cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Protostellar outflows with Smoothed Particle Magnetohydrodynamics (SPMHD)
Creators: name: Bürzle, Florian
name: Clark, Paul C.
name: Stasyszyn, Federico
name: Dolag, Klaus
name: Klessen, Ralf S.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The protostellar collapse of a molecular cloud core is usually accompanied by outflow phenomena. The latter are thought to be driven by magnetorotational processes from the central parts of the protostellar disc. While several 3D AMR/nested grid studies of outflow phenomena in collapsing magnetically supercritical dense cores have been reported in the literature, so far no such simulation has been performed using the Smoothed Particle Hydrodynamics (SPH) method. This is mainly due to intrinsic numerical difficulties in handling magnetohydrodynamics within SPH, which only recently were partly resolved. In this work, we use an approach where we evolve the magnetic field via the induction equation, augmented with stability correction and divergence cleaning schemes. We consider the collapse of a rotating core of one solar mass, threaded by a weak magnetic field initially parallel to the rotation axis so that the core is magnetically supercritical. We show, that Smoothed Particle Magnetohydrodynamics (SPMHD) is able to handle the magnetorotational processes connected with outflow phenomena, and to produce meaningful results which are in good agreement with findings reported in the literature. Especially, our numerical scheme allows for a quantitative analysis of the evolution of the ratio of the toroidal to the poloidal magnetic field, which we performed in this work.
description: 5 pages, 4 figures. Accepted to MNRAS Letters
Globally time-reversible fluid simulations with smoothed particle hydrodynamics
Creators: name: Kincl, Ondrej
name: Pavelka, Michal
Publisher: name: arXiv
Year: 2022
Subjects: subject: Numerical Analysis (math.NA)
subject: Symplectic Geometry (math.SG)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: This paper describes an energy-preserving and globally time-reversible code for weakly compressible smoothed particle hydrodynamics (SPH). We do not add any additional dynamics to the Monaghan's original SPH scheme at the level of ordinary differential equation, but we show how to discretize the equations by using a corrected expression for density and by invoking a symplectic integrator. Moreover, to achieve the global-in-time reversibility, we have to correct the initial state, implement a conservative fluid-wall interaction, and use the fixed-point arithmetic. Although the numerical scheme is reversible globally in time (solvable backwards in time while recovering the initial conditions), we observe thermalization of the particle velocities and growth of the Boltzmann entropy. In other words, when we do not see all the possible details, as in the Boltzmann entropy, which depends only on the one-particle distribution function, we observe the emergence of the second law of thermodynamics (irreversible behavior) from purely reversible dynamics.
description: Submitted to a journal
Scotogenic Dirac neutrino mass models embedded with leptoquarks: one pathway to address the flavor anomalies and the neutrino masses together
Creators: name: Li, Shao-Ping
name: Li, Xin-Qiang
name: Yan, Xin-Shuai
name: Yang, Ya-Dong
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: If the leptoquarks proposed to account for the intriguing anomalies observed in the $B$-meson decays, $R_{D^{(\ast)}}$ and $R_{K^{(\ast)}}$, as well as in the anomalous magnetic moment of the muon, $(g-2)_μ$, can be embedded into the scotogenic Dirac neutrino model, all these flavor anomalies, together with the origin of neutrino masses and the nature of dark matter, would be potentially addressed in a unified picture. Among the minimal seesaw, one-loop, and two-loop realizations of the dimension-4 effective operator $\mathcal{L}_{4}$ for the Dirac neutrino masses, we show that plenty of diagrams associated with the two-loop realizations of $\mathcal{L}_{4}$ can support the coexistence of leptoquarks and dark matter candidates. After a simple match of these leptoquarks to those that can accommodate all the flavor anomalies, we establish the scotogenic Dirac neutrino models embedded with leptoquarks, which could address all the problems mentioned above.
description: 15 pages, 16 tables, 9 figures
High fidelity state preparation, quantum control, and readout of an isotopically enriched silicon spin qubit
Creators: name: Mills, A. R.
name: Guinn, C. R.
name: Feldman, M. M.
name: Sigillito, A. J.
name: Gullans, M. J.
name: Rakher, M.
name: Kerckhoff, J.
name: Jackson, C. A. C.
name: Petta, J. R.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Quantum systems must be prepared, controlled, and measured with high fidelity in order to perform complex quantum algorithms. Control fidelities have greatly improved in silicon spin qubits, but state preparation and readout fidelities have generally been poor. By operating with low electron temperatures and employing high-bandwidth cryogenic amplifiers, we demonstrate single qubit readout visibilities >99%, exceeding the threshold for quantum error correction. In the same device, we achieve average single qubit control fidelities >99.95%. Our results show that silicon spin qubits can be operated with high overall operation fidelity.
