cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Electronic effects on the radiation damage in high-entropy alloys
Creators: name: Orhan, Okan K.
name: Hendy, Mohamed
name: Ponga, Mauricio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: High-entropy alloys (HEAs) are exceptional candidates for radiation-resistant materials due to their complex local chemical environment and slow defect migration. Despite commonly overlooked, electronic effects on defects evolution in radiation environments also play a crucial role by dissipating excess energy through electron-phonon coupling and electronic heat conduction during cascade events. We present a systematic study on electronic properties in random-solid solutions (RSS) in four and five principal elements HEAs and their effect on defect formation, clustering, and recombination. Electronic properties, including electron-phonon coupling factor, the electronic specific heat, and the electronic thermal conductivity, are computed within first-principles calculations. Using the two-temperature molecular dynamics simulations, we show that the electron-phonon coupling factor and electronic specific heat play a critical role in Frenkel pairs formation. Specifically, the electron-phonon coupling factor quickly dissipates the kinetic energy during primary knock-on atom events via plasmon excitations and is subsequently dissipated via the free-electrons conduction. We show that these effects are more critical than the elastic distortion effects produced by the atomic mismatch. Of tremendous interest, we show that including lighter elements helps to increase the electron-phonon coupling factor, suggesting the possibility to improve radiation resistance in HEA through optimal composition.
Investigating complex networks with inverse models: analytical aspects of spatial leakage and connectivity estimation
Creators: name: Wens, Vincent
Publisher: name: arXiv
Year: 2014
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Neurons and Cognition (q-bio.NC)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Network theory and inverse modeling are two standard tools of applied physics, whose combination is needed when studying the dynamical organization of spatially distributed systems from indirect measurements. However, the associated connectivity estimation may be affected by spatial leakage, an artifact of inverse modeling that limits the interpretability of network analysis. This paper investigates general analytical aspects pertaining to this issue. First, the existence of spatial leakage is derived from the topological structure of inverse operators. Then, the geometry of spatial leakage is modeled and used to define a geometric correction scheme, which limits spatial leakage effects in connectivity estimation. Finally, this new approach for network analysis is compared analytically to existing methods based on linear regressions, which are shown to yield biased coupling estimates.
description: 19 pages, 4 figures, including 5 appendices; v2: minor edits, 1 appendix added; v3: expanded version, v4: minor edits
Thermodynamics and dynamics of coupled complex SYK models
Creators: name: Louw, Jan C.
name: van Manen, Linda M.
name: Jha, Rishabh
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: It has been known that the large-$q$ complex SYK model falls under the same universality class as that of van der Waals (mean-field) and saturates the Maldacena-Shenker-Stanford bound, both features shared by various black holes. This makes the SYK model a useful tool in probing the fundamental nature of quantum chaos and holographic duality. This work establishes the robustness of this shared universality class and chaotic properties for SYK-like models by extending to a system of coupled large-$q$ complex SYK models of different orders. We provide a detailed derivation of thermodynamic properties, specifically the critical exponents for an observed phase transition, as well as dynamical properties, in particular the Lyapunov exponent, via the out-of-time correlator calculations. Our analysis reveals that, despite the introduction of an additional scaling parameter through interaction strength ratios, the system undergoes a continuous phase transition at low temperatures, similar to that of the single SYK model. The critical exponents align with the Landau-Ginzburg (mean-field) universality class, shared with van der Waals gases and various AdS black holes. Furthermore, we demonstrate that the coupled SYK system remains maximally chaotic in the large-$q$ limit at low temperatures, adhering to the Maldacena-Shenker-Stanford bound, a feature consistent with the single SYK model. These findings establish robustness and open avenues for broader inquiries into the universality and chaos in complex quantum systems. We provide a detailed outlook for future work by considering the "very" low-temperature regime, where we discuss relations with the Hawking-Page phase transition observed in the holographic dual black holes. We present preliminary calculations and discuss the possible follow-ups that might be taken to make the connection robust.
description: 20 pages, 10 figures, 1 table, same as published version but in a different formatting style
title: Fall des jugendlichen Hochmuthes; [1771]
title: auf oeffentlicher Schaubühne vorgestellt von der lateinischen Grundschule zu Burghausen als diese auf höchste Freygebigkeit des ... Herrn Guarin ... Probsten in Baumburg, ... Abbten, ... mit sonderbaren Ehrenzeichen belohnet wurde den 22. und 26.ten Augusts im Jahr 1771
titleType: Subtitle
Creators: name: Braittenberger, Firmin
Publisher: name: Universitätsbibliothek der Ludwig-Maximilians-Universität München
Year: 2008

description: Perioche. - Mit dem Text des deutschen musik. Zwischenspiels. - In Fraktur
Heating of the intracluster medium by buoyant bubbles and sound waves
Creators: name: Iqbal, Asif
name: Majumdar, Subhabrata
name: Nath, Biman B.
