bluuebunny/crossref_metadata_2025 huggingface dataset:
Making wood inspection easier: FTIR spectroscopy and machine learning for Brazilian native commercial wood species identification
Authors: Jesus Everton , Franca Thiago , Calvani Camila , Lacerda Miller , Gonçalves Daniel , Oliveira Samuel L. , Marangoni Bruno , Cena Cicero
Published: March 2024

Sawdust molecular spectra are used as input data for the machine-learning algorithm to classify/identify different wood species.
Reducing optical reflection loss through textured PEDOT:PSS in hybrid Sn–Pb perovskite solar cells
Authors: Hsu Shih-En , Zhu Wen-Xian , Wu Dong-Tai , Huang Wen-Li , Xue Li-Ting , Huang Chi-Jing , Wang Chang-Hao , Li Yun-Shan , Qiu Wei-Jia , Lin Chieh-Ting
Published: March 2024

This work introduces a pioneering method using polystyrene spheres to fabricate a textured PEDOT:PSS layer, which can notably reduce reflective losses in Sn–Pb PSCs and thus improve the power conversion efficiency.
A transformerless Z‐source photovoltaic grid‐connected inverter with coupled inductor coil
Authors: Dai Yunzhong , Zhang Huaiyu
Published: March 2024

The quasi‐Z‐source H‐bridge grid‐connected inverter (QHGCI) is well known for its advantages of the void of the shoot‐through problem and the high DC‐voltage utilization. But the existence of the common‐mode leakage current in the power frequency cycle, lower power density, and higher thermal stress make it hard applicable to the grid‐penetrating application. Thus with the purpose to conquer the problem relating to the QHGCI, an innovative transformerless Z‐source photovoltaic grid‐connected inverter with a coupled inductor coil (TZPGCI‐CIC) is proposed. The circuitry topology and an unipolar sine pulse width modulation strategy are first introduced in short. Thereafter, the common‐mode voltage in the whole working process is derived and evaluated through the detailed operating mode analysis, in which a constant value of it has been theoretically revealed. Lastly, a prototype platform of TZPGCI‐CIC is set up and its good performance on leakage current suppression, and lower thermal stress are validated with the experimental results.
Sub‐optimal Internet of Thing devices deployment using branch and bound method
Authors: Kim Haesik
Published: March 2024

The Internet of Thing (IoT) network deployments are widely investigated in 4G and 5G systems and will still be key technical systems to drive massive connectivity of 6G systems. In 6G, IoT systems will operate with 6G new technologies such as Integrated Sensing and Communications. The IoT systems of 6G will be a platform to collect information in real world and create new use cases and business models. As the IoT devices and cellular networks are getting smarter, the IoT ecosystem allows us to bridge between human life and digital life and accelerate the transition towards a hyper‐connected world. Optimal and scalable IoT network design has been investigated in many research groups but key challenges in this topic still remain. An IoT devices deployment problem is investigated to minimise the transmission and computation cost among network nodes. The IoT devices deployment problem is formulated as Mixed‐Integer Nonlinear Programming problem. After relaxing the constraints and transforming the problem to a mixed integer linear programming (MILP) problem, the authors propose a new branch and bound (BB) method with a machine learning function and solve the MILP problem as a sub‐optimal solution. In the numerical analysis, the authors evaluate both conventional BB method and the proposed BB method with weighting factors and compare the objective function values, the number of explored nodes, and computational time. The performances of the proposed BB method are significantly improved under the given simulation configuration. The author finds the optimal mapping of IoT devices to fusion nodes.
Overview of the contributions from all lanthanide elements to kilonova opacity in the temperature range from 25 000 to 40 000 K
Authors: Carvajal Gallego H. , Deprince J. , Maison L. , Palmeri P. , Quinet P.
Published: March 2024

Context. It is now well established that the neutron star (NS) merger is at the origin of the production of trans-iron heavy elements in the universe. These elements are therefore present in large quantities in the ejected matter, whose electromagnetic radiation, called kilonova, is characterized by a significant opacity due to the high density of spectral lines belonging to many heavy ions. Among these, the lanthanide ions play an essential role since, with their open 4f subshell, they have a considerable number of transitions that can absorb emitted light. The knowledge of the atomic structure and the radiative parameters of these ions as well as the determination of the corresponding opacities is therefore of paramount importance for the spectral analysis of kilonovae.

Aims. The main goal of the present work is to determine the relative contributions of the different lanthanide elements to the opacity of the emission spectrum of a kilonova in its early phase, that is, a few hours after the NS merger, where the conditions are such that the temperature is between 25 000 and 40 000 K. At these temperatures, the lanthanide ions whose charge states are between V and VII are predominant.

Methods. We used the pseudo-relativistic Hartree–Fock (HFR) method extensively to calculate the relevant atomic data (energy levels, wavelengths, and oscillator strengths) in La-Lu V-VII ions. The corresponding monochromatic opacities were estimated from the expansion formalism.

