cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
A STUDY OF V79 CELL SURVIVAL AFTER PROTON AND CARBON ION BEAMS AS REPRESENTED BY THE PARAMETERS OF KATZ' TRACK STRUCTURE MODEL
Creators: name: Leszek, Grzanka
name: Waligórski, Michael P.R.
name: Bassler, Niels
Publisher: name: Zenodo
Year: 2014

description: Katz’s theory of cellular track structure (1) is an amorphous analytical model which applies a set of four cellular parameters representing survival of a given cell line after ion irradiation. Usually the values of these parameters are best fitted to a full set of experimentally measured survival curves available for a variety of ions. Once fitted, using these parameter values and the analytical formulae of the model calculations, cellular survival curves and RBE may be predicted for that cell line after irradiation by any ion, including mixed ion fields. While it is known that the Katz model parameters fitted to heavier ion data may yield unsatisfactory predictions of proton response, to our knowledge, no comprehensive data set which includes proton and heavier ion irradiations, measured in one laboratory, has been published. To study the consistency of evaluating parameters of this model from different sets of data obtained for the same cell line and different ions, measured at different laboratories, we have fitted model parameters to a set of carbon-irradiated V79 cells, published by Furusawa et al. (2), and to a set of proton-irradiated V79 cells, published by Wouters et al. (3), separately. We found that values of model parameters best fitted to the carbon data of Furusawa et al. yielded predictions of V79 survival after proton irradiation which did not match the V79 proton data of Wouters et al. Fitting parameters to both sets combined did not improve the accuracy of model predictions of the proton response. This suggests that for increased accuracy of a therapy planning system based on Katz’s model, different sets of parameters may need to be used to represent cell survival after proton irradiation from those representing survival of this cell line after heavier ions, up to and including carbon irradiation. 1. Katz, R., Track structure in radiobiology and in radiation detection. Nuclear Track Detection 2: 1-28 (1978). 2. Furusawa Y. et al. Inactivation of aerobic and hypoxic cells from three different cell lines by accelerated 3He-, 12C- and 20Ne beams. Radiat Res. 2012 Jan; 177(1):129-31. 3. Wouters BG et al. Measurements of relative biological effectiveness of the 70 MeV proton beam at TRIUMF using Chinese hamster V79 cells and the high precision cell sorter assay. Radiat Res.1996 Aug. 146(2): 159-170.
Towards an Efficient Combination of Adaptive Routing and Queuing Schemes in Fat-Tree Topologies
Creators: name: Rocher-Gonzalez, Jose
name: Escudero-Sahuquillo, Jesus
name: Garcia, Pedro J.
name: Quiles, Francisco J.
name: Mora, Gaspar
Publisher: name: arXiv
Year: 2025
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: The interconnection network is a key element in High-Performance Computing (HPC) and Datacenter (DC) systems whose performance depends on several design parameters, such as the topology, the switch architecture, and the routing algorithm. Among the most common topologies in HPC systems, the Fat-Tree offers several shortest-path routes between any pair of end-nodes, which allows multi-path routing schemes to balance traffic flows among the available links, thus reducing congestion probability. However, traffic balance cannot solve by itself some congestion situations that may still degrade network performance. Another approach to reduce congestion is queue-based flow separation, but our previous work shows that multi-path routing may spread congested flows across several queues, thus being counterproductive. In this paper, we propose a set of restrictions to improve alternative routes selection for multi-path routing algorithms in Fat-Tree networks, so that they can be positively combined with queuing schemes.
description: 53 pages
Can plume-induced internal gravity waves regulate the core rotation of subgiant stars?
Creators: name: Pinçon, C.
name: Belkacem, K.
name: Goupil, M. J.
name: Marques, J. P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The seismic data provided by the satellites CoRoT and Kepler enabled us to probe the internal rotation of thousands of evolved low-mass stars. Subsequently, several studies showed that current stellar evolution codes are unable to reproduce the low core rotation rates observed in these stars. These results indicate that an additional angular momentum transport process is necessary to counteract the spin up due to the core contraction during the post-main sequence evolution. For several candidates, the transport induced by internal gravity waves (IGW) could play a non-negligible role. In this work, we investigate the effect of IGW generated by penetrative convection on the internal rotation of low-mass stars from the subgiant branch to the beginning of the red giant branch. We show that IGW can efficiently counteract the contraction-driven spin up of the core of subgiant stars if the amplitude of the radial-differential rotation (between the center of the star and the top of the radiative zone) is higher than a threshold value. This threshold depends on the evolutionary stage and is comparable to the differential rotation rates inferred for a sample of subgiant stars observed by the satellite Kepler. Such an agreement can therefore be interpreted as the consequence of a regulation mechanism driven by IGW. This result is obtained under the assumption of a smooth rotation profile and holds true even if a wide range of values is considered for the parameters of the generation model. In contrast, on the red giant branch, we find that IGW remain insufficient, on their own, to explain the observations. We conclude that plume-induced IGW are able to efficiently extract angular momentum from the core of subgiant stars and accordingly have to be taken into account. On the red giant branch, another transport mechanism must likely be invoked.