name: Roychowdhury, Suparna
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Active galactic nuclei (AGN) powered by the central Super-Massive Black Holes (SMBHs) play a major role in modifying the thermal properties of the intracluster medium (ICM). In this work, we implement two AGN heating models: (i) by buoyant cavities rising through stratified ICM (effervescent model) and, (ii) by viscous and conductive dissipation of sound waves (acoustic model). Our aim is to determine whether these heating models are consistent with ICM observables and if one is preferred over the other. We assume an initial entropy profile of ICM that is expected from the purely gravitational infall of the gas in the potential of the dark matter halo. We then incorporate heating, radiative cooling, and thermal conduction to study the evolution of ICM over the age of the clusters. Our results are: (i) Both the heating processes can produce comparable thermal profiles of the ICM with some tuning of relevant parameters. (ii) Thermal conduction is crucially important, even at the level of 10\% of the Spitzer values, in transferring the injected energy beyond the central regions, and without which the temperature/entropy profiles are unrealistically high. (iii) The required injected AGN power scales with cluster mass as $M_{\rm vir}^{1.5}$ for both models. (iv) The required AGN luminosity is comparable with the observed radio jet power, reinforcing the idea that AGNs are the dominant heating source in clusters. (v) Finally, we estimate that the fraction of the total AGN luminosity available as the AGN mechanical luminosity at $0.02r_{500}$ is less than 0.05\%.
description: 13 pages, 5 figures, Accepted in MNRAS
An Introduction to Complex Game Theory
Creators: name: Dimou, Nick
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics
subject: 91A70, 91A05, 52B12, 11M26

description: The known results regarding two-player zero-sum games are naturally generalized in complex space and are presented through a complete compact theory. The payoff function is defined by the real part of the payoff function in the real case, and pure complex strategies are defined by the extreme points of the convex polytope $S_α^m:=\{z\in\mathbb{C}^m:$ $|argz|\leqqα,\;\sum_{i=1}^{m}z_i=1\}$ for "strategy argument" $α$ in $(0,\fracπ{2})e$. These strategies allow definitions and results regarding Nash equilibria, security levels of players and their relations to be extended in $\mathbb{C}^{m}$. A new constructive proof of the Minimax Theorem in complex space is given, which indicates a method for precisely calculating the equilibria of two-player zero-sum complex games. A simpler solution method of such games, based on the solutions of complex linear systems of the form $Bz=b$, is also obtained.
description: The abstract and introduction sections were changed to make the motivation more clear. Some omissions in Section 2, corrections in Sections 3, 5 and other minor changes were also made
Interplay between multiple scattering, emission, and absorption of light in the phosphor of a white light-emitting diode
Creators: name: Leung, V. Y. F.
name: Lagendijk, A.
name: Tukker, T. W.
name: Mosk, A. P.
name: IJzerman, W. L.
name: Vos, W. L.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We study light transport in phosphor plates of white light-emitting diodes (LEDs). We measure the broadband diffuse transmission through phosphor plates of varying YAG:Ce$^{3+}$ density. We distinguish the spectral ranges where absorption, scattering, and re-emission dominate. Using diffusion theory, we derive the transport and absorption mean free paths from first principles. We find that both transport and absorption mean free paths are on the order of the plate thickness. This means that phosphors in commercial LEDs operate well within an intriguing albedo range around 0.7. We discuss how salient parameters that can be derived from first principles control the optical properties of a white LED.
description: 14 pages, 9 figures
Interpretation of micromorphic constitutive relations for porous materials at the microscale via harmonic decomposition
Creators: name: Hütter, Geralf
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Micromorphic theories became an established tool to model size effects in materials like dispersion, localization phenomena or (apparently) size dependent properties. However, the formulation of adequate constitutive relations with its large number of constitutive relations and respective parameters hinders the usage of the full micromorphic theory, which has 18 constitutive parameters already in the isotropic linear elastic case. Although it is clear that these parameters are related to predicted size effects, the individual meaning of single parameters has been rather unclear. The present work tries to elucidate the interpretation of the constitutive relations and their parameters. For this purpose, a harmonic decomposition is applied to the governing equations of micromorphic theory. The harmonic modes are interpreted at the microscale using a homogenization method for a simple volume element with spherical pore. The resulting boundary-value problem at the microscale is solved analytically for the linear-elastic case using spherical harmonics resulting in closed-form expressions for all of the elastic 18 parameters. These values are used to predict the size effect in torsion of slender foam specimens. The predictions are compared with respective experimental results from literature.
Neutrinos: Theory and Phenomenology
Creators: name: Parke, Stephen J
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The theory and phenomenology of neutrinos will be addressed, especially that relating to the observation of neutrino flavor transformations. The current status and implications for future experiments will be discussed with special emphasis on the experiments that will determine the neutrino mass ordering, the dominant flavor content of the neutrino mass eigenstate with the smallest electron neutrino content and the size of CP violation in the neutrino sector. Beyond the neutrino Standard Model, the evidence for and a possible definitive experiment to confirm or refute the existence of light sterile neutrinos will be briefly discussed.
description: 15 pages, 10 figures, presentation at the "Nobel Symposium on LHC results", May 13-19, 2013 at Krusenberg, Uppsala, Sweden
Paleomagnetism of Miocene volcanics on Sao Tome: Paleosecular variation at the Equator and a comparison to its latitudinal dependence over the last 5 Myr
Creators: name: Opdyke, N. D.
name: Kent, Dennis V.
name: Foster, D. A.
name: Huang, K.
