bluuebunny/crossref_metadata_2025 huggingface dataset:
Slow solar wind sources
Authors: Barczynski Krzysztof , Harra Louise , Schwanitz Conrad , Janitzek Nils , Berghmans David , Auchère Frédéric , Aznar Cuadrado Regina , Buchlin Éric , Kraaikamp Emil , Long David M. , Mandal Sudip , Parenti Susanna , Peter Hardi , Rodriguez Luciano , Schühle Udo , Smith Phil , Teriaca Luca , Verbeeck Cis , Zhukov Andrei N.
Published: March 2023

Context. The origin of the slow solar wind is still an open issue. One possibility that has been suggested is that upflows at the edge of an active region can contribute to the slow solar wind.

Aims. We aim to explain how the plasma upflows are generated, which mechanisms are responsible for them, and what the upflow region topology looks like.

Methods. We investigated an upflow region using imaging data with the unprecedented temporal (3 s) and spatial (2 pixels = 236 km) resolution that were obtained on 30 March 2022 with the 174 Å channel of the Extreme-Ultraviolet Imager (EUI)/High Resolution Imager (HRI) on board Solar Orbiter. During this time, the EUI and Earth-orbiting satellites (Solar Dynamics Observatory, Hinode, and the Interface Region Imaging Spectrograph, IRIS) were located in quadrature (∼92°), which provides a stereoscopic view with high resolution. We used the Hinode/EIS (Fe XII) spectroscopic data to find coronal upflow regions in the active region. The IRIS slit-jaw imager provides a high-resolution view of the transition region and chromosphere.

Results. For the first time, we have data that provide a quadrature view of a coronal upflow region with high spatial resolution. We found extended loops rooted in a coronal upflow region. Plasma upflows at the footpoints of extended loops determined spectroscopically through the Doppler shift are similar to the apparent upward motions seen through imaging in quadrature. The dynamics of small-scale structures in the upflow region can be used to identify two mechanisms of the plasma upflow: Mechanism I is reconnection of the hot coronal loops with open magnetic field lines in the solar corona, and mechanism II is reconnection of the small chromospheric loops with open magnetic field lines in the chromosphere or transition region. We identified the locations in which mechanisms I and II work.
Latest results from the DAMPE space mission
Authors: Cagnoli Irene , De Mitri Ivan , Silveri Leandro
Published: March 2023

The space-based DAMPE (DArk Matter Particle Explorer) particle detector has been taking data for more than 7 years since its successful launch in December 2015. Its main scientific goals include the indirect search for dark matter signatures in the cosmic lepton and gamma-ray spectra, the study of galactic cosmic rays up to energies of hundreds of TeV and studies on highenergy gamma ray astronomy. The measurement of galactic cosmic ray spectra are reported here, those being fundamental tools to investigate the mechanisms of acceleration at their sources and propagation through the interstellar medium. Results on proton and helium, which revealed new spectral features, are described. Ongoing analyses on the cosmic ray light, medium and heavy mass nuclei are outlined, together with studies of the so-called secondary cosmic rays. Latest results on gamma-ray astronomy and dark matter search will be also summarized.
LHAASO Status and Physics Results
Authors: Cao Zhen
Published: March 2023

Status of the LHAASO experiment and its latest results in both γ-ray astronomic observations and charged cosmic ray (CR) measurements are reported in this paper. The discovery of photons around 1 PeV from the Crab, 12 PeVatrons in our galaxy and new sources with emissions above 100 TeV declare the onset of the utral-high-energy γ-ray astronomy. The capability of measurements of spectra of the individual species of CRs, e.g. protons and iron nuclei, starts the new era of the high precision measurement of CRs using the ground based extensive air shower technique. The detection of the highest energy photon at 1.4 PeV from the remote potential source in Cygnus region allows to test of the violation of fundamental physics rules, such as the Lorentz Invariance, and set the highest limits in the tests.
Very high energy sky monitoring with the Southern Widefield Gamma-ray Observatory
Authors: La Mura Giovanni , Barres de Almeida Ulisses , Longo Francesco
Published: March 2023

The Southern Wide-field Gamma-ray Observatory (SWGO) is the proposal for a new ground-based γ-ray instrument in the Southern Hemisphere, which will use an array of water-Cherenkov particle detectors to provide continuous monitoring of a large portion of the sky at the very- and ultra-high-energies (VHE and UHE, respectively). At the low energy side, SWGO aims to push the observational range of wide-field ground-based γ-ray facilities down to a few hundred GeV, thus bridging the gap between space and ground-based facilities in the monitoring of the VHE sky. In the high energy domain, on the contrary, it will benefit from the optimal coverage of the Galactic Plane to map the distribution of UHE sources in the inner parts of the Galactic disk and close to the Galactic Center, leading to an extraordinary improvement in our ability to identify their most likely counterparts. In this contribution, we describe the concept of SWGO and its potential to constrain the physics of VHE emission and particle acceleration in γ-ray sources powered by relativistic jets and energetic shocks. We finally discuss its role within the global network of multi-messenger facilities.
Primordial Black Holes as dark matter candidates: Constraints from the diffuse MeV emission
Authors: Berteaud Joanna , Francesca Calore , Iguaz Joaquim , Serpico Pasquale Dario , Siegert Thomas
Published: March 2023

