cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Time-dependent Stochastic Modeling of Solar Active Region Energy
Creators: name: Kanazir, M.
name: Wheatland, M. S.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Applications (stat.AP)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: A time-dependent model for the energy of a flaring solar active region is presented based on a stochastic jump-transition model (Wheatland and Glukhov 1998; Wheatland 2008; Wheatland 2009). The magnetic free energy of the model active region varies in time due to a prescribed (deterministic) rate of energy input and prescribed (random) flare jumps downwards in energy. The model has been shown to reproduce observed flare statistics, for specific time-independent choices for the energy input and flare transition rates. However, many solar active regions exhibit time variation in flare productivity, as exemplified by NOAA active region AR 11029 (Wheatland 2010). In this case a time-dependent model is needed. Time variation is incorporated for two cases: 1. a step change in the rates of flare jumps; and 2. a step change in the rate of energy supply to the system. Analytic arguments are presented describing the qualitative behavior of the system in the two cases. In each case the system adjusts by shifting to a new stationary state over a relaxation time which is estimated analytically. The new model retains flare-like event statistics. In each case the frequency-energy distribution is a power law for flare energies less than a time-dependent rollover set by the largest energy the system is likely to attain at a given time. For Case 1, the model exhibits a double exponential waiting-time distribution, corresponding to flaring at a constant mean rate during two intervals (before and after the step change), if the average energy of the system is large. For Case 2 the waiting-time distribution is a simple exponential, again provided the average energy of the system is large. Monte Carlo simulations of Case~1 are presented which confirm the analytic estimates. The simulation results provide a qualitative model for observed flare statistics in active region AR 11029.
description: 25 pages, 9 figures
Direction Dependence of Spin Relaxation in Confined 2D Systems
Creators: name: Wenk, Paul
name: Kettemann, Stefan
Publisher: name: arXiv
Year: 2010
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The dependence of spin relaxation on the direction of the quantum wire under Rashba and Dresselhaus (linear and cubic) spin orbit coupling is studied. Comprising the dimensional reduction of the wire in the diffusive regime, the lowest spin relaxation and dephasing rates for (001) and (110) systems are found. The analysis of spin relaxation reduction is then extended to non-diffusive wires where it is shown that, in contrast to the theory of dimensional crossover from weak localization to weak antilocalization in diffusive wires, the relaxation due to cubic Dresselhaus spin orbit coupling is reduced and the linear part shifted with the number of transverse channels.
description: 9 pages, 4 figures
Fragmentation inside an identified jet
Creators: name: Procura, Massimiliano
name: Stewart, Iain W.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Using Soft-Collinear Effective Theory we derive factorization formulae for semi-inclusive processes where a light hadron h fragments from a jet whose invariant mass is measured. Our analysis yields a novel "fragmenting jet function" G_i^h(s,z) that depends on the jet invariant mass \sqrt{s}, and on the fraction z of the large light-cone momentum components of the hadron and the parent parton i. We show that G_i^h(s,z) can be computed in terms of perturbatively calculable coefficients, J_{ij}(s,z/x), integrated against standard non-perturbative fragmentation functions, D_j^h(x). Our analysis yields a simple replacement rule that allows any factorization theorem depending on a jet function J_i to be converted to a semi-inclusive process with a fragmenting hadron h.
description: 3 pages; presented at "Quark Confinement and the Hadron Spectrum IX - QCHS IX" (30 August - 3 September 2010, Madrid, Spain), to appear in the proceedings
Phonon mode coupling and Fano-type antiresonance in polyethylene
Creators: name: Prettl, Wilhelm
name: Frank, W. F. X.
Publisher: name: Universität Regensburg
Year: 1979
Subjects: subject: 530 Physik

description: The decrease of the absorption strength of 73 cm–1 line in polyethylene and the strong antiresonance occuring above 310 K at the high frequency wing of the line are explained by assuming a Fanto type coupling between the 73 cm–1 phonon and a continuum of infrared active vibrational modes. The parameters determining the line shape are deduced from experimental absorption curves and conceivable coupling mechanisms are discussed.Die Abnahme der Absorption der 73 cm–1-Bande in Polyäthylen und die starke Antiresonanz, die oberhalb 310 K auf der hochfrequenten Seite der Bande einsetzt, werden erklärt durch Annahme einer Fano-Kopplung zwischen dem 73 cm–1-Phonon und einem Kontinuum von infrarot-aktiven Schwingungsmoden. Die Parameter, die die Linienform bestimmen, werden aus den experimentellen Absorptionskurven abgeleitet und Kopplungsmechanismen diskutiert.
Cooperative domain type interlayer $sp^3$-bond formation in graphite
Creators: name: Nishioka, Keita
name: Nasu, Keiichiro
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Using the classical molecular dynamics and the semiempirical Brenner's potential, we theoretically study the interlayer sigma bond formation, as cooperative and nonlinear phenomena induced by visible light excitations of a graphite crystal. We have found several cases, wherein the excitations of certain lattice sites result in new interlayer bonds even at non-excited sites. We have also found that, a new interlayer bond is easier to be formed around a bond, if it is already existing. As many more sites are going to be excited, the number of interlayer bonds increases nonlinearly with the number of excited sites. This nonlinearity shows 1.7 power of the total number of excited sites, corresponding to about three- or four-photon process.
description: 7 pages, 8 figures
Maltose excretion by the symbiotic Chlorella of the heliozoan Acanthocystis turfacea
Creators: name: Matzke, Bettina
name: Schwarzmeier, Elisabeth
name: Loos, Eckhard
Publisher: name: Universität Regensburg
Year: 1990
Subjects: subject: Chlorella (symbiosis) - Maltose excretion (Chlorella, symbiosis) - Symbiosis (Chlorella-Acanthocystis) - Transport, active
subject: 570 Biowissenschaften, Biologie

