cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Tailored nanoantennas for directional Raman studies of individual carbon nanotubes
Creators: name: Paradiso, N.
name: Yaghobian, Fatemeh
name: Lange, Christoph
name: Korn, Tobias
name: Schüller, Christian
name: Huber, Rupert
name: Strunk, Christoph
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: 530 Physik

description: We exploit the near field enhancement of nanoantennas to investigate the Raman spectra of otherwise not optically detectable carbon nanotubes (CNTs). We demonstrate that a top-down fabrication approach is particularly promising when applied to CNTs, owing to the sharp dependence of the scattered intensity on the angle between incident light polarization and CNT axis. In contrast to tip enhancement techniques, our method enables us to control the light polarization in the sample plane, locally amplifying and rotating the incident field and hence optimizing the Raman signal. Such promising features are confirmed by numerical simulations presented here. The relative ease of fabrication and alignment makes this technique suitable for the realization of integrated devices that combine scanning probe, optical, and transport characterization.
SPIDER: Probing the Early Universe with a Suborbital Polarimeter
Creators: name: Fraisse, A. A.
name: Ade, P. A. R.
name: Amiri, M.
name: Benton, S. J.
name: Bock, J. J.
name: Bond, J. R.
name: Bonetti, J. A.
name: Bryan, S.
name: Burger, B.
name: Chiang, H. C.
name: Clark, C. N.
name: Contaldi, C. R.
name: Crill, B. P.
name: Davis, G.
name: Doré, O.
name: Farhang, M.
name: Filippini, J. P.
name: Fissel, L. M.
name: Gandilo, N. N.
name: Golwala, S.
name: Gudmundsson, J. E.
name: Hasselfield, M.
name: Hilton, G.
name: Holmes, W.
name: Hristov, V. V.
name: Irwin, K.
name: Jones, W. C.
name: Kuo, C. L.
name: MacTavish, C. J.
name: Mason, P. V.
name: Montroy, T. E.
name: Morford, T. A.
name: Netterfield, C. B.
name: O'Dea, D. T.
name: Rahlin, A. S.
name: Reintsema, C.
name: Ruhl, J. E.
name: Runyan, M. C.
name: Schenker, M. A.
name: Shariff, J. A.
name: Soler, J. D.
name: Trangsrud, A.
name: Tucker, C.
name: Tucker, R. S.
name: Turner, A. D.
name: Wiebe, D.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We evaluate the ability of SPIDER, a balloon-borne polarimeter, to detect a divergence-free polarization pattern ("B-modes") in the Cosmic Microwave Background (CMB). In the inflationary scenario, the amplitude of this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. We show that the expected level of systematic error in the SPIDER instrument is significantly below the amplitude of an interesting cosmological signal with r=0.03. We present a scanning strategy that enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while accessing a relatively wide range of angular scales. Evaluating the amplitude of the polarized Galactic emission in the SPIDER field, we conclude that the polarized emission from interstellar dust is as bright or brighter than the cosmological signal at all SPIDER frequencies (90 GHz, 150 GHz, and 280 GHz), a situation similar to that found in the "Southern Hole." We show that two ~20-day flights of the SPIDER instrument can constrain the amplitude of the B-mode signal to r<0.03 (99% CL) even when foreground contamination is taken into account. In the absence of foregrounds, the same limit can be reached after one 20-day flight.
description: 29 pages, 8 figures, 4 tables; v2: matches published version, flight schedule updated, two typos fixed in Table 2, references and minor clarifications added, results unchanged
Dual conformal symmetry on the light-cone
Creators: name: Derkachov, S. E.
name: Korchemsky, G. P.
name: Manashov, Alexander
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: 530 Physik

description: We study the properties of conformal operators in the SL(2) sector of planar N=4 SYM and its supersymmetric SL(2|2) extension. The correlation functions of these operators and their form factors with respect to asymptotic on-shell states are determined in the appropriate limit by two different polynomials which can be identified as eigenstates of the dilatation operator in the coordinate and momentum representations, respectively. We argue that, in virtue of integrability of the dilatation operator, the two polynomials satisfy a duality relation -- they are proportional to each other upon an appropriate identification of momenta and coordinates. Combined with the conventional N=4 superconformal symmetry, this leads to the dual superconformal symmetry of the dilatation operator. We demonstrate that this symmetry is powerful enough to fix the eigenspectrum of the dilatation operator to the lowest order in the coupling. We use the relation between the one-loop dilatation operator and Heisenberg spin chain to show that, to lowest order in the coupling, the dual symmetry is generated by the Baxter Q-operator in the limit of large spectral parameter.
description: SCOAP3
Dissipative dynamics in a quantum bistable system: Crossover from weak to strong damping
Creators: name: Magazzù, Luca
name: Valenti, Davide
name: Spagnolo, Bernardo
name: Grifoni, Milena
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: 530 Physik