For more than 20 years, the Compton telescope had provided the best measurements of the Galactic diffuse MeV spectrum. Recently, our analysis of 16 years of data from the SPectrometer on INTEGRAL (SPI) measured this emission with a higher signal-to-noise ratio. At MeV energies, the dominant contribution to the diffuse emission comes from inverse Compton scattering. Nonetheless, sub-dominant emission from Primordial Black Hole (PBH) Dark Matter (DM) can be searched for in these data. Hypothetically formed from the collapse of over-densities before Big Bang nucleosynthesis, PBHs are interesting candidates for DM in the ΛCDM model of cosmology. PBHs of masses between 1016 and 1018 g, in the so-called asteroid mass range, are currently unconstrained and can saturate the DM cosmological abundance. MeV emission from PBH in this mass range is expected to come from PBH evaporation. We searched for the PBH signal with 16 years of SPI data, and demonstrated that PBHs cannot account for all the DM if their mass is smaller than 4 × 1017 g.
The multi-PMT optical module of KM3NeT
Authors: Rea Immacolata Carmen
Published: March 2023

The KM3NeT Collaboration has developed a multi-PMT optical so lution for construction of the two deep-sea ARCA and ORCA telescopes. This approach has several advantages compared to the single-PMT optical modules which have been traditionally used in neutrino telescopes, including a larger photocathode area which is equivalent to three 10-inch photomultipliers. In addition, the multi-PMT approach allows for a high resolution, good positioning and timing calibration. The integration of the optical modules follows a strict protocol and a standardised procedure. It takes place in parallel at eight different integration sites in the labs of the collaboration. In this way, it is possible to reach a significant production rate of more than 100 well-qualified modules per month. In this proceeding, we present details of the technology of the KM3NeT optical module and the integration process.
Apraxie
Authors: Randerath Jennifer , Hermsdörfer Joachim
Published: March 2023

Das schnelle Erkennen der facettenreichen und durch Störung der
motorisch-kognitiven Fähigkeiten gekennzeichnete
Gliedmaßenapraxie gestaltet sich häufig schwierig. Oft ist sie
durch andere Beeinträchtigungen wie Aphasie, Gedächtnisprobleme
oder Hemiplegie verdeckt. Der Artikel gibt Hinweise zur Diagnostik und zu
therapeutischen Ansätzen.
A Significant Role of Nontypeable Haemophilus influenzae in Acute Otitis Media in Bulgarian Children
Authors: Alexandrova Alexandra Sashova , Hristova Preslava , Hitkova Hristina , Gergova Raina Tsvetanova
Published: March 2023

Objective We conducted a study on Haemophilus influenzae isolates recovered from children with acute otitis media (AOM). We aimed to establish the distribution of noncapsulated (also known as nontypeable Haemophilus influenzae [NTHi]) and encapsulated H. influenzae in the study population, and the antimicrobial susceptibilities of the isolates.

Methods We collected 113 nasopharyngeal swabs and 91 middle ear fluids/otorrhea specimens from patients up to 9 years of age with AOM. Of these, 26.1% (n = 53) were culture-positive for H. influenzae. Only one episode of AOM was included per patient. Conventional tests and rapid panel Neisseria/Haemophilus panel were used for the identification of the isolates. Detection of encapsulated and noncapsulated strains was done by polymerase chain reaction (PCR) for bexA gene. PCR-serotyping was performed for capsule types: “a” and “f.” Biotypes were assigned based on the indole, urease, and ornithine decarboxylase activity. Susceptibility testing was performed according to the criteria of European Committee on Antimicrobial Susceptibility Testing (EUCAST).

Results Capsule determination showed that 96.2% of H. influenzae isolates responsible for “mild” and “severe” AOM cases in children were NTHi. Biotype I was predominantly associated with AOM isolates. Capsule types “a” and “c” were found in two isolates. Antibiotic resistance was found in 39.6% of the isolates. The highest resistance rate was for trimethoprim-sulfamethoxazole (37.7%). About 20.7% of isolates were ampicillin-resistant: 5.6% expressed a β-lactamase, and 15.1% had a β–lactamase-negative ampicillin-resistant phenotype.

Conclusion The current prevalence rates of nonsusceptible H. influenzae to ampicillin appear to be low among AOM. NTHi is an emergent pathogen in AOM cases. Ongoing observations are needed about how NTHi colonizes, survives, and evolves into a leading causative agent of H. influenzae diseases.
The Post–Venous Thromboembolism Functional Status Scale: From Call to Action to Application in Research, Extension to COVID-19 Patients, and Its Use in Clinical Practice
Authors: de Jong Cindy M. M. , Boon Gudula J.A.M. , Le Y. N. Jenny , Barco Stefano , Siegerink Bob , Klok Frederikus A.
Published: March 2023