Collective modes of gluons in an anisotropic thermo-magnetic medium
Creators: name: Karmakar, Bithika
name: Ghosh, Ritesh
name: Mukherjee, Arghya
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We study the collective modes of gluons in an anisotropic thermal medium in the presence of a constant background magnetic field using the hard-thermal loop (HTL) perturbation theory. The momentum space anisotropy of the medium has been incorporated through the generalized $`$Romatschke-Strickland' form of the distribution function, whereas, the magnetic modification arising from the quark loop contribution has been taken into account in the lowest Landau level approximation. We consider two special cases: (i) a spheroidal anisotropy with the anisotropy vector orthogonal to the external magnetic field and (ii) an ellipsoidal anisotropy with two mutually orthogonal vectors describing aniostropies along and orthogonal to the field direction. The general structure of the polarization tensor in both cases are equivalent and consists of six independent basis tensors. We find that the introduction of momentum anisotropy ingrains azimuthal angular dependence in the thermo-magnetic collective modes. Our study suggests that the presence of a strong background magnetic field can significantly reduce the growth rate of the unstable modes which may have important implications in the equilibration of magnetized quark-gluon plasma.
description: 17 pages, 7 figures, Accepted in Physical Review D
Spin-momentum locking from topological quantum chemistry: applications to multifold fermions
Creators: name: Lin, Mao
name: Robredo, Iñigo
name: Schröter, Niels B. M.
name: Felser, Claudia
name: Vergniory, Maia G.
name: Bradlyn, Barry
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In spin-orbit coupled crystals, symmetries can protect multifold degeneracies with large Chern numbers and Brillouin zone spanning topological surface states. In this work, we explore the extent to which the nontrivial topology of chiral multifold fermions impacts the spin texture of bulk states. To do so, we formulate a definition of spin-momentum locking in terms of reduced density matrices. Using tools from the theory of topological quantum chemistry, we show how the reduced density matrix can be determined from the knowledge of the basis orbitals and band representation forming the multifold fermion. We show how on-site spin orbit coupling, crystal field splitting, and Wyckoff position multiplicity compete to determine the spin texture of states near chiral fermions. We compute the spin texture of multifold fermions in several representative examples from space groups $P432$ (207) and $P2_13$ (198). We show that the winding number of the spin around the Fermi surface can take many different integer values, from zero all the way to $\pm 7$. Finally, we conclude by showing how to apply our theory to real materials using the example of PtGa in space group $P2_13$.
description: 28 pages, 6 figures
Discussion of "Feature Matching in Time Series Modeling" by Y. Xia and H. Tong
Creators: name: Ionides, Edward L.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Discussion of "Feature Matching in Time Series Modeling" by Y. Xia and H. Tong [arXiv:1104.3073]
description: Published in at http://dx.doi.org/10.1214/11-STS345C the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Celestial Amplitudes as AdS-Witten Diagrams
Creators: name: Casali, Eduardo
name: Melton, Walker
name: Strominger, Andrew
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Both celestial and momentum space amplitudes in four dimensions are beset by divergences resulting from spacetime translation and sometimes scale invariance. In this paper we consider a (linearized) marginal deformation of the celestial CFT for Yang-Mills theory which preserves 2D conformal invariance but breaks both spacetime translation and scale invariance and involves a chirally coupled massive scalar. The resulting celestial amplitudes are completely finite (apart from the usual soft and collinear divergences) and take the canonical CFT form. Moreover, we show they can be simply rewritten in terms of AdS$_3$-Witten contact diagrams which evaluate to the well-known $D$-functions, thereby forging a direct connection between flat and AdS holography.
description: 16 pages, 3 figures. Version to appear in the Journal of High Energy Physics
A full degree-of-freedom photonic crystal spatial light modulator
Creators: name: Panuski, Christopher L.
name: Christen, Ian R.
name: Minkov, Momchil
name: Brabec, Cole J.
name: Trajtenberg-Mills, Sivan
name: Griffiths, Alexander D.
name: McKendry, Jonathan J. D.
name: Leake, Gerald L.
name: Coleman, Daniel J.
name: Tran, Cung
name: Louis, Jeffrey St
name: Mucci, John
name: Horvath, Cameron
name: Westwood-Bachman, Jocelyn N.
name: Preble, Stefan F.
name: Dawson, Martin D.
name: Strain, Michael J.
name: Fanto, Michael L.
name: Englund, Dirk R.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Harnessing the full complexity of optical fields requires complete control of all degrees-of-freedom within a region of space and time -- an open goal for present-day spatial light modulators (SLMs), active metasurfaces, and optical phased arrays. Here, we solve this challenge with a programmable photonic crystal cavity array enabled by four key advances: (i) near-unity vertical coupling to high-finesse microcavities through inverse design, (ii) scalable fabrication by optimized, 300 mm full-wafer processing, (iii) picometer-precision resonance alignment using automated, closed-loop "holographic trimming", and (iv) out-of-plane cavity control via a high-speed micro-LED array. Combining each, we demonstrate near-complete spatiotemporal control of a 64-resonator, two-dimensional SLM with nanosecond- and femtojoule-order switching. Simultaneously operating wavelength-scale modes near the space- and time-bandwidth limits, this work opens a new regime of programmability at the fundamental limits of multimode optical control.
description: 25 pages, 20 figures
Regime variance testing - a quantile approach
Creators: name: gajda, Janusz
name: Sikora, Grzegorz
name: Wyłomańska, Agnieszka
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: This paper is devoted to testing time series that exhibit behavior related to two or more regimes with different statistical properties. Motivation of our study are two real data sets from plasma physics with observable two-regimes structure. In this paper we develop estimation procedure for critical point of division the structure change of a time series. Moreover we propose three tests for recognition such specific behavior. The presented methodology is based on the empirical second moment and its main advantage is lack of the distribution assumption. Moreover, the examined statistical properties we express in the language of empirical quantiles of the squared data therefore the methodology is an extension of the approach known from the literature. The theoretical results we confirm by simulations and analysis of real data of turbulent laboratory plasma.
