cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Vertex Sparsifiers: New Results from Old Techniques
Creators: name: Englert, Matthias
name: Gupta, Anupam
name: Krauthgamer, Robert
name: Raecke, Harald
name: Talgam, Inbal
name: Talwar, Kunal
Publisher: name: arXiv
Year: 2010
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Computer and information sciences

description: Given a capacitated graph $G = (V,E)$ and a set of terminals $K \subseteq V$, how should we produce a graph $H$ only on the terminals $K$ so that every (multicommodity) flow between the terminals in $G$ could be supported in $H$ with low congestion, and vice versa? (Such a graph $H$ is called a flow-sparsifier for $G$.) What if we want $H$ to be a "simple" graph? What if we allow $H$ to be a convex combination of simple graphs? Improving on results of Moitra [FOCS 2009] and Leighton and Moitra [STOC 2010], we give efficient algorithms for constructing: (a) a flow-sparsifier $H$ that maintains congestion up to a factor of $O(\log k/\log \log k)$, where $k = |K|$, (b) a convex combination of trees over the terminals $K$ that maintains congestion up to a factor of $O(\log k)$, and (c) for a planar graph $G$, a convex combination of planar graphs that maintains congestion up to a constant factor. This requires us to give a new algorithm for the 0-extension problem, the first one in which the preimages of each terminal are connected in $G$. Moreover, this result extends to minor-closed families of graphs. Our improved bounds immediately imply improved approximation guarantees for several terminal-based cut and ordering problems.
description: An extended abstract appears in the 13th International Workshop on Approximation Algorithms for Combinatorial Optimization Problems (APPROX), 2010. Final version to appear in SIAM J. Computing
High-field termination of a Cooper-pair insulator
Creators: name: Sacépé, B.
name: Seidemann, J.
name: Ovadia, M.
name: Tamir, I.
name: Shahar, D.
name: Chapelier, C.
name: Strunk, Christoph
name: Piot, B. A.
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: 530 Physik

description: We conducted a systematic study of the disorder dependence of the termination of superconductivity, at high magnetic fields (B), of amorphous indium oxide films. Our lower disorder films show conventional behavior where superconductivity is terminated with a transition to a metallic state at a well-defined critical field, Bc2. Our higher-disorder samples undergo a B-induced transition into a strongly insulating state, which terminates at higher B's forming an insulating peak. We demonstrate that the B terminating this peak coincides with Bc2 of the lower disorder samples. Additionally, we show that, beyond this field, these samples enter a different insulating state in which the magnetic field dependence of the resistance is weak. These results provide crucial evidence for the importance of Cooper-pairing in the insulating peak regime.
Current-controllable planar S-(S/F)-S Josephson junction
Creators: name: Vavra, Ondrej
name: Pfaff, Wolfgang
name: Monaco, R.
name: Aprili, M.
name: Strunk, Christoph
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: 530 Physik

description: We report on the experimental realization of a current-controllable lateral S-(S/F)-S Josephson junction based on the inverse proximity effect in the superconductor-ferromagnet bilayer (S/F). The dependence of the critical current on the magnetic field I c (B) shows a Fresenel-like pattern, which could qualitatively be understood with the theory of Josephson junctions in a magnetic field gradient. The amplitude and the period of the I c (B) pattern can be controlled by spin-polarized quasiparticles injection into the weak link. The period change suggests controllability of effective area of the Josephson junction. Furthermore, a temperature-induced transition from a weak-link behavior to a strong coupling between the superconducting banks is also observed in these lateral Josephson junctions.
Linear-scaling explicitly correlated treatment of solids: Periodic local MP2-F12 method
Creators: name: Usvyat, Denis
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: 540 Chemie

description: Theory and implementation of the periodic local MP2-F12 method in the 3*A fixed-amplitude ansatz is presented. The method is formulated in the direct space, employing local representation for the occupied, virtual, and auxiliary orbitals in the form of Wannier functions (WFs), projected atomic orbitals (PAOs), and atom-centered Gaussian-type orbitals, respectively. Local approximations are introduced, restricting the list of the explicitly correlated pairs, as well as occupied, virtual, and auxiliary spaces in the strong orthogonality projector to the pair-specific domains on the basis of spatial proximity of respective orbitals. The 4-index two-electron integrals appearing in the formalism are approximated via the direct-space density fitting technique. In this procedure, the fitting orbital spaces are also restricted to local fit-domains surrounding the fitted densities. The formulation of the method and its implementation exploits the translational symmetry and the site-group symmetries of the WFs. Test calculations are performed on LiH crystal. The results show that the periodic LMP2-F12 method substantially accelerates basis set convergence of the total correlation energy, and even more so the correlation energy differences. The resulting energies are quite insensitive to the resolution-of-the-identity domain sizes and the quality of the auxiliary basis sets. The convergence with the orbital domain size is somewhat slower, but still acceptable. Moreover, inclusion of slightly more diffuse functions, than those usually used in the periodic calculations, improves the convergence of the LMP2-F12 correlation energy with respect to both the size of the PAO-domains and the quality of the orbital basis set. At the same time, the essentially diffuse atomic orbitals from standard molecular basis sets, commonly utilized in molecular MP2-F12 calculations, but problematic in the periodic context, are not necessary for LMP2-F12 treatment of crystals.
A multiscale modeling study of loss processes in block-copolymer-based solar cell nanodevices
Creators: name: Donets, Sergii
name: Pershin, Anton
name: Christlmaier, Martin J. A.
name: Baeurle, Stephan A.
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: 540 Chemie