A broad spectrum of long-term sequelae may be present in venous thromboembolism (VTE) survivors, affecting their quality of life and functioning. To monitor recovery and improve the prognosis of patients with persistent functional limitations, the development of a new outcome measure that could better capture the consequences of VTE was an unmet need. Starting as a call to action, the Post-VTE Functional Status (PVFS) scale was developed to meet this need. The PVFS scale is an easy-to-use clinical tool to measure and quantify functional outcomes after VTE by focusing on key aspects of daily life. As the scale was considered useful in coronavirus disease 2019 (COVID-19) patients as well, the Post-COVID-19 Functional Status (PCFS) scale was introduced early in the pandemic after slight adaptation. The scale has been well incorporated into both the VTE and COVID-19 research communities, contributing to the shift of focus toward patient-relevant functional outcomes. Psychometric properties have been evaluated, mainly for the PCFS scale but recently also for the PVFS scale, including validation studies of translations, showing adequate validity and reliability. In addition to serving as outcome measure in studies, guidelines and position papers recommend using the PVFS and PCFS scale in clinical practice. As broad use of the PVFS and PCFS scale in clinical practice is valuable to capture what matters most to patients, widespread implementation is a crucial next step. In this review, we discuss the development of the PVFS scale and introduction in VTE and COVID-19 care, the incorporation of the scale in research, and its application in clinical practice.
A Novel NR5A1 Mutation in a Thai Boy with 46, XY DSD
Authors: Wacharasindhu Suttipong , Ittiwut Chupong , Ittiwut Rungnapa , Aroonparkmongkol Suphab , Suphapeetiporn Kanya
Published: March 2023

Disorders of sex development (DSD) can be classified as 46,XX DSD, 46,XY DSD, and sex chromosome DSD. Several underlying causes including associated genes have been reported. Steroidogenic factor-1 is encoded by the NR5A1 gene, a crucial regulator of steroidogenesis in the growth of the adrenal and gonadal tissues. It has been discovered to be responsible for 10 to 20% of 46, XY DSD cases. Here, we described a 2-month-old infant who had ambiguous genitalia and 46, XY. Using whole exome sequencing followed by polymerase chain reaction–Sanger sequencing, a novel heterozygous nonsense c.1249C > T (p.Gln417Ter) variant in the NR5A1 gene was identified. It is present in his mother but absent in his father and maternal aunt and uncle. At the age of 7 months, the patient received a monthly intramuscular injection of low-dose testosterone for 3 months in a row. His penile length and diameter increased from 1.8 to 3 cm and from 0.8 to 1.3 cm, respectively. The patient also had normal adrenal reserve function by adrenocorticotropic hormone stimulation test. This study identified a novel causative p.Q417X (c.1249C > T) variant in NR5A1 causing 46,XY DSD in a Thai boy which is inherited from his unaffected mother.
Diversity and pluralism in Arab media education curricula: an analytical study in light of UNESCO standards
Authors: Mansoor Hasan M. H.
Published: March 2023

Prior research looking at Arab experiences in media education, despite its importance, did not provide a comprehensive evaluation of the curricula and study plans in Arab media colleges and departments but rather treated media education in a narrow and partial way. Therefore, this study fills this research gap by analysing the curricula of 21 media colleges, departments and institutes in 10 Arab countries from a perspective related to pressing issues of the Arab world, namely, the issues of diversity, pluralism, rights and freedoms. Three levels of content analysis were adopted to evaluate media education in the Middle East and North Africa—specifically, the learning objectives for managing diversity and differences based on UNESCO’s Media and Information Literacy Curriculum for Educators and Learners. The results showed that 33.2% (79 out of 238) of the total number of learning objectives in the UNESCO curriculum were specific to the skills of managing diversity. The study classified them into five main areas: promoting human rights, equality, pluralism, the culture of dialogue, and the commitment to ethics. Emphasis on adherence to media ethics was the most evident in all of the Arab academic plans, followed by, to a lesser extent, the emphasis on promoting the culture of dialogue, peace, and understanding, and finally promoting human rights. The weaknesses were represented in the lack of clarity on the items related to pluralism, democratic practice, equality, and the empowerment of women. The paper concludes with a discussion of the importance of adopting deeper methods of analysis to evaluate the items on enhancing diversity management in all Arab education curricula, in addition to the importance of establishing a practical discussion among decision-makers and experts to integrate new media education into the curricula of media students in line with advanced international experiences and take into account the notion of cultural privacy.
Socioeconomic status and social capital as predictors of happiness: evidence and gender differences
Authors: Adedeji Adekunle , Olonisakin Tosin Tunrayo , Buchcik Johanna , Idemudia Erhabor S.
Published: March 2023

Understanding socioeconomic status (SES) and social capital as predictors of life outcomes has remained central to humanitarian, health and social research. This current study explores how socioeconomic status and social capital (community solidarity, locus of control and generalised trust) predict happiness among a sample of South African adults. Possible gender differences were also considered. Cross-sectional data from (n = 1049) South Africans on SES, social capital, happiness and sociodemographic characteristics were collected using an online questionnaire between January 2021 and September 2021. A correlation matrix was calculated to explore bivariate associations between the variables. Hierarchical regression analysis was conducted to examine the predictive influence of SES and social capital indices on happiness and the gender differential in these relationships. SES and all social capital variables were significantly correlated with happiness. The model, including SES and social capital, accounted for 25% of the variance in happiness. Gender differences were found regarding the relationship between SES and all social capital variables (except locus of control) and happiness. The results confirm that efforts to facilitate individual social capital correspond to greater happiness among South Africans. Furthermore, it highlights the need for further empirical exploration of social predictors of life outcomes. The current analysis provides a framework for developing and implementing policies that promote happiness and other life outcomes.
On the strong solution of 3D non-isothermal Navier–Stokes–Cahn–Hilliard equations
Authors: Zhao Xiaopeng
Published: March 2023

