cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Sentence Comprehension Deficits of Specific Language Impairment (Montgomery et al., 2016)
Creators: name: Montgomery, James W.
name: Gillam, Ronald B.
name: Evans, Julia L.
Publisher: name: ASHA journals
Year: 2022
Subjects: Child language acquisition
Natural language processing

description: Purpose: Compared with same-age typically developing peers, school-age children with specific language impairment (SLI) exhibit significant deficits in spoken sentence comprehension. They also demonstrate a range of memory limitations. Whether these 2 deficit areas are related is unclear. The present review article aims to (a) review 2 main theoretical accounts of SLI sentence comprehension and various studies supporting each and (b) offer a new, broader, more integrated memory-based framework to guide future SLI research, as we believe the available evidence favors a memory-based perspective of SLI comprehension limitations. Method: We reviewed the literature on the sentence comprehension abilities of English-speaking children with SLI from 2 theoretical perspectives. Results: The sentence comprehension limitations of children with SLI appear to be more fully captured by a memory-based perspective than by a syntax-specific deficit perspective. Conclusions: Although a memory-based view appears to be the better account of SLI sentence comprehension deficits, this view requires refinement and expansion. Current memory-based perspectives of adult sentence comprehension, with proper modification, offer SLI investigators new, more integrated memory frameworks within which to study and better understand the sentence comprehension abilities of children with SLI.
Prospects for cooling nanomechanical motion by coupling to a superconducting microwave resonator
Creators: name: Teufel, J. D.
name: Regal, C. A.
name: Lehnert, K. W.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Recent theoretical work has shown that radiation pressure effects can in principle cool a mechanical degree of freedom to its ground state. In this paper, we apply this theory to our realization of an opto-mechanical system in which the motion of mechanical oscillator modulates the resonance frequency of a superconducting microwave circuit. We present experimental data demonstrating the large mechanical quality factors possible with metallic, nanomechanical beams at 20 mK. Further measurements also show damping and cooling effects on the mechanical oscillator due to the microwave radiation field. These data motivate the prospects for employing this dynamical backaction technique to cool a mechanical mode entirely to its quantum ground state.
description: 6 pages, 6 figures
Interface Yang-Mills, Supersymmetry, and Janus
Creators: name: D'Hoker, Eric
name: Estes, John
name: Gutperle, Michael
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We consider theories consisting of a planar interface with $\N=4$ super-Yang-Mills on either side and varying gauge coupling across the interface. The interface does not carry any independent degrees of freedom, but is allowed to support local gauge invariant operators, included with independent interface couplings. In general, both conformal symmetry and supersymmetry will be broken, but for special arrangements of the interface couplings, these symmetries may be restored. We provide a systematic classification of all allowed interface supersymmetries. We find new theories preserving eight and four Poincaré supersymmetries, which get extended to sixteen and eight supersymmetries in the conformal limit, respectively with $SU(2) \times SU(2)$, $SO(2) \times SU(2)$ internal symmetry. The Lagrangians for these theories are explicitly constructe d. We also recover the theory with two Poincaré supersymmetries and SU(3) internal symmetry proposed earlier as a candidate CFT dual to super Janus. Since our new interface theories have only operators from the supergravity multiplet turned on, dual supergravity solutions are expected to exist. We speculate on the possible relation between the interface theory with maximal supersymmetry and the near-horizon limit of the D3-D5 system.
description: 37 pages, 1 figure, LaTeX
Bernstein-Szegő measures on the two dimensional torus
Creators: name: Knese, Greg
Publisher: name: arXiv
Year: 2007
Subjects: subject: Functional Analysis (math.FA)
subject: Classical Analysis and ODEs (math.CA)
subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 42C05, 30E05, 47A57

description: We present a new viewpoint (namely, reproducing kernels) and new proofs for several recent results of J. Geronimo and H. Woerdeman on orthogonal polynomials on the two dimenional torus (and related subjects). In addition, we show how their results give a new proof of Ando's inequality via an equivalent version proven by Cole and Wermer. A simple necessary and sufficient condition for two variable polynomial stability is also given.
description: Changed title to match published version
Farmers, Cooperatives, and USDA: A History of Agricultural Cooperative Service
Creators: name: Rasmussen, Wayne D.
name: Rasmussen, Wayne D.
Publisher: name: Unknown
Year: 1991
Subjects: subject: Agribusiness
subject: Agricultural and Food Policy
subject: Marketing
subject: FOS: Economics and business

