cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Structure of A Heterogeneous Two-Phase Rotating Detonation Wave with Ethanol-Hydrogen-Air Mixture
Creators: name: Yao, Songbai
name: Tang, Xinmeng
name: Zhang, Wenwu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: In this short Letter, the structure of a rotating detonation wave (RDW) fueled by biofuel is revealed and expounded. The simulation is carried out under an Eulerian-Lagrangian framework in which the main characteristics of the two-phase RDW are analyzed in detail. Results suggest a self-sustained rotating detonation fueled by liquid ethanol and air can be achieved with hydrogen addition for combustion enhancement, and a laminated dual-front structure of the RDW due to the effect of droplet evaporation is captured and clarified.
Model Hamiltonian for Topological Insulators
Creators: name: Liu, Chao-Xing
name: Qi, Xiao-Liang
name: Zhang, HaiJun
name: Dai, Xi
name: Fang, Zhong
name: Zhang, Shou-Cheng
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In this paper we give the full microscopic derivation of the model Hamiltonian for the three dimensional topological insulators in the $Bi_2Se_3$ family of materials ($Bi_2Se_3$, $Bi_2Te_3$ and $Sb_2Te_3$). We first give a physical picture to understand the electronic structure by analyzing atomic orbitals and applying symmetry principles. Subsequently, we give the full microscopic derivation of the model Hamiltonian introduced by Zhang {\it et al} [\onlinecite{zhang2009}] based both on symmetry principles and the ${\bf k}\cdot{\bf p}$ perturbation theory. Two different types of $k^3$ terms, which break the in-plane full rotation symmetry down to three fold rotation symmetry, are taken into account. Effective Hamiltonian is derived for the topological surface states. Both the bulk and the surface models are investigated in the presence of an external magnetic field, and the associated Landau level structure is presented. For more quantitative fitting to the first principle calculations, we also present a new model Hamiltonian including eight energy bands.
description: 18 pages, 9 figures, 5 tables
Tree-based solvers for adaptive mesh refinement code FLASH -- IV: An X-ray radiation scheme to couple discrete and diffuse X-ray emission sources to the thermochemistry of the interstellar medium
Creators: name: Gaches, Brandt A. L.
name: Walch, Stefanie
name: Wünsch, Richard
name: Mackey, Jonathan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: X-ray radiation, in particular radiation between 0.1 keV and 10 keV, is evident from both point-like sources, such as compact objects and T-Tauri young stellar objects, and extended emission from hot, cooling gas, such as in supernova remnants. The X-ray radiation is absorbed by nearby gas, providing a source of both heating and ionization. While protoplanetary chemistry models now often include X-ray emission from the central young stellar object, simulations of star-forming regions have yet to include X-ray emission coupled to the chemo-dynamical evolution of the gas. We present an extension of the {\sc TreeRay} reverse raytrace algorithm implemented in the {\sc Flash} magneto-hydrodynamic code which enables the inclusion of X-ray radiation from 0.1 keV $< E_γ <$ 100 keV, dubbed {\rm XrayTheSpot}. {\sc XrayTheSpot} allows for the use of an arbitrary number of bins, minimum and maximum energies, and both temperature-independent and temperature-dependent user-defined cross sections, along with the ability to include both point and extended diffuse emission and is coupled to the thermochemical evolution. We demonstrate the method with several multi-bin benchmarks testing the radiation transfer solution and coupling to the thermochemistry. Finally, we show two example star formation science cases for this module: X-ray emission from protostellar accretion irradiating an accretion disk and simulations of molecular clouds with active chemistry, radiation pressure, protostellar radiation feedback from infrared to X-ray radiation.
description: Accepted to MNRAS
FAIR-Checker, a web tool to support the findability and reusability of digital life science resources
Creators: name: Rosnet, Thomas
name: Lefort, Vincent
name: Devignes, Marie-Dominique
name: Gaignard, Alban
Publisher: name: Zenodo
Year: 2021
Subjects: Open Sciences
FAIR Metrics
Knowledge Graphs
Linked Data
FAIR Data
RDF, SPARQL, SHACL