description: Chlorella sp. strain 3.83, a symbiotic Chlorella isolated from the heliozoan Acanthocystis turfacea, excreted between 8% and 16% of assimilated 14CO2 as maltose in the light (15000 lx), with a pH optimum around 4.8. This percentage increased when the illuminance was lowered (36% at 1700 lx). Release of [14C]maltose continued in darkness and could be inhibited by the uncoupler carbonyl cyanide p-trifluoro-methoxyphenylhydrazone and by diethylstilbestrol. Net efflux of maltose was observed even at a concentration ratio of extracellular/intracellular maltose of 7.8. Exogenous [*^C]maltose (5 mM) was taken up by the cells with a rate <2% of that of simultaneous maltose release, indicating a practically unidirectional transport. It is concluded that maltose excretion is an active-transport process.
An analysis of genetic variants associated with autism spectrum disorder
Creators: name: Callaghan, Daniel Benjamin
Publisher: name: University of British Columbia
Year: 2018

description: Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder affecting roughly 1% of the human population. Genomics research to date has discovered only a fraction of the variants causative for ASD. To this end, we whole-genome sequenced a cohort of 119 ASD individuals in order to find likely pathogenic variation. After quality and frequency filters, we prioritized variants as likely causal according to rarity and predicted damage scores (CADD and Snap2). Here, we report five de novo damaging variants and seven likely damaging variants of unknown inheritance. Since much of the variation reported in ASD cases is uncertain both in function and in significance in ASD, we aimed to functionally characterize missense variants from the ASD literature in PTEN and SYNGAP1, two well-characterized ASD genes. We curated missense variants of unknown significance from the ASD literature and assayed their functional effect in yeast using a Synthetic Genetic Array. We chose previously biochemically validated variants, population variants, and other variants in the genes of interest to gain insight into the functional diversity of PTEN and SYNGAP1 variation. We established functional effect of the ASD variants of unknown significance in PTEN and showed that computational predictors of damage are reasonable predictors of variants’ functional effects in yeast. We found that agreement of computational metrics breaks down when predicting damage in certain genes, such as SYNGAP1. Functionalizing variants in this way contributes to our understanding of the range of functional effects of ASD variants.
Cell wall-lytic activity in Chlorella fusca
Creators: name: Loos, Eckhard
name: Meindl, Doris
Publisher: name: Universität Regensburg
Year: 1984
Subjects: subject: Cell cycle - Cell wall (lysis) - Chlorella - beta-1,4-Mannanase
subject: 570 Biowissenschaften, Biologie

description: The soluble fraction of homogenates of synchronous Chlorella fusca was tested for carbohydrate-lyzing activities. With isolated cell walls and beta-1,4-mannan or carboxymethyl cellulose as substrates, a sharp increase in activity occurred shortly before release of the daughter cells followed by a decline during release. The lytic activities were partially purified by ammonium sulphate precipitation and analyzed by gel filtration on a calibrated column. Apparent molecular weights were 27,000 for cell wall autolysin(s) and beta-1,4-mannanase, 36,000 for carboxymethyl cellulase and gE70,000 for another beta-1,4-mannanase. Incubation of isolated cell walls with an enzyme preparation purified by ammonium sulphate precipitation resulted in release of up to 70% of the cell wall carbohydrate as monosaccharide, predominantly mannose and glucose. The carbohydrate released in vivo into the culture medium shortly before and during liberation of the daughter cells consisted largely of polymeric material with rhamnose, fucose and mannose as main constitutents. Upon poisoning the cells with NaN3 or carbonyl cyanide p-trifluoromethoxy-phenylhydrazone, however, a monosaccharide fraction consisting of mannose and glucose was predominant in the medium. It is suggested that the major products of cell wall lysis in vivo are monosaccharides which are rapidly taken up and metabolized by the developing daughter cells in an energy-dependent manner.
Composition of the cell wall of Chlorella fusca
Creators: name: Loos, Eckhard
name: Meindl, Doris
Publisher: name: Universität Regensburg
Year: 1982
Subjects: subject: Cell wall (composition); Chlorella
subject: 570 Biowissenschaften, Biologie

