cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Incidence and rehabilitation of lower limb amputation in Canada, and feasibility of a novel training program
Creators: name: Imam, Bita
Publisher: name: University of British Columbia
Year: 2017

description: Background: There is a dearth of evidence about lower limb amputation (LLA) incidence, rehabilitation, and practice in Canada. Such data are crucial for assessing the burden of the disability and making informed healthcare decisions. We know from the literature that the current resource-intensive rehabilitation model is costly and perhaps not sustainable. This highlights the need for exploring interventions that are less resource-intensive and, therefore, more cost-effective. Purpose: To gain an understanding about the incidence of LLA, current practices, and rehabilitation services provided in Canada and to design and evaluate a novel approach that may ultimately provide cost-effective LLA rehabilitation. Methods: Five studies were conducted. Studies 1-2) analyses of Canadian data to determine the incidence of LLA and the provision of inpatient rehabilitation services from 2006 to 2011; studies 3-4) a Canadian survey to describe prosthetic rehabilitation practices and to explore therapists’ perspectives about the use of commercial games, particularly the Nintendo Wii Fit, in rehabilitation; and study 5) a feasibility randomized controlled trial (RCT) to evaluate the use of Wii Fit intervention (named Wii.n.Walk) in LLA rehabilitation. Results: The age-adjusted incidence of LLA was 22.9 per 100,000 individuals. Although there was a decline in the incidence rates, the number of LLAs increased for older age categories. In total, 18.0% (n=2,902/16,114) of the individuals received inpatient rehabilitation in Canada over the study years. When asked about the use of commercial games, 43.9% (n=36/82) of the therapists indicated that they use the Wii Fit in rehabilitation. Our feasibility RCT showed the intervention adherence was 83.4%. No adverse events occurred. Conclusions: Although the age-adjusted incidence rates have declined, the number of LLAs has increased in individuals older than 50. Given the increase in number of LLAs and the fact that only 18% of individuals receive inpatient rehabilitation, there is a need for other service deliveries. The Wii Fit is prevalently used in prosthetic rehabilitation in Canada and was found to be feasible for LLA rehabilitation. A future powered RCT is required to provide more evidence about the efficacy and cost-effectiveness of the Wii Fit in prosthetic rehabilitation.
Multiscale entanglement in ring polymers under spherical confinement
Creators: name: Tubiana, Luca
name: Orlandini, Enzo
name: Micheletti, Cristian
Publisher: name: arXiv
Year: 2011
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Biological Physics (physics.bio-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The interplay of geometrical and topological entanglement in semiflexible knotted polymer rings confined inside a spherical cavity is investigated using advanced numerical methods. By using stringent and robust algorithms for locating knots, we characterize how the knot length lk depends on the ring contour length, Lc and the radius of the confining sphere, Rc . In the no- and strong- confinement cases we observe weak knot localization and complete knot delocalization, respectively. We show that the complex interplay of lk, Lc and Rc that seamlessly bridges these two limits can be encompassed by a simple scaling argument based on deflection theory. The same argument is used to rationalize the multiscale character of the entanglement that emerges with increasing confinement.
description: 9 pages 9 figures
The decay of turbulence in rotating flows
Creators: name: Teitelbaum, T.
name: Mininni, P. D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We present a parametric space study of the decay of turbulence in rotating flows combining direct numerical simulations, large eddy simulations, and phenomenological theory. Several cases are considered: (1) the effect of varying the characteristic scale of the initial conditions when compared with the size of the box, to mimic "bounded" and "unbounded" flows; (2) the effect of helicity (correlation between the velocity and vorticity); (3) the effect of Rossby and Reynolds numbers; and (4) the effect of anisotropy in the initial conditions. Initial conditions include the Taylor-Green vortex, the Arn'old-Beltrami-Childress flow, and random flows with large-scale energy spectrum proportional to $k^4$. The decay laws obtained in the simulations for the energy, helicity, and enstrophy in each case can be explained with phenomenological arguments that separate the decay of two-dimensional from three-dimensional modes, and that take into account the role of helicity and rotation in slowing down the energy decay. The time evolution of the energy spectrum and development of anisotropies in the simulations are also discussed. Finally, the effect of rotation and helicity in the skewness and kurtosis of the flow is considered.
description: Sections reordered to address comments by referees
Decomposition of operator semigroups on W*-algebras
Creators: name: Bátkai, András
name: Groh, Ulrich
name: Kunszenti-Kovács, Dávid
name: Schreiber, Marco
Publisher: name: arXiv
Year: 2011
Subjects: subject: Operator Algebras (math.OA)
subject: Dynamical Systems (math.DS)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 47D03, 20M20

description: We consider semigroups of operators on a W$^*$-algebra and prove, under appropriate assumptions, the existence of a Jacobs-DeLeeuw-Glicksberg type decomposition. This decomposition splits the algebra into a "stable" and "reversible" part with respect to the semigroup and yields, among others, a structural approach to the Perron-Frobenius spectral theory for completely positive operators on W$^*$-algebras.
description: referee's comments incorporated. To appear in Semigroup Forum
OpenFlexure Microscope 3D Files
Creators: name: Bowman, Richard
name: Stirling, Julian
name: Collins, Joel T.
name: Meng, Qingxin
name: Sanga, Valerian L.
name: Nyakyi, Paul T.
name: Mwakajinga, Grace A
name: McDermott, Samuel
name: Bumke, Kaspar
Publisher: name: Zenodo
Year: 2021