Maternal and Neonatal Risk Factors of Low Birth Weight in Guwahati Metro, Assam, Northeast India: A Cross Sectional Study
Creators: name: Nirmali Gogoi
Publisher: name: Zenodo
Year: 2021
Subjects: Low birth weight
maternal age
parity
ANC visit
HB% level
gestational age
high risk behavior
GMCH

description: Introduction and Objectives: Birth weight is an important determinant of child survival and development. Low birth weight is an index of our status of public health, maternal health and nutrition. The major challenge in the field of public health is to identify the factors influencing low birth weight and to institute remedial measures. The study was attempted to assess prevalence of low birth weight and its risk factors affecting low birth weight was conducted among 300 mothers and their respective live born baby in GMCH, Guwahati metro, Assam. Materials and Methods: A cross sectional study design was carried out in a government hospital among 300 mothers using interviewer administered questionnaire. All 300 postnatal mothers who delivered in the hospital during study period were included in the study except still births. All babies were weighted on standard beam balance within 24 hours of delivery and mother’s height was measured by height measuring stand. Bivariate and multivariate logistic regression was employed to identify the predictors at p<0.001 and p<0.05. Results and Analysis: The prevalence of low birth weight was found as 26.0% (95%, CL=21.36-31.24) in 300 samples. 50% of LBW was found in the age group of mothers <18 yrs. Low birth weight was significantly risk with maternal age <18 years (OR=3.06* 95%Cl=1.24-3.52), height of the mother <145 cm (OR=2.72* 95%CL=1.61-4.62), history of ANC visit <3(OR=1.90* 95% Cl=1.03-3.52), multiple pregnancy (OR=5.95* 95% Cl=1.07-33.13), gestational age <37weeks (OR=10.00*15 95% Cl=4.53-22.09). Female child (OR=1.02, 95% Cl=0.61-1.72) and preterm birth (OR=10.00, 95%Cl=4.53-22.09), weight gain during pregnancy <6 kg (OR=1.98 95%Cl=0.88-4.44), history of high risk behavior(use of tobacco) (OR=8.84 95%Cl=0.91-86.28), iron and folic acid consumption (OR=1.44, 95%CI: 0.35-5.90), status of previous birth (OR=2.73, 95%CI: 0.81-9.14), were found to be higher risk of LBW. Discussion and Conclusion: The prevalence of low birth weight was found to be very high and it was associated with many risk factors related to maternal health and services. Hence it is recommended to improve maternal health through strengthening the existing maternal services at the basic level of community.
A Uniform Search for Secondary Eclipses of Hot Jupiters in Kepler Q2 Lightcurves
Creators: name: Coughlin, Jeffrey L.
name: Lopez-Morales, Mercedes
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present the results of searching the Kepler Q2 public dataset for the secondary eclipses of 76 hot Jupiter planet candidates from the list of 1,235 candidates published by Borucki et al. (2011). This search has been performed by modeling both the Kepler PDC light curves and new light curves produced via our own photometric pipeline. We derive new stellar and planetary parameters for each system with robust errors. We find 16 systems with 1-2 sigma, 14 systems with 2-3 sigma, and 6 systems with >3 sigma confidence level secondary eclipse detections in at least one light curve. We find that the majority of detected planet candidates emit more light than expected due to thermal blackbody emission in the optical Kepler bandpass, and present a trend of increasing excess emission with decreasing maximum effective planetary temperature. We explore modeling biases, significant planetary albedos, non-LTE or other thermal emission, significant internal energy generation, and exoplanet mis-identification as possible causes of both the excess emission and its correlation with expected planetary temperature. Although we find no single cause is able to explain all of the planet candidates, significant planetary albedos, with a general trend of increasing planetary albedos with decreasing atmospheric temperatures, is able to explain most of the systems. We estimate an 11% false positive rate in the current Kepler planet candidate sample of hot Jupiters. We also establish robust upper limits on the eclipse depth for all systems, and find that a significant fraction of these systems have very low albedos, significantly augmenting and extending the sample of albedo determinations to planets as cool as 1200 K. Finally, we note that continued observations with Kepler, and improved techniques for the removal of systematic noise in the Kepler data, are needed to better characterize these systems.
