cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
title: Focal adhesion kinase plays a dual role in TRAIL resistance and metastatic outgrowth of malignant melanoma
Creators: name: Del Mistro, Greta
name: Riemann, Shamala
name: Schindler, Sebastian
name: Beissert, Stefan
name: Kontermann, Roland E.
name: Ginolhac, Aurelien
name: Halder, Rashi
name: Presta, Luana
name: Sinkkonen, Lasse
name: Sauter, Thomas
name: Kulms, Dagmar
Publisher: name: Universität Stuttgart
Year: 2022
Subjects: subject: 570

description: Despite remarkable advances in therapeutic interventions, malignant melanoma (MM) remains a life-threating disease. Following high initial response rates to targeted kinase-inhibition metastases quickly acquire resistance and present with enhanced tumor progression and invasion, demanding alternative treatment options. We show 2nd generation hexameric TRAIL-receptor-agonist IZI1551 (IZI) to effectively induce apoptosis in MM cells irrespective of the intrinsic BRAF/NRAS mutation status. Conditioning to the EC50 dose of IZI converted the phenotype of IZI-sensitive parental MM cells into a fast proliferating and invasive, IZI-resistant metastasis. Mechanistically, we identified focal adhesion kinase (FAK) to play a dual role in phenotype-switching. In the cytosol, activated FAK triggers survival pathways in a PI3K- and MAPK-dependent manner. In the nucleus, the FERM domain of FAK prevents activation of wtp53, as being expressed in the majority of MM, and consequently intrinsic apoptosis. Caspase-8-mediated cleavage of FAK as well as FAK knockdown, and pharmacological inhibition, respectively, reverted the metastatic phenotype-switch and restored IZI responsiveness. FAK inhibition also re-sensitized MM cells isolated from patient metastasis that had relapsed from targeted kinase inhibition to cell death, irrespective of the intrinsic BRAF/NRAS mutation status. Hence, FAK-inhibition alone or in combination with 2nd generation TRAIL-receptor agonists may be recommended for treatment of initially resistant and relapsed MM, respectively.
Geologic setting, mineralization, and aspects of zoning at the Berg porphyry copper-molybdenum deposit, Central British Columbia
Creators: name: Panteleyev, Andrejs
Publisher: name: University of British Columbia
Year: 2010

description: Berg copper-molybdenum deposit is in mountainous terrain of the Tahtsa Range in west-central British Columbia. It is a type example of Lowell and Guilbert's (1970) model of porphyry copper deposits. The deposit is in thermally metamorphosed and hydrothermally altered Middle Jurassic volcanic rocks and Tertiary quartz diorite adjacent to a weakly mineralized Eocene stock. The stock is about 2,100 feet in diameter and consists of four major quartz monzonitic phases. Unmineralized volcanic and sedimentary strata of the Cretaceous Skeena Group crop out east of the deposit. Hydrothermal alteration and sulphide minerals are arranged in concentric, annular zones around the composite stock. From the interior outward pervasive alteration zones are potassic, phyllic, and propylitic. Argillic alteration is rare. A biotitic alteration zone that surrounds the stock is largely a thermal aureole but is also partially of hydro-thermal origin. A multistage vein stockwork is superimposed on the pervasively altered rocks. Early veins, many with alteration envelopes, were deposited from saline fluids at temperatures in excess of 400 degrees centigrade. Later veins were deposited from cooler, less saline fluids and commonly have retrograde alteration margins. A gypsum-filled sub-horizontal fracture cleavage cuts all alteration minerals and veins. The molybdenite zone follows closely the intrusive contact where a quartz stockwork is well developed. Chalcopyrite is most abundant in the biotitic alteration zone. Pyrite forms a broad halo that extends outward for at least 2,000 feet from the stock. Minor elements In pyrite are concentrated in disseminated pyrite from well-mineralized copper zones. Leaching and supergene mineralization cause pronounced vertical zoning in the deposit. In the leached capping copper has been removed to a depth of 125 feet but molybdenum remains and is locally concentrated in limonite. In the supergene zone, which overlies the entire deposit and is up to 300 feet thick, copper is enriched by a factor of 1.25 times primary grade. Supergene mineralization is a contemporary ongoing process that was initiated after Pleistocene glaciation.
