cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Analysis of the directionality on periodic materials
Creators: name: Guarín-Zapata, Nicolás
name: Valencia, Camilo
name: Gómez, Juan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences
subject: 74J05, 74S05, 78A48,

description: There is an increasing interest in the study of metamaterials and periodic materials across disciplines. These are anisotropic and their properties present directionality. For example, the wave speed depends on the propagation direction. Furthermore, they are heterogeneous, and their directionality depends on their spectra. Common approaches to describe anisotropy have been used in the large-wavelength approximation corresponding to static properties. Here we present an anisotropy measure based on the dynamic behavior. It receives dispersion surfaces from Bloch analyses and outputs a curve/surface with bulk directionality encoded on it. We present results for elastodynamics, but it is applicable to other phenomena.
description: 22 pages, 15 figures. Mechanics of Advanced Materials and Structures (2023)
La prima infrastruttura di data management per le nanoscienze
Creators: name: Aversa, Rossella
name: Cozzini, Stefano
Publisher: name: Consortium GARR
Year: 2018
Subjects: Data Repository
Metadati
Nanoscienze
SEM
Reti neurali

description: In questo articolo presentiamo la prima infrastruttura di data management per le nanoscienze. L’infrastruttura, denominata IDRP (Information and Data management Repository Platform), è stata sviluppata dal CNR-IOM (Istituto di Officina dei Materiali) di Trieste all’interno di NFFA-EUROPE (Nanoscience Foundries & Fine Analysis). Questo progetto europeo Horizon 2020, coordinato dal CNR-IOM, coinvolge 20 partner ed ha lo scopo di fornire una infrastruttura di ricerca distribuita per la comunità di nanoscienze. La IDRP è nata con l’obiettivo di gestire ed archiviare in maniera FAIR la grande varietà di dati generati dalla strumentazione NFFA-EUROPE offrendo un accesso standardizzato.
On the Fast Magnetic Rotator Regime of Stellar Winds
Creators: name: Johnstone, C. P.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Aims: We study the acceleration of the stellar winds of rapidly rotating low mass stars and the transition between the slow magnetic rotator and fast magnetic rotator regimes. We aim to understand the properties of stellar winds in the fast magnetic rotator regime and the effects of magneto-centrifugal forces on wind speeds and mass loss rates. Methods: We extend the solar wind model of Johnstone et al. (2015b) to 1D magnetohydrodynamic (MHD) simulations of the winds of rotating stars. We test two assumptions for how to scale the wind temperature to other stars and assume the mass loss rate scales as Mdot ~ Rstar^2 OmegaStar^1.33 Mstar^-3.36, in the unsaturated regime, as estimated by Johnstone et al. (2015a). Results: For 1.0 Msun stars, the winds can be accelerated to several thousand km/s, and the effects of magneto-centrifugal forces are much weaker for lower mass stars. We find that the different assumptions for how to scale the wind temperature to other stars lead to significantly different mass loss rates for the rapid rotators. If we assume a constant temperature, the mass loss rates of solar mass stars do not saturate at rapid rotation, which we show to be inconsistent with observed rotational evolution. If we assume the wind temperatures scale positively with rotation, the mass loss rates are only influenced significantly at rotation rates above 75 OmegaSun. We suggest that models with increasing wind speed for more rapid rotators are preferable to those that assume a constant wind speed. If this conclusion is confirmed by more sophisticated wind modelling. it might provide an interesting observational constraint on the properties of stellar winds.
description: Accepted for publication in A&A. All data and codes from the paper can be downloaded from https://goo.gl/hTuEVw
$Suzaku$ and $XMM-Newton$ observations of a newly-discovered early-stage cluster merger 1E2216.0-0401 and 1E2215.7-0404
Creators: name: Akamatsu, H.
name: Gu, L.
name: Shimwell, T. W.
name: Mernier, F.
name: Mao, J.
name: Urdampilleta, I.
name: de Plaa, J.
name: Röttgering, H. J. A.
name: Kaastra, J. S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present the results of $Suzaku$ and $XMM-Newton$ X-ray observations of the cluster pair 1E2216.0-0401 and 1E2215.7-0404. We discover an X-ray bridge between the clusters. $Suzaku$ and $XMM-Newton$ observations revealed that each cluster hosts gas with moderate temperature of $kT_{1E2216.0-0401}=$4.8$\pm$0.1 keV and $kT_{1E2215.7-0404}=$5.8$\pm$0.2 keV, respectively. On the other hand, the bridge region shows a remarkably high temperature ({\it kT}=6.6$\pm$0.5 keV). Furthermore, at the position of the bridge, we detected an enhancement in the wavelet-decomposed soft-band (0.5-4.0 keV) $XMM-Newton$ image at 3 sigma significance, this is most likely due to a compression of the intracluster medium (ICM) as a consequence of the merging activity. This X-ray intensity and temperature enhancement are not consistent with those expected from a late phase, but are in agreement with the predictions by numerical simulations of an early phase merger. From the temperature jump at the location of the bridge, the Mach number is estimated to be ${\cal M}=1.4\pm0.1$, which corresponds to a shock propagation velocity of about 1570 km/s. From the shock properties, we estimate that core-passage will occur in 0.3-0.6 Gyr and that the age of the shock structure is 50--100 Myr. Based on the measured properties of the ICM at the bridge and estimation of timescales, we find indications for non-equilibrium ionization. We also discover possible diffuse radio emission located between the merging clusters. Combining the radio, X-ray, and optical image data, we speculate that the detected radio sources are most likely related to the merger event. Thus, 1E2216.0-0401 and 1E2215.7-0404 is a new example of an early phase cluster merger with remarkable characteristics.
description: 5 pages, 3 figures, accepted for publication in A&A Letters
Estimates of water partitioning in complex urban landscapes with isotope‐aided ecohydrological modelling
Creators: name: Gillefalk, Mikael
name: Tetzlaff, Doerthe
name: Marx, Christian
name: Smith, Aaron
name: Meier, Fred
name: Hinkelmann, Reinhard
name: Soulsby, Chris
Publisher: name: Technische Universität Berlin
Year: 2022
Subjects: subject: 550 Geowissenschaften
subject: ecohydrological modelling
subject: ecohydrology
subject: isotopes
subject: sealed surfaces
subject: tracers
subject: urban green spaces
subject: urban hydrology
subject: water partitioning