description: 33 pages, 9 figures, 3 tables. Submitted to the Astronomical Journal 9/13/2011. Accepted 12/4/2011
Creative Problem Solving in Artificially Intelligent Agents: A Survey and Framework
Creators: name: Gizzi, Evana
name: Nair, Lakshmi
name: Chernova, Sonia
name: Sinapov, Jivko
Publisher: name: arXiv
Year: 2022
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Creative Problem Solving (CPS) is a sub-area within Artificial Intelligence (AI) that focuses on methods for solving off-nominal, or anomalous problems in autonomous systems. Despite many advancements in planning and learning, resolving novel problems or adapting existing knowledge to a new context, especially in cases where the environment may change in unpredictable ways post deployment, remains a limiting factor in the safe and useful integration of intelligent systems. The emergence of increasingly autonomous systems dictates the necessity for AI agents to deal with environmental uncertainty through creativity. To stimulate further research in CPS, we present a definition and a framework of CPS, which we adopt to categorize existing AI methods in this field. Our framework consists of four main components of a CPS problem, namely, 1) problem formulation, 2) knowledge representation, 3) method of knowledge manipulation, and 4) method of evaluation. We conclude our survey with open research questions, and suggested directions for the future.
description: 46 pages (including appendix), 17 figures, under submission at Journal of Artificial Intelligence Research (JAIR)
title: Bidirectional system on chip for intracorporeal pressure measurement
title: Bidirektionale System on Chip zur Intrakorporalen Druckmessung
titleType: AlternativeTitle
Creators: name: Bradford, Bryce Theron
Publisher: name: TUHH Universitätsbibliothek
Year: 2014
Subjects: subject: CMOS
subject: Drahtlose Energie
subject: PLL Noise Analysis
subject: CMOS nanoelectronics
subject: wireless power
subject: PLL noise analysis
subject: CMOS
subject: Phasenregelkreis

description: Ein Mehrkanal Druckersensor mit Drahtlose Energie und Daten Sendung und drahtlose Datenübertragung zum Messen des Blutdrucks mit einem kapazitiven Drucksensor. Das ganze System integrierte auf ein anwendungsspezifische integrierte Schaltung, und ausgeführt mit 130nm CMOS Technologie.
description: A multichannel pressure sensing integrated circuit utilizing wireless power and wireless data transmission for measuring blood pressure using a capacitive pressure sensor. The entire system is integrated onto an application specific integrated circuit designed using 130nm CMOS technology.
Effect of Wigner rotation on estimating unitary-shift parameter of relativistic spin-1/2 particle
Creators: name: Funada, Shin
name: Suzuki, Jun
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We obtain the accuracy limit for estimating the expectation value of the position of a relativistic particle for an observer moving along one direction at a constant velocity. We use a specific model of a relativistic spin-1/2 particle described by a gaussian wave function with a spin down in the rest frame. To derive the state vector of the particle for the moving observer, we use the Wigner rotation that entangles the spin and the momentum of the particle. Based on this wave function for the moving frame, we obtain the symmetric logarithmic derivative (SLD) Cramer-Rao bound that sets the estimation accuracy limit for an arbitrary moving observer. It is shown that estimation accuracy decreases monotonically in the velocity of the observer when the moving observer does not measure the spin degree of freedom. This implies that the estimation accuracy limit worsens with increasing the observer's velocity, but it is finite even in the relativistic limit. We derive the amount of this information loss by the exact calculation of the SLD Fisher information matrix in an arbitrary moving frame.
Staying the course: Locating equilibria of dynamical systems on Riemannian manifolds defined by point-clouds
Creators: name: Bello-Rivas, Juan M.
name: Georgiou, Anastasia
name: Guckenheimer, John
name: Kevrekidis, Ioannis G.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Numerical Analysis (math.NA)
subject: Differential Geometry (math.DG)
subject: Dynamical Systems (math.DS)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: 37M05, 53Z50, 65L99

description: We introduce a method to successively locate equilibria (steady states) of dynamical systems on Riemannian manifolds. The manifolds need not be characterized by an a priori known atlas or by the zeros of a smooth map. Instead, they can be defined by point-clouds and sampled as needed through an iterative process. If the manifold is an Euclidean space, our method follows isoclines, curves along which the direction of the vector field $X$ is constant. For a generic vector field $X$, isoclines are smooth curves and every equilibrium lies on isoclines. We generalize the definition of isoclines to Riemannian manifolds through the use of parallel transport: generalized isoclines are curves along which the directions of $X$ are parallel transports of each other. As in the Euclidean case, generalized isoclines of generic vector fields $X$ are smooth curves that connect equilibria of $X$. Our algorithm can be regarded as an extension of the method of Newton trajectories to the manifold setting when the manifold is unknown. This work is motivated by computational statistical mechanics, specifically high dimensional (stochastic) differential equations that model the dynamics of molecular systems. Often, these dynamics concentrate near low-dimensional manifolds and have transitions (saddle points with a single unstable direction) between metastable equilibria. We employ iteratively sampled data and isoclines to locate these saddle points. Coupling a black-box sampling scheme (e.g., Markov chain Monte Carlo) with manifold learning techniques (diffusion maps in the case presented here), we show that our method reliably locates equilibria of $X$.