description: Flexible photovoltaic devices possess promising perspectives in opto-electronic technologies, where high mobility and/or large-scale applicability are important. However, their usefulness in such applications is currently still limited due to the low level of optimization of their performance and durability. For the improvement of these properties, a better understanding and control of small-scale annihilation phenomena involved in the photovoltaic process, such as exciton loss and charge carrier loss, is necessary, which typically implicates multiple length- and time-scales. Here, we study the causes for their occurrence on the example of nanostructured diblock- and triblock-copolymer systems by making use of a novel solar-cell simulation algorithm and explore new routes to optimize their photovoltaic properties. A particular focus is set on the investigation of exciton and charge carrier loss phenomena and their dependence on the inter-monomeric interaction strength, chain architecture, and external mechanical loading. Our simulation results reveal that in the regime from low up to intermediate χ-parameters an increasing number of continuous percolation paths is created. In this parameter range, the internal quantum efficiency (IQE) increases up to a maximum, characterized by a minimum in the number of charge losses due to charge recombination. In the regime of high χ-parameters both block-copolymer systems form nanostructures with a large number of bottlenecks and dead ends. These lead to a large number of charge losses due to charge recombination, charge trapping, and a deteriorated exciton dissociation, resulting in a significant drop in the IQE. Moreover, we find that the photovoltaic performance of the triblock-copolymer material decreases with increasing mechanical loading, caused by a growing number of charge losses due to charge recombination and charge accumulation. Finally, we demonstrate that the process of charge trapping in defects can be reversed by changing the polarity of the electrodes, which confers these materials the ability to be used as charge storage media.
Dynamic nuclear spin polarization in an all-semiconductor spin injection device with (Ga,Mn)As/n-GaAs spin Esaki diode
Creators: name: Shiogai, Junichi
name: Ciorga, Mariusz
name: Utz, Martin
name: Schuh, Dieter
name: Arakawa, T.
name: Kohda, M.
name: Kobayashi, K.
name: Ono, T.
name: Wegscheider, W.
name: Weiss, Dieter
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: 530 Physik

description: We investigate the dynamic nuclear spinpolarization in an n-GaAs lateral channel induced by electrical spin injection from a (Ga,Mn)As/n-GaAs spin Esaki diode. Signatures of nuclear spinpolarization are studied in both three-terminal and non-local voltage signals, where a strong electron spin depolarization feature is observed close to zero magnetic field. This is due to the large nuclear field induced in the channel through hyperfine interaction between injected electron spins and localized nuclear spins. We study the time evolution of the dynamic nuclear spinpolarization and evaluate polarization and relaxation times of nuclear spins in the channel.
Microsolvation in superfluid helium droplets studied by the electronic spectra of six porphyrin derivatives and one chlorine compound
Creators: name: Riechers, Alexander
name: Pentlehner, D.
name: Slenczka, Alkwin
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: 540 Chemie

description: After almost two decades of high resolution molecular spectroscopy in superfluid helium droplets, the understanding of microsolvation is still the subject of intense experimental and theoretical research. According to the published spectroscopic work including microwave, infrared, and electronic spectroscopy, the latter appears to be particularly promising to study microsolvation because of the appearance of pure molecular transitions and spectrally separated phonon wings. Instead of studying the very details of the influence of the helium environment for one particular dopant molecule as previously done for phthalocyanine, the present study compares electronic spectra of a series of non-polar porphyrin derivatives when doped into helium droplets consisting of 104–105 helium atoms. Thereby, we focus on the helium-induced fine structure, as revealed most clearly at the corresponding electronic origin. The interpretation and the assignment of particular features obtained in the fluorescence excitation spectra are based on additional investigations of dispersed emission spectra and of the saturation behavior. Besides many dopant-specific results, the experimental study provides strong evidence for a particular triple peak feature representing the characteristic signature of helium solvation for all seven related dopant species.
Scanning transmission electron microscopy strain measurement from millisecond frames of a direct electron charge coupled device
Creators: name: Müller, Knut
name: Ryll, Henning
name: Ordavo, Ivan
name: Ihle, Sebastian
name: Strüder, Lothar
name: Volz, Kerstin
name: Zweck, Josef
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: 530 Physik