description: The explosion of web-accessible digital resources makes the discovery of meaningful datasets, softwares, methods, training, challenging for scientists. Providing machine-readable metadata is the cornerstone to scale up the development and adoption of Open Sciences. It is urgent to better share and reuse biological digital resources. FAIR principle are currently being adopted by many scientific communities. However, assessing how much a resource is FAIR is nowadays challenging. Answering human-oriented questionnaires is time-consuming and computational evaluations (FAIRMetrics, RDA Maturity Indicators) often require technical expertise. In this work, we aim at empowering scientists and developers in FAIRifing their resources from the very early stages.
Phase and amplitude of Aharonov-Bohm oscillations in nonlinear three-terminal transport through a double quantum dot
Creators: name: Kubo, Toshihiro
name: Ichigo, Yuki
name: Tokura, Yasuhiro
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study three-terminal linear and nonlinear transport through an Aharonov-Bohm interferometer containing a double quantum dot using the nonequilibrium Green's function method. Under the condition that one of the three terminals is a voltage probe, we show that the linear conductance is symmetric with respect to the magnetic field (phase symmetry). However, in the nonlinear transport regime, the phase symmetry is broken. Unlike two-terminal transport, the phase symmetry is broken even in noninteracting electron systems. Based on the lowest-order nonlinear conductance coefficient with respect to the source-drain bias voltage, we discuss the direction in which the phase shifts with the magnetic field. When the higher harmonic components of the Aharonov-Bohm oscillations are negligible, the phaseshift is a monotonically increasing function with respect to the source-drain bias voltage. To observe the Aharonov-Bohm oscillations with higher visibility, we need strong coupling between the quantum dots and the voltage probe. However, this leads to dephasing since the voltage probe acts as a Büttiker dephasing probe. The interplay between such antithetic concepts provides a peak in the visibility of the Aharonov-Bohm oscillations when the coupling between the quantum dots and the voltage probe changes.
description: 17 pages, 9 figures, accepted for publication in Physical Review B
Greek-Turkish Relations and the Cyprus dispute: impact on Turkey-EU scenarios
Creators: name: Dokos, Thanos
name: Tocci, Nathalie
name: Palm, Anja
name: Kasapoğlu, Can
Publisher: name: Zenodo
Year: 2018
Subjects: European Union; Turkey; EU-Turkey relations; Greek-Turkish Relations; Cyprus dispute; Turkey-EU scenarios; Greek Cypriot; Cyprus; Greece; Politics; Dilpomacy; Conflictual Cooperation

description: FEUTURE Online Paper No. 27

Greek-Turkish relations have come under significant strain in the last couple of years and are likely to remain difficult in the long-run there seems to be little appetite in both sides of the Aegean for a substantive discussion and subsequent negotiation for the full normalization of Greek-Turkish relations as both sides are either faced with pressing domestic priorities or with important external challenges and have no intention of spending precious political and diplomatic capital for the resolution of bilateral problems, at least in the immediate future. A Cyprus settlement has been extremely difficult to achieve over the past (almost) half a century and there is rather limited optimism that the situation will change in the near future. The sad truth is that three of the four parties to the conflict are relatively content with the status quo, or at least insufficiently unhappy with it to make the painful and risky compromises an agreement would warrant. Particularly for a large part of the Greek Cypriot community, the status quo appears to be preferable to a federal peace agreement which is being perceived as problematic, especially regarding security provisions. Therefore, the most probable scenario is ‘business as usual/muddling through’ akin to the “conflictual cooperation” scenario identified in other workstreams.
description: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 692976. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein.
Controlling two-dimensional Coulomb crystals of more than 100 ions in a monolithic radio-frequency trap
Creators: name: Kiesenhofer, Dominik
name: Hainzer, Helene
name: Zhdanov, Artem
name: Holz, Philip C.
name: Bock, Matthias
name: Ollikainen, Tuomas
name: Roos, Christian F.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Linear strings of trapped atomic ions held in radio-frequency (rf) traps constitute one of the leading platforms for quantum simulation experiments, allowing for the investigation of interacting quantum matter. However, linear ion strings have drawbacks, such as the difficulty to scale beyond $\sim 50$ particles as well as the inability to naturally implement spin models with more than one spatial dimension. Here, we present experiments with planar Coulomb crystals of about 100 $^{40}$Ca$^+$ ions in a novel monolithic rf trap, laying the groundwork for quantum simulations of two-dimensional spin models with single-particle control. We characterize the trapping potential by analysis of crystal images and compare the observed crystal configurations with numerical simulations. We further demonstrate stable confinement of large crystals, free of structural configuration changes, and find that rf heating of the crystal is not an obstacle for future quantum simulation experiments. Finally, we prepare the out-of-plane motional modes of planar crystals consisting of up to 105 ions close to their ground state by electromagnetically-induced transparency cooling, an important prerequisite for implementing long-range entangling interactions.
Circular photogalvanic effect induced by monopolar spin orientation in p-GaAs/AlGaAs MQW
Creators: name: Ganichev, Sergey
name: Ivchenko, Eougenious
name: Ketterl, Hermann
name: Prettl, Wilhelm
name: Vorobjev, L.
Publisher: name: Universität Regensburg
Year: 2000
Subjects: subject: 530 Physik