description: Accepted for publication in A&A, 22 pages
Grand canonical electronic density-functional theory: algorithms and applications to electrochemistry
Creators: name: Sundararaman, Ravishankar
name: Goddard, William A.
name: Arias, Tomas A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: First-principles calculations combining density-functional theory and continuum solvation models enable realistic theoretical modeling and design of electrochemical systems. When a reaction proceeds in such systems, the number of electrons in the portion of the system treated quantum mechanically changes continuously, with a balancing charge appearing in the continuum electrolyte. A grand-canonical ensemble of electrons at a chemical potential set by the electrode potential is therefore the ideal description of such systems that directly mimics the experimental condition. We present two distinct algorithms, a self-consistent field method (GC-SCF) and a direct variational free energy minimization method using auxiliary Hamiltonians (GC-AuxH), to solve the Kohn-Sham equations of electronic density-functional theory directly in the grand canonical ensemble at fixed potential. Both methods substantially improve performance compared to a sequence of conventional fixed-number calculations targeting the desired potential, with the GC-AuxH method additionally exhibiting reliable and smooth exponential convergence of the grand free energy. Finally, we apply grand-canonical DFT to the under-potential deposition of copper on platinum from chloride-containing electrolytes and show that chloride desorption, not partial copper monolayer formation, is responsible for the second voltammetric peak.
description: 15 pages, 12 figures
Magnetospheric Truncation, Tidal Inspiral, and the Creation of Short and Ultra-Short Period Planets
Creators: name: Lee, Eve J.
name: Chiang, Eugene
Publisher: name: arXiv
Year: 2017
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Sub-Neptunes around FGKM dwarfs are evenly distributed in log orbital period down to $\sim$10 days, but dwindle in number at shorter periods. Both the break at $\sim$10 days and the slope of the occurrence rate down to $\sim$1 day can be attributed to the truncation of protoplanetary disks by their host star magnetospheres at co-rotation. We demonstrate this by deriving planet occurrence rate profiles from empirical distributions of pre-main-sequence stellar rotation periods. Observed profiles are better reproduced when planets are distributed randomly in disks---as might be expected if planets formed in situ---rather than piled up near disk edges, as would be the case if they migrated in by disk torques. Planets can be brought from disk edges to ultra-short ($< 1$ day) periods by asynchronous equilibrium tides raised on their stars. Tidal migration can account for how ultra-short period planets (USPs) are more widely spaced than their longer period counterparts. Our picture provides a starting point for understanding why metal-rich stars tend to harbor more USPs, and why the sub-Neptune population drops at $\sim$10 days regardless of whether the host star is of type FGK or early M. We predict planet occurrence rates around A stars to also break at short periods, but at $\sim$1 day instead of $\sim$10 days because A stars rotate faster than lower mass stars (this prediction presumes that the planetesimal building blocks of planets can drift inside the dust sublimation radius).
description: ApJ in press
Hybrid Kinematic Control for Rigid Body Pose Stabilization using Dual Quaternions
Creators: name: Kussaba, Hugo T. M.
name: Figueredo, Luis F. C.
name: Ishihara, João Y.
name: Adorno, Bruno V.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Optimization and Control (math.OC)
subject: Systems and Control (eess.SY)
subject: FOS: Mathematics
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: In this paper, we address the rigid body pose stabilization problem using dual quaternion formalism. We propose a hybrid control strategy to design a switching control law with hysteresis in such a way that the global asymptotic stability of the closed-loop system is guaranteed and such that the global attractivity of the stabilization pose does not exhibit chattering, a problem that is present in all discontinuous-based feedback controllers. Using numerical simulations, we illustrate the problems that arise from existing results in the literature -- as unwinding and chattering -- and verify the effectiveness of the proposed controller to solve the robust global pose stability problem.
description: 36 pages, 9 figures, accepted by Journal of the Franklin Institute
title: Molecular structures and protonation state of 2-Mercaptopyridine in aqueous solution
Creators: name: Eckert, Sebastian
name: Miedema, Piter
name: Quevedo, Wilson
name: O'Cinneide, B.
name: Fondell, Mattis
name: Beye, Martin
name: Pietzsch, Annette
name: Ross, Matthew R.