description: A high-speed direct electron detection system is introduced to the field of transmission electron microscopy and applied to strain measurements in semiconductor nanostructures. In particular, a focused electron probe with a diameter of 0.5 nm was scanned over a fourfold quantum layer stack with alternating compressive and tensile strain and diffracted discs have been recorded on a scintillator-free direct electron detector with a frame time of 1 ms. We show that the applied algorithms can accurately detect Bragg beam positions despite a significant point spread each 300 kV electron causes during detection on the scintillator-free camera. For millisecond exposures, we find that strain can be measured with a precision of 1.3 × 10−3, enabling, e.g., strain mapping in a 100×100 nm2 region with 0.5 nm resolution in 40 s.
A frozen super-Earth orbiting a star at the bottom of the Main Sequence
Creators: name: Kubas, D.
name: Beaulieu, J. P.
name: Bennett, D. P.
name: Cassan, A.
name: Cole, A.
name: Lunine, J.
name: Marquette, J. B.
name: Dong, S.
name: Gould, A.
name: Sumi, T.
name: Batista, V.
name: Fouque, P.
name: Brillant, S.
name: Dieters, S.
name: Coutures, C.
name: Greenhill, J.
name: Bond, I.
name: Nagayama, T.
name: Udalski, A.
name: Pompei, E.
name: Nuernberger, D. E. A.
name: Bouquin, J. B. Le
Publisher: name: arXiv
Year: 2010
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We observed the microlensing event MOA-2007-BLG-192 at high angular resolution in JHKs with the NACO adaptive optics system on the VLT while the object was still amplified by a factor 1.23 and then at baseline 18 months later. We analyzed and calibrated the NACO photometry in the standard 2MASS system in order to accurately constrain the source and the lens star fluxes. We detect light from the host star of MOA-2007-BLG-192Lb, which significantly reduces the uncertainties in its char- acteristics as compared to earlier analyses. We find that MOA-2007-BLG-192L is most likely a very low mass late type M-dwarf (0.084 [+0.015] [-0.012] M\odot) at a distance of 660 [+100] [-70] pc orbited by a 3.2 [+5.2] [-1.8] M\oplus super-Earth at 0.66 [+0.51] [-0.22] AU. We then discuss the properties of this cold planetary system.
description: published version A&A 540, A78 (2012) A&A, 10 pages, 7 Figures
A polynomial invariant and duality for triangulations
Creators: name: Krushkal, Vyacheslav
name: Renardy, David
Publisher: name: arXiv
Year: 2010
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: The Tutte polynomial is a classical invariant, important in combinatorics and statistical mechanics. An essential feature of the Tutte polynomial is the duality for planar graphs G, $T_G(X,Y)\; =\; {T}_{G^*}(Y,X)$ where $G^*$ denotes the dual graph. We examine this property from the perspective of manifold topology, formulating polynomial invariants for higher-dimensional simplicial complexes. Polynomial duality for triangulations of a sphere follows as a consequence of Alexander duality. The main goal of this paper is to introduce and begin the study of a more general 4-variable polynomial for triangulations and handle decompositions of orientable manifolds. Polynomial duality in this case is a consequence of Poincare duality on manifolds. In dimension 2 these invariants specialize to the well-known polynomial invariants of ribbon graphs defined by B. Bollobas and O. Riordan. Examples and specific evaluations of the polynomials are discussed.
description: v4: A more detailed exposition
TRIVIA: visualizing reputation profiles to detect malicious sellers in electronic marketplaces
Creators: name: Sänger, Johannes
name: Pernul, Günther
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: Reputation systems; Robustness; Attacks; Visual analytics
subject: 004 Informatik

description: Reputation systems are an essential part of electronic marketplaces that provide a valuable method to identify honest sellers and punish malicious actors. Due to the continuous improvement of the computation models applied, advanced reputation systems have become non-transparent and incomprehensible to the end-user. As a consequence, users become skeptical and lose their trust toward the reputation system. In this work, we are taking a step to increase the transparency of reputation systems by means of providing interactive visual representations of seller reputation profiles. We thereto propose TRIVIA - a visual analytics tool to evaluate seller reputation. Besides enhancing transparency, our results show that through incorporating the visual-cognitive capabilities of a human analyst and the computing power of a machine in TRIVIA, malicious sellers can be reliably identified. In this way we provide a new perspective on how the problem of robustness could be addressed.
description: http://creativecommons.org/licenses/by/4.0/
Mixed Artin-Tate motives with finite coefficients
Creators: name: Positselski, Leonid
Publisher: name: arXiv
Year: 2010
Subjects: subject: K-Theory and Homology (math.KT)
subject: Algebraic Geometry (math.AG)
subject: Category Theory (math.CT)
subject: FOS: Mathematics