Results. We calculated the spectroscopic parameters for a total of more than 800 million radiative transitions in all the ions considered. These data were used to estimate the expansion opacities and Planck mean opacities for all the lanthanide elements at early-phase kilonova conditions between 25 000 and 40 000 K, making it possible to deduce the respective contributions of each element as a function of temperature. Atomic calculations were also carried out with the fully relativistic Multiconfiguration Dirac-Hartree-Fock (MCDHF) method in the specific case of the Yb V ion, as the available experimental data had not yet been compared with the theoretical calculations in our previous studies on lanthanide ions.
Energetic particle activity in AD Leo: Detection of a solar-like type-IV burst
Authors: Mohan Atul , Mondal Surajit , Wedemeyer Sven , Gopalswamy Natchimuthuk
Published: March 2024

Context. AD Leo is a young and active M dwarf with high flaring rates across the X-ray-to-radio bands. Flares accelerate particles in the outer coronal layers and often impact exo-space weather. Wide-band radio dynamic spectra let us explore the evolution of particle acceleration activity across the corona. Identifying the emission features and modelling the mechanisms can provide insights into the possible physical scenarios driving the particle acceleration processes.

Aims. We performed an 8 h monitoring of AD Leo across the 550-850 MHz band using upgraded-Giant Metrewave Radio Telescope (uGMRT). The possible flare and post-flare emission mechanisms are explored based on the evolution of flux density and polarisation.

Methods. The python-based module, Visibility Averaged Dynamic spectrum (VISAD), was developed to obtain the visibility-averaged wide-band dynamic spectra. Direct imaging was also performed with different frequency-time averaging. Based on existing observational results on AD Leo and on solar active region models, radial profiles of electron density and magnetic fields were derived. Applying these models, we explored the possible emission mechanisms and magnetic field profile of the flaring active region.

Results. The star displayed a high brightness temperature (TB≈ 1010−1011K) throughout the observation. The emission was also nearly 100% left circularly polarised during bursts. The post-flare phase was characterised by a highly polarised (60–80%) solar-like type IV burst confined above 700 MHz.

Conclusions. The flare emission favours a Z-mode or a higher harmonic X-mode electron cyclotron maser emission mechanism. The >700 MHz post-flare activity is consistent with a type-IV radio burst from flare-accelerated particles trapped in magnetic loops, which could be a coronal mass ejection (CME) signature. This is the first solar-like type-IV burst reported on a young active M dwarf belonging to a different age-related activity population (‘C’ branch) compared to the Sun (‘I’ branch). We also find that a multipole expansion model of the active region magnetic field better accounts for the observed radio emission than a solar-like active region profile.
Supermassive black hole spin evolution in cosmological simulations with OPENGADGET3
Authors: Sala Luca , Valentini Milena , Biffi Veronica , Dolag Klaus
Published: March 2024

Context. The mass and spin of massive black holes (BHs) at the centre of galaxies evolve due to gas accretion and mergers with other BHs. Besides affecting the evolution of relativistic jets, for example, the BH spin determines the efficiency with which the BH radiates energy.

Aims. Using cosmological, hydrodynamical simulations, we investigate the evolution of the BH spin across cosmic time and its role in controlling the joint growth of supermassive BHs and their host galaxies.

Methods. We implemented a sub-resolution prescription that models the BH spin, accounting for both BH coalescence and misaligned accretion through a geometrically thin, optically thick disc. We investigated how BH spin evolves in two idealised setups, in zoomed-in simulations and in a cosmological volume. The latter simulation allowed us to retrieve statistically robust results for the evolution and distribution of BH spins as a function of BH properties.

Results. We find that BHs with MBH ≲ 2 × 107 M⊙ grow through gas accretion, occurring mostly in a coherent fashion that favours spin-up. Above MBH ≳ 2 × 107 M⊙, the gas angular momentum directions of subsequent accretion episodes are often uncorrelated with each other. The probability of counter-rotating accretion and hence spin-down increases with BH mass. In the latter mass regime, BH coalescence plays an important role. The spin magnitude displays a wide variety of histories, depending on the dynamical state of the gas feeding the BH and the relative contribution of mergers and gas accretion. As a result of their combined effect, we observe a broad range of values of the spin magnitude at the high-mass end. Reorientation of the BH spin direction occurs on short timescales (≲ 10 Myr) only during highly accreting phases (ƒEdd ≳ 0.1). Our predictions for the distributions of BH spin and spin-dependent radiative efficiency as a function of BH mass are in very good agreement with observations.
Massive clumps in W43-main: Structure formation in an extensively shocked molecular cloud
Authors: Lin Y. , Wyrowski F. , Liu H. B. , Gong Y. , Sipilä O. , Izquierdo A. , Csengeri T. , Ginsburg A. , Li G. X. , Spezzano S. , Pineda J. E. , Leurini S. , Caselli P. , Menten K. M.
Published: March 2024

Aims. W43-main is a massive molecular complex undergoing starburst activities, located at the interaction of the Scutum arm and the Galactic bar. We aim to investigate the gas dynamics, in particular, the prevailing shock signatures from cloud to clump scales. We also look to assess the impact of shocks on the formation of dense gas and early-stage cores in OB cluster formation processes.

Methods. We carried out NOEMA and IRAM-30 m observations at 3 mm towards five molecular gas clumps in W43 main located within large-scale interacting gas components. We used CH3CCH and H2CS lines to trace the extended gas temperature and CH3OH lines to probe the volume density of the dense gas components (≳105 cm−3). We adopted multiple tracers that are sensitive to different gas density regimes to reflect the global gas motions. The density enhancements constrained by CH3OH and a population of NH2D cores are correlated (in the spatial and velocity domains) with SiO emission, which is a prominent indicator of shock processing in molecular clouds.