description: The circular photogalvanic effect (CPGE) has been observed in (100)-oriented p-GaAs/AlGaAs quantum wells at normal incidence of far-infrared radiation. It is shown that monopolar optical spin orientation of free carriers causes an electric current which reverses its direction upon changing from left to right circularly polarized radiation. CPGE at normal incidence and the occurrence of the linear photogalvanic effect indicate a reduced point symmetry of studied multilayered heterostructures. As proposed, CPGE can be utilized to investigate separately spin polarization of electrons and holes and the symmetry of quantum wells.
Radiative corrections to neutron beta decay and (anti)neutrino-nucleon scattering from low-energy effective field theory
Creators: name: Tomalak, Oleksandr
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We study radiative corrections to neutron beta decay and low-energy (anti)neutrino-nucleon scattering within a top-down effective field theory approach. As it was recently shown, a few electromagnetic and electroweak low-energy coupling constants in heavy-baryon chiral perturbation theory are yet to be determined. Performing matching to the four-fermion effective field theory, we relate these low-energy constants to correlation functions of vector and axial-vector currents. Such relations allow us to explicitly clarify scheme dependence for radiative corrections to neutron decay and low-energy charged-current (anti)neutrino scattering, provide a robust prediction of leading in the electromagnetic coupling constant contributions, and achieve a clear separation between short-distance and long-distance contributions.
description: 19 pages, 3 figures
Mass Functions in Fractal Clouds: The Role of Cloud Structure in the Stellar Initial Mass Function
Creators: name: Shadmehri, Mohsen
name: Elmegreen, Bruce G.
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: The possibility that the stellar initial mass function (IMF) arises mostly from cloud structure is investigated with fractal Brownian motion (fBm) clouds that have power-law power spectra. An fBm cloud with a realistic projected power spectrum slope of $β=2.8$ is found to have a mass function for clumps exceeding a threshold density that is a power-law with a slope of $α=2.35$, the same as in the Salpeter IMF. Any hierarchically structured cloud has a clump mass function with about the same slope. This result implies that turbulent interstellar clouds produce dense substructure with the observed pre-stellar core mass function built in from the start. Details of the clump formation processes are not critical. The conversion of clumps into stars involves a second step. A one-to-one correspondence between clump mass and star mass is not necessary to convert the clump mass spectrum into an IMF with the same power-law slope. As long as clumps have an internal stellar IMF from sub-fragmentation, protostellar accretion, coalescence and other processes, and the characteristic mass for this internal IMF scales with the clump mass, then the IMF slope above the minimum characteristic mass will equal the clump mass slope. A detailed review of IMF models illustrates the prominence of cloud structure as a major component in a wide class of theories. Tests are proposed to determine the relative importance of cloud structure and competitive accretion in the IMF.
description: 19 pages, 12 figures, accepted for publication in MNRAS
Small loop spaces and covering theory of non-homotopically Hausdorff spaces
Creators: name: Pakdaman, Ali
name: Torabi, Hamid
name: Mashayekhy, Behrooz
Publisher: name: arXiv
Year: 2010
Subjects: subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 57M10, 57M05, 55Q05, 57M12

description: In this paper we devote to spaces that are not homotopically hausdorff and study their covering spaces. We introduce the notion of small covering and prove that every small covering of $X$ is the universal covering in categorical sense. Also, we introduce the notion of semi-locally small loop space which is the necessary and sufficient condition for existence of universal cover for non-homotopically hausdorff spaces, equivalently existence of small covering spaces. Also, we prove that for semi-locally small loop spaces, $X$ is a small loop space if and only if every cover of $X$ is trivial if and only if $π_1^{top}(X)$ is an indiscrete topological group.
description: 7 pages
Spin sensitive bleaching and monopolar spin orientation in quantum wells
Creators: name: Ganichev, Sergey
name: Danilov, Sergey
name: Belkov, Vassilij
name: Ivchenko, Eougenious
name: Bichler, Max
name: Wegscheider, Werner
name: Weiss, Dieter
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: 530 Physik

description: Spin-sensitive bleaching of the absorption of far-infrared radiation has been observed in p-type GaAs AlGaAs quantum well structures. The absorption of circularly polarized radiation saturates at lower intensities than that of linearly polarized light due to monopolar spin orientation in the first heavy-hole subband. Spin relaxation times of holes in p-type material in the range of tens of ps were derived from the intensity dependence of the absorption.
The Role of the Middle East in the EU-Turkey Security Relationship: Key Drivers and Future Scenarios
Creators: name: Ergun, Doruk
name: Dessi, Andrea
name: Lindgaard, Jakob
name: Ala'Aldeen, Dlawer
name: Palani, Kamaran
Publisher: name: Zenodo
Year: 2018
Subjects: European Union; Turkey; EU-Turkey Relations; Middle East; Security Policy; Key Drivers; Future Scenarios; Conflictual Multipolarity; Transnational Terrorism; Radicalization; Kurdish Issue; Regional Instability; Power Vacuum; Non-State Actors