name: Khalil, Munira
name: Föhlisch, Alexander
Publisher: name: Universität Potsdam
Year: 2020

description: The speciation of 2-Mercaptopyridine in aqueous solution has been investigated with nitrogen 1s Near Edge X-ray Absorption Fine Structure spectroscopy and time dependent Density Functional Theory. The prevalence of distinct species as a function of the solvent basicity is established. No indications of dimerization towards high concentrations are found. The determination of different molecular structures of 2-Mercaptopyridine in aqueous solution is put into the context of proton-transfer in keto-enol and thione-thiol tautomerisms. (C) 2016 The Authors. Published by Elsevier B.V.
description: Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, 953
Excitonic coupling dominates the homogeneous photoluminescence excitation linewidth in semicrystalline polymeric semiconductors
Creators: name: Grégoire, Pascal
name: Vella, Eleonora
name: Dyson, Matthew
name: Bazán, Claudia M.
name: Leonelli, Richard
name: Stingelin, Natalie
name: Stavrinou, Paul N.
name: Bittner, Eric R.
name: Silva, Carlos
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: We measure the homogeneous excitation linewidth of regioregular poly(3-hexylthiophene), a model semicrystalline polymeric semiconductor, by means of two-dimensional coherent photoluminescence excitation spectroscopy. At a temperature of 8\,K, we find a linewidth that is always $\gtrsim 110$\,meV full-width-at-half-maximum, which is a significant fraction of the total linewidth. It displays a spectral dependence and is minimum near the 0--0 origin peak. We interpret this spectral dependence of the homogeneous excitation linewidth within the context of a weakly coupled aggregate model.
description: 13 pages, 4 figures, Supplementary Material
düşük hapı 0543 529 72 06 Medical bacteriology.
Creators: name: düşük hapı türkiye bayii satış noktası, 0543 529 72 06
Publisher: name: figshare
Year: 2024
Subjects: classificationCode: 320701
subject: Medical bacteriology

description: düşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı. 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriologydüşük hapı 0543 529 72 06 Medical bacteriology
title: The genetics of an early Neolithic pastoralist from the Zagros, Iran
Creators: name: Gallego-Llorente, Marcos
name: Sarah, Connell
name: Jones, Eppie R.
name: Merrett, Deborah C.
name: Jeon, Y.
name: Eriksson, Anders
name: Siska, Veronika
name: Gamba, Cristina
name: Meiklejohn, Christopher
name: Beyer, Robert
name: Jeon, Sungwon
name: Cho, Yun Sung
name: Hofreiter, Michael
name: Bhak, Jong
name: Manica, Andrea
name: Pinhasi, Ron
Publisher: name: Universität Potsdam
Year: 2020

description: The agricultural transition profoundly changed human societies. We sequenced and analysed the first genome (1.39x) of an early Neolithic woman from Ganj Dareh, in the Zagros Mountains of Iran, a site with early evidence for an economy based on goat herding, ca. 10,000 BP. We show that Western Iran was inhabited by a population genetically most similar to hunter-gatherers from the Caucasus, but distinct from the Neolithic Anatolian people who later brought food production into Europe. The inhabitants of Ganj Dareh made little direct genetic contribution to modern European populations, suggesting those of the Central Zagros were somewhat isolated from other populations of the Fertile Crescent. Runs of homozygosity are of a similar length to those from Neolithic farmers, and shorter than those of Caucasus and Western Hunter-Gatherers, suggesting that the inhabitants of Ganj Dareh did not undergo the large population bottleneck suffered by their northern neighbours. While some degree of cultural diffusion between Anatolia, Western Iran and other neighbouring regions is possible, the genetic dissimilarity between early Anatolian farmers and the inhabitants of Ganj Dareh supports a model in which Neolithic societies in these areas were distinct.
description: Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, 952
A STUDY ON SEIQR MATHEMATICAL MODEL WITH VACCINATION AND PREVENTIVE CONTROL EFFORTS
Creators: name: Sangotola, Adekunle
Publisher: name: figshare
Year: 2022
Subjects: Ordinary differential equations, difference equations and dynamical systems

description: We present the dynamics of a SEIQR mathematical model with vaccination and preventive control measure in the susceptible class. The basic reproduction number of the model dynamics is obtained by using the next generation matrix method. The disease free equilibrium point of the model is found to be locally asymptotically stable if $R_0\mid_{\omega=0}<1$ and a unique endemic equilibrium point exist if $R_0\mid_{\omega=0}>1$. The disease free equilibrium point of the model is found to be globally asymptotically stable if $R_0\mid_{\omega=0}\leq1$ by using a suitable Lyapunov function. The contribution of the model parameters on the basic reproduction number is also determined through sensitivity analysis.
