cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Evolving Newton's Constant, Extended Gravity Theories and SnIa Data Analysis
Creators: name: Nesseris, S.
name: Perivolaropoulos, L.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: If Newton's constant G evolves on cosmological timescales as predicted by extended gravity theories then Type Ia supernovae (SnIa) can not be treated as standard candles. The magnitude-redshift datasets however can still be useful. They can be used to simultaneously fit for both H(z) and G(z) (so that local G(z) constraints are also satisfied) in the context of appropriate parametrizations. Here we demonstrate how can this analysis be done by applying it to the Gold SnIa dataset. We compare the derived effective equation of state parameter w(z) at best fit with the corresponding result obtained by neglecting the evolution G(z). We show that even though the results clearly differ from each other, in both cases the best fit w(z) crosses the phantom divide w=-1. We then attempt to reconstruct a scalar tensor theory that predicts the derived best fit forms of H(z) and G(z). Since the best fit G(z) fixes the scalar tensor potential evolution F(z), there is no ambiguity in the reconstruction and the potential U(z) can be derived uniquely. The particular reconstructed scalar tensor theory however, involves a change of sign of the kinetic term $Φ'(z)^2$ as in the minimally coupled case.
description: Minor changes. Accepted in Phys. Rev. D. 7 revtex pages, 5 figures. The mathematica file with the numerical analysis of the paper is available at http://leandros.physics.uoi.gr/snevol.htm
Quantum phase transition in the multi-mode Dicke model
Creators: name: Tolkunov, Denis
name: Solenov, Dmitry
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: An investigation of the quantum phase transition in both discrete and continuum field Dicke models is presented. A series of anticrossing features following the criticality is revealed in the band of the field modes. Critical exponents are calculated. We investigate the properties of a pairwise entanglement measured by a concurrence and obtain analytical results in the thermodynamic limit.
description: 7 pages, 3 figures
Die DGWF-Jahrestagungen als Format für Wissensaustausch und Vernetzung. Eine Zeitreihenanalyse unter Berücksichtigung der aktuellen Evaluationsdaten der DGWF-Jahrestagung 2018 an der Technischen Hochschule Köln
Creators: name: Lobe, Claudia
name: Walber, Markus
Publisher: name: Zeitschrift Hochschule und Weiterbildung (ZHWB)
Year: 2019

description: Zeitschrift Hochschule und Weiterbildung (ZHWB), 2019/1: Formate der Hochschulweiterbildung
On the distribution of stellar masses in gamma-ray burst host galaxies
Creators: name: Cerón, J. M. Castro
name: Michałowski, M. J.
name: Hjorth, J.
name: Malesani, D.
name: Gorosabel, J.
name: Watson, D.
name: Fynbo, J. P. U.
name: Calderón, M. Morales
name: ;
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We analyse Spitzer images of 30 long-duration gamma-ray burst (GRB) host galaxies. We estimate their total stellar masses (M*) based on the rest-frame K-band luminosities (L_Krest) and constrain their star formation rates (SFRs, not corrected for dust extinction) based on the rest-frame UV continua. Further, we compute a mean M*/L_Krest = 0.45 Msun/Lsun. We find that the hosts are low M*, star-forming systems. The median M* in our sample ( = 10^9.7 Msun) is lower than that of "field" galaxies (e.g., Gemini Deep Deep Survey). The range spanned by M* is 10^7 Msun < M* < 10^11 Msun, while the range spanned by the dust-uncorrected UV SFR is 10^-2 Msun yr^-1 < SFR < 10 Msun yr^-1. There is no evidence for intrinsic evolution in the distribution of M* with redshift. We show that extinction by dust must be present in at least 25% of the GRB hosts in our sample and suggest that this is a way to reconcile our finding of a relatively lower UV-based, specific SFR (PHI = SFR/M*) with previous claims that GRBs have some of the highest PHI values. We also examine the effect that the inability to resolve the star-forming regions in the hosts has on PHI.
description: 10 pages by emulateApJ, 1 table and 5 figures (3 in colour); published in ApJ, main journal; version 3: new figure with postage stamps of IRAC/Spitzer images of each host, reverified photometry/astrometry
Forschung im Spannungsfeld von Erkenntnis- und Verwertungsinteresse Bericht zur 7. Forschungswerkstatt wissenschaftliche Weiterbildung der AG Forschung in der DGWF. 12. bis 13. April 2019 an der Otto-von-Guericke-Universität Magdeburg
Creators: name: Häßlich, Linda
Publisher: name: Zeitschrift Hochschule und Weiterbildung (ZHWB)
Year: 2019