Multi-Attribute Relation Extraction (MARE) -- Simplifying the Application of Relation Extraction
Creators: name: Klöser, Lars
name: Kohl, Philipp
name: Kraft, Bodo
name: Zündorf, Albert
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: Artificial Intelligence (cs.AI)
subject: Information Retrieval (cs.IR)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Natural language understanding's relation extraction makes innovative and encouraging novel business concepts possible and facilitates new digitilized decision-making processes. Current approaches allow the extraction of relations with a fixed number of entities as attributes. Extracting relations with an arbitrary amount of attributes requires complex systems and costly relation-trigger annotations to assist these systems. We introduce multi-attribute relation extraction (MARE) as an assumption-less problem formulation with two approaches, facilitating an explicit mapping from business use cases to the data annotations. Avoiding elaborated annotation constraints simplifies the application of relation extraction approaches. The evaluation compares our models to current state-of-the-art event extraction and binary relation extraction methods. Our approaches show improvement compared to these on the extraction of general multi-attribute relations.
description: Preprint of short paper for the 2nd International Conference on Deep Learning Theory and Applications (2021)
Diseño de indicadores de desempeño de la actividad científica y editorial de Angola en Acceso Abierto
Creators: name: United Nations Educational, Scientific and Cultural Organization
name: Ministério Do Ensino Superior, Ciência
name: Redalyc-Universidad Autónoma Del Estado De México
name: AmeliCA
name: Universidade Óscar Ribas
Publisher: name: Zenodo
Year: 2022
Subjects: Acceso Abierto
Angola
África
Indicadores de desempeño
Actividad científica de Angola
Actividad editorial de Angola

description: Trabajo derivado del proyecto de colaboración entre Redalyc UAEM, AmeliCA, MESCTI y U. Óscar Ribas financiado por UNESCO para el desarrollo de una estrategia de Acceso Abierto en Angola. Vol. 17 de 38
Transverse kink oscillations of inhomogeneous prominence threads: numerical analysis and H$α$ forward modelling
Creators: name: Martínez-Gómez, David
name: Soler, Roberto
name: Terradas, Jaume
name: Khomenko, Elena
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Prominence threads are very long and thin flux tubes which are partially filled with cold plasma. Observations have shown that transverse oscillations are frequent in these solar structures. The observations are usually interpreted as the fundamental kink mode, while the detection of the first harmonic remains elusive. Here, we aim to study how the density inhomogeneity in the longitudinal and radial directions modify the periods and damping times of kink oscillations, and how this effect would be reflected in observations. We solve the ideal magnetohydrodynamics equations through two different methods: a) performing 3D numerical simulations, and b) solving a 2D generalised eigenvalue problem. We study the dependence of the periods, damping times and amplitudes of transverse kink oscillations on the ratio between the densities at the centre and at the ends of the tube, and on the average density. We apply forward modelling on our 3D simulations to compute synthetic H$α$ profiles. We confirm that the ratio of the period of the fundamental oscillation mode to the period of the first harmonic increases as the ratio of the central density to the footpoint density is increased or as the averaged density of the tube is decreased. We find that the damping times due to resonant absorption decrease as the central to footpoint density ratio increases. Contrary to the case of longitudinally homogeneous tubes, we find that the damping time to period ratio also increases as the density ratio is increased or the average density is reduced. We present snapshots and time-distance diagrams of the emission in the H$α$ line. The results presented here have implications for the field of prominence seismology. While the H$α$ emission can be used to detect the fundamental mode, the first harmonic is barely detectable in H$α$. This may explain the lack of detections of the first harmonic.
description: 17 pages, 16 figures, 4 movies. Accepted for publication in Astronomy & Astrophysics
Patterns of Flavour Violation in a Warped Extra Dimensional Model with Custodial Protection
Creators: name: Gori, Stefania
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present a particular warped extra dimensional model, where the flavour diagonal and flavour non-diagonal Z boson couplings to left-handed down quarks are protected by the custodial symmetry P_LR. After a brief introduction of the model and of its main theoretical motivations, we present a complete study of rare K and B meson decays, including K+ --> pi+ nu anti-nu, K_L --> pi0 nu anti-nu, B_{s,d} --> mu+ mu- and B_{s,d} --> X_{s,d} nu anti-nu. In particular we restrict the parameter space of the model to the subspace which fits all quark masses, CKM mixing parameters and all the measured Delta F=2 observables, keeping the Kaluza-Klein scale in the reach of LHC (~(2-3)TeV). There we show that, in addition to the one loop contribution of the Standard Model (SM), the dominating new physics contribution to the rare decays of K and B_{s,d} mesons is the tree level exchange of the Z boson of the SM governed by right-handed couplings to down-type quarks. In order to reduce the parameter dependence, we study correlations between various branching ratios of B and K mesons and between Delta F=1 and Delta F=2 observables. The patterns that we find allow to distinguish this new physics scenario from the SM and can offer an opportunity to future experiments to confirm or rule out the model.
description: 10 pages, 8 figures, To appear in the proceedings of DISCRETE '08, 11-16 December 2008, Valencia, Spain
Hopping modulation in a one-dimensional Fermi-Hubbard Hamiltonian
Creators: name: Massel, F.
name: Leskinen, M. J.
