Historical Geographical Information Systems

Field Guide to Northern Tree-related Microhabitats: Descriptions and size limits for their inventory in boreal and hemiboreal forests of Europe and North America

R. Bütler Sauvain; L. Larrieu; L. F. Lunde; M. Maxence; B. Nordén et al. 

A tree-related microhabitat (abbreviated as TreM) is a morphological feature present on a tree, which is used by sometimes highly specialised species during at least one part of their life cycle. These features may serve as shelters, breeding spots, or crucial hibernation or feeding places for thousands of species. Each TreM provides very specific conditions to the inhabiting species, depending on its characteristics, such as size, shape, position in the tree, degree of decomposition of the surrounding wood, condition of the bearing tree (living or dead), exposure to sunlight, microclimate, and moisture content. The diversity of TreMs in a forest stand directly influences the diversity of species because different TreMs provide optimal conditions for various species to thrive. To reinforce biodiversity in a stand and thus improve its resilience, we need to know which TreMs are present, and to preserve and favour them through adapted management practices. This field guide describes 52 TreMs in boreal and hemiboreal forests. These microhabitats can be categorised into 17 groups, with these groups falling within 7 overarching forms. The guide also indicates recommended minimum inventory sizes for each TreM and gives information about the TreM’s life traits, development rhythm, and associated species. This booklet is specifically tailored to boreal and hemiboreal forests.

Data Champions Lunch Talks – Green Bytes: Data-Driven Approaches to EPFL Sustainability

M. S. P. Cubero-Castan; M. Peon Quiros; C. Gabella; F. Varrato; Loïc Lannelongue 

For this edition of the DC Lunch Talks series, the discussion centered around Data-Driven Approaches to sustainability at EPFL, a topic of significant relevance in the contemporary academic landscape. The event featured a series of short talks by experts who shared their insights and perspectives on the integration of green technologies and hints for research data management and analysis. The speakers and their respective topics are: * “Data and sustainability at a server level”, by Dr. Miguel Peon Quiros, Computer Scientist and administrator of the EPFL EcoCloud; * “Computational work as part of a solution: extracting electricity from heat”, by Enrico Di Lucente, EPFL PhD Student in Materials Science and Engineering, ; * “GREENER principles for environmentally sustainable computational science”, by Dr. Loïc Lannelongue, Specialist in Biomedical data science and research sustainability at Univ. of Cambridge; * “Situation at EPFL and experiences in minimizing our data footprint”, by Dr. Manuel Cubero-Castan, Manager for Sustainable IT Systems Project at EPFL Sustainability. Following the presentations, attendees had the opportunity to engage with the panel in a lively Q&A session, fostering thoughtful conversations on the pivotal role of research data production and storage for tackling the goals of sustainability. The event was held on April 18th, 2024, thanks to the organization of the RDM Team of EPFL Library. You can find here the files of the presentations. You can learn more here about the EPFL Data Champions here, https://go.epfl.ch/datachampions.

Comparison of Three Viral Nucleic Acid Preamplification Pipelines for Sewage Viral Metagenomics

X. Fernandez Cassi; T. Kohn 

Viral metagenomics is a useful tool for detecting multiple human viruses in urban sewage. However, more refined protocols are required for its effective use in disease surveillance. In this study, we investigated the performance of three different preamplification pipelines (specific to RNA viruses, DNA viruses or both) for viral genome sequencing using spiked-in Phosphate Buffered Saline and sewage samples containing known concentrations of viruses. We found that compared to the pipeline targeting all genome types, the RNA pipeline performed better in detecting RNA viruses in both spiked and unspiked sewage samples, allowing the detection of various mammalian viruses including members from the Reoviridae, Picornaviridae, Astroviridae and Caliciviridae. However, the DNA-specific pipeline did not improve the detection of mammalian DNA viruses. We also measured viral recovery by quantitative reverse transcription polymerase chain reaction and assessed the impact of genetic background (non-viral genetic material) on viral coverage. Our results indicate that viral recoveries were generally lower in sewage (average of 11.0%) and higher in Phosphate Buffered Saline (average of 23.4%) for most viruses. Additionally, spiked-in viruses showed lower genome coverage in sewage, demonstrating the negative effect of genetic background on sequencing. Finally, correlation analysis revealed a relationship between virus concentration and genome normalized reads per million, indicating that viral metagenomic sequencing can be semiquantitative.

How to Support Students to Develop Skills that Promote Sustainability

How to Support Students Giving Each Other Constructive Feedback, Especially When It Is Difficult to Hear

How teachers can use the 3T PLAY trident framework to design an activity that develops transversal skills

The conceptual foundations of innate immunity: Taking stock 30 years later

Pradeu Thomas; Thomma Bart T.P.H.; Girarding Stephen; B. Lemaitre 

While largely neglected over decades during which adaptive immunity captured most of the attention, innate immune mechanisms have now become central to our understanding of immunology. Innate immunity provides the first barrier to infection in vertebrates, and it is the sole mechanism of host defense in invertebrates and plants. Innate immunity also plays a critical role in maintaining homeostasis, shaping the microbiota, and in disease contexts such as cancer, neurodegeneration, metabolic syndromes, and aging. The emergence of the field of innate immunity has led to an expanded view of the immune system, which is no longer restricted to vertebrates and instead concerns all metazoans, plants, and even prokaryotes. The study of innate immunity has given rise to new concepts and language. Here, we review the history and definition of the core concepts of innate immunity, discussing their value and fruitfulness in the long run.

Radio-Activities: Architecture and Broadcasting in Cold War Berlin

A. Thiermann 

A historical and theoretical account of the city of Berlin from the intertwined perspectives of architecture, environmental, and media studies. In 1945, having occupied German territory, Soviet troops made two strategic moves: they dismantled the Deutschlandsender III radio transmission tower, the single tallest structure at the time in Europe, and they seized the Haus des Rundfunks in West Berlin, a monumental building designed by Hans Poelzig. These moves were crucial both symbolically and technically, as together they sparked what would become a veritable radio war between the Eastern and Western blocs during the Cold War. In Radio-Activities, Alfredo Thiermann Riesco investigates this spatial conflict as he interrogates the political, technological, and environmental dimensions of architecture at a time when buildings began to interact with the remote transmission of information. By its very nature, the medium of radio promised to evaporate the intrinsic material aspect of architecture; in fact, it did no such thing. By way of transscalar analyses, Thiermann Riesco pays particular attention to Berlin’s buildings, walls, transmission towers, factories, research institutions, and territorial organizations during the Cold War period, which enabled the production, reproduction, and transmission of sonic-based content across the divide of the Iron Curtain. In doing so he reveals underresearched continuities between politics, technology, media, and architecture, in the process reframing notions of national and transnational boundaries. A timely and fascinating study, Radio-Activities brilliantly interrogates the status and agency of buildings during a period-not unlike today’s-of increasingly hyperconnected, ubiquitous, and invisible modes of coexistence.

No Last One

A. Thiermann 

All That is Solid

Characterization of the gut-bone marrow axis through bile acid signaling

Studies of crystal collimation for heavy ion operation at the LHC

Engineering novel protein interactions with therapeutic potential using deep learning-guided surface design

Querying the Digital Archive of Science: Distant Reading, Semantic Modelling and Representation of Knowledge

Hybrid organic/metal-oxide shells on semiconductor nanocrystals via colloidal atomic layer deposition

Electrical and Optical Manifestations of Flat Band Physics in Van der Waals Materials

Plasmonically enhanced molecular junctions for investigation of atomic-scale fluctuations in self-assembled monolayers

Exact Obstacle Avoidance for Robots in Complex and Dynamic Environments Using Local Modulation

S-acylation and lipid exchange at the ER-Golgi membrane contact sites regulate pathogen entry in human cells

Serial Dependence in Human Visual Perception and Decision-Making

Data-Driven Methods for Controller Design in Atomic Force Microscopy

Quantum-mechanical effects in photoluminescence from thin crystalline gold films

A. R. Bowman; A. Rodríguez Echarri; F. Kiani Shahvandi; F. Iyikanat; T. Tsoulos et al. 

Luminescence constitutes a unique source of insight into hot carrier processes in metals, including those in plasmonic nanostructures used for sensing and energy applications. However, being weak in nature, metal luminescence remains poorly understood, its microscopic origin strongly debated, and its potential for unraveling nanoscale carrier dynamics largely unexploited. Here, we reveal quantum-mechanical effects in the luminescence emanating from thin monocrystalline gold flakes. Specifically, we present experimental evidence, supported by first-principles simulations, to demonstrate its photoluminescence origin (i.e., radiative emission from electron/hole recombination) when exciting in the interband regime. Our model allows us to identify changes to the measured gold luminescence due to quantum-mechanical effects as the gold film thickness is reduced. Excitingly, such effects are observable in the luminescence signal from flakes up to 40 nm in thickness, associated with the out-of-plane discreteness of the electronic band structure near the Fermi level. We qualitatively reproduce the observations with first-principles modeling, thus establishing a unified description of luminescence in gold monocrystalline flakes and enabling its widespread application as a probe of carrier dynamics and light-matter interactions in this material. Our study paves the way for future explorations of hot carriers and charge-transfer dynamics in a multitude of material systems.

Quantifying the effects of rainfall temporal variability on landscape evolution processes

T. Lian; N. Peleg; S. Bonetti 

Rainfall characteristics such as intensity, duration, and frequency are key determinants of the hydro-geomorphological response of a catchment. The presence of non-linear and threshold effects makes the relationship between rainfall variability and geomorphological dynamics difficult to quantify. This is particularly relevant under predicted exacerbated erosion induced by an intensification of hydroclimatic extremes. In this study, we quantify the effects of changes in rainfall temporal variability on catchment morphology and sediment erosion, transport, and deposition across a broad spectrum of grain size distributions and climatic conditions. To this purpose, multiple rainfall realizations are simulated using a numerical rainfall generator, while geomorphic response and soil erosion dynamics are assessed through a landscape evolution model (CAESAR-Lisflood). Virtual catchments are used for the numerical experiments and simulations are conducted over centennial time scales. Simulation results show that higher rainfall temporal variability increases net sediment discharge, domain erosion and deposition volumes, and secondary channel development. Particularly, dry regions respond more actively to rainfall variations and finer grain size configurations amplify the hydro-geomorphological response. We find that changes in erosion rates due to rainfall variations can be expressed as a power-law function of the ratio of rainfall temporal variabilities (quantified here through the Gini index). Results are further supported by long-term observational data and simulations over real catchments. Such quantification of the effects of predicted changes in rainfall patterns on catchment hydro-geomorphic response, as mediated by local soil properties, is crucial to forecasting modifications in sediment dynamics due to climate change.

Towards a metabolic theory of catchments: scaling of water and carbon fluxes with size

F. Bassani; S. Fatichi; S. Bonetti 

Allometric scaling relations are widely used to link biological processes in nature. They are typically expressed as power laws, postulating that the metabolic rate of an organism scales as its mass to the power of an allometric exponent, which ranges between 2/3 and 3/4. Several studies have shown that such scaling laws hold also for natural ecosystems, including individual trees and forests, riverine metabolism, and river network organization. Here, we focus on allometric relations at watershed scale to investigate “catchment metabolism”, defined as the set of ecohydrological and biogeochemical processes through which the catchment maintains its structure and reacts to the environment. By revising existing plant size-density relationships and integrating them across large-scale domains, we show that the ecohydrological fluxes (representative of metabolic rates of a large and diverse vegetation assemblage) occurring at the catchment scale are invariant with respect to its average above-ground biomass, while they scale linearly with the basin size. We verify our theory with hyper-resolution ecohydrological simulations across the European Alps, which represent an ideal case study due to the large elevation gradient affecting the availability of energy and water resources. Deviations from the isometric scaling are observed and ascribable to energy limitations at high elevations. Remote sensing data from semiarid and tropical basins are also used to show that the observed scaling of water and carbon fluxes with size holds across a broad spectrum of climatic conditions.

Biohybrid Superorganisms—On the Design of a Robotic System for Thermal Interactions With Honeybee Colonies

R. Barmak; D. N. Hofstadler; M. Stefanec; L. Piotet; R. Cherfan et al. 

Social insects, such as ants, termites, and honeybees, have evolved sophisticated societies where collaboration and division of labor enhance survival of the whole colony, and are thus considered “superorganisms”. Historically, studying behaviors involving large groups under natural conditions posed significant challenges, often leading to experiments with a limited number of organisms under artificial laboratory conditions that incompletely reflected the animals’ natural habitat. A promising approach to exploring animal behaviors, beyond observation, is using robotics that produce stimuli to interact with the animals. However, their application has predominantly been constrained to small groups in laboratory conditions. Here we present the design choices and development of a biocompatible robotic system intended to integrate with complete honeybee colonies in the field, enabling exploration of their collective thermoregulatory behaviors via arrays of thermal sensors and actuators. We tested the system’s ability to capture the spatiotemporal signatures of two key collective behaviors. A 121-day observation revealed thermoregulation activity of the broodnest area during the foraging season, followed by clustering behavior during winter. Then we demonstrated the system’s ability to influence the colony by guiding a cluster of bees along an unnatural trajectory, via localized thermal stimuli emitted by two robotic frames. These results showcase a system with the capability to experimentally modulate honeybee colonies from within, as well as to unobtrusively observe their dynamics over extended periods. Such biohybrid systems uniting complete societies of thousands of animals and interactive robots can be used to confirm or challenge the existing understanding of complex animal collectives.