description: Zeitschrift Hochschule und Weiterbildung (ZHWB), 2019/1: Formate der Hochschulweiterbildung
The impact of dipole straylight contamination on the alignment of low multipoles of CMB anisotropies
Creators: name: Gruppuso, A.
name: Burigana, C.
name: Finelli, F.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We estimate the impact of the Dipole Straylight Contamination (DSC) for the {\it Planck} satellite on the alignments of vectors associated to the low multipoles of the pattern of the cosmic microwave background (CMB) anisotropies. In particular we study how the probability distributions of eighteen estimators for the alignments change when DSC is taken into account. We find that possible residual DSC should leave a non-negligible impact on low multipole alignments for effective values of the fractional far sidelobe integrated response, $p$, larger than $\sim {\rm few} \times 10^{-3}$. The effect is strongly dependent on the intrinsic sky amplitude and weakly dependent on the considered scanning strategy. We find a decrease of the alignment probability between the quadrupole and the dipole and an increase of the alignment probability between the hexadecapole and the dipole (larger is the intrinsic sky amplitude and lower is the contamination). The remaining estimators do not exhibit clear signatures, except, in some cases, considering the largest values of $p$ and the lowest sky amplitudes. Provided that the real sidelobes of the {\it Planck} receivers in flight conditions will correspond to $p \lsim {\rm few} \times 10^{-3}$, as realistically expected at least in the cosmological frequency channels, and will be known with accuracies better than $\sim {\rm few} \times 10$% allowing for a suitable cleaning during data reduction, {\it Planck} will be very weakly affected from DSC on the alignments of low multipoles.
description: 13 pages, 14 figures, 1 table. To appear in MNRAS. Accepted 2007 January 10. Received 2006 January 09; in original form 2006 November 03. This work has been done in the framework of the Planck LFI activities
Theory of the isotropic-nematic transition in dispersions of compressible rods
Creators: name: Shundyak, K.
name: van Roij, R.
name: van der Schoot, P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We theoretically study the nematic ordering transition of rods that are able to elastically adjust their mutually excluded volumes. The model rods, which consist of a hard core surrounded by a deformable shell, mimic the structure of polymer-coated, rod-like fd virus particles that have recently been the object of experimental study [K.~Purdy et al., Phys. Rev. Lett. \textbf{94}, 057801 (2005)]. We find that fluids of such soft rods exhibit an isotropic-nematic phase transition at a density higher than that of the corresponding hard-rod system of identical diameter, and that at coexistence the order parameter of the nematic phase depends non monotonically on the elastic properties of the polymer coating. For binary mixtures of hard and soft rods, the topology of the phase diagram turns out to depend sensitively on the elasticity of shell. The lower nematic-nematic critical point, discovered in mixtures of bare and polymer-coated fd virus particles, is not reproduced by the theory.
description: 8 pages, 5 figures
Representations of integers as sums of primes from a Beatty sequence
Creators: name: Banks, William D.
name: Guloglu, Ahmet M.
name: Nevans, C. Wesley
Publisher: name: arXiv
Year: 2007
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11P32; 11B50

description: We study the problem of representing integers as sums of prime numbers from a fixed Beatty sequence $B_{α,β}$, where $α>1$ is irrational and of finite type.
description: 27 pages
The short periodic orbit method for excited chaotic eigenfunctions
Creators: name: Revuelta, F.
name: Vergini, E.
name: Benito, R. M.
name: Borondo, F.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: In this paper [published in Phys. Rev. E 102, 042210 (2020)], a new method for the calculation of excited chaotic eigenfunctions in arbitrary energy windows is presented. We demonstrate the feasibility of using wavefunctions localized on unstable periodic orbits as efficient basis sets for this task in classically chaotic systems. The number of required localized wavefunctions is only of the order of the ratio t H /t E , with t H the Heisenberg time and t E the Ehrenfest time. As an illustration, we present convincing results for a coupled two-dimensional quartic oscillator with chaotic dynamics.
description: 7 pages, 4 figures
On the strategy frequency problem in batch Minority Games
Creators: name: De Martino, A.
name: Castillo, I. Perez
name: Sherrington, D.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: Ergodic stationary states of Minority Games with S strategies per agent can be characterised in terms of the asymptotic probabilities $ϕ_a$ with which an agent uses $a$ of his strategies. We propose here a simple and general method to calculate these quantities in batch canonical and grand-canonical models. Known analytic theories are easily recovered as limiting cases and, as a further application, the strategy frequency problem for the batch grand-canonical Minority Game with S=2 is solved. The generalization of these ideas to multi-asset models is also presented. Though similarly based on response function techniques, our approach is alternative to the one recently employed by Shayeghi and Coolen for canonical batch Minority Games with arbitrary number of strategies.
description: 17 pages
The effect of flow on resonant absorption of slow MHD waves in magnetic flux tubes
Creators: name: Sadeghi, Mohammad
name: Bahari, Karam
name: Karami, Kayoomars
Publisher: name: arXiv
Year: 2021
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: In this paper, we study kink and sausage oscillations in the presence of longitudinal background flow. We study resonant absorption of the kink and sausage modes in the slow continuum under magnetic pore conditions in the presence of flow. we determine the dispersion relation then solve it numerically, and find the frequencies and damping rates of the slow kink and sausage surface modes. We also, obtain analytical solution for the damping rate of the slow surface mode in the long wavelength limit. We show that in the presence of plasma flow, resonance absorption can result in strong damping for forward waves and can be considered as an efficient mechanism to justify the extremely rapid damping of slow surface sausage waves observed in magnetic pores. Also, the plasma flow reduces the efficiency of resonance absorption to damp backward waves. Furthermore, for the pore conditions, the resonance instability is avoided in our model.
Improved Analysis of J/psi Decays into a Vector Meson and Two Pseudoscalars
Creators: name: Lähde, Timo A.
name: Meißner, Ulf-G.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Recently, the BES collaboration has published an extensive partial wave analysis of experimental data on J/psi -> phi pi+pi-, J/psi -> omega pi+pi-, J/psi -> phi K+K- and J/psi -> omega K+K-. These new results are analyzed here, with full account of detection efficiencies, in the framework of a chiral unitary description with coupled-channel final state interactions between pi-pi and K-bar K pairs. The emission of a dimeson pair is described in terms of the strange and nonstrange scalar form factors of the pion and the kaon, which include the final state interaction and are constrained by unitarity and by matching to the next-to-leading-order chiral expressions. This procedure allows for a calculation of the S-wave component of the dimeson spectrum including the f_0(980) resonance, and for an estimation of the low-energy constants of Chiral Perturbation Theory, in particular the large N_c suppressed constants L_4^r and L_6^r. The decays in question are also sensitive to physics associated with OZI violation in the 0++ channel. It is found that the S-wave contributions to phi pi+pi-, phi K+K- and omega pi+pi- given by the BES partial-wave analysis may be very well fitted up to a dimeson center-of-mass energy of ~1.2 GeV, for a large and positive value of L_4^r and a value of L_6^r compatible with zero. An accurate determination of the amount of OZI violation in the J/psi -> phi pi+pi- decay is achieved, and the S-wave contribution to omega K+K- near threshold is predicted.
description: 18 pages, 6 figures, title changed, accepted version for PRD
Azimuthal Asymmetries in DIS as a Probe of Intrinsic Charm Content of the Proton
Creators: name: Ananikyan, L. N.
name: Ivanov, N. Ya.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We calculate the azimuthal dependence of the heavy-quark-initiated ${\cal O}(α_{s})$ contributions to the lepton-nucleon deep inelastic scattering (DIS). It is shown that, contrary to the photon-gluon fusion (GF) component, the photon-quark scattering (QS) mechanism is practically $\cos2ϕ$-independent. We investigate the possibility to discriminate experimentally between the GF and QS contributions using their strongly different azimuthal distributions. Our analysis shows that the GF and QS predictions for the azimuthal $\cos2ϕ$ asymmetry are quantitatively well defined in the fixed flavor number scheme: they are stable, both parametrically and perturbatively. We conclude that measurements of the azimuthal distributions at large Bjorken $x$ could directly probe the intrinsic charm content of the proton. As to the variable flavor number schemes, the charm densities of the recent CTEQ and MRST sets of parton distributions have a dramatic impact on the $\cos2ϕ$ asymmetry in the whole region of $x$ and, for this reason, can easily be measured.
description: 22 pages, 8 figures, revtex4
Pionic contribution to relativistic Fermi Liquid parameters
Creators: name: Pal, Kausik
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We calculate pionic contribution to the relativistic Fermi Liquid parameters (RFLPs) using Chiral Effective Lagrangian. The RFLPs so determined are then used to calculate chemical potential, exchange and nuclear symmetry energies due to $π$$N$ interaction. We also evaluate two loop ring diagrams involving $σ$, $ω$ and $π$ meson exchanges and compare results with what one obtains from the relativistic Fermi Liquid theory (RFLT).
description: 6 pages, 2 figures, Published in Canadian Journal of Physics, vol. 88, issue 8, pp. 585-590
Timm C. Feld & Sabine Lauber-Pohle (Hrsg.). (2018). Organisation und Profession. Felder erwachsenenpädagogischer Forschung. Wiesbaden: Springer VS.
Creators: name: Damm, Christoph
Publisher: name: Zeitschrift Hochschule und Weiterbildung (ZHWB)
Year: 2019