description: The goal of this paper is to give an explicit description of the triangulated categories of Tate and Artin-Tate motives with finite coefficients Z/m over a field K containing a primitive m-root of unity as the derived categories of exact categories of filtered modules over the absolute Galois group of K with certain restrictions on the successive quotients. This description is conditional upon (and its validity is equivalent to) certain Koszulity hypotheses about the Milnor K-theory/Galois cohomology of K. This paper also purports to explain what it means for an arbitrary nonnegatively graded ring to be Koszul. Exact categories, silly filtrations, and the K(π,1)-conjecture are discussed in the appendices. Tate motives with integral coefficients are considered in the "Conclusions" section.
description: LaTeX 2e with pb-diagram.sty, 88 pages, 6+1 commutative diagrams; v.3: additions in the "conclusions" section, other small improvements; v.4: subsection 0.14 inserted in the Introduction, corollary added in subsection 7.3, section 9 expanded; v.5: two references added, several misprints corrected -- this is intended as the final version; v.6: several misprints corrected in section 4
Solventless synthesis of 1-(α-aminoalkyl) naphthols, betti bases, catalyzed by nanoparticle Fe3O4 at room temperature
Creators: name: Mommahed Heravi, Majid
name: Janati, Fatemeh
name: Shokraei, Ahmad Mir
Publisher: name: figshare
Year: 2022
Subjects: subject: 30503 Organic Chemical Synthesis
subject: FOS: Chemical sciences
subject: 30302 Nanochemistry and Supramolecular Chemistry
subject: 30203 Inorganic Green Chemistry
subject: 30701 Quantum Chemistry
subject: 39904 Organometallic Chemistry
subject: Organic Chemistry
subject: 30502 Natural Products Chemistry
subject: 30599 Organic Chemistry not elsewhere classified
subject: 30205 Non-metal Chemistry
subject: Nuclear Chemistry
subject: 30504 Organic Green Chemistry
subject: 30303 Optical Properties of Materials

description: A series of 1-(a-aminoalkyl) naphthols were synthesized expeditiously in good yields and selectivity from 2-naphthol, alkylamines and aldehydes in the presence of nanoparticle fe3o4 at room temperature in solvent-free conditions.
Ultrastrong light-matter coupling at terahertz frequencies with split ring resonators and inter-Landau level transitions
Creators: name: Scalari, G.
name: Maissen, C.
name: Hagenmüller, D.
name: De Liberato, S.
name: Ciuti, C.
name: Reichl, C.
name: Wegscheider, W.
name: Schuh, Dieter
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: 530 Physik

description: We study strong light-matter coupling at terahertz frequencies employing a system based on an array of deeply subwavelength split ring resonators deposited on top of an ensemble of modulation-doped quantum wells. By applying a magnetic field parallel to the epitaxial growth axis, at low temperatures, Landau Levels are formed. We probe the interaction of the inter-Landau level transitions with the resonators modes, measuring a normalized coupling ratio Ωωc=0.58 between the inter-Landau level frequency ωc and the Rabi frequency Ω of the system. The physics of the system is studied as a function of the metasurface composition and of the number of quantum wells. We demonstrate that the light-matter coupling strength is basically independent from the metamaterial lattice spacing.
Transversality for Holomorphic Supercurves
Creators: name: Groeger, Josua
Publisher: name: arXiv
Year: 2011
Subjects: subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics
subject: 53D35, 58C15

description: We study holomorphic supercurves, which are motivated by supergeometry as a natural generalisation of holomorphic curves. We prove that, upon perturbing the defining equations by making them depend on a connection, the corresponding linearised operator is generically surjective. By this transversality result, we show that the resulting moduli spaces are oriented finite dimensional smooth manifolds. Finally, we examine how they depend on the choice of generic data.
description: 25 pages
Investigating software developers' understanding of open source software licensing
Creators: name: Almeida, Daniel A.
Publisher: name: University of British Columbia
Year: 2017

description: Software provided under open source licenses is widely used, from forming high-profile stand-alone applications (e.g., Mozilla Firefox) to being embedded in commercial offerings (e.g., network routers). Despite the high frequency of use of open source licenses, there has been little work about whether software developers understand the open source licenses they use. To help understand whether or not developers understand the open source licenses they use, I conducted a survey that posed development scenarios involving three popular open source licenses (GNU GPL 3.0, GNU LGPL 3.0 and MPL 2.0) both alone and in combination. The 375 respondents to the survey, who were largely developers, gave answers consistent with those of a legal expert's opinion in 62% of 42 cases. Although developers clearly understood cases involving one license, they struggled when multiple licenses were involved. To understand the context in which licensing issues arise in practice, I analyzed real-world questions posed by developers on online question-and-answer communities. The analysis of these questions indicate that licensing issues can constrain software evolution and technical decisions can have an impact on future licensing issues. Finally, I interviewed software developers in industry to understand how developers reason about and handle license incompatibility in practice. The developers I interviewed are cautious of restrictive licenses. To identify potential licensing issues, these developers rely on licensing guidelines provided by their organization and sometimes use specialized tools to automatically detect licensing issues in their projects. When faced with a situation in which a component that suits their needs is not compatible, developers tend to look for alternative components made available by open source communities. They sometimes leverage the technical architecture of their projects to enable the use of components under restrictive licenses and might rewrite the required functionality if necessary. An analysis of the results indicate a need for tool support to help guide developers in understanding the structure of the code and the technical details of a project while taking into account the exact requirements imposed by the licenses involved.
On rings of integers generated by their units
Creators: name: Frei, Christopher
Publisher: name: arXiv
Year: 2010
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11R04 (Primary) 11R27 (Secondary)