Localization in open quantum systems
Creators: name: Yusipov, I.
name: Laptyeva, T.
name: Denisov, S.
name: Ivanchenko, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In an isolated single-particle quantum system a spatial disorder can induce Anderson localization. Being a result of interference, this phenomenon is expected to be fragile in the face of dissipation. Here we show that dissipation can drive a disordered system into a steady state with tunable localization properties. This can be achieved with a set of identical dissipative operators, each one acting non-trivially only on a pair of neighboring sites. Operators are parametrized by a uniform phase, which controls selection of Anderson modes contributing to the state. On the microscopic level, quantum trajectories of a system in a localized steady regime exhibit intermittent dynamics consisting of long-time sticking events near selected modes interrupted by jumps between them.
description: 5 pages, 5 figures
The influence of localization transition on dynamical properties for an extended Aubry-André-Harper model
Creators: name: Zhao, X. L.
name: Shi, Z. C.
name: Yu, C. S.
name: Yi, X. X.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We show the localization transition and its effect on two dynamical processes for an extended Aubry-André-Harper model with incommensurate on-site and hopping potentials. After specifying an extended Aubry-André-Harper model, we check the localization transition for all the eigenstates and eigenenergy band splitting behavior versus a system parameter. To examine the effect of localization transition on dynamical processes, firstly, the slowly pumping of the edge states are examined. In the dynamical processes, the system acts as conductor for the excitation in the nonlocal region and insulator in the localized region. Then by quantum Lyapunov control method with different control Hamiltonians, we prepare an edge localized state which exists in the nonlocal region. Compared to that in the nonlocal region, the control effect is suppressed in the localized region. Then we employ the entropy and occupation imbalance between even and odd sites to indicate the localization transition further. Finally, the experimental schemes based on cold atoms trapped quasiperiodic optical lattice and coupled optical waveguide arrays are suggested.
Multiple solutions of nonlinear equations involving the square root of the Laplacian
Creators: name: Bisci, Giovanni Molica
name: Repovš, Dušan D.
name: Vilasi, Luca
Publisher: name: arXiv
Year: 2017
Subjects: subject: Analysis of PDEs (math.AP)
subject: Operator Algebras (math.OA)
subject: Optimization and Control (math.OC)
subject: FOS: Mathematics
subject: 35A15, 35S15, 45G05, 47G20, 49J35,

description: In this paper we examine the existence of multiple solutions of parametric fractional equations involving the square root of the Laplacian $A_{1/2}$ in a smooth bounded domain $Ω\subset \mathbb{R}^n$ ($n\geq 2$) and with Dirichlet zero-boundary conditions, i.e. \begin{equation*} \left\{ \begin{array}{ll} A_{1/2}u=λf(u) & \mbox{ in } Ω\\ u=0 & \mbox{ on } \partialΩ. \end{array}\right. \end{equation*} The existence of at least three $L^{\infty}$-bounded weak solutions is established for certain values of the parameter $λ$ requiring that the nonlinear term $f$ is continuous and with a suitable growth. Our approach is based on variational arguments and a variant of Caffarelli-Silvestre's extension method.
Die Oberfläche des allgemeinen Ellipsoiden
Creators: name: Schröer, Harald
Publisher: name: Zenodo
Year: 2015
Subjects: surface, area, general ,ellipsoid,semi-axis

description: Eine Formel für die Oberfläche eines allgmeinen Ellipsoiden, bei der man den Einfluß der verschiedenen Größen gut sehen kann, wird vorgestellt. Anschließend werden Beispiele berechnet.

description: German
0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics).
Creators: name: düşük hapı türkiye bayii satış noktası, 0543 529 72 06
Publisher: name: figshare
Year: 2024
Subjects: classificationCode: 320506
subject: Medical biochemistry - proteins and peptides (incl. medical proteomics)

description: düşük hapı 0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)0543 529 72 06 Medical biochemistry - proteins and peptides (incl. medical proteomics)
Swimmer-microrheology
Creators: name: Yasuda, Kento
name: Okamoto, Ryuichi
name: Komura, Shigeyuki
Publisher: name: arXiv
Year: 2017
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We discuss a locomotion of a three-sphere microswimmer in a viscoelastic medium and propose a new type of active microrheology. We derive a relation which connects average swimming velocity and frequency-dependent viscosity of the surrounding medium. In this relation, the viscous contribution can exist only when the time-reversal symmetry is broken, whereas the elastic contribution is present only when the structural symmetry of the swimmer is broken. The Purcell's scallop theorem breaks down for a three-sphere swimmer in a viscoelastic medium.