Results. The emission of SiO (2–1) is extensive across the region (~4 pc) and it is contained within a low-velocity regime, hinting at a large-scale origin for the shocks. Position-velocity maps of multiple tracers show systematic spatio-kinematic offsets supporting the cloud-cloud collision-merging scenario. We identified an additional extended velocity component in the CCH emission, which coincides with one of the velocity components of the larger scale 13CO (2−1) emission, likely representing an outer, less-dense gas layer in the cloud merging process. We find that the ‘V-shaped’, asymmetric SiO wings are tightly correlated with localised gas density enhancements, which is direct evidence of dense gas formation and accumulation in shocks. The dense gas that is formed in this way may facilitate the accretion of the embedded, massive pre-stellar and protostellar cores. We resolved two categories of NH2D cores: those exhibiting only subsonic to transonic velocity dispersions and those with an additional supersonic velocity dispersion. The centroid velocities of the latter cores are correlated with the shock front seen via SiO. The kinematics of the ~0.1 pc NH2D cores are heavily imprinted by shock activities and may represent a population of early-stage cores forming around the shock interface.
HD 7977 and its possible influence on Solar System bodies
Authors: Dybczyński Piotr A. , Królikowska Małgorzata , Bartczak Przemysław , Podlewska-Gaca Edyta , Kamiński Krzysztof , Tokarek Jakub , Langner Krzysztof , de Bruijne Jos
Published: March 2024

Context. In the latest Gaia third data release, one can find extremely small proper motion components for the star HD 7977. This, together with the radial velocity measurement lead to the conclusion that this star passed very close to the Sun in the recent past.

Aims. Such a very close approach of a one solar mass star must have resulted in noticeable changes in the motion of all Solar System bodies, especially those on less tight orbits, namely long-period comets (LPCs) and transneptunian objects (TNOs). We estimate and discuss these effects.

Methods. Our current knowledge on the solar neighbourhood found in the latest Gaia catalogues allowed us to perform numerical integrations and prepare a list of potential stellar perturbers of LPCs. We used this list, made available in the StePPeD database. To study the past motion of LPCs under the simultaneous action of the Galactic potential and passing stars, we used precise original cometary orbits taken from the current CODE catalogue.

Results. We examined the reliability of the extremely small proper motion of HD 7977 and conclude that this star can be an unresolved binary; however, according to the astrometry covering more than a century, the current Gaia data cannot be ruled out. We present the parameters of a very close passage of this star near the Sun. We also show examples of the strong influence of this passage on the past motion of some LPCs. We also discuss the possible influence of this perturber on other Solar System bodies.

Conclusions. It is possible that 2.47 Myr ago the one solar mass star HD 7977 passed as close as 1000 au from the Sun. Such an event constitutes a kind of dynamical horizon for all studies of the past Solar System bodies’ dynamics.
Up around the bend: A multiwavelength view of the quasar 3C 345
Authors: Röder Jan , Ros Eduardo , Schinzel Frank K. , Lobanov Andrei P.
Published: March 2024

Context. The flat-spectrum radio quasar 3C 345 has been showing γ-ray activity since the mid-2000s, along with activity across the electromagnetic spectrum. A γ-ray burst in 2009 was successfully linked to relativistic outflow in 43 GHz very long baseline interferometry (VLBI) observations and has since also been analyzed using single-dish measurements. A multiwavelength follow-up VLBI observation of the 2009 flare in conjunction with 43 GHz catalog data from the VLBA-BU-BLAZAR and BEAM-ME programs are analyzed in this study in the context of the long-term evolution of the source.

Aims. We aim to probe the innermost few milliarcseconds of the ultracompact 3C 345 jet. To do so, we analyzed the long-term kinematics of the inner jet and discuss the magnetic field morphology at different scales, as well as the origin of the γ-ray emission.

Methods. New observations at 23, 43, and 86 GHz were carried out at ten epochs between 2017 and 2019. We calibrated the 30 datasets using the rPicard pipeline, imaged them in Difmap, and carried out polarization calibration using the GPCAL pipeline. We complemented our VLBI data by 43 GHz observations carried out in the framework of the BEAM-ME and VLBA-BU-BLAZAR monitoring programs.

Results. We find multiple distinct component paths in the inner jet, which together have a helical geometry. The helix appears to be anchored at a stationary feature some 0.16 mas from the 43 GHz VLBI core and has an evolution timescale of about 8 yr. The characteristic bends in the jet morphology are caused by variations in the component ejection angle. We confirm the result of previous studies: the γ-ray emission is caused by relativistic outflow and violent interactions within the jet.
Synchronization of Primitive Automata
Authors: Volkov M.V.
Published: March 2024

We exhibit new conditions under which a primitive automaton is synchronizing. In particular, we show that the primitivity of an automaton forces its synchronizability whenever the automaton has either a letter of defect 1 or a word of rank 2.
Modeling and analysis of process parameters in EDM of Ni35Ti35Zr15Cu10Sn5 high-temperature high entropy shape memory alloy by RSM Approach
Authors: Al-Mousawi Mohammed Ali , Al-Shafaie Saad Hameed , Khulief Zuheir Talib
Published: March 2024

