cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Statistics of a 2D immersed granular gas magnetically forced in volume
Creators: name: Gorce, Jean-Baptiste
name: Falcon, Eric
Publisher: name: arXiv
Year: 2023
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We present an experimental study of the dynamics of a set of magnets within a fluid in which a remote torque applied by a vertical oscillating magnetic field transfers angular momentum to individual magnets. This system differs from previous experimental studies of granular gas where the energy is injected by vibrating the boundaries. Here, we do not observe any cluster formation, orientational correlation and equipartition of the energy. The magnets' linear velocity distributions are stretched exponentials, similar to 3D boundary-forced dry granular gas systems, but the exponent does not depend on the number of magnets. The value of the exponent of the stretched exponential distributions is close to the value of 3/2 previously derived theoretically. Our results also show that the conversion rate of angular momentum into linear momentum during the collisions controls the dynamics of this homogenously-forced granular gas. We report the differences between this homogeneously-forced granular gas, ideal gas, and nonequilibrium boundary-forced dissipative granular gas.
Non-Detection of HC$_{11}$N toward TMC-1: Constraining the Chemistry of Large Carbon-Chain Molecules
Creators: name: Loomis, Ryan A.
name: Shingledecker, Christopher N.
name: Langston, Glen
name: McGuire, Brett A.
name: Dollhopf, Niklaus M.
name: Burkhardt, Andrew M.
name: Corby, Joanna
name: Booth, Shawn T.
name: Carroll, P. Brandon
name: Turner, Barry
name: Remijan, Anthony J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Bell et al. (1997) reported the first detection of the cyanopolyyne HC$_{11}$N toward the cold dark cloud TMC-1; no subsequent detections have been reported toward any source. Additional observations of cyanopolyynes and other carbon-chain molecules toward TMC-1 have shown a log-linear trend between molecule size and column density, and in an effort to further explore the underlying chemical processes driving this trend, we have analyzed GBT observations of HC$_9$N and HC$_{11}$N toward TMC-1. Although we find an HC$_9$N column density consistent with previous values, HC$_{11}$N is not detected and we derive an upper limit column density significantly below that reported in Bell et al. Using a state-of-the-art chemical model, we have investigated possible explanations of non-linearity in the column density trend. Despite updating the chemical model to better account for ion-dipole interactions, we are not able to explain the non-detection of HC$_{11}$N, and we interpret this as evidence of previously unknown carbon-chain chemistry. We propose that cyclization reactions may be responsible for the depleted HC$_{11}$N abundance, and that products of these cyclization reactions should be investigated as candidate interstellar molecules.
description: 10 pages, 7 figures, 3 tables, accepted for publication in MNRAS
Inelastic nuclear scattering from neutrinos and dark matter
Creators: name: Dutta, Bhaskar
name: Huang, Wei-Chih
name: Newstead, Jayden L.
name: Pandey, Vishvas
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Neutrinos with energy of order 10~MeV, such as from pion decay-at-rest sources, are an invaluable tool for studying low-energy neutrino interactions with nuclei -- previously enabling the first measurement of coherent elastic neutrino-nucleus scattering. Beyond elastic scattering, neutrinos and dark matter in this energy range also excite nuclei to its low-lying nuclear states, providing an additional physics channel. Here, we consider neutral-current inelastic neutrino-nucleus and dark matter(DM)-nucleus scattering off $^{40}$Ar, $^{133}$Cs, and $^{127}$I nuclei that are relevant to a number of low-threshold neutrino experiments at pion decay-at-rest facilities. We carry out large scale nuclear shell model calculations of the inelastic cross sections considering the full set of electroweak multipole operators. Our results demonstrate that Gamow-Teller transitions provide the dominant contribution to the cross section and that the long-wavelength limit provides a reasonable approximation to the total cross section for neutrino sources. We show that future experiments will be sensitive to this channel and thus these results provide additional neutrino and DM scattering channels to explore at pion decay-at-rest facilities.
description: 16 pages, 12 figures, published version
Properties of Healthcare Teaming Networks as a Function of Network Construction Algorithms
Creators: name: Zand, Martin S.
name: Trayhan, Melissa
name: Farooq, Samir A.
name: Fucile, Christopher
name: Ghoshal, Grourab
name: White, Robert J.
name: Quill, Caroline M.