Dataset to accompany publication “Quantum-mechanical effects in photoluminescence from thin crystalline gold films”

A. R. Bowman; Á. Rodríguez Echarri; F. Kiani Shahvandi; F. Iyikanat; T. Tsoulos et al. 

This dataset accompanies the publication “Quantum-mechanical effects in photoluminescence from thin crystalline gold films” published in Light: Science & Applications (https://doi.org/10.1038/s41377-024-01408-2). The data can be used to reproduce plots 1-4 in the main text and all plots with data in the supporting information. This data was generated through a combination of raman spectroscopy, microscale absorption meaurements and density functional theory modelling. All files are in excel spreadsheets and easily readable, except compressed files which have a readme file in the appropriate section. The abstract for the associated paper is as follows: Luminescence constitutes a unique source of insight into hot carrier processes in metals, including those in plasmonic nanostructures used for sensing and energy applications. However, being weak in nature, metal luminescence remains poorly understood, its microscopic origin strongly debated, and its potential for unravelling nanoscale carrier dynamics largely unexploited. Here, we reveal quantum-mechanical effects emanating in the luminescence from thin monocrystalline gold flakes. Specifically, we present experimental evidence, supported by first-principles simulations, to demonstrate its photoluminescence origin (i.e., radiative emission from electron/hole recombination) when exciting in the interband regime. Our model allows us to identify changes to the measured gold luminescence due to quantum-mechanical effects as the gold film thickness is reduced. Excitingly, such effects are observable in the luminescence signal from flakes up to 40 nm in thickness, associated with the out-of-plane discreteness of the electronic band structure near the Fermi level. We qualitatively reproduce the observations with first-principles modelling, thus establishing a unified description of luminescence in gold monocrystalline flakes and enabling its widespread application as a probe of carrier dynamics and light-matter interactions in this material. Our study paves the way for future explorations of hot carriers and charge-transfer dynamics in a multitude of material systems. 

Impact of CO2-rich seawater injection on the flow properties of basalts

E. Stavropoulou; C. Griner; L. Laloui 

Permanent CO storage in basalts through mineralisation offers a promising solution for reducing carbon emissions and mitigating climate change. This study focuses on the impact of potential mineralisation on the flow properties of the basaltic material. Fluid flow evolution before and after exposure to CO dissolved in seawater is measured in terms of hydraulic conductivity and permeability under field-like conditions over 1 to 3.5 months. Permeability reduction of up to one order of magnitude suggests that porosity decreases due to mineral precipitation after CO exposure. X-ray tomography measurements of the tested cores reveal a maximum porosity decrease of 1.5% at the given resolution (50 μm/px). To better understand eventual modifications of the connected pore network after mineralisation, fluid flow simulations are performed on the 3D pore network of the material that is reconstructed directly from the acquired x-ray images. A double porosity is proposed: macro-porosity as visible from the tomographies (pores >50 μm) and micro-porosity (pores <50 μm). To reproduce the post-CO exposure flow, reduction of macro-porosity is not enough. Instead, a decrease of the micro-pores is necessary by up to 43%. The experimental and numerical results suggest that potential mineralisation can substantially modify the pore space of the intact basaltic material and consequently impact storage efficiency if flow is not preserved.

Architecture of a decentralised decision support system for futuristic beehives

V. Komasilovs; R. Mills; A. Kviesis; F. Mondada; A. Zacepins 

Honeybees are essential to human society, providing pollination services globally as well as producing honey and other valuable products. Effective management of apiaries should not only rely on beekeeper knowledge and skill, but also incorporate new information technologies. The options to identify, predict and prevent beekeeping problems are becoming more affordable and applicable. The interdisciplinary Horizon 2020 project HIVEOPOLIS focuses on developing a new approach in beekeeping, by creating novel mechatronic beehives and implementing new bio-hybrid ideas. These intelligent beehives aim to help honeybees to cope with adverse environmental factors and increase the survival rate of the bee colonies. This paper focuses on the software architecture design for these intelligent beehives, providing infrastructure for data management and decision support system operation. The presented infrastructure is suitable for highly dynamic and diverse environments where a multitude of components interact and exchange information across technology domains (embedded, cloud, UIs) in a reliable and secure way. Besides user support, the decision support system built upon this infrastructure enables closed-loop automated decision making and control.

TSLAM: a tag-based object-centered monocular navigation system for augmented manual woodworking.

S. Andrea; H-B. Yang; G. Julien; W. Yves 

TimberSLAM (TSLAM) is an object-centered, tag-based visual self-localization and mapping (SLAM) system for monocular RGB cameras. It was specifically developed to support a robust and augmented reality pipeline for close-range, noisy, and cluttered fabrication sequences that involve woodworking operations, such as cutting, drilling, sawing, and screwing with multiple tools and end-effectors. By leveraging and combining multiple open-source projects, we obtain a functional pipeline that can map, three-dimensionally reconstruct, and finally provide a robust camera pose stream during fabrication time to overlay an execution model with its digital-twin model, even under close-range views, dynamic environments, and heavy scene obstructions. To benchmark the proposed navigation system under real fabrication scenarios, we produce a data set of 1344 closeups of different woodworking operations with multiple tools, tool heads, and varying parameters (e.g., tag layout and density). The evaluation campaign indicates that TSLAM is satisfyingly capable of detecting the camera’s millimeter position and subangular rotation during the majority of fabrication sequences. The reconstruction algorithm’s accuracy is also gauged and yields results that demonstrate its capacity to acquire shapes of timber beams with up to two preexisting joints. We have made the entire source code, evaluation pipeline, and data set open to the public for reproducibility and the benefit of the community.

Water weakening and the compressive brittle strength of carbonates: Influence of fracture toughness and static friction

C. Noël; B. Fryer; P. Baud; M. Violay 

Water is ubiquitous within the pore space of rocks and has been shown to affect their physical and mechanical behaviour. Indeed, water can act on the rock strength via mechanical (i.e., reducing the effective stresses) or chemical effects (e.g., mineral dissolution, mineral alteration, subcritical crack growth, etc.). As rock macroscopic strength is controlled by both fracture toughness and friction at the grain-scale, these parameters should also be affected in presence of water. While some recent studies have measured the effect of water on both fracture toughness and frictional parameters to constrain the water weakening of porous rock compressive strength, the physical parameters, or rock characteristics, that influence this weakening are as of yet unclear. Here, we report a series of laboratory experiments in order to determine the influence of a water-saturated, as opposed to dry, environment on five limestones’ strengths. The uniaxial compressive strength, the mode-I fracture toughness and the static friction parameters are of interest. The experiments show that, for the tested limestones, water-saturated conditions provoke a reduction of the uniaxial compressive strength by up to 53 %. This reduction is accompanied by a reduction of the mode-I fracture toughness by up to 34 % and of the static friction by up to 16 %. Even though the water weakening of the uniaxial compressive strength is not influenced by the sample porosity, the mode-I fracture toughness reduction in the presence of water is accentuated for high-porosity limestones. Additionally, low porosity limestones appear to promote higher static friction reductions in water-saturated environments.

Integration of the Pilatus3 detector for soft X-ray diagnostics on TCV

S. Masillo 

Siloxide tripodal ligands as a scaffold for stabilizing lanthanides in the +4 oxidation state

M. C. G. Tricoire; F-C. Hsueh; M. R. Keener; T. Rajeshkumar; R. Scopelliti et al. 

Synthetic strategies to isolate molecular complexes of lanthanides, other than cerium, in the +4 oxidation state remain elusive, with only four complexes of Tb(iv) isolated so far. Herein, we present a new approach for the stabilization of Tb(iv) using a siloxide tripodal trianionic ligand, which allows the control of unwanted ligand rearrangements, while tuning the Ln(iii)/Ln(iv) redox-couple. The Ln(iii) complexes, [LnIII((OSiPh2Ar)3-arene)(THF)3] (1-LnPh) and [K(toluene){LnIII((OSiPh2Ar)3-arene)(OSiPh3)}] (2-LnPh) (Ln = Ce, Tb, Pr), of the (HOSiPh2Ar)3-arene ligand were prepared. The redox properties of these complexes were compared to those of the Ln(iii) analogue complexes, [LnIII((OSi(OtBu)2Ar)3-arene)(THF)] (1-LnOtBu) and [K(THF)6][LnIII((OSi(OtBu)2Ar)3-arene)(OSiPh3)] (2-LnOtBu) (Ln = Ce, Tb), of the less electron-donating siloxide trianionic ligand, (HOSi(OtBu)2Ar)3-arene. The cyclic voltammetry studies showed a cathodic shift in the oxidation potential for the cerium and terbium complexes of the more electron-donating phenyl substituted scaffold (1-LnPh) compared to those of the tert-butoxy (1-LnOtBu) ligand. Furthermore, the addition of the -OSiPh3 ligand further shifts the potential cathodically, making the Ln(iv) ion even more accessible. Notably, the Ce(iv) complexes, [CeIV((OSi(OtBu)2Ar)3-arene)(OSiPh3)] (3-CeOtBu) and [CeIV((OSiPh2Ar)3-arene)(OSiPh3)(THF)2] (3-CePh), were prepared by chemical oxidation of the Ce(iii) analogues. Chemical oxidation of the Tb(iii) and Pr(iii) complexes (2-LnPh) was also possible, in which the Tb(iv) complex, [TbIV((OSiPh2Ar)3-arene)(OSiPh3)(MeCN)2] (3-TbPh), was isolated and crystallographically characterized, yielding the first example of a Tb(iv) supported by a polydentate ligand. The versatility and robustness of these siloxide arene-anchored platforms will allow further development in the isolation of more oxidizing Ln(iv) ions, widening the breadth of high-valent Ln chemistry.|Robust arene-anchored polydentate siloxide ligands allow to control unwanted ligand rearrangements for the isolation of Tb(iv) complexes thus enabling the use of the Tb(iii)/Tb(iv) couple for the separation of Tb from the neighboring Dy ion.

High-Permittivity Polysiloxanes for Bright, Stretchable Electroluminescent Devices

J. von Szczepanski; J. Wolf; W-H. Hu; R. Schneider; P. M. Danner et al. 

Stretchable alternating current electroluminescent (ACEL) devices have a bright future in wearable electronics and soft robotics. Still, their market application is hindered by high operating voltages. The voltage can be reduced by increasing the relative permittivity of the dielectric elastomer in the emissive layer. Here, a fluorine-free high-permittivity silicone elastomer functionalized with cyanopropyl side groups, specially designed for application in stretchable ACEL devices, is introduced. The polar silicone elastomer exhibits excellent mechanical properties and a dielectric permittivity four times higher than commercial PDMS. Light-emitting devices based on the polar elastomer reach 7.5 times higher maximum luminance at the same electric field than PDMS-based devices and turn on at a 50% lower electric field. Besides, the polar elastomer-based devices perform better than all materials tested in literature in achieving high luminance at low electric fields. Stretchable ACEL devices are built from the polar elastomer which shows bright and uniform light emission and can be operated up to 50% strain. The high-permittivity silicones are promising materials for stretchable ACEL devices and can help their breakthrough to market application by overcoming the drawback of high operating voltages.|A high-permittivity, nitrile-functional silicone elastomer for application in stretchable electroluminescent devices is introduced. The polar elastomer emissive layer reaches significantly higher luminance and needs lower operating voltages than an emissive layer based on commercially available PDMS. Besides, the polar elastomer can be used to build bright and stretchable devices in a simple bottom-up procedure. image

An extension of the stochastic sewing lemma and applications to fractional stochastic calculus

T. Matsuda; N. Perkowski 

We give an extension of Le’s stochastic sewing lemma. The stochastic sewing lemma proves convergence in $L_m$ of Riemann type sums $\sum _{[s,t] \in \pi } A_{s,t}$ for an adapted two-parameter stochastic process A, under certain conditions on the moments of $A_{s,t}$ and of conditional expectations of $A_{s,t}$ given $\mathcal F_s$ . Our extension replaces the conditional expectation given $\mathcal F_s$ by that given $\mathcal F_v$ for $v

Forum Of Mathematics Sigma

2024-04-11

DOI : 10.1017/fms.2024.32

A bridge between trust and control: computational workflows meet automated battery cycling

P. Kraus; E. Bainglass; F. F. Ramirez; E. Svaluto-Ferro; L. Ercole et al. 

Compliance with good research data management practices means trust in the integrity of the data, and it is achievable by full control of the data gathering process. In this work, we demonstrate tooling which bridges these two aspects, and illustrate its use in a case study of automated battery cycling. We successfully interface off-the-shelf battery cycling hardware with the computational workflow management software AiiDA, allowing us to control experiments, while ensuring trust in the data by tracking its provenance. We design user interfaces compatible with this tooling, which span the inventory, experiment design, and result analysis stages. Other features, including monitoring of workflows and import of externally generated and legacy data are also implemented. Finally, the full software stack required for this work is made available in a set of open-source packages.

