bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogen maser flywheels for optical clocks
Authors: Nemitz N , Hachisu H , Ito H , Ohtsubo N , Miyauchi Y , Morikawa M , Matsubara K , Ido T
Published: November 2024

We consider the statistical and systematic uncertainties that arise from using a hydrogen maser as a flywheel oscillator for an intermittently operating optical clock. Diurnal delay variations observed in the distribution and measurement of the radiofrequency signals are the most significant effects for a clock that repeatedly operates at a similar time of day. In typical operation, we find an overall systematic uncertainty contribution u
B/Lab = 2.0×10−17 for the link between the clock and the reference timescale. Data obtained over more than two years of weekly characterization measurements confirms that the real-world behaviour of the flywheel hydrogen maser is in excellent statistical agreement with our stochastic model.
Robust Optical Clocks for International Timescales (ROCIT)
Authors: Margolis H S , Godun R M , Huntemann N , Le Targat R , Pizzocaro M , Zawada M , Abgrall M. , Akamatsu D , Álvarez Martínez H , Amy-Klein A , Andia M , Benkler E , Bhatt N M , Bilicki S , Bize S , Bober M , Calonico D , Cambier V , Cantin E , Chardonnet C , Cifuentes Marín M , Clivati C , Condio S , Curtis E. A. , Czubla A , Doležal M , Dörscher S , Dunst P , Feng C-H , Filzinger M , Folman R , Fordell T , Formichella V , Foucault Y , Galleani L , Goti I , Groswasser D , Gruszczyński M , Guo C , Hanhijärvi K J , Hausser H N , Hill I R , Hosaka K , Johnson M Y H , Keller J , Klose J , Kobayashi T , Koke S , Kovačić D , Křen P , Kuhl A , Ledziński A , Lemański D , Levi F , Lindvall T , Lisdat C , Liu H , Lodewyck J , Lopez O , Lorini L , Lours M , Mašika P , Mazouth-Laurol M , Mehlstaubler T E , Moreno W , Morzyński P , Narożnik M , Nawrocki J , Nishiyama A , Nogaś P , Nordmann T , Parsons A O , Pointard B , Pottie P E , Risaro M , Robertson B I , Romero González J , Schioppo M , Sesia I , Shang H , Signorile G , Stahl K , Steinel M , Sterr U , Suárez Ramírez J , Tofful A , Tønnes M , Tran A , Tunesi J , Wallin A E , Waterholter T , Zarei M , Zyskind C
Published: November 2024

The recently concluded collaborative European project “Robust optical clocks for international timescales” (ROCIT) tackled some of the key challenges on the roadmap towards a redefinition of the SI second. This paper gives an overview of progress made on improving the robustness and automation of optical clocks and verifying their uncertainty budgets through coordinated international comparison campaigns. It also presents work on the incorporation of optical clocks into time scales, covering both their use to steer local physical time scales and their use for evaluations of hydrogen masers contributing data for the computation of International Atomic Time (TAI). The overall objective of the project was to bring European optical clocks to the stage where they could be operated routinely as secondary frequency standards, regularly contributing to TAI.
Atom Fountains at NTSC
Authors: Ruan Jun , Wang Xinliang , Zhang Hui , Liu Dandan , Guan Yong , Shi Junru , Bai Yang , Fan Sichen , Hao Qiang , Nie Shuai , Lei Pengyue , Zhu Ziyi , Zhang Shougang
Published: November 2024

Atom fountains as primary frequency standard (PFS) and continuously operated clocks have been developed to improve the local time scale at the National Time Service Center (NTSC), Chinese Academy of Sciences. Cesium fountain NTSC-CsF2 as PFS showed that the type B uncertainty was evaluated at 4.3 × 10−16. Frequency comparisons were completed between NTSC-CsF2 and the SI second through a GNSS link for 14 months, the results of which were consistent with those of the other fountains within the uncertainty. A cryogenic Cs fountain is being developed to reduce the blackbody radiation shift (BBR) and verify the BBR theory. An Rb fountain clock NTSC-RbF1 was operated to generate local and EAL time scale. The frequency drift was reduced by maintaining a stable vapor pressure. NTSC-RbF2 features a more robust optical system consisting of all fiber-optical components and an ultra-stable OCXO as a local oscillator. An instability time scale below 100 ps is expected based on the Rb atom fountain clocks.
Compact and Robust Laser System for a Transportable Strontium Optical Lattice Clock
Authors: Muramatsu T , Hiroki T , Sakai Y , Hisai Y , Furumiya T , Uno S , Tojo K , Takamoto M , Katori H
Published: November 2024

We developed a laser system for a Sr optical lattice clock to down-size and improve robustness and maintainability. The optics were fixed by laser welding to prevent misalignment during transportation and operation. The volume of the laser system was reduced by removing adjustable mechanisms and integrating multi-function electronics. By utilizing the developed laser system, the volume of optical lattice clocks was down to 250 L.
Sr Optical Lattice Clock and Precision Optical Frequency Measurement at NIM
Authors: Yang T. , Lu B. , Zhu L. , Liao T. , Wang Q. , Li Y. , Meng F. , Lin B. , Wang Y. , Fang F. , Lin Y. , Fang Z.
Published: November 2024