description: We give an affirmative answer to the following question by Jarden and Narkiewicz: Is it true that every number field has a finite extension L such that the ring of integers of L is generated by its units (as a ring)? As a part of the proof, we generalize a theorem by Hinz on power-free values of polynomials in number fields.
description: 15 pages
MPEC 2023-J03 : 2023 HK7
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2023 HK7

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Electronic spectroscopy of 9,10-dichloroanthracene inside helium droplets
Creators: name: Pentlehner, D.
name: Slenczka, Alkwin
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: 540 Chemie

description: The spectroscopy of molecules doped into superfluid helium droplets provides information on both, the dopant molecule and the helium environment. Electronic spectra of 9,10-dichloroanthracene in helium droplets are presented and compared with corresponding gas phase spectra to unravel the influence of the helium environment. The combined investigation of fluorescence excitation and dispersed emission provides information on dynamic processes in addition to energetic conditions. For vibronic states, the helium induced decay channels dominate over all intramolecular channels that contribute to the gas phase behavior. In addition to the triplet splitting caused by the Cl isotopes, a fine structure resolved for all transitions in the fluorescence excitation spectrum was found, which is the signature of microsolvation of this compound in helium droplets. This fine structure is identified as a single pure molecular transition accompanied by a sharply structured phonon wing. The corresponding fine structure measured for bare anthracene shows remarkable differences.
Counting statistics and dephasing transition in an electronic Mach-Zehnder interferometer
Creators: name: Helzel, Andreas
name: Litvin, Leonid
name: Levkivskyi, I. P.
name: Sukhorukov, E. V.
name: Wegscheider, Werner
name: Strunk, Christoph
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: 530 Physik

description: It was recently suggested that a novel type of phase transition may occur in the visibility of electronic Mach-Zehnder interferometers. Here, we present experimental evidence for the existence of this transition. The transition is induced by strongly non-Gaussian noise that originates from the strong coupling of a quantum point contact to the interferometer. We provide a transparent physical picture of the effect by exploiting a close analogy to the neutrino oscillations of particle physics. In addition, our experiment constitutes a probe of the singularity of the elusive full counting statistics of a quantum point contact.
Local ab initio methods for calculating optical bandgaps in periodic systems. II. Periodic density fitted local configuration interaction singles method for solids
Creators: name: Lorenz, Marco
name: Maschio, Lorenzo
name: Usvyat, Denis
name: Schütz, Martin
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: 540 Chemie

description: We present a density fitted local configuration interaction singles (CIS) method for calculating optical bandgaps in 3D-periodic systems. We employ an Ewald technique to carry out infinite lattice summations for the exciton-exciton interaction, and robust product-density specific local density fitting in direct space for the electron-hole interaction. Moreover, we propose an alternative to the usual cyclic model with Born-von Karman periodic boundary conditions, the so called Wigner-Seitz supercell truncated infinite model, which exhibits much improved convergence of the CISexcitation energy with respect to the size of the supercell. Test calculations on a series of prototypical systems demonstrate that the method at the present stage can be used to calculate the excitonic bandgaps of 3D periodic systems with up to a dozen atoms in the unit cell, ranging from wide-gap insulators to semiconductors.
Outliers in the spectrum of iid matrices with bounded rank perturbations
Creators: name: Tao, Terence
Publisher: name: arXiv
Year: 2010
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60B20

description: It is known that if one perturbs a large iid random matrix by a bounded rank error, then the majority of the eigenvalues will remain distributed according to the circular law. However, the bounded rank perturbation may also create one or more outlier eigenvalues. We show that if the perturbation is small, then the outlier eigenvalues are created next to the outlier eigenvalues of the bounded rank perturbation; but if the perturbation is large, then many more outliers can be created, and their law is governed by the zeroes of a random Laurent series with Gaussian coefficients. On the other hand, these outliers may be eliminated by enforcing a row sum condition on the final matrix.
description: 26 pages, 5 figures. As pointed out to the author by Jean Rochet, the previous fix to Lemma 2.3 was incorrect, and has been replaced by a corrected fix
The orbital-specific virtual local triples correction: OSV-L(T)
Creators: name: Schütz, Martin
name: Yang, Jun
name: Chan, Garnet Kin-Lic
name: Manby, Frederick R.
name: Werner, Hans-Joachim
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: 540 Chemie