Capsizing due to friction-induced twist in the failure of stopper knots

P. Johanns; P. M. Reis 

We investigate the failure mechanism of stopper knots, with a particular focus on the figure -8 knot as a representative example. Stopper knots are widely used in climbing, sailing, racket stringing, and sewing to maintain tension in ropes, strings, or threads while preventing them from passing through an orifice. Combining high -precision model experiments and Finite Element Analyses, we systematically explore the influence of frictional interactions and their role in the build-up of mechanical twist. Our findings reveal that the failure of stopper knots via capsizing, which involves configurational alterations of the filament, is primarily due to friction -induced twisting when loading the knot against a restraining plate containing a clearance hole. Our study offers a comprehensive understanding of the mechanical behavior of stopper knots under diverse loading conditions, thereby providing crucial insights for their reliable application across various domains.

A CTCF-dependent mechanism underlies the Hox timer relation to a segmented body plan

H. Rekaik; D. Duboule 

During gastrulation, Hox genes are activated in a timesequence that follows the order of the genes along their clusters. This property, which is observed in all animals that develop following a progressive rostral-to-caudal morphogenesis, is associated with changes in the chromatin structure and epigenetic profiles of Hox clusters, suggesting a process at least partly based on sequential gene accessibility. Here, we discuss recent work on this issue, as well as a possible mechanism based on the surprising conservation in both the distribution and orientation of CTCF sites inside vertebrate Hox clusters.

Gradient High-Q Dielectric Metasurfaces for Broadband Sensing and Control of Vibrational Light-Matter Coupling

F. U. Richter; I. Sinev; S. Zhou; A. Leitis; S-H. Oh et al. 

Surface-enhanced infrared absorption spectroscopy (SEIRA) has emerged as a powerful technique for ultrasensitive chemical-specific analysis. SEIRA can be realized by employing metasurfaces that can enhance light-matter interactions in the spectral bands of molecular vibrations. Increasing sample complexity emphasizes the need for metasurfaces that can operate simultaneously at different spectral bands, both accessing rich spectral information over a broad band, and resolving subtle differences in the absorption fingerprints through narrow-band resonances. Here, a novel concept of resonance-gradient metasurfaces is introduced, where the required spectral selectivity is achieved via local high-quality-factor (high-Q) resonances, while the continuous coverage of a broad band is enabled by the gradual adjustment of the unit-cell dimensions along the planar structure. The highly tailorable design of the gradient metasurfaces provides flexibility for shaping the spectral sampling density to match the relevant bands of target analytes while keeping a compact device footprint. The versatility of the gradient metasurfaces is demonstrated through several sensing scenarios, including polymer mixture deconvolution, detecting a multistep bioassay, and identification of the onset of vibrational strong coupling regime. The proposed gradient-resonance platform significantly contributes to the rapidly evolving landscape of nonlocal metasurfaces, enabling applications in molecular detection and analysis of fundamental light-matter interaction phenomena.

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

J. A. Borrel; J. Waser 

We report the detailed background for the discovery and development of the synthesis of homopropargylic azides by the azidoalkynylation of alkenes. Initially, a strategy involving SOMOphilic alkynes was adopted, but only resulted in a 29% yield of the desired product. By switching to a radical-polar crossover approach and after optimization, a high yield (72%) of the homopropargylic azide was reached. Full insights are given about the factors that were essential for the success of the optimization process.

Dielectric elastomer actuator-based valveless pump as Fontan failure assist device: introduction and preliminary study

A. Benouhiba; A. M. Walter; S. E. Jahren; T. G. Martinez; F. Clavica et al. 

OBJECTIVES: Fontan failure refers to a condition in which the Fontan circulation, a surgical procedure used to treat certain congenital heart defects, becomes insufficient, leading to compromised cardiac function and potential complications. This in vitro study therefore investigates the feasibility of bladeless impedance-driven cavopulmonary assist device via dielectric elastomer actuator (DEA) as a means to address Fontan failure. METHODS: A cavopulmonary assist device, constructed using DEA technologies and employing the impedance pump concept, is subjected to in vitro testing within a closed-loop setup. This study aims to assess the device’s functionality and performance under controlled conditions, providing valuable insights into its potential application as a cavopulmonary assistive technology. RESULTS: The DEA-based pump, measuring 50 mm in length and 30 mm in diameter, is capable of achieving substantial flow rates within a closed-loop setup, reaching up to 1.20 l/min at an activation frequency of 4 Hz. It also provides a broad range of working internal pressures (<10 to >20 mmHg). Lastly, the properties of the flow (direction, magnitude, etc.) can be controlled by adjusting the input signal parameters (frequency, amplitude, etc.). CONCLUSIONS: In summary, the results suggest that the valveless impedance-driven pump utilizing DEA technology is promising in the context of cavopulmonary assist devices. Further research and development in this area may lead to innovative and potentially more effective solutions for assisting the right heart, ultimately benefiting patients with heart-related health issues overall, with a particular focus on those experiencing Fontan failure.

Tree diversity reduces variability in sapling survival under drought

H. Blondeel; J. Guillemot; N. Martin-StPaul; A. Druel; S. Bilodeau-Gauthier et al. 

Enhancing tree diversity may be important to fostering resilience to drought-related climate extremes. So far, little attention has been given to whether tree diversity can increase the survival of trees and reduce its variability in young forest plantations. We conducted an analysis of seedling and sapling survival from 34 globally distributed tree diversity experiments (363,167 trees, 168 species, 3744 plots, 7 biomes) to answer two questions: (1) Do drought and tree diversity alter the mean and variability in plot-level tree survival, with higher and less variable survival as diversity increases? and (2) Do species that survive poorly in monocultures survive better in mixtures and do specific functional traits explain monoculture survival? Tree species richness reduced variability in plot-level survival, while functional diversity (Rao’s Q entropy) increased survival and also reduced its variability. Importantly, the reduction in survival variability became stronger as drought severity increased. We found that species with low survival in monocultures survived comparatively better in mixtures when under drought. Species survival in monoculture was positively associated with drought resistance (indicated by hydraulic traits such as turgor loss point), plant height and conservative resource-acquisition traits (e.g. low leaf nitrogen concentration and small leaf size). Synthesis. The findings highlight: (1) The effectiveness of tree diversity for decreasing the variability in seedling and sapling survival under drought; and (2) the importance of drought resistance and associated traits to explain altered tree species survival in response to tree diversity and drought. From an ecological perspective, we recommend mixing be considered to stabilize tree survival, particularly when functionally diverse forests with drought-resistant species also promote high survival of drought-sensitive species.|Rising climate extremes, such as drought, can cause major uncertainty in the survival of young trees. Tree diversity can reduce survival variability and stabilize tree survival. Functionally diverse communities with drought-tolerant species can promote the survival of drought-sensitive species.image

Probing structural and dynamic properties of MAPbCl3 hybrid perovskite using Mn2+ EPR

G. Usevicius; J. Turcak; Y. Zhang; A. Eggeling; Z. Einoryte et al. 

Hybrid methylammonium (MA) lead halide perovskites have emerged as materials exhibiting excellent photovoltaic performance related to their rich structural and dynamic properties. Here, we use multifrequency (X-, Q-, and W-band) electron paramagnetic resonance (EPR) spectroscopy of Mn2+ impurities in MAPbCl(3) to probe the structural and dynamic properties of both the organic and inorganic sublattices of this compound. The temperature dependent continuous-wave (CW) EPR experiments reveal a sudden change of the Mn2+ spin Hamiltonian parameters at the phase transition to the ordered orthorhombic phase indicating its first-order character and significant slowing down of the MA cation reorientation. Pulsed EPR experiments are employed to measure the temperature dependences of the spin-lattice relaxation T-1 and decoherence T-2 times of the Mn2+ ions in the orthorhombic phase of MAPbCl(3) revealing a coupling between the spin center and vibrations of the inorganic framework. Low-temperature electron spin echo envelope modulation (ESEEM) experiments of the protonated and deuterated MAPbCl(3) analogues show the presence of quantum rotational tunneling of the ammonium groups, allowing to accurately probe their rotational energy landscape.

Dalton Transactions

2024-04-03

DOI : 10.1039/d4dt00116h

Benchmarking machine-readable vectors of chemical reactions on computed activation barriers

P. E. Van Gerwen; K. R. Briling; Y. Calvino Alonso; M. Franke; C. Corminboeuf 

In recent years, there has been a surge of interest in predicting computed activation barriers, to enable the acceleration of the automated exploration of reaction networks. Consequently, various predictive approaches have emerged, ranging from graph-based models to methods based on the three-dimensional structure of reactants and products. In tandem, many representations have been developed to predict experimental targets, which may hold promise for barrier prediction as well. Here, we bring together all of these efforts and benchmark various methods (Morgan fingerprints, the DRFP, the CGR representation-based Chemprop, SLATMd, B2Rl2, EquiReact and language model BERT + RXNFP) for the prediction of computed activation barriers on three diverse datasets.|We benchmark various methods for the prediction of computed activation barriers on three diverse datasets.

Quantum radio astronomy: Data encodings and quantum image processing

T. Brunet; E. E. Tolley; S. Corda; R. Ilic; P. C. Broekema et al. 

We explore applications of quantum computing for radio interferometry and astronomy using recent developments in quantum image processing. We evaluate the suitability of different quantum image representations using a toy quantum computing image reconstruction pipeline, and compare its performance to the classical computing counterpart. For identifying and locating bright radio sources, quantum computing can offer an exponential speedup over classical algorithms, even when accounting for data encoding cost and repeated circuit evaluations. We also propose a novel variational quantum computing algorithm for self -calibration of interferometer visibilities, and discuss future developments and research that would be necessary to make quantum computing for radio astronomy a reality.

Comprehensive Memory Safety Validation: An Alternative Approach to Memory Safety

K. Huang; M. Payer; Z. Qian; J. Sampson; G. Tan et al. 

Comprehensive memory safety validation identifies the memory objects whose accesses provably comply with all classes of memory safety, protecting them from memory errors elsewhere at low overhead. We assess the breadth and depth of comprehensive memory safety validation.

A Method of Moments Estimator for Interacting Particle Systems and their Mean Field Limit

G. A. Pavliotis; A. Zanoni 

We study the problem of learning unknown parameters in stochastic interacting particle systems with polynomial drift, interaction, and diffusion functions from the path of one single particle in the system. Our estimator is obtained by solving a linear system which is constructed by imposing appropriate conditions on the moments of the invariant distribution of the mean field limit and on the quadratic variation of the process. Our approach is easy to implement as it only requires the approximation of the moments via the ergodic theorem and the solution of a low-dimensional linear system. Moreover, we prove that our estimator is asymptotically unbiased in the limits of infinite data and infinite number of particles (mean field limit). In addition, we present several numerical experiments that validate the theoretical analysis and show the effectiveness of our methodology to accurately infer parameters in systems of interacting particles.

A setup for hard x-ray time-resolved resonant inelastic x-ray scattering at SwissFEL

H-Y. Chen; R. B. Versteeg; R. Mankowsky; M. Puppin; L. M. Diniz Leroy et al. 

We present a new setup for resonant inelastic hard x-ray scattering at the Bernina beamline of SwissFEL with energy, momentum, and temporal resolution. The compact R = 0.5 m Johann-type spectrometer can be equipped with up to three crystal analyzers and allows efficient collection of RIXS spectra. Optical pumping for time-resolved studies can be realized with a broad span of optical wavelengths. We demonstrate the performance of the setup at an overall similar to 180 meV resolution in a study of ground-state and photoexcited (at 400 nm) honeycomb 5d iridate alpha-Li2IrO3. Steady-state RIXS spectra at the iridium L-3-edge (11.214 keV) have been collected and are in very good agreement with data collected at synchrotrons. The time-resolved RIXS transients exhibit changes in the energy loss region <2 eV, whose features mostly result from the hopping nature of 5d electrons in the honeycomb lattice. These changes are ascribed to modulations of the Ir-to-Ir inter-site transition scattering efficiency, which we associate to a transient screening of the on-site Coulomb interaction. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)

An aircraft assembly process formalism and verification method based on semantic modeling and MBSE

X. Zheng; X. Hu; J. Lu; R. Arista; J. Lentes et al. 

The aircraft assembly system is highly complex involving different stakeholders from multiple domains. The design of such a system requires comprehensive consideration of various industrial scenarios aiming to optimize key performance indicators. Traditional design methods heavily rely on domain expert knowledge using documents to define assembly solutions which are later verified through simulations. However, these document -centric approaches cannot provide graphical notations for engineers to efficiently understand the entire assembly process. Moreover, it is difficult to analyze the performance of the designed assembly processes using simulations since the simulation models have to be developed based on the documents manually rather than be generated automatically from the design models. In this paper, a semantic -driven approach is proposed to support aircraft assembly process formalism and performance analysis. First, meta -models of aircraft assembly processes are developed based on SysML and discrete -event simulation models using a semantic modeling language named KARMA. Then an application ontology is defined for generating semantic models from KARMA architecture models to capture domain knowledge, system requirements and simulation model information of the aircraft assembly process. A model transformer is developed to transform the KARMA models to discrete -event simulation models based on the application ontology. Then the generated simulation models are executed to obtain the simulation results for verifying the designed assembly process. Finally, the obtained simulation results are used to support decision -making of selecting the optimal aircraft assembly process. A case study is conducted to verify the proposed method.

