cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Preservation of quantum coherence after exciton-exciton interaction in quantum wells
Creators: name: Garro, N.
name: Kennedy, S.
name: Phillips, R.
name: Aichmayr, G.
name: Rössler, Ulrich
name: Vina, L.
Publisher: name: Universität Regensburg
Year: 2003
Subjects: subject: 530 Physik

description: The dynamics of exciton-exciton interaction in quantum wells has been investigated by monitoring the time-resolved resonant secondary emission that follows excitation with linearly and circularly polarized light. Preservation of quantum beating in the cross-polarized emission demonstrates that spin relaxation can take place, for some scattering channels, without total quantum coherence loss. Interexciton electron exchange is the scattering mechanism that explains the persistence of the beating and, since it is sensitive to the fine structure of excitons, the shift by pi in the phase of the beating observed in the experiment.
Romaerne på fælleden
Creators: name: Frello, Birgitta
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2017

description: Birgitta Frello's article The Roma Squatters on Amager Common deals with two narratives used to understand the situation of Roma people. On the one hand they cannot live up to the deep ingrained understanding that tells us that it is natural for all people to live and die in the country they were born in, the national narrative. On the other they cannot fit into liberalism's (and we could add postmodernism's) story about the positive possibilities inherent in the freedom to move through national borders, enjoying cultural hybridity, multiple identities, etc. Those are reserved for transnationalism from the top, but the Roma are placed among those who practice transnationalism from below: poor immigrants, refugees and others. Birgitta Frello uses the expulsion of some Roma people from Denmark in 2010 as a case study to shed light on the two narratives, their limitations and consequences.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
Anisotropic scattering and quantum magnetoresistivities of a periodiclally modulated 2D electron gas
Creators: name: Manolescu, Andrei
name: Gerhardts, Rolf R.
name: Suhrke, Michael
name: Rössler, Ulrich
Publisher: name: Universität Regensburg
Year: 2001
Subjects: subject: 530 Physik

description: We calculate the longitudinal conductivities of a two-dimensional noninteracting electron gas in a uniform magnetic field and a lateral electric or magnetic periodic modulation in one spatial direction, in the quantum regime. We consider the effects of the electron-impurity scattering anisotropy through the vertex corrections on the Kubo formula, which are calculated with the Bethe-Salpeter equation, in the self-consistent Born approximation. We find that due to the scattering anisotropy the band conductivity increases, and the scattering conductivities decrease and become anisotropic. Our results are in qualitative agreement with recent experiments.
Baheb el Cima
Creators: name: Galal, Lise Paulsen
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2017

description: In Baheb el Cima - The fight of representation in an Egyptian context, Lise Paulsen Galal analyses the global and the local tales which are activated within and around the movie Baheb el Cima in relation to its release in Egypt. Galal illustrates how the global and the local tales apparently converge in the movie, but do not converge outside the movie. The focus in the article is on the tale of freedom, and how this tale is encountered by tales of the nation, the minority and religion.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
nested PLS
Creators: name: Arai, Toshiyasu
Publisher: name: arXiv
Year: 2010
Subjects: subject: Logic (math.LO)
subject: FOS: Mathematics
subject: 03F30

description: In this note we will introduce a class of search problems, called nested Polynomial Local Search (nPLS) problems, and show that definable NP search problems, i.e., $Σ^b_1$-definable functions in $T^2_2$ are characterized in terms of the nested PLS.
Det globale prisuddelingsshow
Creators: name: Haastrup, Helle Kannik
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2017

description: In The global awards - cross-mediality, mainstream movie cult and celebrity matrix, Helle Kannik Haastrup argues that awards have to be considered media events with several functions at the same time. The article mainly treats The Academy Awards, and secondly MTV Movie Awards (2010). According to Haastrup, both awards stage-manage the "red carpet" and the "speech of thanks", and work as a platform for image management of the stars and mediated fashion.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
Cooling and exhumation in the footwall of the Dangardzong fault, Thakkhola graben, west central Nepal
Creators: name: Brubacher, Alex
Publisher: name: University of British Columbia
Year: 2018