name: Torma, P.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We consider a strongly repulsive two-component Fermi gas in a one-dimensional (1D) optical lattice described in terms of a Hubbard Hamiltonian. We analyze the response of the system to a periodic modulation of the hopping amplitude in presence of large two body interaction. By (essentially) exact simulations of the time evolution, we find a non-trivial double occupancy frequency dependence. We show how the dependence relates to the spectral features of the system given by the Bethe ansatz. The discrete nature of the spectrum is clearly reflected in the double occupancy after long enough modulation time. We also discuss the implications of the 1D results to experiments in higher dimensional systems.
description: 4 pages, 5 figures; minor changes in the text, updated references;
title: Targeting oncogenic TERT promoter variants by allele-specific epigenome editing
Creators: name: Kouroukli, Alexandra G.
name: Rajaram, Nivethika
name: Bashtrykov, Pavel
name: Kretzmer, Helene
name: Siebert, Reiner
name: Jeltsch, Albert
name: Bens, Susanne
Publisher: name: Universität Stuttgart
Year: 2023
Subjects: subject: 540
subject: 570

description: Background. Activation of dominant oncogenes by small or structural genomic alterations is a common driver mechanism in many cancers. Silencing of such dominantly activated oncogenic alleles, thus, is a promising strategy to treat cancer. Recently, allele-specific epigenome editing (ASEE) has been described as a means to reduce transcription of genes in an allele-specific manner. In cancer, specificity to an oncogenic allele can be reached by either targeting directly a pathogenic single-nucleotide variant or a polymorphic single-nucleotide variant linked to the oncogenic allele. To investigate the potential of ASEE in cancer, we here explored this approach by targeting variants at the TERT promoter region. The TERT promoter region has been described as one of the most frequently mutated non-coding cancer drivers. Results. Sequencing of the TERT promoter in cancer cell lines showed 53% (41/77) to contain at least one heterozygous sequence variant allowing allele distinction. We chose the hepatoblastoma cell line Hep-G2 and the lung cancer cell line A-549 for this proof-of-principle study, as they contained two different kinds of variants, namely the activating mutation C228T in the TERT core promoter and the common SNP rs2853669 in the THOR region, respectively. These variants were targeted in an allele-specific manner using sgRNA-guided dCas9-DNMT3A-3L complexes. In both cell lines, we successfully introduced DNA methylation specifically to the on-target allele of the TERT promoter with limited background methylation on the off-target allele or an off-target locus ( VEGFA ), respectively. We observed a maximum CpG methylation gain of 39% and 76% on the target allele when targeting the activating mutation and the common SNP, respectively. The epigenome editing translated into reduced TERT RNA expression in Hep-G2. Conclusions. We applied an ASEE-mediated approach to silence TERT allele specifically. Our results show that the concept of dominant oncogene inactivation by allele-specific epigenome editing can be successfully translated into cancer models. This new strategy may have important advantages in comparison with existing therapeutic approaches, e.g., targeting telomerase, especially with regard to reducing adverse side effects.
Private sector PrEP delivery policy and regulatory landscaping in Sub-Saharan Africa
Creators: name: Rencken, Cami
name: Azie, Jacinta Ifunanya
name: Yang, Angela
name: Levin, Carol
name: Walson, Judd
name: START Center
Publisher: name: Gates Open Research
Year: 2023

description: The primary objective of this project was to conduct a landscape assessment of regulatory and policy barriers to PrEP (oral and long-acting) delivery through private sector pharmacies and clinics across Sub-Saharan Africa.
Time Variability of Quasars: the Structure Function Variance
Creators: name: MacLeod, C.
name: Ivezic, Z.
name: de Vries, W.
name: Sesar, B.
name: Becker, A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Significant progress in the description of quasar variability has been recently made by employing SDSS and POSS data. Common to most studies is a fundamental assumption that photometric observations at two epochs for a large number of quasars will reveal the same statistical properties as well-sampled light curves for individual objects. We critically test this assumption using light curves for a sample of $\sim$2,600 spectroscopically confirmed quasars observed about 50 times on average over 8 years by the SDSS stripe 82 survey. We find that the dependence of the mean structure function computed for individual quasars on luminosity, rest-frame wavelength and time is qualitatively and quantitatively similar to the behavior of the structure function derived from two-epoch observations of a much larger sample. We also reproduce the result that the variability properties of radio and X-ray selected subsamples are different. However, the scatter of the variability structure function for fixed values of luminosity, rest-frame wavelength and time is similar to the scatter induced by the variance of these quantities in the analyzed sample. Hence, our results suggest that, although the statistical properties of quasar variability inferred using two-epoch data capture some underlying physics, there is significant additional information that can be extracted from well-sampled light curves for individual objects.