Stellar Metallicities and Gradients in the Isolated, Quenched Low-mass Galaxy Tucana

S. W. Fu; D. R. Weisz; E. Starkenburg; N. Martin; F. J. Mercado et al. 

We measure the metallicities of 374 red giant branch (RGB) stars in the isolated, quenched dwarf galaxy Tucana using Hubble Space Telescope (HST) narrow-band (F395N) Calcium H & K (CaHK) imaging. Our sample is a factor of similar to 7 similar to 7 larger than what is published. Our main findings are: (i) A global metallicity distribution function (MDF) with <[Fe/H]>=-1.55(-0.04)(+0.04) and( sigma)[Fe/H]= =0.54(-0.03)(+)(0.03) (ii) A metallicity gradient of -0.54 +/- 0.07-0.54 +/- 0.07 dex R-e(-1) (-2.1 +/- 0.3- dex kpc(-1)) over the extent of our imaging (similar to 2.5R(e)), which is steeper than literature measurements. Our finding is consistent with predicted gradients from the publicly-available FIRE-2 simulations, in which bursty star formation creates stellar population gradients and dark matter cores; (iii) Tucana’s bifurcated RGB has distinct metallicities: a blue RGB with <[Fe/H]>=-1.78(-0.06)(+0.06)<[Fe/H]>=-1.78(-0.06)(+0.06) and sigma([Fe/H])=0.44(-0.06)(+0.07 )and a red RGB with <[Fe/H]> = -1.08(-0.07)(+0.07 and alpha)[Fe/H] 0.42 +/- 0.06(iv) At fixed stellar mass, Tucana is more MR than MW satellites by similar to 0.4, but its blue RGB is chemically comparable to the satellites. Tucana’s MDF appears consistent with star-forming isolated dwarfs, though MDFs of the latter are not as well-populated; (v) similar to 2 similar to 2% of Tucana’s stars have [Fe/H]<-3[Fe/H]<-3 and 20% [Fe/H]>-1[Fe/H]>-1. We provide a catalog for community spectroscopic follow-up.

Twisted pair transmission line coil – a flexible, self-decoupled and robust element for 7 T MRI

J. Vliem; Y. Xiao; D. Wenz; L. Xin; W. Teeuwise et al. 

Objective: This study evaluates the performance of a twisted pair transmission line coil as a transceive element for 7 T MRI in terms of physical flexibility, robustness to shape deformations, and interelement decoupling. Methods: Each coil element was created by shaping a twisted pair of wires into a circle. One wire was interrupted at the top, while the other was interrupted at the bottom, and connected to the matching circuit. Electromagnetic simulations were conducted to determine the optimal number of twists per length (in terms of B,+ field efficiency, SAR efficiency, sensitivity to elongation, and interelement decoupling properties) and for investigating the fundamental operational principle of the coil through fields streamline visualisation. A comparison between the twisted pair coil and a conventional loop coil in terms of B,+ fields, maxSAR,0g, and stability of S,, when the coil was deformed was performed. Experimentally measured interelement coupling between individual elements of multichannel arrays was also investigated. Results: Increasing the number of twists per length resulted in a more physically robust coil. Poynting vector streamline visualisation showed that the twisted pair coil concentrated most of the energy in the near field. The twisted pair coil exhibited comparable B,+ fields and improved maxSAR,0g to the conventional coil but demonstrated exceptional stability with respect to coil deformation and a strong self-decoupling nature when placed in an array configuration. Discussion: The findings highlight the robustness of the twisted pair coil, showcasing its stability under shape variations. This coil holds great potential as a flexible RF coil for various imaging applications using multipleelement arrays, benefiting from its inherent decoupling.

3D Printing of Double Network Granular Elastomers with Locally Varying Mechanical Properties

E. J. Baur; B. Tiberghien; E. Amstad 

Fast advances in the design of soft actuators and robots demand for new soft materials whose mechanical properties can be changed over short length scales. Elastomers can be formulated as highly stretchable or rather stiff materials and hence, are attractive for these applications. They are most frequently cast such that their composition cannot be changed over short length scales. A method that allows to locally change the composition of elastomers on hundreds of micrometer lengths scales is direct ink writing (DIW). Unfortunately, in the absence of rheomodifiers, most elastomer precursors cannot be printed through DIW. Here, 3D printable double network granular elastomers (DNGEs) whose ultimate tensile strain and stiffness can be varied over an unprecedented range are introduced. The 3D printability of these materials is leveraged to produce an elastomer finger containing rigid bones that are surrounded by a soft skin. Similarly, the rheological properties of the microparticle-based precursors are leveraged to cast elastomer slabs with locally varying stiffnesses that deform and twist in a predefined fashion. These DNGEs are foreseen to open up new avenues in the design of the next generation of smart wearables, strain sensors, prosthesis, soft actuators, and robots.|A novel ink composed of jammed precursor-loaded elastomeric microparticles that can be direct ink written into double network granular elastomers that can attain a wide range of stiffnesses and ultimate tensile strains is presented. Inks with different stiffnesses can be 3D printed into cm-sized structures with locally varying compositions and hence mechanical properties using commercial multinozzle 3D printers. image

Dopant-additive synergism enhances perovskite solar modules

B. Ding; Y. Ding; J. Peng; J. Romano-deGea; L. E. K. Frederiksen et al. 

Perovskite solar cells (PSCs) are among the most promising photovoltaic technologies owing to their exceptional optoelectronic properties 1,2 . However, the lower efficiency, poor stability and reproducibility issues of large-area PSCs compared with laboratory-scale PSCs are notable drawbacks that hinder their commercialization 3 . Here we report a synergistic dopant-additive combination strategy using methylammonium chloride (MACl) as the dopant and a Lewis-basic ionic-liquid additive, 1,3-bis(cyanomethyl)imidazolium chloride ([Bcmim]Cl). This strategy effectively inhibits the degradation of the perovskite precursor solution (PPS), suppresses the aggregation of MACl and results in phase-homogeneous and stable perovskite films with high crystallinity and fewer defects. This approach enabled the fabrication of perovskite solar modules (PSMs) that achieved a certified efficiency of 23.30% and ultimately stabilized at 22.97% over a 27.22-cm2 aperture area, marking the highest certified PSM performance. Furthermore, the PSMs showed long-term operational stability, maintaining 94.66% of the initial efficiency after 1,000 h under continuous one-sun illumination at room temperature. The interaction between [Bcmim]Cl and MACl was extensively studied to unravel the mechanism leading to an enhancement of device properties. Our approach holds substantial promise for bridging the benchtop-to-rooftop gap and advancing the production and commercialization of large-area perovskite photovoltaics.|A synergistic dopant-additive combination strategy using methylammonium chloride as the dopant and a Lewis-basic ionic-liquid additive is shown to enable the fabrication of perovskite solar modules achieving record certified performance and long-term operational stability.

Proliferation-driven mechanical compression induces signalling centre formation during mammalian organ development

N. P. Shroff; P. Xu; S. Kim; E. R. Shelton; B. J. Gross et al. 

Localized sources of morphogens, called signalling centres, play a fundamental role in coordinating tissue growth and cell fate specification during organogenesis. However, how these signalling centres are established in tissues during embryonic development is still unclear. Here we show that the main signalling centre orchestrating development of rodent incisors, the enamel knot (EK), is specified by a cell proliferation-driven buildup in compressive stresses (mechanical pressure) in the tissue. Direct mechanical measurements indicate that the stresses generated by cell proliferation are resisted by the surrounding tissue, creating a circular pattern of mechanical anisotropy with a region of high compressive stress at its centre that becomes the EK. Pharmacological inhibition of proliferation reduces stresses and suppresses EK formation, and application of external pressure in proliferation-inhibited conditions rescues the formation of the EK. Mechanical information is relayed intracellularly through YAP protein localization, which is cytoplasmic in the region of compressive stress that establishes the EK and nuclear in the stretched anisotropic cells that resist the pressure buildup around the EK. Together, our data identify a new role for proliferation-driven mechanical compression in the specification of a model signalling centre during mammalian organ development.|Shroff and colleagues report that cell proliferation induces localized mechanical compression in the tissue, driving the formation of the main mouse tooth signalling centre via differential YAP expression.

Spin-Reorientation-Driven Linear Magnetoelectric Effect in Topological Antiferromagnet Cu3TeO6

V. Kisicek; D. Dominko; M. Culo; Z. Rapljenovic; M. Kuvezdic et al. 

The search for new materials for energy -efficient electronic devices has gained unprecedented importance. Among the various classes of magnetic materials driving this search are antiferromagnets, magnetoelectrics, and systems with topological spin excitations. Cu3TeO6 is a material that belongs to all three of these classes. Combining static electric polarization and magnetic torque measurements with phenomenological simulations we demonstrate that magnetic -field -induced spin reorientation needs to be taken into account to understand the linear magnetoelectric effect in Cu3TeO6. Our calculations reveal that the magnetic field pushes the system from the nonpolar ground state to the polar magnetic structures. However, nonpolar structures only weakly differing from the obtained polar ones exist due to the weak effect that the field -induced breaking of some symmetries has on the calculated structures. Among those symmetries is the PT (1 over bar ‘) symmetry, preserved for Dirac points found in Cu3TeO6. Our findings establish Cu3TeO6 as a promising playground to study the interplay of spintronics-related phenomena.

Is There a Special Role for Ovarian Hormones in the Pathogenesis of Lobular Carcinoma?

R. L. Flaherty; G. Sflomos; C. Brisken 

Lobular carcinoma represent the most common special histological subtype of breast cancer, with the majority classed as hormone receptor positive. Rates of invasive lobular carcinoma in postmenopausal women have been seen to increase globally, while other hormone receptor-positive breast cancers proportionally have not followed the same trend. This has been linked to exposure to exogenous ovarian hormones such as hormone replacement therapy. Reproductive factors resulting in increased lifetime exposure to endogenous ovarian hormones have also been linked to an increased risk of lobular breast cancer, and taken together, these data make a case for the role of ovarian hormones in the genesis and progression of the disease. In this review, we summarize current understanding of the epidemiological associations between ovarian hormones and lobular breast cancer and highlight mechanistic links that may underpin the etiology and biology.

Stick-slip-to-stick transition of liquid oscillations in a U-shaped tube

A. Bongarzone; F. Gallaire 

The nonlinear decay of oscillations of a liquid column in a U-shaped tube is investigated within the theoretical framework of the projection method formalized by Bongarzone et al. [Chaos 31, 123124 (2021)]. Starting from the full hydrodynamic system supplemented by a phenomenological contact line model, this physics -inspired method uses successive linear eigenmode projections to simulate the relaxation dynamics of liquid oscillations in the presence of sliding triple lines. Each projection is shown to eventually induce a rapid loss of total energy in the liquid motion, thus contributing to its nonlinear damping. A thorough quantitative comparison with experiments by Dollet et al. [Phys. Rev. Lett. 124, 104502 (2020)] demonstrates that, in contradistinction with their simplistic one -degree -of -freedom model, the present approach not only describes well the transient stick -slip dynamics, but also correctly captures the global stick -slip to stick transition, as well as the residual exponentially decaying bulk motion following the arrest of the contact line, which has been so far overlooked by existing theoretical analyses but is clearly attested experimentally. This study offers a further contribution to rationalizing the impact of contact angle hysteresis and its associated solidlike friction on the decay of liquid oscillations in the presence of sliding triple lines.

Opportunities and challenges in design and optimization of protein function

D. Listov; C. A. Goverde; B. E. Correia; S. J. Fleishman 

The field of protein design has made remarkable progress over the past decade. Historically, the low reliability of purely structure-based design methods limited their application, but recent strategies that combine structure-based and sequence-based calculations, as well as machine learning tools, have dramatically improved protein engineering and design. In this Review, we discuss how these methods have enabled the design of increasingly complex structures and therapeutically relevant activities. Additionally, protein optimization methods have improved the stability and activity of complex eukaryotic proteins. Thanks to their increased reliability, computational design methods have been applied to improve therapeutics and enzymes for green chemistry and have generated vaccine antigens, antivirals and drug-delivery nano-vehicles. Moreover, the high success of design methods reflects an increased understanding of basic rules that govern the relationships among protein sequence, structure and function. However, de novo design is still limited mostly to alpha-helix bundles, restricting its potential to generate sophisticated enzymes and diverse protein and small-molecule binders. Designing complex protein structures is a challenging but necessary next step if we are to realize our objective of generating new-to-nature activities.|Recent combinations of structure-based and sequence-based calculations and machine learning tools have dramatically improved protein engineering and design. Although designing complex protein structures remains challenging, these methods have enabled the design of therapeutically relevant activities, including vaccine antigens, antivirals and drug-delivery nano-vehicles.