Ito-Wiener chaos and the Hodge decomposition on an abstract Wiener space
Creators: name: Yang, Yuxin
Publisher: name: arXiv
Year: 2011
Subjects: subject: Probability (math.PR)
subject: General Topology (math.GN)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 58A14, 58A12, 58B05, 20C35, 60H30

description: Using the structure of the Boson-Fermion Fock space and an argument taken from [2], we give a new proof of the triviality of the $L^2$ cohomology groups on an abstract Wiener space, alternative to that given by Shigekawa [9]. We apply some representation theory of the symmetric group to characterise the spaces of exact and co-exact forms in their Boson-Fermion Fock space representation.
Denoising of Three-Dimensional Fast Spin Echo Magnetic Resonance Images of Knee Joints using Spatial-Variant Noise-Relevant Residual Learning of Convolution Neural Network
Creators: name: Zhao, Shutian
name: Cahill, Donal G.
name: Li, Siyue
name: Xiao, Fan
name: Blu, Thierry
name: Griffith, James F
name: Chen, Weitian
Publisher: name: arXiv
Year: 2022
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: Medical Physics (physics.med-ph)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Two-dimensional (2D) fast spin echo (FSE) techniques play a central role in the clinical magnetic resonance imaging (MRI) of knee joints. Moreover, three-dimensional (3D) FSE provides high-isotropic-resolution magnetic resonance (MR) images of knee joints, but it has a reduced signal-to-noise ratio compared to 2D FSE. Deep-learning denoising methods are a promising approach for denoising MR images, but they are often trained using synthetic noise due to challenges in obtaining true noise distributions for MR images. In this study, inherent true noise information from 2-NEX acquisition was used to develop a deep-learning model based on residual learning of convolutional neural network (CNN), and this model was used to suppress the noise in 3D FSE MR images of knee joints. The proposed CNN used two-step residual learning over parallel transporting and residual blocks and was designed to comprehensively learn real noise features from 2-NEX training data. The results of an ablation study validated the network design. The new method achieved improved denoising performance of 3D FSE knee MR images compared with current state-of-the-art methods, based on the peak signal-to-noise ratio and structural similarity index measure. The improved image quality after denoising using the new method was verified by radiological evaluation. A deep CNN using the inherent spatial-varying noise information in 2-NEX acquisitions was developed. This method showed promise for clinical MRI assessments of the knee, and has potential applications for the assessment of other anatomical structures.
description: 6 figures, abstract accepted by Joint Annual Meeting ISMRM-ESMRMB & ISMRT 31st Annual Meeting
Suppression of Multilayer Graphene Patches during CVD Graphene growth on Copper
Creators: name: Han, Zheng
name: Kimouche, Amina
name: Allain, Adrien
name: Arjmandi-Tash, Hadi
name: Reserbat-Plantey, Antoine
name: Pairis, Sébastien
name: Reita, Valérie
name: Bendiab, Nedjma
name: Coraux, Johann
name: Bouchiat, Vincent
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: By limiting the carbon segregation at the copper surface defects, a pulsed chemical vapor deposition method for single layer graphene growth is shown to inhibit the formation of few-layer regions, leading to a fully single-layered graphene homogeneous at the centimeter scale. Graphene field-effect devices obtained after transfer of pulsed grown graphene on oxidized silicon exhibit mobilities above 5000 cm^2.V^-1.s^-1.
description: 4 pages, 3 figures
Deep electric field predictions by drift-reduced Braginskii theory with plasma-neutral interactions based upon experimental images of boundary turbulence
Creators: name: Mathews, Abhilash
name: Hughes, Jerry
name: Terry, James
name: Baek, Seung-Gyou
Publisher: name: arXiv
Year: 2022
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: We present 2-dimensional turbulent electric field calculations via physics-informed deep learning consistent with (i) drift-reduced Braginskii theory under the framework of an axisymmetric fusion plasma with purely toroidal field and (ii) experimental estimates of the fluctuating electron density and temperature on open field lines obtained from analysis of gas puff imaging of a discharge on the Alcator C-Mod tokamak. The inclusion of effects from the locally puffed atomic helium on particle and energy sources within the reduced plasma turbulence model are found to strengthen correlations between the electric field and electron pressure. The neutrals are also directly associated with broadening the distribution of turbulent field amplitudes and increasing ${\bf E \times B}$ shearing rates. This demonstrates a novel approach in plasma experiments by solving for nonlinear dynamics consistent with partial differential equations and data without encoding explicit boundary nor initial conditions.
description: 6 pages, 3 figures, 2 tables
Computer Simulation in the Controversy over Limits of Growth
Creators: name: Imhof, Peter
Publisher: name: TUHH Universitätsbibliothek
Year: 2000
Subjects: subject: computer simulation
classificationCode: 004
subject: Informatik
classificationCode: 54.76
subject: Computersimulation
subject: Wissenschaft / Methode

description: In the early 70’s, scientists debated hotly the provoking claims that Meadows and his co-authors put forward in their book ‘Limits to Growth’ and which they based on computer simulation runs. This lively debate is reconsidered to flesh out two more general aspects of scientific computer simulation. The first point deals with the question where simulation scientists locate the agency in the activity of computer simulation: Is it the assumptions made by humans or is it the calculations done by the machine that are to be held responsible for the simulation results? The second aspect hints to the problem of how much data are necessary to make a computer simulation a true and meaningful representation of reality. In the case of the debate over Limits to Growth these two questions were answered differently by the proponents and the critics of the simulation study. Whereas many scientific controversies involve scientists who have done research which has lead them to diverging conclusions about the same matter, the debate over Limits to Growth differed in this respect. It can be construed more adequately as the repulsion of researchers who tried to intrude social scientific expertise with the help of computer simulation. This is why computer simulation became one of the key issues in this scientific debate.