In this paper, we consider the global existence of strong solutions of a thermodynamically consistent diffuse interface model describing two-phase flows of incompressible fluids in a non-isothermal setting. In the diffuse interface model, the evolution of the velocity u is ruled by the Navier–Stokes system, while the order parameter φ representing the difference of the fluid concentration of the two fluids is assumed to satisfy a convective Cahn–Hilliard equation. The effects of the temperature are prescribed by a suitable form of heat equation. By using a refined pure energy method, we prove the existence of the global strong solution by assuming that ‖u0‖H32+‖φ0‖H42+‖θ0‖H32+‖φ02−1‖L22+‖θ0‖L1 is sufficiently small, and higher order derivatives can be arbitrarily large.
Research on a bimetallic-sensitized FBG temperature sensor
Authors: Cai Yin , Zhang BingBing , Wang JingYuan , Teng YunTian , Liu RuiFeng , Yu Cheng
Published: March 2023

Temperature measurement is of great significance for research in the health monitoring of large structures and earthquake precursors. Against the frequently reported low sensitivity of fiber Bragg grating (FBG) temperature sensors, a bimetallic-sensitized FBG temperature sensor was proposed. The sensitization structure of the FBG temperature sensor was designed, and the sensor sensitivity was analyzed; the lengths and materials of the substrate and strain transfer beam were analyzed theoretically; 7075 aluminum and 4J36 invar were chosen as bimetallic materials, and the ratio of the substrate length to the sensing fiber length was determined. The structural parameters were optimized; the real sensor was developed, and its performance was tested. The results suggested that the sensitivity of the FBG temperature sensor was 50.2 pm/°C, about five times than that of a bare FBG sensor, and its linearity was more than 0.99. The findings offer a reference for developing sensors of the same type and further improving the sensitivity of the FBG temperature sensors.
Classification of degenerate non-homogeneous Hamiltonian operators
Authors: Dell’Atti Marta , Vergallo Pierandrea
Published: March 2023

We investigate non-homogeneous Hamiltonian operators composed of a first order Dubrovin–Novikov operator and an ultralocal one. The study of such operators turns out to be fundamental for the inverted system of equations associated with a class of Hamiltonian scalar equations. Often, the involved operators are degenerate in the first order term. For this reason, a complete classification of the operators with a degenerate leading coefficient in systems with two and three components is presented.
Magnetoplasmonics in confined geometries: Current challenges and future opportunities
Authors: Maccaferri Nicolò , Gabbani Alessio , Pineider Francesco , Kaihara Terunori , Tapani Tlek , Vavassori Paolo
Published: March 2023

Plasmonics represents a unique approach to confine and enhance electromagnetic radiation well below the diffraction limit, bringing a huge potential for novel applications, for instance, in energy harvesting, optoelectronics, and nanoscale biochemistry. To achieve novel functionalities, the combination of plasmonic properties with other material functions has become increasingly attractive. In this Perspective, we review the current state of the art, challenges, and future opportunities within the field of magnetoplasmonics in confined geometries, an emerging area aiming to merge magnetism and plasmonics to either control localized plasmons, confined electromagnetic-induced collective electronic excitations, using magnetic properties, or vice versa. We begin by highlighting the cornerstones of the history and principles of this research field. We then provide our vision of its future development by showcasing raising research directions in hybrid magnetoplasmonic systems to overcome radiation losses and novel materials for magnetoplasmonics, such as transparent conductive oxides and hyperbolic metamaterials. Finally, we provide an overview of recent developments in plasmon-driven magnetization dynamics, nanoscale opto-magnetism, and acousto-magnetoplasmonics. We conclude by giving our personal vision of the future of this thriving research field.
Low-frequency unsteadiness of recompression shock structures in the diffuser of supersonic ejectors
Authors: Gupta Pradeep , Kumar Pramod , Rao Srisha M. V.
Published: March 2023

Supersonic ejectors are passive gasdynamic devices that compress a low-pressure fluid by utilizing the kinetic energy of a high-pressure fluid in a variable area duct. The ejector consists of a primary supersonic nozzle in a mixing duct where the secondary flow is entrained and mixed. The mixed flow can undergo a series of recompression shocks resulting in a subsonic flow in the diverging portion to aid pressure recovery. Recompression shocks usually lead to unsteady shock boundary layer interactions. The performance of the ejector is influenced by shear layers, shock and expansion waves, and their mutual interactions. While existing literature has extensively dealt with mixing of the primary and secondary flows, the unsteadiness in flow resulting from recompression shocks has been seldom investigated. Fluctuations in pressure due to the unsteadiness of the shock often lead structural fatigue issues. This paper reports a detailed investigation on low-frequency unsteadiness of recompression shock using high-speed schlieren images and dynamic pressure measurements. Modal analyses using proper orthogonal decomposition and dynamic mode decomposition techniques are used to determine the dominant spatial modes and associated frequencies. Multimodal frequencies ranging between 80 and 300 Hz are observed. These findings are further corroborated by Fourier and wavelet transformations of the experimentally measured wall static pressure signals. Subsequently, scaling parameter is established for the dominant frequencies based on flow velocities upstream of the shock and the distance between two consecutive shocks. This results in a unique scaling frequency of 4.58% ± 18%, for the recompression shock independent of operating conditions.
Surface physical cues mediate the uptake of foreign particles by cancer cells
Authors: Tischenko Katerina , Brill-Karniely Yifat , Steinberg Eliana , Segev-Yekutiel Hadas , Benny Ofra
Published: March 2023