description: Presented at the "Classification and Discovery in Large Astronomical Surveys" meeting, Ringberg Castle, 14-17 October, 2008
The Hierarchical Subspace Iteration Method for Laplace--Beltrami Eigenproblems
Creators: name: Nasikun, Ahmad
name: Hildebrandt, Klaus
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: Computational Geometry (cs.CG)
subject: Graphics (cs.GR)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: I.3.5; G.1.3

description: Sparse eigenproblems are important for various applications in computer graphics. The spectrum and eigenfunctions of the Laplace--Beltrami operator, for example, are fundamental for methods in shape analysis and mesh processing. The Subspace Iteration Method is a robust solver for these problems. In practice, however, Lanczos schemes are often faster. In this paper, we introduce the Hierarchical Subspace Iteration Method (HSIM), a novel solver for sparse eigenproblems that operates on a hierarchy of nested vector spaces. The hierarchy is constructed such that on the coarsest space all eigenpairs can be computed with a dense eigensolver. HSIM uses these eigenpairs as initialization and iterates from coarse to fine over the hierarchy. On each level, subspace iterations, initialized with the solution from the previous level, are used to approximate the eigenpairs. This approach substantially reduces the number of iterations needed on the finest grid compared to the non-hierarchical Subspace Iteration Method. Our experiments show that HSIM can solve Laplace--Beltrami eigenproblems on meshes faster than state-of-the-art methods based on Lanczos iterations, preconditioned conjugate gradients and subspace iterations.
description: 14 pages
Compensating the Noise of a Communication Channel via Asymmetric Encoding of Quantum Information
Creators: name: Lucamarini, Marco
name: Di Giuseppe, Giovanni
name: Vitali, David
name: Tombesi, Paolo
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: An asymmetric preparation of the quantum states sent through a noisy channel can enable a new way to monitor and actively compensate the channel noise. The paradigm of such an asymmetric treatment of quantum information is the Bennett 1992 protocol, in which the ratio between conclusive and inconclusive counts is in direct connection with the channel noise. Using this protocol as a guiding example, we show how to correct the phase drift of a communication channel without using reference pulses, interruptions of the quantum transmission or public data exchanges.
description: 5 pages, 3 figures
Painlev{é} singularity structure analysis of three component Gross-Pitaevskii type equations
Creators: name: Kanna, T.
name: Sakkaravarthi, K.
name: Kumar, C. Senthil
name: Lakshmanan, M.
name: Wadati, M.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: In this paper, we have studied the integrability nature of a system of three coupled Gross-Pitaevskii type nonlinear evolution equations arising in the context of spinor Bose-Einstein condensates by applying the Painlevé singularity structure analysis. We show that only for two sets of parametric choices, corresponding to the known integrable cases, the system passes the Painlevé test.
description: 17 pages. Accepted in Journal of Mathematical Physics
Average reduced model to simulate solutions for heat and mass transfer through porous material
Creators: name: Berger, Julien
name: Abdykarim, Madina
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Computer and information sciences

description: The design of numerical tools to model the behavior of building materials is a challenging task. The crucial point is to save computational cost and maintain high accuracy of predictions. There are two main limitations on the time scale choice, which put an obstacle to solve the above issues. First one is the numerical restriction. A number of research is dedicated to overcome this limitation and it is shown that it can be relaxed with innovative numerical schemes. The second one is the physical restriction. It is imposed by properties of a material, phenomena itself and corresponding boundary conditions. This work is focused on the study of a methodology that enables to overcome the physical restriction on the time grid. So-called Average Reduced Model (ARM) is suggested. It is based on smoothing the time-dependent boundary conditions. Besides, the approximate solution is decomposed into average and fluctuating components. The primer is obtained by integrating the equations over time, whereas the latter is an user-defined empirical model. The methodology is investigated for both heat diffusion and coupled heat and mass transfer. It is demonstrated that the signal core of the boundary conditions is preserved and the physical restriction can be relaxed. The model proved to be reliable, accurate and efficient also in comparison with the experimental data of two years. The implementation of the scarce time-step of $1 \, \sf{h}$ is justified. It is shown, that by maintaining the tolerable error it is possible to cut computational effort up to almost four times in comparison with the complete model with the same time grid.
Discovery and characterization of WASP-6b, an inflated sub-Jupiter mass planet transiting a solar-type star
Creators: name: Gillon, M.
name: Anderson, D. R.
name: Triaud, A. H. M. J.
name: Hellier, C.
name: Maxted, P. F. L.
name: Pollaco, D.
name: Queloz, D.
name: Smalley, B.
name: West, R. G.
name: Wilson, D. M.
name: Bentley, S. J.
name: Cameron, A. Collier
name: Enoch, B.
name: Hebb, L.
name: Horne, K.
name: Irwin, J.
name: Joshi, Y. C.
name: Lister, T. A.
name: Mayor, M.
name: Pepe, F.
name: Parley, N.
name: Segransan, D.
name: Udry, S.