description: Urban green space is increasingly viewed as essential infrastructure to build resilience to climate change by retaining water in the city landscape and balancing ecohydrological partitioning into evapotranspiration for cooling and groundwater recharge. Quantifying how different vegetation types affect water partitioning is essential for future management, but paucity of data and the complex heterogeneity of urban areas make water balance estimates challenging. Here, we provide a preliminary assessment of water partitioning from different sized patches of trees and grass as well as from sealed surfaces. To do this, we used limited field observations together with an advanced, process‐based tracer‐aided ecohydrological model at a meso‐scale (5 km2) in central Berlin, Germany. Transpiration was the dominant green water flux accounting for over 50% of evapotranspiration in the modelled area. Green water fluxes were in general greater from trees compared with grass, but grass in large parks transpired more water compared with grass in small parks that were intensively used for recreation. Interception evaporation was larger for trees compared with grass, but soil water evaporation was greater for grass compared with trees. We also show that evapotranspiration from tree‐covered areas comprise almost 80% of the total evapotranspiration from the whole model domain while making up less than 30% of the surface cover. The results form an important stepping‐stone towards further upscaling over larger areas and highlights the importance of continuous high‐resolution hydrological measurements in the urban landscape, as well as the need for improvements to ecohydrological models to capture important urban processes.
An Efficient Epileptic Seizure Detection Technique using Discrete Wavelet Transform and Machine Learning Classifiers
Creators: name: Guharoy, Rabel
name: Jana, Nanda Dulal
name: Biswas, Suparna
Publisher: name: arXiv
Year: 2021
Subjects: subject: Signal Processing (eess.SP)
subject: Machine Learning (cs.LG)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: This paper presents an epilepsy detection method based on discrete wavelet transform (DWT) and Machine learning classifiers. Here DWT has been used for feature extraction as it provides a better decomposition of the signals in different frequency bands. At first, DWT has been applied to the EEG signal to extract the detail and approximate coefficients or different sub-bands. After the extraction of the coefficients, principal component analysis (PCA) has been applied on different sub-bands and then a feature level fusion technique is used to extract the important features in low dimensional feature space. Three classifiers namely: Support Vector Machine (SVM) classifier, K-Nearest-Neighbor (KNN) classifier, and Naive Bayes (NB) Classifiers have been used in the proposed work for classifying the EEG signals. The proposed method is tested on Bonn databases and provides a maximum of 100% recognition accuracy for KNN, SVM, NB classifiers.
description: Accepted in International Conference on Smart Technologies for Sustainable Development (ICSTSD2021)
A comparative study of integral and coupled approaches for modeling hydraulic exchange processes across a rippled streambed
Creators: name: Sobhi Gollo, Vahid
name: Broecker, Tabea
name: Marx, Christian
name: Lewandowski, Jörg
name: Nützmann, Gunnar
name: Hinkelmann, Reinhard
Publisher: name: Technische Universität Berlin
Year: 2022
Subjects: subject: 550 Geowissenschaften
subject: integral model
subject: coupled model
subject: groundwater–surface water interface
subject: numerical modeling
subject: Navier–Stokes equations
subject: shallow water equations