name: Rosenberg, Alexander
name: Serrano, Hugo
name: Chafi, Hassan
name: Boudreau, Timothy
Publisher: name: arXiv
Year: 2016
Subjects: subject: Social and Information Networks (cs.SI)
subject: Data Structures and Algorithms (cs.DS)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Network models of healthcare systems can be used to examine how providers collaborate, communicate, refer patients to each other. Most healthcare service network models have been constructed from patient claims data, using billing claims to link patients with providers. The data sets can be quite large, making standard methods for network construction computationally challenging and thus requiring the use of alternate construction algorithms. While these alternate methods have seen increasing use in generating healthcare networks, there is little to no literature comparing the differences in the structural properties of the generated networks. To address this issue, we compared the properties of healthcare networks constructed using different algorithms and the 2013 Medicare Part B outpatient claims data. Three different algorithms were compared: binning, sliding frame, and trace-route. Unipartite networks linking either providers or healthcare organizations by shared patients were built using each method. We found that each algorithm produced networks with substantially different topological properties. Provider networks adhered to a power law, and organization networks to a power law with exponential cutoff. Censoring networks to exclude edges with less than 11 shared patients, a common de-identification practice for healthcare network data, markedly reduced edge numbers and greatly altered measures of vertex prominence such as the betweenness centrality. We identified patterns in the distance patients travel between network providers, and most strikingly between providers in the Northeast United States and Florida. We conclude that the choice of network construction algorithm is critical for healthcare network analysis, and discuss the implications for selecting the algorithm best suited to the type of analysis to be performed.
description: With links to comprehensive, high resolution figures and networks via figshare.com
A Pacemaker with P=2.48 hour Modulated the Generator of Flares in the X-ray Light Curve of Sgr A* in the year 2012
Creators: name: Leibowitz, Elia M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: In an intensive observational campaign in the 9 month duration of Chandra X-ray Visionary Project that was conducted in the year 2012, 39 large X-ray flares of Sgr A* were recorded. An analysis of the times of the observed flares reveals that the 39 flares are separated in time by intervals that are grouped around integer numbers times 0.10333 days. This time interval is thus the period of a uniform grid of equally spaced points on the time axis. The grouping of the flares around tic marks of this grid is derived from the data with at least a 3.2 σ level of statistical significance. No signal of any period can be found among 22 flares recorded by Chandra in the years 2013-2014. If the 0.10333 d period is that of a nearly circular Keplerian orbit around the blackhole at the center of the Galaxy, its radius is at 7.6 Schwarzschild radii. Large flares were more likely to be triggered when the agent responsible for their outbursts was near the peri-center phase of its slightly eccentric orbit.
description: Accepted for publication in New Astronomy
Engineering Double-Well Potentials with Variable-Width Annular Josephson Tunnel Junctions
Creators: name: Monaco, Roberto
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Long Josephson tunnel junction are non-linear transmission lines that allow propagation of current vortices (fluxons) and electromagnetic waves and are used in various applications within superconductive electronics. Recently, the Josephson vortex has been proposed as a new superconducting qubit. We describe a simple method to create a double-well potential for an individual fluxon trapped in a long elliptic annular Josephson tunnel junction characterized by an intrinsic non-uniform width. The distance between the potential wells and the height of the inter-well potential barrier are controlled by the strength of an in-plane magnetic field. The manipulation of the vortex states can be achieved by applying a proper current ramp across the junction. The read-out of the state is accomplished by measuring the vortex depinning current in a small magnetic field. An accurate one-dimensional sine-Gordon model for this strongly non-linear system is presented, from which we calculate the position-dependent fluxon rest-mass, its Hamiltonian density and the corresponding trajectories in the phase space. We examine the dependence of the potential properties on the annulus eccentricity and its electrical parameters and address the requirements for observing quantum-mechanical effects, as discrete energy levels and tunneling, in this two-state system.
description: 18 pages, 9 figures
Aluminum functionalized silicene: a potential anode material for alkali metal ion batteries
Creators: name: Ipaves, Bruno
name: Justo, João F.
name: Assali, Lucy V. C.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We have investigated the possibility of using aluminum functionalized silicene trilayers (ABC-Si$_4$Al$_2$) as an anode material for alkali metal ion batteries (AMIBs). First, we studied the thermodynamic stability of ABC-Si$_4$Al$_2$ using ab-initio molecular dynamics simulations, showing that this material remains stable up to 600 K. Then, we explored the properties of alkali metal atoms (Li, Na, K) adsorption in ABC-Si$_4$Al$_2$, finding several available sites with high adsorption energies. Moreover, we computed the diffusion properties of those atoms along high-symmetry paths using the nudged elastic band method. The results indicated diffusion barriers as low as those in graphite, especially for Na (0.32 eV) and K (0.22 eV), which allows those ions to migrate easily on the material's surface. Our studies also revealed that the full loaded Li$_4$Si$_4$Al$_2$, Na$_2$Si$_4$Al$_2$, and K$_2$Si$_4$Al$_2$ systems provide low open-circuit voltage, ranging from 0.14 to 0.49 V, and large theoretical capacity of 645 mAh/g for Li- and 322 mAh/g for Na- and K-ion batteries, values that are close to the ones in other anode materials, such as graphite, TiO$_2$, and silicene-based systems. Those results indicate that aluminum functionalized few-layer silicene is a promising material for AMIBs anodes, particularly for Na- and K-ion batteries.