Impact of beam-coupling impedance on the Schottky spectrum of bunched beam

C. Lannoy; K. Lasocha; T. Pieloni; D. Alves; N. Mounet 

The Schottky monitors of the Large Hadron Collider (LHC) can be used for non-invasive beam diagnostics to estimate various bunch characteristics, such as tune, chromaticity, bunch profile or synchrotron frequency distribution. However, collective effects, in particular beam -coupling impedance, can significantly affect Schottky spectra when large bunch charges are involved. In such conditions, the available interpretation methods are difficult to apply directly to the measured spectra, thus preventing the extraction of beam and machine parameters, which is possible for lower bunch charges. To study the impact of impedance on such spectra, we introduce a method for building Schottky spectra from macro -particle simulations performed with the PyHEADTAIL code, applied to LHC beam conditions. In this case, the use of a standard Fast Fourier Transform (FFT) algorithm to recover the spectral content of the beam becomes computationally intractable memory -wise, because of the relatively short bunch length compared to the large revolution period. To circumvent this difficulty, a semi -analytical method was developed to efficiently compute the Fourier transform. The simulated Schottky spectrum is then compared against theoretical formulas and measurements of Schottky signals previously obtained with lead ion beams in the LHC where impedance effects are expected to be limited. Furthermore, this study provides preliminary interpretations of the impact of beam -coupling impedance on proton Schottky spectra by incorporating longitudinal and transverse resonator -like impedance models into the simulations. A theoretical framework is also introduced for the case of the longitudinal impedance, allowing the extension of the existing theoretical formalism.

Gaussian universality of perceptrons with random labels

F. Gerace; F. Krzakala; B. Loureiro; L. Stephan; L. Zdeborova 

While classical in many theoretical settings-and in particular in statistical physics-inspired works-the assumption of Gaussian i.i.d. input data is often perceived as a strong limitation in the context of statistics and machine learning. In this study, we redeem this line of work in the case of generalized linear classification, also known as the perceptron model, with random labels. We argue that there is a large universality class of high-dimensional input data for which we obtain the same minimum training loss as for Gaussian data with corresponding data covariance. In the limit of vanishing regularization, we further demonstrate that the training loss is independent of the data covariance. On the theoretical side, we prove this universality for an arbitrary mixture of homogeneous Gaussian clouds. Empirically, we show that the universality holds also for a broad range of real data sets.

Diffusion of brain metabolites highlights altered brain microstructure in type C hepatic encephalopathy: a 9.4 T preliminary study

J. Mosso; G. Briand; K. Pierzchala; D. Simicic; A. Sierra et al. 

Introduction Type C hepatic encephalopathy (HE) is a decompensating event of chronic liver disease leading to severe motor and cognitive impairment. The progression of type C HE is associated with changes in brain metabolite concentrations measured by 1H magnetic resonance spectroscopy (MRS), most noticeably a strong increase in glutamine to detoxify brain ammonia. In addition, alterations of brain cellular architecture have been measured ex vivo by histology in a rat model of type C HE. The aim of this study was to assess the potential of diffusion-weighted MRS (dMRS) for probing these cellular shape alterations in vivo by monitoring the diffusion properties of the major brain metabolites.Methods The bile duct-ligated (BDL) rat model of type C HE was used. Five animals were scanned before surgery and 6- to 7-week post-BDL surgery, with each animal being used as its own control. 1H-MRS was performed in the hippocampus (SPECIAL, TE = 2.8 ms) and dMRS in a voxel encompassing the entire brain (DW-STEAM, TE = 15 ms, diffusion time = 120 ms, maximum b-value = 25 ms/mu m2) on a 9.4 T scanner. The in vivo MRS acquisitions were further validated with histological measures (immunohistochemistry, Golgi-Cox, electron microscopy).Results The characteristic 1H-MRS pattern of type C HE, i.e., a gradual increase of brain glutamine and a decrease of the main organic osmolytes, was observed in the hippocampus of BDL rats. Overall increased metabolite diffusivities (apparent diffusion coefficient and intra-stick diffusivity-Callaghan’s model, significant for glutamine, myo-inositol, and taurine) and decreased kurtosis coefficients were observed in BDL rats compared to control, highlighting the presence of osmotic stress and possibly of astrocytic and neuronal alterations. These results were consistent with the microstructure depicted by histology and represented by a decline in dendritic spines density in neurons, a shortening and decreased number of astrocytic processes, and extracellular edema.Discussion dMRS enables non-invasive and longitudinal monitoring of the diffusion behavior of brain metabolites, reflecting in the present study the globally altered brain microstructure in BDL rats, as confirmed ex vivo by histology. These findings give new insights into metabolic and microstructural abnormalities associated with high brain glutamine and its consequences in type C HE.

Teaching about non-deterministic physics: an almost forgotten fundamental contribution of Marie Curie

G. Margaritondo 

The first historical steps of radioactivity research offer an excellent opportunity to teach a key concept of modern physics: non-deterministic phenomena. However, this opportunity is often wasted because of historical misconceptions and of the irrational fear of radioactive effects. We propose here a lecturing strategy – primarily for undergraduate students – based on interesting historical facts. In particular, on a key conceptual contribution by Marie Curie, an attractive figure for the young women and men of today. Paradoxically, this milestone is almost unknown, whereas it should contribute to her immortal fame — perhaps as much as the discovery of radium.

The angiogenic growth of cities

I. Capel-Timms; D. Levinson; B. Lahoorpoor; S. Bonetti; G. Manoli 

Describing the space-time evolution of urban population is a fundamental challenge in the science of cities, yet a complete theoretical treatment of the underlying dynamics is still missing. Here, we first reconstruct the evolution of London (UK) over 180 years and show that urban growth consists of an initial phase of diffusion-limited growth, followed by the development of the railway transport network and a consequential shift from central to suburban living. Such dynamics-which are analogous to angiogenesis in biological systems-can be described by a minimalist reaction-diffusion model coupled with economic constraints and an adaptive transport network. We then test the generality of our approach by reproducing the evolution of Sydney, Australia, from 1851 to 2011. We show that the rail system coevolves with urban population, displaying hierarchical characteristics that remain constant over time unless large-scale interventions are put in place to alter the modes of transport. These results demonstrate that transport schemes are first-order controls of long-term urbanization patterns and efforts aimed at creating more sustainable and healthier cities require careful consideration of population-transport feedbacks.

Learning Weakly Convex Regularizers for Convergent Image-Reconstruction Algorithms

A. Goujon; S. J. Neumayer; M. Unser 

We propose to learn non-convex regularizers with a prescribed upper bound on their weak-convexity modulus. Such regularizers give rise to variational denoisers that minimize a convex energy. They rely on few parameters (less than 15,000) and offer a signal-processing interpretation as they mimic handcrafted sparsity-promoting regularizers. Through numerical experiments, we show that such denoisers outperform convex-regularization methods as well as the popular BM3D denoiser. Additionally, the learned regularizer can be deployed to solve inverse problems with iterative schemes that provably converge. For both CT and MRI reconstruction, the regularizer generalizes well and offers an excellent tradeoff between performance, number of parameters, guarantees, and interpretability when compared to other data-driven approaches.

Euclid: Improving the efficiency of weak lensing shear bias calibration

H. Jansen; M. Tewes; T. Schrabback; N. Aghanim; A. Amara et al. 

To obtain an accurate cosmological inference from upcoming weak lensing surveys such as the one conducted by Euclid, the shear measurement requires calibration using galaxy image simulations. As it typically requires millions of simulated galaxy images and consequently a substantial computational effort, seeking methods to speed the calibration up is valuable. We study the efficiency of different noise cancellation methods that aim at reducing the simulation volume required to reach a given precision in the shear measurement. The more efficient a method is, the faster we can estimate the relevant biases up to a required precision level. Explicitly, we compared fit methods with different noise cancellations and a method based on responses. We used GalSim to simulate galaxies both on a grid and at random positions in larger scenes. Placing the galaxies at random positions requires their detection, which we performed with SExtractor. On the grid, we neglected the detection step and, therefore, the potential detection bias arising from it. The shear of the simulated images was measured with the fast moment-based method KSB, for which we note deviations from purely linear shear measurement biases. For the estimation of uncertainties, we used bootstrapping as an empirical method. We extended the response-based approach to work on a wider range of shears and provide accurate estimates of selection biases. We find that each method we studied on top of shape noise cancellation can further increase the efficiency of calibration simulations. The improvement depends on the considered shear amplitude range and the type of simulations (grid-based or random positions). The response method on a grid for small shears provides the biggest improvement. Here the runtime for the estimation of multiplicative biases can be lowered by a factor of 145 compared to the benchmark simulations without any cancellation. In the more realistic case of randomly positioned galaxies, we still find an improvement factor of 70 for small shears using the response method. Alternatively, the runtime can be lowered by a factor of 7 already using pixel noise cancellation on top of shape noise cancellation. Furthermore, we demonstrate that the efficiency of shape noise cancellation can be enhanced in the presence of blending if entire scenes are rotated instead of individual galaxies.

Randomized flexible GMRES with deflated restarting

Y. Jang; L. Grigori; E. Martin; C. Content 

For a high dimensional problem, a randomized Gram-Schmidt (RGS) algorithm is beneficial in computational costs as well as numerical stability. We apply this dimension reduction technique by random sketching to Krylov subspace methods, e.g. to the generalized minimal residual method (GMRES). We propose a flexible variant of GMRES with the randomized Gram-Schmidt-based Arnoldi iteration to produce a set of basis vectors of the Krylov subspace. Even though the Krylov basis is no longer l2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$l_2$$\end{document} orthonormal, its random projection onto the low dimensional space achieves l2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$l_2$$\end{document} orthogonality. As a result, the numerical stability is observed which turns out to be independent of the dimension of the problem even in extreme scale problems. On the other hand, as the harmonic Ritz values are commonly used in GMRES with deflated restarting to improve convergence, we consider another deflation strategy, for instance disregarding the singular vectors associated with the smallest singular values. We thus introduce a new algorithm of the randomized flexible GMRES with singular value decomposition (SVD)-based deflated restarting. At the end, we carry out numerical experiments in the context of compressible turbulent flow simulations. Our proposed approach exhibits a quite competitive numerical behaviour to existing methods while reducing computational costs.

An interior penalty coupling strategy for isogeometric non-conformal Kirchhoff-Love shell patches

G. Guarino; P. Antolin; A. Milazzo; A. Buffa 

This work focuses on the coupling of trimmed shell patches using Isogeometric Analysis, based on higher continuity splines that seamlessly meet the C 1 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C<^>1$$\end{document} requirement of Kirchhoff-Love-based discretizations. Weak enforcement of coupling conditions is achieved through the symmetric interior penalty method, where the fluxes are computed using their correct variationally consistent expression that was only recently proposed and is unprecedentedly adopted herein in the context of coupling conditions. The constitutive relationship accounts for generically laminated materials, although the proposed tests are conducted under the assumption of uniform thickness and lamination sequence. Numerical experiments assess the method for an isotropic and a laminated plate, as well as an isotropic hyperbolic paraboloid shell from the new shell obstacle course. The boundary conditions and domain force are chosen to reproduce manufactured analytical solutions, which are taken as reference to compute rigorous convergence curves in the L 2 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$L<^>2$$\end{document} , H 1 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$H<^>1$$\end{document} , and H 2 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$H<^>2$$\end{document} norms, that closely approach optimal ones predicted by theory. Additionally, we conduct a final test on a complex structure comprising five intersecting laminated cylindrical shells, whose geometry is directly imported from a STEP file. The results exhibit excellent agreement with those obtained through commercial software, showcasing the method’s potential for real-world industrial applications.

Stress tolerance of lightweight glass-free PV modules for vehicle integration

U. B. Desai; K. Nicolet; S. Prabhudesai; G. Cattaneo; J. Robin et al. 

Electric vehicles (EVs) currently dominate the sales in the automotive market. A big leap in this market can be made by developing a photovoltaic product that can be integrated to an EV, as it can boost the driving range of the EV while reducing the charging frequency. Such vehicle-integrated photovoltaic (VIPV) products are already successfully demonstrated, but they are usually made with glass as a front sheet – making them bulky and limiting their use to the car roofs due to safety reasons. The contemporary focus of the research in the field of VIPV is on developing a product that is lightweight (LW) and easily integrable into the complex shapes of an EV. Therefore, in this work, we present our initial findings on a novel architecture for LW VIPV modules employing polycarbonate (PC) as a front sheet. The mechanical behaviour of the LW module under bending is successfully simulated using finite elements (FE) modelling to predict the fracture of the solar cells, which can then be used as a predictive tool to check the maximal load on the PV body of an EV before cracking the c-Si solar cells. We demonstrate that a change in the temperature of the PC-based LW modules can modify the interspacing between the cells and thus create stress on the connectors. The dog-bone connectors are found to allow almost unconstrained movement of the cells in the module when subjected to variation of temperature. The cell movements may result in mechanical fatigue of the interconnection, which can ultimately result in disconnection of the cells. Initial performance of the dog-bone connectors is investigated by applying mechanical fatigue experiments, which demonstrate that the special geometry of the dog-bone connector could endure a greater number of thermal cycles than a simple prismatic shape would.

On the Arithmetic and Geometric Fusion of Beliefs for Distributed Inference

M. Kayaalp; Y. Inan; E. Telatar; A. H. Sayed 

We study the asymptotic learning rates of belief vectors in a distributed hypothesis testing problem under linear and log-linear combination rules. We show that under both combination strategies, agents are able to learn the truth exponentially fast, with a faster rate under log-linear fusion. We examine the gap between the rates in terms of network connectivity and information diversity. We also provide closed-form expressions for special cases involving federated architectures and exchangeable networks.