description: The dissipative dynamics of a quantum bistable system coupled to a Ohmic heat bath is investigated beyond the spin-boson approximation. Within the path-integral approach to quantum dissipation, we propose an approximation scheme which exploits the separation of time scales between intra- and interwell (tunneling) dynamics. The resulting generalized master equation for the populations in a space localized basis enables us to investigate a wide range of temperatures and system-environment coupling strengths. A phase diagram in the coupling-temperature space is provided to give a comprehensive account of the different dynamical regimes.
Non-linear spin-wave excitations at low magnetic bias fields
Creators: name: Back, Christian H.
name: Bauer, Hans G.
name: Majchrak, Peter
name: Kachel, Torsten
name: Woltersdorf, Georg
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: Physical sciences, Applied physics, Condensed matter
subject: 530 Physik

description: Nonlinear magnetization dynamics is essential for the operation of numerous spintronic devices ranging from magnetic memory to spin torque microwave generators. Examples are microwave-assisted switching of magnetic structures and the generation of spin currents at low bias fields by high-amplitude ferromagnetic resonance. Here we use X-ray magnetic circular dichroism to determine the number density of excited magnons in magnetically soft Ni80Fe20 thin films. Our data show that the common model of nonlinear ferromagnetic resonance is not adequate for the description of the nonlinear behaviour in the low magnetic field limit. Here we derive a model of parametric spin-wave excitation, which correctly predicts nonlinear threshold amplitudes and decay rates at high and at low magnetic bias fields. In fact, a series of critical spin-wave modes with fast oscillations of the amplitude and phase is found, generalizing the theory of parametric spin-wave excitation to large modulation amplitudes.
Quantum mechanics of null polygonal Wilson loops
Creators: name: Belitsky, A. V.
name: Derkachov, S. E.
name: Manashov, Alexander
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: 530 Physik

description: Scattering amplitudes in maximally supersymmetric gauge theory are dual to super-Wilson loops on null polygonal contours. The operator product expansion for the latter revealed that their dynamics is governed by the evolution of multiparticle GKP excitations. They were shown to emerge from the spectral problem of an underlying open spin chain. In this work we solve this model with the help of the Baxter Q-operator and Sklyanin's Separation of Variables methods. We provide an explicit construction for eigenfunctions and eigenvalues of GKP excitations. We demonstrate how the former define the so-called multiparticle hexagon transitions in super-Wison loops and prove their factorized form suggested earlier.
description: SCOAP3
A 22-year Southern Sky Survey for Transient and Variable Radio Sources using the Molonglo Observatory Synthesis Telescope
Creators: name: Bannister, Keith
name: Murphy, Tara
name: Gaensler, Bryan M.
name: Hunstead, Richard
name: Chatterjee, Shami
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We describe a 22-year survey for variable and transient radio sources, performed with archival images taken with the Molonglo Observatory Synthesis Telescope (MOST). This survey covers $2775 \unit{deg^2}$ of the sky south of $δ< -30\degree$ at an observing frequency of 843 MHz, an angular resolution of $45 \times 45 \csc | δ| \unit{arcsec^2}$ and a sensitivity of $5 σ\geq 14 \unit{mJy beam^{-1}}$. We describe a technique to compensate for image gain error, along with statistical techniques to check and classify variability in a population of light curves, with applicability to any image-based radio variability survey. Among radio light curves for almost 30000 sources, we present 53 highly variable sources and 15 transient sources. Only 3 of the transient sources, and none of the variable sources have been previously identified as transient or variable. Many of our variable sources are suspected scintillating Active Galactic Nuclei. We have identified three variable sources and one transient source that are likely to be associated with star forming galaxies at $z \simeq 0.05$, but whose implied luminosity is higher than the most luminous known radio supernova (SN1979C) by an order of magnitude. We also find a class of variable and transient source with no optical counterparts.
description: Accepted for publication in MNRAS. 34 pages, 30 figures, 7 tables
Microcavity design for low threshold polariton condensation with ultrashort optical pulse excitation
Creators: name: Pöllmann, Christoph
name: Leierseder, Ursula
name: Galopin, E.
name: Lemaître, A.
name: Amo, A.
name: Bloch, J.
name: Huber, Rupert
name: Ménard, J.-M.
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: 530 Physik

description: We present a microcavity structure with a shifted photonic stop-band to enable efficient non-resonant injection of a polariton condensate with spectrally broad femtosecond pulses. The concept is demonstrated theoretically and confirmed experimentally for a planar GaAs/AlGaAs multilayer heterostructure pumped with ultrashort near-infrared pulses while photoluminescence is collected to monitor the optically injected polariton density. As the excitation wavelength is scanned, a regime of polariton condensation can be reached in our structure at a consistently lower fluence threshold than in a state-of-the-art conventional microcavity. Our microcavity design improves the polariton injection efficiency by a factor of 4, as compared to a conventional microcavity design, when broad excitation pulses are centered at a wavelength of λ = 740 nm. Most remarkably, this improvement factor reaches 270 when the excitation wavelength is centered at 750 nm.
The influence of age and sex on genetic associations with adult body size and shape: a large-scale genome-wide interaction study
Creators: name: Winkler, Thomas W.
name: Heid, Iris M.
name: Gorski, Mathias
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: 610 Medizin