description: Isolated cell walls of mature Chlorella fusca consisted of about 80% carbohydrate, 7% protein, and 13% unidentified material. Mannose and glucose were present in a ratio of about 2.7:1 and accounted for most of the carbohydrate. Minor components were glucuronic acid, rhamnose, and traces of other sugars; galactose was absent. After treatment with 2 M trifluoroacetic acid or with 80% acetic acid/HNO3 (10/1, v/v), a residue with a mannose/glucose ratio of 0.3:1 was obtained, probably representing a structural polysaccharide. An X-ray diffraction diagram of the walls showed one diffuse reflection at 0.44 nm and no reflections characteristic of cellulose. Walls from young cells contained about 51% carbohydrate, 12% protein, and 37% unidentified material. Mannose and glucose were also the main sugars; their absolute amounts per wall increased 6–7 fold during cell growth. Walls isolated with omission of a dodecylsulphate/mercaptoethanol/urea extraction step had a higher protein content and, with young walls, a significantly higher glucose and fucose content. These data and other published cell wall analyses show a wide variability in cell wall composition of the members of the genus Chlorella.
Risk of progression of Carbapenemase-Producing-Enterobacteriaceae (CPE) colonization to infection by CPE genotype: a Singapore cohort study
Creators: name: Lo, Jamie J.
name: Kyaw Zaw Linn
name: Sengupta, Sharmila
name: Xiaowei, Huan
name: Tse Hsien Koh
name: Cherng, Benjamin Pei Zhi
name: Ang, Michelle
name: Partha Pratim De
name: Krishnan, Prabha Unny
name: Thean Yen Tan
name: Choon, Raymond Fong Kok
name: Pada, Surinder Kaur
name: Chan, Douglas
name: Say Tat Ooi
name: Deepak, Rama Narayana
name: Nares Smitasin
name: Sim, Nancy Tee Wen
name: Koh Cheng Thoon
name: Hsu, Li Yang
name: Lin, Raymond Tzer Pin
name: Teo, Jeanette W P
name: Oon Tek Ng
name: Indumathi Venkatachalam
name: Kalisvar Marimuthu
Publisher: name: F1000 Research Limited
Year: 2019

description: In the past decade, carbapenem-resistant Enterobacteriaceae (CRE) have emerged as a significant international public health threat1. Mechanisms of carbapenem resistance are typically divided into two main categories: 1) production of carbapenemase by carbapenemase-producing Enterobacteriaceae (CPE) and 2) β-lactamase activity combined with dysregulation of porin channels by non- carbapenemase-producing carbapenem-resistant Enterobacteriaceae (NCPCRE)1,2. Among CPE, there are various carbapenemase genes such as KPC, OXA, NDM, VIM, IMP, and IMI.
Progression of CRE colonization to infection has been described before. However, the analysis of the progression from CPE colonization to infection by carbapenemase genotype as well as CPE species has not been studied. In this study, we examined the following:	Risk of carbapenemase genotype-matchedprogression from colonization to infection for KPC, NDM, OXA, IMI, and IMP carbapenemase producing Enterobacteriaceae (CPE) compared to non- carbapenemase-producing carbapenem-resistant Enterobacteriaceae (NCPCRE)	Risk of carbapenemase genotype and species- matched progression from colonization to infection for each CPE genotype compared to NCPCRE.
Negative FIR-photoconductivity in n-GaAs
Creators: name: Heisel, W.
name: Böhm, W.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1981
Subjects: subject: semiconductors - epitaxial GaAs - far-infrared magnetospectroscopy - impact inonization - photoconductivity
subject: 530 Physik

description: Negative photoconductivity in n-GaAs has been observed in the far infrared spectral range between 20 and 29 cm–1. Negative photoconductivity occurs when a magnetic field is applied to the samples and impact ionization of shallow donors by the electric bias field is the dominant mechanism of electron excitation to the conduction band. A conceivable model qualitatively explaining the experimental results is proposed, which involves optical transitions from the lowest Landau subband to higher bound states of shallow donors.
Cell wall composition of chlorococcal algae
Creators: name: Blumreisinger, Maria
name: Meindl, Doris
name: Loos, Eckhard
Publisher: name: Universität Regensburg
Year: 1983
Subjects: subject: Chlorococcal algae; cell wall composition
subject: 570 Biowissenschaften, Biologie

description: The cell walls of representatives of the genera Chlorella, Monoraphidium, Ankistrodesmus and Scenedesmus contained 24–74% neutral sugars, 1–24% uronic acids, 2–16% protein and 0–15% glucosamine. Two types of cell walls could be discerned containing as main sugars either rhamnose and galactose or mannose and glucose with a lack of galactose.
Far-Infrared Two-Photon Transitions in n-GaAs
Creators: name: Böhm, W.
name: Ettlinger, E.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1981
Subjects: subject: 530 Physik
subject: 32.80.Kf, 72.40.+w, 76.40.+b, 78.20.Ls

description: Two-photon transitions in the far-infrared spectral range have been observed for the first time. The magnetophotoconductivity of n-GaAs measured by a pulsed high-power CH3F molecular laser at λ=496 μm exhibited two-photon transitions between 1s and 2s shallow donor states and two-photon cyclotron resonance. The experimental results and symmetry considerations indicate that the observed two-photon cyclotron resonance is caused by impurities.
High‐speed photoconductivity and infrared to visible up‐conversion in GaP light‐emitting diodes
Creators: name: Moser, K.
name: Eisfeld, W.
name: Werling, U.
name: Wahl, S.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1984
Subjects: subject: GALLIUM PHOSPHIDES, HOLES, RECOMBINATION, PHOTOCONDUCTIVITY, ELECTROLUMINESCENCE, LIGHT EMITTING DIODES, ZINC, TELLURIUM, LIQUID PHASE EPITAXY, LASER RADIATION, IMAGE FORMING, INFRARED RADIATION, VISIBLE RADIATION, IMPURITIES, PHOTOIONIZATION
subject: 530 Physik
subject: 72.40.+w; 72.20.Jv; 85.60.Jb; 78.60.Fi