Alpha1-antitrypsin improves survival in murine abdominal sepsis model by decreasing inflammation and sequestration of free heme

J. D. Zemtsovski; S. Tumpara; S. Schmidt; V. Vijayan; A. Klos et al. 

Background Excessive inflammation, hemolysis, and accumulation of labile heme play an essential role in the pathophysiology of multi-organ dysfunction syndrome (MODS) in sepsis. Alpha1-antitrypsin (AAT), an acute phase protein with heme binding capacity, is one of the essential modulators of host responses to inflammation. In this study, we evaluate the putative protective effect of AAT against MODS and mortality in a mouse model of polymicrobial abdominal sepsis.Methods Polymicrobial abdominal sepsis was induced in C57BL/6N mice by cecal ligation and puncture (CLP). Immediately after CLP surgery, mice were treated intraperitoneally with three different forms of human AAT-plasma-derived native (nAAT), oxidized nAAT (oxAAT), or recombinant AAT (recAAT)-or were injected with vehicle. Sham-operated mice served as controls. Mouse survival, bacterial load, kidney and liver function, immune cell profiles, cytokines/chemokines, and free (labile) heme levels were assessed. In parallel, in vitro experiments were carried out with resident peritoneal macrophages (MPM phi) and mouse peritoneal mesothelial cells (MPMC).Results All AAT preparations used reduced mortality in septic mice. Treatment with AAT significantly reduced plasma lactate dehydrogenase and s-creatinine levels, vascular leakage, and systemic inflammation. Specifically, AAT reduced intraperitoneal accumulation of free heme, production of cytokines/chemokines, and neutrophil infiltration into the peritoneal cavity compared to septic mice not treated with AAT. In vitro experiments performed using MPMC and primary MPM phi confirmed that AAT not only significantly decreases lipopolysaccharide (LPS)-induced pro-inflammatory cell activation but also prevents the enhancement of cellular responses to LPS by free heme. In addition, AAT inhibits cell death caused by free heme in vitro.Conclusion Data from the septic CLP mouse model suggest that intraperitoneal AAT treatment alone is sufficient to improve sepsis-associated organ dysfunctions, preserve endothelial barrier function, and reduce mortality, likely by preventing hyper-inflammatory responses and by neutralizing free heme.

Quantitative prediction of crystallization in laser powder bed fusion of a Zr-based bulk metallic glass with high oxygen content

N. Sohrabi; T. Ivas; J. Jhabvala; J. E. K. Schawe; J. F. Loffler et al. 

One of the main challenges in the fabrication of bulk metallic glasses (BMGs) via laser-based additive manufacturing (AM) is undesirable crystal phase formation, which usually deteriorates the mechanical properties of the BMG fabricated parts. Understanding the crystallization process therefore helps to manufacture parts with desirable properties. In this study, partially crystallized Zr-based BMG (AMZ4) samples were fabricated via laser powder-bed fusion (LPBF). Samples with a different time delay between each adjacent laser tracks were produced to vary the thermal history during the manufacturing process. Two characteristic thermal effects were decoupled, a global one and a local one. The global thermal effect originates from heat accumulation in the whole sample, increasing the overall sample temperature, reducing local cooling rates from the melt and changing thermal cycles in the heat-affected zones (HAZs). The local thermal effect refers to the contribution of each individual laser-track pass, happening even in the absence of the global effect. As the time delay is increased, the sample has more time to dissipate heat, which implies a reduced influence of the global thermal effects, and therefore lower crystalline fractions. The experiments were designed such as to allow for detailed validations of the thermal fields predicted by a Finite Element (FEM) model of the LPBF process. These were indeed used as an input to predict the crystallized fraction in each AMZ4 sample, using previously measured TTT diagrams. For the first time, quantitative predictions with a numerical model could be made over a wide range of crystallized fractions, and were in good agreement with those measured by DSC. To validate the model, a 0 % crystallized fraction was also simulated, corresponding to optimized printing conditions despite the high oxygen content (>1000 ppm) of the AMZ4 chosen for the experiments. It therefore represents a reliable tool for finding optimal processing parameters of BMGs known to be challenging to print.

A cut-cell method for the numerical simulation of 3D multiphase flows with strong interfacial effects

A. Caboussat; J. Hess; A. Masserey; M. Picasso 

We present a numerical model for the approximation of multiphase flows with free surfaces and strong interfacial effects. The model relies on the multiphase incompressible Navier-Stokes equations, and includes surface tension effects on the interfaces between phases, and contact angles. The volume -of -fluid approach is used to track the interfaces and the free surfaces between the various phases and the ambient air. The numerical method relies on an operator splitting strategy. The space discretization relies on a two -grid approach that uses an unstructured finite element mesh for diffusion phenomena and a structured Cartesian grid for advection phenomena. An adaptive mesh refinement algorithm is incorporated to better track the interfaces and free surfaces on the finite element mesh, and approximate more accurately surface forces. The model is validated through numerical experiments, in particular for emulsion problems.

Speciation of Lanthanide Metal Ion Dopants in Microcrystalline All-Inorganic Halide Perovskite CsPbCl3

D. J. Kubicki; D. Prochowicz; A. Hofstetter; A. Ummadisingu; L. Emsley 

Lanthanides are versatile modulators of optoelectronic properties owing to their narrow optical emission spectra across the visible and near-infrared range. Their use in metal halide perovskites (MHPs) has recently gained prominence, although their fate in these materials has not yet been established at the atomic level. We use cesium-133 solid-state NMR to establish the speciation of all nonradioactive lanthanide ions (La3+, Ce3+, Pr3+, Nd3+, Sm3+, Sm2+, Eu3+, Eu2+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+) in microcrystalline CsPbCl3. Our results show that all lanthanides incorporate into the perovskite structure of CsPbCl3 regardless of their oxidation state (+2, +3).

Can Gas Consumption Data Improve the Performance of Electricity Theft Detection?

W. Liao; R. Zhu; T. Ishizaki; Y. Li; Y. Jia et al. 

Machine learning techniques have been extensively developed in the field of electricity theft detection. However, almost all typical models primarily rely on electricity consumption data to identify fraudulent users, often neglecting other pertinent household information such as gas consumption data. This article aims to explore the untapped potential of gas consumption data, a critical yet overlooked factor in electricity theft detection. In particular, we perform theoretical, qualitative, and quantitative correlation analyses between gas and electricity consumption data. Then, we propose two model-agnostic frameworks (i.e., multichannel network and twin network frameworks) to seamlessly integrate gas consumption data into machine learning models. Simulation results show a significant improvement in model performance when gas consumption data are incorporated using our proposed frameworks. Also, our proposed gas and electricity convolutional neural network, based on the proposed framework, demonstrates superior performance compared to classical and recent machine learning models on datasets with varying fraudulent ratios.

Design and in vitro Characterization of a Wearable Multisensing System for Hydration Monitoring

S. Tonello; A. Zacchini; A. Galli; A. Golparvar; A. Meimandi et al. 

Dehydration is a frequent condition in the elderly and can lead to serious health complications if not compensated timely. Early diagnosis can be problematic, as medical examinations in the hospital would be needed. Fully wearable low-cost multisensing devices for home use could help investigate and prevent critical conditions. We introduce a sensing platform designed for operation in remote healthcare for the elderly. It combines a low-cost, highly customizable flexible inkjet-printed multisensor bracelet, including sensors for body impedance, skin hydration, and temperature monitoring, with a small, low-power front-end circuit and an embedded unit that communicates by a Low Power Wide Area Network (LoRaWAN) transmission interface. We describe individual system components and present in vitro experiments for their characterization. Reported results represent the fundamental proof of concept for the development of a fully operating device that can be used satisfactorily to monitor dehydration in a real-life application scenario.

Gamma-ray Spectroscopy in Low-Power Nuclear Research Reactors

O. V. Pakari; A. Lucas; F. B. Darby; V. P. Lamirand; T. Maurer et al. 

Gamma-ray spectroscopy is an effective technique for radioactive material characterization, routine inventory verification, nuclear safeguards, health physics, and source search scenarios. Gamma-ray spectrometers typically cannot be operated in the immediate vicinity of nuclear reactors due to their high flux fields and their resulting inability to resolve individual pulses. Low-power reactor facilities offer the possibility to study reactor gamma-ray fields, a domain of experiments hitherto poorly explored. In this work, we present gamma-ray spectroscopy experiments performed with various detectors in two reactors: The EPFL zero-power research reactor CROCUS, and the neutron beam facility at the Ohio State University Research Reactor (OSURR). We employed inorganic scintillators (CeBr3), organic scintillators (trans-stilbene and organic glass), and high-purity germanium semiconductors (HPGe) to cover a range of typical-and new-instruments used in gamma-ray spectroscopy. The aim of this study is to provide a guideline for reactor users regarding detector performance, observed responses, and therefore available information in the reactor photon fields up to 2 MeV. The results indicate several future prospects, such as the online (at criticality) monitoring of fission products (like Xe, I, and La), dual-particle sensitive experiments, and code validation opportunities.

Accretion Disk Size and Updated Time-delay Measurements in the Gravitationally Lensed Quasar SDSS J165043.44+425149.3

A. B. Rivera; C. W. Morgan; S. M. Florence; K. Kniezewski; M. Millon et al. 

We analyze variability in 15-season optical lightcurves from the doubly imaged lensed quasar SDSS J165043.44+425149.3 (SDSS1650), comprising five seasons of monitoring data from the Maidanak Observatory (277 nights in total, including the two seasons of data previously presented in Vuissoz et al.), five seasons of overlapping data from the Mercator telescope (269 nights), and 12 seasons of monitoring data from the US Naval Observatory, Flagstaff Station at lower cadence (80 nights). We update the 2007 time-delay measurement for SDSS1650 with these new data, finding a time delay of Delta t AB = – 55.1 – 3.7 + 4.0 days, with image A leading image B. We analyze the microlensing variability in these lightcurves using a Bayesian Monte Carlo technique to yield measurements of the size of the accretion disk at lambda rest = 2420 angstrom, finding a half-light radius of log(r 1/2/cm) = 16.19 – 0.58 + 0.38 assuming a 60 degrees inclination angle. This result is unchanged if we model 30% flux contamination from the broad-line region. We use the width of the Mg ii line in the existing Sloan Digital Sky Survey spectra to estimate the mass of this system’s supermassive black hole, finding M BH = 2.47 x 109 M circle dot. We confirm that the accretion disk size in this system, whose black hole mass is on the very high end of the M BH scale, is fully consistent with the existing quasar accretion disk size-black hole mass relation.

The molecular scale mechanism of deposition ice nucleation on silver iodide

G. Roudsari; M. Lbadaoui-Darvas; A. Welti; A. Nenes; A. Laaksonen 

Heterogeneous ice nucleation is a ubiquitous process in the natural and built environment. Deposition ice nucleation, i.e. heterogeneous ice nucleation that – according to the traditional view – occurs in a subsaturated water vapor environment and in the absence of supercooled water on the solid, ice-forming surface, is among the most important ice formation processes in high-altitude cirrus and mixed-phase clouds. Despite its importance, very little is known about the mechanism of deposition ice nucleation at the microscopic level. This study puts forward an adsorption-based mechanism for deposition ice nucleation through results from a combination of atomistic simulations, experiments and theoretical modelling. One of the most potent laboratory surrogates of ice nucleating particles, silver iodide, is used as a substrate for the simulations. We find that water initially adsorbs in clusters which merge and grow over time to form layers of supercooled water. Ice nucleation on silver iodide requires at minimum the adsorption of 4 molecular layers of water. Guided by the simulations we propose the following fundamental freezing steps: (1) Water molecules adsorb on the surface, forming nanodroplets. (2) The supercooled water nanodroplets merge into a continuous multilayer when they grow to about 3 molecular layers thick. (3) The layer continues to grow until the critical thickness for freezing is reached. (4) The critical ice cluster continues to grow.|Schematic of the proposed deposition ice nucleation mechanism on AgI (0001).

Multi-Ported GC-eDRAM Bitcell with Dynamic Port Configuration and Refresh Mechanism

R. Golman; R. Giterman; A. Teman 

Embedded memories occupy an increasingly dominant part of the area and power budgets of modern systems-on-chips (SoCs). Multi-ported embedded memories, commonly used by media SoCs and graphical processing units, occupy even more area and consume higher power due to larger memory bitcells. Gain-cell eDRAM is a high-density alternative for multi-ported operation with a small silicon footprint. However, conventional gain-cell memories have limited data availability, as they require periodic refresh operations to maintain their data. In this paper, we propose a novel multi-ported gain-cell design, which provides up-to N read ports and M independent write ports (NRMW). In addition, the proposed design features a configurable mode of operation, supporting a hidden refresh mechanism for improved memory availability, as well as a novel opportunistic refresh port approach. An 8kbit memory macro was implemented using a four-transistor bitcell with four ports (2R2W) in a 28 nm FD-SOI technology, offering up-to a 3x reduction in bitcell area compared to other dual-ported SRAM memory options, while also providing 100% memory availability, as opposed to conventional dynamic memories, which are hindered by limited availability.