Cancer phenotypes are often associated with changes in the mechanical states of cells and their microenvironments. Numerous studies have established correlations between cancer cell malignancy and cell deformability at the single-cell level. The mechanical deformation of cells is required for the internalization of large colloidal particles. Compared to normal epithelial cells, cancer cells show higher capacities to distort their shapes during the engulfment of external particles, thus performing phagocytic-like processes more efficiently. This link between cell deformability and particle uptake suggests that the cell's adherence state may affect this particle uptake, as cells become stiffer when plated on a more rigid substrate and vice versa. Based on this, we hypothesized that cancer cells of the same origin, which are subjected to external mechanical cues through attachment to surfaces with varying rigidities, may express different capacities to uptake foreign particles. The effects of substrate rigidity on cancer cell uptake of inert particles (0.8 and 2.4 μm) were examined using surfaces with physiologically relevant rigidities (from 0.5 to 64 kPa). Our data demonstrate a wave-like (“meandering”) dependence of cell uptake on the rigidity of the culture substrate explained by a superposition of opposing physical and biological effects. The uptake patterns were inversely correlated with the expression of phosphorylated paxillin, indicating that the initial passive particle absorbance is the primary limiting step toward complete uptake. Overall, our findings may provide a foundation for mechanical rationalization of particle uptake design.
Intercalating-induced second-harmonic generation in centrosymmetric multilayer graphene
Authors: Zeng Ganying , Fang Zhenyu , Qin Chengbing , Xiao Liantuan , Jia Suotang
Published: March 2023

Second-harmonic generation (SHG) is a nonlinear optical process, where two incident photons coherently combine into one photon with double the energy, which is important for laser frequency conversion. Graphene has huge potential in various on-chip optical applications including laser sources, waveguide structures, and detection-sensitive units. However, efficient SHG is commonly present in systems with broken inversion symmetry but absent from centrosymmetric structures such as graphene. The study of graphene SHG signal has gradually become a hot research topic. In our work, H2SO4-intercalation tunable method was developed to tune the lattice distortion of multilayer graphene and lead to charge transfer from graphene layers to H2SO4 molecules. Thus, noncentrosymmetric electric dipoles can be acquired and enhance SHG response. Furthermore, the change of SHG is reversible after deintercalation, because the lattice distortion can be restored. Our research on the intercalating-induced SHG effect may lead to a better design of graphene-based nonlinear optical devices in the future.
Higher-order Rayleigh-quotient gradient effect on electron correlations
Authors: Sarwono Yanoar Pribadi , Zhang Rui-Qin
Published: March 2023

The incomplete understanding of electron correlation is still profound due to the lack of exact solutions of the Schrödinger equation of many electron systems. In this work, we present the correlation-induced changes in the calculated many-electron systems beyond the standard residual. To locate the minimum of the Rayleigh quotient, each iteration is to seek the lowest eigenpairs in a subspace spanned by the current wave function and its gradient of the Rayleigh-quotient as well as the upcoming higher-order residual. Consequently, as the upcoming errors can be introduced and circumvented with the search in the higher-order residual, a concomitant improved performance in terms of number of iterations, convergence rate, and total elapsed time is very significant. The correlation energy components obtained with the original residual are corrected with the higher-order residual application, satisfying the correlation virial theorem with much improved accuracy. The comparison with the original residual, the higher-order residual significantly improves the electron binding, favoring the localization of electrons’ distribution, revealed with the increasing peak of the distribution and correlation function and the reduced interelectron distance and its angle.
Effect of rotation on the suspension of phototactic bioconvection
Authors: Kumar Sandeep
Published: March 2023

In this article, we examine the effect of rotation on the suspension of the phototactic bioconvection model. Around a vertical axis, the suspension is rotated at a uniform angular velocity. During the study, two distinct combinations of the upper boundary conditions were considered. In order to solve the eigenvalue problem, the Newton–Raphson–Kantorovich finite difference method of order four is used. Linear analysis of the basic state is performed using neutral curves. We found that rotation has stabilizing effects on the system. According to observations, rigid boundaries should be preferred over other types of boundaries for preventing convection as they stabilize it more quickly. The results demonstrate a change in the most unstable mode from an overstable to a stationary state for particular parameters in response to a variation in the Taylor number. The rigid upper surface case often exhibits oscillatory instabilities at Taylor number increments. The impacts of the various other factors on the system's instability are discussed in detail for both upper boundaries.
Empirical test of the Kelvin relation in a Bi2Te3 thermopile
Authors: Panthi Hari Prasad , Dhawan Ruchika , Edwards Hal , Lee Mark
Published: March 2023