Acute Kidney Injury in Children: A 3-Year Retrospective Analysis at Komfo Anokye Teaching Hospital, Ghana
Creators: name: Sampson Antwi
name: Anima Sarfo
name: Amoah, Abigail
name: Appia, Anna Serwaa
name: Obeng, Esther
Publisher: name: Zenodo
Year: 2021
Subjects: Acute kidney injury
aetiology
resource constraint regions
outcomes

description: Background/Aims: Acute kidney injury (AKI) is a relatively common condition encountered in everyday paediatric practice. It remains a significant contributor to preventable deaths especially in resource constraint regions of the world largely due to lack of dialysis services. AKI remains a significant contributor to the mortality of critically ill children. Mortality outcomes depend on such factors as aetiology, medical setting, co-morbidities, and availability of dialysis therapy. This 3-year data analysis (2010-2012) was undertaken to determine the aetiology and treatment/mortality outcomes of children with AKI presenting to a Teaching Hospital in Ghana. AKI was defined in this analysis by the RIFLE and KDIGO criteria. Results: Two hundred and six (206) cases of AKI were recorded over the period out of a total of 664 renal cases. Haemoglobinuria, obstructive uropathy and tumour infiltration of the kidneys were the leading causes of AKI (37.8%). 9.2% of cases were diarrhoeal-related with glomerulonephritides occurring in 12.1% of cases. Seventy-one (34.5%) of the 206 AKI cases required dialysis which could only be provided for 25 (35.2%), 16 (64%) of whom survived. Forty-three (20.9%) children died, while 144 (69.9%) survived. Thirty-one (72%) of the patients who died needed dialysis. Conclusion: In comparison to previous studies across the world, there is huge burden of AKI among hospitalized children in Kumasi, Ghana. Haemoglobinuria and tumour-related conditions accounted for most cases of AKI more than diarrhoea-associated conditions and postinfectious glomerulonephritis as were previously reported or postulated. Most AKI deaths were related to lack of dialysis service. In view of the less technical requirements compared with other modalities of renal replacement therapy, peritoneal dialysis should be promoted across Africa to curtail needless deaths from AKI.
A survey on hyperbolicity of projective hypersurfaces
Creators: name: Diverio, Simone
name: Rousseau, Erwan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Algebraic Geometry (math.AG)
subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 32Q45, 14J70, 14F10

description: These are lecture notes of a course held at IMPA, Rio de Janiero, in september 2010: the purpose was to present recent results on Kobayashi hyperbolicity in complex geometry. Our ultimate goal is to describe the results obtained on questions related to the geometry of entire curves traced in generic complex projective hypersurfaces of high degree. For the convenience of the reader, this survey tries to be as self contained as possible.
description: 108 pages, 2 figures
On Machine Learning-Driven Surrogates for Sound Transmission Loss Simulations
Creators: name: Cunha, Barbara
name: Zine, Abdel-Malek
name: Ichchou, Mohamed
name: Droz, Christophe
name: Foulard, Stéphane
Publisher: name: arXiv
Year: 2022
Subjects: subject: Sound (cs.SD)
subject: Machine Learning (cs.LG)
subject: Audio and Speech Processing (eess.AS)
subject: Medical Physics (physics.med-ph)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Physical sciences

description: Surrogate models are data-based approximations of computationally expensive simulations that enable efficient exploration of the model's design space and informed decision-making in many physical domains. The usage of surrogate models in the vibroacoustic domain, however, is challenging due to the non-smooth, complex behavior of wave phenomena. This paper investigates four Machine Learning (ML) approaches in the modelling of surrogates of Sound Transmission Loss (STL). Feature importance and feature engineering are used to improve the models' accuracy while increasing their interpretability and physical consistency. The transfer of the proposed techniques to other problems in the vibroacoustic domain and possible limitations of the models are discussed.