Publisher: name: Columbia University
Year: 2015
Subjects: subject: Geomagnetism
subject: Paleomagnetism
subject: Geophysics
subject: FOS: Earth and related environmental sciences

description: A collection was made in January 2009 of 10 oriented samples from each of 54 sites in lavas on São Tomé Island (nominal location 0.3ºN, 6.5ºE). Some sites were affected by lightning leaving a total of 42 sites for analysis of paleosecular variation. Overall magnetic properties were excellent (highly stable magnetizations carried by pseudosingle domain magnetite). After principal component analysis of progressive alternating field demagnetization data for the samples, 22 sites had normal polarity magnetizations (D = 0. 6º, I = −8.3º, α95 = 4.3º, κ = 53.1) and 20 had reverse magnetizations (D = 176.0º, I = 4.2º, α95 = 7.3º, κ = 20.8); the directions are within 5° of antiparallel, yielding a positive reversal test. The combined data set of 42 site mean virtual geomagnetic poles converted to common (normal) polarity yields a pole position at 86.0°N, 211.5ºE, A95=3.1º. Ar/Ar and K/Ar dating reveals that these rocks are Miocene in age (∼5–11 Ma), old enough to allow northerly plate motion to help explain the slightly far-sided pole position. The between-site dispersion in virtual geomagnetic poles was estimated as the angular standard deviation, Sb, and equaled 11.4° with 95% confidence interval between 9.9° and 13.4°.
Fidelity of optically induced single-spin rotations in semiconductor quantum dots in the presence of nuclear spins
Creators: name: Hildmann, Julia
name: Burkard, Guido
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We examine the influence of nuclear spins on the performance of optically induced rotations of single electron spins in semiconductor quantum dots. We consider Raman type optical transitions between electron spin states and take into account the additional effect of the Overhauser field. We calculate average fidelities of rotations around characteristic axes in the presence of nuclear spins analytically with perturbation theory up to second order in the Overhauser field. Moreover, we calculate the fidelity using numerical averaging over the nuclear field distribution, including arbitrary orders of the hyperfine interaction.
description: 7 pages, 5 figures
Local density of states and particle entanglement in topological quantum fluids
Creators: name: Pu, Songyang
name: Balram, Ajit C.
name: Papić, Zlatko
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The understanding of particle entanglement is an important goal in the studies of correlated quantum matter. The widely-used method of scanning tunneling spectroscopy -- which measures the local density of states (LDOS) of a many-body system by injecting or removing an electron from it -- is expected to be sensitive to particle entanglement. In this paper, we systematically investigate the relation between the particle entanglement spectrum (PES) and the LDOS of fractional quantum Hall (FQH) states, the paradigmatic strongly-correlated phases of electrons with topological order. Using exact diagonalization, we show that the counting of levels in both the LDOS and PES in the Jain sequence of FQH states can be predicted from the composite fermion theory. We point out the differences between LDOS and PES characterization of the bulk quasihole excitations, and we discuss the conditions under which the LDOS counting can be mapped to that of PES. Our results affirm that tunneling spectroscopy is a sensitive tool for identifying the nature of FQH states.
description: 14 pages, 8 figures
Pursuit of new physics within the $Λ_c\to ΔK$ decays
Creators: name: Wang, Di
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We point out the $CP$ asymmetry in the chain decay of $Λ_c^+\to Δ^+K(t)(\to π^+π^-)$ is determined by the branching fractions of $Λ^+_c\to Δ^{++} K^-$, $Λ^+_c\to Δ^{+} K^0_{S,L}$ and $Λ^+_c\to Δ^{0} K^+$ modes under the isospin symmetry. The ambiguities from loop-induced quantities and $SU(3)_F$ breaking hadronic effects are avoided. Once the $CP$ asymmetry in the $Λ_c^+$ decays into $Δ^+$ and neutral kaons is confirmed by experiments, we can check if it is beyond the Standard Model, or verify the $CP$-violating effect resulted from the interference between the Cabibbo-favored and the doubly Cabibbo-suppressed amplitudes with the neutral kaon mixing. Future measurements of branching fractions play a critical role in reducing the uncertainties.
description: 13 pages, 1 figure, published version
Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy
Creators: name: Wang, Huapei
name: Wang, Jun
name: Chen-Wiegart, Yu-Chen Karen
name: Kent, Dennis V.