description: Late-stage E-W orogen-parallel extension is well documented in the Tibetan plateau, however, the nature and timing of extension related features remains unclear. In order to investigate the temporal development of the graben that accommodate this extension, ⁴⁰Ar/³⁹Ar and U-Th/He thermochronology were used to characterize the evolution of the Thakkhola graben in west-central Nepal, a major N-S striking, E-W extensional structure that cuts across the High Himalaya. The Mugu and Mustang granites occur in the footwall of the Dangardzong fault, which defines the western boundary of the graben. Monazite U-Th/Pb geochronology is used to constrain the minimum crystallization age of these granites to ~22-20 Ma. ⁴⁰Ar/³⁹Ar geochronology of micas date the cooling of the granites through calculated Ar migration closure temperatures (580-344 °C) to ~17 Ma. Zircon and apatite U-Th/He dating yield ages of ~15-9 Ma and ~12-4 Ma, respectively, corresponding to cooling of the granites through respective He migration closure temperatures of ~220-140 °C and ~116-44 °C. Microstructures in rocks collected in this region show that E-W extensional structures were contemporaneous with cooling through muscovite closure to Ar migration at ~17 Ma, providing a minimum age of initiation of extension. Detailed low-temperature cooling paths, based on U-Th/He data extracted from the undeformed intrusive bodies, record inflections in cooling rates at ~13-8 Ma and at ~5 Ma. These two inflections mark deceleration of cooling in the footwall, which is interpreted to reflect a reduction in the spreading rate of the graben. The slowdowns are coeval with increased graben development across the Tibetan plateau and as such are interpreted to reflect strain being partitioned into these newly generated structures. This study adds to a growing body of evidence for a major kinematic shift in the Himalaya occurring around ~13 Ma potentially linked with the flow of material eastward out of the Tibetan plateau.
Accurate Masses for Navarro-Frenk-White Dark Matter Haloes
Creators: name: Evans, N. W.
name: An, J.
name: Deason, A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We consider the problem of estimating the virial mass of a dark halo from the positions and velocities of a tracer population. Although a number of general tools are available, more progress can be made if we are able to specify the functional form of the halo potential (although not its normalization). Here, we consider the particular case of the cosmologically motivated Navarro-Frenk-White (NFW) halo and develop two simple estimators. We demonstrate their effectiveness against numerical simulations and use them to provide new mass estimates of Carina, Fornax, Sculptor, and Sextans dSphs.
description: Ap J (Letters), submitted
The OPTX Project IV: How Reliable is [OIII] as a Measure of AGN Activity?
Creators: name: Trouille, L.
name: Barger, A. J.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We compare optical and hard X-ray identifications of AGNs using a uniformly selected (above a flux limit of f_2-8 keV = 3.5e-15 erg/cm2/s) and highly optically spectroscopically complete ( > 80% for f_2-8 keV > 1e-14 erg/cm2/s and > 60% below) 2-8 keV sample observed in three Chandra fields (CLANS, CLASXS, and the CDF-N). We find that empirical emission-line ratio diagnostic diagrams misidentify 20-50% of the X-ray selected AGNs that can be put on these diagrams as star formers, depending on which division is used. We confirm that there is a large (2 orders in magnitude) dispersion in the log ratio of the [OIII]5007A to hard X-ray luminosities for the non-broad line AGNs, even after applying reddening corrections to the [OIII] luminosities. We find that the dispersion is similar for the broad-line AGNs, where there is not expected to be much X-ray absorption from an obscuring torus around the AGN nor much obscuration from the galaxy along the line-of-sight if the AGN is aligned with the galaxy. We postulate that the X-ray selected AGNs that are misidentified by the diagnostic diagrams have low [OIII] luminosities due to the complexity of the structure of the narrow-line region, which causes many ionizing photons from the AGN not to be absorbed. This would mean that the [OIII] luminosity can only be used to predict the X-ray luminosity to within a factor of ~3 (one sigma). Despite selection effects, we show that the shapes and normalizations of the [OIII] and transformed hard X-ray luminosity functions show reasonable agreement, suggesting that the [OIII] samples are not finding substantially more AGNs at low redshifts than hard X-ray samples.
description: Accepted for publication in the Astrophysical Journal. 11 pages, 10 figures
Groundstate energies of quantum dots in high magnetic fields: A new approach
Creators: name: Kainz, Josef
name: Mikhailov, S.
name: Wensauer, Andreas
name: Rössler, Ulrich
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: Quantum dot; Ground state; High magnetic field; Wigner cluster
subject: 530 Physik

description: We present a method for calculating ground state properties of quantum dots in high magnetic fields which takes into account the equilibrium positions of electrons in a Wigner cluster to minimize the interaction energy and is optimized for the high field limit. Assuming perfect spin alignment the many-body trial function is a single Slater determinant of overlapping oscillator functions from the lowest Landau level centered at and near the classical equilibrium positions. We obtain an analytic expression for the ground state energy and present numerical results for up to N=40.
Myths in advertising
Creators: name: Rubio-Hernández, Maria Del Mar
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2011

description: The starting point of Myths in advertising: current interpretations of ancient tales by María del Mar Rubio-Hernández is that despite the influence of science and technology in today's world, there are still myths that play a critical role in our social imaginary and many of which have different modern manifestations. According to Rubio-Hernández, mass media today could be highlighted as the most efficient vehicle that transmits myths in our culture, since mass media do not only extend those narratives, but also amplify them. Her article specifically focuses on the presence of myths seen in advertisements, and she argues that advertising utilizes elements which are in the collective imaginary, and consequently are already settled in the audience's mind, guaranteeing its recognition and identification.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
Laterrally coupled few-electron quantum dots
Creators: name: Wensauer, Andreas
name: Steffens, Oliver
name: Suhrke, Michael
name: Rössler, Ulrich
Publisher: name: Universität Regensburg
Year: 2000
Subjects: subject: 530 Physik