Two Sr optical lattice clocks are being built at the National Institute of Metrology of China (NIM). Sr1 was built on NIM’s Hepingli Campus. It was first evaluated in 2015 and improved later on. In 2021, the systematic shift uncertainty of Sr1 was evaluated to be 2.9 × 10−17. Sr2 was started to be built on NIM’s Changping Campus in 2017. The systematic shift uncertainty of Sr2 was evaluated to be 7.2 × 10−18 in 2022. With a new BBR optimizing process, the total BBR uncertainty of Sr2 is reduced to 4.6 × 10−18 which corresponds to the total uncertainty of Sr2 is evaluated to 6.5 × 10−18 in 2023. To compare these two Sr clocks, an optical frequency transfer fiber link with a length of 54 km was established between these two clocks. A preliminary study of generating a local time scale with Sr1 has been carried out at NIM. The time scale generated by post-processing of the comparison data between Sr1 and an H-maser demonstrated better stability than the time scale steered by UTC.
High-accuracy multi-ion spectroscopy with mixed-species Coulomb crystals
Authors: Keller J. , Hausser H. N. , Richter I. M. , Nordmann T. , Bhatt N. M. , Kiethe J. , Liu H. , Benkler E. , Lipphardt B. , Dörscher S. , Stahl K. , Klose J. , Lisdat C. , Filzinger M. , Huntemann N. , Peik E. , Mehlstäubler T. E.
Published: November 2024

Multi-ion optical clocks offer the possibility of overcoming the low signal-to-noise ratio of single-ion clocks, while still providing low systematic uncertainties. We present simultaneous spectroscopy of up to four 115 In+ clock ions in a linear Coulomb crystal, sympathetically cooled with 172Yb+ ions. In first clock comparisons, we see agreement below 1 × 10−17 with results obtained using a single In+ ion, for which we have evaluated the systematic uncertainty to be 2.5 × 10−18. Operation with four clock ions reduces the instability from

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to

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. We derive a model for decay-related dead time during state preparation, which matches the observed scaling of instability with clock ion number N, and indicates that

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N

scaling can be achieved with the addition of a repump laser.
Towards a sub-kelvin cryogenic Fabry-Perot silicon cavity
Authors: Barbarat Joannès , Gillot Jonathan , Millo Jacques , Lacroûte Clément , Legero Thomas , Giordano Vincent , Kersalè Yann
Published: November 2024

We report on the development of a sub-kelvin, single-crystal silicon Fabry-Perot cavity. Operating such a cavity below 1 K should reduce the thermal noise limit of the cavity, and by this way address the current limitations of ultrastable lasers. To further decrease mechanical losses, mirrors with silicon substrates and crystalline coatings are optically contacted to the spacer, resulting in a room-temperature finesse of 220,000. To operate our cavity at sub-kelvin temperatures, we use a dilution refrigerator able to reach temperatures down to 10 mK. We have designed a mechanical mount to house our cavity in such a cryostat, with optimized heat transfer that will decrease the cooldown time for temperatures below 1 K. The estimated thermal noise is projected to be ∼ 7×10−19 at 100 mK. However, silicon cavities with crystalline mirror coatings at cryogenic temperatures have shown birefringence correlated frequency fluctuations as well as unknown additional noise mechanisms [1, 2]. We have measured a room-temperature TEM00 birefringent mode splitting of about 250 kHz. Understanding and measuring these noise mechanisms will be a key to attaining fractional frequency stabilities beyond state-of-the-art.
Crystal Grain Rotation during Tensile Test of Polycrystalline Pure Titanium Thin Sheet Based on Surface Height and Crystal Orientation
Authors: Tada Naoya , Ohashi Hiroaki , Uemori Takeshi , Sakamoto Junji
Published: November 2024

Thin sheets and wires of polycrystalline pure titanium are important materials for various devices used in electrical, mechanical, dental, and medical fields. Since pure titanium shows strong anisotropy in elastic and plastic deformation, and the individual grains comprising a polycrystalline body have different orientations and geometries, inhomogeneous deformation always occurs on the microscopic scale. This inhomogeneity is more significant in thin films than in bulk materials. It is therefore important to investigate the inhomogeneous deformation of pure titanium thin sheets to ensure the reliability of various titanium devices. In this study, thin-sheet specimens made of polycrystalline pure titanium were subjected to tensile testing. Inhomogeneous deformation was evaluated on the basis of two kinds of crystal grain rotations based on surface height and crystal orientation. The results under elastic and plastic tensile conditions were compared.
A User Satisfaction Enhancement Method for Low-Carbon Electromechanical Products Based on Design Knowledge Graphs
Authors: Wang Zhenzhe , Zhu Shuo , Jiang Zhigang , Yan Wei , Zhang Hua , Zhou Tingting
Published: November 2024

Enhancing user satisfaction is crucial for the widespread adoption of low-carbon electromechanical products. However, the low-carbon design of electromechanical products involves multiple aspects, such as product functionality, structural design, and material selection, each needing to balance user performance needs with low-carbon characteristics. Traditional methods often struggle to optimize these design aspects simultaneously, leading to lower market acceptance and reduced product competitiveness. To address this, a method for improving user satisfaction with low-carbon electromechanical products based on a design knowledge graph is proposed. This method starts with analyzing the design process of the product’s function, structure, and materials to filter out design knowledge that meets user needs through performance satisfaction and carbon emissions evaluations. It then constructs a design knowledge graph and employs a graph optimization algorithm to efficiently explore product structure and material information, generating and recommending solutions that optimize performance satisfaction and cost. Finally, a typical home appliance refrigerator is taken as an example to verify the effectiveness of the proposed method.
The effect of Al on microstructure and properties of Cu-15Ni-8Sn during the aging
Authors: Hong Songbai , Luo Wei , Wang Dongya , Luo Yi , Li Xuehua , Liu Feng
Published: November 2024