description: In GaP:N (Zn,Te) light‐emitting diodes extrinsic photoconductivity and infrared to visible up‐conversion have been investigated by short laser pulses at 10‐μm wavelength. A time constant of the order of 1 ns was observed indicating that free infrared excited hole to bound donor recombination yields the fast response.
Decay of the red Cu-S pair luminescence in GaP
Creators: name: Moser, K.
name: Baumgartner, R.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1984
Subjects: subject: 530 Physik

description: The red Cu-S pair luminescence in GaP has been studied by time resolved spectroscopy at several photon energies between 1.39 and 1.77 eV for times shorter than 40 μs. Superimposed on a long lasting luminescence a fast decay was observed showing the typical behaviour of donor-acceptor (DA) pair recombination. The transition probability Wm was estimated to be 106 s-1, being of the same order of magnitude as that of the other known DA pairs in GaP.
Optical bistability in InSb at room temperature with two‐photon excitation
Creators: name: Kar, A. K.
name: Mathew, J. G. H.
name: Smith, S. D.
name: Davis, D.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1983
Subjects: subject: indium antimonides, medium temperature, photons, excitation, experimental data, infrared radiation, resonators, nonlinear optics, refraction, absorption, radiations, oscillation modes, pulses, carbon dioxide lasers, tuning, optical bistability, laser cavities
subject: 530 Physik
subject: 42.50.Md; 85.60.-q; 42.60.Fc

description: We report the observation of optical bistability in an InSb resonator at room temperature. This effect and fringe shifts were caused by nonlinear refraction induced by two‐photon absorption of radiation from a single longitudinal mode injection‐locked pulsed CO2 laser operating at 9.6–10.6 μm. Intensities as low as 100 kW/cm2 were found to be sufficient to tune the 250‐μm‐thick cavity through a fringe maximum. From our results we deduce a value of χ(3) of the order of 10−4 esu over the range of intensities investigated.
Infrared spectral distribution of photoconductivity and up‐conversion in GaP light emitting diodes
Creators: name: Moser, K.
name: Wahl, S.
name: Eisfeld, W.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1985
Subjects: subject: PHOTOCONDUCTIVITY, INFRARED SPECTRA, GALLIUM ARSENIDES, ELECTROLUMINESCENCE, BINDING ENERGY, DONORS, QUANTUM EFFICIENCY, LIGHT EMITTING DIODES
subject: 530 Physik
subject: 72.40.+w; 78.40.Fy; 78.60.Fi; 85.60.Dw

description: The spectral distribution of photoconductivity and infrared excited electroluminescence has been determined in GaP light emitting diodes at low temperatures by conventional infrared spectroscopic techniques. The observed photoresponse was found to be caused by ionization of shallow donors only, showing a peak sensitivity of 20 mA/W at 13‐μm wavelength. Spectral structures for photon energies lower than the binding energies of shallow donors are attributed to electric field assisted photoionization. An external quantum efficiency of 3×10−3 was obtained being largely independent on the bias voltage and the wavelength of infrared stimulation.
Saturation behavior of extrinsic photoconductivity in GaP light emitting diodes at high infrared intensities
Creators: name: Moser, K.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1986
Subjects: subject: GaP light emitting diodes - ir-detection - saturation - response time
subject: 530 Physik

description: Saturation of extrinsic photoconductivity in GaP:N(Zn, Te) diodes could be achieved by excitation with a TEA-CO2-laser. At wavelengths in the 10 mgrm range intensities of several 100 kW/cm2 being near the damage threshold were applied. Carrier lifetimes of 60 ps at 4.2 K and 200 ps at 77 K could be estimated. The only conceivable mechanism explaining these short time constants is the capture of infrared excited holes by ionized shallow acceptors in the highly compensated p-side of the diode.
Far-infrared two-photon intraband transitions in n-InSb
Creators: name: Dirnhofer, P.
name: Böhm, W.
name: Prettl, Wilhelm
name: Rössler, Ulrich
Publisher: name: Universität Regensburg
Year: 1985
Subjects: subject: 530 Physik

description: Two-photon cyclotron resonance and two-photon shallow donor transitions have been excited by a high power pulsed D2O laser emitting λ = 119 μm and 66 μm laser lines at the same time. Transitions involving the absorption of two 119 μm photons or simultaneously one 119 μm and one 66 μm photon were observed. Two-photon selection rules are discussed by a rigorous treatment of the symmetry of the free electron Hamiltonian.
Non-canonical activation of Hedgehog signaling in prostate cancer cells is mediated by the interaction of Gli proteins and transcriptionally active androgen receptor
Creators: name: Truong, Sarah
Publisher: name: University of British Columbia
Year: 2017