description: Design files for the OpenFlexure Microscope: A 3D-printed, customisable, open-source optical microscope with a precision moveable stage using flexure hinges.
description: RWB gratefully acknowledges support from the Royal Society (URF\R1\180153)
Constraining warm dark matter with cosmic shear power spectra
Creators: name: Markovič, Katarina
name: Bridle, Sarah
name: Slosar, Anže
name: Weller, Jochen
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We investigate potential constraints from cosmic shear on the dark matter particle mass, assuming all dark matter is made up of light thermal relic particles. Given the theoretical uncertainties involved in making cosmological predictions in such warm dark matter scenarios we use analytical fits to linear warm dark matter power spectra and compare (i) the halo model using a mass function evaluated from these linear power spectra and (ii) an analytical fit to the non-linear evolution of the linear power spectra. We optimistically ignore the competing effect of baryons for this work. We find approach (ii) to be conservative compared to approach (i). We evaluate cosmological constraints using these methods, marginalising over four other cosmological parameters. Using the more conservative method we find that a Euclid-like weak lensing survey together with constraints from the Planck cosmic microwave background mission primary anisotropies could achieve a lower limit on the particle mass of 2.5 keV.
description: 26 pages, 9 figures, minor changes to match the version accepted for publication in JCAP
Dislocation-induced superfluidity in a model supersolid
Creators: name: Goswami, D.
name: Dasbiswas, K.
name: Yoo, C. -D.
name: Dorsey, Alan T.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Motivated by recent experiments on the supersolid behavior of $^4$He, we study the effect of an edge dislocation in promoting superfluidity in a Bose crystal. Using Landau theory, we couple the elastic strain field of the dislocation to the superfluid density, and use a linear analysis to show that superfluidity nucleates on the dislocation before occurring in the bulk of the solid. Moving beyond the linear analysis, we develop a systematic perturbation theory in the weakly nonlinear regime, and use this method to integrate out transverse degrees of freedom and derive a one-dimensional Landau equation for the superfluid order parameter. We then extend our analysis to a network of dislocation lines, and derive an XY model for the dislocation network by integrating over fluctuations in the order parameter. Our results show that the ordering temperature for the network has a sensitive dependence on the dislocation density, consistent with numerous experiments that find a clear connection between the sample quality and the supersolid response.
description: 10 pages, 6 figures
The RKKY Coupling between Impurity Spins in Graphene Nanoflakes
Creators: name: Szałowski, Karol
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We calculate the indirect charge carrier mediated Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between magnetic impurities for two selected graphene nanoflakes containing four hexagonal rings in their structure, differing by their geometry. We describe the electronic structure of either charge-neutral or doped nanoflakes using the tight-binding approximation with the Hubbard term, which is treated within the molecular-field approximation. We find pronounced differences in the RKKY coupling energies, dependent on the placement of the pair of magnetic moments in the nanostructure and on the edge form. For an odd total number of electrons in the structure, we predict in some circumstances the existence of ferromagnetic coupling with leading first-order perturbational contribution, while for an even number of charge carriers the usual, second-order mechanism dominates. Therefore, doping of the nanoflake with a single charge carrier is found to be able to change the coupling from an antiferromagnetic to a ferromagnetic one for some geometries.
description: 12 pages, 9 figures
title: Zu diesem Band
Creators: name: Alker-Windbichler, Stefan
name: Köstner-Pemsel, Christina
Publisher: name: Universität Graz
Year: 2021

description: 75 Jahre VÖB. 1946–2021, Hg. v. Alker-Windbichler, Bauer und Köstner-Pemsel, 2021, S. 25–30
Resummation of Threshold, Low- and High-Energy Expansions for Heavy-Quark Correlators
Creators: name: Greynat, D.
name: Peris, S.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: With the help of the Mellin-Barnes transform, we show how to simultaneously resum the expansion of a heavy-quark correlator around q^2=0 (low-energy), q^2= 4 m^2 (threshold, where m is the quark mass) and q^2=-\infty (high-energy) in a systematic way. We exemplify the method for the perturbative vector correlator at O(alpha_s^2) and O(alpha_s^3). We show that the coefficients, Omega(n), of the Taylor expansion of the vacuum polarization function in terms of the conformal variable ωadmit, for large n, an expansion in powers of 1/n (up to logarithms of n) that we can calculate exactly. This large-n expansion has a sign-alternating component given by the logarithms of the OPE, and a fixed-sign component given by the logarithms of the threshold expansion in the external momentum q^2.
description: 27 pages, 8 figures. We fix typos in Eqs. (18), (27), (55) and (56). Results unchanged
Infinite generation of non-cocompact lattices on right-angled buildings
Creators: name: Thomas, Anne
name: Wortman, Kevin
Publisher: name: arXiv
Year: 2010
Subjects: subject: Group Theory (math.GR)
subject: FOS: Mathematics