description: Zeitschrift Hochschule und Weiterbildung (ZHWB), 2019/1: Formate der Hochschulweiterbildung
A maximum likelihood method for fitting colour-magnitude diagrams
Creators: name: Naylor, Tim
name: Jeffries, Rob
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present a maximum likelihood method for fitting two-dimensional model distributions to stellar data in colour-magnitude space. This allows one to include (for example) binary stars in an isochronal population. The method also allows one to derive formal uncertainties for fitted parameters, and assess the likelihood that a good fit has been found. We use the method to derive an age of 38.5 +3.5/-6.5 Myrs and a true distance modulus of 7.79 +0.11/-0.05 mags from the V vs V-I diagram of NGC2547 (the uncertainties are 67 percent confidence limits, and the parameters are insensitive to the assumed binary fraction). These values are consistent with those previously determined from low-mass isochronal fitting, and are the first measurements to have statistically meaningful uncertainties. The age is also consistent with the lithium depletion age of NGC2547, and the HIPPARCOS distance to the cluster is consistent with our value. The method appears to be quite general and could be applied to any N-dimensional dataset, with uncertainties in each dimension. However, it is particularly useful when the data are sparse, in the sense that both the typical uncertainties for a datapoint and the size of structure in the function being fitted are small compared with the typical distance between datapoints. In this case binning the data will lose resolution, whilst the method presented here preserves it. Software implementing the methods described in this paper is available from http://www.astro.ex.ac.uk/people/timn/tau-squared/.
description: 15 pages, 17 figures
title: Service Provision with autonomic characteristics in mesh environments
title: Παροχή υπηρεσιών με αυτόνομα χαρακτηριστικά σε δυναμικό περιβάλλον
titleType: AlternativeTitle
Creators: name: Gouvas, Panagiotis A.
Publisher: name: National Technological University of Athens
Year: 2011
Subjects: Αυτόνομα δίκτυα
Κατανεμημένοι Πίνακες Κατακερματισμού
Δυναμικά Δίκτυα
Δίκτυα ομότιμων κόμβων
Δυναμική δρομολόγηση
Autonomic Networks
Distributed Hash Tables
Mobile Networks
Ad-hoc networks
Peer to peer networks