The Electrical Discharge Machining (EDM) technique demonstrates proficiency in fabricating precise and intricate geometries, especially in challenging-to-machine materials like high-entropy shape memory alloys. Analyzing and optimizing machining parameters are crucial for their direct impact on mechanical properties and overall product efficiency. The main responses chosen to evaluate the processes are material removal rate (MRR), electrode wear rate (EWR), and surface roughness (Ra). At the same time, the associated machining conditions were discharge current (Ip), pulse-on time (Ton), and pulse-off time (Toff). EDM is a multi-response process; therefore, the method of Response Surface Methodology (RSM) is utilized to assess the influence of machining parameters on Ni35Ti35Zr15Cu10Sn5 (at%) high-temperature high entropy shape memory alloy (HT-HE-SMA) using a copper electrode. Based on a center composite design (CCD), experiments were analyzed using Minitab19 software. To identify the most influential parameters, a thorough analysis of variance (ANOVA) at various significance levels (5%) was performed, checking the sufficiency of all fitted second-order regression models. Discharge current, pulse-on time, and pulse-off time were identified as significant factors that affect output (MRR, EWR, and Ra). The model adequacy of the current experimental investigation is perfect, with determination coefficients (R2) of 97.82% for MRR, 95.36% for EWR, and 99.53% for Ra.
Simple solution of DC-offset rejection based phase-locked loop for single-phase grid-connected converters
Authors: Bany Issa Mohammad A. , Al Muala Zaid A. , Bello Bugallo Pastora M.
Published: March 2024

Distributed Generators (DG) systems based on Renewable Energy Sources (RES) such as hydro, wind, and solar power plants have been spread widely due to their lower cost and the advanced capability of connecting them with the grid. The power generated from the DG must be shaped to be interfaced with the grid employing power electronics converters. The grid-connected power electronics converters must be synchronized with the grid (i.e., the same fundamental component of the grid frequency, phase, amplitude, and sequence). Synchronization techniques are employed to achieve accurate and fast grid synchronization between the converter and the grid. The existence of (DC-offset) in the input of Phase Locked Loop (PLL) caused synchronization problems as it causes oscillations in the estimated fundamental grid phase, frequency, and amplitude. In addition, the closed-loop system stability can be affected. This work proposes a simple technique for grid synchronization based on PLL with a phase angle correction. The proposed method was developed using Transfer Delay (TD) and Delay Signal Cancelation (DSC) operators; then, the small single model and stability analysis was employed. Several scenarios were developed to compare the proposed method with previous methods using MATLAB/Simulink tool. The scenarios involve introducing phase jumps, DC offsets, and amplitude changes to the grid voltage. Additionally, the grid frequency was also changed. The results show that the proposed PLL can solved the DC-offset problem using any delay time and fully synchronized with the grid. Moreover, the proposed PLL has the fastest dynamic response and shortest synchronization time over the other methods from literature.
Bildgebung bei Großgefäßvaskulitiden
Authors: Bauer Claus-Jürgen , Petzinna Simon Michael , Schäfer Valentin Sebastian
Published: March 2024

Großgefäßvaskulitiden sind rheumatologische Autoimmunerkrankungen, die mit entzündlichen Gefäßwandveränderungen in der arteriellen Strombahn einhergehen und zu vielfältigen Organschäden führen können. Die beiden Hauptformen sind die Riesenzellarteriitis und die Takayasu-Arteriitis.

Als Bildgebungsmodalitäten stehen die Gefäßsonografie mit ihren Stärken in der unmittelbaren Point-of-care-Anwendung (insbesondere in der Riesenzellarteriitisdiagnostik), die Magnetresonanztomografie und Computertomografie mit einer besonders guten Darstellung der Aorta und ihrer Abgänge sowie die 18F-Fluordesoxyglukose-Positronenemissionstomografie (18F-FDG-PET) zur Detektion von Entzündungsherden und der Großgefäßvaskulitisdiagnostik zur Verfügung. Zukünftige Entwicklungen in der bildgebenden Diagnostik von Großgefäßvaskulitiden könnten von Verfahren profitieren, die eine zielgerichtete Darstellung der Gefäßentzündung ermöglichen, wie beispielsweise das Gallium-68 DOTAVAP-P1 PET, welches derzeit am Universitätsklinikum Bonn erforscht wird.
Therapiekontrolle bei Immuntherapien mittels PET/CT
Authors: Wasserloos Anne , Beer Ambros J. , Thaiss Wolfgang
Published: March 2024

In der Therapiekontrolle bei Immuntherapien werden neben klinischen Einschätzungen auch bildgebende Verfahren eingesetzt. Hier gibt es einige Herausforderungen, die bei der Beurteilung beachtet werden müssen. Insbesondere der Pseudoprogress, Hyperprogress, ein heterogenes Therapieansprechen sowie unerwünschte Arzneimittelwirkungen können die Beurteilung des Therapieansprechens erschweren. Im Vergleich zur Computertomografie (CT) oder Magnetresonanztomografie (MRT) können Positronenemissionstomografie (PET)/Computertomografie (CT)-Untersuchungen zusätzliche Informationen liefern und bei der besseren Einordnung von Veränderungen helfen. Sowohl für die Beurteilung mittels CT und MRT als auch mittels PET/CT wurden bereits mehrere Klassifikationssysteme entwickelt, wobei sich für die Therapiebeurteilung mittels PET/CT noch keine Klassifikation als Standard im klinischen Alltag etabliert hat.
Immuntherapie mit Checkpointinhibitoren und schilddrüsentypische Komplikationen
Authors: Kreppel Barbara
Published: March 2024