description: We present ground-state calculations for laterally coupled quantum dots containing two, four, and eight electrons. As our emphasis is on spin effects our results are obtained by applying spin-density functional theory (SDFT). By varying the distance between the centers of the coupled quantum dots, the transition from the weak- to strong-coupling situation is realized. For the two-electron system we also apply the Heitler-London approximation and analytical concepts to check the reliability of SDFT calculations in this case. In addition we discuss the features of the Coulomb staircase of laterally coupled quantum dots in the weak- and strong-coupling regimes in comparison to that of a circular parabolic quantum dot.
Poet-Intellectual and Public Sociologist
Creators: name: Jacobsen, Michael Hviid
name: Tester, Keith
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2011

description: Finally, this issue contains an interview, Poet-Intellectual and Public Sociologist, with Zygmunt Bauman by the Danish sociologist Michael Hviidand the British Keith Tester. Bauman has enriched our understanding of modernity, postmodernity and globalization. In this interview, asked about his audience, the Polish-born sociologist takes us through the different conceptions, especially those the Marxist tradition has developed about the place and role of intellectuals, their mission and importance to society. Bauman focuses specially on Adorno and uses him to emphasize that although we have definitely left behind the idea that intellectuals are historical agents of social transformation, we must not disregard the idea that intellectuals have something to say and that they can be important because we are confronted with suffering, threats and fear. The intellectual can have the privilege of being a detached observer.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
Optical Response and Spin Relaxation in Semiconductor Systems under Excitation with Arbitrary Polarization
Creators: name: Rössler, Ulrich
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: 530 Physik

description: The equations of motion for the density matrix are derived in a multiband model to describe the response of semiconductors (bulk or quantum well structures) under optical excitation with arbitrary polarization. The multiband model used, comprising the twofold conduction band and the fourfold topmost valence band (or heavy- and light-hole states), incorporates spin-splitting of the single-particle states. The interaction terms include besides the direct Coulomb coupling between carriers also the electron-hole exchange interaction, which together with the spin-splitting terms is responsible for spin relaxation. Applying the Hartree-Fock truncation scheme leads to a set of coherent semiconductor Bloch equations for the multiband case. This concept provides the theoretical frame for describing phenomena connected with optical response under excitation with arbitrary light polarization and spin relaxation: polarized optical response, polarization dynamics of VCSELs, spin relaxation, and the circular photovoltaic effect.
Far-infrared response of InAs-GaSb type II quantum dots
Creators: name: Broido, D.
name: Kempa, K.
name: Rössler, Ulrich
Publisher: name: Universität Regensburg
Year: 2000
Subjects: subject: Magneto optics; Quantum dots
subject: 530 Physik

description: We have investigated theoretically the ground state and electromagnetic response of InAs–GaSb type-II quantum dots in the presence of a vertical magnetic field. The ground state is calculated within the Hartree approximation using a 2-band k·p effective mass Hamiltonian to represent the coupling between the two spin-split sets of dot levels derived from the lowest InAs electron subband and the highest GaSb heavy hole subband. The FIR response is calculated within the RPA. We show that the interlayer Coulomb interaction between the electrons and the holes combined with the k·p mixing breaks the generalized Kohn's theorem leading to a complex FIR spectrum.
A New Class of MDS Erasure Codes Based on Graphs
Creators: name: Puttarak, Nattakan
name: Kaewprapha, Phisan
name: Ng, Boon Chong
name: Jing
name: Li
Publisher: name: arXiv
Year: 2011
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: Maximum distance separable (MDS) array codes are XOR-based optimal erasure codes that are particularly suitable for use in disk arrays. This paper develops an innovative method to build MDS array codes from an elegant class of nested graphs, termed \textit{complete-graph-of-rings (CGR)}. We discuss a systematic and concrete way to transfer these graphs to array codes, unveil an interesting relation between the proposed map and the renowned perfect 1-factorization, and show that the proposed CGR codes subsume B-codes as their "contracted" codes. These new codes, termed \textit{CGR codes}, and their dual codes are simple to describe, and require minimal encoding and decoding complexity.
description: in Proceeding of IEEE Global Communications Conference (GLOBECOM)
Spanish educational policy in the Philippine Islands
Creators: name: Whitwell, Charles Garland, 1903-
Publisher: name: The University of Texas at Austin
Year: 1940
Subjects: subject: Education
subject: Philippines
subject: History
subject: Education--Philippines--History