In this paper, microstructure evlution, hardness and tensile properties of Cu-15Ni-8Sn-(0.5Al) alloys during aging at 500°C were investigated in detail. The results showed that the grain was refined and the elongation of alloy at solid solution was improved with the additon.of Al. The DO22 ordered phase was suppressed during aging in the Cu-15Ni-8Sn-0.5Al alloy, while the L12 ordered phase stability was significantly improved. Therefore, the L12 ordered phase was not consumed by the discontinuous precipitation (DP) reaction during the prolonged aging process, which effectively suppressed the development of DP and improved the resistance to over-aging of the alloy. However, Al also leads to a serious decrease in the plasticity of Cu-15Ni-8Sn alloys, which has no yield point during tensile process after aging for 1h.
Investigation of ballistic performance of aramid fabrics modified by polyethylene and graphene in high temperature and humidity environments
Authors: Liu Peng , Wang Zhe , Zhang Hong , Huang Guangyan
Published: November 2024

In today’s world, conflicts are constant, and the environment in world is complex and diverse. The aging of bulletproof vests has become increasingly important. To investigate the environmental adaptability of polyethylene and graphene modified aramid fabrics, this study subjected the modified fabrics to high-temperature and humidity cycling treatments, followed by ballistic experiments to compare the ballistic limits of the fabrics. Various environmental factors affecting the ballistic performance of different fabrics were analyzed. The experimental results indicate that the ballistic performance of pure aramid fabrics is minimally affected by temperature and humidity, demonstrating strong stability. As the temperature increases, the ballistic limits of the modified fabrics gradually decrease; however, the decline is relatively small, at only 9.5%. The use of graphene can resist the effects of humidity and heat to some extent: under 120°C and humidity cycling conditions, the graphene modified fabric outperforms the polyethylene modified fabric. Furthermore, temperature has almost no effect on the failure modes of the various fabrics.
Aerodynamic and aeroacoustic analysis of a model UAV propeller
Authors: Szulc O , Flaszyński P , Suresh T
Published: November 2024

The paper summarizes the development and validation of an in-house Ffowcs-Williams and Hawkings (FW–H) aeroacoustic solver and its application to a low-Reynolds number two-bladed model propeller of an Unmanned Aerial Vehicle (UAV) investigated experimentally at TUD (Technical University of Delft). It is based on Farassat’s Formulation 1A of the solution to FW–H acoustic analogy allowing for harmonic and broadband noise analysis (monopole and dipol contributions). Initially, the validation process is presented for elementary rotating and fluctuating momentum sources (forces) with available analytical solutions. Next, the propeller of TUD is simulated with block-structured, compressible flow solver FLOWer (DLR, Germany) based on RANS/SALSA (Strain Adaptive Linear Spalart-Allmaras) and DES/k–ω SST (Shear-Stress Transport) approaches to turbulence modeling and with the second and fourth-order numerical schemes. The predicted rotor aerodynamic performance is compared against the experimental data (tripped cases only) for rotational speed of 5000 RPM (tip Mach number of 0.23) and wide range of advance ratio J. Finally, for hover conditions (J = 0) and an in-plane observer location, the predicted surface pressure fluctuations are used as input for FW–H acoustic analysis and the resultant propeller Sound Pressure Level (SPL) signature is compared with the measured spectrum.
Validation of Yamaguchi-Ichikawa water hammer model
Authors: Urbanowicz K , Di Nucci C , Sharma B K , Ashok K , Krajewski S
Published: November 2024

This study comprehensively analyses the Yamaguchi-Ichikawa (YI) model for water hammer phenomena in hydraulic systems, alongside recent theoretical studies and experiments. While promising initially, comparative investigations reveal limitations in the YI model’s alignment with experimental data, particularly regarding initial conditions and pulsation periodicity. These shortcomings, including the absence of a phase shift, may hinder its applicability in complex pressure systems with multiple wave reflections. The research focuses on analyzing analytical models that describe the phenomenon of water hammer. These models enable the proposal of future research directions, integrating theoretical models with experimental observations.
Revisiting homogeneous modeling with volume averaging theory: structured catalysts for steam reforming and CO2 methanation
Authors: Medina Méndez J A , Dorneanu B , Schmidt H , Arellano-García H
Published: November 2024

Progress in the modeling of structured catalysts is crucial for enhancing efficiency and scalability in industrial applications. Extensive research has investigated reactive flows over catalyst surfaces, covering chemical kinetics analysis and (direct) numerical simulations of the complete fluid flow in fixed-bed or structured catalysts. Nonetheless, this comes at a high computational cost. This study focuses on the homogeneous modeling of structured catalysts utilizing volume-averaging theory (VAT) as a more efficient method for representing the behaviour of such systems. We discuss modeling strategies for both 1-D and 3-D simulations. For steady 1-D flow simulations, we assess the influence of simplified gas chemical kinetics versus detailed surface chemistry, comparing with experimental data from the literature for a CO2 methanation processes. We also simulate 3-D flows of a steam reforming process, previously studied in the literature, using models which rely on different assumptions regarding the nature of the porous catalyst. Our findings reveal significant discrepancies based on different modeling assumptions, underscoring the necessity for accurate modeling of permeability and diffusivity tensors in homogeneous models.
Numerical investigation of fill height and secondary currents in an inclined partially filled pipe flow
Authors: Bose Aniruddha , Borman Duncan J , Hunter Timothy N , Spencer Julian T , Cunliffe Christopher J
Published: November 2024