Die Therapie mit Immuncheckpointinhibitoren findet in den letzten Jahren zunehmend Anwendung bei der Therapie einer Vielzahl onkologischer Erkrankungen. Schilddrüsenfunktionsstörungen stellen eine der häufigsten unerwünschten Nebenwirkungen unter diesen Therapien dar. Initial kommt es häufig zu einer transienten, zerfallsbedingten Hyperthyreose, die dann in eine Hypothyreose übergeht. Der genaue pathophysiologische Mechanismus ist jedoch noch nicht hinreichend geklärt. Die Verläufe können asymptomatisch sein; nicht selten kommt es jedoch zu hyper- und hypothyreosetypischen Symptomen, die unter Umständen erst spät einer Schilddrüsenfunktionsstörung zugeordnet werden, da diese letztlich unspezifisch und auch im Rahmen der onkologischen Grunderkrankung denkbar sind. Daher ist bei Verdacht auf das Vorliegen eine fachspezifische Vorstellung beim Nuklearmediziner wichtig zur gezielten Diagnostik mittels Anamnese, Labor, Sonografie und ggf. auch Szintigrafie um weitere Differenzialdiagnosen auszuschließen. Bei Auftreten einer Hyperthyreose steht die symptomatische Therapie im Vordergrund; der Einsatz von Thyreostatika ist nur eingeschränkt zu empfehlen. Eine Hypothyreose sollte mit einer an den TSH-Wert und die Klinik angepassten Schilddrüsenhormonsubstitution therapiert werden. Bis ein stabiler Zustand erreicht ist, sollten dem Krankheitsverlauf angepasste fachspezifische Vorstellungen erfolgen. Im Regelfall kann die Immuntherapie ohne Unterbrechung fortgeführt werden.
Subkutane Applikation von Protonenpumpeninhibitoren – was ist bekannt?
Authors: Berner Jennifer , Rémi Constanze
Published: March 2024

In der Palliativversorgung ist die subkutane Applikationsroute als Alternative zur intravenösen Anwendung weit verbreitet. Bei einigen Arzneistoffen liegen nur wenige Daten zur Sicherheit dieses Applikationswegs vor. Hierzu zählen die Protonenpumpeninhibitoren (PPI) Omeprazol, Esomeprazol und Pantoprazol. Auf Basis einer Literaturrecherche (Medline Datenbank) wurde die verfügbare Evidenz zur subkutanen Applikation von PPI evaluiert. Sieben Publikationen wurden in die Auswertung eingeschlossen. Die subkutane Applikation der drei PPI ist in der Literatur in Fallberichten und Beobachtungsstudien mit geringer Fallzahl beschrieben, überwiegend als subkutane Kurzinfusion mit meist guter Verträglichkeit.
Erwachsene interprofessionell versorgen – Autismus-Spektrum-Störung
Authors: Stiehl Simon , Witzmann Markus , Prommersberger Matthias , Dose Matthias
Published: March 2024

Vor allem im Erwachsenenalter sind Autismus-Spektrum-Störungen (ASS) sehr individuell und vielschichtig. Sie können mit unterschiedlichen körperlichen und psychischen Komorbiditäten einhergehen. Für eine ganzheitliche, ressourcenorientierte Versorgung ist eine hohe interdisziplinäre Handlungskompetenz nötig, die die medizinisch-therapeutische Diagnostik und Behandlung, spezifische Versorgung sowie Unterstützung bei Rehabilitation bzw. Teilhabe umfasst.
Visuelle Wahrnehmung messen – Assessment: FEW-3
Authors: Neugebauer Erika
Published: March 2024

Die dritte Version von Frostigs Entwicklungstest der visuellen Wahrnehmung (FEW-3) löst die Vorgängerversion, den FEW-2, ab. Zu den Neuerungen gehört zum Beispiel die Ausweitung der Altersspanne auf 4–11 Jahre. Der Artikel gibt einen Überblick über den Test sowie die wichtigsten Veränderungen.
Unsichtbare Symptome im Gepäck – Blick in die Medizin: ME/CFS
Authors: Gerasch Leonie
Published: March 2024

Die Häufigkeit der Myalgischen Enzephalomyelitis/des chronischen Fatigue-Syndroms hat mit der Corona-Pandemie zugenommen. Trotzdem ist die Erkrankung noch weitestgehend unbekannt. In der Ergotherapie könnten uns in Zukunft vermehrt Klient*innen mit ME/CFS begegnen, da diese erhebliche Einschränkungen in ihren Betätigungen erleben.
Exploring the link between financial literacy and business interruption insurance: evidence from Italian micro-enterprises
Authors: Ricci Ornella , Santilli Gianluca
Published: March 2024

This article examines the relationship between financial literacy and business interruption (BI) insurance among Italian entrepreneurs. Following an increase in unexpected shocks, such as COVID-19 and geopolitical conflicts, a high level of BI risk is expected to persist, especially among small firms, which play a key role in the Italian economy. Using a Bank of Italy 2021 survey of 1998 non-financial firms with fewer than 10 employees, we show a significant positive association between the level of the entrepreneur’s financial literacy and the purchase of BI insurance. Our results highlight the key role of financial literacy in shaping risk management strategies and are robust to different model specifications, also addressing endogeneity concerns.
The concentration and cavitation in the Riemann solution for non-homogeneous logrithmic equation of state with magnetic field
Authors: Pradeep  , Chaturvedi Rahul Kumar , Singh L. P.
Published: March 2024