description: The Hedgehog (Hh) pathway is an embryonic development pathway, driven by peptide ligands called hedgehogs. During progression of prostate cancer (PCa), Hh signaling is increased, with especially high activation in castration resistant disease (CRPC). Evidence is lacking for canonical Hh signaling in PCa, indicating the likelihood that non-canonical pathways are involved. Our work shows that transcriptionally active androgen receptor (AR) binding to Gli proteins drives non-canonical Hh signaling in PCa. Androgen-sensitive LNCaP and androgen-independent LNCaP-AI and LN95 cells were transfected with a Gli-promoter driven luciferase reporter and treated with R1881, enzalutamide, or both, and luciferase activity was measured. Androgen treatment (R1881) induced Gli transcriptional activity while enzalutamide reversed this effect. Similarly, siRNA knockdown of full-length AR (AR-FL) suppressed R1881-induced Gli transcription. Western blot and qPCR confirmed increased expression of endogenous Gli target genes Gli1 and Ptch1 with androgen treatment. Androgen treatment stabilized expression of full-length active Gli3 in a dose-dependent manner but this was reversed by AR knockdown using siRNA. AR binds to Gli3 at the protein processing domain (PPD), which, given the above data, suggests that AR binding to Gli stabilizes full-length Gli3 by preventing phosphorylation and ubiquitination of the PPD, thereby stopping proteolytic cleavage and proteosomal degradation from occurring. Finally, we found that an AR-binding decoy peptide derived from the Gli2 C-terminus can compete with Gli3 for binding to AR, suppressing Gli transcriptional activity in PCa cells. Our data supports the idea that transcriptionally active AR binding to Gli proteins provides a means for Hh signaling to occur. Not only does AR co-activate Gli transcriptional activity, but it also alters the proteolytic processing of Gli proteins by preventing phosphorylation and ubiquitination of the Gli PPD by competing with β-TrCP for binding to Gli. Collectively, our findings show the importance of AR-Gli interaction in PCa progression.
Eccentricity Trap: Trapping of Resonantly Interacting Planets near the Disk Inner Edge
Creators: name: Ogihara, Masahiro
name: Duncan, Martin J.
name: Ida, Shigeru
Publisher: name: arXiv
Year: 2010
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Using orbital integration and analytical arguments, we have found a new mechanism (an "eccentricity trap") to halt type I migration of planets near the inner edge of a protoplanetary disk. Because asymmetric eccentricity damping due to disk-planet interaction on the innermost planet at the disk edge plays a crucial role in the trap, this mechanism requires continuous eccentricity excitation and hence works for a resonantly interacting convoy of planets. This trap is so strong that the edge torque exerted on the innermost planet can completely halt type I migrations of many outer planets through mutual resonant perturbations. Consequently, the convoy stays outside the disk edge, as a whole. We have derived semi-analytical formula for the condition for the eccentricity trap and predict how many planets are likely to be trapped. We found that several planets or more should be trapped by this mechanism in protoplanetary disks that have cavities. It can be responsible for the formation of non-resonant, multiple, close-in super-Earth systems extending beyond 0.1AU. Such systems are being revealed by radial velocity observations to be quite common around solar-type stars.
description: 24 pages, 7 figures, accepted for publication in ApJ
Electromagnetic properties of baryons
Creators: name: Ledwig, T.
name: Martin-Camalich, J.
name: Pascalutsa, V.
name: Vanderhaeghen, M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We discuss the chiral behavior of nucleon and Delta(1232) electromagnetic properties within the framework of a SU(2) covariant baryon chiral perturbation theory. Our one-loop calculation is complete to the order p^3 and p^4/Delta with Delta as the Delta(1232)-nucleon energy gap. We show that the magnetic moment of a resonance can be defined through the linear energy shift only when an additional relation between the involved masses and the applied magnetic field strength is fulfilled. Singularities and cusps in the pion mass dependence of the Delta(1232) electromagnetic moments reflect a non-fulfillment. We show results for the pion mass dependence of the nucleon iso-vector electromagnetic quantities and present results for finite volume effects on the iso-vector anomalous magnetic moment.
description: 4 pages, 3 figures, prepared for Proceedings of the International Conference on the Structure of Baryons (BARYONS'10), Osaka, Japan, Dec. 7-11, 2010
Wide field polarimetry around the Perseus cluster at 350 MHz
Creators: name: Brentjens, M. A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: This paper investigates the fascinating diffuse polarization structures at 350 MHz that have previously been tentatively attributed to the Perseus cluster and, more specifically, tries to find out whether the structures are located at (or near) the Perseus cluster, or in the Milky Way. A wide field, eight point Westerbork Synthesis Radio Telescope mosaic of the area around the Perseus cluster was observed in full polarization. The frequency range was 324 to 378 MHz and the resolution of the polarization maps was 2'x3'. The maps were processed using Faraday rotation measure synthesis to counter bandwidth depolarization. The RM-cube covers Faraday depths of -384 to +381 rad m^{-2} in steps of 3 rad m^{-2}. There is emission all over the field at Faraday depths between -50 and +100 rad m^{-2}. All previously observed structures were detected. However, no compelling evidence was found supporting association of those structures with either the Perseus cluster or large scale structure formation gas flows in the Perseus-Pisces super cluster. On the contrary, one of the structures is clearly associated with a Galactic depolarization canal at 1.41 GHz. Another large structure in polarized intensity, as well as Faraday depth at a Faraday depth of +30 rad m^{-2}, coincides with a dark object in WHAM H-alpha maps at a kinematic distance of 0.5 \pm 0.5 kpc. All diffuse polarized emission at 350 MHz towards the Perseus cluster is most likely located within 1 kpc from the Sun. The layers that emit the polarized radiation are less than 40 pc/B|| thick.
description: 16 pages, accepted for publication in A&A
Orientifolded Locally AdS3 Geometries
Creators: name: Loran, F.
name: Sheikh-Jabbari, M. M.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Continuing the analysis of [arXiv:1003.4089[hep-th]], we classify all locally AdS3 stationary axi-symmetric unorientable solutions to AdS3 Einstein gravity and show that they are obtained by applying certain orientifold projection on AdS3, BTZ or AdS3 self-dual orbifold, respectively O-AdS3, O-BTZ and O-SDO geometries. Depending on the orientifold fixed surface, the O-surface, which is either a space-like 2D plane or cylinder, or a light-like 2D plane or cylinder one can distinguish four distinct cases. For the space-like orientifold plane or cylinder cases these geometries solve AdS3 Einstein equations and are hence locally AdS3 everywhere except at the O-surface, where there is a delta-function source. For the light-like cases the geometry is a solution to Einstein equations even at the O-surface. We discuss the causal structure for static, extremal and general rotating O-BTZ and O-SDO cases as well as the geodesic motion on these geometries. We also discuss orientifolding Poincare patch AdS3 and AdS2 geometries as a way to geodesic completion of these spaces and comment on the 2D CFT dual to the O-geometries.
description: 26 page, 4 .eps figures
Division of the Energy and of the Momentum of Electromagnetic Waves in Linear Media into Electromagnetic and Material Parts
Creators: name: Saldanha, Pablo L.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We defend a natural division of the energy density, energy flux and momentum density of electromagnetic waves in linear media in electromagnetic and material parts. In this division, the electromagnetic part of these quantities have the same form as in vacuum when written in terms of the macroscopic electric and magnetic fields, the material momentum is calculated directly from the Lorentz force that acts on the charges of the medium, the material energy is the sum of the kinetic and potential energies of the charges of the medium and the material energy flux results from the interaction of the electric field with the magnetized medium. We present reasonable models for linear dispersive non-absorptive dielectric and magnetic media that agree with this division. We also argue that the electromagnetic momentum of our division can be associated with the electromagnetic relativistic momentum, inspired on the recent work of Barnett [Phys. Rev. Lett. 104, 070401 (2010)] that showed that the Abraham momentum is associated with the kinetic momentum and the Minkowski momentum is associated with the canonical momentum.
description: 6 pages, 1 figure
Interband excitation induced absorption by deep impurities in GaP
Creators: name: Moser, K.
name: Baumgartner, R.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1984
Subjects: subject: 530 Physik