Baryons and Chiral Symmetry
Creators: name: Liu, Keh-Fei
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The relevance of chiral symmetry in baryons is highlighted in three examples in the nucleon spectroscopy and structure. The first one is the importance of chiral dynamics in understanding the Roper resonance. The second one is the role of chiral symmetry in the lattice calculation of $πN σ$ term and strangeness. The third one is the role of chiral $U(1)$ anomaly in the anomalous Ward identity in evaluating the quark spin and the quark orbital angular momentum. Finally, the chiral effective theory for baryons is discussed.
description: To appear in G.E. Brown Memorial Volume
Societal Impact, the SDGs, and the Humanities: A case study from the University of Iceland
Creators: name: Sigurðarson, Eiríkur Smári
Publisher: name: Zenodo
Year: 2022

description: The research can be relevant for how evaluations of societal impact based on the SDGs are developed in a direction that is more inclusive of the humanities and more relevant for the development of universities with the goal of benefiting society.
Deep Reinforcement Learning for Turbulence Modeling in Large Eddy Simulations
Creators: name: Kurz, Marius
name: Offenhäuser, Philipp
name: Beck, Andrea
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Artificial Intelligence (cs.AI)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Machine Learning (cs.LG)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Over the last years, supervised learning (SL) has established itself as the state-of-the-art for data-driven turbulence modeling. In the SL paradigm, models are trained based on a dataset, which is typically computed a priori from a high-fidelity solution by applying the respective filter function, which separates the resolved and the unresolved flow scales. For implicitly filtered large eddy simulation (LES), this approach is infeasible, since here, the employed discretization itself acts as an implicit filter function. As a consequence, the exact filter form is generally not known and thus, the corresponding closure terms cannot be computed even if the full solution is available. The reinforcement learning (RL) paradigm can be used to avoid this inconsistency by training not on a previously obtained training dataset, but instead by interacting directly with the dynamical LES environment itself. This allows to incorporate the potentially complex implicit LES filter into the training process by design. In this work, we apply a reinforcement learning framework to find an optimal eddy-viscosity for implicitly filtered large eddy simulations of forced homogeneous isotropic turbulence. For this, we formulate the task of turbulence modeling as an RL task with a policy network based on convolutional neural networks that adapts the eddy-viscosity in LES dynamically in space and time based on the local flow state only. We demonstrate that the trained models can provide long-term stable simulations and that they outperform established analytical models in terms of accuracy. In addition, the models generalize well to other resolutions and discretizations. We thus demonstrate that RL can provide a framework for consistent, accurate and stable turbulence modeling especially for implicitly filtered LES.
description: 17 pages, 9 figures. Accepted Manuscript
Schroedinger electrons interacting with optical gratings: quantum mechanical study of the inverse Smith Purcell effect
Creators: name: Talebi, Nahid
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences
subject: 65Pxx

description: Slow swift electrons with low self-inertia interact differently with matter and light in comparison with their relativistic counterparts: they are easily recoiled, reflected, and also diffracted form optical gratings and nanostructures. As a consequence, they can be also better manipulated into the desired shape. For example, they get bunched quite fast in interaction with acceleration gratings in presence of an external electromagnetic radiation, a phenomenon which can be desirable in development of superradiant coherent light sources. Here, I examine the spatiotemporal behavior of pulsed electron wave packets at low energies interacting with pulsed light and optical gratings, using a quantum-mechanical self-consistent numerical toolbox which is introduced here. It will be shown that electron pulses are accelerated very fast in interaction with the near-field of the grating, demanding that a synchronicity condition is met. To prevent the electrons to be transversely deflected from the grating a symmetric double-grating configuration is necessary. It is found that even in this configuration, diffraction due to the interaction of the electron with the standing-wave light inside the gap between the gratings, is a source of defocusing. Moreover, the longitudinal broadening of the electron pulse directly affects the final shape of the electron wave packet due to the occurrence of multiple electron-photon scatterings. These investigations pave the way towards the design of more efficient electron-driven photon sources and accelerators.
description: 8 Figures, 20 pages
Photometric variability of blue straggler stars in M67 with TESS and K2
Creators: name: Vernekar, Nagaraj
name: Subramaniam, Annapurni
name: Jadhav, Vikrant V.