On the Sums over Inverse Powers of Zeros of the Hurwitz Zeta Function and Some Related Properties of These Zeros

S. Sekatskii 

Recently, we have applied the generalized Littlewood theorem concerning contour integrals of the logarithm of the analytical function to find the sums over inverse powers of zeros for the incomplete gamma and Riemann zeta functions, polygamma functions, and elliptical functions. Here, the same theorem is applied to study such sums for the zeros of the Hurwitz zeta function zeta(s,z), including the sum over the inverse first power of its appropriately defined non-trivial zeros. We also study some related properties of the Hurwitz zeta function zeros. In particular, we show that, for any natural N and small real epsilon, when z tends to n = 0, -1, -2 horizontal ellipsis we can find at least N zeros of zeta(s,z) in the epsilon neighborhood of 0 for sufficiently small |z+n|, as well as one simple zero tending to 1, etc.

Realization of Organocerium-Based Fullerene Molecular Materials Showing Mott Insulator-Type Behavior

P. Pandey; X. Wang; H. Gupta; P. W. Smith; E. Lapsheva et al. 

Electron-rich organocerium complexes (C5Me4H)(3)Ce and [(C5Me5)(2)Ce(ortho-oxa)], with redox potentials E-1/2 = -0.82 V and E-1/2 = -0.86 V versus Fc/Fc(+), respectively, were reacted with fullerene (C-60) in different stoichiometries to obtain molecular materials. Structurally characterized cocrystals: [(C5Me4H)(3)Ce](2)C-60 (1) and [(C5Me5)(2)Ce(ortho-oxa)](3)C-60 (2) of C-60 with cerium-based, molecular rare earth precursors are reported for the first time. The extent of charge transfer in 1 and 2 was evaluated using a series of physical measurements: FT-IR, Raman, solid-state UV-vis-NIR spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy, and magnetic susceptibility measurements. The physical measurements indicate that 1 and 2 comprise the cerium(III) oxidation state, with formally neutral C-60 as a cocrystal in both cases. Pressure-dependent periodic density functional theory calculations were performed to study the electronic structure of 1. Inclusion of a Hubbard-U parameter removes Ce f states from the Fermi level, opens up a band gap, and stabilizes FM/AFM magnetic solutions that are isoenergetic because of the large distances between the Ce(III) cations. The electronic structure of this strongly correlated Mott insulator-type system is reminiscent of the well-studied Ce2O3.

Mean-field transport equations and energy theorem for plasma edge turbulent transport

R. A. J. Coosemans; W. Dekeyser; M. Baelmans 

This paper establishes a mean-field equation set and an energy theorem to provide a theoretical basis in view of the development of self-consistent, physics-based turbulent transport models for mean-field transport codes. A rigorous averaging procedure identifies the exact form of the perpendicular turbulent fluxes which are modelled by ad hoc diffusive terms in mean-field transport codes, next to other closure terms which are not commonly considered. Earlier work suggested that the turbulent $E\times B$ particle and heat fluxes, which are thus identified to be important closure terms, can be modelled to reasonable accuracy using the kinetic energy in the $E\times B$ velocity fluctuations ($k_{E}$). The related enstrophy led to further modelling improvements in an initial study, although further analysis is required. To support this modelling approach, transport equations are derived analytically for both quantities. In particular, an energy theorem is established in which the various source and sink terms of $k_{E}$ are shown to couple to mean-field and turbulent parallel kinetic energy, kinetic energy in the other perpendicular velocity components, the thermal energy and the magnetic energy. This provides expressions for the interchange, drift-wave and Reynolds stress terms amongst others. Note that most terms in these energy equations are in turn closure terms. It is suggested to evaluate these terms using reference data from detailed turbulence code simulations in future work.

Two- and Three-Dimensional Superconducting Phases in the Weyl Semimetal TaP at Ambient Pressure. (vol 10, 288, 2020)

M. R. Van Delft; S. Pezzini; M. Koenig; P. Tinnemans; N. E. Hussey et al. 

Microbial genome collection of aerobic granular sludge cultivated in sequencing batch reactors using different carbon source mixtures

J. S. Saini; A. Adler; L. Cardona; P. N. R. Ramirez; R. Pei et al. 

Aerobic granular sludge (AGS) consists of a microbial consortium that has an important role in wastewater treatment. This study investigates AGS microorganisms cultivated in a laboratory-scale sequencing batch reactor. Metagenomic sequencing was conducted using PacBio and Illumina, resulting in 759 metagenome-assembled genomes, 331 of which remained after dereplication.

The Extraordinary March 2022 East Antarctica “Heat” Wave. Part II: Impacts on the Antarctic Ice Sheet

J. D. Wille; S. P. Alexander; C. Amory; R. Baiman; L. Barthelemy et al. 

Between 15 and 19 March 2022, East Antarctica experienced an exceptional heat wave with widespread 30 degrees-40 degrees C temperature anomalies across the ice sheet. In Part I, we assessed the meteorological drivers that generated an intense atmospheric river (AR) that caused these record-shattering temperature anomalies. Here, we continue our large collaborative study by analyzing the widespread and diverse impacts driven by the AR landfall. These impacts included widespread rain and surface melt that was recorded along coastal areas, but this was outweighed by widespread high snowfall accumulations resulting in a largely positive surface mass balance contribution to the East Antarctic region. An analysis of the surface energy budget indicated that widespread downward longwave radiation anomalies caused by large cloudliquid water contents along with some scattered solar radiation produced intense surface warming. Isotope measurements of the moisture were highly elevated, likely imprinting a strong signal for past climate reconstructions. The AR event attenuated cosmic ray measurements at Concordia, something previously never observed. Last, an extratropical cyclone west of the AR landfall likely triggered the final collapse of the critically unstable Conger Ice Shelf while further reducing an already record low sea ice extent.

The multimodality cell segmentation challenge: toward universal solutions

J. Ma; R. Xie; S. Ayyadhury; C. Ge; A. Gupta et al. 

Cell segmentation is a critical step for quantitative single-cell analysis in microscopy images. Existing cell segmentation methods are often tailored to specific modalities or require manual interventions to specify hyper-parameters in different experimental settings. Here, we present a multimodality cell segmentation benchmark, comprising more than 1,500 labeled images derived from more than 50 diverse biological experiments. The top participants developed a Transformer-based deep-learning algorithm that not only exceeds existing methods but can also be applied to diverse microscopy images across imaging platforms and tissue types without manual parameter adjustments. This benchmark and the improved algorithm offer promising avenues for more accurate and versatile cell analysis in microscopy imaging.|Cell segmentation is crucial in many image analysis pipelines. This analysis compares many tools on a multimodal cell segmentation benchmark. A Transformer-based model performed best in terms of performance and general applicability.

Euclid: The search for primordial features

M. Ballardini; Y. Akrami; F. Finelli; D. Karagiannis; B. Li et al. 

Primordial features, in particular oscillatory signals, imprinted in the primordial power spectrum of density perturbations represent a clear window of opportunity for detecting new physics at high-energy scales. Future spectroscopic and photometric measurements from the Euclid space mission will provide unique constraints on the primordial power spectrum, thanks to the redshift coverage and high-accuracy measurement of nonlinear scales, thus allowing us to investigate deviations from the standard power-law primordial power spectrum. We consider two models with primordial undamped oscillations superimposed on the matter power spectrum described by 1 + A(X) sin (omega(X)Xi(X) + 2 pi phi(X)), one linearly spaced in k space with Xi(lin) equivalent to k/k(*) where k(*) = 0.05 Mpc(-1) and the other logarithmically spaced in k space with Xi(log) equivalent to ln(k/k(*)). We note that AX is the amplitude of the primordial feature, omega(X) is the dimensionless frequency, and phi(X) is the normalised phase, where X = {lin, log}. We provide forecasts from spectroscopic and photometric primary Euclid probes on the standard cosmological parameters Omega(m,0), Omega(b,0), h, ns, and sigma(8), and the primordial feature parameters A(X), omega(X), and phi(X). We focus on the uncertainties of the primordial feature amplitude A(X) and on the capability of Euclid to detect primordial features at a given frequency. We also study a nonlinear density reconstruction method in order to retrieve the oscillatory signals in the primordial power spectrum, which are damped on small scales in the late-time Universe due to cosmic structure formation. Finally, we also include the expected measurements from Euclid’s galaxy-clustering bispectrum and from observations of the cosmic microwave background (CMB). We forecast uncertainties in estimated values of the cosmological parameters with a Fisher matrix method applied to spectroscopic galaxy clustering (GC(sp)), weak lensing (WL), photometric galaxy clustering (GC(ph)), the cross correlation (XC) between GC(ph) and WL, the spectroscopic galaxy clustering bispectrum, the CMB temperature and E-mode polarisation, the temperature-polarisation cross correlation, and CMB weak lensing. We consider two sets of specifications for the Euclid probes (pessimistic and optimistic) and three di fferent CMB experiment configurations, that is, Planck, Simons Observatory (SO), and CMB Stage-4 (CMB-S4). We find the following percentage relative errors in the feature amplitude with Euclid primary probes: for the linear (logarithmic) feature model, with a fiducial value of A(X) = 0.01, omega(X) = 10, and phi(X) = 0.21% (22%) in the pessimistic settings and 18% (18%) in the optimistic settings at a 68.3% confidence level (CL) using GC(sp) +WL +GC(ph) +XC. While the uncertainties on the feature amplitude are strongly dependent on the frequency value when single Euclid probes are considered, we find robust constraints on A X from the combination of spectroscopic and photometric measurements over the frequency range of (1, 10(2.1)). Due to the inclusion of numerical reconstruction, the GC(sp) bispectrum, SO-like CMB reduces the uncertainty on the primordial feature amplitude by 32%-48%, 50%-65%, and 15%-50%, respectively.|Combining all the sources of information explored expected from Euclid in combination with the future SO-like CMB experiment, we forecast A(lin) similar or equal to 0.010 +/- 0.001 at a 68.3% CL and A(log) similar or equal to 0.010 +/- 0.001 for GC(sp)(PS rec + BS) +WL +GC(ph) +XC +SO-like for both the optimistic and pessimistic settings over the frequency range (1, 10(2.1)).

Search for Inelastic Dark Matter in Events with Two Displaced Muons and Missing Transverse Momentum in Proton-Proton Collisions at p s=13 TeV

A. Hayrapetyan; A. Tumasyan; W. Adam; J. W. Andrejkovic; T. Bergauer et al. 

A search for dark matter in events with a displaced nonresonant muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138 fb-1 of protonproton (pp) collision data at a center -of -mass energy of 13 TeV produced by the LHC in 2016-2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section sigma(pp -> A0 -> chi 1 chi 2) and the decay branching fraction B(chi 2 -> chi 1 mu thorn mu-), where A0 is a dark photon and chi 1 and chi 2 are states in the dark sector with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter.

Tumor-educated Gr1+CD11b+cells drive breast cancer metastasis via OSM/IL-6/JAK-induced cancer cell plasticity

S. Peyvandi; M. Bulliard; A. Yilmaz; A. Kauzlaric; R. Marcone et al. 

Cancer cell plasticity contributes to therapy resistance and metastasis, which represent the main causes of cancer-related death, including in breast cancer. The tumor microenvironment drives cancer cell plasticity and metastasis, and unraveling the underlying cues may provide novel strategies for managing metastatic disease. Using breast cancer experimental models as a clinically relevant paracrine/autocrine axis instigating breast cancer cell plasticity and triggering metastasis.

Search for Scalar Leptoquarks Produced via τ-Lepton-Quark Scattering in pp Collisions at ffiffi s p=13 TeV

A. Hayrapetyan; A. Tumasyan; W. Adam; J. W. Andrejkovic; T. Bergauer et al. 

The first search for scalar leptoquarks produced in z-lepton-quark collisions is presented. It is based on a set of proton-proton collision data recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138 fb-1. The reconstructed final state consists of a jet, significant missing transverse momentum, and a z lepton reconstructed through its hadronic or leptonic decays. Limits are set on the product of the leptoquark production cross section and branching fraction and interpreted as exclusions in the plane of the leptoquark mass and the leptoquark-z-quark coupling strength.

Measurement of the K+ → π+γγ decay

E. C. Gil; A. Kleimenova; E. Minucci; S. Padolski; P. Petrov et al. 

A sample of 3984 candidates of the K+ -> pi(+)gamma gamma decay, with an estimated background of 291 +/- 14 events, was collected by the NA62 experiment at CERN during 2017-2018. In order to describe the observed di-photon mass spectrum, the next-to-leading order contribution in chiral perturbation theory was found to be necessary. The decay branching ratio in the full kinematic range is measured to be (9.61 +/- 0.17) x 10(-7). The first search for production and prompt decay of an axion-like particle with gluon coupling in the process K+ -> pi(+) a, a -> gamma gamma is also reported.