Partially filled pipes are used in industrial processes to transport liquid and particle laden flows. A good understanding of the three-dimensional flow in these pipes is critical to ensure material is transported without issue, for example without particulates settling out. In this work, air-water two-phase flows in a partially filled pipe geometry of an industrial slurry transport rig are investigated using unsteady Volume of Fluid (VOF) RANS model in OpenFOAM to investigate fill height and secondary currents. Both are important factors in partially filled pipes where the water depth and secondary current strength can influence solid particle transport and settling. The study confirms that the CFD approach can reliably predict the flow depth across a range of pipe inclination and the secondary currents are predicted in good qualitative agreement with those seen in other studies. The effect of pipe inclination on fill height and the effect of fill height on secondary currents are investigated for a range of mass flow rates. The results of fill height agree well with the experiments and are in line with the Manning equation for a hydraulically smooth pipe. Secondary current strength is seen to increase with fill height in agreement with other studies.
Numerical investigation of local aerosol deposition in a real scale T-junction of a ventilation network
Authors: Ploix R. , Gehin E. , Malet J.
Published: November 2024

Local particle deposition measurements in a T-junction of a real scale ventilation network are studied and interpreted using RANS CFD simulations. To assess the validity of the simulation, an analysis of the flow at different scales is proposed. The experimental results show a particle deposition tendency to be higher downstream the T-junction and particularly on the outer side of the T-junction. This tendency appears to be linked to a separation downstream the T-junction, with the main flow on the outer side of the junction and secondary flow on the inner side. This separation seems to have an impact on the aerosol repartition in the bulk, which can be linked to aerosol concentrations gradient downstream the T-junction.
Anisotropic turbulence in marine cumulus clouds
Authors: Król Stanisław , Malinowski Szymon
Published: November 2024

Clouds are complex phenomena present in the atmospheric flows, with different physical processes influencing them at various scales. Among these processes is turbulent mixing, one of the main contributors to the transport of physical quantities. Turbulence is often, for simplicity, assumed to be homogeneous and isotropic, however numerous observations indicate that it is not always the case. This motivates the studies of deviations from Kolmogorov theory of homogeneous and isotropic turbulence. In this work, time series of air velocity fluctuations collected by airborne measurements of marine cumulus clouds are studied using anisotropy invariant maps. The results show that turbulence in such conditions is often anisotropic, and there are some differences in anisotropy inside clouds and at their edges.
Analysis and actuation design of a novel at-scale 3-DOF biomimetic flapping-wing mechanism inspired by flying insects
Authors: Wang Liang , Zhang Hongzhi , Zhang Longlong , Song Bifeng , Sun Zhongchao , Zhang Wenming
Published: November 2024

Insects’ flight is imbued with endless mysteries, offering valuable inspiration to the flapping-wing robots. Particularly, the multi-mode wingbeat motion such as flapping, sweeping and twisting in coordination presents advantages in promoting unsteady aerodynamics and enhancing lift force. To achieve the flapping-twisting-sweeping motion capability, this paper proposes an at-scale three-degree-of-freedom (3-DOF) mechanism driven by three piezoelectric actuators, which consists of three four-bar mechanisms and a parallel spherical mechanism. Compliant hinges are utilized as rotating joints for power transmission. The DOF and the kinematics analysis are performed. The aerodynamic model of the wing and the mechanical model of the compliant hinges are considered to investigate the required driving force response of the mechanism with wing loads. By employing nonlinear programming techniques, the geometric parameters of three piezoelectric actuators are reverse-designed to match the dynamic response of the mechanism in two flapping conditions. The significance of this work lies in proposing a novel concept of an at-scale multi-DOF wingbeat mechanism, demonstrating the feasibility of this mechanism to mimic the flexible and multi-mode wingbeat movement of insects, and providing an initial mechanism-drive solution.
Genetic algorithm-based optimal design for fluidic artificial muscle (FAM) bundles
Authors: Duan Emily , Bryant Matthew
Published: November 2024

In this paper, we present a design optimization framework for a fluidic artificial muscle (FAM) bundle subject to geometric constraints. The architecture of natural skeletal muscles allows for compact actuation packaging by distributing a substantial number of actuation elements or muscle fiber motor units, which are to be arranged, oriented, and sized in various formations. Many researchers have drawn inspiration from these natural muscle architectures to assist in designing soft robotic systems safe for human-robot interaction. Although there are known tradeoffs identified between different muscle architectures, this optimization framework offers a method to map these architectural tradeoffs to soft actuator designs. The actuation elements selected for this study are FAMs or McKibben muscles due to their inherent compliance, cheap construction, high force-to-weight ratio, and muscle-like force-contraction behavior. Preceding studies analytically modeled the behavior of arranging FAMs in parallel, asymmetrical unipennate, and symmetrical bipennate topologies inspired by the fiber architectures found in human muscle tissues. A more recent study examined the implications of spatial constraints on bipennate FAM bundle actuation and found that by careful design, a bipennate FAM bundle can produce more force, contraction, stiffness, and work output than that of a parallel FAM bundle under equivalent spatial bounds. This multi-objective genetic algorithm-based optimization framework is used to realize desirable topological properties of a FAM bundle for maximum force and stroke for a given spatial envelope. The results help identify tradeoffs to inform design decisions based on the force and stroke demand from the desired operating task. This study further demonstrates how the desirable topological properties of the optimized FAM bundle change with different spatial bounds.
Exploring conditions for just lithium mining in South America. The case of the EU responsible sourcing strategy
Authors: Murguía Diego I , Obaya Martín
Published: November 2024