description: 206 σ.
description: Η παρούσα διδακτορική διατριβή εστιάζει στο πεδίο των υπηρεσιών σε κινητούς ομότιμους κόμβους. Πιο συγκεκριμένα, στα πλαίσια της διατριβής προτείνεται μια αρχιτεκτονική και αναλύεται μια υλοποίηση ενός Κατανεμημένου Πίνακα Κατακερματισμού (Distributed Hash Table-DHT) η οποία είναι ικανή να λειτουργήσει χωρίς καμία κεντρικοποίηση.
description: This doctoral thesis focuses on the domain of mobile Peer-to-Peer applications and specifically it provides a Distributed Hash Table (DHT) architecture and implementation that is able to bootstrap and operate in Mesh Environments without any form of centralization.
Kanji no satori
Creators: name: Russell, Bruce David
Publisher: name: University of British Columbia
Year: 2009

description: A translation of the title would read the "wisdom of Chinese-Japanese characters". The growth of Asian language instruction in British Columbia public schools has witnessed an unprecedented number of students enrolled in Japanese as a second language classes. For students with no prior experience with Chinese script the Chinese-Japanese characters, or kanji, can prove to be a barrier that limits progress in the written instruction and learning of Japanese. Current teaching methods such as those from Japan may continue to be in popular usage, but educators in British Columbia need to acknowledge that given the differences between the Japanese teaching environment and our own, classrooms attempting to establish interest in Japanese as a language of study require techniques that allow for the student to invest in their own learning process, particularly given the distance from the target culture. While the kanji have been long perceived as extremely difficult to learn and appreciate, I propose through a personal narrative that the characters can be appreciated by more students when it is recognized that the setting of the Canadian classroom and the students in it, can become participants in the intermingling of two languages generally considered to be vastly different, yet as revealed by the etymology of the kanji have very much in common. As human constructs, these characters may be deconstructed by students who then reconsider the inherent meanings of the intertext, the internal structure, of the kanji. With an appreciation of the multilayered context of the symbol explored in a familiar language, students may then apply their acquired knowledge and skill into newer intercultural contexts of Japanese and English. My conviction is that the kanji are central to a personal exploration of Japan. The very nature of the characters as moving, timeless symbols of human interpretation was considered in this study, as was the inherent pedagogical quality of their etymological structure. This personalized research was concerned with the re-writing and re-learning of written Japanese for the North American learner. The question was one of equipping the Japanese as a second language learner with a new perspective that will enable them to use the innately human view of language revealed by the kanji. Commentators on linguistics and semiology such as Roland Barthes and Julia Kristeva were cited in probing the symbolic foundations of language, and our ability to play with meanings we so often take for granted in communicating our ideas. Exposing the hidden and unused meanings within the characters is described as a valuable contextual experience, and a method, in combination with other classroom approaches, of instilling motivation to learn the target language.
Bose Einstein Condensation of incommensurate solid 4He
Creators: name: Galli, D. E.
name: Reatto, L.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: It is pointed out that simulation computation of energy performed so far cannot be used to decide if the ground state of solid 4He has the number of lattice sites equal to the number of atoms (commensurate state) or if it is different (incommensurate state). The best variational wave function, a shadow wave function, gives an incommensurate state but the equilibrium concentration of vacancies remains to be determined. In order to investigate the presence of a supersolid phase we have computed the one--body density matrix in solid 4He for the incommensurate state by means of the exact Shadow Path Integral Ground State projector method. We find a vacancy induced Bose Einstein condensation of about 0.23 atoms per vacancy at a pressure of 54 bar. This means that bulk solid 4He is supersolid at low enough temperature if the exact ground state is incommensurate.
description: 5 pages, 2 figures
Analytic Results for Virtual QCD Corrections to Higgs Production and Decay
Creators: name: Aglietti, U.
name: Bonciani, R.
name: Degrassi, G.
name: Vicini, A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider the production of a Higgs boson via gluon-fusion and its decay into two photons. We compute the NLO virtual QCD corrections to these processes in a general framework in which the coupling of the Higgs boson to the external particles is mediated by a colored fermion and a colored scalar. We present compact analytic results for these two-loop corrections that are expressed in terms of Harmonic Polylogarithms. The expansion of these corrections in the low and high Higgs mass regimes, as well as the expression of the new Master Integrals which appear in the reduction of the two-loop amplitudes, are also provided. For the fermionic contribution, we provide an independent check of the results already present in the literature concerning the Higgs boson and the production and decay of a pseudoscalar particle.
description: 19 pages, 3 figures, version accepted by JHEP
Gernot Graeßner & Martin Hendrik Kurz (Hrsg.). (2018). Einführung in das Bildungs- und Kulturmanagement. Augsburg: Ziel-Verlag.
Creators: name: Schäfer, Erich
Publisher: name: Zeitschrift Hochschule und Weiterbildung (ZHWB)
Year: 2019

description: Zeitschrift Hochschule und Weiterbildung (ZHWB), 2019/1: Formate der Hochschulweiterbildung
การพัฒนาการจัดการเรียนรู้ตามรูปแบบการสืบเสาะที่ขับเคลื่อนด้วยกลวิธีการโต้แย้ง เพื่อส่งเสริมความสามารถในการคิดเชิงวิพากษ์ทางวิทยาศาสตร์ ของนักเรียนชั้นมัธยมศึกษาปีที่ 5 เรื่อง กรด-เบส
Creators: name: ธัญกมล ศักดิ์สูง
Publisher: name: หจก.เลิศศิลป์ สาส์ณ โฮลดิ้ง
Year: 2562
Subjects: การจัดการเรียนรู้ตามรูปแบบการสืบเสาะที่ขับเคลื่อนด้วยกลวิธีการโต้แย้ง, ความสามารถในการคิดเชิงวิพากษ์ทางวิทยาศาสตร์, กรด-เบส (Scientifically critical thinking ability, Argument-driven inquiry model, Acid-base)