Publisher: name: Columbia University
Year: 2015
Subjects: Magnetite
Geology, Stratigraphic
Paleoclimatology

description: The Paleocene–Eocene boundary (∼55.8 million years ago) is marked by an abrupt negative carbon isotope excursion (CIE) that coincides with an oxygen isotope decrease interpreted as the Paleocene–Eocene thermal maximum. Biogenic magnetite (Fe3O4) in the form of giant (micron-sized) spearhead-like and spindle-like magnetofossils, as well as nano-sized magnetotactic bacteria magnetosome chains, have been reported in clay-rich sediments in the New Jersey Atlantic Coastal Plain and were thought to account for the distinctive single-domain magnetic properties of these sediments. Uncalibrated strong field magnet extraction techniques have been typically used to provide material for scanning and transmission electron microscopic imaging of these magnetic particles, whose concentration in the natural sediment is thus difficult to quantify. In this study, we use a recently developed ultrahigh-resolution, synchrotron-based, full-field transmission X-ray microscope to study the iron-rich minerals within the clay sediment in their bulk state. We are able to estimate the total magnetization concentration of the giant biogenic magnetofossils to be only ∼10% of whole sediment. Along with previous rock magnetic studies on the CIE clay, we suggest that most of the magnetite in the clay occurs as isolated, near-equidimensional nanoparticles, a suggestion that points to a nonbiogenic origin, such as comet impact plume condensates in what may be very rapidly deposited CIE clays.
title: All That You Say is Beautiful
title: Stories
titleType: Subtitle
Creators: name: Pratt, Omaria Sanchez
Publisher: name: University of Kentucky Libraries
Year: 2019

description: From the city of High Point to New York City, this collection portrays a certain black experience. Through a sociological lens, the stories in All That You Say is Beautiful study intersections of class, race, family, and sexuality by bending forms, expectations, and seeks to understand what it means to be human when your experience is not that of mainstream American culture.
description: Copyright © Omaria Sanchez Pratt 2019
Study of angular observables in exclusive semileptonic $B_c$ decays
Creators: name: Patnaik, Sonali
name: Nayak, Lopamudra
name: Sadangi, Priyanka
name: Swain, Sanjay
name: Singh, Rajeev
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this work, we investigate angular observables such as the longitudinal polarization of charged leptons, $τ$-polarization, and forward-backward asymmetry in semileptonic $B_c$ decays. Additionally, we provide predictions for lepton flavor violating observables, the $\mathcal{R}$ ratios in the decay channels $B_c \rightarrow η_c (J/ψ) l ν_l$ and $B_c \rightarrow D (D^*) l ν_l$ across the entire $q^2$ region. Our analysis is conducted within the Relativistic Independent Quark Model, focusing on the potential model-dependent aspects of these observables. We compare our model predictions with existing lattice predictions, highlighting the strong applicability of our framework in describing $B_c$ decays. Considering the forthcoming experimental upgrades and the Run 3 data results on $B_c$ meson decays, rapid confirmation of these quantities could indicate significant discoveries of physics beyond the Standard Model. This will open up new avenues for understanding the complex flavor dynamics in heavy meson decays.
description: Accepted version in Physical Review D
Automated lattice perturbation theory
Creators: name: Monahan, Christopher
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: I review recent developments in automated lattice perturbation theory. Starting with an overview of lattice perturbation theory, I focus on the three automation packages currently "on the market": HiPPy/HPsrc, Pastor and PhySyCAl. I highlight some recent applications of these methods, particularly in B physics. In the final section I briefly discuss the related, but distinct, approach of numerical stochastic perturbation theory.
description: Plenary talk, 31st International Symposium on Lattice Field Theory, July 29 - August 3, 2013, Mainz, Germany; LaTeX source, 15 pages, 11 figures. Caption to Figure 6 clarified, typos corrected
Unveiling polarized emission from interstellar dust of the Large Magellanic Cloud with Planck
Creators: name: Alina, D.
name: Bernard, J. -Ph.
name: Yuen, K. H.
name: Lazarian, A.
name: Hughes, A.
name: Iskakova, M.
name: Akimkhan, A.
name: Mukanova, A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Polarization of interstellar dust emission is a powerful probe of dust properties and magnetic field structure. Yet studies of external galaxies are hampered by foreground dust contribution. The aim of this study is to separate the polarised signal from the Large Magellanic Cloud (LMC) from that of the Milky Way (MW) in order to construct a wide-field, spatially complete map of dust polarization using the Planck 353 GHz data. To estimate the foreground polarization direction, we used velocity gradients in HI spectral line data and assessed the performance of the output by comparing to starlight extinction polarization. We estimate the foreground intensity using dust properties derived previously from the Planck data and we assume the foreground polarization to be uniform and equal to the average of the MW around the galaxy. After foreground removal, the geometry of the plane-of-the-sky magnetic field in the LMC tends to follow the structure of the atomic gas in the LMC. This is notably the case along the molecular ridges extending south and south-east of the 30 Doradus star-forming complex, and along more diffuse southern arm extending towards the Small Magellanic Cloud. There is also an alignment between the magnetic field and the outer arm in the western part. The median polarization fraction in the LMC is slightly lower than that observed for the MW while the anti-correlation between the polarization angle dispersion function and the polarization fraction is slightly larger. Overall, polarization fraction distribution is similar to that observed in the MW.