name: Wheatley, P. J.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We report the discovery of WASP-6b, an inflated sub-Jupiter mass planet transiting every 3.3610060 +0.0000022-0.0000035 days a mildly metal-poor solar-type star of magnitude V=11.9. A combined analysis of the WASP photometry, high-precision followup transit photometry and radial velocities yield a planetary mass M_p = 0.503 +0.019-0.038 M_jup and radius R_p = 1.224 +0.051-0.052 R_jup, resulting in a density rho_p = 0.27 +-0.05 rho_jup. The mass and radius for the host star are M_s = 0.88 +0.05-0.08 M_sun and R_s = 0.870 +0.025-0.036 R_sun. The non-zero orbital eccentricity e = 0.054 +0.018-0.015 that we measure suggests that the planet underwent a massive tidal heating ~1 Gyr ago that could have contributed to its inflated radius. High-precision radial velocities obtained during a transit allow us to measure a sky-projected angle between the stellar spin and orbital axis Beta = 11 +14-18 deg. In addition to similar published measurements, this result favors a dominant migration mechanism based on tidal interactions with a protoplanetary disk.
description: submitted to A&A, 10 pages, 6 figures, 5 tables
New H2O masers in Seyfert and FIR bright galaxies. III. The Southern Sample
Creators: name: Surcis, G.
name: Tarchi, A.
name: Henkel, C.
name: Ott, J.
name: Lovell, J.
name: Castangia, P.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Recently, a relationship between the water maser detection rate and far infrared (FIR) flux densities has been established as a result of two 22 GHz maser surveys in a complete sample of galaxies (Dec>-30 degree) with 100 micron flux densities of > 50 Jy and > 30 Jy. This survey has been extended to the southern galaxies in order to discover new maser sources and to investigate the galaxies hosting the maser spots with particular emphasis on their nuclear regions. A sample of 12 galaxies with Dec50 Jy was observed with the 70-m telescope of the Canberra Deep Space Communication Complex (CDSCC) at Tidbinbilla (Australia) in a search for water maser emission. The average 3 sigma noise level of the survey is 15 mJy for a 0.42 km/s channel, corresponding to a detection threshold of ~0.1 solar luminosities for the isotropic maser luminosity at a distance of 25 Mpc. Two new detections are reported: a kilomaser with an isotropic luminosity L_H2O ~5 solar luminosities in NGC3620 and a maser with about twice this luminosity in the merger system NGC3256. The detections have been followed-up through continuum and spectral line interferometric observations with the Australia Telescope Compact Array (ATCA). In NGC3256, a fraction (about a third) of the maser emission arises from two hot spots associated with star formation activity, which are offset from the galactic nuclei of the system. The remaining emission may arise from weaker centers of maser activity distributed over the central 50 arcsec. [abridged]
description: 13 pages, 9 figures, accepted by Astronomy and Astrophysics
Dimensionless formulation and similarity to assess the main phenomena of heat and mass transfer in building porous material
Creators: name: Berger, Julien
name: Legros, Clemence
name: Abdykarim, Madina
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Applied Physics (physics.app-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Within the environmental context, several tools based on simulations have been proposed to analyze the physical phenomena of heat and mass transfer in porous materials. However, it is still an open challenge to propose tools that do not require to perform computations to catch the dominant processes. Thus, this article proposes to explore advantages of using a dimensionless analysis by scaling the governing equations of heat and mass transfer. Proposed methodology introduces dimensionless numbers and their nonlinear distortions. The relevant investigation enables to enhance the preponderant phenomena to \emph{(i)} compare different categories of materials, \emph{(ii)} evaluate the competition between heat and mass transfer for each material or \emph{(iii)} describe the transfer in multi-layered wall configurations. It also permits to define hygrothermal kinetic, geometric and dynamic similarities among different physical materials. Equivalent systems can be characterized in the framework of experimental or wall designs. Three cases are presented for similarity studies in terms of \emph{(i)} equivalent material length, \emph{(ii)} time of heat and mass transfer and \emph{(iii)} experimental configurations. All these advantages are illustrated in the given article considering $49$ building materials separated in $7$ categories.
The Einstein-Maxwell system in 3+1 form and initial data for multiple charged black holes
Creators: name: Alcubierre, Miguel
name: Degollado, Juan Carlos
name: Salgado, Marcelo
Publisher: name: arXiv
Year: 2009
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We consider the Einstein-Maxwell system as a Cauchy initial value problem taking the electric and magnetic fields as independent variables. Maxwell's equations in curved spacetimes are derived in detail using a 3+1 formalism and their hyperbolic properties are analyzed, showing that the resulting system is symmetric hyperbolic. We also focus on the problem of finding initial data for multiple charged black holes assuming time-symmetric initial data and using a puncture-like method to solve the Hamiltonian and the Gauss constraints. We study the behavior of the resulting initial data families, and show that previous results in this direction can be obtained as particular cases of our approach.
description: 20 pages, 6 figures, some typos fixed and references added
Concepts and Representational Format: The Structural Limits of Conceptual Representation
Creators: name: WILLIAMS, IWAN RHYS
Publisher: name: Monash University
Year: 2021
Subjects: subject: Philosophy
subject: FOS: Philosophy, ethics and religion

description: This thesis investigates what is required for a human or non-human animal to have concepts. It asks whether concepts require a particular kind of system of mental representations—a system that is akin to an internal language. It argues that a language-like system of representation is not necessary for having concepts, and that concepts can also occur in other sorts of representational systems, such as mental maps or diagrams. This conclusion is relevant to how we investigate whether a particular population—such as bees, chimps, or infant humans—has concepts.