Discussion of "Feature Matching in Time Series Modeling" by Y. Xia and H. Tong
Creators: name: Yao, Qiwei
Publisher: name: arXiv
Year: 2012
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Discussion of "Feature Matching in Time Series Modeling" by Y. Xia and H. Tong [arXiv:1104.3073]
description: Published in at http://dx.doi.org/10.1214/11-STS345D the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Search for hidden-charm pentaquark states in three-body final states
Creators: name: Xie, Jia-Ming
name: Ling, Xi-Zhe
name: Liu, Ming-Zhu
name: Geng, Li-Sheng
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The three pentaquark states, $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$, discovered by the LHCb Collaboration in 2019, are widely recognized as $\bar{D}^{(\ast)}Σ_{c}$ hadronic molecules. Together with their four $\bar{D}^{(*)}Σ_{c}^{\ast}$ partners dictated by heavy quark spin symmetry they present a complete multiplet of hadronic molecules of $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$. It is widely recognized that to understand their nature, other discovery channels play an important role. In this work, we investigate two three-body decay modes of the $\bar{D}^{(\ast)}Σ_{c}^{(\ast)}$ molecules. The tree-level modes proceed via off-shell $Σ_{c}^{(\ast)}$ baryons, $\bar{D}^{(\ast)}Σ_{c}^{(\ast)} \to \bar{D}^{(\ast)}\left(Σ_{c}^{(\ast)}\to Λ_{c}π\right)\to\bar{D}^{(\ast)}Λ_{c}π$, while the triangle-loop modes proceed through $\bar{D}^{\ast}Σ_{c}^{(\ast)}\to J/ψNπ$, $η_{c}Nπ$ via $\bar{D}Σ_{c}^{(\ast)}$ rescattering to $J/ψN$ and $η_{c}N$. Our results indicate that the decay widths of the $P_{c}(4457)$ and $\bar{D}^{(\ast)}Σ_{c}^{\ast}$ states into $\bar{D}^{(\ast)}Λ_{c}π$ are several MeV, as a result can be observed in the upcoming Run 3 and Run 4 of LHC. The partial decay widths into $\bar{D}^{(\ast)}Λ_{c}π$ of the $P_{c}(4312)$ and $P_{c}(4440)$ states range from tens to hundreds of keV. In addition, the partial decay widths of $\bar{D}^{\ast}Σ_{c}$ molecules into $J/ψN π$ and $η_c N π$ are several keV and tens of keV, respectively, and the partial decay widths of $\bar{D}^{\ast}Σ_{c}^{\ast}$ molecules into $J/ψN π$ vary from several keV to tens of keV. These three-body decay modes of the pentaquark states are of great value to further observations of the pentaquark states and to a better understanding of their nature.
description: version accpeted for publication in EPJC
Heat transport of the quasi-one-dimensional alternating spin chain material (CH_{3})_{2}NH_{2}CuCl_{3}
Creators: name: Chen, L. M.
name: Wang, X. M.
name: Ke, W. P.
name: Zhao, Z. Y.
name: Liu, X. G.
name: Fan, C.
name: Li, Q. J.
name: Zhao, X.
name: Sun, X. F.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report a study of the low-temperature heat transport in the quasi-one-dimensional S = 1/2 alternating antiferromagnetic-ferromagnetic chain compound (CH_{3})_{2}NH_{2}CuCl_{3}. Both the temperature and magnetic-field dependencies of thermal conductivity are very complicated, pointing to the important role of spin excitations. It is found that magnetic excitations act mainly as the phonon scatterers in a broad temperature region from 0.3 to 30 K. In magnetic fields, the thermal conductivity show drastic changes, particularly at the field-induced transitions from the low-field Néel state to the spin-gapped state, the field-induced magnetic ordered state, and the spin polarized state. In high fields, the phonon conductivity is significantly enhanced because of the weakening of spin fluctuations.
description: 6 pages, 4 figures, accepted for publication in Phys. Rev. B
A direct measurement of the distance to the Galactic center using the kinematics of bar stars
Creators: name: Leung, Henry W.
name: Bovy, Jo
name: Mackereth, J. Ted
name: Hunt, Jason A. S.
name: Lane, Richard R.
name: Wilson, John C.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The distance to the Galactic center $R_0$ is a fundamental parameter for understanding the Milky Way, because all observations of our Galaxy are made from our heliocentric reference point. The uncertainty in $R_0$ limits our knowledge of many aspects of the Milky Way, including its total mass and the relative mass of its major components, and any orbital parameters of stars employed in chemo-dynamical analyses. While measurements of $R_0$ have been improving over a century, measurements in the past few years from a variety of methods still find a wide range of $R_0$ being somewhere within $8.0$ to $8.5\,\mathrm{kpc}$. The most precise measurements to date have to assume that Sgr A$^*$ is at rest at the Galactic center, which may not be the case. In this paper, we use maps of the kinematics of stars in the Galactic bar derived from APOGEE DR17 and Gaia EDR3 data augmented with spectro-photometric distances from the \texttt{astroNN} neural-network method. These maps clearly display the minimum in the rotational velocity $v_T$ and the quadrupolar signature in radial velocity $v_R$ expected for stars orbiting in a bar. From the minimum in $v_T$, we measure $R_0 = 8.23 \pm 0.12\,\mathrm{kpc}$. We validate our measurement using realistic $N$-body simulations of the Milky Way. We further measure the pattern speed of the bar to be $Ω_\mathrm{bar} = 40.08\pm1.78\,\mathrm{km\,s}^{-1}\mathrm{kpc}^{-1}$. Because the bar forms out of the disk, its center is manifestly the barycenter of the bar+disc system and our measurement is therefore the most robust and accurate measurement of $R_0$ to date.