description: Let Γbe a non-cocompact lattice on a locally finite regular right-angled building X. We prove that if Γhas a strict fundamental domain then Γis not finitely generated. We use the separation properties of subcomplexes of X called tree-walls.
description: 11 pages, one figure. v2: new example and references in the introduction. To appear in Algebr. Geom. Top
Positive and Negative Drag, Dynamic Phases, and Commensurability in Coupled One-Dimensional Channels of Particles with Yukawa Interactions
Creators: name: Reichhardt, C.
name: Bairnsfather, C.
name: Reichhardt, C. J. Olson
Publisher: name: arXiv
Year: 2010
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We introduce a simple model consisting of two or three coupled one-dimensional channels of particles with Yukawa interactions. For the two channel system, when an external drive is applied only to the top or primary channel, we find a transition from locked flow where particles in both channels move together to decoupled flow where the particles in the secondary or undriven channel move at a slower velocity than the particles in the primary or driven channel. Pronounced commensurability effects in the decoupling transition occur when the ratio of the number of particles in the top and bottom channels is varied, and the coupling of the two channels is enhanced when this ratio is an integer or a rational fraction. Near the commensurate fillings, we find additional features in the velocity-force curves caused by the slipping of individual vacancies or incommensurations in the secondary channels. For three coupled channels, when only the top channel is driven we find a remarkably rich variety of distinct dynamic phases, including multiple decoupling and recoupling transitions. These transitions produce pronounced signatures in the velocity response of each channel. We also find regimes where a negative drag effect can be induced in one of the non-driven channels. The particles in this channel move in the opposite direction from the particles in the driven channel due to the mixing of the two different periodic frequencies produced by the discrete motion of the particles in the two other channels. In the two channel system, we also demonstrate a ratchet effect for the particles in the secondary channel when an asymmetric drive is applied to the primary channel. This ratchet effect is similar to that observed in superconducting vortex systems when there is a coupling between two different species of vortices.
description: 20 pages, 25 postscript figures, version published in PRE
Majorana Fermions in Strongly Interacting Helical Liquids
Creators: name: Sela, Eran
name: Altland, Alexander
name: Rosch, Achim
Publisher: name: arXiv
Year: 2011
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Majorana fermions were proposed to occur at edges and interfaces of gapped one-dimensional systems where phases with different topological character meet due to an interplay of spin-orbit coupling, proximity-induced superconductivity and external magnetic fields. Here we investigate the effect of strong particle interactions, and show that the helical liquid offers a mechanism that protects the very existence of Majorana edge states: whereas moderate interactions close the proximity gap which supports the edge states, in helical liquids the gap re-opens due to two-particle processes. However, gapless fermionic excitations occur at spatial proximity to the Majorana states at interfaces and may jeopardize their long term Majorana coherence.
description: 7 pages, 4 figures
Statistical mechanics of homogeneous partly pinned fluid systems
Creators: name: Krakoviack, Vincent
Publisher: name: arXiv
Year: 2010
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The homogeneous partly pinned fluid systems are simple models of a fluid confined in a disordered porous matrix obtained by arresting randomly chosen particles in a one-component bulk fluid or one of the two components of a binary mixture. In this paper, their configurational properties are investigated. It is shown that a peculiar complementarity exists between the mobile and immobile phases, which originates from the fact that the solid is prepared in presence of and in equilibrium with the adsorbed fluid. Simple identities follow, which connect different types of configurational averages, either relative to the fluid-matrix system or to the bulk fluid from which it is prepared. Crucial simplifications result for the computation of important structural quantities, both in computer simulations and in theoretical approaches. Finally, possible applications of the model in the field of dynamics in confinement or in strongly asymmetric mixtures are suggested.
description: 12 pages, 2 figures
Cosmology in nonrelativistic general covariant theory of gravity
Creators: name: Wang, Anzhong
name: Wu, Yumei
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Horava and Melby-Thompson recently proposed a new version of the Horava-Lifshitz theory of gravity, in which the spin-0 graviton is eliminated by introducing a Newtonian pre-potential $ϕ$ and a local U(1) gauge field $A$. In this paper, we first derive the corresponding Hamiltonian, super-momentum constraints, the dynamical equations, and the equations for $ϕ$ and $A$, in the presence of matter fields. Then, we apply the theory to cosmology, and obtain the modified Friedmann equation and the conservation law of energy, in addition to the equations for $ϕ$ and $A$. When the spatial curvature is different from zero, terms behaving like dark radiation and stiff-fluid exist, from which, among other possibilities, bouncing universe can be constructed. We also study linear perturbations of the FRW universe with any given spatial curvature $k$, and derive the most general formulas for scalar perturbations. The vector and tensor perturbations are the same as those recently given by one of the present authors [A. Wang, Phys. Rev. D{\bf 82}, 124063 (2010)] in the setup of Sotiriou, Visser and Weinfurtner. Applying these formulas to the Minkowski background, we have shown explicitly that the scalar and vector perturbations of the metric indeed vanish, and the only remaining modes are the massless spin-2 gravitons.
description: Revtex4, no figures. Gauge freedom was clarified and typos were corrected. Version to appear in Physical Reviews D
Momentum Distribution and Contact of the Unitary Fermi gas
Creators: name: Drut, Joaquín E.
name: Lähde, Timo A.
name: Ten, Timour
Publisher: name: arXiv
Year: 2010
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We calculate the momentum distribution n(k) of the Unitary Fermi Gas using Quantum Monte Carlo calculations at finite temperature T/ε_F as well as in the ground state. At large momenta k/k_F, we find that n(k) falls off as C/k^4, in agreement with the Tan relations. From the asymptotics of n(k), we determine the contact C as a function of T/ε_F and present a comparison with theory. At low T/ε_F, we find that C increases with temperature, and we tentatively identify a maximum around T/ε_F \simeq 0.4. Our calculations are performed on lattices of spatial extent up to N_x = 14 with a particle number per unit volume of \simeq 0.03 - 0.07.
description: 4 pages, 3 figures. Published version
Orbital multicriticality in spin gapped quasi-1D antiferromagnets
Creators: name: Sela, Eran
name: Pereira, R. G.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Motivated by the quasi-1D antiferromagnet CaV$_2$O$_4$, we explore spin-orbital systems in which the spin modes are gapped but orbitals are near a macroscopically degenerate classical transition. Within a simplified model we show that gapless orbital liquid phases possessing power-law correlations may occur without the strict condition of a continuous orbital symmetry. For the model proposed for CaV$_2$O$_4$, we find that an orbital phase with coexisting order parameters emerges from a multicritical point. The effective orbital model consists of zigzag-coupled transverse field Ising chains. The corresponding global phase diagram is constructed using field theory methods and analyzed near the multicritical point with the aid of an exact solution of a zigzag XXZ model.
description: 9 pages
Samara no. 13 [Spanish].
Creators: name: Millennium Seed Bank Project
Publisher: name: Royal Botanic Gardens, Kew
Year: 2007
Subjects: Lebanon
Plant conservation
Namibia
Seed collection
Seed banks
Botswana
Chile
Ex situ conservation
Millennium Seed Bank Project
Malawi
Kenya
Plant re-introductions
Global Strategy for Plant Conservation (GSPC)
South Africa