description: The educational policy pursued in all Spanish colonies remained almost exclusively in the hands of the Catholic church and the religious orders until 1863. Prior to that time no effort was made by the Spanish government to establish a system of public schools. The religious made no attempt to unite their schools into a system or to follow any set pattern. The type of school maintained depended upon the individual representatives of the church, on the order, and upon local conditions. When education has been carried on under such conditions, it is naturally very difficult to arrive at definite conclusions as to what was taught--how it was taught--and with what results. For a knowledge of what the civil authorities required to be taught in the Philippine schools, there is available in the Library of Congress a compilation by Daniel Grifol y Aliaga of all the Spanish laws pertaining to primary education. The most important of these laws are available to the student in the extensive work entitled The Philippine Islands, translated and edited by Emma Helen Blair and James A. Robertson. The best available sources of information as to early conditions in the Philippines, what was actually taught in the early schools, and the progress made in imparting western culture to the Filipinos, are the accounts of the religious and the official correspondence of the civil authorities
Special lagrangian fibrations on flag variety $F^3$
Creators: name: Tyurin, Nikolay A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Symplectic Geometry (math.SG)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: One constructs lagrangian fibrations on the flag variety $F^3$ and proves that the fibrations are special.
description: 19 pages
Quantum dots in high magnetic fields: Calculation of ground state properties
Creators: name: Kainz, Josef
name: Mikhailov, S.
name: Wensauer, Andreas
name: Rössler, Ulrich
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: 530 Physik

description: We present a variational method for calculating ground-state properties of quantum dots in high magnetic fields. Assuming a perfect spin alignment, we construct a many-body trial wave function in the form of a single Slater determinant of overlapping oscillator functions from the lowest Landau level centered around some points Ri inside the dot. The points Ri either coincide with the classical equilibrium positions or are considered as variational parameters to minimize the total energy of the system. Using these trial wave functions, we analytically calculate the ground-state properties. We present ground-state energies for up to N = 40 electrons, compare them with available exact results for up to N = 10, and give a transparent interpretation of the results.
Evidence and evaluation of the Bychkov-Rashba effect in SiGe/Si/SiGe quantum wells
Creators: name: Wilamowski, Zbyslaw
name: Jantsch, Wolfgang
name: Malissa, Hans
name: Rössler, Ulrich
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: 530 Physik

description: From spin resonance of two-dimensional (2D) conduction electrons in a modulation doped SiGe/Si/SiGe quantum well structure we find a 2D anisotropy of both the line broadening (dephasing time) and the g factor. Both can be explained consistently employing the Bychkov-Rashba (BR) term H_BR = alpha(k×sigma)·ez, which turns out here to be the dominant coupling between electron orbital motion and spin. We obtain a BR parameter of alpha= 0.55×10–12 eV cm—three orders of magnitude smaller than in quantum well structures based on III-V semiconductors, consistent with the much smaller spin-orbit coupling in Si.
On the formation of single and binary helium-rich sdO stars
Creators: name: Justham, Stephen
name: Podsiadlowski, Philipp
name: Han, Zhanwen
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We propose a formation channel for the previously unexplained helium-rich subdwarf O (He-rich sdO) stars in which post-subdwarf B (sdB) stars (i.e. hybrid COHe white dwarfs) reignite helium burning in a shell after gaining matter from their helium white-dwarf (WD) companions. Such short-period binaries containing post-sdB WDs and helium WDs are predicted by one of the major binary formation channels for sdB stars. In the majority of cases, mass transfer is expected to lead to a dynamically unstable merger event, leaving a single-star remnant. Calculations of the evolution of these stars show that their properties are consistent with the observed He-rich sdO stars. The luminosity of these stars is about an order of magnitude higher than that of canonical sdB stars. We also suggest that binary systems such as PG 1544+488 (Ahmad et al. 2004) and HE 0301-3039 (Lisker et al. 2004), which each contain two hot subdwarfs, could be the outcome of a double-core common-envelope phase. Since this favours intermediate-mass progenitors, this may also explain why the subdwarfs in these systems are He-rich.
description: Accepted by MNRAS
Removal of spin-degenerancy in p-SiGe quantum wells demonstrated by spin-photocurrents
Creators: name: Ganichev, Sergey
name: Rössler, Ulrich
name: Prettl, Wilhelm
name: Ivchenko, E.
name: Belkov, Vassilij
name: Neumann, Richard
name: Brunner, K.
name: Abstreiter, Gerhard
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: 530 Physik

description: Spin photocurrents requiring a system lacking inversion symmetry, become possible in SiGe based quantum well (QW) structures due to their built-in asymmetry. We report on circular and linear photogalvanic effects induced by infrared radiation in (001)- and (113)-oriented p-Si/Si1–xGex QW structures and analyze the observations in view of the possible symmetry of these structures. The circular photogalvanic effect arises due to optical spin orientation of free carriers in QW's with spin-split subbands. It results in a directed motion of free carriers in the plane of the QW. We discuss possible microscopic mechanisms that could remove the spin degeneracy of the electronic subband states.
Paisanos: The Irish and the Liberation of Latin America
Creators: name: Fanning, Tim
Publisher: name: University of Notre Dame
Year: 2023