description: Although both are crucial parts of the hydrological cycle, groundwater and surface water had traditionally been addressed separately. In recent decades, considering them as a single hydrological continuum in light of their continuous interaction has become well established in the scientific community through the development of numerous measurement and experimental techniques. Nevertheless, numerical models, as necessary tools to study a wide range of scenarios and future event predictions, are still based on outdated concepts that consider groundwater and surface water separately. This study compares these “coupled models”, which result from the successive execution of a surface water model and a groundwater model, to a recently developed “integral model”. The integral model uses a single set of equations to model both groundwater and surface water simultaneously, and can account for the continuous interaction at their interface. For comparison, we investigated small-scale flow across a rippled porous streambed. Although we applied identical model domain details and flow conditions, which resulted in very similar water tables and pressure distributions, comparing the integral and coupled models yielded very dissimilar velocity values across the groundwater–surface water interface. These differences highlight the impact of continuous exchange across the interface in the integral model, which imitates such flow processes more realistically than the coupled model. A few decimeters away from the interface, modeled velocity fields are very similar. Since the integral model and the surface water component of the coupled model are both CFD-based (computational fluid dynamics), they require very similar computational resources, namely access to cluster computers. Unfortunately, replacing the surface water component of the coupled model with the widely used shallow water equations model, which indeed would reduce the computational resources required, produces inaccuracy.
Bivariate network meta-analysis for surrogate endpoint evaluation
Creators: name: Bujkiewicz, Sylwia
name: Jackson, Dan
name: Thompson, John R
name: Turner, Rebecca
name: Abrams, Keith R
name: White, Ian R
Publisher: name: arXiv
Year: 2018
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Surrogate endpoints are very important in regulatory decision-making in healthcare, in particular if they can be measured early compared to the long-term final clinical outcome and act as good predictors of clinical benefit. Bivariate meta-analysis methods can be used to evaluate surrogate endpoints and to predict the treatment effect on the final outcome from the treatment effect measured on a surrogate endpoint. However, candidate surrogate endpoints are often imperfect, and the level of association between the treatment effects on the surrogate and final outcomes may vary between treatments. This imposes a limitation on the pairwise methods which do not differentiate between the treatments. We develop bivariate network meta-analysis (bvNMA) methods which combine data on treatment effects on the surrogate and final outcomes, from trials investigating heterogeneous treatment contrasts. The bvNMA methods estimate the effects on both outcomes for all treatment contrasts individually in a single analysis. At the same time, they allow us to model the surrogacy patterns across multiple trials (different populations) within a treatment contrast and across treatment contrasts, thus enabling predictions of the treatment effect on the final outcome for a new study in a new population or investigating a new treatment. Modelling assumptions about the between-studies heterogeneity and the network consistency, and their impact on predictions, are investigated using simulated data and an illustrative example in advanced colorectal cancer. When the strength of the surrogate relationships varies across treatment contrasts, bvNMA has the advantage of identifying treatments for which surrogacy holds, thus leading to better predictions.
Unsupervised cryo-EM data clustering through adaptively constrained K-means algorithm
Creators: name: Xu, Yaofang
name: Wu, Jiayi
name: Yin, Chang-Cheng
name: Mao, Youdong
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantitative Methods (q-bio.QM)
subject: FOS: Biological sciences

description: In single-particle cryo-electron microscopy (cryo-EM), K-means clustering algorithm is widely used in unsupervised 2D classification of projection images of biological macromolecules. 3D ab initio reconstruction requires accurate unsupervised classification in order to separate molecular projections of distinct orientations. Due to background noise in single-particle images and uncertainty of molecular orientations, traditional K-means clustering algorithm may classify images into wrong classes and produce classes with a large variation in membership. Overcoming these limitations requires further development on clustering algorithms for cryo-EM data analysis. We propose a novel unsupervised data clustering method building upon the traditional K-means algorithm. By introducing an adaptive constraint term in the objective function, our algorithm not only avoids a large variation in class sizes but also produces more accurate data clustering. Applications of this approach to both simulated and experimental cryo-EM data demonstrate that our algorithm is a significantly improved alterative to the traditional K-means algorithm in single-particle cryo-EM analysis.
description: 35 pages, 14 figures
Enhancing urban runoff modelling using water stable isotopes and ages in complex catchments
Creators: name: Smith, Aaron
name: Tetzlaff, Doerthe
name: Marx, Christian
name: Soulsby, Chris
Publisher: name: Technische Universität Berlin
Year: 2023
Subjects: subject: 500 Naturwissenschaften und Mathematik::550 Geowissenschaften, Geologie::551 Geologie, Hydrologie, Meteorologie
subject: hydrological modelling
subject: urban hydrology
subject: water ages
subject: water stable isotopes