X-ray flux variability of active galactic nuclei observed using NuSTAR
Creators: name: Rani, Priyanka
name: Stalin, C. S.
name: Rakshit, Suvendu
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We present results on a systematic study of flux variability on hourly time-scales in a large sample of active galactic nuclei (AGN) in the 3-79 keV band using data from Nuclear Spectroscopic Telescope Array. Our sample consists of 4 BL Lac objects (BL Lacs), 3 flat spectrum radio quasars (FSRQs) 24 Seyfert 1, 42 Seyfert 2 and 8 narrow line Seyfert 1 (NLSy1) galaxies. We find that in the 3-79 keV band, about 65% of the sources in our sample show significant variations on hourly time scales. Using Mann-Whitney U-test and Kolmogorov-Smirnov test, we find no difference in the variability behaviour between Seyfert 1 and 2 galaxies. The blazar sources (FSRQs and BL Lacs) in our sample, are more variable than Seyfert galaxies that include Seyfert 1 and Seyfert 2 in the soft (3-10 keV), hard (10-79 keV) and total (3-79 keV) bands. NLSy1 galaxies show the highest duty cycle of variability (87%), followed by BL Lacs (82%), Seyfert galaxies (56%) and FSRQs (23%). We obtained flux doubling/halving time in the hard X-ray band less than 10 min in 11 sources. The flux variations between the hard and soft bands in all the sources in our sample are consistent with zero lag.
description: 15 pages, 7 figures, 10 tables, accepted for publication in MNRAS
Stability of a horizontal viscous fluid layer in a vertical time periodic electric field
Creators: name: Bandopadhyay, Aditya
name: Hardt, Steffen
Publisher: name: arXiv
Year: 2017
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The stability of a horizontal interface between two viscous fluids, one of which is conducting and the other is dielectric, acted upon by a vertical time-periodic electric field is considered. The two fluids are bounded by electrodes separated by a finite distance. By means of Floquet theory, the marginal stability curves are obtained, thereby elucidating the dependency of the critical voltage and wavenumber upon the fluid viscosities. The limit of vanishing viscosities is shown to be in excellent agreement with the marginal stability curves predicted by means of a Mathieu equation. The methodology to obtain the marginal stability curves developed here is applicable to any arbitrary but time periodic-signal, as demonstrated for the case of a signal with two different frequencies. As a special case, the marginal stability curves for an applied ac voltage biased by a dc voltage are depicted. It is shown that the mode coupling caused by the normal stress at the interface due to the electric field leads to appearance of harmonic modes and subharmonic modes. This is in contrast to the application of a voltage with a single frequency which always leads to a harmonic mode. Whether a harmonic or subharmonic mode is the most unstable one depends on details of the excitation signal. It is also shown that the electrode spacing has a distinct effect on the stability bahavior of the system.
Multiscale modelling of the morphology and spatial distribution of θ' precipitates in Al-Cu alloys
Creators: name: Liu, H.
name: Bellón, B.
name: LLorca, J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A multiscale approach based on the phase-field model is developed to simulate homogeneous and heterogeneous formation of θ' precipitates during high temperature ageing in Al-Cu alloys. The model parameters that determine the different energy contributions (chemical free energy, interfacial energy, lattice parameters, elastic constants) were obtained from either computational thermodynamics databases or from first-principles density functional theory and molecular statics simulations. From the information, the evolution and equilibrium morphology of the θ' precipitates is simulated in 3D using the phase-field model. The model was able to reproduce the evolution of the different orientation variants of plate-like shaped θ' precipitates with orientation relationship (001)θ'//(001)α and [100]θ'//[100]α during homogeneous nucleation as well as the heterogeneous nucleation on dislocations, leading to the formation of precipitate arrays. Heterogeneous nucleation on pre-existing dislocation(s) was triggered by the interaction energy between the dislocation stress field and the stress-free transformation strain associated to the nucleation of the θ' precipitates. Moreover, the mechanisms controlling the evolution of the morphology and the equilibrium aspect ratio of the precipitates were ascertained. All the predictions of the multiscale model were in good agreement with experimental data.