description: A local method based on orbital specific virtuals (OSVs) for calculating the perturbative triples correction in local coupled cluster calculations is presented. In contrast to the previous approach based on projected atomic orbitals (PAOs), described by Schütz [J. Chem. Phys.113, 9986 (Year: 2000)]10.1063/1.1323265, the new scheme works without any ad hoc truncations of the virtual space to domains. A single threshold defines the pair and triple specific virtual spaces completely and automatically. It is demonstrated that the computational cost of the method scales linearly with molecular size. Employing the recommended threshold a similar fraction of the correlation energy is recovered as with the original PAO method at a somewhat lower cost. A benchmark for 52 reactions demonstrates that for reaction energies the intrinsic accuracy of the coupled cluster with singles and doubles excitations and a perturbative treatment of triples excitations method can be reached by OSV-local coupled cluster theory with singles and doubles and perturbative triples, provided a MP2 correction is applied that accounts for basis set incompleteness errors as well as for remaining domain errors. As an application example the interaction energies of the guanine-cytosine dimers in the Watson-Crick and stacked arrangements are investigated at the level of local coupled cluster theory with singles and doubles and perturbative triples. Based on these calculations we propose new complete-basis-set-limit estimates for these interaction energies at this level of theory.
Local CC2 response method based on the Laplace transform: Orbital-relaxed first-orderproperties for excited states
Creators: name: Ledermüller, Katrin
name: Kats, Daniel
name: Schütz, Martin
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: 540 Chemie

description: A multistate local CC2 response method for the calculation of orbital-relaxed first order properties is presented for ground and electronically excited states. It enables the treatment of excited state properties including orbital relaxation for extended molecular systems and is a major step on the way towards analytic gradients with respect to nuclear displacements. The Laplace transform method is employed to partition the eigenvalue problem and the lambda equations, i.e., the doubles parts of these equations are inverted on-the-fly, leaving only the corresponding effective singles equations to be solved iteratively. Furthermore, the state specific local approximations are adaptive. Density-fitting is utilized to decompose the electron-repulsion integrals. The accuracy of the local approximation is tested and the efficiency of the new code is demonstrated on the example of an organic sensitizer for solar-cell applications, which consists of about 100 atoms.
Compactness for Holomorphic Supercurves
Creators: name: Groeger, Josua
Publisher: name: arXiv
Year: 2011
Subjects: subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics

description: We study the compactness problem for moduli spaces of holomorphic supercurves which, being motivated by supergeometry, are perturbed such as to allow for transversality. We give an explicit construction of limiting objects for sequences of holomorphic supercurves and prove that, in important cases, every such sequence has a convergent subsequence provided that a suitable extension of the classical energy is uniformly bounded. This is a version of Gromov compactness. Finally, we introduce a topology on the moduli spaces enlarged by the limiting objects which makes these spaces compact and metrisable.
description: 38 pages
Optical bistability involving planar metamaterial with broken structural symmetry
Creators: name: Tuz, Vladimir R.
name: Prosvirnin, Sergey L.
name: Kochetova, Lyudmila A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We report on a bistable light transmission through a planar metamaterial composed of a metal pattern of weakly asymmetric elements placed on a nonlinear substrate. Such structure bears the Fano-like sharp resonance response of a trapped-mode excitation. The feedback required for bistability is provided by the coupling between the strong antiphased trapped-mode-resonance currents excited on the metal elements and the intensity of inner field in the nonlinear substrate.
description: 4 pages, 4 figures
The component sizes of a critical random graph with given degree sequence
Creators: name: Joseph, Adrien
Publisher: name: arXiv
Year: 2010
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: Consider a critical random multigraph $\mathcal{G}_n$ with $n$ vertices constructed by the configuration model such that its vertex degrees are independent random variables with the same distribution $ν$ (criticality means that the second moment of $ν$ is finite and equals twice its first moment). We specify the scaling limits of the ordered sequence of component sizes of $\mathcal{G}_n$ as $n$ tends to infinity in different cases. When $ν$ has finite third moment, the components sizes rescaled by $n^{-2/3}$ converge to the excursion lengths of a Brownian motion with parabolic drift above past minima, whereas when $ν$ is a power law distribution with exponent $γ\in(3,4)$, the components sizes rescaled by $n^{-(γ-2)/(γ-1)}$ converge to the excursion lengths of a certain nontrivial drifted process with independent increments above past minima. We deduce the asymptotic behavior of the component sizes of a critical random simple graph when $ν$ has finite third moment.
description: Published in at http://dx.doi.org/10.1214/13-AAP985 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Microwave enhanced advanced oxidation treatment of sludge from a municipal wastewater treatment plant
Creators: name: Tan, Hanji
Publisher: name: University of British Columbia
Year: 2017