description: IF = none.
description: Ardingly, West Sussex, UK
Realtime magnetic field sensing and imaging using a single spin in diamond
Creators: name: Schoenfeld, Rolf Simon
name: Harneit, Wolfgang
Publisher: name: arXiv
Year: 2010
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The Zeeman splitting of a localized single spin can be used to construct a magnetometer allowing high precision measurements of magnetic fields with almost atomic spatial resolution. While sub-μT sensitivity can in principle be obtained using pulsed techniques and long measurement times, a fast and easy-to-use method without laborious data post-processing is desirable for a scanning-probe approach with high spatial resolution. In order to measure the resonance frequency in realtime, we applied a field-frequency lock to the continuous wave ODMR signal of a single electron spin in a nanodiamond. In our experiment, we achieved a sampling rate of up to 100 readings per second with a sensitivity of 6 μT/$\sqrt{Hz}$. Using this method we have imaged the microscopic field distribution around a magnetic wire. Images with \sim 30 μT resolution and 4096 sub-micron sized pixels were acquired in 10 minutes. By measuring the field response of multiple spins on the same object we were able to partly reconstruct the orientation of the field.
title: o-bib. Das offene Bibliotheksjournal / Herausgeber VDB, Bd. 8 Nr. 3 (2021)
title: o-bib. Das offene Bibliotheksjournal, Ausgabe 3/2021
titleType: AlternativeTitle
Creators: name: O-Bib. Das Offene Bibliotheksjournal / Herausgeber VDB
Publisher: name: o-bib. Das offene Bibliotheksjournal / Herausgeber VDB
Year: 2021

description: Kommission für forschungsnahe Dienste Dr. Antonius Jammers (2. Februar 1937 – 1. Dezember 2020) ...1-2 Hör mal – Arbeiten mit Hörmedien im Institut für angewandte Kindermedienforschung ...1-8 Rezension zu: Historisches Erbe und zeitgemäße Informationsinfrastrukturen : Bibliotheken am Anfang des 21. Jahrhunderts : Festschrift für Axel Halle / Matthias Schulze (Hrsg.)...1-5 Aus der Deutschen Forschungsgemeinschaft...1-4 Bericht aus der 80. Sitzung der Arbeitsgemeinschaft der Verbundsysteme am 15. April 2021...1-7 Offene Lizenzen für Forschungsdaten...1-22 Rezension zu: Mythos Lesen : Buchkultur und Geisteswissenschaften im Informationszeitalter / Klaus Benesch...1-3 VDB-Kommissionen – Mitglieder der neuen Amtszeit 2021 – 2024 ...1-2 Danke an Susanne Kandler, Elke Reher, Matthias Harbeck und Wolfgang Stille für erfolgreiche Kommissionsarbeit...1-2 Lydia Koglin und Ulrike Scholle beenden erfolgreiche Vorstandstätigkeit...1 Rezension zu: Libraries and their architecture in the 21st century / edited by Ines Miersch-Süß...1-3 Zur Erinnerung an Dr. Hermann Leskien...1-2 Von NEBIS zu SLSP...1-15 Bibliotheken in der Open Access-Transformation...1-5
Some general properties of unified entropies
Creators: name: Rastegin, Alexey E.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Basic properties of the unified entropies are examined. The consideration is mainly restricted to the finite-dimensional quantum case. Bounds in terms of ensembles of quantum states are given. Both the continuity in Fannes' sense and stability in Lesche's sense are shown for wide ranges of parameters. In particular, uniform estimates are obtained for the quantum Rényi entropies. Stability properties in the thermodynamic limit are discussed as well. It is shown that the unified entropies enjoy both the subadditivity and triangle inequality for a certain range of parameters. Non-decreasing of all the unified entropies under projective measurement is proved.
description: 11 pages, no figures. Minor grammatical changes are made. To appear in J. Stat. Phys
title: VÖB 75 Jahre – Anmerkungen – ein historischer Exkurs - Statement
Creators: name: Kubalek, Peter
Publisher: name: Universität Graz
Year: 2021