In the present study, the phenomena of concentration and cavitation in the Riemann solution for the non-homogeneous hyperbolic system with logarithmic equation of state and magnetic field is analyzed. Firstly, we introduced new state variable for the velocity to modify the non-conservative system into conservative system and solved the Riemann problem for modified system constructively. Further, the Riemann solutions for the transport equations is investigated as pressure and magnetic field vanish. It is proved that the Riemann solution for the non-homogeneous hyperbolic system with logarithmic equation of state and magnetic field having two shock waves converges to the delta shock wave solution of the transport equations as pressure and magnetic field vanish. It is also proved that the Riemann solution for the non-homogeneous hyperbolic system with logarithmic equation of state and magnetic field having two rarefaction waves converges to the contact discontinuity solution of the transport equations as pressure and magnetic field vanish.
Global existence of the strong solution to the climate dynamics model with topography effects and phase transformation of water vapor
Authors: Lian Ruxu , Ma Jieqiong , Zeng Qingcun
Published: March 2024

This study investigates a climate dynamics model that incorporates topographical effects and the phase transformation of water vapor. The system comprises the Navier–Stokes equations, the temperature equation, the specific humidity equation, and the water content equation, all adhering to principles of energy conservation. Applying energy estimation methods, the Helmholtz–Weyl decomposition theorem, and the Brezis–Wainger inequality, we derive high-order a priori estimates for state functions. Subsequently, based on the initial data assumptions V0 ∈ H4(Ω), T0′,q0,mw0∈H2(Ω), we can prove that a strong solution to this system exists globally in time and establish the uniqueness of the global strong solution.
L
∞
-structures and cohomology theory of compatible O-operators and compatible dendriform algebras
Authors: Das Apurba , Guo Shuangjian , Qin Yufei
Published: March 2024

The notion of O-operator is a generalization of the Rota–Baxter operator in the presence of a bimodule over an associative algebra. A compatible O-operator is a pair consisting of two O-operators satisfying a compatibility relation. A compatible O-operator algebra is an algebra together with a bimodule and a compatible O-operator. In this paper, we construct a graded Lie algebra and an L∞-algebra that respectively characterize compatible O-operators and compatible O-operator algebras as Maurer–Cartan elements. Using these characterizations, we define cohomology of these structures and as applications, we study formal deformations of compatible O-operators and compatible O-operator algebras. Finally, we consider a brief cohomological study of compatible dendriform algebras and find their relationship with the cohomology of compatible associative algebras and compatible O-operators.
Parylene-bonded micro-fluidic channels for cryogenic experiments at superfluid He-4 temperatures
Authors: Midlik Š. , Gablech I. , Goleňa M. , Brodský J. , Schmoranzer D.
Published: March 2024

We present the manufacturing process of a (24.5 × 100) μm2-sized on-chip flow channel intended for flow experiments with normal and superfluid phases of 4He and showcase such a proof-of-concept experiment. This work proves the suitability of chip-to-chip bonding using a thin layer of Parylene-C for cryogenic temperatures as a simpler alternative to other techniques, such as anodic bonding. A monocrystalline silicon chip embeds the etched meander-shaped micro-fluidic channel and a deposited platinum heater and is bonded to a Pyrex glass top. We test the leak tightness of the proposed bonding method for superfluid 4He, reaching temperatures of ≈1.6 K and evaluate its possible effects on flow experiments. We demonstrate that powering an on-chip platinum heater affects the superfluid flow rate by local overheating of a section of the micro-fluidic channel.
Analysis of the chemical diffusion master equation for creation and mutual annihilation reactions
Authors: Lanconelli Alberto , Perçin Berk Tan
Published: March 2024

We propose an infinite dimensional generating function method for finding the analytical solution of the so-called chemical diffusion master equation (CDME) for creation and mutual annihilation chemical reactions. CDMEs model by means of an infinite system of coupled Fokker–Planck equations the probabilistic evolution of chemical reaction kinetics associated with spatial diffusion of individual particles; here, we focus an creation and mutual annihilation chemical reactions combined with Brownian diffusion of the single particles. Using our method we are able to link certain finite dimensional projections of the solution of the CDME to the solution of a single linear fourth order partial differential equation containing as many variables as the dimension of the aforementioned projection space. Our technique extends the one presented in Lanconelli [J. Math. Anal. Appl. 526, 127352 (2023)] and Lanconelli et al. [arXiv:2302.10700 [math.PR] (2023)] which allowed for an explicit representation for the solution of birth-death type CDMEs.
A near-infrared laser dispersion spectrometer with phase modulation for open-path methane sensing
Authors: Wall Thomas E. , Macleod Neil A. , Weidmann Damien
Published: March 2024