description: วารสารชุมชนวิจัย มหาวิทยาลัยราชภัฏนครราชสีมา, 13, 2, 237-250
Exact mobility edges, $\mathcal{PT}$-symmetry breaking and skin effect in one-dimensional non-Hermitian quasicrystals
Creators: name: Liu, Yanxia
name: Wang, Yucheng
name: Liu, Xiong-Jun
name: Zhou, Qi
name: Chen, Shu
Publisher: name: arXiv
Year: 2020
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We propose a general analytic method to study the localization transition in one-dimensional quasicrystals with parity-time ($\mathcal{PT}$) symmetry, described by complex quasiperiodic mosaic lattice models. By applying Avila's global theory of quasiperiodic Schrödinger operators, we obtain exact mobility edges and prove that the mobility edge is identical to the boundary of $\mathcal{PT}$-symmetry breaking, which also proves the existence of correspondence between extended (localized) states and $\mathcal{PT}$-symmetry ($\mathcal{PT}$-symmetry-broken) states. Furthermore, we generalize the models to more general cases with non-reciprocal hopping, which breaks $\mathcal{PT}$ symmetry and generally induces skin effect, and obtain a general and analytical expression of mobility edges. While the localized states are not sensitive to the boundary conditions, the extended states become skin states when the periodic boundary condition is changed to open boundary condition. This indicates that the skin states and localized states can coexist with their boundary determined by the mobility edges.
description: 6 pages, 4 figures
Growth of balls of holomorphic sections and energy at equilibrium
Creators: name: Berman, Robert
name: Boucksom, Sebastien
Publisher: name: arXiv
Year: 2008
Subjects: subject: Complex Variables (math.CV)
subject: Algebraic Geometry (math.AG)
subject: Number Theory (math.NT)
subject: FOS: Mathematics

description: Let X be a compact complex manifold endowed with a big line bundle L. We define the energy at equilibrium of a weighted subset as the Monge-Ampere energy of the associated extremal plurisubharmonic weight. We prove the differentiability of the energy at equilibrium with respect to the weight, and show that this energy describes the asymptotic behaviour as k goes to infinity of the volume of the induced sup-norm unit ball in the space of global sections of kL. As a consequence of these results, we extend Rumely's Robin-type formula for the transfinite diameter. We also obtain an asymptotic description of the analytic torsion and extend Yuan's equidistribution theorem for algebraic points of small height to the case of a big line bundle.
description: 47 pages. Final version
Global dynamics of small solutions to the modified fractional Korteweg-de Vries and nonlinear Schrödinger equations
Creators: name: Saut, Jean-Claude
name: Wang, Yuexun
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: This paper concerns the modified fractional Korteweg-de Vries (modified fKdV) and nonlinear Schrödinger (modified fNLS) equations, with the dispersions |D|^α\partial_x and |D|^{α+1}, respectively. We prove the global existence of small solutions for both the Cauchy problems to the modified fKdV and fNLS equations, with a modified scattering which has a logarithmic phase correction. Our results cover the full range -1
Οι νομοθετικές αποφάσεις του κεφαλαίου VII του Χάρτη των Ηνωμένων Εθνών και ο ρόλος του Συμβουλίου Ασφαλείας ως παγκόσμιου νομοθέτη:
Creators: name: Τσιάπος, Αργύρης Θωμά
Publisher: name: Aristotle University of Thessaloniki
Year: 2010
Subjects: Συμβούλιο ασφαλείας
Παγκόσμια νομοθεσία
Τρομοκρατία, όπλα μαζικής καταστροφής
Security council
World legislation
Terrorism, weapons of mass destruction

description: Κατά πόσο το Συμβούλιο Ασφαλείας έχει αναδειχτεί σε παγκόσμιο νομοθέτη; Η σχετική συζήτηση ξεκίνησε δειλά τη δεκαετία του 1990, αλλά κορυφώθηκε τα τελευταία χρόνια με επίκεντρο κυρίως τις αποφάσεις 1373 και 1540 του Συμβουλίου Ασφαλείας. Η παρούσα εργασία φιλοδοξεί να καταγράψει τις κυριότερες απόψεις που έχουν διατυπωθεί πάνω στο ερώτημα αυτό, να ανιχνεύσει το γενικότερο ρόλο αλλά και τις ειδικότερες εξουσίες που νομιμοποιείται να ασκήσει το Συμβούλιο Ασφαλείας σύμφωνα με τον Καταστατικό Χάρτη του Οργανισμού Ηνωμένων Εθνών και, τέλος, να αναλύσει εκείνες τις αποφάσεις του Συμβουλίου Ασφαλείας, στις οποίες έχουν αποδοθεί νομοθετικά χαρακτηριστικά.
description: How much has the UN Security Council become the world legislator? The relative discussion began shyly during the 1990s, but climaxed in the past few years with epicentre mainly the UN SC resolutions 1373 and 1540. The current dissertation aims to record the main opinions that have been formulated on this question, to detect the general role as well as the special powers the Security Council is legitimized to practice according to the Constitutive Chart of the United Nations and, finally, to analyze those UN SC resolutions, in which have been attributed legislative characteristics.
Magnetic reconnections in the presence of three-dimensional magnetic nulls and quasi-separatrix layers
Creators: name: Kumar, Sanjay
name: Nayak, Sushree S.
name: Prasad, Avijeet
name: Bhattacharyya, Ramit
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: Three-dimensional (3D) magnetohydrodynamic simulations are carried out to explore magnetic reconnections in the presence of 3D magnetic nulls and quasi-separatrix layers (QSLs). The initial magnetic fields are created by superposing uniform vertical magnetic fields of two different magnitudes on a linear force-free field. The interior of the numerical box contains two 3D nulls with separatrix domes separated by a quasi-separator (or hyperbolic flux tube) with QSLs. In the first simulation, the uniform vertical field is so large that the nulls are located at low heights and the domes are separate. Initially unbalanced Lorentz forces drive rotational flows that form strong electric currents and strong torsional fan reconnection at the 3D nulls and weak QSL reconnection at the hyperbolic flux tube. Flipping or slipping of field lines is observed in both cases. In the second simulation, with a weaker vertical field and larger domes, the separatrix surfaces meet at the central quasi-separator and their rotation drives stronger QSL reconnection than before.
description: 24 pages, 14 figures, Accepted for the publication in Solar Physics
title: Μελέτη της δυναμικής οπτικών σολιτονικών σχηματισμών σε διατάξεις μέσων με μη εντοπισμένη, μη γραμμική συμπεριφορά
titleType: AlternativeTitle
title: Study of the dynamics of optical solitonic formations in nonlocal, nonlinear media
Creators: name: Papazisimos, Georgios N.
Publisher: name: National Technological University of Athens
Year: 2014
Subjects: Μη γραμμική διάδοση
Νηματικοί υγροί κρύσταλλοι
Σολιτόνια
Διακριτά συστήματα
Μη εντοπισμένη συμπεριφορά
Nonlinear propagation
Nematic liquid crystals
Solitons
Discrete systems
Nonlocality