To advance its climate neutrality and electromobility goals, the European Union (EU) depends on a reliable supply of lithium. The “lithium triangle”, comprising Chile, Argentina, and Bolivia, contains 53% of the world’s lithium resources and supplies 85% of the EU’s lithium imports. In 2023, the EU and Latin America launched a new cooperation agenda under which the EU signed Memorandums of Understanding (MoUs) with Chile and Argentina aimed at jointly developing sustainable value chains for critical raw materials. That same year, the EU adopted the European Batteries Regulation (EBR), which mandates due diligence to address social and environmental risks in the mining of battery minerals. The EBR and MoUs form the foundation of the EU’s responsible sourcing strategy for lithium from South America. This study, using the energy justice framework and results from a Delphi survey, investigates whether the EBR and MoUs align with the conditions for a just lithium battery value chain for the lithium triangle. Our findings indicate that the EU-South America agenda reflects cumulative learning by addressing mutual interests, such as local industrialization. However, the current EU responsible sourcing approach overlooks critical local-level justice considerations —distributive, procedural, and recognition justice— that are highly relevant to the lithium triangle. We argue that for the EU to ensure a just lithium supply from South America, additional issues must be prioritized, including the equitable participation of local communities in the economic benefits of lithium mining, institutional strengthening, and the proper implementation of free, prior, and informed consultation with Indigenous peoples.
How the Russian–Ukrainian war reshapes the climate policy context
Authors: Harmsen Mathijs , Fragkiadakis Dimitris , Fragkos Panagiotis , Vu An , Fazekas Dora , de Boer Harmen-Sytze , Dafnomilis Ioannis , den Elzen Michel , Hartvig Áron , Bui Ha , Hooijschuur Elena , van Vuuren Detlef
Published: November 2024

The Russian military aggression against Ukraine has had significant global impacts on energy security, economy and geopolitics. The 2022 global energy crisis raises questions about how the war affects the energy transition and global climate policy. However, there are limited studies that incorporate its effects into self-consistent projections of alternative scenarios. This scenario study uses two leading macro-economic models and one integrated assessment model to assess how the war in Ukraine and its direct implications—trade restrictions and rising energy prices—affect economies, energy supply and demand trends, emissions and the feasibility of climate policies. The models consistently project that the disruptive responses to the war lead to a shift from fossil fuels (notably natural gas) to renewable energy and a consequent CO2 emission reduction of about 1%–5%, in the period up to 2050, both for the European Union and globally. However, projections differ across models in terms of sectoral and regional contributions to emission reductions. The results are found to be highly sensitive to the expected, yet uncertain persistence of higher fossil energy prices due to the war, which depends on the duration of the conflict, the disruption of global energy supplies and the response of other major fossil fuel exporters.
Locally unitary quantum state evolution is local
Authors: Heikkilä Matias
Published: November 2024

We study the localization properties of bipartite channels, whose action on a subsystem yields a unitary channel. In particular we show that, under such channel, the subsystem must evolve independent of its environment. This point of view is another way to verify certain well-known conservation laws of quantum information in a generalized way. A no-go theorem for non classical conditional semantics in quantum computation is obtained as an intermediate result.
Taylor’s Law from Gaussian diffusions
Authors: Eliazar Iddo
Published: November 2024

Taylor’s Law, also known as fluctuation scaling, manifests a power relation between the means and the variances of statistical distributions. The class of Gaussian-selfsimilar stochastic motions offers a plethora of macroscopic diffusion models, regular and anomalous alike. This class includes Brownian motion, scaled Brownian motion, fractional Brownian motion, and more. Within this class, power Brownian motion (PBM) is the sub-class of motions that are also Markovian. Considering conditional distributions of motion positions, this paper establishes that: the Gaussian-selfsimilar class universally generates Taylor’s Law, doing so with both positive and negative Taylor exponents. The paper also unveils a profound interplay between PBM and the universal generation of Taylor’s Law from the Gaussian-selfsimilar class.
Differential sensing approaches for scattering-based holographic encryption
Authors: Taghavi Mohammadrasoul , Marengo Edwin A
Published: November 2024