A laser-based open-path dispersion spectrometer for measuring atmospheric methane has been developed with the goal of achieving a very simple architecture, yet enabling molecular dispersion measurements immune to optical power variation. Well-mature, near-infrared photonics components were retained to demonstrate a compact, cost-effective, and low-power consumption dispersion spectrometer. In particular, measurements immune to received optical power variations are demonstrated despite the use of only phase modulation and are supported by the development of the corresponding physical model. The instrument has been validated under laboratory conditions, finding a precision of 2.6 ppb 100 m for a 2 s measurement, and demonstrated through atmospheric measurements performed continuously over six days with an 86 m path length.
Infrared vertical external cavity surface emitting laser threshold magnetometer
Authors: Gottesman Nathan S. , Slocum Michael A. , Sevison Gary A. , Wolf Michael , Lukowski Michal L. , Hessenius Chris , Fallahi Mahmoud , Bedford Robert G.
Published: March 2024

Nitrogen-vacancy (NV) centers have considerable promise as high sensitivity magnetometers; however, they are commonly limited by inefficient collection and low contrasts. Laser threshold magnetometry (LTM) enables efficient collection and high contrasts, providing a path toward higher sensitivity magnetometry. We demonstrate an infrared LTM using an ensemble of NV centers in a single-crystal diamond plate integrated into a vertical external cavity surface emitting laser. The laser was tuned to the spin-dependent absorption line of the NV centers, allowing for optical readout by monitoring the laser output power. We demonstrate a magnetic sensitivity of 7.5 nT/Hz in the frequency range between 10 and 50 Hz. Furthermore, the contrast and the projected photon shot noise limited (PSNL) sensitivity are shown to improve significantly by operating close to the lasing threshold, achieving 18.4% and 26.6 pT/Hz near the threshold. In addition, an unexpected saturable absorption phenomenon was observed near the threshold, which enhanced the contrast and projected PSNL sensitivity.
The distribution and segregation behaviors of helium in tungsten Σ5(310)/[001] grain boundary region: A first-principles study
Authors: Wu Mingyu , Zhang Yujuan , Li Yungang , Hussain Muhammad Irfan , Jin Jingyuan , Li Sifan , Zhang Yu , Ge Changchun
Published: March 2024

In this work, the distribution and segregation behaviors of helium (He) and the effect of yttrium (Y) on these behaviors in the symmetrical tilt tungsten (W) Σ5(310)/[001] grain boundary (GB) region were studied using first-principles calculations. The results revealed that the GB has a significant impact on the behaviors of He in W. The solution and segregation energies of He in the W Σ5(310)/[001] GB region increase with increasing the distance from He to the GB and are inversely proportional to the effective electrons of He. The density of states analysis showed that the GB can suppress partial hybridization between He and W atoms. In addition, we find that the strengthening element Y facilitates the dissolution of He in the W GB region.
Compact remanence-free permanent magnet-based variable magnetic field source
Authors: Ivanov S. , Chen H. , Szurek M. , Urazhdin S.
Published: March 2024

We demonstrate a simple and compact variable magnetic field source based on the permanent cube magnet array approximating a Halbach cylinder. The large air gap area accommodates standard cryostat tails while providing a high uniformity and magnetic field stability of up to 0.5 T over regions of up to about a centimeter. It eliminates magnetic remanence effects and produces reproducible fields without the need for feedback. Thanks to the low cost and exceptional energy efficiency, it provides an accessible solution for modest magnetic field requirements in a wide range of research applications.
Collisional-radiative modeling of shock-heated nitrogen mixtures
Authors: Aiken Timothy T. , Boyd Iain D.
Published: March 2024

A three-temperature collisional-radiative model for shock-heated nitrogen–argon mixtures is developed to facilitate the study of nonequilibrium electronic excitation and ionization behind strong shock waves. Model predictions accurately reproduce measurements of N2 dissociation for mixtures of 2%–10% N2 in argon, with some discrepancies observed for 20% N2 mixtures. Potential causes of the discrepancies are discussed. Net dissociation in mixtures containing 20% N2 is significantly impacted by the dissociation of N2(A), the first excited electronic state of N2, indicating that molecular electronic excitation can affect net dissociation in shock-heated nitrogen flows. The collisional-radiative model successfully predicts the three-stage behavior and induction time observed in concentration measurements of atomic nitrogen in its fourth excited state, the 3s4P level, behind reflected shocks. Mechanisms for the observed behavior are discussed, which deviate from those inferred using a simpler kinetic model. Excited state number density predictions are strongly influenced by the modeling of radiation self-absorption and the inclusion of the measured non-ideal pressure rise. At higher N2 concentrations, the measured data indicate increased efficiency of atomic nitrogen electronic excitation in collisions with N as compared to collisions with N2 and Ar. A global sensitivity analysis of the excited state predictions is then performed, identifying the processes in the kinetic model that most sensitively influence the predicted excited state time history and further clarifying the dominant mechanisms affecting the experimental observables.
Machine-learning accelerated structure search for ligand-protected clusters
Authors: Fang Lincan , Laakso Jarno , Rinke Patrick , Chen Xi
Published: March 2024

Finding low-energy structures of ligand-protected clusters is challenging due to the enormous conformational space and the high computational cost of accurate quantum chemical methods for determining the structures and energies of conformers. Here, we adopted and utilized a kernel rigid regression based machine learning method to accelerate the search for low-energy structures of ligand-protected clusters. We chose the Au25(Cys)18 (Cys: cysteine) cluster as a model system to test and demonstrate our method. We found that the low-energy structures of the cluster are characterized by a specific hydrogen bond type in the cysteine. The different configurations of the ligand layer influence the structural and electronic properties of clusters.
Primary breakup of liquid jet—Effect of jet velocity profile
Authors: Srinivasan Balaji , Sinha Anubhav
Published: March 2024