description: Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age- and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to ~2.8M SNPs with BMI and WHRadjBMI in four strata (men ≤50y, men >50y, women ≤50y, women >50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR<5%) age-specific effects, of which 11 had larger effects in younger (<50y) than in older adults (≥50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may provide further insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.
Reconstructed Jets at RHIC
Creators: name: Salur, Sevil
Publisher: name: arXiv
Year: 2010
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: To precisely measure jets over a large background such as pile up in high luminosity p+p collisions at LHC, a new generation of jet reconstruction algorithms is developed. These algorithms are also applicable to reconstruct jets in the heavy ion environment where large event multiplicities are produced. Energy loss in the medium created in heavy ion collisions are already observed indirectly via inclusive hadron distributions and di-hadron correlations. Jets can be used to study this energy loss in detail with reduced biases. We review the latest results on jet-medium interactions as seen in A+A collisions at RHIC, focusing on the recent progress on jet reconstruction in heavy ion collisions.
description: Proceedings for the 26th Winter Workshop on Nuclear Dynamics
Li17Sb13S28: A New Lithium Ion Conductor and addition to the Phase Diagram Li2S–Sb2S3
Creators: name: Huber, Sebastian
name: Pfitzner, Arno
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: antimony;ion conductor;lithium;sulfide;thiometalate
subject: 540 Chemie

description: Li17Sb13S28 was synthesized by solid-state reaction of stoichiometric amounts of anhydrous Li2S and Sb2S3. The crystal structure of Li17Sb13S28 was determined from dark-red single crystals at room temperature. The title compound crystallizes in the monoclinic space group C2/m (no. 12) with a=12.765(2) Å, b=11.6195(8) Å, c=9.2564(9) Å, β=119.665(6)°, V=1193.0(2) Å3, and Z=4 (data at 20 °C, lattice constants from powder diffraction). The crystal structure contains one cation site with a mixed occupation by Li and Sb, and one with an antimony split position. Antimony and sulfur form slightly distorted tetragonal bipyramidal [SbS5E] units (E=free electron pair). Six of these units are arranged around a vacancy in the anion substructure. The lone electron pairs E of the antimony(III) cations are arranged around these vacancies. Thus, a variant of the rock salt structure type with ordered vacancies in the anionic substructure results. Impedance spectroscopic measurements of Li17Sb13S28 show a specific conductivity of 2.9×10−9 Ω−1 cm−1 at 323 K and of 7.9×10−6 Ω−1 cm−1 at 563 K, the corresponding activation energy is EA=0.4 eV below 403 K and EA=0.6 eV above. Raman spectra are dominated by the Sb[BOND]S stretching modes of the [SbS5] units at 315 and 341 cm−1 at room temperature. Differential thermal analysis (DTA) measurements of Li17Sb13S28 indicate peritectic melting at 854 K.
Young adult males' evaluation of their sexual health education : an enhanced critical incident technique analysis
Creators: name: Cholewa, Tymarah
Publisher: name: University of British Columbia
Year: 2017