description: Excerpts from the report Preface: July 2, 1991, marks the 65th anniversary of passage of the Cooperative Marketing Act of 1926. This act recognizes cooperative marketing as an implicit part of the Nation's policy prescription for assisting producers of agricultural products to deal with issues facing them. Some of the momentum supporting this approach was altered in the Depression of the 1930's when farm programs were initiated to address a number of the same problems. The Department's role in assisting producers and other rural residents to engage in self-help activity is worth documenting at this juncture. It demonstrates how a relatively small program, by Federal standards, has had a significant impact on improving farm incomes and market efficiency. Cooperation takes on an increasingly important role as independent farmers face a marketplace characterized by more integration, coordination, and interdependence. Readers should glean from this book how a governmental service-oriented program can augment a stronger and more prosperous production agriculture and rural America.
Creatività immaginativa e radicamento riproduttivo in Paul Ricoeur
Creators: name: Colleoni, Alessandro
Publisher: name: ACME
Year: 2019

description: Le analisi che Paul Ricoeur ha dedicato alla tematica dell’immaginazione propongono una netta distinzione tra la sua dimensione produttiva e quella riproduttiva, di esplicita derivazione kantiana. Tale divaricazione sembra portare in alcuni testi all’identificazione della prima con il solo ambito linguistico e della seconda con ogni situazione che implichi un legame tra immaginazione e materiale percettivo, il che significherebbe abbandonare la prospettiva fenomenologica a favore di una visione unicamente ermeneutica. Sulla base di una proposta di stampo fenomenologico che cerca di superare questo divario, si propone una rilettura degli studi ricoeuriani sulla metafora e di quelli sul racconto individuando in particolare in questi ultimi una serie di elementi che vanno in questa stessa direzione.
description: ACME, V. 71, N. 2 (2018)
Multiresolution surface construction for hierarchical B-splines
Creators: name: Wong, David
Publisher: name: University of British Columbia
Year: 2009