description: 15 pages, 22 figures
Efficient approach to two-centre exponential integrals with applications to excited states of molecular hydrogen
Creators: name: Pachucki, Krzysztof
Publisher: name: arXiv
Year: 2013
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: A general approach to evaluation of two-centre two-electron exponential integrals with arbitrary parameters is presented. The results for the Born-Oppenheimer potential for various excited states of molecular hydrogen with Koł os-Wolniewicz functions are obtained with precision exceeding previous values by about 3 orders of magnitude.
description: 17 pages
title: A Population-Based Analysis of Patient Age and Other Disparities in the Treatment of Ovarian Cancer in Central Appalachia and Kentucky
Creators: name: Ore, Robert
Publisher: name: University of Kentucky Libraries
Year: 2019

description: Objectives: Adherence to National Comprehensive Cancer Network (NCCN) guidelines for ovarian cancer treatment improves patient outcomes. The aim of this study was to assess disparities associated with ovarian cancer treatment in the state of Kentucky and central Appalachia.
Methods: Data on patients diagnosed as having ovarian cancer from 2007 through 2011 were extracted from administrative claims-linked Kentucky Cancer Registry data. NCCN compliance was defined by stage, grade, surgical procedure, and chemotherapy. Selection criteria were reviewed carefully to ensure data quality and accuracy. Descriptive analysis, logistic regression, and Cox regression analyses were performed to examine factors associated with guidelines compliance and survival.
Results: Most women were age 65 years or older (62.5%), had high grade (65.9%) and advanced stage (61.0%) ovarian cancer. Two-thirds of cases (65.9%) received NCCN-recommended treatment for ovarian cancer. The hazard ratio (HR) of death for women who did not receive NCCN-compliant care was 62% higher compared to the women who did receive NCCN compliant treatment (HR 1.62, 95% CI 1.11-2.35). Results from the logistic regression showed that NCCN-compliant treatment was more likely for: women age 65-74 years compared to age 20-49 (OR=3.32, 95% CI=1.32- 8.32), late stage compared to early stage cancers (OR 0.32, 95% CI 0.20-0.53), receipt of care at tertiary hospitals (OR=1.92, 95% CI=1.10-3.34), and privately insured compared to Medicaid (OR=0.31, 95% CI=0.13-0.77) or Medicare (OR=0.31, 95% CI=0.15-0.66).
Conclusions: When the treatment of ovarian cancer did not follow NCCN-recommendations, patients had a significantly higher risk of death. Women were less likely to receive NCCN-compliant care if they were of younger age (20-49 years), had early stage disease, were not privately insured, or had care provided at a non-tertiary hospital.
description: Copyright © Robert Ore, 2019
An adaptive GMsFEM for high-contrast flow problems
Creators: name: Chung, Eric T.
name: Efendiev, Yalchin
name: Li, Guanliang
Publisher: name: arXiv
Year: 2013
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: In this paper, we derive an a-posteriori error indicator for the Generalized Multiscale Finite Element Method (GMsFEM) framework. This error indicator is further used to develop an adaptive enrichment algorithm for the linear elliptic equation with multiscale high-contrast coefficients. The GMsFEM, which has recently been introduced in [12], allows solving multiscale parameter-dependent problems at a reduced computational cost by constructing a reduced-order representation of the solution on a coarse grid. The main idea of the method consists of (1) the construction of snapshot space, (2) the construction of the offline space, and (3) the construction of the online space (the latter for parameter-dependent problems). In [12], it was shown that the GMsFEM provides a flexible tool to solve multiscale problems with a complex input space by generating appropriate snapshot, offline, and online spaces. In this paper, we study an adaptive enrichment procedure and derive an a-posteriori error indicator which gives an estimate of the local error over coarse grid regions. We consider two kinds of error indicators where one is based on the $L^2$-norm of the local residual and the other is based on the weighted $H^{-1}$-norm of the local residual where the weight is related to the coefficient of the elliptic equation. We show that the use of weighted $H^{-1}$-norm residual gives a more robust error indicator which works well for cases with high contrast media. The convergence analysis of the method is given. In our analysis, we do not consider the error due to the fine-grid discretization of local problems and only study the errors due to the enrichment. Numerical results are presented that demonstrate the robustness of the proposed error indicators.
description: 26 pages
Weaker axially dipolar time-averaged paleomagnetic field based on multidomain-corrected paleointensities from Galapagos lavas
Creators: name: Wang, Huapei
name: Kent, Dennis V.