description: FEUTURE Online Paper No. 20

This paper analyses the effects of developments in the Middle East since 1999 on the security relationship between the European Union (EU) and Turkey. The chronological outlook allows us to identify three main drivers in the relationship. The first is ‘conflictual multipolarity,’ i.e. the conventional and non-conventional competition between different state actors in the Middle East. A cause and effect of this is regional instability and power vacuums, which create environments conducive for armed non-state actors to flourish. Second, transnational terrorism and radicalization which presents major threats to both parties and serves as potential drivers for cooperation if Ankara and EU states can agree on the risks and definitions posed by armed non-state actors. Third and perhaps most salient, is the Kurdish issue, which has seen a transformation from a primarily domestic issue for Turkey into an issue of regional and international magnitude, pitting the EU and Turkey in opposing camps.
description: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 692976. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein.
Nonlinear photogalvanic effect induced by monopolar spin orientation of holes in MQWs
Creators: name: Ganichev, Sergey
name: Danilov, Sergey
name: Ivchenko, Eougenious
name: Ketterl, H.
name: Vorobjev, L.
name: Bichler, Max
name: Wegscheider, Werner
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 2001
Subjects: subject: Photogalvanic effect; Monopolar spin orientation
subject: 530 Physik

description: We report on the first observation of the circular photogalvanic effect (CPGE) induced by optical monopolar spin orientation of holes in p-doped quantum-well structures. It is shown that monopolar optical spin orientation of free carriers causes an electric current which reverses its direction upon changing from left to right circularly polarized radiation. The effect has been observed in (0 0 1)- and (3 1 1)A-oriented p-GaAs/AlGaAs quantum wells at normal incidence of far-infrared radiation. The photocurrent is proportional to the light intensity at low power levels and gradually saturates with increasing intensity. The CPGE can be utilized to investigate separately spin polarization of electrons and holes and to determine spin-relaxation times.
The Three Faces of the Second Law: I. Master Equation Formulation
Creators: name: Esposito, Massimiliano
name: Broeck, Christian Van den
Publisher: name: arXiv
Year: 2010
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We propose a new formulation of stochastic thermodynamics for systems subjected to nonequilibrium constraints (i.e. broken detailed balance at steady state) and furthermore driven by external time-dependent forces. A splitting of the second law occurs in this description leading to three second law like relations. The general results are illustrated on specific solvable models. The present paper uses a master equation based approach.
description: 10 pages, 3 figures
Optical spin orientation under inter- and intra-subband transitions in QWs
Creators: name: Tarasenko, Sergey
name: Ivchenko, Eougenious
name: Belkov, Vassilij
name: Ganichev, Sergey
name: Schowalter, Dieter
name: Schneider, Petra
name: Sollinger, M.
name: Prettl, Wilhelm
name: Ustinov, V.
name: Zhukov, A.
name: Vorobjev, L.
Publisher: name: Universität Regensburg
Year: 2003
Subjects: subject: spin orientation; infrared absorption; intraband transitions; spin-related current
subject: 530 Physik

description: It is shown that absorption of circularly polarized infrared radiation achieved by inter-subband and intra-subband (Drude-like) transitions results in a monopolar spin orientation of free carriers. The monopolar spin polarization in zinc-blende-based quantum wells (QWs) is demonstrated by the observation of the spin-galvanic and circular photogalvanic effects. It is shown that monopolar spin orientation in n-type QWs becomes possible if an admixture of valence band states to the conduction band wave function and the spin–orbit splitting of the valence band are taken into account.
title: The labour supply and retirement of older workers: an empirical analysis
Creators: name: Allan, Stephen
Publisher: name: University of Kent
Year: 2022