We develop a new scattering-based framework for the holographic encryption of analog and digital signals. The proposed methodology, termed ‘differential sensing’, involves encryption of a wavefield image by means of two hard-to-guess, complex and random scattering media, namely, a background and a total (background plus scatterer) medium. Unlike prior developments in this area, not one but two scattering media are adopted for scrambling of the probing wavefields (as encoded, e.g. in a suitable ciphertext hologram) and, consequently, this method offers enhanced security. In addition, while prior works have addressed methods based on physical imaging in the encryption phase followed by computational imaging in the decryption stage, we examine the complementary modality wherein encryption is done computationally while decryption is done analogically, i.e. via the materialization of the required physical imaging system comprising the ciphertext hologram and the two unique (background and total) media. The practical feasibility of the proposed differential sensing approach is examined with the help of computer simulations incorporating multiple scattering. The advantages of this method relative to the conventional single-medium approach are discussed for both analog and digital signals. The paper also develops algorithms for the required in situ holography as well as a new wavefield-nulling-based approach for scattering-based encryption with envisioned applications in real-time customer validation and secure communication.
What were they growing?
Authors: Davies Wendy
Published: November 2024

This chapter surveys all currently available macrobotanical data on specific cultivated plants from northern Iberia from the late Roman period to the eleventh century. Cereals, legumes, forage, flax, fruits, nuts, and herbs are standard throughout, but there is some regional variation, with a greater range of cultivated plants in Catalonia and Portugal—extending to include mulberries, almonds, peaches, and olives, and herbs like celery, black mustard, parsley, and verbena. Macrobotanical results are supported by some pollen data. Determining how much of this product was grown in gardens is not straightforward but the indications combine to suggest that legumes and fruit were standard horticultural products, with an additional patch of flax or cereals or alfalfa or vines always possible.
Questions remaining
Authors: Davies Wendy
Published: November 2024

Comparison with western Europe and al-Andalus suggests that garden product was more varied there than in northern Iberia in the early middle ages and gardens in northern Spain and Portugal do not seem to have matched the idealized monastic picture. However, northern Iberia was not a homogeneous zone, having strong cultural as well as geographic variations; there were therefore complex patterns of difference between its constituent regions with regard to garden practice. The reasons for these regional differences are explored in this chapter, involving investigation of socio-economic structures, ecclesiastical proprietorship, commercial enterprise, and relationships with al-Andalus. Supply of urban communities and urban visitors was important, through local networks, including supply of cloth and clothing. Gardens were essential for textile fibres and dye plants.
Multiple abscesses and plaques in an immunocompetent patient
Authors: Fanous Noah , Clarke Emily , Nguyen Khang D
Published: November 2024

A 40-year-old immunocompetent man experiencing housing insecurity presented with a 2-week history of fluctuant abscesses on the left forehead and supraorbital area that became crusted scaly plaques, a pink plaque on the right dorsal hand and a necrotic ulcer on the right great toe; all were resistant to 2 weeks of doxycycline. A shave biopsy of a new plaque on the right cheek revealed large, broad-based fungal yeast forms and concomitant right middle lobe consolidating pneumonia.
Human Immunodeficiency Virus 1 Low-Level Viremia Predicts Viral Failure in Participants on Antiretroviral Therapy in the Swiss HIV Cohort Study
Authors: Lanz Caroline , Meier Jan , Stöckle Marcel , Furrer Hansjakob , Calmy Alexandra , Cavassini Matthias , Bernasconi Enos , Schmid Patrick , Braun Dominique L , Kouyos Roger D , Loosli Tom , Kusejko Katharina , Günthard Huldrych F ,   the Swiss HIV Cohort Study, Abela I , Aebi-Popp K , Anagnostopoulos A , Battegay M , Bernasconi E , Braun D L , Bucher H C , Calmy A , Cavassini M , Ciuffi A , Dollenmaier G , Egger M , Elzi L , Fehr J , Fellay J , Furrer H , Fux C A , Günthard H F , Hachfeld A , Haerry D , Hasse B , Hirsch H H , Hoffmann M , Hösli I , Huber M , Jackson-Perry D , Kahlert C R , Keiser O , Klimkait T , Kouyos R D , Kovari H , Kusejko K , Labhardt N , Leuzinger K , Martinez de Tejada B , Marzolini C , Metzner K J , Müller N , Nemeth J , Nicca D , Notter J , Paioni P , Pantaleo G , Perreau M , Rauch A , Salazar-Vizcaya L P , Schmid P , Segeral O , Speck R , Stöckle M , Tarr P , Trkola A , Wandeler G , Weisser M , Yerly S
Published: November 2024

Background

Most individuals receiving combination antiretroviral therapy (ART) have human immunodeficiency virus (HIV) plasma viral loads below the limit of detection. However, episodes of low-level viremia (LLV) are observed in subsets of individuals, the risk factors and clinical significance of which remain debated.

Methods

We included participants enrolled in the Swiss HIV Cohort Study, starting ART between July 1999 and April 2023, with HIV RNA values <200 copies/mL 6 months after ART initiation. Using longitudinally collected data, we applied a time-updated Cox proportional hazards model to determine the association of LLV with the risk of subsequent viral failure, defined as ≥200 copies/mL. LLV was quantified by the time-updated area under the curve (AUC) of HIV RNA values, categorized as undetectable or, based on AUC tertiles, low, intermediate, or high.

Results

We included 8132 participants with a total of 49 579 person-years of follow-up. The median follow-up time was 4.7 years, and the median number of HIV RNA measurements was 16. Participants had a median age of 38 years, 75.9% were male, 74.4% were white, and 45.9% had HIV-1 subtype B. LLV was associated with an increased risk of subsequent viral failure, with the highest LLV category showing the strongest association (hazard ratio, 3.3 [for comparison with undetectable viral load]) among all included variables, including race/ethnicity, age, and ART.