name: Bowman, Dominic M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Blue straggler stars (BSSs) are formed through mass transfer or mergers in binaries. The recent detections of white dwarf (WD) companions to BSSs in M67 suggested a mass transfer pathway of formation. In search of a close companion to five BSSs in M67 that are known to be spectroscopic binaries, we study the light curves from K2 and TESS data. We use PHOEBE to analyse the light curves and estimate the properties of the companions. We detect variability in WOCS 1007, and the light curve is dominated by ellipsoidal variation. Using the light curve and radial velocity measurements, we estimate its orbital period to be 4.212$\pm$0.041 d and $e$ = 0.206$\pm$002. The mass of the companion is estimated to be 0.22$\pm$0.05 M$_{\odot}$ with a radius of 0.078$\pm$0.027 R$_{\odot}$, confirming it to be a low mass WD with T$_{\rm eff}$ = 14300$\pm$1100 K. The estimated mass of the BSS, 1.95$\pm$0.26 M$_{\odot}$, is similar to that estimated from isochrones. The BSS in WOCS 1007 shows $δ$ Scuti pulsations, although it is slightly deformed and likely to be formed through an efficient mass transfer. Though we detect a light curve for WOCS 4003 showing grazing eclipse with ellipsoidal variation, the estimated parameters are inconclusive. Apart from the 0.44 d period, we found smaller eclipses with a period of 1.1 d, suggesting a compact triple system. In the case of WOCS 4003, WOCS 5005, and WOCS 1025, no eclipses or pulsations are detected, confirming the absence of any short-period inner binary with high inclination in these BSSs.
description: 15 pages, 10 figures. Accepted for publication in MNRAS
Héberger des revues électroniques : Pourquoi ? Comment ?
Creators: name: Claivaz, Jean-Blaise
Publisher: name: Zenodo
Year: 2023

description: Cette session mettra à l’honneur le logiciel OJS (Open Journal Systems) et brossera un portrait introductif de ses forces et ses faiblesses, de ce qu’il fait et surtout, de ce qu’il ne fait pas. Cet atelier propose aux participant·e·s de co-créer un journal fictif pour s’essayer à l’utilisation de la plateforme et au réglage de ses différents paramètres : apparence, abonnement, type de relecture par les pairs, formats, etc.
 Les participant·e·s seront dans un deuxième temps invité-es à créer une équipe éditoriale éphémère afin d’explorer les arcanes et le fonctionnement au jour le jour d’un journal et de prendre le rôle de ses différents acteurs et actrices (réception des articles, demandes de corrections, édition et publication).
There Ain't No Such Thing as a Free Custom Memory Allocator
Creators: name: Kudrjavets, Gunnar
name: Thomas, Jeff
name: Kumar, Aditya
name: Nagappan, Nachiappan
name: Rastogi, Ayushi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: Using custom memory allocators is an efficient performance optimization technique. However, dependency on a custom allocator can introduce several maintenance-related issues. We present lessons learned from the industry and provide critical guidance for using custom memory allocators and enumerate various challenges associated with integrating them. These recommendations are based on years of experience incorporating custom allocators into different industrial software projects.
description: 4 pages. To be published in 38th IEEE International Conference on Software Maintenance and Evolution (ICSME 2022), Oct 3-7, 2022, Limassol, Cyprus
Condensation in Dust-Enriched Systems
Creators: name: Ebel, Denton S.
name: Grossman, Lawrence
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Chemical Physics (physics.chem-ph)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: Full chemical equilibrium calculations of the sequence of condensation of the elements from cosmic gases made by total vaporization of dust-enriched systems were performed to investigate the oxidation state of the resulting condensates. Computations included 23 elements and 374 gas species over a range of -3=log10(total P) to -6 bar and for enrichments to 1000x in dust of C1 chondritic composition relative to a system of solar composition. Because liquids are stable condensates in these systems, the MELTS non-ideal solution model for silicate liquids was used. Condensation at logP=-3 bar and dust enrichments of 100x, 500x and 1000x occurs at oxygen fugacities of IW-3.1, IW-1.7 and IW-1.2, respectively, and, at the temperature of cessation of direct condensation of olivine from the vapor, yields X(fayalite) of 0.019, 0.088 and 0.164, respectively. Silicate liquid is a stable condensate at dust enrichments >~12.5x at logP=-3. At 1000x, the Na and K oxide contents of the last liquid reach 10.1 and 1.3 wt%, respectively, at logP=-3 bar. At logP=-3 bar, iron sulfide liquids are stable condensates at dust enrichments at least as low as 500x, and the predicted distribution of Fe between metal, silicate and sulfide at 1310K and a dust enrichment of 560x matches that found in H chondrites, and at 1330K and 675x matches that of L chondrites prior to metal loss. With some exceptions, many chondrule glass compositions fall along bulk composition trajectories for liquids in equilibrium with cosmic gases at logP=-3 bar and dust enrichments between 600x and 1000x. If these chondrules formed by secondary melting of mixtures of condensates that formed at different T, nebular regions with characteristics such as these would have been necessary to prevent loss of Na by evaporation and FeO by reduction from the liquid precursors, assuming that liquids and gas were hot for enough time to have equilibrated.
