cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Discrete breathers in nonlinear network models of proteins
Creators: name: Juanico, Brice
name: Sanejouand, Yves-Henri
name: Piazza, Francesco
name: Rios, Paolo de los
Publisher: name: arXiv
Year: 2007
Subjects: subject: Biomolecules (q-bio.BM)
subject: FOS: Biological sciences

description: We introduce a topology-based nonlinear network model of protein dynamics with the aim of investigating the interplay of spatial disorder and nonlinearity. We show that spontaneous localization of energy occurs generically and is a site-dependent process. Localized modes of nonlinear origin form spontaneously in the stiffest parts of the structure and display site-dependent activation energies. Our results provide a straightforward way for understanding the recently discovered link between protein local stiffness and enzymatic activity. They strongly suggest that nonlinear phenomena may play an important role in enzyme function, allowing for energy storage during the catalytic process.
description: 4 pages, 5 figures. Minor changes
Towards Sympathetic Laser Cooling and Detection of Single (Anti-)Proton
Creators: name: Meiners, T.
name: Niemann, M.
name: Paschke, A. -G.
name: Borchert, M.
name: Idel, A.
name: Mielke, J.
name: Voges, K.
name: Bautista-Salvador, A.
name: Lehnert, R.
name: Ulmer, S.
name: Ospelkaus, C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Current experimental efforts to test the fundamental CPT symmetry with single (anti-)protons are progressing at a rapid pace but are hurt by the nonzero temperature of particles and the difficulty of spin state detection. We describe a laser-based and quantum logic inspired approach to single (anti-)proton cooling and state detection.
description: Presented at the Seventh Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 20-24, 2016
A growing dynamo from a saturated Roberts flow dynamo
Creators: name: Tilgner, Andreas
name: Brandenburg, Axel
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Using direct simulations, weakly nonlinear theory and nonlinear mean-field theory, it is shown that the quenched velocity field of a saturated nonlinear dynamo can itself act as a kinematic dynamo. The flow is driven by a forcing function that would produce a Roberts flow in the absence of a magnetic field. This result confirms an analogous finding by F. Cattaneo & S. M. Tobias (arXiv:0809.1801) for the more complicated case of turbulent convection, suggesting that this may be a common property of nonlinear dynamos; see also the talk given also online at the Kavli Institute for Theoretical Physics (http://online.kitp.ucsb.edu/online/dynamo_c08/cattaneo). It is argued that this property can be used to test nonlinear mean-field dynamo theories.
description: 5 pages, 2 figures, accepted by MNRAS
security_smart_building_e_c_hasler.pdf
Creators: name: Hasler, Eva Christine
Publisher: name: figshare
Year: 2021
Subjects: subject: 109999 Technology not elsewhere classified
subject: FOS: Other engineering and technologies

description: Smart building provide intelligently connected, and central manageable solutions and are a global uptrend. This facilitates remote maintenance and enables cost reductions. These convenient possibilities increase the vulnerability and the likelihood of security threats in smart buildings. This thesis focuses on security threats that are caused by the complexity of human interaction which can be significantly reduced if smart building organizations implement security-relevant business processes to control this interaction. To implement these processes, they must be derived from a trusted source with proven best practice approaches such as security standards. The conducted literature research reveals that there is no, or only marginally mentioned coverage of security threats caused by the complexity of human interaction. Qualitative content analysis shows that relevant standards provide controls to reduce the risk of security threats. The wide-spread information and the comprehensive character of most security standards make it difficult for smart building organizations to gain a clear overview. As a result, they do seldom use standards as a basis to develop and apply security processes. In conclusion, security standards provide the required best practices, but the information is not yet sufficiently accessible for smart building organizations. Furthermore, the topic of security issues caused by human interaction needs more coverage in future scientific work.
Melting curve and Hugoniot of molybdenum up to 400 GPa by ab initio simulations
Creators: name: Cazorla, C.
name: Gillan, M. J.
name: Taioli, S.
name: Alfè, D.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report ab initio calculations of the melting curve and Hugoniot of molybdenum for the pressure range 0-400 GPa, using density functional theory (DFT) in the projector augmented wave (PAW) implementation. We use the ``reference coexistence'' technique to overcome uncertainties inherent in earlier DFT calculations of the melting curve of Mo. Our calculated melting curve agrees well with experiment at ambient pressure and is consistent with shock data at high pressure, but does not agree with the high pressure melting curve from static compression experiments. Our calculated P(V) and T(P) Hugoniot relations agree well with shock measurements. We use calculations of phonon dispersion relations as a function of pressure to eliminate some possible interpretations of the solid-solid phase transition observed in shock experiments on Mo.
description: 8 pages, 6 figures
Highly cited articles in “Zeitschrift für Medizinische Physik”
Creators: name: Treutwein, Marius
name: Schad, Lothar
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: impact factor, citations, web of science, scopus
subject: 530 Physik
subject: 610 Medizin