description: Increased urbanization, coupled with the projected impacts of climatic change, mandates further evaluation of the impact of urban development on water flow paths to guide sustainable land‐use planning. Though the general urbanization impacts of increased storm runoff peaks and reduced baseflows are well known; how the complex, non‐stationary interaction of the dominant water fluxes within dynamic urban water stores sustain streamflow regimes over longer periods of time is less well quantified. In particular, there is a challenge in how hydrological modelling should integrate the juxtaposition of rapid and slower flow pathways of the urban ‘karst’ landscape and different approaches need evaluation. In this context, we utilized hydrological and water stable isotope datasets within a modelling framework that combined the commonly used Hydrologic Engineering Center Hydrological Modelling System (HEC‐HMS) urban runoff model along with a simple hydrological tracer module and transit time modelling to evaluate the spatial and temporal variation of water flow paths and ages within a heavily urbanized 217 km2 catchment in Berlin, Germany. Deeper groundwater was the primary flow component in the upper reaches of the catchment within fewer urbanized regions, while the addition of wastewater effluent in the mid‐reaches of the catchment was the dominant water supply to sustain baseflow in the lower main stem stream, with additional direct storm runoff and shallow subsurface contributions in the more urbanized lower reaches. Water ages from each modelling approach mirrored flow contributions and water age mixing potential in subsurface storage; with older average water and lower young water contributions in less urbanized sub‐catchments and younger average water and higher young water contributions in more urbanized regions. The results from the first step towards more integrated tracer‐aided hydrologic modelling tools for similar peri‐urban catchments, given the potential limitations of simpler model frameworks. The results have broader implications for assessing the uncertainty in evaluating urban impacts on hydrological function under environmental change.
Measurement of the Anisotropy Power Spectrum of the Radio Synchrotron Background
Creators: name: Offringa, A. R.
name: Singal, J.
name: Heston, S.
name: Horiuchi, S.
name: Lucero, D. M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We present the first targeted measurement of the power spectrum of anisotropies of the radio synchrotron background, at 140 MHz where it is the overwhelmingly dominant photon background. This measurement is important for understanding the background level of radio sky brightness, which is dominated by steep-spectrum synchrotron radiation at frequencies below 0.5 GHz and has been measured to be significantly higher than that which can be produced by known classes of extragalactic sources and most models of Galactic halo emission. We determine the anisotropy power spectrum on scales ranging from 2 degrees to 0.2 arcminutes with LOFAR observations of two 18 square degree fields -- one centered on the Northern hemisphere coldest patch of radio sky where the Galactic contribution is smallest and one offset from that location by 15 degrees. We find that the anisotropy power is higher than that attributable to the distribution of point sources above 100 micro-Jy in flux. This level of radio anisotropy power indicates that if it results from point sources, those sources are likely at low fluxes and incredibly numerous, and likely clustered in a specific manner.
description: 8 pages, 5 figures, published in MNRAS, updated to published version and typos removed
Murray A. Marshall [24.3.1940 - 1.05.2015]: A brief mathematical obituary
Creators: name: Kuhlmann, Salma
Publisher: name: arXiv
Year: 2016
Subjects: subject: History and Overview (math.HO)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics

description: On April 22 2015, Murray Marshall was invited by Igor Klep and Victor Vinnikov to talk in the special session on "Operator Theory, Real Algebraic Geometry, and Moment Problems" that they co-organised for IWOTA 2015 in Tbilisi, Georgia, July 6--10. This invitation to an IWOTA edition was considered by the organisers as long overdue, given Marshall's important contributions to Real Algebraic Geometry in general, and to the multi-dimensional Moment Problem in particular. Marshall declined on April 27th writing: "Dear Victor, Thanks very much for the invitation. I am sorry but I must decline. The reason is that I don't enjoy traveling as much as I used to. North America or Europe is about the maximum distance I am willing to dealwith. I hope you are well. Murray." This response startled us, as Marshall has always been a grand traveler when it came to mathematics. Our fears were alas confirmed; Marshall passed away just a few days later. In July, I held a talk at that session myself on joint work with Marshall, and was asked by the editors of the proceedings volume to write this mathematical obituary.
description: 7 pages, memorial note
Satellite galaxy abundance dependency on cosmology in Magneticum simulations
Creators: name: Ragagnin, Antonio
name: Fumagalli, Alessandra
name: Castro, Tiago
name: Dolag, Klaus
name: Saro, Alexandro
name: Costanzi, Matteo
name: Bocquet, Sebastian
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Machine Learning (cs.LG)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Context: Modelling satellite galaxy abundance $N_s$ in Galaxy Clusters (GCs) is a key element in modelling the Halo Occupation Distribution (HOD), which itself is a powerful tool to connect observational studies with numerical simulations. Aims: To study the impact of cosmological parameters on satellite abundance both in cosmological simulations and in mock observations. Methods: We build an emulator (HODEmu, \url{https://github.com/aragagnin/HODEmu/}) of satellite abundance based on cosmological parameters $Ω_m, Ω_b, σ_8, h_0$ and redshift $z.$ We train our emulator using \magneticum hydrodynamic simulations that span 15 different cosmologies, each over $4$ redshift slices between $0
description: 15 pages, 13 figues, submitted to A&A
Οι μνήμες των Μικρασιατισσών από τις αλησμόνητες Πατρίδες και η συμβολή τους στα πολιτισμικά δρώμενα του Ελληνισμού: Ευτυχία Παπαγιαννοπούλου - Διδώ Σωτηρίου - Φιλιώ Χαϊδεμένου
Creators: name: Αντωνοπούλου, Ανδριάνα
Publisher: name: Πανεπιστήμιο Πελοποννήσου
Year: 2023
Subjects: subject: Ελληνο-Τουρκικός Πόλεμος, 1921-1922 -- Πρόσφυγες -- Ελλάδα
subject: Πρόσφυγες, Μικρασιάτες -- Ελλάδα -- Πνευματική ζωή
subject: Πρόσφυγες στη λογοτεχνία
subject: Παπαγιαννοπούλου, Ευτυχία, 1893-1972
subject: Σωτηρίου, Διδώ, 1909-2004
subject: Χαϊδεμένου, Φιλιώ, 1899-2007
subject: Γυναίκες -- Ελλάδα – Ιστορία – 20ός αιώνας
subject: Μνήμη
subject: Μικρά Ασία
subject: Ανατολία
subject: Καταστροφή 1922
subject: Σμύρνη
subject: Πρόσφυγες
subject: Ευτυχία Παπαγιαννοπούλου
subject: Διδώ Σωτηρίου
subject: Φιλιώ Χαϊδεμένου
subject: Asia Minor
subject: Anatolia
subject: Destruction 1922
subject: Smyrna
subject: Refugees
subject: Eftichia Papagiannopoulou
subject: Dido Sotiriou
subject: Filio Chaidemenou