description: 75 Jahre VÖB. 1946–2021, Hg. v. Alker-Windbichler, Bauer und Köstner-Pemsel, 2021, S. 33–35
Magneto-optical Kerr Effect Studies of Square Artificial Spin Ice
Creators: name: Kohli, K. K.
name: Balk, Andrew L.
name: Li, Jie
name: Zhang, Sheng
name: Gilbert, Ian
name: Lammert, Paul E.
name: Crespi, Vincent H.
name: Schiffer, Peter
name: Samarth, Nitin
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report a magneto-optical Kerr effect study of the collective magnetic response of artificial square spin ice, a lithographically-defined array of single-domain ferromagnetic islands. We find that the anisotropic inter-island interactions lead to a non-monotonic angular dependence of the array coercive field. Comparisons with micromagnetic simulations indicate that the two perpendicular sublattices exhibit distinct responses to island edge roughness, which clearly influence the magnetization reversal process. Furthermore, such comparisons demonstrate that disorder associated with roughness in the island edges plays a hitherto unrecognized but essential role in the collective behavior of these systems.
description: Physical Review B, Rapid Communications (in press)
Forord 2
Creators: name: Bangshaab, Jette
Publisher: name: UCN Perspektiv
Year: 2021

description: I det følgende er der en kort introduktion til centrale temaer og omdrejningspunkter for de 11 artikler, som du kan se frem til at læse i denne udgivelse af UCN Perspektiv. Artiklerne er alle produkter og konkrete resultater af den opbygning af forskning og udvikling på UCN’s teknologiuddannelser, som er beskrevet af uddannelsesleder Jens Christian Kløve Hansen i indledningen.
description: UCN Perspektiv, Nr. 9 (2021): Teknologi
Forord 1
Creators: name: Kløve, Jens Christian Hansen
Publisher: name: UCN Perspektiv
Year: 2021

description: Denne udgave af UCN Perspektiv indeholder en række af artikler forfattet af medarbejdere, der har arbejdet med udgangspunkt i det forskningsfokus, der blev formuleret for UCN’s teknologiuddannelser i 2017. Denne indledning er en kort indflyvning til den proces, der har dannet rammen for, at der i denne udgave foreligger en række artikler, der spænder bredt fagligt.
description: UCN Perspektiv, Nr. 9 (2021): Teknologi
On the Rate of Convergence of Weak Euler Approximation for Nondegenerate SDEs Driven by Levy Processes
Creators: name: Mikulevicius, R.
name: Zhang, C.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60J75 (primary), 60J60, 60H30, 45K05, 35S10

description: The paper studies the rate of convergence of the weak Euler approximation for solutions to SDEs driven by Levy processes, with Hoelder-continuous coefficients. It investigates the dependence of the rate on the regularity of coefficients and driving processes. The equation considered has a non-degenerate main part driven by a spherically-symmetric stable process.
Skal vi lære i byggeprojekterne, skal vi starte med tillid!
Creators: name: Beck, Frederikke
name: Andersen, Michael
name: Falk Trudslev, Søren
Publisher: name: UCN Perspektiv
Year: 2021