description: This thesis examines the labour supply of older workers, their movement into retirement, and any movement out of retirement and back into work. In particular the labour force participation, labour supply and wage elasticity and other income elasticity of work hours are estimated for older workers and compared to younger workers. The thesis goes on to look at the movement into retirement for older workers as a whole by examining cohorts by gender, wave and age. The thesis also presents a descriptive and quantitative • examination of the changes in income and happiness that occur as an individual retires. Finally the thesis examines the reasons why an individual may return to work from v . retirement. The results of the findings suggest: that younger workers are significantly more responsive to wage and household income changes than older workers
Sequential pattern mining in educational data: The application context, potential, strengths, and limitations
Creators: name: Zhang, Yingbin
name: Paquette, Luc
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Increasingly, researchers have suggested the benefits of temporal analysis to improve our understanding of the learning process. Sequential pattern mining (SPM), as a pattern recognition technique, has the potential to reveal the temporal aspects of learning and can be a valuable tool in educational data science. However, its potential is not well understood and exploited. This chapter addresses this gap by reviewing work that utilizes sequential pattern mining in educational contexts. We identify that SPM is suitable for mining learning behaviors, analyzing and enriching educational theories, evaluating the efficacy of instructional interventions, generating features for prediction models, and building educational recommender systems. SPM can contribute to these purposes by discovering similarities and differences in learners' activities and revealing the temporal change in learning behaviors. As a sequential analysis method, SPM can reveal unique insights about learning processes and be powerful for self-regulated learning research. It is more flexible in capturing the relative arrangement of learning events than the other sequential analysis methods. Future research may improve its utility in educational data science by developing tools for counting pattern occurrences as well as identifying and removing unreliable patterns. Future work needs to establish a systematic guideline for data preprocessing, parameter setting, and interpreting sequential patterns.
description: This is a preprint of the following chapter: Yingbin Zhang & Luc Paquette (2023). Sequential pattern mining in educational data: The application context, potential, strengths, and limitations. In Alejandro Pe\~na-Ayala (Eds), Educational Data Science: Essentials, Approaches, and Tendencies. Springer. https://link.springer.com/book/9789819900251
Giant negative magnetoresistance in semiconductors doped by multiply charged deep impurities
Creators: name: Ganichev, Sergey
name: Ketterl, Hermann
name: Prettl, Wilhelm
name: Merkulov, I.
name: Perel, V.
name: Yassievich, Irina
name: Malyshev, A.
Publisher: name: Universität Regensburg
Year: 2001
Subjects: subject: 530 Physik

description: A giant negative magnetoresistance has been observed in bulk germanium doped with multiply charged deep impurities. Applying a magnetic field the resistance may decrease exponentially at any orientation of the field. A drop of the resistance as much as about 10 000% has been measured at 6 T. The effect is attributed to the spin splitting of impurity ground state with a very large g factor in the order of several tens depending on impurity.
Multilingual lexicon design tool and database management system for MT
Creators: name: Barisevičius, G.
name: Tamulynas, B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Computation and Language (cs.CL)
subject: FOS: Computer and information sciences

description: The paper presents the design and development of English-Lithuanian-English dictionarylexicon tool and lexicon database management system for MT. The system is oriented to support two main requirements: to be open to the user and to describe much more attributes of speech parts as a regular dictionary that are required for the MT. Programming language Java and database management system MySql is used to implement the designing tool and lexicon database respectively. This solution allows easily deploying this system in the Internet. The system is able to run on various OS such as: Windows, Linux, Mac and other OS where Java Virtual Machine is supported. Since the modern lexicon database managing system is used, it is not a problem accessing the same database for several users.
Mitigating the downstream effects of excess soil phosphorus through cultivar selection and increased foliar resorption
Creators: name: Da Ros, Letitia
Publisher: name: University of British Columbia
Year: 2018

description: Elemental phosphorus has been categorized as a non-renewable resource that is crucial to global food security. This is largely due to the transport of phosphorus being dependent on aqueous transfer and therefore an inherent inability to return to upstream ecosystems. It is only through mining and transport of rock phosphate that agricultural land remains productive. Simultaneously, due to agricultural over-fertilization, phosphorus has been characterized as a pollutant in aquatic environments. Diffuse source run-off from high phosphorus soils continues to contribute to downstream eutrophication decades after nutrient management practices have been put into place. A potential solution involves planting high biomass-producing tree species along riparian areas. Trees belonging to the Salicaceae are ideal candidates as they have a wide geographical distribution in Canada and broad-scale applications, ranging from fibre production to biofuel feedstock to uses in phytoremediation. The objective of this thesis was to identify a commercially available tree genotype, be it poplar or willow, well suited for widespread planting in agricultural areas to limit nutrient enrichment of riparian ecosystems. Phenotypic differences in phosphorus storage and allocation were analyzed using ICP-AES and HPLC. Poplar varieties Tristis and Northwest demonstrated the highest capacity for luxury uptake with an estimated 3.7 – 3.9 mg P g-¹ when 2.2 mM soluble phosphate (100N:70P) was applied, with no measurable metabolic consequences. However, the majority of phosphorus was stored in leaves as phosphate and subsequently returned to the environment as autumnal senescence progressed. This led to the exploration of factors limiting phosphate translocation and resorption. Expression of an exogenous phosphate H⁺/H₂PO₄- symporter in poplar led to a small, but significant increase in phosphate resorption and a pronounced increase in sulfate resorption, leading to further questions surrounding anion efflux from the vacuole and the role of the tonoplast in limiting nutrient translocation. If resorption proficiency could be increased under the high nutrient loads found in productive lands, poplar genotypes with luxury consumption could be bred for improved resorption and used to reduce phosphorus entry into riparian ecosystems. Extrapolation of this information to crop species could lead to reduced fertilizer application and improved nutrient management of perennial production systems.
Lepton flavour universality test at the CERN NA62 experiment
Creators: name: Goudzovski, Evgueni
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: A precision test of lepton universality by measurement of the ratio RK of K-->e nu to K-->mu nu decay rates was performed using a sample of 59963 K-->e nu candidates with 8.8% background contamination collected by the CERN NA62 experiment. The result RK = (2.486 +- 0.013)*10^{-5} is in agreement with the Standard Model expectation.
description: A talk given at the BEACH 2010 conference (Perugia, June 2010). 6 pages, 4 figures
Photogalvanic effects in quantum wells
Creators: name: Ganichev, Sergey
name: Ivchenko, Eougenious
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: Photogalvanic effect; Spin orientation; Quantum wells
subject: 530 Physik