description: Transient optical absorption at energies below the band gap in GaP crystals following pulsed interband excitation was observed. The additional absorption attained its maximum about 25 μsec after the excitation pulse and lasted about 100 μsec. The spectral dependence of the rise time and decay time of the absorption and that of the induced optical cross section were determined. The results suggest that the induced absorption is caused by several deep impurity levels, which are most probably due to Cu, being populated by the recombination of excited electrons.
Cyclotron-Resonance-Induced Nonequilibrium Phase Transition in n-GaAs
Creators: name: Weispfenning, M.
name: Hoeser, I.
name: Böhm, W.
name: Prettl, Wilhelm
name: Schöll, E.
Publisher: name: Universität Regensburg
Year: 1985
Subjects: subject: 530 Physik
subject: 72.20.Jv, 76.40.+b

description: A thresholdlike behavior of the far-infrared photoconductivity due to cyclotron resonance and a drastic deviation of the cyclotron-resonance line shape from a Lorentzian has been observed in n-GaAs at low temperatures by applying a high-power cw far-infrared laser. Both effects may consistently be explained in terms of generation-recombination-induced nonequilibrium phase transitions showing that, besides impact ionization of impurities, cyclotron resonance can critically control the conductivity of the semiconductors.
High-speed infrared-to-visible up-conversion by free-to-bound transitions in GaP light emitting diodes
Creators: name: Moser, K.
name: Eisfeld, W.
name: Penzenstadler, W.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1985
Subjects: subject: Electronics and devices; Optics, quantum optics and lasers
subject: 530 Physik
subject: 85.60.Jb; 42.65.Ky

description: In GaP:N (Zn,Te) light emitting diodes electroluminescence and photoluminescence have been excited at 4.2K by a Q-switched CO2 laser and a pulsed N2 laser, respectively. In the luminescence spectral transitions of free holes to bound donor states could be identified, being responsible for the fast radiative decay on a nanosecond timescale.
Raman optical activity and stimulated Raman scattering along the c axis in α-quartz
Creators: name: Klein, M.
name: Maier, Max
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1983
Subjects: subject: 530 Physik

description: Stimulated Raman scattering of the 132- and 468-cm-1 optical lattice vibrations was investigated along the c axis (z direction) of α-quartz. We measured the dependence of the Raman threshold intensity on the polarization of the neodymium-doped yttrium aluminum garnet (Nd: YAG) laser pump light and on temperature from 10 to 70 K. The polarization of the stimulated Raman Stokes light was determined for different pump light polarizations. Raman optical activity was observed for the 132-cm-1 mode of α-quartz. In a right-handed, optically active quartz crystal the Raman threshold intensity for left-handed, circularly polarized pump light was lower by a factor of about 1.5 than for right-handed circularly polarized light. Raman optical activity was not observed for the 468-cm-1 mode within our experimental accuracy. A theory of stimulated Raman scattering including the effects of Raman optical activity is applied to quartz. Relations between the Raman circular intensity difference and the magnetic dipole and electric quadrupole polarizabilities are derived. The experimental results for both Raman modes are compared with a traveling wave and an oscillator theory of stimulated Raman scattering.
Nonlinear Far-Infrared Magnetoabsorption and Optically Detected Magnetoimpurity Effect in n-GaAs
Creators: name: Pidgeon, C.
name: Vass, A.
name: Allan, G. R.
name: Prettl, Wilhelm
name: Eaves, L.
Publisher: name: Universität Regensburg
Year: 1983
Subjects: subject: 530 Physik
subject: 78.50.Ge, 42.65.Gv, 78.20.Ls