description: \u000aIn the early nineteenth century, thousands of volunteers left Ireland behind to join the fight for South American independence. Lured by the promise of adventure, fortune, and the opportunity to take a stand against colonialism, they braved the treacherous Atlantic crossing to join the ranks of the Liberator, Sim\u00f3n Bol\u00edvar, and became instrumental in helping oust the Spanish from Colombia, Panama, Venezuela, Ecuador, Peru, and Bolivia. Today, the names of streets, towns, schools, and football teams on the continent bear witness to their influence.\u000a\u000aBut it was not just during wars of independence that the Irish helped transform Spanish America. Irish soldiers, engineers, and politicians, who had fled Ireland to escape religious and political persecution in their homeland, were responsible for changing the face of the Spanish colonies in the Americas during the eighteenth century. They included a chief minister of Spain, Richard Wall; a chief inspector of the Spanish Army, Alexander O'Reilly; and the viceroy of Peru, Ambrose O'Higgins.\u000a \u000aWhether telling the stories of armed revolutionaries like Bernardo O'Higgins and James Rooke or retracing the steps of trailblazing women like Eliza Lynch and Camila O'Gorman, _Paisanos_ revisits a forgotten chapter of Irish history and, in so doing, reanimates the hopes, ambitions, ideals, and romanticism that helped fashion the New World and sowed the seeds of Ireland's revolutions to follow.\u000a
Anisotropic spin splitting and spin relaxation in asymmetric zinc-blende semiconductor quantum structures
Creators: name: Kainz, Josef
name: Rössler, Ulrich
name: Winkler, R.
Publisher: name: Universität Regensburg
Year: 2003
Subjects: subject: 530 Physik

description: Spin relaxation due to the D'yakonov-Perel' mechanism is intimately related with the spin splitting of the electronic states. We determine the spin relaxation rates from anisotropic spin splittings of electron subbands in n-(001) zinc blende semiconductor quantum structures calculated self-consistently in the multiband envelope function approach. The giant anisotropy of spin relaxation rates found for different spin components in the (001) plane can be ascribed to the interplay between the bulk and quantum well inversion asymmetry. One of the in-plane relaxation rates may exhibit a striking nonmonotonous dependence on the carrier density.
Observation of exchange Coulomb interactions in the quantum Hall state at nu=3
Creators: name: Van'kov, A. B.
name: Rhone, T. D.
name: Pinczuk, A.
name: Kukushkin, I. V.
name: Pfeiffer, L. N.
name: West, K. W.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Coulomb exchange interactions of electrons in the nu=3 quantum Hall state are determined from two inter-Landau level spin-flip excitations measured by resonant inelastic light scattering. The two coupled collective excitations are linked to inter-Landau level spin-flip transitions arising from the N=0 and N=1 Landau levels. The strong repulsion between the two spin-flip modes in the long-wave limit is clearly manifested in spectra displaying Coulomb exchange contributions that are comparable to the exchange energy for the quantum Hall state at nu=1. Theoretical calculations within the Hartree-Fock approximation are in a good agreement with measured energies of spin-flip collective excitations.
description: 5 pages, 3 figures, to appear in PRB Rapid Communications
A Spectral Method for Solving the Cauchy Problem
Creators: name: Chelyshkov, Vladimir S.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65L05, 65L06, 65L07

description: A new approach for integration of the initial value problem for ordinary differential equations is suggested. The algorithm is based on approximation of the solution by a system of functions that contains orthogonal exponential polynomials.
description: 5 pages, 1 figure
Temperature dependence of D'yakonov Perel' spin relaxation in zinc blende semiconductor quantum structures
Creators: name: Kainz, Josef
name: Rössler, Ulrich
name: Winkler, R.
Publisher: name: Universität Regensburg
Year: 2004
Subjects: subject: 530 Physik

description: The Dyakonov-Perel mechanism, intimately related to the spin splitting of the electronic states, usually dominates the spin relaxation in zinc-blende semiconductor quantum structures. Previously it has been formulated for the two limiting cases of low and high temperatures. Here we extend the theory to give an accurate description of the intermediate regime which is often relevant for room temperature experiments. Employing the self-consistent multiband envelope function approach, we determine the spin splitting of electron subbands in n-(001) zinc-blende semiconductor quantum structures. Using these results we calculate spin relaxation rates as a function of temperature and obtain excellent agreement with experimental data.
Wellfoundedness proofs by means of non-monotonic inductive definitions II: first order operators
Creators: name: Arai, Toshiyasu
Publisher: name: arXiv
Year: 2010
Subjects: subject: Logic (math.LO)
subject: FOS: Mathematics
subject: 03F35

description: In this paper, we give two proofs of the wellfoundedness of recursive notation systems for $Π_N$-reflecting ordinals. One is based on $Π_{N-1}^0$-inductive definitions, and the other is based on distinguished classes.
Pretransplant calcium levels have no predictive value for delayed graft function, long-term graft function, cardiovascular events, or graft and patient survival in renal transplantation
Creators: name: Krüger, Bernd
name: Schnitzbauer, Andreas A.
name: Böger, Carsten A.
name: Hoffmann, Ute
name: Banas, Bernhard
name: Farkas, Stefan
name: Schlitt, Hans J.
name: Obed, Aiman
name: Krämer, Bernhard K.
Publisher: name: Universität Regensburg
Year: 2006
Subjects: subject: 610 Medizin