description: 58 pages, 19 figures, 8 tables
Open Data – Sharing practices and the role of research contexts
Creators: name: Velden, Theresa
name: Ambrasat, Jens
Publisher: name: Zenodo
Year: 2022

description: In this short empirical paper, we have argued that more attention needs to be paid to research contexts when considering Open Data practices. We have shown evidence that the coarse disciplinary classifications frequently used, conceal substantial differences in data practices and sharing at a sub-field level. Further, we have shown that these variances have to do with the specific types of data and the specific role of the data in the research process. Here a central characteristic is the relationship of data production and data use. Researchers who are self-sufficient in that they produce the data needed for their own research and do not use data from third parties tend to share their (own) data rather less frequently compared to those who also use data from third parties. Because this association in turn might be entangled with further aspects relating to the type data, it would be worth taking a further look in this relation, which we cannot do here. Despite its increased depth of focus on field differences compared to previous multidisciplinary surveys, this quantitative study is only a first approximation to the concrete research contexts. To advance our understanding of the influence of research conditions on sharing rates, we need to combine quantitative analysis with qualitative studies, and continue to refine survey instruments in order to capture relevant epistemic differences that do not align with formal disciplinary classifications. Our results underline the point made by Gläser, that an important methodological precondition for survey research in order to be relevant for science studies is to move beyond the rigidity of formal discipline-level field classifications and develop instruments that are better suited to capture differences in research conditions. We conclude that in order to develop a deeper understanding of the variations in rates of sharing, future research on Open Data needs to attend to the specific research contexts, their data economies and their underlying systems of epistemic practices.
The fourth dimension of the nucleon structure: spacetime analysis of the timelike electromagnetic proton form factors
Creators: name: Bianconi, Andrea
name: Tomasi-Gustafsson, Egle
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: As well known, spacelike proton form factors expressed in the Breit frame may be interpreted as the Fourier transform of static space distributions of electric charge and current. In particular, the electric form factor is simply the Fourier transform of the charge distribution $F(q)=\int e^{i\vec q \cdot \vec r} ρ(r)d^3r$. We don't have an intuitive interpretation of the same level of simplicity for the proton timelike form factor appearing in the reactions $e^+e^-\leftrightarrow \bar{p}p$. However, one may suggest that in the center of mass (CM) frame, where $q_μx^μ=qt$, a timelike electric form factor is the Fourier transform $F(q) =\int e^{iqt} R(t)dt$ of a function $R(t)$ expressing how the electric properties of the forming (or annihilating) proton-antiproton pair evolve in time. Here we analyze in depth this idea, show that the functions $ρ(r)$ and $R(t)$ can be formally written as the time and space integrals of a unique correlation function depending on both time and space coordinates.
description: 8 figures, 15 pages
One-dimensional topological superconductivity based entirely on phase control
Creators: name: Lesser, Omri
name: Oreg, Yuval
name: Stern, Ady
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Topological superconductivity in one dimension requires time-reversal symmetry breaking, but at the same time it is hindered by external magnetic fields. We offer a general prescription for inducing topological superconductivity in planar superconductor-normal-superconductor-normal-superconductor (SNSNS) Josephson junctions without applying any magnetic fields on the junctions. Our platform relies on two key ingredients: the three parallel superconductors form two SNS junctions with phase winding, and the Fermi velocities for the two spin branches transverse to the junction must be different from one another. The two phase differences between the three superconductors define a parameter plane which includes large topological regions. We analytically derive the critical curves where the topological phase transitions occur, and corroborate the result with a numerical calculation based on a tight-binding model. We further propose material platforms with unequal Fermi velocities, establishing the experimental feasibility of our approach.
description: 5+10 pages, 3+8 figures
Mysterious Occurrences: Representation, Resiliency, and Redundancy in Native Plant Populations
Creators: name: Ewing, Rhea
name: Hackett, Rachel
name: Monfils, Anna
Publisher: name: QUBES Educational Resources
Year: 2024

description: Meet Rachel Hackett, a conservation plant biologist at the Michigan Natural Features Inventory.  We learn about Rachel's job and the restoration of threatened and endangered species. Rachel provides some examples of "new" populations and students discuss ways to determine if the population is a remnant or introduced population.
Experimental Investigation of Condensation Predictions for Dust-Enriched Systems
Creators: name: Ustunisik, Gokce
name: Ebel, Denton S.