Conclusions

LLV was strongly associated with risk of subsequent viral failure, even after adjustment for demographic and clinical characteristics, including adherence and treatment regimen. The detection of LLV should prompt appropriate measures to decrease the risk of subsequent viral failure.
Impact of HLADQA1*05 and HLADQA1*03 on Safety and Loss of Response to Anti-Tumor Necrosis Factor in Patients With Inflammatory Bowel Disease
Authors: López De-La-Cruz Julia , Gomollón Fernando , Louro Javier , López Pérez Juan , Nocito Colon María Mercedes , Gallego Llera Beatriz , García-Mateo Sandra , Martínez-Domínguez Samuel J , Aso Gonzalvo María Concepción , Gargallo-Puyuelo Carla J
Published: November 2024

Background

HLADQA1*05 is recently associated with heightened immunogenicity to anti-tumor necrosis factor (TNFα). We aimed to determine whether HLADQ1*05 is a risk factor for primary non-response, loss of response (LOR), or adverse events (AE) to first-line anti-TNFα in patients with inflammatory bowel disease.

Methods

We performed a retrospective observational study enrolling biologic naïve patients with Crohn’s disease and ulcerative colitis who initiated adalimumab or infliximab from 2000 to 2021. HLA-DQA1 genotype was determined in all patients and immunogenicity in 98 patients.

Results

We enrolled 408 patients who started first-line infliximab (n = 211) and adalimumab (n = 197), with a mean follow-up of 7.6 years. Primary response at Week 24 occurred in 347 (85.0%), LOR in 133 (38.3%), and AE in 93 (22.8%). The HLADQA1*05 was identified in 185 (43.3%) patients. In multivariate analyses, no risk factors were identified for primary response. HLADQA1*05 was an independent risk factor for LOR (adjusted hazard ratio [aHR] = 1.80, 95% CI = 1.21-2.67) and immunogenicity (aOR = 3.44, 95% CI = 1.12-11.92). HLADQA1*03 was a protective factor against LOR (aHR = 0.42, 95% CI = 0.20-0.88). Stratified analysis by anti-TNF type showed that HLADQA1*05 increased the risk of LOR to infliximab but not to adalimumab and HLADQA1*03 decreased the risk of LOR to adalimumab but not to infliximab. Female sex, infliximab, and the co-presentation of at least one allele of the HLADQA1*03 and HLADQA1*05 were risk factors for AE.

Conclusions

HLADQA1*05 is associated with a higher risk of LOR and immunogenicity, particularly to infliximab. HLADQA1*03 seems to play a protective role against LOR, particularly adalimumab. Female sex and infliximab are risk factors for AE.
Temporal control of Staphylococcus aureus intracellular pH by sodium and potassium
Authors: Hilliard Julia K , Gries Casey M
Published: November 2024

Adaptation to environmental change during both colonization and infection is essential to the pathogenesis of Staphylococcus aureus. Like other bacterial pathogens that require potassium to fulfill nutritional and chemiosmotic requirements, S. aureus has been shown to utilize potassium transport to modulate virulence gene expression, antimicrobial resistance, and osmotic tolerance. Recent studies examining the role for potassium uptake in mediating S. aureus physiology have also described its contribution in mediating carbon flux within central metabolism and generation of a proton motive force. Here, we utilize a pH-sensitive green fluorescent protein to examine the temporal regulation of S. aureus intracellular pH by potassium and sodium under various environmental conditions, including extracellular pH and antibiotic stress. Our results distinguish unique conditions and transport mechanisms that utilize these ions to modulate cytoplasmic pH homeostasis, and they identify these processes as a novel mechanism of intrinsic ampicillin resistance in S. aureus.
Spatiotemporal forecast of extreme events in a chaotic model of slow slip events
Authors: Kaveh Hojjat , Avouac Jean Philippe , Stuart Andrew M
Published: November 2024

Seismic and aseismic slip events result from episodic slips on faults and are often chaotic due to stress heterogeneity. Their predictability in nature is a widely open question. In this study, we forecast extreme events in a numerical model. The model, which consists of a single fault governed by rate-and-state friction, produces realistic sequences of slow events with a wide range of magnitudes and interevent times. The complex dynamics of this system arise from partial ruptures. As the system self-organizes, the state of the system is confined to a chaotic attractor of a relatively small dimension. We identify the instability regions within this attractor where large events initiate. These regions correspond to the particular stress distributions that are favourable for near complete ruptures of the fault. We show that large events can be forecasted in time and space based on the determination of these instability regions in a low-dimensional space and the knowledge of the current slip rate on the fault.
Addressing the commercial determinants of menstrual health: a call to regulate menstrual product manufacturers
Authors: Brassart Olsen Céline
Published: November 2024

