverse-mode AD can be used for calculating the Hessian.
Theory and practice: Defining indirect effects for science and management
Authors: O'Neal Sarah L , Schindler Daniel E , Spanjer Andrew R , Barrett Hannah S , Chow Michelle I , Smits Adrianne P , Evrard Raye , Lee Timothy S
Published: February 2024

Indirect ecological effects—in which interactions of two species are modified by another species or abiotic factor—are generally considered equal to or greater in magnitude than direct effects. The ecological literature describing indirect effects suffers from redundancy and confusion regarding terminology and quantification, limiting its utility to regulators working to estimate indirect relative to direct effects in assessing environmental risks of development. To evaluate consideration for indirect ecological effects in regulatory practice, we reviewed 24 National Environmental Policy Act (NEPA) documents for proposed US mining projects to compare the treatment of indirect effects in the regulatory versus ecological literature. A clear dichotomy between regulatory and academic definitions of indirect effects suggests that NEPA documents overlook scientifically defined ecological impacts of development. Consequently, for scientific inquiry to be useful to regulators and for regulation of development to comprehensively assess risks, multidisciplinary efforts are urgently needed to bridge the gap between ecological science and environmental management.
The clinical significance of indeterminate pulmonary nodules in patients with primary bone sarcoma: a systematic review
Authors: Hassan M Shihabul , Ariyaratne Sisith , Azzopardi Christine , Iyengar Karthikeyan P , Davies Arthur Mark , Botchu Rajesh
Published: February 2024

Objective

To report the incidence of indeterminate pulmonary nodules (IPN) and the rate of progression of IPNs to metastasis in patients with primary bone cancers. We also aimed to evaluate clinical or radiological parameters that may identify IPNs more likely to progress to metastatic disease and their effect on overall or event-free survival in patients with primary bone sarcoma.

Methods

A systematic search of the electronic databases Medline, Embase, and Cochrane Library was undertaken for eligible articles on IPNs in patients with primary bone sarcomas, published in the English language from inception of the databases to 2023. The Newcastle-Ottawa Quality Assessment Form for Cohort Studies was utilized to evaluate risk of bias in included studies.

Results

Six studies, involving 1667 patients, were included in this systematic review. Pooled quantitative analysis found the rate of incidence of IPN to be 18.1% (302 out of 1667) and the rate of progression to metastasis to be 45.0% (136 out of 302). Nodule size (more than 5 mm diameter), number (more than or equal to 4), distribution (bilaterally distributed), incomplete calcification, and lobulated margins were associated with an increased likelihood of IPNs progressing to metastasis, however, their impact on overall or event-free survival remains unclear.

Conclusion

The risk of IPNs progressing to metastasis in patients with primary bone sarcoma is non-negligible. Large IPNs have a high risk to be an actual metastasis. We suggest that IPNs in these patients be followed up for a minimum of 2 years with CT imaging at 3, 6, and 12 month intervals, particularly for nodules measuring >5 mm in average diameter.

Advances in knowledge

This is the first systematic review on IPNs in patients with primary bone sarcomas only and proposes viable management strategies for such patients.
Atrial function after percutaneous occluder device and suture-mediated patent fossa ovalis closure
Authors: Tarsia Carmela , Gaspardone Carlo , De Santis Antonella , D’Ascoli Emanuela , Piccioni Fabiana , Sgueglia Gregory Angelo , Iamele Maria , Leonetti Stefania , Giannico Maria Benedetta , Gaspardone Achille
Published: February 2024

Aims

Suture-mediated patent fossa ovalis (PFO) closure is a recent technique, achieving closure by means of a simple suture. The differences between traditional occluders and suture might have different impacts on atrial function. The aim of this study was to evaluate atrial function after PFO closure by direct suture and traditional occluders.