name: Walker, David
name: Boesenberg, Joseph S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: Condensation models describe the equilibrium distribution of elements between coexisting mineral solid solutions, silicate liquid, and vapor in a closed chemical system, vapor phase always present, using equations of state of the phases involved at a fixed total P (< 1 bar) and temperature T. The VAPORS code uses a CaO-MgO-Al$_2$O$_3$-SiO$_2$ liquid model at T above the stability field of olivine and the MELTS algorithm at lower T. Quenched high-T crystal + liquid assemblages are preserved in meteorites as Type B Ca-, Al-rich inclusions (CAIs) and olivine-rich ferromagnesian chondrules. Experimental tests of compositional regions may clarify the nature of the phases present, the phase boundaries, and the partition of trace elements among these phases. Twenty-three Pt-loop equilibrium experiments in seven phase fields on twelve bulk compositions at specific T and dust enrichment factors tested the predicted stability fields of forsteritic olivine (Mg$_2$SiO$_4$), enstatite (MgSiO$_3$), Cr-bearing spinel (MgAl$_2$O$_4$), perovskite (CaTiO$_3$), melilite (Ca$_2$Al$_2$SiO$_7$ - Ca$_2$Mg$_2$Si$_2$O$_7$) and/or grossite (CaAl4O7) crystallizing from liquid. Experimental results for forsterite, enstatite, and grossite are in very good agreement with predictions, both in chemistry and phase abundances. On the other hand, the stability of spinel with olivine, and stability of perovskite and gehlenite are quite different from predictions. Perovskite is absent in all experiments. Even at low oxygen fugacity (IW-3.4), the most TiO$_2$-rich experiments do not crystallize Al-, Ti-bearing calcic pyroxene. The stability of spinel and olivine together is limited to a smaller phase field than is predicted. The melilite stability field is much larger than predicted, indicating a deficiency of current liquid or melilite activity models. In that respect, these experiments contribute to improving the data for calibrating thermodynamic models including MELTS.
description: 17 pages, 5 figures, 5 tables
title: Abnormal Electrical Potentials in Lower Limb Muscles After Ankle Sprain Grades I, II and III
Creators: name: Al-Shatti, Talal A.
Publisher: name: Old Dominion University Libraries
Year: 1999

description: Fibrillation and positive sharp wave potentials have been found after ankle sprain in muscles around the injured joint. The purpose of this study was to better define and explain the reaction of the muscles around the ankle joint after grades I, II and m ankle sprains. Methods: Fifteen subjects (9 males and 6 females, mean age of 33.2 years) with ankle sprains voluntarily participated in this study. A stress x-ray was done to determine the grade of ankle sprain. Nerve conduction velocity and EMO studies were done three weeks after the injury. None of the patients in this study manifested any signs of sensory loss. Results: the subjects had normal latencys and conduction velocities for motor and sensory nerves of the involved ankle. Forty-seven percent of the subjects had fibrillation potentials in the abductor hallucis muscle and 40% had these potentials in the abductor digiti minimi muscle. Thirty-three percent of patients had sensitive sharp wave potentials in the abductor hallucis muscle, whereas 27% had the positive sharp waves in the abductor digiti minimi muscle. The results showed abnormal potentials in muscles supplied by both the peroneal and tibial nerves. There were no statistical differences among the three grades of ankle sprain groups. Conclusions: A greater than predicted percentage of subjects had fibrillation potentials and/or positive sharp waves in the small muscles of the foot following ankle sprain. Abnormalities in muscles innervated by two separate nerves indicates a cause other than direct nerve traction.
A slow-burning crisis: executive relations and the normalisation of distrust in Northern Ireland’s ‘cash for ash’ fiasco
Creators: name: Rice, Charis
name: CONNAUGHTON, BERNADETTE
name: Ratcliffe, Jenny
name: Somerville, Ian
Publisher: name: University of Limerick
Year: 2023
Subjects: classificationCode: 4408
subject: Political science
subject: FOS: Political science

description: This paper explores relationships between ministers, special advisers and civil servants through the lens of a high-profile government crisis in Northern Ireland (NI). Although political–administrative relationships are a mainstay of public administration research, we still have limited understanding of how these relationships feature and function within the ‘Westminster family’ of governance when operating within devolved institutions or post-conflict societies, nor of their role in crisis. We use Scott’s institutional pillars as an analytical framework and conduct a documentary analysis of public inquiry witness statements to explore the Renewable Heat Incentive crisis which led to the collapse of the NI legislature. Utilising a novel application of existing theory, we demonstrate that the implementation of the devolved, consociational power-sharing model incubated new governance norms, that prioritised and legitimised the agendas and actions of political actors (ministers and special advisers), over civil servants. Specifically, in understanding how relational norms – particularly distrust – feed public policy failure and institutional crisis, our findings contribute to this research area and to the broader public administration field. Government institutional crisis negatively impacts upon public service delivery and the wider health of democracy. Understanding such crises is an important first step in their amelioration.