description: Circular and linear photogalvanic effects induced by far-infrared radiation have been investigated in both n-type and p-type quantum wells (QWs) of various point symmetry groups. The circular photogalvanic effect arises due to optical spin orientation of free carriers in QWs which results in a directed motion of free carriers in the plane of a QW perpendicular to the direction of light propagation. Due to selection rules the direction of the current is determined by the helicity of the light and can be reversed by switching the helicity from right to left.
Accumulation of scale-free localized states induced by local non-Hermiticity
Creators: name: Guo, Cui-Xian
name: Wang, Xueliang
name: Hu, Haiping
name: Chen, Shu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: The bulk states of Hermitian systems are believed insensitive to local Hermitian impurities or perturbations except for a few impurity-induced bound states. Thus, it is important to ask whether \textit{local} non-Hermiticity can cause drastic changes to the original Hermitian systems. Here we address this issue affirmatively and present exact solutions for the double chain model with local non-Hermitian terms possessing parity-time ($\mathcal{PT}$) symmetry. Induced by the non-Hermiticity, the system undergoes a sequence of $\mathcal{PT}$-symmetry breakings, after which the eigenenergies appear in complex conjugate pairs. The associated extended bulk states then become scale-free localized and unidirectionally accumulated around the impurity. There exist mobility edges separating the residual extended states until a full scale-free localization of all eigenstates. Further increasing the non-Hermitity counter-intuitively brings the system to a $\mathcal{PT}$-restoration regime with fully real spectra except for a pair of complex bound states. We demonstrate that the local non-Hermiticity generated scale-free localization is a general phenomenon and can even survive the quasiperiodic disorder. Our results indicate that the bulk properties of the original Hermitian system can be globally reshaped by local non-Hermiticity.
description: 14 pages, 11 figures, published version in Phys. Rev. B as Editors' Suggestion
Crowd-Feedback in Information Systems Development: A State-of-the-Art Review
Creators: name: Haug, Saskia
name: Mädche, Alexander
Publisher: name: Association for Information Systems (AIS)
Year: 2021

description: Crowd-feedback is receiving increasing attention in research and practice as a contemporary approach for involving users in information systems development. Thereby, feedback on various aspects of an information system is collected from a non-expert crowd using designated crowd-feedback systems that are able to collect comprehensive and reliable feedback at scale. However, the current body of knowledge on crowd-feedback is scattered and lacks a structured form in which research on crowd-feedback can be classified. To address this gap, this article provides a comprehensive overview of the state-of-the-art of existing crowd-feedback research by: (1) conducting a systematic literature review, (2) developing a morphological box to conceptualize crowd-feedback, and (3) performing a cluster analysis for identifying research streams on crowd-feedback. Analyzing 40 articles, our key contribution resides in the synopsis of the existing crowd-feedback literature. Based on our review, we suggest four research avenues to guide researchers in investigating crowd-feedback in the future.
Tunneling ionization of deep centers in terahertz electric fields
Creators: name: Ganichev, Sergey
name: Yassievich, Irina
name: Prettl, Wilhelm
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: 530 Physik