description: BACKGROUND: Disorders of calcium homeostasis are one of the most common problems in patients with end-stage renal disease (ESRD). Elevated calcium levels increase the incidence of cardiovascular mortality in ESRD patients, and appear to be a risk factor for the occurrence of delayed graft function (DGF) after kidney transplantation. Therefore, we investigated the impact of pretransplant serum calcium levels on outcomes after kidney transplantation: DGF, acute rejection, graft function, and survival, as well as the incidence of cardiovascular events. METHODS: We studied 285 patients (96.9% of all transplanted patients) who underwent their first transplantation between 1995 and 2004. Demographic data were extracted from hospital records or were documented during follow-up; serum samples were collected at the time of transplantation. RESULTS: In our cohort the incidence of DGF was 16.5% and 35.4% of acute rejection episodes (ARE). However, pretransplant calcium levels were not related to DGF or ARE in our patient cohort. Furthermore, there was no correlation between pretransplant serum calcium level with the incidence of cardiovascular events or mortality, as well as graft function or survival. CONCLUSION: In our study population pretransplant calcium levels showed no effect on DGF, ARE rate, the occurrence of cardiovascular events or death, renal graft function, or survival. Therefore, pretransplant calcium level is not a helpful marker for risk stratification at the time of transplantation.
Hybridism in the understanding of media “stories”
Creators: name: Marinescu, Valentina
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2011

description: Valentina Marinescu's Hybridism in the understanding of media "stories" - An analysis of the Romanian popularity of K-drama treats a very recent phenomenon in Romania: the nation-wide exposure to "Hallyru" popular culture products. The article aims at explaining the reasons of the popularity of this type of products with the Romanian viewers, and to give an answer to how Korean historical drama series viewing influence Romanians' perceptions in general and especially their perceptions of Asia.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
On the Exploratory Road to Unraveling Factor Loading Non-invariance: A New Multigroup Rotation Approach
Creators: name: Roover, Kim De
name: Vermunt, Jeroen K.
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Physiology
subject: FOS: Biological sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics
subject: Developmental Biology
subject: 111714 Mental Health
subject: FOS: Health sciences

description: Multigroup exploratory factor analysis (EFA) has gained popularity to address measurement invariance for two reasons. Firstly, repeatedly respecifying confirmatory factor analysis (CFA) models strongly capitalizes on chance and using EFA as a precursor works better. Secondly, the fixed zero loadings of CFA are often too restrictive. In multigroup EFA, factor loading invariance is rejected if the fit decreases significantly when fixing the loadings to be equal across groups. To locate the precise factor loading non-invariances by means of hypothesis testing, the factors’ rotational freedom needs to be resolved per group. In the literature, a solution exists for identifying optimal rotations for one group or invariant loadings across groups. Building on this, we present multigroup factor rotation (MGFR) for identifying loading non-invariances. Specifically, MGFR rotates group-specific loadings both to simple structure and between-group agreement, while disentangling loading differences from differences in the structural model (i.e., factor (co)variances).
Mindful listening : Indigenous adult basic education learners speak about returning to school
Creators: name: Emmonds, Francine
Publisher: name: University of British Columbia
Year: 2018

description: Returning to school to complete secondary studies is a pivotal event in the life of an Indigenous adult learner, yet there is a gap in the academic literature about student voices describing their experiences. This qualitative case study from the unceded traditional territories of the Musqueam, Squamish and Tsleil-Waututh First Nations focused on students at the Native Education College urban Indigenous adult learning centre. The study sought to make space for student storywork that expressed important elements of adult basic education (ABE) learner experiences. A conceptual framework based on oral traditional teachings of maskikimiskanow (the medicine journey), and of mino pimatisiwin (a good life), as well as the Seven Teachings of respect, honesty, courage, love, humility, wisdom and truth, informed an Indigenous methodology that incorporated culturally relevant research methods and an overall approach that sought to demonstrate respect and relationality. Thirteen students were interviewed and shared some of their stories of returning to school. School instructors, administrators, Elders – in residence, and one student supporter were also interviewed about ABE and lifelong learning. Cree Elders from Saskatchewan and from my home area of Ochekwi Sipi, Manitoba were consulted, as well as two additional instructor / administrators. Thematic analyses revealed factors of the greatest importance to the students’ experiences of returning to school were motivation and readiness to return to school, participation in the intake assessment, and the finding of community within the school. The greatest impact was the finding of supportive, culturally connected community within the school. This occurred as a result of peer, Elder, and staff support, and the everyday “place” of the school that offered culturally relevant supports with its Longhouse structure and tangible connections to a physical place on the land where people gathered to be and to learn. This research contributes valuable information for other prospective adult learners, Tribal education authorities, ABE instructors, administrators, and policy and programming personnel. It adds to the academic literature for Indigenous ABE subject matter and Indigenous research methodology. In bringing a strong student perspective from these adult learners, this research values, acknowledges, and empowers their voices and story contributions.
Biopics as Postmodern Mythmaking
Creators: name: Cucca, Valentina
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2011