description: This editorial describes the publishing guidelines of the journal "Zeitschrift für Medizinische Physik" and the development of its impact factors. The articles with the most number of citations in the databases of ISI Web of Science™ and Scopus are listed.
description: NOTICE: this is the author’s version of a work that was accepted for publication in . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication.
The stellar beta-decay rate of 134Cs and its impact on the Barium nucleosynthesis in the s process
Creators: name: Li, Kuo-Ang
name: Qi, Chong
name: Lugaro, Maria
name: López, Andrés Yagüe
name: Karakas, Amanda I.
name: Hartogh, Jacqueline den
name: Gao, Bing-Shui
name: Tang, Xiao-Dong
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We have calculated the stellar $β$-decay rate of the important s-process branching point ${}^{134}$Cs based on the state of the art shell model calculations. At typical $s$-process temperatures ($T\sim$ 0.2-0.3 GK), our new rate is one order of magnitude lower than the widely-used rate from Takahashi and Yokoi (hereafter TY87). The impact on the nucleosynthesis in AGB stars is investigated with various masses and metallicities. Our new decay rate leads to an overall decrease in the ${}^{134}$Ba/${}^{136}$Ba ratio, and well explains the measured ratio in meteorities without introducing the $i$ process. We also derive the elapsed time from the last AGB nucleosynthetic event that polluted the early Solar System to be $>$28 Myr based on the ${}^{135}$Cs/${}^{133}$Cs ratio, which is consistent with the elapsed times derived from ${}^{107}$Pd and ${}^{182}$Hf. The $s$-process abundance sum of ${}^{135}$Ba and ${}^{135}$Cs is found to increase, resulting in a smaller $r$-process contribution of ${}^{135}$Ba in the Solar System.
description: accepted for publication in Astrophysical Journal Letters, 2021
Unidirectional Charge Instability of the d-wave RVB Superconductor
Creators: name: Raczkowski, Marcin
name: Capello, Manuela
name: Poilblanc, Didier
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Starting from a uniform d-wave superconducting phase we study the energy cost due to imposed unidirectional defects with a vanishing pairing amplitude. Both renormalized mean-field theory and variational Monte Carlo calculations within the t-J model yield that the energies of inhomogeneous and uniform phases are very close to each other. This suggests that small perturbations in the microscopic Hamiltonian, might lead to inhomogeneous superconducting phases in real materials as observed in recent scanning tunneling microscopy on Ca_{2-x}Na_xCuO_2Cl_2.
description: 5 pages. 2 figures
Conflicts in providing security in computer-based message systems
Creators: name: Kusalik, Anthony Joseph
Publisher: name: University of British Columbia
Year: 2010