description: 143 σ.
description: Τα διακριτά προβλήματα αποτελούν ένα μεγάλο κομμάτι της έρευνας στη μη γραμμική οπτική. Στην παρούσα διατριβή εξετάζονται τέτοια προβλήματα (1+1 και 2+1), σε υλικά που εμφανίζουν έντονα μη εντοπισμένη συμπεριφορά. Διατυπώνονται κατάλληλες εξισώσεις για να περιγράψουν τις υποκείμενες φυσικές διεργασίες και χρησιμοποιούνται κατάλληλες αναλυτικές και αριθμητικές μέθοδοι για την επίλυσή τους. Η εργασία σκοπό έχει να μοντελοποιήσει την οπτική διάδοση, να διερευνήσει τη δυναμική των σχετικών συστημάτων και να αναζητήσει περιοχές παραμέτρων που υποστηρίζουν εντοπισμένες σολιτονικές λύσεις, οι οποίες και αποτελούν, μαζί με τη δυνατότητα δρομολόγησης και ελέγχου, ζητούμενο για πιθανές τεχνολογικές εφαρμογές.
description: Discrete problems are a major part of research in nonlinear optics. In the present dissertation such problems (1+1 and 2+1) are studied in media, which exhibit non-local behavior. The relevant equations, describing the underlying physical processes, are presented and suitable analytical and numerical methods for their solution of the equations are employed. The work is aimed at modeling the optical propagation, examining the dynamics of the relevant systems and investigating parameter regions, which support solitonic solutions, which along with the possibilities for steering and control are sought for prospective technological applications
Effect of Malaria and HIV co-infection on Haematological Indices among HIV patients attending the Antiretroviral Clinic at Cité Verte District Hospital in Yaounde, Cameroon
Creators: name: Niba, Peter Thelma Ngwa
name: Tsiambom Monju
name: Akindeh Mbuh Nji
name: Ali, Innocent Mbulli
name: Piameu, Michael
name: Mbacham, Wilfred Fon
Publisher: name: AAS Open Research
Year: 2019

description: Objectives: To determine the effect of malaria and Human Immunodeficiency Virus (HIV) co-infection on haematological indices among HIV patients attending the Antiretroviral Clinic at Cité Verte District Hospital in Yaounde, Cameroon.
Methods: A cross sectional study was adopted from November to December, 2018. A total of 289 HIV patients were recruited to take part in the study. Venous blood was collected to detect the malaria parasite and measure blood parameters.
Results: Out of the 289 individuals who took part in the study, there were more females 207 (71.6%) compared to males 82 (28.4%). The prevalence of malaria and HIV co-infection was 73 (25.3%). There was a significant difference of haemoglobin concentration, mean cell volume, mean cell haemoglobin and mean cell haemoglobin concentration between malaria/HIV co-infected patients and HIV patients with no malaria. However, there was no significant difference of white blood cell count or red blood cell count between malaria/HIV co-infected patients and HIV patients with no malaria.
Conclusions: We reported a high prevalence of malaria among HIV patients. The findings from this study showed that malaria and HIV co-infection had a significant reduction on red cell indices with no effect on white or red blood cell counts.
Conceptualisation and specifications of a social networking platform for educational purposes:
Creators: name: Παπαδοπούλου, Καλλιόπη Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2010
Subjects: Πλατφόρμα κοινωνικής δικτύωσης
Εκπαίδευση
Λειτουργικές απαιτήσεις
Social networking platform
Education
Requirements