description: This thesis presents a method for automatically generating a hierarchical B-spline surface suitable for animation and interactive modification from an initial set of control points. Given an existing mesh M[sup k+1] of control points, a mesh with half the resolution M[sup k+1], is constructed by simultaneously approximating the finer mesh and minimizing a smoothness or fairness constraint using weighted least squares. The membrane and thin plate models have been tried as smoothness constraints. Various numerical solving techniques have also been tested. Curvature measures of M[sup k+1] are used to identify features that need only be represented in the finer mesh. Some hierarchical B-spline surfaces, a B-spline surface and a digitized surface have been tested by this method. The resulting hierarchical surface generated accurately and economically reproduces the original mesh, is free from excessive undulations in the intermediate levels, and is well behave for editing and animation.
On the production of flat electron bunches for laser wake field acceleration
Creators: name: Kando, M.
name: Fukuda, Y.
name: Kotaki, H.
name: Koga, J.
name: Bulanov, S. V.
name: Tajima, T.
name: Chao, A.
name: Pitthan, R.
name: Schuler, K. -P.
name: Zhidkov, A. G.
name: Nemoto, K.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: We suggest a novel method for injection of electrons into the acceleration phase of particle accelerators, producing low emittance beams appropriate even for the demanding high energy Linear Collider specifications. In this paper we work out the injection into the acceleration phase of the wake field in a plasma behind a high intensity laser pulse, taking advantage of the laser polarization and focusing. With the aid of catastrophe theory we categorize the injection dynamics. The scheme uses the structurally stable regime of transverse wake wave breaking, when electron trajectory self-intersection leads to the formation of a flat electron bunch. As shown in three-dimensional particle-in-cell simulations of the interaction of a laser pulse in a line-focus with an underdense plasma, the electrons, injected via the transverse wake wave breaking and accelerated by the wake wave, perform betatron oscillations with different amplitudes and frequencies along the two transverse coordinates. The polarization and focusing geometry lead to a way to produce relativistic electron bunches with asymmetric emittance (flat beam). An approach for generating flat laser accelerated ion beams is briefly discussed.
description: 29 pages, 5 figures
Caustics in quantum many-body dynamics
Creators: name: Kirkby, W.
name: Yee, Y.
name: Shi, K.
name: O'Dell, D. H. J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We describe a new class of nonequilibrium quantum many-body phenomena in the form of networks of caustics that dominate the many-body wavefunction in the semiclassical regime following a sudden quench. It includes the light cone-like propagation of correlations as a particular case. Caustics are singularities formed by the birth and death of waves and form a hierarchy of universal patterns whose natural mathematical description is via catastrophe theory. Examples in classical waves range from rainbows and gravitational lensing in optics to tidal bores and rogue waves in hydrodynamics. Quantum many-body caustics are discretized by second-quantization (``quantum catastrophes'') and live in Fock space which can potentially have many dimensions. We illustrate these ideas using the Bose Hubbard dimer and trimer models which are simple enough that the caustic structure can be elucidated from first principles and yet run the full range from integrable to nonintegrable dynamics. The dimer gives rise to discretized versions of fold and cusp catastrophes whereas the trimer allows for higher catastrophes including the codimension-3 hyperbolic and elliptic umbilics which are organized by, and projections of, an 8-dimensional corank-2 catastrophe known as $X_9$. These results describe a hitherto unrecognized form of universality in quantum dynamics organized by singularities that manifest as strong fluctuations in mode population probabilities.
description: 30 pages, 20 figures
Effects of new leptons in Electroweak Precision Data
Creators: name: del Aguila, F.
name: de Blas, J.
name: Perez-Victoria, M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We obtain limits on generic vector-like leptons at the TeV scale from electroweak precision tests. These limits are complementary to the ones obtained from lepton flavour violating processes. In general, the quality of the global electroweak fit is comparable to the one for the Standard Model. In the case of an extra neutrino singlet mixing with the muon or electron, the global fit allows for a relatively large Higgs mass (M_H < 260 GeV at 90 % C.L.), thus relaxing the tension between the direct LEP limit and the Standard Model fit.
description: 33 pages, 24 figures; updated with new m_t value, with minor changes. Extra references
Analyzing Novel Grant-Based and Grant-Free Access Schemes for Small Data Transmission
Creators: name: Zhou, Hui
name: Deng, Yansha
name: Feltrin, Luca
name: Höglund, Andreas
Publisher: name: arXiv
Year: 2021
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Fifth Generation (5G) New Radio (NR) does not support data transmission during random access (RA) procedures, which results in unnecessary control signalling overhead and power consumption, especially for small data transmission (SDT). Motivated by this, 3GPP has proposed 4/2-step SDT RA schemes based on the existing grant-based (4-step) and grant-free (2-step) RA schemes, with the aim to enable data transmission during RA procedures in Radio Resource Control (RRC) Inactive state. To compare the 4/2-step SDT RA schemes with the benchmark 4/2-step RA schemes, we provide a spatio-temporal analytical framework to evaluate the RA schemes, which jointly models the preamble detection, Physical Uplink Shared Channel (PUSCH) decoding, and data transmission procedures. Based on this analytical model, we derive the analytical expressions for the overall packet transmission success probability and average throughput in each RACH attempt. We also derive the average energy consumption in each RACH attempt. Our results show that 2-step SDT RA scheme provides the highest overall packet transmission success probability, and the lowest average energy consumption, but the performance gain decreases with the increase of device intensity.
title: Plasma polymerization of biogenic precursors
Creators: name: Loesch‐Zhang, Amelia
name: Geissler, Andreas
name: Biesalski, Markus
Publisher: name: Wiley-VCH
Year: 2024