description: Biopics as Postmodern Mythmaking by Valentina Cucca takes as its starting point the fact that the biographical genre has experienced a renewed prominence. The main goal of her article is to identify links and connections between many contemporary socio-cultural issues and the ways in which biopics are able to thematize and rework them. She also aims at explaining which have been and are the more or less intrinsic changes and trends of this genre, which have led to rank current productions under a label (biopic). Finally, Cucca aims at revealing to which extent biopics' symbolical universes are able to thematize, reflect and rework social, political and cultural identity uncertainties that have invested postmodern subjectivities.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
Spin-Photocurrent in p-SiGe quantum wells under terahertz laser irradiation
Creators: name: Belkov, Vassilij
name: Ganichev, Sergey
name: Schneider, Petra
name: Schowalter, D.
name: Rössler, Ulrich
name: Prettl, Wilhelm
name: Ivchenko, E.
name: Neumann, Richard
name: Brunner, K.
name: Abstreiter, Gerhard
Publisher: name: Universität Regensburg
Year: 2003
Subjects: subject: SiGe-QWs; photogalvanic effect; Rashba term.
subject: 530 Physik

description: A detailed study of the circular photogalvanic effect (CPGE) in SiGe structures is presented. It is shown that the CPGE becomes possible because of the built-in asymmetry of quantum wells (QWs) in compositionally stepped samples and in asymmetrically doped structures. The photocurrent arises due to optical spin orientation of free carriers in QWs with spin splitting in k-space. It is shown that the effect can be applied to probe the macroscopic in-plane symmetry of low dimensional structures and allowing to conclude on Rashba or Dresselhaus terms in the Hamiltonian.
“Which of you shall we say doth love us most”
Creators: name: Pannen, Imke
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2011

description: "Which of you shall we say doth love us most" - King Lear and the necessity of salt by Imke Pannen is initiated by the idea that the motifs of parents' love for their children and children's love for their parents are common themes in various narratives of all mankind. According to Pannen, the idea of a parent demanding a declaration of his or her child's love is a less recurrent topic in literature, but it does figure in myths and fairy tales. In the article, the focus is on this theme in Shakespeare's tragedy King Lear and The Salt Prince.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
Theory of the spin singlett filling factor nu=2 quantum Hall droplet
Creators: name: Wensauer, Andreas
name: Korkusinski, Marek
name: Hawrylak, Pawel
Publisher: name: Universität Regensburg
Year: 2003
Subjects: subject: 530 Physik

description: A theory of electronic properties of a spin-singlet quantum Hall droplet at filling factor nu= 2 in a parabolic quantum dot is developed. The excitation spectrum and the stability of the droplet due to the transfer of electrons into the second Landau level at low magnetic fields and due to spin flip at the edge at higher magnetic fields are determined using Hartree-Fock, exact diagonalization, and spin-density functional methods. We show that above a critical number of electrons Nc the unpolarized nu= 2 quantum Hall droplet ceases to be a ground state in favor of spin-polarized phases. We determine the characteristic pattern in the addition and current-amplitude Coulomb blockade spectra associated with the stable nu= 2 droplet. We show that the spin transition of the droplet at a critical number of electrons is accompanied by the reversal of the current-amplitude modulation at the nu= 2 line, as observed in recent experiments.
Functional analysis of KNOTTED-like homeobox and OVATE family proteins involved in secondary cell wall development in Arabidopsis
Creators: name: Wang, Shumin
Publisher: name: University of British Columbia
Year: 2019

description: The formation of plant secondary cell walls requires a complex network of transcriptional regulation, culminating in a coordinated suite of biosynthetic genes depositing walls, in a spatial and temporal fashion. The transcription factor KNOTTED ARABIDOPSIS THALIANA7 (KNAT7) is a Class II KNOTTED1-like homeobox (KNOX2) gene, that acts as a negative regulator of secondary cell wall biosynthesis in interfascicular fibers. Previously, members of Ovate Family Proteins (OFP1 and OFP4), were shown to interact with KNAT7 to negatively regulate wall formation. However, the function of other closely related KNOX2 and OFP genes in secondary wall formation remains unclear. Herein, I showed that knat3knat7 double mutants possess an enhanced irregular xylem (irx) phenotype relative to single mutants, and decreased interfascicular fiber cell wall thickness. Additionally, unlike the increased lignin content characteristic of knat7 mutants, knat3knat7 had no change in lignin content, while the monomeric lignin composition was substantially reduced relative to the wild-type plants. In contrast, KNAT3 overexpression resulted in thicker interfascicular fiber secondary walls, suggesting a positive regulation of KNAT3 in wall development. A thorough examination of OFP mutants showed that none of the single mutants revealed any wall defects, including ofp4, which was previously shown to interact with KNAT7. However, they do display leaf phenotypes. In contrast, plants overexpressing OFP isoforms consistently exhibited cell swelling, disordered microtubules, and dark-grown de-etiolated phenotypes, resembling phenotypes common to brassinosteroid deficient mutants. Using yeast two-hybrid and bimolecular fluorescence complementation assays, I identified two genes that interacted with OFP4, NAP1;1 and NAP1;2, members of the Nucleosome Assembly Protein 1 (NAP1) family. Higher-order, loss-of-function NAP1 and OFP mutants also exhibit altered cotyledon shape and a reduced cotyledon width:length ratio. The kidney-shaped cotyledon phenotype apparent in OFP4 overexpressing plants was suppressed in the nap1;1 nap1;2 nap1;3 triple mutant background. Together, my research suggests that in addition to KNAT7, KNAT3 also contributes to cell wall deposition, and that a complex network of positive and negative regulation governed by KNOX2 proteins regulates secondary wall formation. Moreover, the complex of OFP4 and NAP1 plays a significant role in the cotyledon development.
Two-Level Dynamic Structural Equation Models with Small Samples
Creators: name: McNeish, Daniel
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Genetics
subject: FOS: Biological sciences
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Immunology
subject: FOS: Clinical medicine
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics
subject: 110309 Infectious Diseases
subject: FOS: Health sciences