description: This thesis identifies and discusses problems which develop when guaranteed message security is to be incorporated into the design of a computer-based message system. The conflicts are the result of following existing security and message system design models, the basic one-way nature of the communications provided, and the desire to provide customarily expected functionality. Solutions to some of these problems are presented. A message system model is given, and an implementation following the model is described and evaluated. The ideas of researchers primarily concerned with computer system or network security differ from those in the area of computer-based message system design. Views vary on the correct loaction within a message system of facilities for data encryption, delivery confirmation, and duplicate message suppression. These differences of approach are discussed.
Fast cooling and internal heating in hyperon stars
Creators: name: Anzuini, F.
name: Melatos, A.
name: Dehman, C.
name: Viganò, D.
name: Pons, J. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Neutron star models with maximum mass close to $2 \ M_{\odot}$ reach high central densities, which may activate nucleonic and hyperon direct Urca neutrino emission. To alleviate the tension between fast theoretical cooling rates and thermal luminosity observations of moderately magnetized, isolated thermally-emitting stars (with $L_γ \gtrsim 10^{31}$ erg s$^{-1}$ at $t \gtrsim 10^{5.3}$ yr), some internal heating source is required. The power supplied by the internal heater is estimated for both a phenomenological source in the inner crust and Joule heating due to magnetic field decay, assuming different superfluidity models and compositions of the outer stellar envelope. It is found that a thermal power of $W(t) \approx 10^{34}$ erg s$^{-1}$ allows neutron star models to match observations of moderately magnetized, isolated stars with ages $t \gtrsim 10^{5.3}$ yr. The requisite $W(t)$ can be supplied by Joule heating due to crust-confined initial magnetic configurations with (i) mixed poloidal-toroidal fields, with surface strength $B_{\textrm{dip}} = 10^{13}$ G at the pole of the dipolar poloidal component and $\sim 90$ per cent of the magnetic energy stored in the toroidal component; and (ii) poloidal-only configurations with $B_{\textrm{dip}} = 10^{14}$ G.
description: 15 pages, 9 figures. Accepted for publication in MNRAS
A template bank to search for gravitational waves from inspiralling compact binaries: II. Phenomenological model
Creators: name: Cokelaer, Thomas
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Matched filtering is used to search for gravitational waves emitted by inspiralling compact binaries in data from ground-based interferometers. One of the key aspects of the detection process is the deployment of a set of templates, also called a template bank, to cover the astrophysically interesting region of the parameter space. In a companion paper, we described the template-bank algorithm used in the analysis of LIGO data to search for signals from non-spinning binaries made of neutron star and/or stellar-mass black holes; this template bank is based upon physical template families. In this paper, we describe the phenomenological template bank that was used to search for gravitational waves from non-spinning black hole binaries (from stellar mass formation) in the second, third and fourth LIGO science runs. We briefly explain the design of the bank, whose templates are based on a phenomenological detection template family. We show that this template bank gives matches greater than 95% with the physical template families that are expected to be captured by the phenomenological templates.
description: 10 pages, 9 figures
CPT test with (anti-)proton magnetic moments based on quantum logic cooling and readout
Creators: name: Niemann, M.
name: Paschke, A. -G.
name: Dubielzig, T.
name: Ulmer, S.
name: Ospelkaus, C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Dehmelt and VanDyck's famous 1987 measurement of the electron and positron g-factor is still the most precise g-factor comparison in the lepton sector, and a sensitive test of possible CPT violation. A complementary g-factor comparison between the proton and the antiproton is highly desirable to test CPT symmetry in the baryon sector. Current experiments, based on Dehmelt's continuous Stern-Gerlach effect and the double Penning-trap technique, are making rapid progress. They are, however, extremely difficult to carry out because ground state cooling using cryogenic techniques is virtually impossible for heavy baryons, and because the continous Stern-Gerlach effect scales as $μ$/m, where m is the mass of the particle and $μ$ its magnetic moment. Both difficulties will ultimately limit the accuracy. We discuss experimental prospects of realizing an alternative approach to a g-factor comparison with single (anti)protons, based on quantum logic techniques proposed by Heinzen and Wineland and by Wineland et al. The basic idea is to cool, control and measure single (anti-)protons through interaction with a well-controlled atomic ion.
description: Presented at the Sixth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 17-21, 2013
An Abundance of Heterotic Vacua
Creators: name: Gabella, Maxime
name: He, Yang-Hui
name: Lukas, Andre
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We explicitly construct the largest dataset to date of heterotic vacua arising from stable vector bundles on Calabi-Yau threefolds. Focusing on elliptically fibered Calabi-Yau manifolds with spectral cover bundles, we show that the number of heterotic models with non-zero number of generations is finite. We classify these models according to the complex base of their Calabi-Yau threefold and to the unification gauge group that they preserve in four dimensions. This database of the order of $10^7$ models, which includes potential Standard Model candidates, is subjected to some preliminary statistical analyses. The additional constraint that there should be three net generations of particles gives a dramatic reduction of the number of vacua.
description: 27 pages, 12 figures, added references
An analytic expression for the optical exciton transition rates in the polaron frame
Creators: name: Rouse, Dominic M
name: Gauger, Erik M
name: Lovett, Brendon W
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: When an optical emitter is strongly coupled to a vibrational bath the polaron transformation is often used to permit an accurate second-order Redfield master equation. However, the optical transition rates in the polaron frame are not analytic and approximations typically need to be made which result in the loss of anything other than simple additive effects of the two baths. In this paper, we derive an intuitive analytic expression for the polaron frame optical transition rates by means of a finite mode truncation of the vibrational bath. Using this technique, calculations of the transition rates converge for only a few modes in the truncated spectral density, and capture non-additive effects such as population inversion of a two-level system.
description: 12 pages, 6 figures
Non-normal Hamiltonian dynamics in quantum systems and its realization on quantum computers
Creators: name: Okuma, Nobuyuki
name: Nakagawa, Yuya O.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The eigenspectrum of a non-normal matrix, which does not commute with its Hermitian conjugate, is a central issue of non-Hermitian physics that has been extensively studied in the past few years. There is, however, another characteristic of a non-normal matrix that has often been overlooked: the pseudospectrum, or the set of spectra under small perturbations. In this paper, we study the dynamics driven by the non-normal matrix (Hamiltonian) realized as a continuous quantum trajectory of the Lindblad master equation in open quantum systems and point out that the dynamics can reveal the nature of unconventional pseudospectrum of the non-normal Hamiltonian. In particular, we focus on the transient dynamics of the norm of an unnormalized quantum state evolved with the non-normal Hamiltonian, which is related to the probability for observing the trajectory with no quantum jump. We formulate the transient suppression of the decay rate of the norm due to the pseudospectral behavior and derive a non-Hermitian/non-normal analog of the time-energy uncertainty relation. We also consider two methods to experimentally realize the non-normal dynamics and observe our theoretical findings on quantum computers: one uses a technique to realize non-unitary operations on quantum circuits and the other leverages a quantum-classical hybrid algorithm called variational quantum simulation. Our demonstrations using cloud-based quantum computers provided by IBM Quantum exhibit the frozen dynamics of the norm in transient time, which can be regarded as a non-normal analog of the quantum Zeno effect.
description: 16 pages, 5 figures
Frobenius statistical manifolds & geometric invariants
Creators: name: Combe, Noemie
name: Combe, Philippe
name: Nencka, Hanna
Publisher: name: arXiv
Year: 2021
Subjects: subject: Algebraic Geometry (math.AG)
subject: Information Theory (cs.IT)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: 53B99, 62B10, 60D99, 53D45