description: Στην παρούσα μελέτη αναλύουμε τις προδιαγραφές για την κατασκευή πλατφόρμας κοινωνικής δικτύωσης, η οποία αποσκοπεί να βοηθήσει τη μάθηση, τη διδασκαλία και την αξιολόγηση. Η έννοια της κοινωνικής δικτύωσης χρησιμοποιείται εκτενώς σήμερα, αλλά η ίδια ευρεία χρήση δεν έχει παρατηρηθεί από εκπαιδευτικής απόψεως. Υπάρχουν ισχυρές ενδείξεις ότι η συμπερίληψη εργαλείων κοινωνικής δικτύωσης στα πλαίσια της τυπικής και άτυπης μάθησης μπορεί να έχει ευεργετικά αποτελέσματα στη διαδικασία της μάθησης. Παρ’όλα αυτά, έρευνες έχουν δείξει επίσης ότι υπάρχει ένας βαθύς σκεπτικισμός για το εάν οι πλατφόρμες κοινωνικής δικτύωσης ενισχύουν πραγματικά την μάθηση ή την εμποδίζουν. Η κύρια υπόθεση της παρόυσας έρευνας είναι πώς μπορούμε να περιγράψουμε τις λειτουργικές απαιτήσεις ενός εκπαιδευτικού κοινωνικού δικτύου, έτσι ώστε να ενσωματώνει τις θετικές πτυχές της κοινωνικής δικτύωσης με σταθερές παιδαγωγικές βάσεις. Συγχρόνως, η σχεδίαση γίνεται με την απαραίτητη προσοχή, έτσι ώστε να ωφελήσει πραγματικά τη μάθηση και όχι να την aποτρέψει.
description: In the present project we analyse the specifications for the construction of a social networking platform for learning, teaching and testing. The social networking notion is a trend used extensively nowadays, but the same wide usage has not been observed in terms of education. There are strong indications that using social networking tools to improve formal and informal learning has beneficial effects for the learning process. On the other hand, research has also shown that there is a profound scepticism whether social networking platforms actually enhance learning or obstruct it. The main hypothesis is to what extent a dedicated educational social network’s functionalities could be specified, so that it would integrate the positive aspects of social networking with a solid pedagogical background. At the same time, the specification is done with extreme caution, so that it will truly augment and facilitate learning and not hinder it.
Rotavirus genomics pre- and post-vaccine introduction in Kenya to infer virus sources, transmission patterns and vaccine impact
Creators: name: Agoti, Charles
name: M.  Mwanga
name: R.  Njeru
name: M.V.T.  Phan
name: M.  Cotten
name: E.C.  Holmes
name: D. J.  Nokes
Publisher: name: AAS Open Research
Year: 2019

description: Objectives. To investigate (a) the viral factors underlying the reduced efficacy of RVA vaccines in Kenya (b) the underlying mechanisms by which RVA strains persist in local populations to cause epidemics year-in year-out, in particular as circulation decreases as a result of vaccine coverage.
Methods. We are undertaking a detailed genotype and full-length genome sequence analysis of RVA isolates detected at Kilifi County Hospital, Coastal Kenya, since 2010.
Results. We have observed a decline in prevalence of RVA in children admitted with AGE in the hospital from 23.8% pre-vaccine to 17.3% post-vaccine introduction in Kenya. Isolate typing from partial genomes indicate persistence of some genotypes from pre-to-post vaccine era. Surprisingly, the wildtype strain that is genetically homologous to the vaccine strain has continued to dominate local epidemics. Full viral genomes have been generated for 191 samples pre-vaccine samples.
Conclusions. The epidemiology of rotavirus strains circulating in Kenya is changing with some genetic types showing longer-term persistence while others have disappeared. Analysis of the full genomes may illuminate further on local epidemiology and improve understanding on why rotavirus vaccines don’t work optimally in developing countries.
Increased Mortality in Children with Neurological Impairments in Rural Kenya
Creators: name: J.A Abuga
name: S.M Kariuki
name: S.M Kinyanjui
name: M.B Van Hensbroek
name: C.R Newton
Publisher: name: AAS Open Research
Year: 2019

description: This study aims at comparing the risk of death in children with impairment of the nervous system with children without impairment, and to identify risk factors and causes of death. Children aged 6-9 years were diagnosed for impairment of the nervous system in a survey conducted in 2001. All children from the survey were observed until death or end of the follow-up study. Statistical analyses estimated the death rates, risk factors and causes of death. The death rates in children with impairment were 6 times higher than in children without impairment. Age and sex differences did not influence the risk of death in children with impairment of the nervous system. Among children with impairment, the risk of death was increased by developmental delay and reduced by better nutritional status. Infections such as HIV/AIDS common among all children who died. The risk of death was significantly higher in children with impairment of the nervous system. While developmental delay was associated with increased the risk of death in affected children, better nutritional status was associated with a reduced risk.
A structure-function analysis of the complex gene, bli-4, caenorhabditis elegans
Creators: name: Srayko, Martin Anthony
Publisher: name: University of British Columbia
Year: 2009