description: Plasma‐enhanced chemical vapor deposition is a highly promising tool for coating deposition due to its versatility, tunability, low chemical consumption, and cost‐effectiveness, with an increasing scope of deposition methods at both low and atmospheric pressure. Adhering to green chemistry principles, biobased precursors have recently shifted into the focus of research interests. This review gives an overview of the main biogenic substance classes that have been used for the deposition of plasma polymer coatings, including natural oils, terpenes, enzymes, and lactic acid‐based precursors. The common feature of these precursors is not only their biogenic origin, but additionally the manifold properties of the resulting plasma‐deposited thin films, ranging from antimicrobial properties to tunable surface‐wetting characteristics, electrical conductivity, or biodegradability. This combination of unique features makes plasma‐derived polymers based on natural precursors immensely attractive for manifold applications.
Breaking strong symmetries in dissipative quantum systems: Bosonic atoms coupled to a cavity
Creators: name: Halati, Catalin-Mihai
name: Sheikhan, Ameneh
name: Kollath, Corinna
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In dissipative quantum systems, strong symmetries can lead to the existence of conservation laws and multiple steady states. In this work we investigate a strong symmetry for bosonic atoms coupled to an optical cavity, an experimentally relevant system, generalizing the adiabatic elimination techniques and using numerically exact matrix product state methods. We show that for ideal bosons coupled to the cavity multiple steady states exist and in each symmetry sector a dissipative phase transition occurs at a different critical point. This implies that phases of very different nature can coexist. We find that the introduction of a slight breaking of the strong symmetry by a small interaction term leads to a direct transition from multiple steady states to a unique steady state. We point out the phenomenon of dissipative freezing, the breaking of the conservation law at the level of individual realizations in the presence of the strong symmetry. For a small breaking of the strong symmetry we see that the behavior of the individual trajectories still shows some signs of this dissipative freezing before it fades out for a larger symmetry breaking terms.
Comment Regarding the Functional Form of the Schmidt Law
Creators: name: Williams, Peter Todd
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Star formation rates on the galactic scale are described phenomenologically by two distinct relationships, as emphasized recently by Elmegreen (2002). The first of these is the Schmidt law, which is a power-law relation between the star formation rate and the column density. The other relationship is that there is a cutoff in the gas density below which star formation shuts off. The purpose of this paper is to argue that 1) these two relationships can be accommodated by a single functional form of the Schmidt law, and 2) this functional form is motivated by the hypothesis that star formation is a critical phenomenon, and that as a corollary, 3) the existence of a sharp cutoff may thus be an emergent property of galaxies, as was argued by Seiden (1983), as opposed to the classical view that this cutoff is due to an instability criterion.
description: 14 pages, 3 figures, in press, New Astronomy. Figs provided in original (png) format as well as ps format for ps/pdf generation
Higher Degree Davenport Constants over Finite Commutative Rings
Creators: name: Caro, Yair
name: Girard, Benjamin
name: Schmitt, John R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: Commutative Algebra (math.AC)
subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 05E40 (Primary), 11B30, 13M10 (Secondary)