description: The purpose of this study is to learn from young adult males what critical incidents of sexual health education (SHE) helped, hindered, and were wished for, regarding their personal understanding of their own gender identity and sexuality. With the dramatic disparity in sexual health outcomes between young men and women, it seems sexual health education is not as effective at increasing health seeking behaviours, preventing sexually transmitted diseases, or creating and fostering healthy sexual identity development for males as it is for females. Using the Enhanced Critical Incident Technique analysis (ECIT) eleven young adult males (ages 18-25) were asked what helped, hindered, and what they wished for from the SHE they received in British Columbia (BC) public schools. This was done to better understand how to better reach males in sexual health education. There was a total of 205 critical incidents (CIs), with 75 helping incidents, 58 hindering incidents, and 72 wish list items (WL). The CIs and WL items are organized into 13 categories that reached the required 25% participation rate (Borgen & Amundson, 1984): five helping categories, two hindering categories, and six wish list categories. The six helping categories are Harm Reduction, Normalization of the Male Body, Condom Demo, Anatomy and Function of Female Body, and Anonymous Question Box. The two hindering categories are Instructor and Delivery and Peer Influence and Behaviour. The six wish list categories are Gender Identity, LGBTQ Inclusive, Class Size, Continuous Education, Sex Positivity and Normalization, and Consent. The resulting data suggests that sexual health education that is continuous, sex-positive, skills-based, and is taught by a normalizing and comfortable instructor in a safe and confidential environment would be most desirable and engaging for young males.
Some remarks on the planar Kouchnirenko's Theorem
Creators: name: Greuel, Gert-Martin
name: Duc, Nguyen Hong
Publisher: name: arXiv
Year: 2010
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: We consider different notions of non-degeneracy, as introduced by Kouchnirenko (NND), Wall (INND) and Beelen-Pellikaan (WNND) for plane curve singularities $\{f(x,y) = 0\}$ and introduce the new notion of weighted homogeneous Newton non-degeneracy (WHNND). It is known that the Milnor number $μ$ resp. the delta-invariant $δ$ can be computed by explicit formulas $μ_N$ resp. $δ_N$ from the Newton diagram of $f$ if $f$ is NND resp. WNND. It was however unknown whether the equalities $μ=μ_N$ resp. $δ=δ_N$ can be characterized by a certain non-degeneracy condition on $f$ and, if so, by which one. We show that $μ=μ_N$ resp. $δ=δ_N$ is equivalent to INND resp. WHNND and give some applications and interesting examples related to the existence of "wild vanishing cycles". Although the results are new in any characteristic, the main difficulties arise in positive characteristic.
description: 23 pages, 2 figures. Final version
Achievable Outage Rate Regions for the MISO Interference Channel
Creators: name: Lindblom, Johannes
name: Karipidis, Eleftherios
name: Larsson, Erik G.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: We consider the slow-fading two-user multiple-input single-output (MISO) interference channel. We want to understand which rate points can be achieved, allowing a non-zero outage probability. We do so by defining four different outage rate regions. The definitions differ on whether the rates are declared in outage jointly or individually and whether the transmitters have instantaneous or statistical channel state information (CSI). The focus is on the instantaneous CSI case with individual outage, where we propose a stochastic mapping from the rate point and the channel realization to the beamforming vectors. A major contribution is that we prove that the stochastic component of this mapping is independent of the actual channel realization.
description: Accepted for publication in IEEE Wireless Communications Letters
Studies of Stellar Collapse and Black Hole Formation with the Open-Source Code GR1D
Creators: name: Ott, Christian D.
name: O'Connor, Evan
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We discuss results from simulations of black hole formation in failing core-collapse supernovae performed with the code GR1D, a new open-source Eulerian spherically-symmetric general-relativistic hydrodynamics code. GR1D includes rotation in an approximate way (1.5D), comes with multiple finite-temperature nuclear equations of state (EOS), and treats neutrinos in the post-core-bounce phase via a 3-flavor leakage scheme and a heating prescription. We chose the favored K_0=220 MeV-variant of the Lattimer & Swesty (1990) EOS and present collapse calculations using the progenitor models of Limongi & Chieffi (2006). We show that there is no direct (or ``prompt'') black hole formation in the collapse of ordinary massive stars (8 M_Sun ~< M_ZAMS ~< 100 M_Sun) and present first results from black hole formation simulations that include rotation.
description: 8 pages, 2 figures. Published in the proceedings of the OMEG10 symposium, Osaka, Japan, March 8-10, 2010
Autodisplay of human hyaluronidase Hyal-1 on Escherichia coli and identification of plant-derived enzyme inhibitors
Creators: name: Orlando, Zoya
name: Lengers, Isabelle
name: Melzig, Matthias F.
name: Buschauer, Armin
name: Hensel, Andreas
name: Jose, Joachim
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: Autodisplay; Hyal-1; hyaluronan; natural inhibitors
subject: 615 Pharmazie

description: Hyaluronan (HA) is the main component of the extracellular matrix (ECM). Depending on its chain size, it is generally accepted to exert diverse effects. High molecular weight HA is anti-angiogenic, immunosuppressive and anti-inflammatory, while lower fragments are angiogenic and inflammatory. Human hyaluronidase Hyal-1 (Hyal-1) is one of the main enzymes in the metabolism of HA. This makes Hyal-1 an interesting target. Not only for functional and mechanistic studies, but also for drug development. In this work, Hyal-1 was expressed on the surface of E. coli, by applying Autodisplay, to overcome formation of inactive “inclusion bodies”. With the cells displaying Hyal-1 an activity assay was performed using “stains-all” dye. Subsequently, the inhibitory effects of four saponins and 14 plant extracts on the activity of surface displayed Hyal-1 were evaluated. The determined IC50 values were 177 µM for glycyrrhizic acid, 108 µM for gypsophila saponin 2, 371 µM for SA1657 and 296 µM for SA1641. Malvae sylvestris flos, Equiseti herba and Ononidis radix extracts showed IC50 values between 1.4 and 1.7 mg/mL. In summary, Autodisplay enabled the expression of functional human target protein Hyal-1 in E. coli and facilitated an accelerated testing of potential inhibitors.
title: I am The Sun And Cannot Be Gazed Upon Fixedly: Art And The Spectral Power Of The Derivative
Creators: name: Vasseur, Roman
Publisher: name: Goldsmiths, University of London
Year: 2018