Atomic Ordering in Cubic Bismuth Telluride Alloy Phases at High Pressure
Creators: name: Loa, I.
name: Bos, J. -W. G.
name: Downie, R. A.
name: Syassen, K.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Pressure-induced transitions from ordered intermetallic phases to substitutional alloys to semi-ordered phases were studied in a series of bismuth tellurides. Using angle-dispersive x-ray diffraction, the compounds Bi4Te5, BiTe, and Bi2Te were observed to form alloys with the disordered body-centered cubic (bcc) crystal structure upon compression to above 14--19 GPa at room temperature. The BiTe and Bi2Te alloys and the previously discovered high-pressure alloys of Bi2Te3 and Bi4Te3 were all found to show atomic ordering after gentle annealing at very moderate temperatures of ~100°C. Upon annealing, BiTe transforms from the bcc to the B2 (CsCl) crystal structure type, and the other phases adopt semi-disordered variants thereof, featuring substitutional disorder on one of the two crystallographic sites. The transition pressures and atomic volumes of the alloy phases show systematic variations across the Bi_mTe_n series including the end members Bi and Te. First-principles calculations were performed to characterize the electronic structure and chemical bonding properties of B2-type BiTe and to identify the driving forces of the ordering transition. The calculated Fermi surface of B2-type BiTe has an intricate structure and is predicted to undergo three topological changes between 20 and 60 GPa.
description: 8 pages, 11 figures, accepted for publication in Phys. Rev. B
Thermochemical Stability of Low-Iron, Manganese-Enriched Olivine in Astrophysical Environments
Creators: name: Ebel, Denton S.
name: Weisberg, Michael K.
name: Beckett, John R.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: Low-iron, manganese-enriched (LIME) olivine grains are found in cometary samples returned by the Stardust mission to comet 81P/Wild 2. Similar grains are found in primitive meteoritic clasts and unequilibrated meteorite matrix. LIME olivine is thermodynamically stable in a vapor of solar composition at high temperature at total pressures of a millibar to a microbar, but enrichment of solar composition vapor in a dust of chondritic composition causes the FeO/MnO ratio of olivine to increase. The compositions of LIME olivines in primitive materials indicate oxygen fugacities close to that of a very reducing vapor of solar composition. The compositional zoning of LIME olivines in amoeboid olivine aggregates is consistent with equilibration with nebular vapor in the stability field of olivine, without reequilibration at lower temperatures. A similar history is likely for LIME olivines found in comet samples and in interplanetary dust particles. LIME olivine is not likely to persist in nebular conditions in which silicate liquids are stable.
description: 15 pages, 5 figures
Neutron-gamma competition for $β$-delayed neutron emission
Creators: name: Mumpower, Matthew
name: Kawano, Toshihiko
name: Moller, Peter
Publisher: name: arXiv
Year: 2016
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We present a coupled Quasi-particle Random Phase Approximation and Hauser-Feshbach (QRPA+HF) model for calculating delayed particle emission. This approach uses microscopic nuclear structure information which starts with Gamow-Teller strength distributions in the daughter nucleus, and then follows the statistical decay until the initial available excitation energy is exhausted. Explicitly included at each particle emission stage is $γ$-ray competition. We explore this model in the context of neutron emission of neutron-rich nuclei and find that neutron-gamma competition can lead to both increases and decreases in neutron emission probabilities, depending on the system considered. A second consequence of this formalism is a prediction of more neutrons on average being emitted after $β$-decay for nuclei near the neutron dripline compared to models that do not consider the statistical decay.
description: 9 pages, 6 figures, submitted
Modelagem BIM para desenvolvimento de gêmeo digital visando a segurança e manutenção de barragens em operação
Creators: name: Cortes Pires, João Rodolfo
name: BARBOSA, Paulo Sergio Franco
name: Cuperschmid, Ana Regina
name: LAZOR, Rodrigo da Silva
name: RESENDE, Pedro Nogueira de
name: PEREIRA, Rafael Chehab Canto
Publisher: name: figshare
Year: 2023
Subjects: classificationCode: 400504
subject: Construction engineering
classificationCode: 400501
subject: Architectural engineering

description: O monitoramento e controle de barragens demandam estratégias e abordagens eficientes para o gerenciamento de ativos e dados. Os gêmeos digitais surgem como solução, permitindo a representação digital de componentes físicos e o armazenamento de informações durante a operação e manutenção das barragens. Neste artigo, é descrito o processo de modelagem BIM da Hidrelétrica Foz do Chapecó, com destaque para a importância da nomenclatura na troca de dados entre sensores e modelos por meio do gêmeo digital. Padrões abertos como IFC e COBie foram adotados para garantir interoperabilidade. A nomenclatura proposta permitiu padronizar os parâmetros necessários que serão utilizados para transmitir dados dos sensores ao gêmeo digital.
Demonstration of sub-luminal propagation of single-cycle terahertz pulses for particle acceleration
Creators: name: Walsh, D. A.
name: Lake, D. S.
name: Snedden, E. W.
name: Cliffe, M. J.
name: Graham, D. M.
name: Jamison, S. P.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The sub-luminal phase velocity of electromagnetic waves in free space is generally unobtainable, being closely linked to forbidden faster than light group velocities. The requirement of effective sub-luminal phase-velocity in laser-driven particle acceleration schemes imposes a fundamental limit on the total acceleration achievable in free-space, and necessitates the use of dielectric structures and waveguides for extending the field-particle interaction. Here we demonstrate a new travelling-source and free space propagation approach to overcoming the sub-luminal propagation limits. The approach exploits the relative ease of generating ultrafast optical sources with slow group velocity propagation, and a group-to-phase front conversion through non-linear optical interaction near a material-vacuum boundary. The concept is demonstrated with two terahertz generation processes, non-linear optical rectification and current-surge rectification. The phase velocity is tunable, both above and below vacuum speed of light $c$, and we report measurements of longitudinally polarized electric fields propagating between $0.77c$ and $1.75c$. The ability to scale to multi-MV/m field strengths is demonstrated. Our approach paves the way towards the realization of cheap and compact particle accelerators with unprecedented femtosecond scale control of particles.