description: Byggebranchen skal være bæredygtig. Med bæredygtigheden kommer nye aktører og nye materialer, som kræver nye arbejdsprocesser. Udviklingen af nye arbejdsprocesser kan foregå i fællesskab i byggeprojekterne via samskabelse mellem de forskellige aktører. En samskabelsesproces, som faciliteres med et fokus på ekspansive læringsmuligheder, hvor tillid har en uafklaret betydning. Formål: Hvilke muligheder og perspektiver omhandlende tillid kan anvendes og bidrage til faciliteringen af samskabelsesprocessen i et inter-organisatorisk samarbejde? Metode: Tillid undersøges ud fra en teoretisk analytisk tilgang, hvor tre artikler er udvalgt ud fra deres kontekst. Artiklerne analyseres og diskuteres i forhold til opbyggelsen af tillid i samskabelsesprocessen. Konklusion: Resultaterne indikerer, at faciliteringen i samskabelsen med fokus på tillid bør have to afsæt; rammesætningen og samskabelsesprocessen, hvor små og store risikofyldte handlinger kan virke tillidsopbyggende. Under samskabelsen bør facilitatoren være opmærksom på aktørernes åbenhed over for hinanden og nye input samt på aktørernes indbyrdes omsorg, bekymring, ærlighed og forståelse, hvilket kan medvirke til, at facilitatoren kan skabe ekspansive læringsmuligheder.
description: UCN Perspektiv, Nr. 9 (2021): Teknologi
Unscreening the Gaugino Mass with Chiral Messengers
Creators: name: Argurio, Riccardo
name: Bertolini, Matteo
name: Ferretti, Gabriele
name: Mariotti, Alberto
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Gaugino screening, the absence of next-to-leading order corrections to gaugino masses, is a generic feature of gauge mediation models of supersymmetry breaking. We show that in a specific class of models, known as semi-direct gauge mediation, it is possible to avoid gaugino screening by allowing for a chiral messenger sector. Messengers then acquire a mass at some scale, for instance by higgsing or by some auxiliary strong coupling dynamics. We implement this idea in a simple model which we work out explicitly.
description: 17 pages, 3 figures. Minor clarifications added in Section 2, version to appear in JHEP
Modeling the time-resolved quasi-periodic oscillations in AGNs
Creators: name: Das, Tapas Kumar
name: Czerny, Bozena
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Observation of the bright Seyfert 1 galaxy RE J1034+396 is believed to demonstrate a drift of the central period of the Quasi Periodic Oscillation (QPO) linearly correlated with the temporary X-ray luminosity. We show, using a specific scenario of the oscillation mechanism in black hole accretion disc, that modeling such correlated trends puts very strong constraints on the nature of this oscillation and the characteristic features of the hot flow in Active Galactic Nuclei (AGN). In our model, QPO oscillations are due to the oscillations of the shock formed in the low angular momentum hot accretion flow, and the variation of the shock location corresponds to the observed changes in the QPO period and the X-ray flux. In this scenario, change in the shock location caused by perturbation of the flow angular momentum is compatible with the trends observed in RE J1034+396, whereas the perturbation of the specific flow energy results in too strong flux response to the change of the oscillation period. Using a complete general relativistic framework to study the accretion flow in the Kerr metric, we discuss the role of the black hole spin in the period drift. Future missions are expected to bring more active galaxies with time-resolved quasi-periodic oscillations so similar quantitative study for other QPO scenarios will be necessary.
description: Final version accepted for publication in MNRAS. Several modifications made. Eight pages. Six colour figures
Symmetry-breaking lattice distortion in Sr_3Ru_2O_7
Creators: name: Stingl, C.
name: Perry, R. S.
name: Maeno, Y.
name: Gegenwart, P.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The electronic nematic phase of Sr$_3$Ru$_2$O$_7$ is investigated by high-resolution in-plane thermal expansion measurements in magnetic fields close to 8 T applied at various angles $Θ$ off the c-axis. At $Θ<10^\circ$ we observe a very small ($10^{-7}$) lattice distortion which breaks the four-fold in-plane symmetry, resulting in nematic domains with interchanged $a$- and b-axis. At $Θ\gtrsim 10^\circ$ the domains are almost fully aligned and thermal expansion indicates an area-preserving lattice distortion of order $2\times 10^{-6}$ which is likely related to orbital ordering. Since the system is located in the immediate vicinity to a metamagnetic quantum critical end point, the results represent the first observation of a structural relaxation driven by quantum criticality.
description: 4 pages, 5 figures, PRL accepted
Simple groups admit Beauville structures
Creators: name: Guralnick, Robert
name: Malle, Gunter
Publisher: name: arXiv
Year: 2010
Subjects: subject: Group Theory (math.GR)
subject: Algebraic Geometry (math.AG)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: Primary 20D06, Secondary 14H30, 14J10, 20G15, 20C33

description: We answer a conjecture of Bauer, Catanese and Grunewald showing that all finite simple groups other than the alternating group of degree 5 admit unmixed Beauville structures. We also consider an analog of the result for simple algebraic groups which depends on some upper bounds for character values of regular semisimple elements in finite groups of Lie type and obtain definitive results about the variety of triples in semisimple regular classes with product 1. Finally, we prove that any finite simple group contains two conjugacy classes C,D such that any pair of elements in C x D generates the group.
description: 30 pages, in the second version, some results are improved and in particular we prove an irreducibility for a certain variety
Skridttæller til kørestolsbruger
Creators: name: Belle, Gianna
name: Pedersen, Christina Koch
name: Støy, Ole Bjerregaard
name: Thomsen, Henning
name: Vutborg, Steffen
Publisher: name: UCN Perspektiv
Year: 2021