description: In this paper, we explicitly prove that statistical manifolds, related to exponential families and with flat structure connection have a Frobenius manifold structure. This latter object, at the interplay of beautiful interactions between topology and quantum field theory, raises natural questions, concerning the existence of Gromov--Witten invariants for those statistical manifolds. We prove that an analog of Gromov--Witten invariants for those statistical manifolds (GWS) exists. Similarly to its original version, these new invariants have a geometric interpretation concerning intersection points of para-holomorphic curves. However, it also plays an important role in the learning process, since it determines whether a system has succeeded in learning or failed.
description: 8 pages
Confinement in the q-state Potts field theory
Creators: name: Delfino, Gesualdo
name: Grinza, Paolo
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The q-state Potts field theory describes the universality class associated to the spontaneous breaking of the permutation symmetry of q colors. In two dimensions it is defined up to q=4 and exhibits duality and integrability away from critical temperature in absence of magnetic field. We show how, when a magnetic field is switched on, it provides the simplest model of confinement allowing for both mesons and baryons. Deconfined quarks (kinks) exist in a phase bounded by a first order transition on one side, and a second order transition on the other. The evolution of the mass spectrum with temperature and magnetic field is discussed.
description: 21 pages, 8 figures. v2: references added
Tidal disruption and ignition of white dwarfs by moderately massive black holes
Creators: name: Rosswog, S.
name: Ramirez-Ruiz, E.
name: Hix, R.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present a numerical investigation of the tidal disruption of white dwarfs by moderately massive black holes, with particular reference to the centers of dwarf galaxies and globular clusters. Special attention is given to the fate of white dwarfs of all masses that approach the black hole close enough to be disrupted and severely compressed to such extent that explosive nuclear burning can be triggered. Consistent modeling of the gas dynamics together with the nuclear reactions allows for a realistic determination of the explosive energy release. In the most favorable cases, the nuclear energy release may be comparable to that of typical type Ia supernovae. Although the explosion will increase the mass fraction escaping on hyperbolic orbits, a good fraction of the debris remains to be swallowed by the hole, causing a bright soft X-ray flare lasting for about a year. Such transient signatures, if detected, would be a compelling testimony for the presence of a moderately mass black hole (below $10^5 M_\odot$).
description: 38 pages, 19 figures, further simulations added
Towards Sympathetic Cooling of Single (Anti-)Protons
Creators: name: Meiners, T.
name: Niemann, M.
name: Mielke, J.
name: Borchert, M.
name: Pulido, N.
name: Cornejo, J. M.
name: Ulmer, S.
name: Ospelkaus, C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We present methods to manipulate and detect the motional state and the spin state of a single antiproton or proton which are currently under development within the BASE (Baryon Antibaryon Symmetry Experiment) collaboration. These methods include sympathetic laser cooling of a single (anti-)proton using a co-trapped atomic ion as well as quantum logic spectroscopy with the two particles and could be implemented within the collaboration for state preparation and state readout in the antiproton $g$-factor measurement experiment at CERN. In our project, these techniques shall be applied using a single $^9\text{Be}^+$ ion as the atomic ion in a Penning trap system at a magnetic field of 5 T. As an intermediate step, a controlled interaction of two beryllium ions in a double-well potential as well as sympathetic cooling of one ion by the other shall be demonstrated.
description: Proceedings of the 13th International Conference on Low Energy Antiproton Physics (LEAP 2018) Paris, France, 12-16 March 2018
Test of the HADES Electromagnetic Calorimeter modules on photon beam
Creators: name: Svoboda, O.
name: Galatyuk, T.
name: Kardan, B.
name: Korcyl, G.
name: König, W.
name: Neiser, A.
name: Linev, S.
name: Ott, P.
name: Otte, P.
name: Petukhov, O.
name: Pietraszko, J.
name: Ramos, P.
name: Rost, A.
name: Thomas, A.
name: Tlusty, P.
name: Traxler, M.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2014
Subjects: Physics