description: Measurements have been made of cw nonlinear far-infrared magnetoabsorption in pure, partially compensated n-GaAs. A new optical observation of the magnetoimpurity resonance has been demonstrated. Analysis in terms of a three-level model gives effective lifetimes of ∼0.5 μs "off resonance" and 30 ns "on resonance," implying the possibility of laser action in the former case.
Photoconductive infrared excitation spectrum of GaP diode wafers and application as an infrared imaging system
Creators: name: Moser, K.
name: Brechter, M.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1987
Subjects: subject: 530 Physik

description: The photoconductive excitation spectrum of GaP:N (ZnTe) diodes was measured irradiating the samples from p- and n-side unter forward and reverse bias conditions. The ionization thresholds of S and Te donors as well as transitions from their ground states to excited bound levels with subsequent ionization by the electric field could be seen. The observed minima in the continuum above the ionization threshold are due to phonon assisted fast recombination. The photoconductive signal by irradiation from the p-side is greater and sets on at lower photon energies. In addition, the transmission spectrum was also investigated and interpreted. The green photoluminescence resulting from the recombination of infrared generated carriers in the pn-junction can be applied for infrared imaging if GaP diode wafers of suitable size are employed.
Targeting and efficacy of novel mab806-antibody-drug conjugates in malignant mesothelioma
Creators: name: Chia, PL
name: Parakh, Sagun
name: Tsao, MS
name: Pham, NA
name: Gan, Hui
name: Cao, D
name: Burvenich, Ingrid
name: Rigopoulos, Angela
name: Reilly, EB
name: John, Thomas
name: Scott, Andrew
Publisher: name: La Trobe
Year: 2023
Subjects: classificationCode: 3202
subject: Clinical sciences
classificationCode: 3211
subject: Oncology and carcinogenesis

description: © 2020 by the authors. Licensee MDPI, Basel, Switzerland. Epidermal growth factor receptor (EGFR) is highly overexpressed in malignant mesothelioma (MM). MAb806 is a novel anti-EGFR antibody that selectively targets a tumor-selective epitope. MAb806-derived antibody drug conjugates (ADCs), ABT-414, ABBV-221 and ABBV-322, may represent a novel therapeutic strategy in MM. EGFR and mAb806 epitope expressions in mesothelioma cell lines were evaluated using an array of binding assays, and the in vitro cell effects of ABT-414 and ABBV-322 were determined. In vivo therapy studies were conducted in mesothelioma xenograft and patient-derived xenograft (PDX) tumor models. We also performed biodistribution and imaging studies to allow the quantitative targeting of MM by mAb806 using a89Zr-labeled immunoconjugate—ch806. A high EGFR expression was present in all mesothelioma cell lines evaluated and mAb806 binding present in all cell lines, except NCIH-2452. ABT-414 and ABBV-322 resulted in significant tumor growth inhibition in MM models with high EGFR and mAb806 epitope expressions. In contrast, in an EGFR-expressing PDX model that was negative for the mAb806 epitope, no growth inhibition was observed. We demonstrated the specific targeting of the mAb806 epitope expressing MM tumors using89Zr-based PET imaging. Our data suggest that targeting EGFR in MM using specific ADCs is a valid therapeutic strategy and supports further investigation of the mAb806 epitope expression as a predictive biomarker.
Infrared to visible up‐conversion using GaP light‐emitting diodes
Creators: name: Eisfeld, W.
name: Werling, U.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1983
Subjects: subject: gallium phosphides, light emitting diodes, frequency converters, infrared radiation, visible radiation, experimental data, electroluminescence, excitation, carbon dioxide lasers, quantum efficiency, photomultipliers, noise, thermal radiation, background radiation
subject: 530 Physik
subject: 42.65.Dr; 42.65.Es; 42.65.Ky; 85.60.Dw

description: Electroluminescence excited by infrared radiation has been observed in GaP light‐emitting diodes (LED’s) at low temperatures providing a new efficient method to convert infrared radiation within a broad spectral range into visible light. Using 10.6‐μm radiation of a CO2 laser an up‐conversion quantum efficiency of 3.4×10−6 was found. If a low dark current photomultiplier is employed to detect the LED emission the dominant noise source is due to conversion of thermal background radiation yielding a noise equivalent power of NEP=1.6×10−9 W/Hz1/2.
Grand Unification in Neutron Stars
Creators: name: Kaspi, Victoria M.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The last decade has shown us that the observational properties of neutron stars are remarkably diverse. From magnetars to rotating radio transients, from radio pulsars to `isolated neutron stars,' from central compact objects to millisecond pulsars, observational manifestations of neutron stars are surprisingly varied, with most properties totally unpredicted. The challenge is to establish an overarching physical theory of neutron stars and their birth properties that can explain this great diversity. Here I survey the disparate neutron stars classes, describe their properties, and highlight results made possible by the Chandra X-ray Observatory, in celebration of its tenth anniversary. Finally, I describe the current status of efforts at physical `grand unification' of this wealth of observational phenomena, and comment on possibilities for Chandra's next decade in this field.
description: Published in Proceedings of the National Academy of Sciences special issue in celebration of Chandra's 10th Anniversary.
Oscillations and Chaotic Current Fluctuations in n-GaAs
Creators: name: Brandl, A.
name: Geisel, T.
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 1987
Subjects: subject: 530 Physik
subject: 05.40
subject: 72.70
subject: 72.20J