description: This PhD claims that art and cultural production, more broadly, are irrevocably changed now that the logic of the derivative is seeded in and transmitted by culture’s objects. The thesis and the artworks that form this PhD submission employ examples of cinema from the early 1970s onwards to affectively map how the spectral, but impactful, reign of the derivative has taken hold, and how its violent rearranging of time and space is dramatically different from the commodity form’s sedimenting of the same forces. I examine how the modern derivative’s ability to bundle and unbundle the component qualities of a commodity, and then mine the information arising from those actions, performs a spectral, politically romantic, but absolute power. I consider how the function of probability for both derivatives and information engineering has amplified the ideological effects of the derivative and afforded it the qualities of a mythic law. Cinema is employed throughout as a form of divination that locates instances where the ideological info-power of the derivative clashes most visibly and productively with the chaotic and material properties of information. I suggest that it is in these shuddering bodies and markers of underlying dispositions of power that the refracted, immense power and mythic law of the derivative can be represented and annulled.
Spin-orbit-induced longitudinal spin-polarized currents in nonmagnetic solids
Creators: name: Wimmer, Sebastian
name: Seemann, M.
name: Chadova, Kristina
name: Koedderitzsch, Diemo
name: Ebert, Hubert
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: 530 Physik
subject: 72.25.Ba, 61.50.Ah, 71.15.Rf, 72.15.Qm

description: For certain nonmagnetic solids with low symmetry the occurrence of spin-polarized longitudinal currents is predicted. These arise due to an interplay of spin-orbit interaction and the particular crystal symmetry. This result is derived using a group-theoretical scheme that allows investigating the symmetry properties of any linear response tensor relevant to the field of spintronics. For the spin conductivity tensor it is shown that only the magnetic Laue group has to be considered in this context.Within the introduced general scheme also the spin Hall and additional related transverse effects emerge without making reference to the two-current model. Numerical studies confirm these findings and demonstrate for (Au1−xPtx )4Sc that the longitudinal spin conductivity may be on the same order of magnitude as the conventional transverse one. The presented formalism only relies on the magnetic space group and therefore is universally applicable to any type of magnetic order.
Bit-Interleaved Coded Multiple Beamforming with Perfect Coding
Creators: name: Li, Boyu
name: Ayanoglu, Ender
Publisher: name: arXiv
Year: 2010
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: When the Channel State Information (CSI) is known by both the transmitter and the receiver, beamforming techniques employing Singular Value Decomposition (SVD) are commonly used in Multiple-Input Multiple-Output (MIMO) systems. Without channel coding, there is a trade-off between full diversity and full multiplexing. When channel coding is added, both of them can be achieved as long as the code rate Rc and the number of employed subchannels S satisfy the condition RcS<=1. By adding a properly designed constellation precoder, both full diversity and full multiplexing can be achieved for both uncoded and coded systems with the trade-off of a higher decoding complexity, e.g., Fully Precoded Multiple Beamforming (FPMB) and Bit-Interleaved Coded Multiple Beamforming with Full Precoding (BICMB-FP) without the condition RcS<=1. Recently discovered Perfect Space-Time Block Code (PSTBC) is a full-rate full-diversity space-time code, which achieves efficient shaping and high coding gain for MIMO systems. In this paper, a new technique, Bit-Interleaved Coded Multiple Beamforming with Perfect Coding (BICMB-PC), is introduced. BICMB-PC transmits PSTBCs through convolutional coded SVD systems. Similar to BICMB-FP, BICMB-PC achieves both full diversity and full multiplexing, and its performance is almost the same as BICMB-FP. The advantage of BICMB-PC is that it can provide a much lower decoding complexity than BICMB-FP, since the real and imaginary parts of the received signal can be separated for BICMB-PC of dimensions 2 and 4, and only the part corresponding to the coded bit is required to acquire one bit metric for the Viterbi decoder.
description: accepted to conference; Proc. IEEE ICC 2012
A relation between screening masses and real-time rates
Creators: name: Brandt, Bastian B.
name: Francis, A.
name: Laine, M.
name: Meyer, H. B.
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: Thermal Field Theory, Quark-Gluon Plasma, Resummation, Lattice QCD
subject: 530 Physik