description: We generalize the notion of Davenport constants to a `higher degree' and obtain various lower and upper bounds, which are sometimes exact as is the case for certain finite commutative rings of prime power cardinality. Two simple examples that capture the essence of these higher degree Davenport constants are the following. 1) Suppose $n = 2^k$, then every sequence of integers $S$ of length $2n$ contains a subsequence $S'$ of length at least two such that $\sum_{a_i,a_j \in S'} a_ia_j \equiv 0 \pmod{n}$ and the bound is sharp. 2) Suppose $n \equiv1 \pmod{2}$, then every sequence of integers $S$ of length $2n -1$ contains a subsequence $S'$ of length at least two such that $\sum_{a_i,a_j \in S'} a_ia_j \equiv 0 \pmod{n}$. These examples illustrate that if a sequence of elements from a finite commutative ring is long enough, certain symmetric expressions have to vanish on the elements of a subsequence.
description: 16 pages
Colloidal particles at a nematic-isotropic interface: effects of confinement
Creators: name: West, J. L.
name: Zhang, K.
name: Glushchenko, A.
name: Andrienko, D.
name: Tasinkevych, M.
name: Reznikov, Y.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: When captured by a flat nematic-isotropic interface, colloidal particles can be dragged by it. As a result spatially periodic structures may appear, with the period depending on a particle mass, size, and interface velocity~\cite{west.jl:2002}. If liquid crystal is sandwiched between two substrates, the interface takes a wedge-like shape, accommodating the interface-substrate contact angle and minimizing the director distortions on its nematic side. Correspondingly, particles move along complex trajectories: they are first captured by the interface and then `glide' towards its vertex point. Our experiments quantify this scenario, and numerical minimization of the Landau-de Gennes free energy allow for a qualitative description of the interfacial structure and the drag force.
description: 7 pages, 9 figures
An accreting millisecond pulsar with black hole-like X-ray variability: IGR J00291+5934
Creators: name: Linares, Manuel
name: van der Klis, Michiel
name: Wijnands, Rudy
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: IGR J00291+5934 is one of the seven accreting millisecond pulsars (AMPs) discovered so far. We report on the aperiodic timing and color analysis of its X-ray flux, using all the RXTE observations of the 2004 outburst. Flat-top noise and two harmonically related quasi-periodic oscillations, all of them at very low frequencies (0.01-0.1 Hz), were present in the power spectra during most of the outburst as well as a very high fractional variability (~50%). These properties are atypical not only for AMPs but also for neutron star low-mass X-ray binaries (LMXBs) in general. There are instead some remarkable similarities with the variability observed in black hole systems, reinforcing the connections between these two types of LMXB, as well as some interesting differences. We note finally that the results of this paper are difficult to reconcile with interpretations where any break frequency of power density spectra scales inversely with the mass of the central object at an accuracy sufficient to distinguish between the masses of neutron stars and black holes in LMXBs.
description: Accepted by The Astrophysical Journal. Scheduled for ApJ May 1, 2007, v660n1 issue. Minor changes according to referee's comments
The Minimal Flavor Structure from Decomposition of the Fermion Mass Matrix
Creators: name: Zhang, Ying
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The minimal flavor structures for both quarks and leptons are proposed to address fermion mass hierarchy and flavor mixings by bi-unitary decomposition of the fermion mass matrix. The real matrix ${\bf M}_0^f$ is completely responsive to family mass hierarchy, which is expressed by a close-to-flat matrix structure. The left-handed unitary phase ${\bf F}_L^f$ provides the origin of CP violation in quark and lepton mixings, which can be explained as a quantum effect between Yukawa interaction states and weak gauge states. The minimal flavor structure is realized by just 10 parameters without any redundancy, corresponding to 6 fermion masses, 3 mixing angles and 1 CP violation in the quark/lepton sector. This approach provides a general flavor structure independent of the specific quark or lepton flavor data. We verify the validation of the flavor structure by reproducing quark/lepton masses and mixings. Some possible scenarios that yield the flavor structure are also discussed.
description: 15 pages, 5 figures, 2 tables, includes appendix
Critical fermi surfaces and non-fermi liquid metals
Creators: name: Senthil, T.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: At certain quantum critical points in metals an entire Fermi surface may disappear. A crucial question is the nature of the electronic excitations at the critical point. Here we provide arguments showing that at such quantum critical points the Fermi surface remains sharply defined even though the Landau quasiparticle is absent. The presence of such a critical Fermi surface has a number of consequences for the universal phenomena near the quantum critical point which are discussed. In particular the structure of scaling of the universal critical singularities can be significantly modified from more familiar criticality. Scaling hypotheses appropriate to a critical fermi surface are proposed. Implications for experiments on heavy fermion critical points are discussed. Various phenomena in the normal state of the cuprates are also examined from this perspective. We suggest that a phase transition that involves a dramatic reconstruction of the Fermi surface might underlie a number of strange observations in the metallic states above the superconducting dome.
description: 15 pages, 7 figures; some clarificatory remarks/references added and typos fixed
Confirmation of a Brown Dwarf Binary Candidate
Creators: name: Adorno, Jose I.
name: Vos, Johanna
Publisher: name: Zenodo
Year: 2021
Subjects: Brown Dwarf