description: It has been proven that microwave enhanced advanced oxidation process (MW-AOP) has an outstanding treatment efficiency on the organic slurries, such as sewage sludge and dairy manure (liquid portion), yet the treatment efficiencies on different substrates remain unknown. This study was carried out to: 1) identify the effects of MW-AOP on different types of sludge, 2) evaluate the effects of flowrates and solids concentrations on the heating profile, 3) evaluate the MW-AOP treatment efficiencies of secondary sludge at 90 and 110 ºC, and 4) examine the treatment efficiencies of MW-AOP of dairy manure (liquid portion). The study on the sludge was to evaluate treatment efficiencies of different sludge (primary sludge, secondary sludge, and anaerobic digested sludge) and the centrate by the MW-AOP. The results indicated that the secondary sludge was most suitable for the MW-AOP treatment. This is because secondary sludge had the highest number of solids and phosphorus contents, but also yielded the highest soluble materials. The pilot-scale 915 MHz MW-AOP system was used to treat the secondary sludge at 90 and 110ºC, which suggested that higher temperature would favor nutrients release. The dewaterability of treated sludge improved significantly at both temperatures. The pilot-scale 915 MHz continuous flow MW-AOP system was also tested with salt water at different flowrates and salt concentrations to understand the heating and power consumption profile of the system. Among the flowrates (6, 7.5, 9 L/min) and salt concentrations (10 mg/L to 120 mg/L) examined, the total energy consumption increased with an increase of salt concentration, while flowrates had lesser effect. In contrast, the temperature rise was more rapid with lower salt concentrations. The overall heating rate was similar for different flowrates. Similar to secondary sludge, the pilot-scale 915 MHz continuous flow MW-AOP system was used to treat dairy manure (liquid portion). The results suggested a sound treatment efficiency, with an increase from 3% to up to 90% of soluble TP/TP, which enhances subsequent struvite recovery. Both the ratios of soluble TP/TP and of ortho-P/soluble TP were favored by higher temperatures.
Phase Field Models Versus Parametric Front Tracking Methods: Are They Accurate and Computationally Efficient?
Creators: name: Barrett, John W.
name: Garcke, Harald
name: Nürnberg, Robert
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: Phase field models; parametric sharp interface methods; Stefan problem; anisotropy; solidification; crystal growth; numerical simulations; benchmark problems
subject: 510 Mathematik

description: We critically compare the practicality and accuracy of numerical approximations of phase field models and sharp interface models of solidification. Here we focus on Stefan problems, and their quasi-static variants, with applications to crystal growth. New approaches with a high mesh quality for the parametric approximations of the resulting free boundary problems and new stable discretizations of the anisotropic phase field system are taken into account in a comparison involving benchmark problems based on exact solutions of the free boundary problem.
Eigenvectors of tensors and algorithms for Waring decomposition
Creators: name: Oeding, Luke
name: Ottaviani, Giorgio
Publisher: name: arXiv
Year: 2011
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14Q15, 13P15, 15A18, 15A21

description: A Waring decomposition of a (homogeneous) polynomial f is a minimal sum of powers of linear forms expressing f. Under certain conditions, such a decomposition is unique. We discuss some algorithms to compute the Waring decomposition, which are linked to the equation of certain secant varieties and to eigenvectors of tensors. In particular we explicitly decompose a general cubic polynomial in three variables as the sum of five cubes (Sylvester Pentahedral Theorem).
description: 32 pages; three Macaulay2 files as ancillary files. Revised with referee's suggestions. Accepted JSC
Generalized Geologic Map for Land-Use Planning: Greenup County, Kentucky
Creators: name: Carey, Daniel I.
Publisher: name: Kentucky Geological Survey, University of Kentucky
Year: 2007

description: Abstract:
This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.
Exploring the impact of traffic congestion on CO2 emissions in freight distribution networks
Creators: name: Kellner, Florian
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: Distribution network; CO2 emissions; Road freight transportation; Traffic congestion; Online navigation service
subject: 330 Wirtschaft

description: This research quantifies the impact that regular road traffic congestion has on the CO2 emissions of a real-world distribution network, and it studies the consequences when the number of distribution centers changes. For this purpose, this study makes use of a network model allowing for a detailed representation of all relevant transport operations, including production flows between factories and distribution centers, line haul shipments between distribution centers and customers, and round/delivery trips between transshipment points and retailer locations for the last mile. The processed trip and traffic information does not rely on standard traffic data collection approaches, such as interviews, in situ technologies, or floating car data, but the road traffic data are retrieved from an online navigation service, such as Bing Maps, Google Maps, Inrix, Here, and TomTom. This study proves that online navigation services may considerably contribute to future research projects analyzing CO2 sensitivities and greenhouse gas cutting opportunities in logistics networks.
Liquid-induced damping of mechanical feedback effects in single electron tunneling through a suspended carbon nanotube
Creators: name: Schmid, Daniel R.
name: Stiller, Peter L.
name: Strunk, Christoph
name: Hüttel, Andreas K.
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: damping
subject: 530 Physik