The Kelvin relation (KR) connecting the Peltier coefficient Π, the thermopower α, and the absolute temperature T via Π = αT is a cornerstone of thermoelectric (TE) physics. It is also a widely recognized example of an Onsager reciprocal relation, a foundational principle in nonequilibrium irreversible thermodynamics. While the KR is routinely invoked to understand TE systems, it has surprisingly little rigorous empirical verification. Accurate experimental tests of the KR are complicated by several factors, including non-Peltier heat flows such as Joule heating or Fourier thermal conduction, uncharacterized thermal contact impedances, and the need for Peltier and thermopower effects to be measured on the same thermopile at the same temperatures. Most empirical assessments of the KR have either made questionable simplifications or been limited in accuracy to several percent. Here, we present a test of the KR that is free of the difficulties of prior experiments and relies only on conventional voltage, current, and temperature measurements, so that it could be performed on any thermopile. Conducting the test on a Bi2Te3 thermopile, the empirical ratio Π/α is found to equal T within a relative deviation < 0.5% for T in the range of 320–340 K. This result is quantitatively consistent with the KR and justifies the use of the KR in TE applications to reasonably high accuracy.
Light competition is the key factor determining spatio-temporal variability in legume proportion within Marandu palisadegrass–forage peanut mixed pastures
Authors: Spasiani Paola Palauro , Homem Bruno Grossi Costa , Lima Italo Braz Gonçalves de , Guimarães Bianca Costa , Medeiros Elias Silva de , Muir James Pierre , Oliveira Marcelo Silva de , Boddey Robert Michael , Casagrande Daniel Rume
Published: March 2023

Context Understanding ecology in grass–legume pastures can help support strategies aimed at maintaining canopy stability in terms of botanical composition. Aims This 2-year study evaluated spatial variability, focusing on plant structural characteristics in a Marandu palisadegrass [Urochloa brizantha (Hochst. Ex A. Rich.) R.D. Webster cv. Marandu]–forage peanut (Arachis pintoi Krapov. and W.C. Greg. cv. BRS Mandobi) mixed canopy under grazing in continuous stocking management. Methods The pasture was managed with canopy height of 20–25 cm. The experimental area had a permanent sample grid containing 50 pre-established and georeferenced plots. Principal component analysis was performed, and spatial dependence structure of the first principal component and structural variables were separately characterised by geostatistical analysis. Key results There was spatial dependence of the structural characteristics, with marked spatial heterogeneity in the distribution of all variables. Taller grass canopies caused competition for light between species, reducing legume contribution and inducing more erect forage peanut growth habit. Conversely, in areas with lower grass canopy height, forage peanut botanical composition increased to up to 70%, as it propagated more effectively by stoloniferous propagation. Conclusions The canopy structure spatial variability of a Marandu palisadegrass–forage peanut mixed pasture determines the overall average pasture grass/legume proportion. In regions with taller canopies, Marandu palisadegrass was favoured, while in areas with shorter canopy, forage peanut proportion was promoted. Satisfactory legume proportions can be reached in the canopy despite areas with reduced legume contribution. Implications Our findings using geostatistical techniques facilitate the development of useful and innovative tools allowing better comprehension for the management of mixed pastures.
A dynamical model of
C. elegans
thermal preference reveals independent excitatory and inhibitory learning pathways
Authors: Roman Ahmed , Palanski Konstantine , Nemenman Ilya , Ryu William S.
Published: March 2023

Caenorhabditis elegans
is capable of learning and remembering behaviorally relevant cues such as smells, tastes, and temperature. This is an example of associative learning, a process in which behavior is modified by making associations between various stimuli. Since the mathematical theory of conditioning does not account for some of its salient aspects, such as spontaneous recovery of extinguished associations, accurate modeling of behavior of real animals during conditioning has turned out difficult. Here, we do this in the context of the dynamics of the thermal preference of
C. elegans
. We quantify
C. elegans
thermotaxis in response to various conditioning temperatures, starvation durations, and genetic perturbations using a high-resolution microfluidic droplet assay. We model these data comprehensively, within a biologically interpretable, multi-modal framework. We find that the strength of the thermal preference is composed of two independent, genetically separable contributions and requires a model with at least four dynamical variables. One pathway positively associates the experienced temperature independently of food and the other negatively associates with the temperature when food is absent. The multidimensional structure of the association strength provides an explanation for the apparent classical temperature–food association of
C. elegans
thermal preference and a number of longstanding questions in animal learning, including spontaneous recovery, asymmetric response to appetitive vs. aversive cues, latent inhibition, and generalization among similar cues.
WDFY4 deficiency in NOD mice ameliorates autoimmune diabetes and insulitis
Authors: Ferris Stephen T. , Liu Tiantian , Chen Jing , Ohara Ray A. , Ou Feiya , Wu Renee , Kim Sunkyung , Murphy Theresa L. , Murphy Kenneth M.
Published: March 2023