name: Rochette, Pierre
Publisher: name: Columbia University
Year: 2015
Subjects: subject: Geomagnetism
subject: Paleomagnetism
subject: Geophysics
subject: FOS: Earth and related environmental sciences

description: The geomagnetic field is predominantly dipolar today, and high-fidelity paleomagnetic mean directions from all over the globe strongly support the geocentric axial dipole (GAD) hypothesis for the past few million years. However, the bulk of paleointensity data fails to coincide with the axial dipole prediction of a factor-of-2 equator-to-pole increase in mean field strength, leaving the core dynamo process an enigma. Here, we obtain a multidomain-corrected Pliocene–Pleistocene average paleointensity of 21.6 ± 11.0 µT recorded by 27 lava flows from the Galapagos Archipelago near the Equator. Our new result in conjunction with a published comprehensive study of single-domain–behaved paleointensities from Antarctica (33.4 ± 13.9 µT) that also correspond to GAD directions suggests that the overall average paleomagnetic field over the past few million years has indeed been dominantly dipolar in intensity yet only ∼60% of the present-day field strength, with a long-term average virtual axial dipole magnetic moment of the Earth of only 4.9 ± 2.4 × 10²² A⋅m².
AN ANALYSIS OF STUDENTS SATISFACTION LEVEL ABOUT THE QUALITY OF EDUCATION IN THE WOMAN UNIVERSITY MULTAN
Creators: name: Saira Banoo
Publisher: name: figshare
Year: 2020
Subjects: subject: Developmental and Educational Psychology
subject: 130306 Educational Technology and Computing
subject: FOS: Educational sciences
subject: 200401 Applied Linguistics and Educational Linguistics
subject: FOS: Languages and literature
subject: 170103 Educational Psychology
subject: FOS: Psychology
subject: 130305 Educational Counselling
subject: 130304 Educational Administration, Management and Leadership
subject: 130310 Maori Education (excl. Early Childhood and Primary Education)
subject: Education
subject: 130106 Secondary Education
subject: 160809 Sociology of Education
subject: FOS: Sociology
subject: 130199 Education systems not elsewhere classified
subject: 160506 Education Policy
subject: FOS: Political science
subject: 130313 Teacher Education and Professional Development of Educators
subject: 130103 Higher Education

description: Universities in the modern world are expected to seek and cultivate new knowledge, provide the right kind of leadership and strive to promote equality and social justice. The quality of education is an important factor considered for attracting and retaining students as it a substantial investment made by their partents. Hence delivering quality service has become an important goal for most higher education institutions (HEIs) and for distinguishing the institutions among other competitors. The general objective of the study is to investigate the satisfaction level of student enrolled in undergraduate, graduate and post graduate programs from the Women University Multan. The level of service quality with respect to administrative service, support facilities, physical environmental quality, and transformative quality and overall level of students satisfaction in all university service. The study design was conducted on students of the women university selected using a random sampling technique. Data was collected from 300 Questionnaire and analyzed through SPSS. By using analysis, Anova,T test and Pearson correlation of coefficient was used. Major findings of study revealed that there was a significant relationship between students satisfaction and quality of education.
Improved bounds for the bracketing number of orthants or revisiting an algorithm of Thiémard to compute bounds for the star discrepancy
Creators: name: Gnewuch, Michael
Publisher: name: arXiv
Year: 2024
Subjects: subject: Combinatorics (math.CO)
subject: Computational Geometry (cs.CG)
subject: Discrete Mathematics (cs.DM)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: We improve the best known upper bound for the bracketing number of $d$-dimensional axis-parallel boxes anchored in $0$ (or, put differently, of lower left orthants intersected with the $d$-dimensional unit cube $[0,1]^d$). More precisely, we provide a better upper bound for the cardinality of an algorithmic bracketing cover construction due to Eric Thiémard, which forms the core of his algorithm to approximate the star discrepancy of arbitrary point sets from [E. Thiémard, An algorithm to compute bounds for the star discrepancy, J.~Complexity 17 (2001), 850 -- 880].
 Moreover, the new upper bound for the bracketing number of anchored axis-parallel boxes yields an improved upper bound for the bracketing number of arbitrary axis-parallel boxes in $[0,1]^d$.
 In our upper bounds all constants are fully explicit.
description: 13 pages, to appear in Journal of Complexity
BrainGB: A Benchmark for Brain Network Analysis with Graph Neural Networks
Creators: name: Cui, Hejie
name: Dai, Wei
name: Zhu, Yanqiao
name: Kan, Xuan
name: Gu, Antonio Aodong Chen
name: Lukemire, Joshua
name: Zhan, Liang
name: He, Lifang
name: Guo, Ying
name: Yang, Carl
Publisher: name: arXiv
Year: 2022
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: Machine Learning (cs.LG)
subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Biological sciences
subject: FOS: Computer and information sciences

description: Mapping the connectome of the human brain using structural or functional connectivity has become one of the most pervasive paradigms for neuroimaging analysis. Recently, Graph Neural Networks (GNNs) motivated from geometric deep learning have attracted broad interest due to their established power for modeling complex networked data. Despite their superior performance in many fields, there has not yet been a systematic study of how to design effective GNNs for brain network analysis. To bridge this gap, we present BrainGB, a benchmark for brain network analysis with GNNs. BrainGB standardizes the process by (1) summarizing brain network construction pipelines for both functional and structural neuroimaging modalities and (2) modularizing the implementation of GNN designs. We conduct extensive experiments on datasets across cohorts and modalities and recommend a set of general recipes for effective GNN designs on brain networks. To support open and reproducible research on GNN-based brain network analysis, we host the BrainGB website at https://braingb.us with models, tutorials, examples, as well as an out-of-box Python package. We hope that this work will provide useful empirical evidence and offer insights for future research in this novel and promising direction.