Nanotechnology and Quasicrystals: From self assembly to photonic applications
Creators: name: Lifshitz, Ron
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: After providing a concise overview on quasicrystals and their discovery more than a quarter of a century ago, I consider the unexpected interplay between nanotechnology and quasiperiodic crystals. Of particular relevance are efforts to fabricate artificial functional micro- or nanostructures, as well as efforts to control the self-assembly of nanostructures, where current knowledge about the possibility of having long-range order without periodicity can provide significant advantages. I discuss examples of systems ranging from artificial metamaterials for photonic applications, through self-assembled soft matter, to surface waves and optically-induced nonlinear photonic quasicrystals.
description: Based on a talk given at the NATO Advanced Research Workshop on Nanotechnology in St. Petersburg (June 2008)
Maximally Non-Abelian Vortices from Self-dual Yang--Mills Fields
Creators: name: Manton, Nicholas S.
name: Sakai, Norisuke
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A particular dimensional reduction of SU(2N) Yang--Mills theory on $Σ\times S^2$, with $Σ$ a Riemann surface, yields an $S(U(N) \times U(N))$ gauge theory on $Σ$, with a matrix Higgs field. The SU(2N) self-dual Yang--Mills equations reduce to Bogomolny equations for vortices on $Σ$. These equations are formally integrable if $Σ$ is the hyperbolic plane, and we present a subclass of solutions.
description: 11 pages
Alloying effects on the optical properties of Ge$_{1-x}$Si$_x$ nanocrystals from TDDFT and comparison with effective-medium theory
Creators: name: Botti, Silvana
name: Weissker, Hans-Christian
name: Marques, Miguel A. L.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We present the optical spectra of Ge$_{1-x}$Si$_x$ alloy nanocrystals calculated with time-dependent density-functional theory in the adiabatic local-density ap proximation (TDLDA). The spectra change smoothly as a function of the compositio n $x$. On the Ge side of the composition range, the lowest excitations at the ab sorption edge are almost pure Kohn-Sham independent-particle HOMO-LUMO transitio ns, while for higher Si contents strong mixing of transitions is found. Within T DLDA the first peak is slightly higher in energy than in earlier independent-par ticle calculations. However, the absorption onset and in particular its composit ion dependence is similar to independent-particle results. Moreover, classical depolarization effects are responsible for a very strong suppression of the abs orption intensity. We show that they can be taken into account in a simpler way using Maxwell-Garnett classical effective-medium theory. Emission spectra are in vestigated by calculating the absorption of excited nanocrystals at their relaxe d geometry. The structural contribution to the Stokes shift is about 0.5 eV. Th e decomposition of the emission spectra in terms of independent-particle transit ions is similar to what is found for absorption. For the emission, very weak tra nsitions are found in Ge-rich clusters well below the strong absorption onset.
description: submitted to Phys. Rev. B
Frustration induced plateaux in S>=1/2 Heisenberg spin ladders
Creators: name: Michaud, F.
name: Coletta, T.
name: Manmana, S. R.
name: Picon, J. -D.
name: Mila, F.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We study the T = 0 magnetization of frustrated two-leg spin ladders with arbitrary value of the spin S. In the strong rung limit, we use degenerate perturbation theory to prove that frustration leads to magnetization plateaux at fractional values of the magnetization for all spins S, and to determine the critical ratios of parallel to diagonal inter-rung couplings for the appearance of these plateaux. These ratios depend both on the plateau and on the spin. To confirm these results, and to investigate the properties of these ladders away from the strong coupling limit, we have performed extensive density matrix renormalization group (DMRG) calculations for S <= 2. For large enough inter-rung couplings, all plateaux simply disappear, leading to a magnetization curve typical of integer-spin chains in a magnetic field. The intermediate region turns out to be surprisingly rich however, with, upon increasing the inter-rung couplings, the development of magnetization jumps and, in some cases, the appearance of one or more phase transitions inside a given plateau.
description: 11 pages, 8 figures,accepted for publication in Phys. Rev. B
BRITE. MOST. What is next?