description: Advances in data collection have made intensive longitudinal data easier to collect, unlocking potential for methodological innovations to model such data. Dynamic structural equation modeling (DSEM) is one such methodology but recent studies have suggested that its small N performance is poor. This is problematic because small N data are omnipresent in empirical applications due to logistical and financial concerns associated with gathering many measurements on many people. In this paper, we discuss how previous studies considering small samples have focused on Bayesian methods with diffuse priors. The small sample literature has shown that diffuse priors may cause problems because they become unintentionally informative. Instead, we outline how researchers can create weakly informative admissible-range-restricted priors, even in the absence of previous studies. A simulation study shows that metrics like relative bias and non-null detection rates with these admissible-range-restricted priors improve small N properties of DSEM compared to diffuse priors.
Rædsler fra Ribe og omegn
Creators: name: Clasen, Mathias
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2011

description: In Horrors from Ribe and its environs: the horror tale as a global tale, Mathias Clasen takes as a starting point the fact that the human beings from all documented cultures spend a lot of time in fictive worlds , considering that their biological goal is to pass along their genes. According to Clasen, this suggests that art has deep roots in the human biological design. Through a reading of Teddy Vorks' horror novel The Dike, Clasen supports Joseph Caroll's hypothesis; that literature makes us better at surviving and reproducing, because fictive tales can make us better at understanding and navigating in both our inner as our outer landscapes.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
Testing the Limits
Creators: name: Buxton, Camille Alexander
Publisher: name: Akademisk kvarter | Academic Quarter
Year: 2011

description: Testing the Limits: Forbidden Love in Two Anglophone Caribbean Texts by Camille Alexander Buxton is initiated by the discussion whether forbidden love, a form of romantic love that is a recurrent theme in literature, is constructed or natural. In the article the theme is addressed as a characteristic of natural, human emotions rather than a social construct with a specific code of conduct, indicative of Western culture. Forbidden love is a theme in some Caribbean texts, and in the article, Buxton examines texts from two Trinidadian authors, Shani Mootoo's (2005) He Drown She in the Sea and Elizabeth Nunez's (2006) Prospero's Daughter.
description: Akademisk kvarter | Academic Quarter, Global Tales | Globale fortællinger, Vol. 2
HAT-P-16b: A 4 Mj Planet Transiting A Bright Star On An Eccentric Orbit
Creators: name: Buchhave, L. A.
name: Bakos, G. A.
name: Hartman, J. D.
name: Torres, G.
name: Kovacs, G.
name: Latham, D. W.
name: Noyes, R. W.
name: Esquerdo, G. A.
name: Everett, M.
name: Howard, A. W.
name: Marcy, G. W.
name: Fischer, D. A.
name: Johnson, J. A.
name: Andersen, J.
name: Furesz, G.
name: Perumpilly, G.
name: Sasselov, D. D.
name: Stefanik, R. P.
name: Beky, B.
name: Lazar, J.
name: Papp, I.
name: Sari, P.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We report the discovery of HAT-P-16b, a transiting extrasolar planet orbiting the V = 10.8 mag F8 dwarf GSC 2792-01700, with a period P = 2.775960 +- 0.000003 d, transit epoch Tc = 2455027.59293 +- 0.00031 (BJD), and transit duration 0.1276 +- 0.0013 d. The host star has a mass of 1.22 +- 0.04 Msun, radius of 1.24 +- 0.05 Rsun, effective temperature 6158 +-80 K, and metallicity [Fe/H] = +0.17 +- 0.08. The planetary companion has a mass of 4.193 +- 0.094 MJ, and radius of 1.289 +- 0.066 RJ yielding a mean density of 2.42 +- 0.35 g/cm3. Comparing these observed characteristics with recent theoretical models, we find that HAT-P-16b is consistent with a 1 Gyr H/He-dominated gas giant planet. HAT-P-16b resides in a sparsely populated region of the mass{radius diagram and has a non-zero eccentricity of e = 0.036 with a significance of 10 sigma.
description: Submitted to ApJ