description: The purpose of this study was to elucidate the relationship between the molecular structure of bli-4 in Caenorhabditis elegans and the functional role of the predicted proteins produced by this complex gene. En route to this goal, the molecular structure of bli-4 has been redefined at the 5' and 3' ends of the gene; bli-4 is trans-spliced to the leader sequence SL1 and encodes 21 exons. Two approaches were adopted to study the relationship between the predicted BLI-4 products and bli-4 mutations. The first employs a systematic search through a portion of the gene in five bli-4 mutant strains using PCRbased heteroduplex analysis. The second approach utilized the technique of germline transformation rescue with injected plasmid DNA. Minigenes, or clones of D N A that contain information necessary to encode a subset of the predicted isoforms of the gene, were constructed for this latter approach. The minigene rescue experiments provide a direct test for the capacity of a given isoform to rescue the different phenotypes of bli-4 (i.e., blistering and/or lethality). One allele, hl99, was detected in the 5' end of the gene as a polymorphism using the PCR-based heteroduplex technique. DNA sequence from homozygous arrested larvae indicated that hl99 is the result of a missense mutation, changing a histidine residue to leucine. This amino acid substitution is in the amino terminus, proximal to the protease domain, and in a region that is not particularly well conserved among kex2/subtilisin-like family members. Genetic analysis suggests that the BLI-4 gene products provide at least two distinct functions: one, which when removed, gives rise to blisters, and the other, which when removed, results in death. Data from transgenic minigene experiments, however, suggest that the structures of the isoforms are sufficiently similar to be functionally redundant. In light of this new data, it is likely that functional distinction between the bli-4 isoforms is due to pre post-translational localization and that either or both of these mechanisms are overridden by exogenous copies of minigenes that encode a subset of the total products of bli-4.
title: Οπτικές υποδομές Δικτύων Πρόσβασης Νέας Γενιάς: Στρατηγικές Δημοτικής Ανάμειξης
titleType: AlternativeTitle
title: Fiber optic infrastructures for Next Generation Access Networks: Strategies for Municipal Intervention
Creators: name: Troulos, Costas I.
Publisher: name: National Technological University of Athens
Year: 2013
Subjects: Δίκτυα Πρόβασης Νέας Γενιάς
Δημόσια πολιτική
Τηλεπικοινωνίες
FTTH
Δημόσια παρέμβαση
Επιχειρηματική στρατηγική
Επιχειρηματικά μοντέλα
Next Generation Access Networks
Public policy
Telecommunications
Public intervention
Business strategy
Business models

description: 234 σ.
description: Η δημοτική ευρυζωνικότητα αποτελεί έναν από τους κυρίαρχους μοχλούς ανάπτυξης των οπτικών υποδομών πρόσβασης στην Ευρώπη. Οι δήμοι που έμεσα ή άμεσα εμπλέκονται στην ανάπτυξη δικτύων FTTH στην Ευρώπη υπολογίζονται ήδη σε μερικές χιλιάδες. Η παρούσα διατριβή επικεντρώνεται στις περιπτώσεις δημοτικής ευρυζωνικότητας στην Ευρώπη και εξετάζει τρόπους με τους οποίους η εμπειρία αυτή μπορεί να χρησιμεύσει ως οδηγός για πολιτικές δημόσιας ανάμειξης σε αναδυόμενες αγορές. Προκειμένου να επιβεβαιώσουμε τις παραδοχές και συμπεράσματα για τη δημοτική ευρυζωνικότητα επιλέξαμε συγκεκριμένα προφιλ περιοχών στην Στερεά Ελλάδα και αξολογήσαμε συγκεκριμένα σενάρια ανάπτυξης. Η αξιολόγηση αφορά σε εκτιμήσεις για κοστοστρεφή τιμολόγηση υπηρεσιών και στις επιπτώσεις στη βιωσιμότητα των δημοτικών δικτύων FTTH των εξής παραμέτρων: (i) μέσο έσοδο ανά χρηστη, (ii) βαθμός διείσδυσης και (iii) κατασκευή σε φάσεις. Βάσει τον συμπερασμάτων μας, προτείνουμε ένα επιχειρηματικό μοντέλο για την δημοτική ανάμειξης στις Ελληνικές περιφέρειες.
description: Municipal broadband is one of the leading drivers of growth for the optical access infrastructure market in Europe. The municipalities that are currently directly or indirectly involved in FTTH development across Europe are already in the order of thousands. This dissertation focuses on municipal broadband use cases in Europe and examines ways that this experience could provide guidance on intervention policies in emerging markets. In order to benchmark the business case of municipal broadband, we selected specific profiles in a Greek region (Sterea Ellada) and assessed specific deployment scenarios. Our assessment involved estimations of cost-oriented pricing and the impact of (i) average revenue per user, (ii) penetration rates, and (iii) staged development on the sustainability of a municipal FTTH business case. Based on our findings, we suggest a business model for municipal intervention applicable to the case of Greek provinces.
Enhancing stakeholders’ capacity in improving hygiene and safety in the beef value chain in the Ashaiman municipality, Ghana
Creators: name: V.Y.  Adjei
name: K.K.  Addo
name: K. Tano-Debrah
name: A.  Parry-Hanson
name: G.I.  Mensah
Publisher: name: AAS Open Research
Year: 2019

description: Objective: To investigate the quality and safety of beef and to assess stakeholders’ knowledge and practices to improve hygiene and safety within the beef value chain.
Methodology: Eighty raw beef samples from slaughterhouses and retail shops were analysed between June 2014 and January 2015. Prevalence of specific pathogens including Salmonella species, Listeria monocytogenes, Brucella species, Cryptosporidium parvum, Toxoplasma gondii and Cyclospora cayetenensis were determined using standard methods. Data regarding knowledge and practices were collected and observed from 115 stakeholders to determine practices that impact on beef safety.
Results: Salmonella typhimurium was isolated from 7.5% (6/80) of total sample. Mean level of microbial contamination of beef from slaughterhouses (5.9 Log10 CFU/g) was not significantly different (p=0.58) from levels observed at retail points (6.3 Log10 CFU/g). Mean faecal coliform counts of 4.1 Log10 CFU/g and 4.6 Log10 CFU/g recorded at slaughterhouses and retail shops, respectively exceeded the limits of 4 Log10 CFU/g required by the Ghana Standard Authority for meat safety. The percentage score on knowledge on food safety was 55.3% for butchers and 57.6 % for retailers.
Conclusion: Poor hygiene practices and poor sanitary conditions at the abattoirs and retail shops observed are likely to be the main factors contributing to the microbial contamination of raw beef.