description: GSI Scientific Report 2013 - GSI Report 2014-1
Vanishing viscosity and the accumulation of vorticity on the boundary
Creators: name: Kelliher, James P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 76D05; 76B99; 76D99

description: We say that the vanishing viscosity limit holds in the classical sense if the velocity for a solution to the Navier-Stokes equations converges in the energy norm uniformly in time to the velocity for a solution to the Euler equations. We prove, for a bounded domain in dimension 2 or higher, that the vanishing viscosity limit holds in the classical sense if and only if a vortex sheet forms on the boundary.
BioMekanika 1
Creators: name: Baño, Dexter Jr., P.
Publisher: name: Zenodo
Year: 2023
Subjects: biodiesel
biofuel
alternative fuel

description: The current utility model relates to a vending machine that can produce biodiesel from wasted cooking oil and dispense it to customers. This will be called, “BioMekanika 1". The device is made up of a number of interconnected components, such as a depositor for spent cooking oil, a tank for used cooking oil, a tank for methanol and sodium hydroxide, a tank for the reactor, a heat coil, and a number of pipes with filters. A rectangular enclosure encloses the entire apparatus.
Possibility of a modification of life time of radioactive elements by magnetic monopoles
Creators: name: Kostenko, B. F.
name: Yuriev, M. Z.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: A simple explanation of the fact that light magnetic monopoles have not been observed at accelerator experiments is given. It is based on a possibility of violation of C invariance in the electromagnetic interactions. Because of the difficulty of monopole registration, two interconnected problems arise: to formulate a theory describing monopole production (it should include a new force beyond the Standard Model of electroweak interaction), and to point the way to monopole observation. We consider a possibility, closely related to some experiments, of a modification of life time of radioactive elements by magnetic monopoles. The first part of the article is devoted to purely electromagnetic impact of monopoles, caused by the vertex M --> M + gamma. The second part, more speculative one, is based on experimental evidences in favour of the existence of some axial vector currents, responsible for a new force, which can stimulate, or suppress, decays of radioactive elements.
description: Invited lecture at Colloquium "Magnetic monopoles, Physical symmetries, Nodal electric fields", Peyresq, France, 9-16 August 2007
Exact Solutions of the Equations of Relativistic Hydrodynamics Representing Potential Flows
Creators: name: Borshch, Maxim S.
name: Zhdanov, Valery I.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mathematical Physics (math-ph)
subject: Astrophysics (astro-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences
subject: 76Y05; 83C15; 83A05

description: We use a connection between relativistic hydrodynamics and scalar field theory to generate exact analytic solutions describing non-stationary inhomogeneous flows of the perfect fluid with one-parametric equation of state (EOS) $p = p(ε)$. For linear EOS $p = κε$ we obtain self-similar solutions in the case of plane, cylindrical and spherical symmetries. In the case of extremely stiff EOS ($κ=1$) we obtain ''monopole + dipole'' and ''monopole + quadrupole'' axially symmetric solutions. We also found some nonlinear EOSs that admit analytic solutions.
description: This is a contribution to the Proc. of the Seventh International Conference ''Symmetry in Nonlinear Mathematical Physics'' (June 24-30, 2007, Kyiv, Ukraine), published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA/
Colour manipulation of digital images
Creators: name: Palmer, Patricia Jane Carmel
Publisher: name: University of British Columbia
Year: 2010

description: Currently, standard enhancement of three-channel colour digital imagery is not performed in a general fashion; it is dependent on the particular colour device used to display the imagery. By introducing a colour transformation, the enhancement can be standardized and therefore be defined in terms of other devices. In addition, the colour transformation can be defined such that the perceptual attributes of colour associated with an image are more easily manipulated. The purpose of this work is to examine a variety of such colour transformations and implement a subset of these on a colour CRT.
First-principles calculations of phonon transport across a vacuum gap
Creators: name: Tokunaga, Takuro
name: Arai, Masao
name: Kobayashi, Kazuaki
name: Hayami, Wataru
name: Suehara, Shigeru
name: Shiga, Takuma
name: Park, Keunhan
name: Francoeur, Mathieu
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Phonon transport across a vacuum gap separating intrinsic silicon crystals is predicted via the atomistic Green's function method combined with first-principles calculations of all interatomic force constants. The overlap of electron wave functions in the vacuum gap generates weak covalent interaction between the silicon surfaces, thus creating a pathway for phonons. Phonon transport, dominated by acoustic modes, exceeds near-field radiation for vacuum gaps smaller than ~ 1 nm. The first-principles-based approach proposed in this work is critical to accurately quantify the contribution of phonon transport to heat transfer in the extreme near field.
description: 31 pages, 4 figures, 4 supplemental figures
Social Network Sites for Medical Physicists
Creators: name: Treutwein, Marius
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: Social Network Sites; Web 2.0; Medical Physics
subject: 530 Physik
subject: 600 Technik
subject: 610 Medizin