Dynamics of the charge transfer to solvent process in aqueous iodide

J. Lan; M. Chergui; A. Pasquarello 

Charge-transfer-to-solvent states in aqueous halides are ideal systems for studying the electron-transfer dynamics to the solvent involving a complex interplay between electronic excitation and solvent polarization. Despite extensive experimental investigations, a full picture of the charge-transfer-to-solvent dynamics has remained elusive. Here, we visualise the intricate interplay between the dynamics of the electron and the solvent polarization occurring in this process. Through the combined use of ab initio molecular dynamics and machine learning methods, we investigate the structure, dynamics and free energy as the excited electron evolves through the charge-transfer-to-solvent process, which we characterize as a sequence of states denoted charge-transfer-to-solvent, contact-pair, solvent-separated, and hydrated electron states, depending on the distance between the iodine and the excited electron. Our assignment of the charge-transfer-to-solvent states is supported by the good agreement between calculated and measured vertical binding energies. Our results reveal the charge transfer process in terms of the underlying atomic processes and mechanisms.|Solvated electrons can be formed through photo-induced charge-transfer-to-solvent electronic states of halide ions in water. Here, the authors use machine learning accelerated molecular dynamics simulations to follow the evolution of these states for aqueous iodide in detail.

Cortical cell assemblies and their underlying connectivity: An in silico study

A. Ecker; D. E. Santander; S. Bolanos-Puchet; J. B. Isbister; M. W. Reimann 

Recent developments in experimental techniques have enabled simultaneous recordings from thousands of neurons, enabling the study of functional cell assemblies. However, determining the patterns of synaptic connectivity giving rise to these assemblies remains challenging. To address this, we developed a complementary, simulation-based approach, using a detailed, large-scale cortical network model. Using a combination of established methods we detected functional cell assemblies from the stimulus-evoked spiking activity of 186,665 neurons. We studied how the structure of synaptic connectivity underlies assembly composition, quantifying the effects of thalamic innervation, recurrent connectivity, and the spatial arrangement of synapses on dendrites. We determined that these features reduce up to 30%, 22%, and 10% of the uncertainty of a neuron belonging to an assembly. The detected assemblies were activated in a stimulus-specific sequence and were grouped based on their position in the sequence. We found that the different groups were affected to different degrees by the structural features we considered. Additionally, connectivity was more predictive of assembly membership if its direction aligned with the temporal order of assembly activation, if it originated from strongly interconnected populations, and if synapses clustered on dendritic branches. In summary, reversing Hebb’s postulate, we showed how cells that are wired together, fire together, quantifying how connectivity patterns interact to shape the emergence of assemblies. This includes a qualitative aspect of connectivity: not just the amount, but also the local structure matters; from the subcellular level in the form of dendritic clustering to the presence of specific network motifs.

Disulfide-Cross-Linked Tetra-PEG Gels

Z. Meng; L. Loeser; K. Saalwaechter; U. Gasser; H-A. Klok 

The preparation of polymer gels via cross-linking of four-arm star-shaped poly(ethylene glycol) (Tetra-PEG) precursors is an attractive strategy to prepare networks with relatively well-defined topologies. Typically, Tetra-PEG gels are obtained by cross-linking heterocomplementary reactive Tetra-PEG precursors. This study, in contrast, explores the cross-linking of self-reactive, thiol-end functional Tetra-PEG macromers to form disulfide-cross-linked gels. The structure of the disulfide-cross-linked Tetra-PEG gels was studied with multiple-quantum NMR (MQ-NMR) spectroscopy and small-angle neutron scattering (SANS) experiments. In line with earlier simulation studies, these experiments showed a strong dependence of the relative fractions of the different network connectivities on the concentration of the thiol-end functional Tetra-PEG macromer that was used for the synthesis of the networks. Disulfide-cross-linked Tetra-PEG gels prepared at macromer concentrations below the overlap concentration (c = 0.66c*) primarily feature defect connectivity motifs, such as primary loops and dangling ends. For networks prepared at macromer concentrations above the overlap concentration, the fraction of single-link connectivities was found to be similar to that in amide-cross-linked Tetra-PEG gels obtained by heterocomplementary cross-linking of N-hydroxysuccinimide ester and amine functional Tetra-PEG macromers. Since disulfide bonds are susceptible to reductive cleavage, these disulfide-cross-linked gels are of interest, e.g., as reduction-sensitive hydrogels for a variety of biomedical applications.

Evaluation of controllers for augmentative hip exoskeletons and their effects on metabolic cost of walking: explicit versus implicit synchronization

A. R. Manzoori; D. Malatesta; J. Primavesi; A. Ijspeert; M. Bouri 

Background: Efficient gait assistance by augmentative exoskeletons depends on reliable control strategies. While numerous control methods and their effects on the metabolic cost of walking have been explored in the literature, the use of different exoskeletons and dissimilar protocols limit direct comparisons. In this article, we present and compare two controllers for hip exoskeletons with different synchronization paradigms. Methods: The implicit-synchronization-based approach, termed the Simple Reflex Controller (SRC), determines the assistance as a function of the relative loading of the feet, resulting in an emerging torque profile continuously assisting extension during stance and flexion during swing. On the other hand, the Hip-Phase-based Torque profile controller (HPT) uses explicit synchronization and estimates the gait cycle percentage based on the hip angle, applying a predefined torque profile consisting of two shorter bursts of assistance during stance and swing. We tested the controllers with 23 naive healthy participants walking on a treadmill at 4 km & sdot; h-1, without any substantial familiarization. Results: Both controllers significantly reduced the metabolic rate compared to walking with the exoskeleton in passive mode, by 18.0% (SRC, p < 0.001) and 11.6% (HPT, p < 0.001). However, only the SRC led to a significant reduction compared to walking without the exoskeleton (8.8%, p = 0.004). The SRC also provided more mechanical power and led to bigger changes in the hip joint kinematics and walking cadence. Our analysis of mechanical powers based on a whole-body analysis suggested a reduce in ankle push-off under this controller. There was a strong correlation (Pearson's r = 0.778, p < 0.001) between the metabolic savings achieved by each participant with the two controllers. Conclusion: The extended assistance duration provided by the implicitly synchronized SRC enabled greater metabolic reductions compared to the more targeted assistance of the explicitly synchronized HPT. Despite the different assistance profiles and metabolic outcomes, the correlation between the metabolic reductions with the two controllers suggests a difference in individual responsiveness to assistance, prompting more investigations to explore the person-specific factors affecting assistance receptivity.

Boosting likelihood learning with event reweighting

S. Chen; A. Glioti; G. Panico; A. Wulzer 

Extracting maximal information from experimental data requires access to the likelihood function, which however is never directly available for complex experiments like those performed at high energy colliders. Theoretical predictions are obtained in this context by Monte Carlo events, which do furnish an accurate but abstract and implicit representation of the likelihood. Strategies based on statistical learning are currently being developed to infer the likelihood function explicitly by training a continuous-output classifier on Monte Carlo events. In this paper, we investigate the usage of Monte Carlo events that incorporate the dependence on the parameters of interest by reweighting. This enables more accurate likelihood learning with less training data and a more robust learning scheme that is more suited for automation and extensive deployment. We illustrate these advantages in the context of LHC precision probes of new Effective Field Theory interactions.

Deconvolution of the X-ray absorption spectrum of trans-1,3-butadiene with resonant Auger spectroscopy

D. M. P. Holland; J. Suchan; J. Janos; C. Bacellar; L. M. Diniz Leroy et al. 

High-resolution carbon K-edge X-ray photoelectron, X-ray absorption, non-resonant and resonant Auger spectra are presented of gas phase trans-1,3-butadiene alongside a detailed theoretical analysis utilising nuclear ensemble approaches and vibronic models to simulate the spectroscopic observables. The resonant Auger spectra recorded across the first pre-edge band reveal a complex evolution of different electronic states which remain relatively well-localised on the edge or central carbon sites. The results demonstrate the sensitivity of the resonant Auger observables to the weighted contributions from multiple electronic states. The gradually evolving spectral features can be accurately and feasibly simulated within nuclear ensemble methods and interpreted with the population analysis.

The Extraordinary March 2022 East Antarctica “Heat” Wave. Part I: Observations and Meteorological Drivers

J. D. Wille; S. P. Alexander; C. Amory; R. Baiman; L. Barthelemy et al. 

Between 15 and 19 March 2022, East Antarctica experienced an exceptional heat wave with widespread 30 degrees-40 degrees C temperature anomalies across the ice sheet. This record-shattering event saw numerous monthly temperature records being broken including a new all-time temperature record of -9.4 degrees C on 18 March at Concordia Station despite March typically being a transition month to the Antarctic coreless winter. The driver for these temperature extremes was an intense atmospheric river advecting subtropical/midlatitude heat and moisture deep into the Antarctic interior. The scope of the temperature records spurred a large, diverse collaborative effort to study the heat wave’s meteorological drivers, impacts, and historical climate context. Here we focus on describing those temperature records along with the intricate meteorological drivers that led to the most intense atmospheric river observed over East Antarctica. These efforts describe the Rossby wave activity forced from intense tropical convection over the Indian Ocean. This led to an atmospheric river and warm conveyor belt intensification near the coastline, which reinforced atmospheric blocking deep into East Antarctica. The resulting moisture flux and upper-level warm-air advection eroded the typical surface temperature inversions over the ice sheet. At the peak of the heat wave, an area of 3.3 million km(2) in East Antarctica exceeded previous March monthly temperature records. Despite a temperature anomaly return time of about 100 years, a closer recurrence of such an event is possible under future climate projections. In Part II we describe the various impacts this extreme event had on the East Antarctic cryosphere.|SIGNIFICANCE STATEMENT: In March 2022, a heat wave and atmospheric river caused some of the highest temperature anomalies ever observed globally and captured the attention of the Antarctic science community. Using our diverse collective expertise, we explored the causes of the event and have placed it within a historical climate context. One key takeaway is that Antarctic climate extremes are highly sensitive to perturbations in the midlatitudes and subtropics. This heat wave redefined our expectations of the Antarctic climate. Despite the rare chance of occurrence based on past climate, a future temperature extreme event of similar magnitude is possible, especially given anthropogenic climate change.

Measurement of the τ lepton polarization in Z boson decays in proton-proton collisions at √s=13 TeV

A. Hayrapetyan; A. Tumasyan; W. Adam; J. W. Andrejkovic; T. Bergauer et al. 

The polarization of tau leptons is measured using leptonic and hadronic tau lepton decays in Z -> tau(+)tau(-) events in proton-proton collisions at root s = 13 TeV recorded by CMS at the CERN LHC with an integrated luminosity of 36.3 fb(-1). The measured tau(-) lepton polarization at the Z boson mass pole is P-tau(Z) = -0.144 +/- 0.006 (stat) +/- 0.014 (syst) = -0.144 +/- 0.015, in good agreement with the measurement of the tau lepton asymmetry parameter of A(tau) = 0.1439 +/- 0.0043 = -P-tau(Z) at LEP. The tau lepton polarization depends on the ratio of the vector to axial-vector couplings of the tau leptons in the neutral current expression, and thus on the effective weak mixing angle sin(2)theta(eff)(W), independently of the Z boson production mechanism. The obtained value sin(2)theta(eff)(W) = 0.2319 +/- 0.0008(stat) +/- 0.0018(syst) = 0.2319 +/- 0.0019 is in good agreement with measurements at e(+)e(-) colliders.

Light-Controlled Multiconfigurational Conductance Switching in a Single 1D Metal-Organic Wire

A. Cahlik; M. Ondracek; C. Wackerlin; A. P. Sole; O. Siri et al. 

Precise control of multiple spin states on the atomic scale presents a promising avenue for designing and realizing magnetic switches. Despite substantial progress in recent decades, the challenge of achieving control over multiconfigurational reversible switches in low-dimensional nanostructures persists. Our work demonstrates multiple, fully reversible plasmon-driven spin-crossover switches in a single pi-d metal-organic chain suspended between two electrodes. The plasmonic nanocavity stimulated by external visible light allows for reversible spin crossover between low- and high-spin states of different cobalt centers within the chain. We show that the distinct spin configurations remain stable for minutes under cryogenic conditions and can be nonperturbatively detected by conductance measurements. This multiconfigurational plasmon-driven spin-crossover demonstration extends the available toolset for designing optoelectrical molecular devices based on SCO compounds.

Redox Properties of Flavin in BLUF and LOV Photoreceptor Proteins from Hybrid QM/MM Molecular Dynamics Simulation

M. Kilic; B. Ensing 

Flavins play an important role in many oxidation and reduction processes in biological systems. For example, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) are common cofactors found in enzymatic proteins that use the special redox properties of these flavin molecules for their catalytic or photoactive functions. The redox potential of the flavin is strongly affected by its (protein) environment; however, the underlying molecular interactions of this effect are still unknown. Using hybrid quantum mechanics/molecular mechanics (QM/MM) simulation techniques, we have studied the redox properties of flavin in the gas phase, aqueous solution, and two different protein environments, in particular, a BLUF and a LOV photoreceptor domain. By mapping the changes in electrostatic potential and solvent structure, we gain insight into how specific polarization of the flavin by its environment tunes the reduction potential. We find also that accurate calculation of the reduction potentials of these systems by using the hybrid QM/MM approach is hampered by a too limited sampling of the counterion configurations and by artifacts at the QM/MM boundary. We make suggestions for how these issues can be overcome.