Microstructure of Charged AdS Black Hole with Minimal Length Effects
Creators: name: Bai, Ningchen
name: He, Aoyun
name: Tao, Jun
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this work, the microstructure of charged AdS black holes under minimal length effects is investigated. We study the thermodynamics of black holes in the extended phase space, where the cosmological constant is regarded as the thermodynamic pressure. The modified Hawking temperature and phase transition are obtained based on the generalized uncertainty principle (GUP). Then, using thermodynamic geometry, we show that the microstructure of black holes can be determined by the ratio of GUP parameter to charge. For a small ratio, the black hole exhibits the typical RN-AdS microstructure with van der Waals phase transition and repulsive/attractive interactions. As the ratio increases, the reentrant phase transition takes place, and both the repulsion-attraction coexisted black hole and the attraction dominated black hole can be found in this case. For a large ratio, the black hole behaves like a Schwarzchild-AdS black hole in which neither phase transition nor repulsive interaction exists. These results suggest that the GUP effect will reduce the repulsive interaction presented by the charged AdS black hole, which can also be qualitatively understood from the perspective of black hole molecules.
description: 29 pages, 10 figures
Prediction of Catastrophes: an experimental model
Creators: name: Peters, Randall D.
name: Berre, Martine Le
name: Pomeau, Yves
Publisher: name: arXiv
Year: 2012
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: Catastrophes of all kinds can be roughly defined as short duration-large amplitude events following and followed by long periods of "ripening". Major earthquakes surely belong to the class of 'catastrophic' events. Because of the space-time scales involved, an experimental approach is often difficult, not to say impossible, however desirable it could be. Described in this article is a "laboratory" setup that yields data of a type that is amenable to theoretical methods of prediction. Observations are made of a critical slowing down in the noisy signal of a solder wire creeping under constant stress. This effect is shown to be a fair signal of the forthcoming catastrophe in both of two dynamical models. The first is an "abstract" model in which a time dependent quantity drifts slowly but makes quick jumps from time to time. The second is a realistic physical model for the collective motion of dislocations (the Ananthakrishna set of equations for creep). Hope thus exists that similar changes in the response to noise could forewarn catastrophes in other situations, where such precursor effects should manifest early enough.
Dark $SU(2)_D$ Gauge Symmetry and Scotogenic Dirac Neutrinos
Creators: name: Borah, Debasish
name: Ma, Ernest
name: Nanda, Dibyendu
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Dark matter is postulated to transform under the non-Abelian $SU(2)_D$ gauge symmetry. Its connection to Dirac neutrino masses is explored.
description: 16 pages, 10 figures
Existenz, Eindeutigkeit und Regularität stationärer Wellenströmungen, die von Druckverteilungen an der Wasseroberfläche verursacht werden
Creators: name: Gamst, Andreas
Publisher: name: TUHH Universitätsbibliothek
Year: 1979
Subjects: classificationCode: 52.00
subject: Maschinenbau, Energietechnik, Fertigungstechnik: Allgemeines

description: Existenz, Eindeutigkeit und Regularität stationärer Wellenströmungen, die von Druckverteilungen an der Wasseroberfläche verursacht werden -Lineare Theorie-
Characterizing X-ray binary long-term variability
Creators: name: Kotze, M. M.
name: Charles, P. A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Long-term ("superorbital") periods or modulations have been detected in a wide variety of both low and high-mass X-ray binaries at X-ray and optical wavelengths. A variety of mechanisms have been proposed to account for the variability properties, such as precessing and/or warped accretion discs, amongst others. The All Sky Monitor on board the Rossi X-ray Timing Explorer provides the most extensive (~15 years) and sensitive X-ray archive for studying such behaviour. It is also clear that such variations can be intermittent and/or a function of X-ray spectral state. Consequently, we use a time-dependent Dynamic Power Spectrum method to examine how these modulations vary with time in 25 X-ray binaries for which superorbital periodicities have been previously reported. Our aim is to characterize these periodicities in a completely systematic way. Some (such as Her X-1 and LMC X-4) are remarkably stable, but others show a range of properties, from even longer variability time-scales to quite chaotic behaviour.
description: 17 pages, 26 figures, 4 tables, Accepted for publication in MNRAS on 4 November 2011
Peter M. Maitlis - publications from PETER M. MAITLIS. 15 January 1933—18 May 2022
Creators: name: Crabtree, Robert H.
Publisher: name: The Royal Society
Year: 2023
Subjects: subject: Organic Chemistry
subject: FOS: Chemical sciences

description: Starting life with a dramatic escape from Nazi Germany, Peter Maitlis rose to make important contributions to a variety of areas of organometallic chemistry, many of which have had a continuing influence in both academic and industrial practice. Perhaps his most significant work was his early discovery of pentamethylcyclopentadienyl complexes of rhodium and iridium, compounds that have been eagerly taken up elsewhere for a very wide variety of purposes. His mechanistic work related to the Fischer–Tropsch and Cativa processes had important industrial implications.