description: Οι αλησμόνητες Πατρίδες ήταν ένας τόπος μεγάλης πνευματικής άνθισης και παραδόσεων, τις οποίες έφεραν στην Ελλάδα οι πρόσφυγες και επηρέασαν τον ελληνικό πολιτισμό. Οι μνήμες διατηρήθηκαν ζωντανές μέσα από την ζωή των Μικρασιατών και Μικρασιατισσών που ξεριζώθηκαν και βρέθηκαν σε έναν ξένο τόπο ανεπιθύμητοι. Η συμβολή της στιχουργού Ευτυχίας Παπαγιαννοπούλου, της δημοσιογράφου και συγγραφέως Διδώς Σωτηρίου και της συγγραφέως και ιδρύτριας μουσείου Μικρασιατικού Πολιτισμού Φιλιώ Χαϊδεμένου, είναι αδιαμφισβήτητα τεράστια στο χώρο του πολιτισμού. Μέσα από το πολύτιμο έργο και τη ζωή τους άφησαν το πολιτιστικό τους αποτύπωμα στη νεότερη Ελλάδα, κρατώντας άσβεστες τις μικρασιατικές μνήμες.
What is the Distance to the Non-Singularity of the Big Bang? CCEGA Responds
Creators: name: LOPEZ SANCHEZ, MARC
Publisher: name: Zenodo
Year: 2025
Subjects: CCEGA, Non-Singularity, Quantum Fields, Big Bang, Cosmology, Emergent Gravity
Agujeros negros, física teórica, materia oscura, energía oscura, inflación

description: This work explores the implications of the Emergent Quantum Fields and Adaptive Gravity (CCEGA) theory in addressing one of the most fundamental problems of modern cosmology: singularities. Singularities, as proposed in the standard Big Bang model, represent regions of infinite density and curvature that challenge the principles of general relativity. CCEGA provides a novel framework where the universe emerges as a dynamic property of the fundamental field , regulated by the potential . This approach eliminates singularities and offers a coherent description of the universe's evolution, from the Big Bang to its current accelerated expansion.

The paper presents a theoretical derivation of the emergent potential  and demonstrates its ability to explain the observed age of the universe, including resolving discrepancies with ancient stars like HD 140283 (the Methuselah star). Additionally, it compares predictions of the Hubble parameter and cosmic microwave background (CMB) fluctuations between the CCEGA framework and the standard ΛCDM model, highlighting key observational differences. This study offers testable predictions and pathways for further validation of the CCEGA theory, including its applications to gravitational lensing, galactic dynamics, and future observations of the CMB.
Comparison of Immersed Boundary Simulations of Heart Valve Hemodynamics against In Vitro 4D Flow MRI Data
Creators: name: Kaiser, Alexander D.
name: Schiavone, Nicole K.
name: Elkins, Christopher J.
name: McElhinney, Doff B.
name: Eaton, John K.
name: Marsden, Alison L.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Tissues and Organs (q-bio.TO)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Biological sciences
subject: FOS: Physical sciences
subject: J.3.1
subject: 76Z05 (Primary), 92C55, 92C10 (Secondary)

description: The immersed boundary (IB) method is a mathematical framework for fluid-structure interaction problems (FSI) that was originally developed to simulate flows around heart valves. Direct comparison of FSI simulations around heart valves against experimental data is challenging, however, due to the difficulty of performing robust and effective simulations, the complications of modeling a specific physical experiment, and the need to acquire experimental data that is directly comparable to simulation data. Such comparators are a necessary precursor for further formal validation studies of FSI simulations involving heart valves. In this work, we performed physical experiments of flow through a pulmonary valve in an in vitro pulse duplicator, and measured the corresponding velocity field using 4D flow MRI (4-dimensional flow magnetic resonance imaging). We constructed a computer model of this pulmonary artery setup, including modeling valve geometry and material properties via a technique called design-based elasticity, and simulated flow through it with the IB method. The simulated flow fields showed excellent qualitative agreement with experiments, excellent agreement on integral metrics, and reasonable relative error in the entire flow domain and on slices of interest. These results illustrate how to construct a computational model of a physical experiment for use as a comparator.
description: Ann Biomed Eng (2023)
Relativistic transformation of temperature and Mosengeil-Ott's antinomy
Creators: name: Mares, J. J.
name: Hubik, P.
name: Sestak, J.
name: Spicka, V.
name: Kristofik, J.
name: Stavek, J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: A not satisfactorily solved problem of relativistic transformation of temperature playing the decisive role in relativistic thermal physics and cosmology is reopened. It is shown that the origin of the so called Mosengeil-Ott's antinomy and other aligned paradoxes are related to the wrong understanding of physical meaning of temperature and application of Planck's Ansatz of Lorentz's invariance of entropy. In the contribution we have thus reintroduced and anew analyzed fundamental concepts of hotness manifold, fixed thermometric points and temperature. Finally, on the basis of phenomenological arguments the Lorentz invariance of temperature and relativistic transformations of entropy are established.
description: 9 pages
First order sensitivity analysis of symplectic eigenvalues
Creators: name: Mishra, Hemant K.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 15A18 (Primary) 15A48, 26B05, 26B27 (Secondary)