description: In single electron tunneling through clean, suspended carbon nanotube devices at low temperature, distinct switching phenomena have regularly been observed. These can be explained via strong interaction of single electron tunneling and vibrational motion of the nanotube. We present measurements on a highly stable nanotube device, subsequently recorded in the vacuum chamber of a dilution refrigerator and immersed in the 3He/ 4He mixture of a second dilution refrigerator. The switching phenomena are absent when the sample is kept in the viscous liquid, additionally supporting the interpretation of dc-driven vibration. Transport measurements in liquid helium can thus be used for finite bias spectroscopy where otherwise the mechanical effects would dominate the current.
Bounds on Scalar Masses in Theories of Moduli Stabilization
Creators: name: Acharya, Bobby Samir
name: Kane, Gordon
name: Kuflik, Eric
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In recent years it has been realised that pre-BBN decays of moduli can be a significant source of dark matter production, giving a `non-thermal WIMP miracle' and substantially reduced fine-tuning in cosmological axion physics. We study moduli masses and sharpen the claim that moduli dominated the pre-BBN Universe. We conjecture that in any string theory with stabilized moduli there will be at least one modulus field whose mass is of order (or less than) the gravitino mass. Cosmology then generically requires the gravitino mass not be less than about 30 TeV and the cosmological history of the Universe is non-thermal prior to BBN. Stable LSP's produced in these decays can account for the observed dark matter if they are `wino-like.' We briefly consider implications for the LHC, rare decays, and dark matter direct detection and point out that these results could prove challenging for models attempting to realize gauge mediation in string theory.
description: 7 pages. v3: published version
Sclerosis tuberous of Bourneville : a case report
Creators: name: HOUDA, MATTICHE
Publisher: name: EURORAD
Year: 2014
Subjects: subject: Ear / Nose / Throat
subject: Musculoskeletal soft tissue
subject: Neuroradiology brain
subject: MR
subject: Percutaneous
subject: Diagnostic procedure
subject: Tissue characterisation

description: Clinical History Image Findings Discussion Find Diagnosis Differential Diagnosis
description: male, 25 years
description: Clinical History: A 25-year-old man with no previous medical history was admitted to the neurology department due to an increased intracranial pressure. Achromic cutaneous spot on the thigh and facial brownish papules were noted on patient as well as patientÃ¢ÂÂs father ( f... Final Diagnosis: Sclerosis tuberous of Bourneville
Development of an epoxy-based microfluidic device for automated circulating tumour cell separation
Creators: name: Yan, Justin Phillip
Publisher: name: University of British Columbia
Year: 2017

description: Circulating tumour cells (CTCs) are cancer cells shed from a primary tumour site into the bloodstream, where they have the potential to invade other tissues in the body, and thus become the seed of metastases. CTCs have great potential to monitor disease progression and guide cancer treatment, but a key technical challenge for their isolation and characterization is their extreme rarity in blood. CTCs are commonly enriched using immunoaffinity, which while being highly selective, may fail to capture cells that have weak antigen expression. The biophysical properties of CTCs offer a compelling alternative to immunoenrichment. CTCs are much larger in size than erythrocytes, but are similar to leukocytes. Owing to their epithelial origin however, CTCs are likely to be more rigid than leukocytes which allows for deformability based methods to separate these cells. Previously, our group has demonstrated the continuous flow microfluidic ratchet device for deformability based separation of CTCs. Here, an improved version of the device has been developed to be compatible with pre-enrichment methods, allowing for a dramatic increase in throughput. While similar in principle to the previous version, this work specifically improves the design of the sample infusion area to increase the points of contact between the sorting matrix and sample inlet, in order to prevent the accumulation of cell debris. Using this new design, epoxy resin devices and supporting instrumentation were developed to provide a pathway towards scale-up production and automation. These combined improvements allow biology laboratory technicians to enrich CTCs without significant training. The improved device is capable of capturing > 80% CTCs from whole blood at a throughput of 1 mL/hr, which when combined with a red blood cell lysis pre-enrichment step, increases to 8 mL/hr. Finally, devices were used to enrich CTCs from patients with metastatic castration-resistant prostate cancer. CTCs were found in 3 out of 11 patients, with an average count of 78. The enriched cells were further processed to perform single cell genomic sequencing where CTCs were found to contain driver mutations including those commonly associated with prostate cancer.
Dendroidal sets as models for connective spectra
Creators: name: Basic, M.
name: Nikolaus, Thomas
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: dendroidal sets, connective spectra, model structure
subject: 510 Mathematik

description: Dendroidal sets have been introduced as a combinatorial model for homotopy coherent operads. We introduce the notion of fully Kan dendroidal sets and show that there is a model structure on the category of dendroidal sets with fibrant objects given by fully Kan dendroidal sets. Moreover we show that the resulting homotopy theory is equivalent to the homotopy theory of connective spectra.