The events that initiate autoimmune diabetes in nonobese diabetic (NOD) mice remain poorly understood. CD4
+
and CD8
+
T cells are both required to develop disease, but their relative roles in initiating disease are unclear. To test whether CD4
+
T cell infiltration into islets requires damage to β cells induced by autoreactive CD8
+
T cells, we inactivated
Wdfy4
in nonobese diabetic (NOD) mice (NOD.
Wdfy4
−/−-
) using CRISPR/Cas9 targeting to eliminate cross-presentation by type 1 conventional dendritic cells (cDC1s). Similar to C57BL/6
Wdfy4
−/−
mice, cDC1 in NOD.
Wdfy4
−/−
mice are unable to cross-present cell-associated antigens to prime CD8
+
T cells, while cDC1 from heterozygous NOD.
Wdfy4
+/−
mice cross-present normally. Further, NOD.
Wdfy4
−/−
mice fail to develop diabetes while heterozygous NOD.
Wdfy4
+/−
mice develop diabetes similarly to wild-type NOD mice. NOD.
Wdfy4
−/−
mice remain capable of processing and presenting major histocompatibility complex class II (MHC-II)-restricted autoantigens and can activate β cell-specific CD4
+
T cells in lymph nodes. However, disease in these mice does not progress beyond peri-islet inflammation. These results indicate that the priming of autoreactive CD8
+
T cells in NOD mice requires cross-presentation by cDC1. Further, autoreactive CD8
+
T cells appear to be required not only to develop diabetes, but to recruit autoreactive CD4
+
T cells into islets of NOD mice, perhaps in response to progressive β cell damage.
Zariski density of crystalline points
Authors: Böckle Gebhard , Iyengar Ashwin , Paškūnas Vytautas
Published: March 2023

We show that crystalline points are Zariski dense in the deformation space of a representation of the absolute Galois group of a
p
-adic field. We also show that these points are dense in the subspace parameterizing deformations with the determinant equal to a fixed crystalline character. Our proof is purely local and works for all
p
-adic fields and all residual Galois representations.
An astonishing regularity in student learning rate
Authors: Koedinger Kenneth R. , Carvalho Paulo F. , Liu Ran , McLaughlin Elizabeth A.
Published: March 2023

Leveraging a scientific infrastructure for exploring how students learn, we have developed cognitive and statistical models of skill acquisition and used them to understand fundamental similarities and differences across learners. Our primary question was why do some students learn faster than others? Or, do they? We model data from student performance on groups of tasks that assess the same skill component and that provide follow-up instruction on student errors. Our models estimate, for both students and skills, initial correctness and learning rate, that is, the increase in correctness after each practice opportunity. We applied our models to 1.3 million observations across 27 datasets of student interactions with online practice systems in the context of elementary to college courses in math, science, and language. Despite the availability of up-front verbal instruction, like lectures and readings, students demonstrate modest initial prepractice performance, at about 65% accuracy. Despite being in the same course, students’ initial performance varies substantially from about 55% correct for those in the lower half to 75% for those in the upper half. In contrast, and much to our surprise, we found students to be astonishingly similar in estimated learning rate, typically increasing by about 0.1 log odds or 2.5% in accuracy per opportunity. These findings pose a challenge for theories of learning to explain the odd combination of large variation in student initial performance and striking regularity in student learning rate.
Impacts of Nb on grain refinement in a simulated coarse-grained-heat-affected-zone of ultra-high-strength steels
Authors: Wang Libo , Hu Chengyang , Wan Xiangliang , Zhou Songbo , Wei Ran , Zhu Chengyi , Li Guangqiang , Wu Kaiming
Published: March 2023

The impact of Nb contents on grain refinement in a simulated coarse-grained heated-affected zone (CGHAZ) in steels was investigated. The austenite grain grew in multiple directions and then impinged against each other during the α→γ transformation. Subsequently, austenite grains coarsened via the coalescence of small grains and boundary migration. With the increased Nb content, the austenite in CGHAZ became coarser due to the decreased quantity and increased size of Nb precipitates. Furthermore, the austenite decomposed into bainite during the cooling process. Compared with the low-Nb specimen, the crystallographic grain size in CGHAZ of high-Nb specimen is slightly coarser, relating to the coarser prior austenite grain. However, higher Nb content delays the bainite transformation start temperature, leading to multiple variants selection of bainite, increasing the refinement ratio.
Final report, ongoing key comparison BIPM.QM-K1, ozone at ambient level, comparison with NIST, July 2022
Authors: Viallon Joële , Idrees Faraz , Moussay Philippe , Wielgosz Robert , Norris Jim , Trask Peter
Published: March 2023

Main text

As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of the United States maintained by the National Institute for Standards and Technology (NIST) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount fraction range of 0 nmol mol−1 to 500 nmol mol−1.

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

The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Trajectories of electric charges passing through an ideal solenoid and a thin conducting pipe arranged coaxially
Authors: Abdullah Mikrajuddin
Published: March 2023

We discuss the effect of fields produced by a coaxially arranged ideal solenoid and thin conducting pipe on electric charge trajectories. The electric charges released from positions outside the solenoid/pipe are trapped by electric and magnetic fields. The combination of forces generated by the two types of field results in ‘spider web-like’ trajectories. We also discuss the concepts of the mass spectrometer and the isotope discriminator, although we do not go into detail about how to generate ions and detect them. This topic may be of interest to undergraduate students since it only uses basic physics and mathematics skills and sounds innovative.
Developing digital twins of multi-camera metrology systems in Blender
Authors: Pottier C , Petzing J , Eghtedari F , Lohse N , Kinnell P
Published: March 2023