description: For every $2n \times 2n$ positive definite matrix $A$ there are $n$ positive numbers $d_1(A) \leq \ldots \leq d_n(A)$ associated with $A$ called the symplectic eigenvalues of $A.$ It is known that $d_m$ are continuous functions of $A$ but are not differentiable in general. In this paper, we show that the directional derivative of $d_m$ exists and derive its expression. We also discuss various subdifferential properties of $d_m$ such as Clarke and Michel-Penot subdifferentials.
description: 24 pages
A Trip to the Cataclysmic Binary Zoo: Detailed Follow-Up of 35 Recently-Discovered Systems
Creators: name: Thorstensen, John R.
name: Alper, Erek H.
name: Weil, Kathryn E.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We report follow-up studies of 35 recently-discovered cataclysmic variables (CVs), 32 of which were found in large, automated synoptic sky surveys. The objects were selected for observational tractability. For 34 of the objects we present mean spectra and spectroscopic orbital periods, and for one more we give an eclipse-based period. Thirty-two of the period determinations are new, and three of these refine published estimates based on superhump periods. The remaining three of our determinations confirm previously published periods. Twenty of the stars are confirmed or suspected dwarf novae with periods shorter than 3 hours, but we also find three apparent polars (AM Her stars), and six systems with P > 5 h, five of which have secondary stars visible in their spectra, from which we estimate distances when possible. The orbital period distribution of this sample is very similar to that of previously discovered CVs.
description: Accepted for Astronomical Journal. 57 pages, 17 figures
Price's law for spin fields on a Schwarzschild background
Creators: name: Ma, Siyuan
name: Zhang, Lin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 35Q75, 58K55, 58J45, 83C50, 83C60

description: In this work, we derive the globally precise late-time asymptotics for the spin-$\mathfrak{s}$ fields on a Schwarzschild background, including the scalar field $(\mathfrak{s}=0)$, the Maxwell field $(\mathfrak{s}=\pm 1)$ and the linearized gravity $(\mathfrak{s}=\pm 2)$. The conjectured Price's law in the physics literature which predicts the sharp rates of decay of the spin $s=\pm \mathfrak{s}$ components towards the future null infinity as well as in a compact region is shown. Further, we confirm the heuristic claim by Barack and Ori that the spin $+1, +2$ components have an extra power of decay at the event horizon than the conjectured Price's law. The asymptotics are derived via a unified, detailed analysis of the Teukolsky master equation that is satisfied by all these components.
description: Compatible with the published version
Density bump formation in a collisionless electrostatic shock wave in a laser-ablated plasma
Creators: name: Garasev, M. A.
name: Korytin, A. I.
name: Kocharovsky, V. V.
name: Malkov, Yu. A.
name: Murzanev, A. A.
name: Nechaev, A. A.
name: Stepanov, A. N.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The emergence of a density bump at the front of a collisionless electrostatic shock wave have been observed experimentally during the ablation of an aluminium foil by a femtosecond laser pulse. We have performed numerical simulations of the dynamics of this phenomena developing alongside the generation of a package of ion-acoustic waves, exposed to a continual flow of energetic electrons, in a collisionless plasma. We present the physical interpretation of the observed effects and show that the bump consists of transit particles, namely, the accelerated ions from the dense plasma layer, and the ions from the diluted background plasma, formed by a nanosecond laser prepulse during the ablation.
description: 5 pages, 7 figures, submitted to JETPL
Does the number of distractors of MCQs really matter?
Creators: name: Schmitz, Ulrich
name: Lerche-Sehm, Julia
name: Lindner, Marcus
name: Daubländer, Monika
Publisher: name: F1000 Research Limited
Year: 2023

description: Background:
 Traditionally, MCQs with four distractors are used for written state examinations in medical subjects in Germany. This is based on the aim of controlling the presumed significance of the guessing probability. A legal opinion on the evaluation of "court-proof" MCQs particularly emphasised it from a psychological point of view. However, the addition of a fourth distractor often leads to difficulties in the creation of MCQs. In the end, distractors are constructed that are typically chosen as the correct answer by less than 5% of the examinees. In the literature, these are referred to as non-functional distractors. In context of implementing a new written German state examination in dentistry, the significance of the number of distractors for the examination result is investigated.

 Summary of work:
 In a 100 MCQs "mock exam", one group of 30 examinees answered questions with five answer options, another group of 31 examinees the same questions with four options. The probably least appropriate fifth option had been removed by three experts. Participating subjects, volunteer candidates shortly after passing their regular oral exams, were randomly distributed between the two groups. Response characteristics were examined for each individual MCQ and for the exam in total subsequently.

 Summary of results:
 Average results achieved hardly differ between the two groups. The mean of correctly solved questions with five options is 66, SD 9, with four options 68, SD 10. Applying the usual grading system in Germany results in average grades of 3.27 and 3.26 with a similar distribution.