Simultaneous detection of quantum oscillations from bulk and topological surface states in metallic Bi2Se2.1Te0.9
Creators: name: Shrestha, Keshav
name: Graf, David E.
name: Marinova, Vera
name: Lorenz, Bernd
name: Chu, Paul C. W.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Shubnikov-de Haas (SdH) oscillations in metallic Bi2Se2.1Te0.9 are studied in magnetic fields up to 35 Tesla. It is demonstrated that two characteristic frequencies determine the quantum oscillations of the conductivity. Angle dependent measurements and calculations of the Berry phase show that the two frequencies F1 and F2 describe oscillations from surface and bulk carriers, respectively. At low magnetic fields, only SdH oscillation from topological surface states can be detected whereas at high magnetic field the bulk oscillations dominate. The origin of the separation of bulk and surface SdH oscillations into different magnetic field ranges is revealed in the difference of the cyclotron masses mc. The bulk mc is nearly three times larger than the surface cyclotron mass resulting in a stronger attenuation of the bulk oscillation amplitude upon decreasing magnetic field. This makes it possible to detect and characterize the surface SdH oscillations in the low-field range and the bulk oscillations at high magnetic fields.
description: Accepted for publication in Philosophical Magazine
Neuromorphic Deep Learning Machines
Creators: name: Neftci, Emre
name: Augustine, Charles
name: Paul, Somnath
name: Detorakis, Georgios
Publisher: name: arXiv
Year: 2016
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: An ongoing challenge in neuromorphic computing is to devise general and computationally efficient models of inference and learning which are compatible with the spatial and temporal constraints of the brain. One increasingly popular and successful approach is to take inspiration from inference and learning algorithms used in deep neural networks. However, the workhorse of deep learning, the gradient descent Back Propagation (BP) rule, often relies on the immediate availability of network-wide information stored with high-precision memory, and precise operations that are difficult to realize in neuromorphic hardware. Remarkably, recent work showed that exact backpropagated weights are not essential for learning deep representations. Random BP replaces feedback weights with random ones and encourages the network to adjust its feed-forward weights to learn pseudo-inverses of the (random) feedback weights. Building on these results, we demonstrate an event-driven random BP (eRBP) rule that uses an error-modulated synaptic plasticity for learning deep representations in neuromorphic computing hardware. The rule requires only one addition and two comparisons for each synaptic weight using a two-compartment leaky Integrate & Fire (I&F) neuron, making it very suitable for implementation in digital or mixed-signal neuromorphic hardware. Our results show that using eRBP, deep representations are rapidly learned, achieving nearly identical classification accuracies compared to artificial neural network simulations on GPUs, while being robust to neural and synaptic state quantizations during learning.
Magneto-Optical Detection of the Spin Hall Effect in Pt and W Thin Films
Creators: name: Stamm, Christian
name: Murer, Christoph
name: Berritta, Marco
name: Feng, Junxiao
name: Gabureac, Mihai
name: Oppeneer, Peter M.
name: Gambardella, Pietro
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Here we report the measurement of the interfacial spin accumulation induced by the spin Hall effect in Pt and W thin films using magneto-optical Kerr microscopy. We show that the Kerr rotation has opposite sign in Pt and W and scales linearly with current density. By comparing the experimental results with ab-initio calculations of the spin Hall and magneto-optical Kerr effects, we quantitatively determine the current-induced spin accumulation at the Pt interface as $5*10^{-12} μ_B$A$^{-1}$cm$^2$ per atom. From thickness-dependent measurements, we determine the spin diffusion length in a single Pt film to be $11 \pm 3$ nm, which is significantly larger compared to that of Pt adjacent to a magnetic layer.
description: 16 pages including Supplemental Material
Force networks and jamming in shear deformed sphere packings
Creators: name: Vinutha, H. A.
name: Sastry, Srikanth
Publisher: name: arXiv
Year: 2017
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The formation of self-organised structures that resist shear deformation have been discussed in the context of shear jamming and thickening[1-3], with frictional forces playing a key role. However, shear induces geometric features necessary for jamming even in frictionless packings[4]. We analyse conditions for jamming in such assemblies by solving force and torque balance conditions for their contact geometry. We demonstrate, and validate with frictional simulations, that the isostatic condition for mean contact number Z = D + 1 (for spatial dimension D = 2, 3) holds at jamming for both finite and infinite friction, above the random loose packing density. We show that the shear jamming threshold satisfies the marginal stability condition recently proposed for jamming in frictionless systems[5]. We perform rigidity percolation analysis[6,7] for D = 2 and find that rigidity percolation precedes shear jamming, which however coincides with the percolation of over-constrained regions, leading to the identification of an intermediate phase analogous to that observed in covalent glasses[8].