description: Social Network Sites (SNS) as a part of Web 2.0 gain increasing importance in social life. There are different types of SNS being more or less adapted to the requirements of professionals. For a selection of six SNS features and services were regarded in respect to the applicability in the professional life, using medical physicists as an example. Services as groups, calendar, literature services, and career functions prove to be of particular convenience. As all Web 2.0 services SNS depend on the contributions and operations of their users.
description: Der herausgebende Verlag und die Zeitschrift scheinen mittlerweile nicht mehr zu existieren. (31.5.2017)
Silvopasture in Central New York, Galicia and Central Argentina
Creators: name: Mosquera-Losada M., R.
name: Chatrchyan, A.
name: Chedzoy B. J
Publisher: name: Zenodo
Year: 2019
Subjects: environment benefits
productive benefits
social benefits

description: The Sierra Mountains of Central Argentina: Afforestations in Argentina converted some
areas in silvopasture. Major benefits include: (i) Decreased flash flooding through increased
precipitation infiltration (ii) Rapid improvements of soil health by OM and nutrient deposition(iii)
increase rural employment (iv) Production diversification. (v) Higher stocking capacities than
treeless areas (v) Silvopasture provides shelter for livestock during extreme weather events
(vi) Improved silvopasture rotational grazing increases animal performance and health and
plant richness.
Central New York: Livestock farms in New York are typically a mix of pasture and forest.
Major benefits of silvopasture are: (i) Control tool of invasive forest plants (ii) Increase farmland
use and diversification leading to a greater viability. (iii) Soil health improvement (iv) Improved
water infiltration in soils (v) Reduced extreme weather events livestock exposure and animal
confination (vi) Greater forage drought resilience(vii) Reduced pest issues (viii) Greater resilience.
Galicia: Silvopasture benefits in Galicia are (i) Feeding animals during shortage feed periods (ii)
Increasing short, medium and long term productivity (iii)Reducing fire risk and GHG emissions
(iv) Increasing biodiversity (v) Reducing water contamination in agricultural lands (vi) Improving
soil water infiltration (vii) Improves landscape beauty (viii) Increasing productivity, rural development
and community resilience.
Harmonic oscillator eigenfunction expansions, quantum dots, and effective interactions
Creators: name: Kvaal, Simen
Publisher: name: arXiv
Year: 2008
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We give a thorough analysis of the convergence properties of the configuration-interaction method as applied to parabolic quantum dots among other systems, including \emph{a priori} error estimates. The method converges slowly in general, and in order to overcome this, we propose to use an effective two-body interaction well-known from nuclear physics. Through numerical experiments we demonstrate a significant increase in accuracy of the configuration interaction method.
description: 3 figures
Simultaneous approximation of a real number by all conjugates of an algebraic number
Creators: name: Alain, Guillaume
Publisher: name: arXiv
Year: 2007
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11J13, 11J70

description: Using a method of H. Davenport and W. M. Schmidt, we show that, for each positive integer n, the ratio 2/n is the optimal exponent of simultaneous approximation to real irrational numbers 1) by all conjugates of algebraic numbers of degree n, and 2) by all but one conjugates of algebraic integers of degree n+1.
description: 7 pages
Agroforestry Policy on the Atlantic area
Creators: name: Mosquera-Losada M., R.
name: Curran, E.
name: McAdam, J.
Publisher: name: Zenodo
Year: 2019
Subjects: CAP
carbon
climate change