Creators: name: Matthews, Jaymie
Publisher: name: Zenodo
Year: 2024

description: What facts do we still don't know about stars? Magnetism. How do star get the rotation - inside and in the interior. Convection. How does some stars - like roAp stars - pulsate? How do planets form around stars? Solar cycle: How does the Sun generate its periodically reversing large-scale magnetic field? How do other Sol-like stars generate their magnetic fields and what are the similarities and differences between stellar activity cycles and that of the Sun? Why is the magnetic reconnection effect many orders of magnitude faster than predicted by standard models? What is the origin of the stellar mass spectrum? Why do astronomers observe the same distribution of stellar masses — the initial mass function —- apparently regardless of the initial conditions? Massive stars. How far away are massive stars? What is a star’s mass? The only reliable method involves studying binary-star orbits. Can planets form around massive stars? Planets form from circumstellar disks of gas and dust. But how long can such disks survive around massive stars? Heavy stars exhaust their nuclear fuel in a few million years. Can planets form that fast? What role do rotation and magnetic fields play in massive stars? BRITE and MOST were examples of saying: (1) What problem about stars still exist and we are interested in? (2) What can we do from space with a small telescope or several telescopes? (3) How do we do it? Lets do it again.
CP violation and chiral symmetry restoration in the hot linear sigma model in a strong magnetic background
Creators: name: Mizher, Ana Júlia
name: Fraga, Eduardo S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the effects of CP violation on the nature of the chiral transition within the linear sigma model with two flavors of quarks. The finite-temperature effective potential containing contributions from nontrivial values for the parameter $θ$ is computed to one loop order and their minima structure is analyzed. Motivated by the possibility of observing the formation of CP-odd domains in high-energy heavy ion collisions, we also investigate the behavior of the effective potential in the presence of a strong magnetic background. We find that the nature of the chiral transition is influenced by both $θ$ and the magnetic field.
description: 8 pages, 9 figures
Measurement of the atmospheric muon flux with a 4 GeV threshold in the ANTARES neutrino telescope
Creators: name: ANTARES Collaboration
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: A new method for the measurement of the muon flux in the deep-sea ANTARES neutrino telescope and its dependence on the depth is presented. The method is based on the observation of coincidence signals in adjacent storeys of the detector. This yields an energy threshold of about 4 GeV. The main sources of optical background are the decay of 40K and the bioluminescence in the sea water. The 40K background is used to calibrate the efficiency of the photo-multiplier tubes.
description: 10 pages, 4 figures
BRITE Austria - A Catalyst for the Austrian Outer Space Act
Creators: name: Marboe, Irmgard
Publisher: name: Zenodo
Year: 2024

description: A national legal framework for outer space activities is required under international law, in particular under the Outer Space Treaty of 1967 and the Registration Convention of 1975 which Austria has ratified. Before BRITE-Austria, there was no urgent need for Austria to have a national space law, because it carried out the relevant activities in the framework of the European Space Agency. With the first launches of Austrian satellites into outer space, it needed to be ensured that these activities are authorized and continuosly supervised by Austria and that the satellites are registered in an Austrian registry and with the United Nations. The Austrian Outer Space Act of 2011 contains the legal basis for the authorities in Austria to comply with Austria's international obligations and to ensure that Austrian space activities are in conformity with Austrian national interests.
Magnetic Doping and Kondo Effect in Bi2Se3 Nanoribbons
Creators: name: Cha, Judy J.
name: Williams, James R.
name: Kong, Desheng
name: Meister, Stefan
name: Peng, Hailin
name: Bestwick, Andrew J.
name: Gallagher, Patrick
name: Goldhaber-Gordon, David
name: Cui, Yi
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: A simple surface band structure and a large bulk band gap have allowed Bi2Se3 to become a reference material for the newly discovered three-dimensional topological insulators, which exhibit topologically-protected conducting surface states that reside inside the bulk band gap. Studying topological insulators such as Bi2Se3 in nanostructures is advantageous because of the high surface-to-volume ratio, which enhances effects from the surface states; recently reported Aharonov-Bohm oscillation in topological insulator nanoribbons by some of us is a good example. Theoretically, introducing magnetic impurities in topological insulators is predicted to open a small gap in the surface states by breaking time-reversal symmetry. Here, we present synthesis of magnetically-doped Bi2Se3 nanoribbons by vapor-liquid-solid growth using magnetic metal thin films as catalysts. Although the doping concentration is less than ~ 2%, low-temperature transport measurements of the Fe-doped Bi2Se3 nanoribbon devices show a clear Kondo effect at temperatures below 30 K, confirming the presence of magnetic impurities in the Bi2Se3 nanoribbons. The capability to dope topological insulator nanostructures magnetically opens up exciting opportunities for spintronics.