description: Experimental and theoretical work on the ionization of deep impurity centres in the alternating terahertz field of high-intensity far-infrared laser radiation, with photon energies tens of times lower than the impurity ionization energy, is reviewed. It is shown that impurity ionization is due to phonon-assisted tunnelling which proceeds at high electric field strengths into direct tunnelling without involving phonons. In the quasi-static regime of low frequencies the tunnelling probability is independent of frequency. Carrier emission is accomplished by defect tunnelling in configuration space and electron tunnelling through the potential well formed by the attractive force of the impurity and the externally applied electric field. The dependence of the ionization probability on the electric field strength permits one to determine defect tunnelling times, the structure of the adiabatic potentials of the defect, and the Huang–Rhys parameters of electron–phonon interaction. Raising the frequency leads to an enhancement of the tunnelling ionization and the tunnelling probability becomes frequency dependent. The transition from the frequency-independent quasi-static limit to frequency-dependent tunnelling is determined by the tunnelling time which is, in the case of phonon-assisted tunnelling, controlled by the temperature. This transition to the high-frequency limit represents the boundary between semiclassical physics, where the radiation field has a classical amplitude, and full quantum mechanics where the radiation field is quantized and impurity ionization is caused by multiphoton processes. In both the quasi-static and the high-frequency limits, the application of an external magnetic field perpendicular to the electric field reduces the ionization probability when the cyclotron frequency becomes larger than the reciprocal tunnelling time and also shifts the boundary between the quasi-static and the frequency-dependent limits to higher frequencies. At low intensities, ionization of charged impurities may also occur through the Poole–Frenkel effect by thermal excitation over the potential well formed by the Coulomb potential and the applied electric field. Poole–Frenkel ionization precedes the range of phonon-assisted tunnelling on the electric field scale and enhances the ionization probability at low electric field strengths. Applying far-infrared lasers as sources of a terahertz electric field, the Poole–Frenkel effect can clearly be observed, allowing one to reach a conclusion regarding the charge of deep impurities.
Locking classical information
Creators: name: Dupuis, Frédéric
name: Florjanczyk, Jan
name: Hayden, Patrick
name: Leung, Debbie
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: It is known that the maximum classical mutual information that can be achieved between measurements on a pair of quantum systems can drastically underestimate the quantum mutual information between those systems. In this article, we quantify this distinction between classical and quantum information by demonstrating that after removing a logarithmic-sized quantum system from one half of a pair of perfectly correlated bitstrings, even the most sensitive pair of measurements might only yield outcomes essentially independent of each other. This effect is a form of information locking but the definition we use is strictly stronger than those used previously. Moreover, we find that this property is generic, in the sense that it occurs when removing a random subsystem. As such, the effect might be relevant to statistical mechanics or black hole physics. Previous work on information locking had always assumed a uniform message. In this article, we assume only a min-entropy bound on the message and also explore the effect of entanglement. We find that classical information is strongly locked almost until it can be completely decoded. As a cryptographic application of these results, we exhibit a quantum key distribution protocol that is "secure" if the eavesdropper's information about the secret key is measured using the accessible information but in which leakage of even a logarithmic number of key bits compromises the secrecy of all the others.
description: 32 pages, 2 figures
Simulation of a viscous fluid spreading by a bidimensional shallow water model
Creators: name: Di Martino, Bernard
name: Giacomoni, Catherine
name: Paoli, Jean-Martin
name: Simonnet, Pierre
Publisher: name: arXiv
Year: 2011
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: In this paper we propose a numerical method to solve the Cauchy problem based on the viscous shallow water equations in an horizontally moving domain. More precisely, we are interested in a flooding and drying model, used to modelize the overflow of a river or the intrusion of a tsunami on ground. We use a non conservative form of the two-dimensional shallow water equations, in eight velocity formulation and we build a numerical approximation, based on the Arbitrary Lagrangian Eulerian formulation, in order to compute the solution in the moving domain.
Bath optimization in the Cellular Dynamical Mean Field Theory
Creators: name: Senechal, David
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: In the Cellular Dynamical Mean Field Theory (CDMFT), a strongly correlated system is represented by a small cluster of correlated sites, coupled to an adjustable bath of uncorrelated sites simulating the cluster's environment; the parameters governing the bath are set by a self-consistency condition involving the local Green function and the lattice electron dispersion. Solving the cluster problem with an exact diagonalization method is only practical for small bath sizes (8 sites). In that case the self-consistency condition cannot be exactly satisfied and is replaced by a minimization procedure. There is some freedom in the definition of the `merit function' to optimize. We use Potthoff's Self-Energy Functional Approach on the one- and two-dimensional Hubbard models to gain insight into the best choice for this merit function. We argue that several merit functions should be used and preference given to the one that leads to the smallest gradient of the Potthoff self-energy functional. We propose a new merit function weighted with the self-energy that seems to fit the Mott transition in two dimensions better than other merit functions.
description: 8 pages, 7 figures.
Oxygen and Neon Abundances of B-Type Stars in Comparison with the Sun
Creators: name: Takeda, Yoichi
name: Kambe, Eiji
name: Sadakane, Kozo
name: Masuda, Seiji
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: To revisit the long-standing problem of possible inconsistency concerning the oxygen composition in the current galactic gas and in the solar atmosphere (i.e., the former being appreciably lower by ~0.3 dex) apparently contradicting the galactic chemical evolution, we carried out oxygen abundance determinations for 64 mid- through late-B stars by using the O I 6156-8 lines while taking into account the non-LTE effect, and compared them with the solar O abundance established in the same manner. The resulting mean oxygen abundance was = 8.71 (+/- 0.06), which means that [O/H] (star-Sun differential abundance) is ~-0.1, the difference being less significant than previously thought. Moreover, since the 3D correction may further reduce the reference solar oxygen abundance (8.81) by ~0.1 dex, we conclude that the photospheric O abundances of these B stars are almost the same as that of the Sun. We also determined the non-LTE abundances of neon for the sample B stars from Ne I 6143/6163 lines to be = 8.02 (+/- 0.09), leading to the Ne-to-O ratio of ~0.2 consistent with the recent studies. This excludes a possibility of considerably high Ne/O ratio once proposed as a solution to the confronted solar model problem.
description: 11 pages, 7 figures, 2 tables, accepted for publication in PASJ, Vol.62, No.5 (2010)
Modes of Regional Cooperation and their Political Economy
Creators: name: Berulava, George
name: Manoli, Panagiota
name: Selçuki, Can
Publisher: name: Zenodo
Year: 2019
Subjects: European Union; Turkey; EU-Turkey Relations; Regional Cooperation; Political Economy; Economic Cooperation; Customs Union; TPP; TTIP; Economy; Regional Player; Global Player; Political Tensions