description: The Western part of Europe is dominated by Atlantic weather conditions which are associated
with high rain fall conditions of over 600 mm to 2500 mm per year. This precipitation provides
excellent conditions for high productivity for all types of crops which are mainly associated
with forestry and to permanent grasslands in the Western part of Europe. There is also a temperature
gradient from the North to the South that creates growth restrictions associated with
cold and droughts in areas like Ireland and Galicia. Both areas have enormous potential to increase
agroforestry use and promote more sustainable land management. Ireland has a large
number of hedgerows that help reduce the negative impact of winds in grassland production
but also contributes to improved animal welfare. Galicia has a 70% of its land allocated to
forestry and should use livestock to reduce forest fires which results in over 100,000 ha of
burned land in only a few days every decade when weather conditions become increasingly
negative. The benefits that silvopastoralism could provide are even greater considering the
rising temperatures and the appearance of extreme events due to climate change. Increasing
forest cover in Ireland and delivering agricultural products (livestock) can be achieved on the
same piece of land, while access to the land is prolonged through the presence of trees and
the enhanced drainage they provide. The potential for agroforestry to mitigate the negative
effects of wildfires in Ireland is also recognised. Increasing forest land used by livestock in
Galicia is essential to increase income and rural development as livestock produces a short
and medium term income to farmers that otherwise cannot live exclusively from the benefits
of forestry. Tree species selection and tree density becomes a key issue in both cases.
Broadleaves such as oak ,ash (some species), birch, willow, walnut, poplar or cherry are excellent
species because they can provide feed in the autumn or when pruned and shaped to
obtain high value timber trees. In addition they can protect water, intercepting silt and nutrient
runoff and can increase soil fertility as they incorporate leaves every year into the soil increasing
nutrient recycling and carbon storage. When selected the species it is important to take
into consideration the time when the leaves appear, the capacity of generating epicornic buds,
fruit and nuts, but also its management such as the distribution within the plot or the timing
for thinning and final harvests as this will affect the development of both livestock and forest
stand. The management of light will be critical too as the trees mature and shade increased
it is important that there is enough light for grass to thrive. In spite of the known positive impacts
silvopastural agroforestry systems could have in both areas, the number of measures
promoting them is still rather small.
A highly magnetised and rapidly rotating white dwarf as small as the Moon
Creators: name: Caiazzo, Ilaria
name: Burdge, Kevin B.
name: Fuller, James
name: Heyl, Jeremy
name: Kulkarni, S. R.
name: Prince, Thomas A.
name: Richer, Harvey B.
name: Schwab, Josiah
name: Andreoni, Igor
name: Bellm, Eric C.
name: Drake, Andrew
name: Duev, Dmitry A.
name: Graham, Matthew J.
name: Helou, George
name: Mahabal, Ashish A.
name: Masci, Frank J.
name: Smith, Roger
name: Soumagnac, Maayane T.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: White dwarfs represent the last stage of evolution of stars with mass less than about eight times that of the Sun and, like other stars, are often found in binaries. If the orbital period of the binary is short enough, energy losses from gravitational-wave radiation can shrink the orbit until the two white dwarfs come into contact and merge. Depending on the component masses, the merger can lead to a supernova of type Ia or result in a massive white dwarf. In the latter case, the white dwarf remnant is expected to be highly magnetised because of the strong magnetic dynamo that should arise during the merger, and be rapidly spinning from the conservation of the orbital angular momentum. Here we report observations of a white dwarf, ZTF J190132.9+145808.7, that exhibits these properties, but to an extreme: a rotation period of 6.94 minutes, a magnetic field ranging between 600 megagauss and 900 megagauss over its surface, and a stellar radius of about 2,100 km, slightly larger than the radius of the Moon. Such a small radius implies that the star's mass is close to the maximum white-dwarf mass, or Chandrasekhar mass. ZTF J190132.9+145808.7 is likely to be cooling through the Urca processes (neutrino emission from electron capture on sodium) because of the high densities reached in its core.
description: 37 pages, 9 figures, published in Nature on June 30, 2021
The Remarkable Spin-down and Ultra-fast Outflows of the Highly-Pulsed Supersoft Source of Nova Hercules 2021
Creators: name: Drake, Jeremy J.
name: Ness, Jan-Uwe
name: Page, Kim L.
name: Luna, G. J. M.
name: Beardmore, Andrew P.
name: Orio, Marina
name: Osborne, Julian P.
name: Mroz, Przemek
name: Starrfield, Sumner
name: Banerjee, Dipankar P. K.
name: Balman, Solen
name: Darnley, M. J.
name: Bhargava, Y.
name: Dewangan, G. C.
name: Singh, K. P.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Nova Her 2021 (V1674 Her), which erupted on 2021 June 12, reached naked-eye brightness and has been detected from radio to $γ$-rays. An extremely fast optical decline of 2 magnitudes in 1.2 days and strong Ne lines imply a high-mass white dwarf. The optical pre-outburst detection of a 501.42s oscillation suggests a magnetic white dwarf. This is the first time that an oscillation of this magnitude has been detected in a classical nova prior to outburst. We report X-ray outburst observations from {\it Swift} and {\it Chandra} which uniquely show: (1) a very strong modulation of super-soft X-rays at a different period from reported optical periods; (2) strong pulse profile variations and the possible presence of period variations of the order of 0.1-0.3s; and (3) rich grating spectra that vary with modulation phase and show P Cygni-type emission lines with two dominant blue-shifted absorption components at $\sim 3000$ and 9000 km s$^{-1}$ indicating expansion velocities up to 11000 km s$^{-1}$. X-ray oscillations most likely arise from inhomogeneous photospheric emission related to the magnetic field. Period differences between reported pre- and post-outburst optical observations, if not due to other period drift mechanisms, suggest a large ejected mass for such a fast nova, in the range $2\times 10^{-5}$-$2\times 10^{-4} M_\odot$. A difference between the period found in the {\it Chandra} data and a reported contemporaneous post-outburst optical period, as well as the presence of period drifts, could be due to weakly non-rigid photospheric rotation.
description: 11 pages, 5 figures. Accepted for publication in Astrophysical Journal Letters
Compressed Monte Carlo with application in particle filtering
Creators: name: Martino, Luca
name: Elvira, Víctor
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation (stat.CO)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Bayesian models have become very popular over the last years in several fields such as signal processing, statistics, and machine learning. Bayesian inference requires the approximation of complicated integrals involving posterior distributions. For this purpose, Monte Carlo (MC) methods, such as Markov Chain Monte Carlo and importance sampling algorithms, are often employed. In this work, we introduce the theory and practice of a Compressed MC (C-MC) scheme to compress the statistical information contained in a set of random samples. In its basic version, C-MC is strictly related to the stratification technique, a well-known method used for variance reduction purposes. Deterministic C-MC schemes are also presented, which provide very good performance. The compression problem is strictly related to the moment matching approach applied in different filtering techniques, usually called as Gaussian quadrature rules or sigma-point methods. C-MC can be employed in a distributed Bayesian inference framework when cheap and fast communications with a central processor are required. Furthermore, C-MC is useful within particle filtering and adaptive IS algorithms, as shown by three novel schemes introduced in this work. Six numerical results confirm the benefits of the introduced schemes, outperforming the corresponding benchmark methods. A related code is also provided.
Verification of IMRT: Techniques and Problems
Creators: name: Bogner, Ludwig
name: Scherer, Josef
name: Treutwein, Marius
name: Hartmann, Matthias
name: Gum, Franz
name: Amediek, Axel
Publisher: name: Universität Regensburg
Year: 2004
Subjects: subject: IMRT,Verification,QA ,Monte Carlo, TPS commissioning,Verifikation,QS,TPS-Kommissionierung
subject: 530 Physik
subject: 610 Medizin