description: 16 pages, 4 figures
High Quality Streaming Speech Synthesis with Low, Sentence-Length-Independent Latency
Creators: name: Ellinas, Nikolaos
name: Vamvoukakis, Georgios
name: Markopoulos, Konstantinos
name: Chalamandaris, Aimilios
name: Maniati, Georgia
name: Kakoulidis, Panos
name: Raptis, Spyros
name: Sung, June Sig
name: Park, Hyoungmin
name: Tsiakoulis, Pirros
Publisher: name: arXiv
Year: 2021
Subjects: subject: Sound (cs.SD)
subject: Computation and Language (cs.CL)
subject: Machine Learning (cs.LG)
subject: Audio and Speech Processing (eess.AS)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper presents an end-to-end text-to-speech system with low latency on a CPU, suitable for real-time applications. The system is composed of an autoregressive attention-based sequence-to-sequence acoustic model and the LPCNet vocoder for waveform generation. An acoustic model architecture that adopts modules from both the Tacotron 1 and 2 models is proposed, while stability is ensured by using a recently proposed purely location-based attention mechanism, suitable for arbitrary sentence length generation. During inference, the decoder is unrolled and acoustic feature generation is performed in a streaming manner, allowing for a nearly constant latency which is independent from the sentence length. Experimental results show that the acoustic model can produce feature sequences with minimal latency about 31 times faster than real-time on a computer CPU and 6.5 times on a mobile CPU, enabling it to meet the conditions required for real-time applications on both devices. The full end-to-end system can generate almost natural quality speech, which is verified by listening tests.
description: Proceedings of INTERSPEECH 2020
Multipartite bound entanglement and multi-setting Bell inequalities
Creators: name: Chi, Dong Pyo
name: Jeong, Kabgyun
name: Kim, Taewan
name: Lee, Kyungjin
name: Lee, Soojoon
Publisher: name: arXiv
Year: 2009
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Dür [Phys. Rev. Lett. {\bf 87}, 230402 (2001)] constructed $N$-qubit bound entangled states which violate a Bell inequality for $N\ge 8$, and his result was recently improved by showing that there exists an $N$-qubit bound entangled state violating the Bell inequality if and only if $N\ge 6$ [Phys. Rev. A {\bf 79}, 032309 (2009)]. On the other hand, it has been also shown that the states which Dür considered violate Bell inequalities different from the inequality for $N\ge 6$. In this paper, by employing different forms of Bell inequalities, in particular, a specific form of Bell inequalities with $M$ settings of the measuring apparatus for sufficiently large $M$, we prove that there exists an $N$-qubit bound entangled state violating the $M$-setting Bell inequality if and only if $N\ge 4$.
description: 4 pages, 2 figures
Comparison among Various Expressions of Complex Admittance for Quantum System in Contact with Heat Reservoir
Creators: name: Saeki, Mizuhiko
name: Uchiyama, Chikako
name: Mori, Takashi
name: Miyashita, Seiji
Publisher: name: arXiv
Year: 2009
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Relation among various expressions of the complex admittance for quantum systems in contact with heat reservoir is studied. Exact expressions of the complex admittance are derived in various types of formulations of equations of motion under contact with heat reservoir. Namely, the complex admittance is studied in the relaxation method and the external-field method. In the former method, the admittance is calculated using the Kubo formula for quantum systems in contact with heat reservoir in no external driving fields, while in the latter method the admittance is directly calculated from equations of motion with external driving terms. In each method, two types of equation of motions are considered, i.e., the time-convolution (TC) equation and time-convolutionless (TCL) equation. That is, the full of the four cases are studied. It is turned out that the expression of the complex admittance obtained by using the relaxation method with the TC equation exactly coincides with that obtained by using the external-field method with the TC equation, while other two methods give different forms. It is also explicitly demonstrated that all the expressions of the complex admittance coincide with each other in the lowest Born approximation for the systemreservoir interaction. The formulae necessary for the higher order expansions in powers of the system-reservoir interaction are derived, and also the expressions of the admittance in the n-th order approximation are given. To characterize the TC and TCL methods, we study the expressions of the admittances of two exactly solvable models. Each exact form of admittance is compared with the results of the two methods in the lowest Born approximation. It is found that depending on the model, either of TC and TCL would be the better method.
description: 34pages, no figure
Group Averaging for de Sitter free fields
Creators: name: Marolf, Donald
name: Morrison, Ian A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Perturbative gravity about global de Sitter space is subject to linearization-stability constraints. Such constraints imply that quantum states of matter fields couple consistently to gravity {\it only} if the matter state has vanishing de Sitter charges; i.e., only if the state is invariant under the symmetries of de Sitter space. As noted by Higuchi, the usual Fock spaces for matter fields contain no de Sitter-invariant states except the vacuum, though a new Hilbert space of de Sitter invariant states can be constructed via so-called group-averaging techniques. We study this construction for free scalar fields of arbitrary positive mass in any dimension, and for linear vector and tensor gauge fields in any dimension. Our main result is to show in each case that group averaging converges for states containing a sufficient number of particles. We consider general $N$-particle states with smooth wavefunctions, though we obtain somewhat stronger results when the wavefunctions are finite linear combinations of de Sitter harmonics. Along the way we obtain explicit expressions for general boost matrix elements in a familiar basis.
description: 33 pages, 2 figures