description: Thermal screening masses related to the conserved vector current are determined for the case that the current carries a non-zero Matsubara frequency, both in a weak-coupling approach and through lattice QCD. We point out that such screening masses are sensitive to the same infrared physics as light-cone real-time rates. In particular, on the perturbative side, the inhomogeneous Schrödinger equation determining screening correlators is shown to have the same general form as the equation implementing LPM resummation for the soft-dilepton and photon production rates from a hot QCD plasma. The static potential appearing in the equation is identical to that whose soft part has been determined up to NLO and on the lattice in the context of jet quenching. Numerical results based on this potential suggest that screening masses overshoot the free results (multiples of 2 πT ) more strongly than at zero Matsubara frequency. Four-dimensional lattice simulations in two-flavour QCD at temperatures of 250 and 340 MeV confirm the non-static screening masses at the 10% level. Overall our results lend support to studies of jet quenching based on the same potential at T ≳ 250 MeV.
description: SCOAP3
AtlantOS fitness for HAB Bulletins
Creators: name: Cusack, Caroline
name: Ruiz-Villarreal, Manuel
name: Eikrem, Wenche
name: Dale, Trine
name: Maguire, Julie
name: Dabrowski, Tomasz
name: Ledang, Anna B.
name: McElligott, Dee
name: Moejes, Fiona
name: Silke, Joe
Publisher: name: AtlantOS
Year: 2019

description: Assessment of the observing system fitness for HAB warning bulletin in the Atlantic
Searching for comets on the World Wide Web: The orbit of 17P/Holmes from the behavior of photographers
Creators: name: Lang, Dustin
name: Hogg, David W.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We performed an image search for "Comet Holmes," using the Yahoo Web search engine, on 2010 April 1. Thousands of images were returned. We astrometrically calibrated---and therefore vetted---the images using the Astrometry.net system. The calibrated image pointings form a set of data points to which we can fit a test-particle orbit in the Solar System, marginalizing over image dates and detecting outliers. The approach is Bayesian and the model is, in essence, a model of how comet astrophotographers point their instruments. In this work, we do not measure the position of the comet within each image, but rather use the celestial position of the whole image to infer the orbit. We find very strong probabilistic constraints on the orbit, although slightly off the JPL ephemeris, probably due to limitations of our model. Hyperparameters of the model constrain the reliability of date meta-data and where in the image astrophotographers place the comet; we find that ~70 percent of the meta-data are correct and that the comet typically appears in the central third of the image footprint. This project demonstrates that discoveries and measurements can be made using data of extreme heterogeneity and unknown provenance. As the size and diversity of astronomical data sets continues to grow, approaches like ours will become more essential. This project also demonstrates that the Web is an enormous repository of astronomical information; and that if an object has been given a name and photographed thousands of times by observers who post their images on the Web, we can (re-)discover it and infer its dynamical properties.
description: As published. Changes in v2: data-driven initialization rather than JPL; added figures; clarified text
Lattice QCD Study for Gluon Propagator and Gluon Spectral Function
Creators: name: Suganuma, Hideo
name: Iritani, Takumi
name: Yamamoto, Arata
name: Iida, Hideaki
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the gluon propagator in the Landau gauge in SU(3) lattice QCD at $β$=5.7, 5.8 and 6.0 at the quenched level. The Euclidean Landau-gauge gluon propagator $D(r)\equiv D_{μμ}^{aa}(x)/24$ is found to be well described by four-dimensional Yukawa-type function $e^{-mr}/r$ in the infrared and intermediate region of $r \equiv (x_μx_μ)^{1/2}$ = 0.1 $\sim$ 1.0fm. The infrared effective gluon mass is obtained as $m \simeq$ 600MeV. Associated with the 4D Yukawa-type gluon propagator, we derive analytical expressions for the zero-spatial-momentum propagator $D_0(t)$, the effective mass $M_{\rm eff}(t)$, and the spectral function $ρ(ω)$ of the gluon field. Remarkably, the obtained gluon spectral function $ρ(ω)$ is almost negative definite, except for a positive $δ$-functional peak at $ω=m$. Since the Yukawa-type propagation indicates a three-dimensional space-time character, we consider a hypothesis of an effective dimensional reduction by generalized Parisi-Sourlas mechanism in a stochastic color-magnetic vacuum of infrared QCD.
Skew scattering in dilute ferromagnetic alloys
Creators: name: Zimmermann, Bernd
name: Chadova, Kristina
name: Koedderitzsch, Diemo
name: Bluegel, Stefan
name: Ebert, Hubert
name: Fedorov, Dmitry V.
name: Long, Ngyuen H.
name: Mavropoulos, Phivos
name: Mertig, Ingrid
name: Mokrousov, Yuriy
name: Grandhand, Martin
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: 530 Physik
subject: 72.25.Ba, 71.15.Rf, 75.76.+j, 85.75.−d