description: FEUTURE Online Paper No. 29

With the accession talks at a virtual halt, economic cooperation presents itself as one of the few open areas of dialogue between the EU and Turkey. On the one hand, Turkey is trying to reposition itself as a regional and global player weighing its options outside of the EU in terms of economic cooperation. On the other hand, both parties agree to the need to upgrade the current limited Customs Union (CU) agreement. Outside of but highly relevant for the political tensions between the two long term partners, the world trading regime is on the verge of major changes through mega trade agreements such as the TPP and the TTIP. Although currently rising trade wars seem to shadow the multilateral trade regime, big deals are to come whether bilateral or otherwise. More than the EU, Turkey will need to shape its policy to prevent potential losses. This paper evaluates different modes of economic cooperation between the EU and Turkey as well as Turkey’s potential involvement in partnerships outside of the EU.
description: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 692976. This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein.
A microscopic analogue of the BMS group
Creators: name: Weiss, Daniel Alexander
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We consider a microscopic analogue of the BMS analysis of asymptotic symmetries by analysing universal geometric structures on infinitesimal tangent light cones. Thereby, two natural microscopic symmetry groups arise: A non-trivially represented Lorentz group and a BMS-like group. The latter has a rich mathematical structure, since it contains the former as a non-canonical subgroup, next to infinitely many other Lorentz subgroups. None of those Lorentz subgroups appears to be intrinsically preferred, and hence, the microscopic BMS-like group constitutes a natural symmetry group for infinitesimal tangent light cones. We compare our investigation with the classical BMS analysis and show, that the microscopic BMS-like group is a gauge group for the bundle of null vectors. Motivated by the various applications of the original BMS group, our findings could have interesting implications: They identify a geometric structure that could be suitable for a bulk analysis of gravitational waves, they suggest a possible enlargement of the fundamental gauge group of gravity and they motivate the possibility of an interrelation between the UV structure of gauge theories, gravitational memory effects and BMS-like symmetries. Also, our results imply, that BMS-like groups arise not only as macroscopic, asymptotic symmetry groups in cosmology, but describe also a fundamental and seemingly unknown microscopic symmetry of pseudo-Riemannian geometry.
description: 47 pages, wording changed
Temperature dependence of the lower critical field of the noncentrosymmetric superconductor $α$-BiPd
Creators: name: Juraszek, J.
name: Konczykowski, M.
name: Kaczorowski, D.
name: Cichorek, T.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Temperature variation of the lower critical field in the noncentrosymmetric superconductor $α$-BiPd was probed by local magnetization measurements using Hall micromagnetometry, performed down to 0.3 K in a magnetic field applied along the crystallographic $b$ axis. Below a critical temperature $T_c \simeq$ 3.8 K, a conventional $H_{c1}(T)$ dependence was found, typical for a single-band $s$-wave BCS superconductor. The obtained data imply an absence of spin-triplet component in the superconducting wavefunction and marginal multiband effects in this material, which contradicts some literature reports.
description: 14 pages, 5 figures
The solar magnetic field since 1700: I. Characteristics of sunspot group emergence and reconstruction of the butterfly diagram
Creators: name: Jiang, Jie
name: Cameron, Robert H.
name: Schmitt, Dieter
name: Schuessler, Manfred
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We use the historic record of sunspot groups compiled by the Royal Greenwich Observatory together with the sunspot number to derive the statistical properties of sunspot group emergence in dependence of cycle phase and strength. In particular we discuss the latitude, longitude, area and tilt angle of sunspot groups as functions of the cycle strength and of time during the solar cycle. Using these empirical characteristics the time-latitude diagram of sunspot group emergence (butterfly diagram) is reconstructed from 1700 onward on the basis of the Wolf and group sunspot numbers. This reconstruction will be useful in studies of the long-term evolution of the Sun's magnetic field.
description: A&A, accepted