Model for the alpha and beta shear-mechanical properties of supercooled liquids and its comparison to squalane data
Creators: name: Hecksher, Tina
name: Olsen, Niels Boye
name: Dyre, Jeppe C.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: This paper presents data for supercooled squalane's frequency-dependent shear modulus covering frequencies from 10 mHz to 30 kHz and temperatures from 168 K to 190 K; measurements are also reported for the glass phase down to 146 K. The data reveal a strong mechanical beta process. A model is proposed for the shear response of supercooled liquids. The model is an electrical equivalent-circuit characterized by additivity of the dynamic shear compliances of the alpha and beta processes. The nontrivial parts of the alpha and beta processes are represented by a "Cole-Cole retardation element", resulting in the Cole-Cole compliance function well-known from dielectrics. The model, which assumes that the high-frequency decay of the alpha shear compliance loss varies with angular frequency as $ω^{-1/2}$, has seven parameters. Assuming time-temperature superposition for the alpha and the beta processes separately, the number of parameters varying with temperature is reduced to four. From the temperature dependence of the best-fit model parameters the following conclusions are drawn: 1) the alpha relaxation time conforms to the shoving model; 2) the beta relaxation loss-peak frequency is almost temperature independent; 3) the alpha compliance magnitude, which in the model equals the inverse of the instantaneous shear modulus, is only weakly temperature dependent; 4) the beta compliance magnitude decreases by a factor of three upon cooling in the temperature range studied. The final part of the paper briefly presents measurements of the dynamic adiabatic bulk modulus covering frequencies from 10 mHz to 10 kHz in the temperature range 172 K to 200 K. The data are qualitatively similar to the shear data by having a significant beta process. A single-order-parameter framework is suggested to rationalize these similarities.
Bottom-up configuration-interaction emulations of ultracold fermions in entangled optical plaquettes: building blocks of unconventional superconductivity
Creators: name: Brandt, Benedikt B.
name: Yannouleas, Constantine
name: Landman, Uzi
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A microscopic configuration-interaction (CI) methodology is introduced to enable bottom-up Schroedinger-equation emulation of unconventional superconductivity in ultracold optical traps. We illustrate the method by exploring the properties of Lithium-6 atoms in a single square plaquette in the hole-pairing regime, and by analyzing the entanglement (symmetry-preserving) and disentanglement physics (via symmetry-breaking, associated with the separation of charge and spin density waves) of two coupled plaquettes in the same regime. The single-occupancy RVB states contribute only partially to the exact many-body solutions, and the CI results map onto a Hubbard Hamiltonian, but not onto the double-occupancy-excluding t-J one. For the double-plaquette case, effects brought about by breaking the symmetry between two weakly-interacting plaquettes, either by distorting, or by tilting and detuning, one of the plaquettes with respect to the other, as well as spectral changes caused by increased coupling between the two plaquettes, are explored.
description: 14 pages with 9 color figures. Physical Review A (2017, in press)
Metals in the circumgalactic medium are out of ionization equilibrium due to fluctuating active galactic nuclei
Creators: name: Segers, Marijke C.
name: Oppenheimer, Benjamin D.
name: Schaye, Joop
name: Richings, Alexander J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We study the effect of a fluctuating active galactic nucleus (AGN) on the abundance of circumgalactic OVI in galaxies selected from the EAGLE simulations. We follow the time-variable OVI abundance in post-processing around four galaxies - two at $z=0.1$ with stellar masses of $M_{\ast} \sim 10^{10}$ M$_{\odot}$ and $M_{\ast} \sim 10^{11}$ M$_{\odot}$, and two at $z=3$ with similar stellar masses - out to impact parameters of twice their virial radii, implementing a fluctuating central source of ionizing radiation. Due to delayed recombination, the AGN leave significant `AGN proximity zone fossils' around all four galaxies, where OVI and other metal ions are out of ionization equilibrium for several megayears after the AGN fade. The column density of OVI is typically enhanced by $\approx 0.3-1.0$ dex at impact parameters within $0.3R_{\rm vir}$, and by $\approx 0.06-0.2$ dex at $2R_{\rm vir}$, thereby also enhancing the covering fraction of OVI above a given column density threshold. The fossil effect tends to increase with increasing AGN luminosity, and towards shorter AGN lifetimes and larger AGN duty cycle fractions. In the limit of short AGN lifetimes, the effect converges to that of a continuous AGN with a luminosity of $(f_{\rm duty}/100\%)$ times the AGN luminosity. We also find significant fossil effects for other metal ions, where low-ionization state ions are decreased (SiIV, CIV at $z=3$) and high-ionization state ions are increased (CIV at $z=0.1$, NeVIII, MgX). Using observationally motivated AGN parameters, we predict AGN proximity zone fossils to be ubiquitous around $M_{\ast} \sim 10^{10-11}$ M$_{\odot}$ galaxies, and to affect observations of metals in the circumgalactic medium at both low and high redshifts.