Extensions of I-Reversible Rings
Creators: name: Lama, Vivek Bhabani
name: N, Suhas B
name: Mazumdar, Susobhan
name: DSouza, Raisa
Publisher: name: arXiv
Year: 2022
Subjects: subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 16U80, 16U40, 16U99

description: A ring $R$ is said to be i-reversible if for every $a,b$ $\in$ $R$, $ab$ is a non-zero idempotent implies $ba$ is an idempotent. It is known that the rings $M_n(R)$ and $T_n(R)$ (the ring of all upper triangular matrices over $R$) are not i-reversible for $n \geq 3$. In this article, we provide a non-trivial i-reversible subring of $M_n(R)$ when $n \geq 3$ and $R$ has only trivial idempotents. We further provide a maximal i-reversible subring of $T_n(R)$ for each $n\geq 3$, if $R$ is a field. We then give conditions for i-reversibility of Trivial, Dorroh and Nagata extensions. Finally, we give some independent sufficient conditions for i-reversibility of polynomial rings, and more generally, of skew polynomial rings.
description: Accepted for publication in the Journal of Algebra and its Applications
Raising the bar for bibliometric analysis
Creators: name: Boyack, Kevin W.
name: Klavans, Richard
name: Smith, Caleb
Publisher: name: Zenodo
Year: 2022

description: The introduction of new bibliometric software packages in recent years has led to an exponential increase in the publication rate of bibliometric analyses. A review of 46 recently published articles that used one of these software packages—VOSviewer—to visualize the structure and evolution of a set of documents, suggests that there are three areas where the quality of these studies can be easily improved. First, replication – only two of the 13 articles that used experts to screen out irrelevant papers provided specific information on the surviving sample. Second, robustness – only 10 of the 46 articles provided extensive, actionable discussion of structure. None of these provided sufficient explanation of structure-based findings. Third, relevance – journal-based analyses used bibliometrics to support preconceived positions—namely that the journal being analyzed was exceptional in some positive way, while keyword-based analyses were susceptible to author bias, contributing to the risk of misrepresentation of the area under study. We provide suggestions as to how the bibliometric community might improve the state of the art in a way that can be used by non-experts.
The Tayler instability at low magnetic Prandtl numbers: Chiral symmetry breaking and synchronizable helicity oscillations
Creators: name: Stefani, F.
name: Galindo, V.
name: Giesecke, A.
name: Weber, N.
name: Weier, T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The current-driven, kink-type Tayler instability (TI) is a key ingredient of the Tayler-Spruit dynamo model for the generation of stellar magnetic fields, but is also discussed as a mechanism that might hamper the up-scaling of liquid metal batteries. Under some circumstances, the TI involves a helical flow pattern which goes along with some alpha effect. Here we focus on the chiral symmetry breaking and the related impact on the alpha effect that would be needed to close the dynamo loop in the Tayler-Spruit model. For low magnetic Prandtl numbers, we observe intrinsic oscillations of the alpha effect. These oscillations serve then as the basis for a synchronized Tayler-Spruit dynamo model, which could possibly link the periodic tidal forces of planets with the oscillation periods of stellar dynamos.
description: 10 pages, 4 figures, extended proceedings paper of the PAMIR 2016 conference
Metal to Wigner-Mott insulator transition in two-leg ladders
Creators: name: Musser, Seth
name: Senthil, T.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study theoretically the quantum phase transition from a metal to a Wigner-Mott insulator at fractional commensurate filling on a two-leg ladder. We show that a continuous transition out of a symmetry-preserving Luttinger liquid metal is possible where the onset of insulating behavior is accompanied by the breaking of the lattice translation symmetry. At fillings $ν= 1/m$ per spin per unit cell, we find that the spin degrees of freedom also acquire a gap at the Wigner-Mott transition for odd integer $m$. In contrast for even integer $m$, the spin sector remains gapless and the resulting insulator is a ladder analog of the two-dimensional spinon surface state. In both cases, a charge neutral spinless mode remains gapless across the Wigner-Mott transition. We discuss physical properties of these transitions, and comment on insights obtained for thinking about continuous Wigner-Mott transitions in two-dimensional systems which are being studied in moire materials.
description: 19 pages, 3 figures, updated upon publication