Blender is an open-source three-dimensional animation software, which can be used as a simulation tool in metrology, to build numerical models that can be used in the design and optimisation of camera-based measurement systems. In this work, the relevance of using Blender to model camera-based measurement systems was explored. Two experiments were conducted in real-world and Blender modelled environments, one using individual cameras for a simple measurement task, the other considering multi-camera position optimisation. The objective was to verify whether the virtual cameras created in Blender can perceive and measure objects in the same manner as the real cameras in an equivalent environment. The results demonstrate that in its native modelling format Blender satisfies the optical metrology characteristics of measurement, but the correlation between Blender output and real-world results is highly sensitive to initial modelling parameters such as illumination intensity, camera definitions and object surface texture.
Open-source electronics ecosystem for optical atomic clocks
Authors: Morzyński Piotr , Bilicki Sławomir , Bober Marcin , Ledziński Adam , Witkowski Marcin , Zarei Mehrdad , Zawada Michał
Published: March 2023

We present an open-source hardware and software ecosystem for optical atomic clocks. We provide PCB schematics and fabrication files for manufacturing the most important electronic systems together with the required software. The boards are designed for an active bad-cavity superradiant strontium clock and a passive optical lattice strontium clock, but they can be easily adapted to other atomic species’ optical atomic clocks or ultra-cold atoms’ systems like magneto-optical traps or Bose–Einstein condensate setups.
Analyzing the effectiveness of MEMS sensor and IoT in predicting wave height using machine learning models
Authors: Mishra Jai Prakash , Singh Kulwant , Chaudhary Himanshu
Published: March 2023

Wave height is a critical consideration in the planning and execution of maritime projects. Wave height forecasting methods include numerical and machine learning (ML) techniques. The traditional process involves using numerical wave prediction models, which are very successful but are highly complex as they require adequate information on nonlinear wind–wave and wave–wave interactions, such as the wave energy-balance equation. In contrast, ML techniques can predict wave height without prior knowledge of the above-mentioned complex interactions. This research aims to predict wave height using micro-electromechanical systems (MEMS), internet of things (IoTs), and ML-based approaches. A floating buoy is developed using a MEMS inertial measurement unit and an IoT microcontroller. An experiment is conducted in which the developed buoy is subjected to different wave heights in real time. The changes in three-axis acceleration and three-axis gyroscope signals are acquired by a computer via IoT. These signals are analyzed using ML-based classification models to accurately predict wave height. The obtained validation accuracy of the ML models K-NN (K-nearest neighbor), support vector machine, and the bagged tree is 0.9906, 0.9368, and 0.9887 respectively, which indicates that MEMS and IoT can be used to accurately classify and predict wave heights in real-time.
Five-degrees-of-freedom error motion measurement method of precision rotary table based on BMPES
Authors: Shao Meng , Shao Xianlei , Li Xinran , Wang Sainan , Li Songhua , Chen Zhe , An Dong
Published: March 2023

It is essential to obtain the five-degrees-of-freedom (5-DOF) error motion of a rotary table to reconstructthe real trajectory of the rotating shaft, but there are many error coupling problems when measuring the error motion of a rotary table. In order to improve the measurement accuracy of the 5-DOF error motion of the rotary table, a method of measuring the error motions based on bidirectional multi-point error separation (BMPES) is proposed. First, by analyzing the motion characteristics of the rotary table with multiple degrees of freedom error during the rotation, a detection system with a double-layer structure probe arrangement is designed. Then, the three-point method is used in the radial direction to separate the roundness error of the measuring disk, which improves the measurement accuracy of radial error. Finally, the coupling relationship between the mixing errors collected by the axial probes is researched, and a face-four-point error separation method is proposed, which can separate the flatness error of the lower surface of the measuring disk and complete the decoupling of the tilt error and the axial runout error. Simulation results show that for the measurement of radial, tilt and axial errors, the measurement errors of the BMPES method proposed in this paper are reduced by 97.89%, 68.40% and 99.99%, respectively, compared with the five-point method, and when eccentricity errors exist, the measurement errors of the radial and tilt errors are reduced by 99.06% and 85.67%, which verifies that the method can accurately obtain the 5-DOF motion of the rotary table errors.
Lie group valued Koopman eigenfunctions
Authors: Das Suddhasattwa
Published: March 2023

Every continuous-time flow on a topological space has associated to it a Koopman operator, which operates by time-shifts on various spaces of functions, such as C

r
, L
2, or functions of bounded variation. An eigenfunction of the vector field (and thus for the Koopman operator) can be viewed as an S
1-valued function, which also plays the role of a semiconjugacy to a rigid rotation on S
1. This notion of Koopman eigenfunctions will be generalized to Lie-group valued eigenfunctions, and we will discuss the dynamical aspects of these functions. One of the tools that will be developed to aid the discussion, is a concept of exterior derivative for Lie group valued functions, which generalizes the notion of the differential

d

f

of a real valued function f. The extended notion of Koopman eigenfunctions utilizes a geometric property of usual eigenfunctions. We show that the generalization in a geometric sense can be used to reveal fundamental properties of usual Koopman eigenfunctions, such as their behaviour under time-rescaling, and as submersions.