description: 17 pages, 11 figures (not including appendix), accepted for publication in MNRAS
Gluo-dissociation of Heavy Quarkonium in the Quark-Gluon Plasma Revisited
Creators: name: Chen, Shile
name: He, Min
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Using an effective Hamiltonian derived from the QCD multipole expansion, we calculate the cross sections of gluo-dissociation of heavy quarkonia in the quark-gluon plasma, by including both the chromo-electric dipole ($E_1$) as well as the chromo-magnetic dipole ($M_1$) transition mechanisms. While the former allows to reproduce the results from operator-product-expansion calculations in the Coulomb approximation, the latter as a novel contribution is shown to be significant at low energies close to the threshold. Using thus obtained cross sections, we further carry out a full calculation of the gluo-dissociation rates for various charmonia and bottomonia within a non-relativitic in-medium potential model. The $M_1$ contribution turns out to be most prominent for the $J/ψ$ and accounts for $\sim 10\%-25\%$ of the total ($E1+M1$) dissociation rate at temperatures close to the transition temperature.
description: 9 pages, 5 figures
A maximum magnetic moment to angular momentum conjecture
Creators: name: Barrow, John D.
name: Gibbons, G. W.
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: History and Philosophy of Physics (physics.hist-ph)
subject: FOS: Physical sciences

description: Conjectures play a central role in theoretical physics, especially those that assert an upper bound to some dimensionless ratio of physical quantities. In this paper we introduce a new such conjecture bounding the ratio of the magnetic moment to angular momentum in nature. We also discuss the current status of some old bounds on dimensionless and dimensional quantities in arbitrary spatial dimension. Our new conjecture is that the dimensionless Schuster-Wilson-Blackett number, cμ/JG^{(1/2)}, where μ is the magnetic moment and J is the angular momentum, is bounded above by a number of order unity. We verify that such a bound holds for charged rotating black holes in those theories for which exact solutions are available, including the Einstein-Maxwell theory, Kaluza-Klein theory, the Kerr-Sen black hole, and the so-called STU family of charged rotating supergravity black holes. We also discuss the current status of the Maximum Tension Conjecture, the Dyson Luminosity Bound, and Thorne's Hoop Conjecture.
description: 24 pages, no figures; to appear in Phys Rev D, refs added and typos corrected
IN_CERT Programme
Creators: name: Pomer, Mercè
name: Queralt Morros
name: Paredes, Roger
name: Vilaplana, Cristina
name: Mateu, Lourdes
name: Guerrero, Manel
name: Milne, Jo
name: Ancarola, Nora
name: Alcañiz, Adolf
Publisher: name: Zenodo
Year: 2021
Subjects: science
patients and public involvement
art

description: List and short summary of all the activities programmed within the IN_CERT initiative. IN_CERT is a public project promoted by Can Manyé Espai d'Art i Creació (Alella, Catalonia, Spain) and Alella's city council and conducted in partnership with the Germans Trias i Pujol Hospital (HUGTIP, http://www.hospitalgermanstrias.cat/en) and the Germans Trias i Pujol Research Institute (IGTP, http://www.germanstrias.org/). A stable group of artists and scientists have been meeting to discuss with other professionals about infectious diseases, outbreaks, the pandemic, the lock-down, death, the limits of the science, the ethical limits of research, how we face disease, etc. The working group has been working for one year. IN_CERT has resulted in several public activities jointly organized by the artists and the scientists, which will be held in several sites in Alella city and at the Hospital from 29th October 2021 until February 2022. The programme includes an exhibition, debates, a book and many other activities. Dr. Cristina Vilaplana (IGTP, CIBERES, SMA-TB EC-funded project coordinator) and Dr. Roger Paredes (HUGTIP, FLS, MISTRAL EC-funded project coordinator), together with Dr Lurdes Mateu (HUGTIP, FLS) have been the scientists involved in the working group. They have provided the perspective of tuberculosis disease and SMA-TB research (Vilaplana), HIV infection and MISTRAL research (Paredes) and Covid-19 (Mateu), and the impact of the pandemic on life and hospital and research activities (the 3 of them).
A new route to enhance the ferromagnetic transition temperature in diluted magnetic semiconductors
Creators: name: Pradhan, Kalpataru
name: Das, Subrat Kumar
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate the magnetic and the transport properties of diluted magnetic semiconductors using a spin-fermion Monte-Carlo method on a 3D lattice in the intermediate coupling regime. The ferromagnetic transition temperature $T_c$ shows an optimization behavior, first increases and then decreases, with respect to the absolute carrier density $p_{abs}$ for a given magnetic impurity concentration $x$, as seen in the experiment. Our calculations also show an insulator-metal-insulator transition across the optimum $p_{abs}$ where the $T_c$ is maximum. Remarkably, the optimum $p_{abs}$ values lie in a narrow range around 0.11 for all $x$ values and the ferromagnetic $T_c$ increases with $x$. We explain our results using the polaron percolation mechanism and outline a new route to enhance the ferromagnetic transition temperature in experiments.
description: 5 pages, 4 figures