Over the last two decades, menstrual health and hygiene have become increasingly common on the global health agenda. While governments and international organizations are adopting measures to make menstrual products more accessible, corporate actors producing them have only been subject to limited scrutiny. Yet, their products and commercial practices raise environmental, health, equity and societal issues, which warrant attention and regulation. As such, commercial disposable menstrual products are largely made up of plastic, sometimes as much as 90%. Menstrual pads and tampons also contain some chemicals, the health impact of which is still unclear. In addition, these products are often sold with high-profit margins, and marketing campaigns to sell such products tend to reinforce shame and secrecy. So far, no global standards exist to regulate menstrual products and manufacturers, and evidence in the field of menstrual health and hygiene is lagging behind. To fill this gap, countries have started to regulate menstrual products and the International Standards Organization is in the process of developing global standards to better regulate the content and labeling of menstrual products. To support the emergence of regulation in this area, this article conceptualizes for the first time a comprehensive framework for the regulation of menstrual product manufacturers. This framework encompasses five complementary measures to regulate the content; labeling; production and waste management; pricing; advertising and marketing of menstrual products. The article also calls for more research to produce evidence and for increased governmental and inter-governmental attention to menstrual product manufacturers.
Contextual factors impacting WHO Framework Convention on Tobacco Control implementation in Africa—a scoping review
Authors: Bandara Shashika , Phiri Masauso Moses , Magati Peter , Drope Jeffrey , Adams Alayne , Hunt Matthew , Lencucha Raphael
Published: November 2024

According to the World Health Organization (WHO), tobacco use causes over 8 million deaths annually including 1.3 million due to second-hand exposure. Furthermore, data from the Tobacco Atlas show that the tobacco industry continues to target new markets in the WHO African region, one of two regions where absolute numbers of smokers continue to increase. Understanding context contributes to policy formulation and implementation ensuring relevance to a country’s political economy. Focusing on the WHO African region, this scoping review (i) maps the extent of academic research examining contextual factors on the WHO Framework Convention on Tobacco Control (WHO FCTC) national-level implementation, and (ii) reports on contextual factors impacting the WHO FCTC implementation. Using a stepwise structured approach, we conducted a search across four academic databases, yielding 10 342 articles and 42 were selected for full data extraction. Leichter’s four categories of context (situational, structural, cultural and exogenous) and the stages of heuristic policy model guided data extraction. Study findings indicated that situational contextual factors such as the burden of disease or its impact on health can push governments toward policy formulation. Structural contextual factors included political considerations, economic interests, funding, institutional congruence, strength of policy and institutional capacity as important. Cultural contextual factors included the influence of policy entrepreneurs, current social trends and public opinion. Exogenous contextual factors included the WHO FCTC, tobacco industry influence at the national-level and bi-lateral partnerships. Further understanding contextual factors affecting the WHO FCTC national implementation can strengthen policy formulation and align required support with the WHO FCTC Secretariat and other relevant bodies.
‘It’ll save your lungs’: early insights into nicotine pouch use and perceptions among young Australians
Authors: Watts Christina , McGill Bronwyn , Rose Shiho , Yazidjoglou Amelia , Chapman Lorena , Dessaix Anita , Freeman Becky
Published: November 2024

Flavoured oral nicotine pouches, manufactured and marketed by global tobacco companies, such as Philip Morris International (PMI) and British American Tobacco, entered the Australian market in 2024. Despite it being illegal for Australian retailers to sell nicotine pouches, the products have been seized in government enforcement raids of Australian retailers, and have also been promoted to young people by Australian social media influencers. The Australian Federal Government has recognized and expressed concern about the rising profile of nicotine pouches in Australia and the promotion of these products as unproven vaping and smoking cessation aids. Yet to date, there has been no published research on nicotine pouches in Australia. Using focus group and interview data collected in early 2024 as part of Generation Vape, an ongoing Australian national study into adolescent and young adult vaping and smoking, we explored their attitudes to and perceptions of nicotine pouches, including first-hand experiences and drivers of use. The participants perceived an increase in the use and popularity of oral nicotine pouches, including PMI’s Zyn brand, for reasons including claimed sport performance enhancement, vaping cessation and as part of partying and clubbing culture. Some participants perceived nicotine pouches to be a ‘healthier’ alternative to smoking or vaping. It is critical that research on nicotine pouches is collected now to inform public health policy and to prevent the proliferation of a new class of addictive recreational nicotine products in Australia.
Tobacco industry narratives of e-cigarette use in the UK: a qualitative framing analysis
Authors: Harrison Ellie , Petticrew Mark , Burns Rose , van Schalkwyk May C I , Hawkins Benjamin
Published: November 2024

Public health actors have expressed concerns over the entry of the tobacco industry into the UK e-cigarette market. It is important to be aware of the tobacco industry’s involvement and stated aims for e-cigarettes in the UK, given their historical attempts to divert attention from and escape responsibility for the harms caused by combustible cigarettes. The use of e-cigarettes amongst young people in the UK has remained constant, despite the law prohibiting sales to adolescents and claims by manufacturers and others that they are designed solely as a tool to quit smoking. This study sought to examine how tobacco-related organizations in the UK e-cigarette market frame the use of e-cigarettes. Publicly available materials between September 2015 and June 2023 were collected from four transnational tobacco companies which have invested in the e-cigarette category, and from a UK e-cigarette trade association. A qualitative framing analysis of materials was conducted guided by relevant frameworks from the Commercial Determinants of Health literature. The analysis identified seven framings used by tobacco-related organizations relevant to e-cigarette usage in the UK. These were: co-opting of harm reduction; consumer choice; following the ‘evidence’; insufficient evidence; the right kind of regulation; ‘us’ and ‘them’ rhetoric and marketing and advertising. By highlighting tobacco-related organizations’ e-cigarette framings and contradictions, this study raises awareness of the rhetorical strategies used by the industry which aim to relegitimize tobacco companies in the political and public spheres.