description: Aktivitetsmålere har været populære i det sidste årti, men de er ikke tilpasset kørestolsbrugere og giver derfor ikke pålidelige data angående kørestolsbrugeres kalorieforbrug. En aktivitetsmåler skræddersyet til kørestolsbrugere vil øge motivationen til fysisk aktivitet og forebygge livsstils­sygdomme. Vores mål er at undersøge, hvordan sensorer placeret på kørestolen kan bruges i udviklingen af en teknisk platform, herunder en aktivitetsmåler til kørestolsbrugere. Vi har udviklet en prototype, hvor drivhjulene på en kørestol til kørestolsbasket er udstyret med vejeceller, inertimåleenheder og mikrokontrollere. Mikrokontrollere indsamler data fra sensorer og overfører dem via Bluetooth til en mobilenhed, som bruger en app til at analysere og vise data om aktiviteter. Med denne opsætning er det muligt at tælle de relevante antal tag, som en kørestolsbruger foretager, og at få andre interessante måledata til videreudvikling af vores aktivitetsmåler.
description: UCN Perspektiv, Nr. 9 (2021): Teknologi
Nuclear reaction rates and the primordial nucleosynthesis
Creators: name: Mishra, Abhishek
name: Basu, D. N.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Theory (nucl-th)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The theoretical predictions of the primordial abundances of elements in the big-bang nucleosynthesis (BBN) are dominated by uncertainties in the input nuclear reaction rates. We investigate the effect of modifying these reaction rates on light element abundance yields in BBN by replacing the thirty-five reaction rates out of the existing eighty-eight. We have studied these yields as functions of evolution time or temperature. We find that using these new reaction rates results in only a little increase in helium mass fraction over that obtained previously in BBN calculations. This allows insights into the role of the nuclear reaction rates in the setting of the neutron-to-proton ratio during the BBN epoch. We observe that even with considerable nuclear physics uncertainties, most of these nuclear reactions have minimal effect on the standard BBN abundance yields of $^6$Li and $^7$Li.
description: 6 pages including 5 figures and 2 tables; Accepted for presentation at DAE Symposium on Nuclear Physics, December 26-30, 2011, Department of Nuclear Physics, Andhra University, Visakhapatnam, A.P., India
The Parameterised Post-Newtonian Limit of Bimetric Theories of Gravity
Creators: name: Clifton, Timothy
name: Bañados, Máximo
name: Skordis, Constantinos
Publisher: name: arXiv
Year: 2010
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We consider the post-Newtonian limit of a general class of bimetric theories of gravity, in which both metrics are dynamical. The established parameterised post-Newtonian approach is followed as closely as possible, although new potentials are found that do not exist within the standard frame-work. It is found that these theories can evade solar system tests of post-Newtonian gravity remarkably well. We show that perturbations about Minkowski space in these theories contain both massless and massive degrees of freedom, and that in general there are two different types of massive mode, each with a different mass parameter. If both of these masses are sufficiently large then the predictions of the most general class of theories we consider are indistinguishable from those of general relativity, up to post-Newtonian order in a weak field, low velocity expansion. In the limit that the massive modes become massless, we find that these general theories do not exhibit a van Dam-Veltman-Zakharov-like discontinuity in their gamma parameter, although there are discontinuities in other post-Newtonian parameters as the massless limit is approached. This smooth behaviour in gamma is due to the discontinuities from each of the two different massive modes cancelling each other out. Such cancellations cannot occur in special cases with only one massive mode, such as the Isham-Salam-Strathdee theory.
description: 36 pages
Forankring af viden via praktik
Creators: name: Antonsen, Mikkel Gravgaard
name: Borregaard, Thorbjørn
name: Christiansen, Lasse
name: Rosenkilde, Bent
Publisher: name: UCN Perspektiv
Year: 2021

description: Virtuelle prototyper, i form af 3D-CAD-modeller, indgår i mange sammenhænge, blandt andet som et redskab til design og analyse af produkter, eksempelvis komponenter, maskiner, tekstiler og møbler. Aftagerne til Professionshøjskolen UCN’s uddannelser inden for fremstillingsindustrien bruger kun virtuelle prototyper i begrænset omfang. Derfor har underviserne ved disse uddannelser tidligere forsket i, hvad barriererne er for brugen af virtuelle prototyper. Den genererede forskningsviden er blandt andet udbredt via studerende i praktik­ophold ved små og mellemstore virksomheder. Denne praktikantbaserede udbredelsesform har ikke samme skalerbarhed som mere almene netværks- og publikationskanaler. Den giver derimod en dybere forankring i den enkelte virksomhed, og den styrker således relationen mellem de studerende, videninstitutionerne og virksomhederne, der bidrager som praktikværter. Metodisk tager denne artikel udgangspunkt i empiri fra tre produktionsteknologstuderendes praktikophold. Data er indsamlet via semistrukturerede interviews og efterfølgende analyseret gennem en clusteranalyse (Gioia-metodikken). Formålet med denne artikel er at undersøge, i hvilket omfang og på hvilke måder de studerende via praktikophold kan bruges som medie til at udbrede forskningsbaseret viden til små og mellemstore virksomheder. Artiklen konkluderer, at studerende og praktikvirksomhederne deler læring og nye tekniske indsigter. Slutteligt drages perspektiver til andre brancher, ligesom betydningen for uddannelse og industri diskuteres.
description: UCN Perspektiv, Nr. 9 (2021): Teknologi
Generating Function Formula of Heat Transfer in Harmonic Networks
Creators: name: Saito, Keiji
name: Dhar, Abhishek
Publisher: name: arXiv
Year: 2010
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We consider heat transfer across an arbitrary harmonic network connected to two heat baths at different temperatures. The network has $N$ positional degrees of freedom, of which $N_L$ are connected to a bath at temperature $T_L$ and $N_R$ are connected to a bath at temperature $T_R$. We derive an exact formula for the cumulant generating function for heat transfer between the two baths. The formula is valid even for $N_L \ne N_R$ and satisfies the Gallavotti-Cohen fluctuation symmetry. Since harmonic crystals in three dimensions are known to exhibit different regimes of transport such as ballistic, anomalous and diffusive, our result implies validity of the fluctuation theorem in all regimes. Our exact formula provides a powerful tool to study other properties of nonequilibrium current fluctuations.
description: 5 pages, 1 figure
Optimering af produktion
Creators: name: Hvarregaard, Brian
name: Nordbjerg, Finn E.
name: Iftikhar, Nadeem
Publisher: name: UCN Perspektiv
Year: 2021