description: The statistical properties of populations of brown dwarf binaries have profound implications on the basic physics of star formation and solar system assembly. Additionally, binary systems present a unique opportunity to determine dynamical masses, which are essential for testing evolutionary model predictions. We present a sample of 9 unresolved L-dwarfs imaged at high resolution with the NACO (Nasmyth Adaptive Optics System [NAOS] Near-Infrared Imager and Spectrograph [CONICA]) instrument at the VLT (Very Large Telescope). We confidently confirm 1 low-mass binary system. This new binary is a great point of study for further investigation and insight into brown dwarf binary systems.
Remarks on the stack of coherent algebras
Creators: name: Lieblich, Max
Publisher: name: arXiv
Year: 2006
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14D20

description: We consider the stack of coherent algebras with proper support, a moduli problem generalizing Alexeev and Knutson's stack of branchvarieties to the case of an Artin stack. The main results are proofs of the existence of Quot and Hom spaces in greater generality than is currently known and several applications to Alexeev and Knutson's original construction: a proof that the stack of branchvarieties is always algebraic, that limits of one-dimensional families always exist, and that the connected components of the stack of branchvarieties are proper over the base under certain hypotheses on the ambient stack.
description: 9 pages; several sections and new results added; to appear in IMRN
Generalizations of Alladi's formula for arithmetical semigroups
Creators: name: Duan, Lian
name: Ma, Ning
name: Yi, Shaoyun
Publisher: name: arXiv
Year: 2021
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: Primary 11N80, 11R45, 20M13, Secondary 11G25, 11M41, 11R44, 11R58

description: In this article, we prove that a general version of Alladi's formula with Dirichlet convolution holds for arithmetical semigroups satisfying Axiom $A$ or Axiom $A^{\#}$. As applications, we apply our main results to certain semigroups coming from algebraic number theory, arithmetical geometry and graph theory, particularly generalizing the results of Wang 2021, Kural et al. 2020 and Duan et al. 2020.
description: Some minor changes. Published online in The Ramanujan Journal
Effects of a Supermassive Black Hole Binary on a Nuclear Gas Disk
Creators: name: Matsui, Hidenori
name: Habe, Asao
name: Saitoh, Takayuki R.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study influence of a galactic central supermassive black hole (SMBH) binary on gas dynamics and star formation activity in a nuclear gas disk by making three-dimensional Tree+SPH simulations. Due to orbital motions of SMBHs, there are various resonances between gas motion and the SMBH binary motion. We have shown that these resonances create some characteristic structures of gas in the nuclear gas disk, for examples, gas elongated or filament structures, formation of gaseous spiral arms, and small gas disks around SMBHs. In these gaseous dense regions, active star formations are induced. As the result, many star burst regions are formed in the nuclear region.
description: 19 pages, 11 figures, accepted for publication in ApJ
Next Generation Models for Portfolio Risk Management: An Approach Using Financial Big Data
Creators: name: Jung, Kwangmin
name: Kim, Donggyu
name: Yu, Seunghyeon
Publisher: name: arXiv
Year: 2021
Subjects: subject: Risk Management (q-fin.RM)
subject: Econometrics (econ.EM)
subject: Portfolio Management (q-fin.PM)
subject: FOS: Economics and business

description: This paper proposes a dynamic process of portfolio risk measurement to address potential information loss. The proposed model takes advantage of financial big data to incorporate out-of-target-portfolio information that may be missed when one considers the Value at Risk (VaR) measures only from certain assets of the portfolio. We investigate how the curse of dimensionality can be overcome in the use of financial big data and discuss where and when benefits occur from a large number of assets. In this regard, the proposed approach is the first to suggest the use of financial big data to improve the accuracy of risk analysis. We compare the proposed model with benchmark approaches and empirically show that the use of financial big data improves small portfolio risk analysis. Our findings are useful for portfolio managers and financial regulators, who may seek for an innovation to improve the accuracy of portfolio risk estimation.
description: 59 pages, 6 figures
Couplings of hybrid operators to ground and excited states of bottomonia
Creators: name: Burch, Tommy
name: Ehmann, Christian
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We analyze the overlap of local color-octet meson operators with the $Υ$ and the $η_b$ and their low-lying excited states, especially the first radial excitations. Our analysis is based on NRQCD and includes all terms up to order $v^4$. We use a variety of source and sink operators as a basis for the variational method, which enables us to clearly separate the mass eigenstates and hence to extract the desired amplitudes. The results show the usefulness of the variational method for determining couplings to excited hadronic states.
description: 24 pages, 15 figures, references added, typos fixed, further analysis added
Ανάλυση γραπτών κειμένων αλλοδαπών μαθητών της υποχρεωτικής εκπαίδευσης:
Creators: name: Κυριαζή, Ειρήνη Αθανασίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Γλωσσικά λάθη
Αλλοδαποί μαθητές
Δεύτερη γλώσσα
Language errors
Foreign students
Second language