description: Chaotic current fuctuations have been observed in the negative differential conductivity region of n-GaAs at 4.2 K under static external conditions. Power spectra, Poincaré sections and the fractal dimension of the attractor were determined as functions of the applied voltage for various magnetic-field strengths B. For B = 0 only limit cycles were observed. For B > 0 our results indicate successive Hopf bifurcations and a Ruelle-Takens-Newhouse transition to chaos and point to a crucial role of the magnetic field.
title: MIMICA V5.1, user guide
Creators: name: Savre, Julien
name: Brakebusch, Matthias
Publisher: name: Universitätsbibliothek der Ludwig-Maximilians-Universität München
Year: 2021

description: This document introduces the MISU-MIT Cloud and Aerosol (MIMICA) model, an atmospheric model dedicated to the simulation of clouds and other atmospheric processes at high resolution. The document contains a detailed description of the code, as well as an extended section serving as a manual for new or experienced users.
Agri-'culture' and biodiversity : rethinking payments for ecosystem services in light of relational values
Creators: name: Chapman, Mollie Anne
Publisher: name: University of British Columbia
Year: 2017

description: Agricultural land management has major implications for biodiversity and ecosystem services, including the many cultural and social values that agricultural landscapes provide. A key challenge is balancing trade-offs between these diverse and sometimes conflicting goals. One popular but controversial tool to address this challenge is Payments for Ecosystem Services (PES) programs, which offer agricultural producers monetary compensation for stewardship actions. In this dissertation, I consider the role of environmental values in policy-making and program development, both for PES or alternative policy options to address the ecological impacts of agriculture. The first study examines the consequences of applying a metric (as a simple scientific tool) towards the challenge of food system sustainability in Vancouver, Canada. Via a case study examining four different policy options (including a PES program), I conclude that the Ecological Footprint, when applied as a sustainability metric, led the city towards a ‘metric trap’ that excluded policy options and prioritized particular values. The second study examines an incentive program in Costa Rica that pays farmers to protect forested land. I show that while program management focused on the instrumental values of nature and used an economic framing for the program, most participants focused on values about their relationships to the land (relational values) and saw the program as a type of help or support. The final two studies examine an incentive program for riparian buffers on agricultural land in the Puget Sound region of Washington State (USA). In the third study, I use interviews with land managers to show how key program rules conflict with farmer and rural land manager values. The fourth study draws on expert interviews and document analysis to show the ways that supposedly value-free scientific guidelines, in reality, express a suite of values regarding culture, landscape and place. This dissertation as a whole shows the ways that environmental policies and programs articulate values about what matters, and why, via supposedly value-free rules, regulations, metrics, and guidelines. I conclude by offering suggestions for how agri-environmental incentive programs could be made more effective and popular by incorporating values-thinking.
Pots, Pans, and Pussyhats: The Impacts and Ethics of Feminist Protest Tools
Creators: name: Balasubramanian, Aira
Publisher: name: The University of Texas at Austin
Year: 2022
Subjects: Signature Course Information Literacy Award
Chilean Protests
Allende
Cacerolazo
Women’s March
Pinochet
Pussyhat Protest
Craft Activism
La Vigilia
Josefina Guilisasti

description: This project won first place in the 2023 Signature Course Information Literacy Award. The award recognizes exemplary student work that achieves the learning outcomes of the Signature Course information literacy requirement, that students will be able to create and execute a research strategy, critically evaluate information, and navigate the scholarly conversation. Aira Balasubramanin self-nominated her paper “Pots, Pans, and Pussyhats: The Impacts and Ethics of Feminist Protest Tools” from Arturo De Lozanne’s UGS 303 course Originality in the Arts and Sciences. Her TA, Maureen MacLean said of her paper "Aira contrasts and compares the use of pots and pans in Chilean cacerolazo protests to the "pussyhats" worn by participants of the 2017 Women's March. She ultimately makes a compelling and highly original argument that these methods of protest, while uniting protestors, do not represent the inherent heterogeneity of feminism and can actually exacerbate disparities within and outside the feminist movement. To support this argument, she skillfully utilizes scholarly research found in UT's library catalog spanning the disciplines of feminist studies, sociology, political science, and economic history. ...She produced a beautifully written and rigorously researched paper that far exceeded the work of most Freshmen...the most impressive paper I have seen in all three years I was TA."
description: Feminist protest is a strong catalyzing force for change, politically and socially. However, various social groups under the overarching feminist movement view its’ goals differently, through intersectional lenses of race, class, disability, sexuality, and gender. These factors contribute to relative privilege and marginalization of subgroups within feminist ideology, and determine who has power in designing and demonstrating the goals and symbolic tools of a protest. In some cases, this acts against elevating inclusive policy that elevates feminists’ societal voice and power. This leads us to explore the effect of social and economic privilege in designing effective feminist protest tools within the historical context of Chilean cacerolazo and arpelleria protests, and the modern lens of the “Pussyhat Protest” that swept through the 2017 Women’s March on Washington.