description: The challenging problem of skew scattering for Hall effects in dilute ferromagnetic alloys, with intertwined effects of spin-orbit coupling, magnetism, and impurity scattering, is studied here from first principles. Our main aim is to identify chemical trends and work out simple rules for large skew scattering in terms of the impurity and host states at the Fermi surface, with particular emphasis on the interplay of the spin and anomalous Hall effects in one and the same system. The predicted trends are benchmarked by referring to three different ab initio methods based on different approximations with respect to the electronic structure and transport properties.
Beta Pictoris and AB Doradus Moving Groups: Likely New Low-Mass Members
Creators: name: Schlieder, Joshua E.
name: Lépine, Sébastien
name: Simon, Michal
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present results from our continuing program to identify new, low-mass, members of the nearby young moving groups (NYMGs) using a proper motion selection algorithm and various observational techniques. We have three goals: 1) To provide high priority targets for exoplanet searches by direct imaging, 2) To complete the census of the membership in the NYMGs down to ~0.1 Msun, and thus 3) Provide a well-characterized sample of nearby (median distances at least twice as close as the Taurus and Ophiuchus SFR's), young (8-50 Myr) stars for detailed study of their physical properties and multiplicity. Our program proceeds as follows: we apply the selection algorithm to a proper motion catalog where initial selection cuts of candidate members are based on the mean motion of known NYMG members and the proper motions and photometric distances of the candidates. NYMG membership is investigated further using possible signs of youth, including H-alpha emission and X-ray flux, and then verified through radial velocity (RV) measurements. We identify TYC 1766-1431-1 (M3), TYC 1208-468-1 and 2 (K3), TYC 7558-655-1 (K5), and PM I04439+3723W and E (M3) as likely members of the Beta Pictoris moving group (BPMG) and TYC 1741-2117-1N and S (K7), TYC 1752-63-1 (K7), TYC 523-573-1 (K7), and TYC 4943-192-1 (M0) as likely members of the AB Doradus moving group (ABDMG). We also rule out the membership of several BPMG and ABDMG candidates. To date our program has identified 16 new NYMG members of spectral type K3 or later.
description: 30 pages with 5 figures, accepted for publication in the Astronomical Journal
Spatial patterns of humidity, fuel moisture, and fire danger across a forested landscape
Creators: name: Van Der Kamp, Derek W.
Publisher: name: University of British Columbia
Year: 2017

description: Spatial variability in fuel moisture driven by changes in microclimate is an important bottom-up factor determining spatial wildfire behaviour, as fuel moisture impacts fire intensity, severity, and spread probability. However, few studies have examined how landscape scale patterns in near-surface microclimates impact fuel moisture patterns. This study quantified patterns of near-surface atmospheric conditions within a heterogeneous forested landscape, and determined how those patterns impact the spatial variability of fuel moisture and fire danger across the landscape. Observations across a forested landscape demonstrated that, in general, spatial variability in near-surface relative humidity and temperature was highest during dry, clear-sky conditions. However, daytime relative humidity was an exception, being relatively homogenous across the landscape and only weakly related to weather conditions. Canopy cover and above-canopy radiation load predicted a significant portion of the spatial patterns in relative humidity and temperature. Changes in canopy cover had the largest impact on near-surface conditions. Open sites saw higher relative humidity, on average, due to nocturnal longwave cooling. A novel fuel moisture model was presented that predicted between 76% and 93% of the variance in observations from independent sites or time periods, which is an improvement on a more complex model currently used operationally. This model was combined with meteorological observations to quantify spatial patterns in fuel moisture and potential fire danger across the landscape. Daytime fuel moisture and potential fire danger exhibited low spatial variability, regardless of weather conditions, and only 1-hour fuel moisture was related to canopy cover or radiation load. Fuel moisture and potential fire danger were more variable at night and that variability increased during cool, moist periods with low wind speeds. Patterns in fuel moisture and potential fire danger were dominated by differences in nocturnal longwave cooling due to changes in canopy cover. Open sites had lower daily mean potential fire danger. When fire danger was extrapolated over a larger study region, daytime conditions remained homogenous. Moreover, radiation load and canopy cover did not have a large enough direct influence on daytime fuel moisture to generate patches within the landscape that remain significantly wetter than the surrounding landscape.
Separation of the individual contributions to the spin Hall effect in dilute alloys within the first-principles Kubo-Středa approach
Creators: name: Chadova, Kristina
name: Fedorov, Dmitry V.
name: Herschbach, Christian
name: Gradhand, Martin
name: Mertig, Ingrid
name: Koedderitzsch, Diemo
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: 530 Physik
subject: 71.15.Rf, 72.25.Ba, 75.76.+j, 85.75.−d

description: We present a procedure for the separation of the intrinsic, side-jump, and skew-scattering contributions to the spin Hall conductivity within the ab initio Kubo-Středa approach. Furthermore, two distinct contributions to the side-jump mechanism, either independent of the vertex corrections or solely caused by them, are quantified as well. This allows for a detailed analysis of individual microscopic contributions to the spin Hall effect. The efficiency of the proposed method is demonstrated by a first-principles study of dilute metallic alloys based on Cu, Au, and Pt hosts.
Indonesian International Students in Australia during the COVID-19-Pandemic: Coming Out Stronger?
Creators: name: Missbach, Antje
name: Purdey, Jemma
Publisher: name: Advances in Southeast Asian Studies
Year: 2023