Methods and results

We prospectively studied 40 patients, 20 undergoing PFO closure by occluder and 20 by suture. Trans-thoracic echocardiography was carried out the day before and 1 year after the procedure. Left atrial (LA) and right atrial (RA) function was evaluated by using speckle-tracking analysis assessing the strain values of the reservoir (st-RES), conduit (st-CD), and contraction phase (st-CT). Compared with values baseline PFO closure, at 1-year follow-up, patients with occluder implantation had significantly worse indices of LA and RA reservoir (LA st-RES P < 0.001; RA st-RES P < 0.001), conduit (LA st-CD P < 0.001; RA st-CD P < 0.001), and contraction function (LA st-CT P < 0.05; RA st-CT P < 0.05). In patients with suture-mediated PFO closure, no significant differences were observed in the same indices of reservoir (LA st-RES P = 0.848; RA st-RES P = 0.183), conduit (LA st-CD P = 0.156; RA st-CD P = 0.419), and contraction function (LA st-CT P = 0.193; RA st-CT P = 0.375).

Conclusion

Suture-mediated PFO closure does not alter atrial function. Conversely, PFO closure by metallic occluders is associated with a deterioration of atrial function. This detrimental effect on atrial function could favour the development of atrial arrhythmias.
Bundling Genetic and Financial Technologies for More Resilient and Productive Small-Scale Farmers in Africa
Authors: Boucher Stephen R , Carter Michael R , Flatnes Jon Einar , Lybbert Travis J , Malacarne Jonathan G , Marenya Paswel P , Paul Laura A
Published: February 2024

Using a multi-year, spatially diversified randomised controlled trial spanning two African countries, this paper explores whether a complementary bundle of genetic and financial technologies can boost the resilience and productivity of small-scale farmers. The analysis shows that both moderate droughts and more severe yield losses undermine the resilience of control-group households, and that these shocks have long-lasting effects as farmers invest and produce less following shocks. Severe yield shocks also increase hunger and food insecurity. The genetic technology—drought-tolerant seeds—provides economically significant protection against mid-season drought and mitigates the long-term drop in farm productivity seen in the control group. The financial technology—satellite-based index insurance—offsets the long-term consequences of severe yield losses that are not mitigated by the drought-tolerant seeds. Finally, the analysis shows that treatment-group farmers who experienced shocks and saw the technologies in action subsequently increased their agricultural investment beyond pre-shock levels, an effect we call the resilience dividend. Unfortunately, this apparent experiential learning cuts both ways. Farmers who did not experience the efficacy of the risk management technologies backed away from using them. Our findings thus showcase how genetic and financial risk-mitigating technologies can offer farmers more complete protection, as well as the challenge of inducing sustained uptake of technologies that are midway between experience and credence goods and only infrequently reveal their benefits.
Questionnaire-based exposome-wide association studies for common diseases in the Personalized Environment and Genes Study
Authors: Lloyd Dillon , House John S , Akhtari Farida S , Schmitt Charles P , Fargo David C , Scholl Elizabeth H , Phillips Jason , Choksi Shail , Shah Ruchir , Hall Janet E , Motsinger-Reif Alison A
Published: February 2024

The exposome collectively refers to all exposures, beginning in utero and continuing throughout life, and comprises not only standard environmental exposures such as point source pollution and ozone levels but also exposures from diet, medication, lifestyle factors, stress, and occupation. The exposome interacts with individual genetic and epigenetic characteristics to affect human health and disease, but large-scale studies that characterize the exposome and its relationships with human disease are limited. To address this gap, we used extensive questionnaire data from the diverse North Carolina-based Personalized Environment and Genes Study (PEGS, n = 9, 429) to evaluate exposure associations in relation to common diseases. We performed an exposome-wide association study (ExWAS) to examine single exposure models and their associations with 11 common complex diseases, namely allergic rhinitis, asthma, bone loss, fibroids, high cholesterol, hypertension, iron-deficient anemia, ovarian cysts, lower GI polyps, migraines, and type 2 diabetes. Across diseases, we found associations with lifestyle factors and socioeconomic status as well as asbestos, various dust types, biohazardous material, and textile-related exposures. We also found disease-specific associations such as fishing with lead weights and migraines. To differentiate between a replicated result and a novel finding, we used an AI-based literature search and database tool that allowed us to examine the current literature. We found both replicated findings, especially for lifestyle factors such as sleep and smoking across diseases, and novel findings, especially for occupational exposures and multiple diseases.