The present work examines the effect of the velocity profile on primary breakup of liquid jets emanating from fuel injectors. Direct numerical simulation is used to simulate liquid jet breakup. Different velocity profiles are imposed on the liquid and their effect on breakup is examined. It is a common practice in the literature to use flat or uniform velocity profiles in such studies. The validity of this assumption is assessed and its implications are highlighted. Droplet sizes and degree of atomization are compared for all the cases. Further, a detailed comparison of jet breakup structure is made for two cases—parabolic and power-law velocity profiles. The liquid surface is observed to show two-dimensional waves initially, which subsequently transform into three-dimensional waves and give rise to ligament formation and surface breakup. Tip vortex rollup and its role in jet breakup is discussed. The distinction between different velocity profiles is examined in detail in terms of surface waves, degree of atomization, and jet structure.
A thermal lattice Boltzmann model for evaporating multiphase flows
Authors: Liang Hong , Liu Wenyong , Li Yang , Wei Yikun
Published: March 2024

Modeling thermal multiphase flows has become a widely sought methodology due to its scientific relevance and broad industrial applications. Much progress has been achieved using different approaches, and the lattice Boltzmann method is one of the most popular methods for modeling liquid–vapor phase change. In this paper, we present a novel thermal lattice Boltzmann model for accurately simulating liquid–vapor phase change. The proposed model is built based on the equivalent variant of the temperature governing equation derived from the entropy balance law, in which the heat capacitance is absorbed into transient and convective terms. Then a modified equilibrium distribution function and a proper source term are elaborately designed in order to recover the targeting equation in the incompressible limit. The most striking feature of the present model is that the calculations of the Laplacian term of temperature, the gradient term of temperature, and the gradient term of density can be simultaneously avoided, which makes the formulation of the present model is more concise in contrast to all existing lattice Boltzmann models. Several benchmark examples, including droplet evaporation in open space, droplet evaporation on a heated wall, and nucleate boiling phenomenon, are carried out to assess numerical performance of the present model. It is found that the present model effectively improves the numerical accuracy in solving the interfacial behavior of liquid–vapor phase change within the lattice Boltzmann method framework.
WZW in the lightlike directions
Authors: Gustavsson Andreas
Published: March 2024

Dimensional reduction of the M5 brane on a Lorentzian manifold along a lightlike direction results in a five-dimensional gauge theory, which can be reformulated covariantly in six dimensions, where one puts the Lie derivatives along the lightlike direction of all fields to zero up to a gauge equivalence as constraints. We find gauge and supersymmetry anomalies for certain Lorentzian six-manifolds. We cancel these anomalies by adding a certain WZW theory in the 2d space that is spanned by two lightlike directions.
Dynamic diffusive interfacial transport (D-DIT): A novel quantitative swelling technique for developing binary phase diagrams of aqueous surfactant systems
Authors: Kelkar Parth U. , Erk Kendra A. , Lindberg Seth
Published: March 2024

Current methods to develop surfactant phase diagrams are time-intensive and fail to capture the kinetics of phase evolution. Here, the design and performance of a quantitative swelling technique to study the dynamic phase behavior of surfactants are described. The instrument combines cross-polarized optical and short-wave infrared imaging to enable high-resolution, high-throughput, and in situ identification of phases and water compositions. Data across the entire composition spectrum for the dynamics and phase evolution of a binary aqueous non-ionic surfactant solution at two isotherms are presented. This instrument provides pathways to develop non-equilibrium phase diagrams of surfactant systems—critical to predicting the outcomes of formulation and processing. It can be applied to study time-dependent material relationships across a diverse range of materials and processes, including the dissolution of surfactant droplets and the drying of aqueous polymer films.
Regularity and uniqueness of global solutions for the 3D compressible micropolar fluids
Authors: Zhang Mingyu
Published: March 2024

This paper concerns the regularity and uniqueness of 3D compressible micropolar fluids in the whole space R3. We first establish some new Lp gradient estimates of the solutions for the system, then by virtue of the “div-rot” decomposition technique, the key estimates ‖∇u‖L3 and ‖∇w‖L3 are obtained. As a result, the existence and uniqueness of global solutions belonging to a new class of functions are obtained, provided the initial energy is suitable small. It is worth noting that compared with the existing results, this paper has lower regularity of initial data.
Numerical study for two models in chromatography using modified Rusanov scheme
Authors: Mohamed Kamel , Almatrafi M. B. , Abdelrahman Mahmoud A. E.
Published: March 2024

We investigate the conservation laws that explain the chemistry process of isolating a single component from a mixture using column chromatography. We construct the modified Rusanov (mR) technique to solve the chromatography system. This technique is divided into two parts, the first of which is reliant on a local parameter which enables diffusion control. The conservation equation is recovered in stage two. It is crucial to make sure the numerical approach is built in a way that it is conservative on the overlap and, additionally, that the approximative solutions converge to the weak solution. This strategy is clear-cut, not difficult to use and precise. We compare the mR scheme via the Rusanov scheme and Lax–Friedrichs scheme via five test cases. This numerical research validates the mR scheme's efficacy. Finally, the mR approach can be utilized to solve a variety of conservation laws arising in natural science.