description: IEEE Transactions on Medical Imaging
Majorana states in helical Shiba chains and ladders
Creators: name: Pöyhönen, Kim
name: Westström, Alex
name: Röntynen, Joel
name: Ojanen, Teemu
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Motivated by recent proposals to realize Majorana bound states in chains and arrays of magnetic atoms deposited on top of a superconductor, we study the topological properties of various chain structures, ladders and two-dimensional arrangements exhibiting magnetic helices. We show that magnetic domain walls where the chirality of a magnetic helix is inverted support two protected Majorana states giving rise to a tunneling conductance peak twice the height of a single Majorana state. The topological properties of coupled chains exhibit nontrivial behaviour as a function of the number of chains beyond the even-odd dichotomy expected from the simple $\mathbb{Z}_2$ nature of coupled Majorana states. In addition, it is possible that a ladder of two or more coupled chains exhibit Majorana edge states even when decoupled chains are trivial. We formulate a general criterion for the number of Majorana edge states in multichain ladders and discuss some experimental consequences of our findings.
description: 6 pages, 7 Figs
Prenatal Polycyclic Aromatic Hydrocarbon, Adiposity, Peroxisome Proliferator-Activated Receptor (PPAR) γ Methylation in Offspring, Grand-Offspring Mice
Creators: name: Yan, Zhonghai
name: Zhang, Hanjie
name: Maher, Christina
name: Arteaga-Solis, Emilio
name: Champagne, Frances Anne
name: Wu, Licheng
name: McDonald, Jacob D.
name: Yan, Beizhan
name: Schwartz, Gary J.
name: Miller, Rachel L.
Publisher: name: Columbia University
Year: 2014
Subjects: Prenatal influences
Obesity--Genetic aspects
Polycyclic aromatic hydrocarbons
Molecular biology
Developmental biology
Epidemiology

description: Rationale Greater levels of prenatal exposure to polycyclic aromatic hydrocarbon (PAH) have been associated with childhood obesity in epidemiological studies. However, the underlying mechanisms are unclear. Objectives We hypothesized that prenatal PAH over-exposure during gestation would lead to weight gain and increased fat mass in offspring and grand-offspring mice. Further, we hypothesized that altered adipose gene expression and DNA methylation in genes important to adipocyte differentiation would be affected. Materials and Methods Pregnant dams were exposed to a nebulized PAH mixture versus negative control aerosol 5 days a week, for 3 weeks. Body weight was recorded from postnatal day (PND) 21 through PND60. Body composition, adipose cell size, gene expression of peroxisome proliferator-activated receptor (PPAR) γ, CCAAT/enhancer-binding proteins (C/EBP) α, cyclooxygenase (Cox)-2, fatty acid synthase (FAS) and adiponectin, and DNA methylation of PPAR γ, were assayed in both the offspring and grand-offspring adipose tissue. Findings Offspring of dams exposed to greater PAH during gestation had increased weight, fat mass, as well as higher gene expression of PPAR γ, C/EBP α, Cox2, FAS and adiponectin and lower DNA methylation of PPAR γ. Similar differences in phenotype and DNA methylation extended through the grand-offspring mice. Conclusions Greater prenatal PAH exposure was associated with increased weight, fat mass, adipose gene expression and epigenetic changes in progeny.
Carbon and Oxygen Abundances in Cool Metal-rich Exoplanet Hosts: A Case Study of the C/O Ratio of 55 Cancri
Creators: name: Teske, Johanna K.
name: Cunha, Katia
name: Schuler, Simon C.
name: Griffith, Caitlin A.
name: Smith, Verne V.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The super-Earth exoplanet 55 Cnc e, the smallest member of a five-planet system, has recently been observed to transit its host star. The radius estimates from transit observations, coupled with spectroscopic determinations of mass, provide constraints on its interior composition. The composition of exoplanetary interiors and atmospheres are particularly sensitive to elemental C/O ratio, which to first order can be estimated from the host stars. Results from a recent spectroscopic study analyzing the 6300A [O I] line and two C I lines suggest that 55 Cnc has a carbon-rich composition (C/O=1.12+/-0.09). However oxygen abundances derived using the 6300A [O I] line are highly sensitive to a Ni I blend, particularly in metal-rich stars such as 55 Cnc ([Fe/H]=0.34+/-0.18). Here, we further investigate 55 Cnc's composition by deriving the carbon and oxygen abundances from these and additional C and O absorption features. We find that the measured C/O ratio depends on the oxygen lines used. The C/O ratio that we derive based on the 6300A [O I] line alone is consistent with the previous value. Yet, our investigation of additional abundance indicators results in a mean C/O ratio of 0.78+/-0.08. The lower C/O ratio of 55 Cnc determined here may place this system at the sensitive boundary between protoplanetary disk compositions giving rise to planets with high (>0.8) versus low (<0.8) C/O ratios. This study illustrates the caution that must applied when determining planet host star C/O ratios, particularly in cool, metal-rich stars.