 Discussion and conclusion:
 Results suggest an overestimation of the influence of guessing probability. This may be because there is no normal distribution of knowledge within the groups of examinees, since all of them are students at graduation stage. It should be possible for most of them to answer the questions correctly.
 Hence, the quality of an exam consisting of MCQs seems to be independent of the number of answer options offered. Psychometric parameters are not decisively worsened, so that the effort involved in constructing a fourth distractor doesn’t seem justified.
 Further studies are needed to proof our finding in a larger cohort.
CP violating scalar Dark Matter
Creators: name: Cordero-Cid, A.
name: Hernández-Sánchez, J.
name: Keus, V.
name: King, S. F.
name: Moretti, S.
name: Rojas, D.
name: Sokołowska, D.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study an extension of the Standard Model (SM) in which two copies of the SM scalar $SU(2)$ doublet which do not acquire a Vacuum Expectation Value (VEV), and hence are \textit{inert}, are added to the scalar sector. We allow for CP-violation in the \textit{inert} sector, where the lightest \textit{inert} state is protected from decaying to SM particles through the conservation of a $Z_2$ symmetry. The lightest neutral particle from the \textit{inert} sector, which has a mixed CP-charge due to CP-violation, is hence a Dark Matter (DM) candidate. We discuss the new regions of DM relic density opened up by CP-violation, and compare our results to the CP-conserving limit and the Inert Doublet Model (IDM). We constrain the parameter space of the CP-violating model using recent results from the Large Hadron Collider (LHC) and DM direct and indirect detection experiments.
description: 42 pages, 22 figures
STACER: Assessing and monitoring medical students as simulation educator competency
Creators: name: Boleyn, Jennifer
name: Rupe, Eric
name: Ricke, Amanda
name: Noble, Ethan
name: Greengrass, Colin
name: Lustfield, Rebecca
name: Kozmenko, Valeriy
Publisher: name: F1000 Research Limited
Year: 2023

description: Physicians are life-long learners and life-long educators. Through their entire careers, they educate patients, residents, medical students, and other health care professionals. Healthcare academia has recognized this need, which resulted in developing peer-assisted teaching and learning programs. USD SSOM has created a Medical Student As Simulation Educators (MSASE) program that teaches medical students the foundational concepts of adult education and how to effectively use them in simulation-based teaching. USD SSOM has demonstrated that learners’ outcomes were similar whether they were taught by clinical faculty or by senior medical students. USD SSOM has also developed STACER (Simulation Teaching Academic Competency Evaluation Rubric) to assess MSASE-students’ teaching competencies.
Supplementary Information for Reproductive modes in populations of late-acting self-incompatible and self-compatible polyploid Ludwigia grandiflora subsp. hexapetala in western Europe
Creators: name: Stoeckel, Solenn
name: Becheler, Ronan
name: Portillo Lemus, Luis
name: Harang, Marilyne
name: Besnard, Anne-Laure
name: Lassalle, Gilles
name: Causse-Védrines, Romain
name: Michon-Coudouel, Sophie
name: Park, Daniel J.
name: Pope, Bernard J.
name: Petit, Eric J.
name: Barloy, Dominique
Publisher: name: Zenodo
Year: 2024

description: This document contains the Supplementary Information for Stoeckel et al., 2024 (https://doi.org/10.1101/2024.03.21.586104) published in Peer Community Journal, linked to the data deposited on Zenodo (https://doi.org/10.5281/zenodo.10246264, Stoeckel et al., 2023).Preprint version 4 of this article has been peer-reviewed and recommended by Peer Community In Evolutionary Biology (https://doi.org/10.24072/pci.evolbiol.100788, Alvarez, 2024).
Nonlinear model identification and spectral submanifolds for multi-degree-of-freedom mechanical vibrations
Creators: name: Szalai, Robert
name: Ehrhardt, David
name: Haller, George
Publisher: name: arXiv
Year: 2016
Subjects: subject: Dynamical Systems (math.DS)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: In a nonlinear oscillatory system, spectral submanifolds (SSMs) are the smoothest invariant manifolds tangent to linear modal subspaces of an equilibrium. Amplitude-frequency plots of the dynamics on SSMs provide the classic backbone curves sought in experimental nonlinear model identification. We develop here a methodology to compute analytically both the shape of SSMs and their corresponding backbone curves from a data-assimilating model fitted to experimental vibration signals. Using examples of both synthetic and real experimental data, we demonstrate that this approach reproduces backbone curves with high accuracy.
description: 32 pages, 4 figures
Shadows over the speed of light
Creators: name: Mares, J J
name: Hubik, P
name: Spicka, V
name: Stavek, J
name: Sestak, J
name: Kristofik, J
Publisher: name: arXiv
Year: 2016
Subjects: subject: History and Philosophy of Physics (physics.hist-ph)
subject: FOS: Physical sciences