description: Baggrunden for denne artikel er arbejdet med produktionsvirksomheder, og hvordan en lille eller mellemstor virksomhed kan opsamle data fra egen produktion og analysere dette data med det formål at optimere den fremtidige produktion. Dette har et stort potentiale for små og mellemstore virksomheder i Danmark. Denne artikel beskriver et projekt, hvor der i samarbejde med en lokal produktionsvirksomhed er opsamlet data på en effektiv og struktureret måde samt benyttet maskinlæring til at analysere data for at forudsige driftsstop. Uventede driftsstop kan være omkostningstunge og forsinke den planlagte produktion. Metoden til at arbejde med dette benytter aktionsforskning og elementer fra Design Thinking. Der udvikles løsninger i fællesskab, som prøves af i praksis, og der læres af disse løsninger. Den udviklede softwareplatform er i konstant forandring, krav og ønsker fra virksomheden generaliseres og benyttes som en generel løsningsmodel for andre SMV’er i fremstillingssektoren. I samarbejde med en lokal SMV er der udviklet en prototype på et system med en fleksibel, robust arkitektur. Systemet kan lagre store datamængder (big data) og fremvise analyseresultater near real-time. Endvidere beskrives en arbejdsproces, som er tilpasset SMV’ens kompetenceniveau og organisation. Processen skal støtte SMV’er, som vil i gang med at udnytte deres produktionsdata.
description: UCN Perspektiv, Nr. 9 (2021): Teknologi
Internet of Things i Sundhedsbrug
Creators: name: Thomsen, Henning
name: Kongshøj, Simon
name: Nielsen, Ib Helmer
name: Hvarregaard, Henrik Munk
name: Trosborg, Per
Publisher: name: UCN Perspektiv
Year: 2021

description: Internet of Things (IoT) opnår stigende udbredelse i samfundet, herunder sundhedssektoren. Desværre er informationssikkerheden i disse enheder ofte mangelfuld. Der undersøges, om datatrafikken i et sundheds-IoT-system er forsvarligt sikret. IoT-systemet, som undersøges, er udlånt af en virksomhed og er et system til lokationssporing af demente personer. Sikkerhedsundersøgelsen bliver lavet med udgangspunkt i begreberne confidentiality, integrity og availability. Til at undersøge sikkerheden samt underbygge de fundne sårbarheder udarbejdes en litteraturundersøgelse, hvor informationen søges frem i udbredte tidsskrifter. Desuden laves en forsøgsopstilling til undersøgelsen. Ud fra undersøgelserne kan det ses, at der primært er udfordringer med sikkerheden ift. kodeord samt med kommunikationsprotokoller. Undersøgelserne resulterer i en tjekliste, hvor sårbarheder er listet, samt henvisning til begreberne C, I og A (confidentiality, integrity og availability), og der gives anbefalinger til håndtering af sårbarhederne. Denne tjekliste er tiltænkt IT-ansvarlige i kommuner, på plejehjem mv., som kan bruge listen ved indkøb af sundheds-IoT-udstyr.
description: UCN Perspektiv, Nr. 9 (2021): Teknologi
Impacts of biochar application to a Douglas-fir forest soil on greenhouse gas fluxes and water quality
Creators: name: Hawthorne, Iain
Publisher: name: University of British Columbia
Year: 2017

description: Forest management for carbon sequestration is a valuable tool to combat rising greenhouse gas (GHG) concentrations in the Earth’s atmosphere. This thesis examined the use of biochar, a product of the thermal decomposition of waste organic matter in a reduced oxygen environment (i.e. pyrolysis) that is applied to soil, as an option for increasing carbon sequestration in a Coastal Douglas-fir forest soil in British Columbia when applied with and without urea fertilizer at 200 kg N ha-¹. Biochar produced from Douglas-fir forestry slash materials was used in this study to address this from a systems-based perspective. A soil incubation study showed that biochar application at high rates (10% oven dry soil basis) significantly increased CO₂ and N₂O emissions when applied without fertilizer and at both low (1%) and high rates (10%) decreased CH₄ consumption without fertilization. In terms of carbon dioxide equivalent emissions (CO₂e), it was shown that CO₂ accounted for >98% from all treatments. In a field study, GHG fluxes were measured after application of 5 t ha-¹ of biochar to a Douglas-fir forest soil in the first year followed by urea-N fertilization in the second year. The results showed that 5 t ha-¹ of biochar had little effect on GHG fluxes and their total CO₂e fluxes. Applying biochar prior to fertilizer application following industry-standard practices did not significantly change treatment CO₂e fluxes. It was concluded that low rates of biochar application to this forest soil would improve soil C sequestration with or without fertilization. In the field and laboratory experiments, soil pore water was extracted and analyzed for C and N concentrations and dissolved organic carbon using spectral indices. The results showed that low biochar application rates could be beneficial for both increasing C-sequestration and N-retention. Changes in spectral indices measured in the laboratory suggested that alterations in the dissolved organic matter pool could lead to changes in GHG emissions due to changing substrate supply for microbes as application rates increased. There is a recognized need for further studies prior to large-scale industrial applications; however, as result of this work it is possible to provide recommendations for large-scale pilot studies.