description: Accepted in ApJ; 22 pages in preprint style, 4 tables, 2 figures
Debye temperature, electron-phonon coupling constant, and three-dome shape of crystalline strain as a function of pressure in highly compressed La$_3$Ni$_2$O$_{7-δ}$
Creators: name: Talantsev, E. F.
name: Chistyakov, V. V.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Besides ongoing studies of phase structural transitions, pairing mechanism, and physical properties of recently discovered highly compressed high-temperature superconductor La$_3$Ni$_2$O$_{7-δ}$, here we explored a possibility for the electron-phonon pairing mechanism as an origin of the superconducting state and determined the microcrystalline strain, $ε(P)$, in high pressure $Fmmm$-phase, and low-pressure $Ammm$-phase of this nickelate. To do this, we analyzed temperature dependent resistance and extracted pressure dependent Debye temperature, $Θ_D(P)$, in La$_3$Ni$_2$O$_{7-δ}$ with an approximate value of $Θ_D(P = 25 GPa) = 550$ $K$. From this we established that the La$_3$Ni$_2$O$_{7-δ}$ is strong-coupled superconductor with the electron-phonon coupling constant $λ_{e-ph}(P=22.4 GPa) = 1.75$. This value is close to $λ_{e-ph} = 1.70$ of ambient pressure superconductors $Nb_3R (R = Sn, Al)$. To address ongoing discussion that the lattice strain can be the origin for the emergence of high-temperature superconductivity in the La$_3$Ni$_2$O$_{7-δ}$, we determined the microcrystalline strain, $0.011 < ε(P)$, in the high-pressure $Fmmm$-phase, and $ε(P) < 0.011$ of low-pressure $Fmmm$-phase. Our analysis showed that $ε(P)$ has three-dome shape in the pressure range of $1.6 GPa < P < 41.2 GPa$. One of these two $ε(P)$ deeps at $P \approx 15 GPa$ coincides with the pressure at which the $Ammm$-phase into the $Fmmm$-phase phase transition occurs. Based on our analysis, we proposed probable condition to observe the zero-resistance state in La$_3$Ni$_2$O$_{7-δ}$.
description: 11 pages, 5 figures, 62 references and Supplementary Information
The Koslowski- Sahlmann representation: Gauge and diffeomorphism invariance
Creators: name: Campiglia, Miguel
name: Varadarajan, Madhavan
Publisher: name: arXiv
Year: 2013
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The discrete spatial geometry underlying Loop Quantum Gravity (LQG) is degenerate almost everywhere. This is at apparent odds with the non- degeneracy of asymptotically flat metrics near spatial infinity. Koslowski generalised the LQG representation so as to describe states labelled by smooth non- degenerate triad fields. His representation was further studied by Sahlmann with a view to imposing gauge and spatial diffeomorphism invariance through group averaging methods. Motivated by the desire to model asymptotically flat quantum geometry by states with triad labels which are non- degenerate at infinity but not necessarily so in the interior, we initiate a generalisation of Sahlmann's considerations to triads of varying degeneracy. In doing so, we include delicate phase contributions to the averaging procedure which are crucial for the correct implementation of the gauge and diffeomorphism constraints, and whose existence can be traced to the background exponential functions recently constructed by one of us. Our treatment emphasizes the role of symmetries of quantum states in the averaging procedure. Semianalyticity, influential in the proofs of the beautiful uniqueness results for LQG, plays a key role in our considerations. As a by product, we re- derive the group averaging map for standard LQG, highlighting the role of state symmetries and explicitly exhibiting the essential uniqueness of its specification.
Exponential-Krylov methods for ordinary differential equations
Creators: name: Tranquilli, Paul
name: Sandu, Adrian
Publisher: name: arXiv
Year: 2014
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: This paper develops a new class of exponential-type integrators where all the matrix exponentiations are performed in a single Krylov space of low dimension. The new family, called Lightly Implicit Krylov-Exponential (LIKE), is well suited for solving large scale systems of ODEs or semi-discrete PDEs. The time discretization and the Krylov space approximation are treated as a single computational process, and the Krylov space properties are an integral part of the new LIKE order condition theory developed herein. Consequently, LIKE methods require a small number of basis vectors determined solely by the temporal order of accuracy. The subspace size is independent of the ODE under consideration, and there is no need to monitor the errors in linear system solutions at each stage. Numerical results illustrate the favorable properties of new family of methods.