description: In this paper, we discuss some of the consequences of the CGPM (1983) definition of meter and, in particular, we discuss giving the speed of light an exact value. It is shown that this act touches the fundamental paradigms, such as the second postulate of the special theory of relativity (STR), the c-equivalence principle and the method of time synchronization. In order to fill the arising logical gaps, we suggest, among others, to weaken the second postulate of STR to a form directly confirmed by experiments and make new measurements of Maxwell's constant with accuracy comparable with that of the speed of light.
description: 17 pages, 1 figure
Replication data for: Factors determining parasite abundance in three freshwater fish, European perch (Perca fluviatilis), European whitefish (Coregonus lavaretus), and Arctic charr (Salvelinus alpinus), in an oligotrophic lake, southern Norway.
Creators: name: Olk, Tom Robin
name: Henriksen, Ann-Cecilie
name: Dolven, Solveig Irene
name: Haukø, Mathias Leithe
name: Lydersen, Espen
name: Mo, Tor Atle
Publisher: name: University of South-Eastern Norway
Year: 2023
Subjects: classificationCode: 300909
subject: Veterinary parasitology
classificationCode: 320704
subject: Medical parasitology
classificationCode: 310399
subject: Ecology not elsewhere classified

description: Figures, data and software code for Factors determining parasite abundance in three freshwater fish, European perch (Perca fluviatilis), European whitefish (Coregonus lavaretus), and Arctic charr (Salvelinus alpinus), in an oligotrophic lake, southern Norway.Article Abstract - Related PublicationTemporal and spatial variations in macroparasite status were investigated in European perch, Perca fluviatilis, European whitefish, Coregonus lavaretus, and Arctic charr, Salvelinus alpinus in Lake Norsjø (Southern Norway), based on gillnet fishing in three locations in the spring, summer, and fall 2018. In addition, length, weight, age, sex, δ13C, and δ15N were determined. Parasite abundance was modelled using negative binomial generalized linear models in relation to fish metrics, season, and sampling location. The most prevalent parasite species were determined by the diet and habitat of the host. European perch was mainly infected by acanthocephalans, European whitefish mainly infected by acanthocephalans and cestodes, and Arctic charr mainly infected by cestodes. The most prevalent parasites in European perch are transmitted by benthic animals. Parasites in European whitefish are transmitted by both benthic animals and copepods, while the most prevalent parasites in Arctic charr are copepod transmitted. This corresponds well with the δ13C signatures in the three species, indicating that European perch primarily fed in the littoral zone (δ13C: -24.9 ± 2.5 ‰), Arctic charr in the pelagic and profundal zone (δ13C: -29.4 ± 1.1 ‰), while European whitefish both fed in the littoral and pelagic zone (δ13C: -28.3 ± 2.3 ‰) of Lake Norsjø. Individual abundances of parasites depended on host age, length, sex, δ15N, and season. Positive correlations between parasite abundance and host age, length, or trophic level measured as δ15N were most common, and occurred in all three host species. Many parasites accumulate with age, and larger hosts provide more diverse habitats for parasites.
Factors determining parasite abundance in three freshwater fish, European perch (Perca fluviatilis), European whitefish (Coregonus lavaretus), and Arctic charr (Salvelinus alpinus), in an oligotrophic lake, southern Norway.
Creators: name: Olk, Tom Robin
name: Henriksen, Ann-Cecilie
name: Dolven, Solveig Irene
name: Haukø, Mathias Leithe
name: Lydersen, Espen
name: Mo, Tor Atle
Publisher: name: University of South-Eastern Norway
Year: 2020
Subjects: classificationCode: 300909
subject: Veterinary parasitology
classificationCode: 320704
subject: Medical parasitology
classificationCode: 310399
subject: Ecology not elsewhere classified

description: Figures, data and software code for Factors determining parasite abundance in three freshwater fish, European perch (Perca fluviatilis), European whitefish (Coregonus lavaretus), and Arctic charr (Salvelinus alpinus), in an oligotrophic lake, southern Norway.
Magnonic Interferometric Switch for Multi-Valued Logic Circuits
Creators: name: Balynsky, M.
name: Kozhevnikov, A.
name: Khivintsev, Y.
name: Bhowmick, T.
name: Gutierrez, D.
name: Chiang, H.
name: Dudko, G.
name: Filimonov, Y.
name: Liu, G.
name: Jiang, C.
name: Balandin, A. A.
name: Lake, R.
name: Khitun, A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigated a possible use of the magnonic interferometric switches in multi-valued logic circuits. The switch is a three-terminal device consisting of two spin channels where input, control, and output signals are spin waves. Signal modulation is achieved via the interference between the source and gate spin waves. We report experimental data on a micrometer scale prototype based on Y3Fe2(FeO4)3 structure. The output characteristics are measured at different angles of the bias magnetic field. The On/Off ratio of the prototype exceeds 36 dB at room temperature. Experimental data is complemented by the theoretical analysis and the results of micro magnetic simulations showing spin wave propagation in a micrometer size magnetic junction. We also present the results of numerical modeling illustrating the operation of a nanometer-size switch consisting of just 20 spins in the source-drain channel. The utilization of spin wave interference as a switching mechanism makes it possible to build nanometer-scale logic gates, and minimize energy per operation, which is limited only by the noise margin. The utilization of phase in addition to amplitude for information encoding offers an innovative route towards multi-state logic circuits. We describe possible implementation of the three-value logic circuits based on the magnonic interferometric switches. The advantages and shortcomings inherent in interferometric switches are also discussed.