description: Purpose:
IMRT (intensity-modulated radiotherapy) verification techniques are reviewed together with investigations demonstrating the intrinsic verification problems.
Material and Methods:
Different IMRT verification procedures for either class solutions or individual patients are demonstrated. Among the latter are techniques like fluence or three-dimensional (3-D) dose distribution verification within a transfer phantom. Different radiographic films and absolute dose probes are investigated for their suitability. Finally, Monte Carlo techniques (XVMC/VEF) are used for error detection and IMRT verification.
Results:
During introduction of clinical IMRT for head and neck (H&N) tumors, we concurrently applied fluence, relative, and absolute dose measurement. While fluence and relative dose are in rather good agreement with calculations, absolute dose is always low when compared to the TPS (TMS 6.1A, Nucletron B.V.) by 5–7%. This deviation seems to depend not on the number of segments, but can strongly depend on MLC misalignment. Further investigations have revealed the importance of a detailed commissioning of the TPS down to the small-field range using diamond or diode probes and its detailed verification. In addition, simple tests have shown that dose calculation approximations in the IMRT option of TMS are one major source of the dose deviation. XVMC/VEF does not use such approximations.
Conclusion:
The procedure starts with a detailed TPS commissioning and verification process. Different verification methods are recommended during clinical IMRT implementation phase, in order to locate sources of error. Later on, a minimal program could consist of a fluence or relative dose verification procedure with few films and absolute dose measurement, followed by an intensive MLC quality assurance (QA). Inverse Monte Carlo systems, like IMCO++/IKO or Hyperion, seem to be able to reduce the effort.
Agroforestry promotion in Europe through forestry measures
Creators: name: Santiago-Freijanes
name: A. Pisanelli
name: M. Rois-Díaz
name: Aldrey-Vázquez A
name: Rigueiro-Rodríguez A
name: Pantera A
name: Lojka B
name: Ferreiro-Domínguez N
name: Mosquera-Losada MR.
Publisher: name: Zenodo
Year: 2019
Subjects: POLICY
CAP
Measures

description: Agroforestry is considered a sustainable form of land management that optimizes the use of
natural resources (nutrients, radiation, water). Agroforestry was a traditional land use system
in Europe before modern times. However, before the sixties land intensification and consolidation
destroyed millions of trees all over Europe. On the contrary, some good examples
of agroforestry promotion are found in Eastern European countries in order to reduce the
effect of extreme events such as winds, flooding at the beginning and mid of the last century.
In Western European countries, the introduction of trees in the land has been promoted by
agroforestry, afforestation and reforestation at the end of the last century. Afforestation of
agricultural lands have been the most successful CAP measure (over 1 million hectares) while
agroforestry measures were not extensively adopted which may be explained by the funds
associated to afforestation measure which compensated the losses of income 15 or 20 years
in afforested lands. Agroforestry was poorly adopted in the CAP 2007–2013, having a better
success in the CAP 2014–2020 due to the recognition of woody vegetation and the compensation
of 5 years given for maintenance once agroforestry is established. However, policy rules
ensuring Pillar I payment when agroforestry measure is adopted such as a management plans
ensuring that maximum tree density (100 trees per hectare) is not reached, should be pursued.