description: Australia is a sought-after destination for international students, including from countries of the Global South such as Indonesia. Prior to the pandemic, the tertiary education of international students was its second largest export. At the onset of the pandemic, Australia’s Prime Minister told international students they should return home immediately, warning them that they would not be supported by the government if they chose to stay. Throughout 2020 and 2021, Australian media outlets offered shocking reports and images of international students who had lost their homes and were queuing at soup kitchens. Experts feared that these images and the overall treatment of international students would do long-lasting damage not only to the education sector but also to Australia’s people-to-people relations overseas. In this article, we explore the destinies of postgraduate students from Indonesia during the pandemic in Australia. As Indonesia’s closest neighbor, Australia is the preferred destination for Indonesian students studying abroad and Australia has targeted Indonesia as a growth market in recent years. Based on qualitative interview data, we offer a picture of how this cohort of international students “muddled through” the pandemic. We ask what damage may have been done by the Australian government’s closure of its international borders and strict pandemic restrictions to its reputation as a welcoming country and center of educational excellence. What consequences might there be for this vital Indonesia–Australia relationship, in particular, and for the future of student and broader university engagement between the two countries? Our findings show a much more optimistic outlook than expected.
description: Advances in Southeast Asian Studies, ONLINE FIRST
Measurements of CO redshifts with Z-Spec for lensed submillimeter galaxies discovered in the H-ATLAS survey
Creators: name: Lupu, R. E.
name: Scott, K. S.
name: Aguirre, J. E.
name: Aretxaga, I.
name: Auld, R.
name: Barton, E.
name: Beelen, A.
name: Bertoldi, F.
name: Bock, J. J.
name: Bonfield, D.
name: Bradford, C. M.
name: Buttiglione, S.
name: Cava, A.
name: Clements, D. L.
name: Cooke, J.
name: Cooray, A.
name: Dannerbauer, H.
name: Dariush, A.
name: De Zotti, G.
name: Dunne, L.
name: Dye, S.
name: Eales, S.
name: Frayer, D.
name: Fritz, J.
name: Glenn, J.
name: Hughes, D. H.
name: Ibar, E.
name: Ivison, R. J.
name: Jarvis, M. J.
name: Kamenetzky, J.
name: Kim, S.
name: Lagache, G.
name: Leeuw, L.
name: Maddox, S.
name: Maloney, P. R.
name: Matsuhara, H.
name: Murphy, E. J.
name: Naylor, B. J.
name: Negrello, M.
name: Nguien, H.
name: Omont, A.
name: Pascale, E.
name: Pohlen, M.
name: Rigby, E.
name: Rodighiero, G.
name: Serjeant, S.
name: Smith, D.
name: Temi, P.
name: Thompson, M.
name: Valtchanov, I.
name: Verma, A.
name: Vieira, J. D.
name: Zmuidzinas, J.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present new observations from Z-Spec, a broadband 185-305 GHz spectrometer, of five sub-millimeter bright lensed sources selected from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) science demonstration phase (SDP) catalog. We construct a redshift finding algorithm using combinations of the signal-to-noise of all the lines falling in the Z-Spec bandpass to determine redshifts with high confidence, even in cases where the signal-to-noise in individual lines is low. We measure the dust continuum in all sources and secure CO redshifts for four out of five (z~1.5-3). In one source, SDP.17, we tentatively identify two independent redshifts and a water line, confirmed at z=2.308. Our sources have properties characteristic of dusty starburst galaxies, with magnification-corrected star formation rates of 10^(2-3) M_sun/yr. Lower limits for the dust masses (~a few 10^8 M_sun) and spatial extents (~1 kpc equivalent radius) are derived from the continuum spectral energy distributions, corresponding to dust temperatures between 54 and 69K. In the LTE approximation, we derive relatively low CO excitation temperatures (< 100 K) and optical depths (tau<1). Performing a non-LTE excitation analysis using RADEX, we find that the CO lines measured by Z-Spec (from J=4->3 to 10->9, depending on the galaxy) localize the best solutions to either a high-temperature / low-density region, or a low-temperature / high-density region near the LTE solution, with the optical depth varying accordingly. Observations of additional CO lines, CO(1-0) in particular, are needed to constrain the non-LTE models.
description: 28 pages, 15 figures, accepted for publication in ApJ, October 1, 2012, Issue 757 - 2
The conformal Yamabe constant of product manifolds
Creators: name: Ammann, Bernd
name: Dahl, Mattias
name: Humbert, Emmanuel
Publisher: name: arXiv
Year: 2011
Subjects: subject: Differential Geometry (math.DG)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35J60 (Primary) 35P30, 58J50, 58C40 (Secondary)

description: Let (V,g) and (W,h) be compact Riemannian manifolds of dimension at least 3. We derive a lower bound for the conformal Yamabe constant of the product manifold (V x W, g+h) in terms of the conformal Yamabe constants of (V,g) and (W,h).
description: 12 pages, to appear in Proc. AMS; v3: small changes, very last preprint version, close to published version