description: Η παρούσα εργασία έχει ως σκοπό να ανιχνεύσει τη φύση και τον αριθμό των λαθών αλλοδαπών μαθητών που φοιτούν σε ελληνικά σχολεία μέσω της εξέτασης γραπτών κειμένων. Γλώσσα, διγλωσσία, εκμάθηση γλώσσας και λάθη αποτελούν έννοιες στενά συνδεδεμένες, οι οποίες αξίζουν να εξεταστούν και να αποτελέσουν το υπόβαθρο της εργασίας μας. Το λάθος μπορεί να θεωρηθεί «εύπορο πεδίο» προς ερευνητική μελέτη, ικανό να μας παρέχει πληροφορίες για την εξελικτική διαδικασία εκμάθησης μιας γλώσσας, τον τρόπο επεξεργασίας των γλωσσικών ερεθισμάτων, τις δυσκολίες που αντιμετωπίζουν οι μαθητές, με απώτερο σκοπό την προσαρμογή διδασκαλίας και παιδαγωγικών εργαλείων στις ανάγκες ενός πολύγλωσσου μαθητικού κοινού. Λαμβάνοντας υπόψη ότι η στατική συνάντηση μαθητή – εκπαιδευτικού – λάθους δημιουργεί συναισθήματα άγχους και ανασφάλειας σε μαθητή και εκπαιδευτικό, ενώ η δυναμική του αξιοποίηση εκπαιδεύει τους μαθητές να σκέφτονται με συστηματικό τρόπο χρησιμοποιώντας κεκτημένες γνώσεις, θεωρούμε ότι η εξέταση των γλωσσικών λαθών αποτελεί θέμα με ιδιαίτερο παιδαγωγικό ενδιαφέρον. Στο πρώτο μέρος της εργασίας μας παρουσιάζεται το θεωρητικό πλαίσιο ενώ στο δεύτερο παραθέτουμε τα ευρήματα της έρευνας.
description: The present work has as an objective to identify the most common types of the language errors made by foreign language learners. Language, language acquisition and language errors are closely linked and deserve to be studied. The subject of language errors is a privileged area able to provide information about the process of language acquisition and the difficulties that influence learning. Therefore, it is very important to examine the factors that students who come from a culturally different environment face in order to help them overcome any problems they may encounter in the learning process. A static encounter contact between student – teacher – mistake can engender insecurity but a dynamic encounter can lead to knowledge exploitation. In the plan of our memoire, the first part is dedicated to our theoretical framework, whilst the second part, to the methods and techniques used as well as the analysis of our findings.
Square lattice site percolation thresholds for complex neighbourhoods
Creators: name: Majewski, M.
name: Malarz, K.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: In this paper we compute the square lattice random sites percolation thresholds in case when sites from the 4th and the 5th coordination shells are included for neighbourhood. The obtained results support earlier claims, that (a) the coordination number and the space dimension are insufficient for building universal formulae for percolation thresholds and (b) that percolation threshold may not decrease monotonically with lattice site coordination number.
description: RevTeX4, 5 pages, 4 figures in 28 eps files
Real-time motion tracking: a case study in parallelizing vision algorithms
Creators: name: Bulmer, Scott
Publisher: name: University of British Columbia
Year: 2009

description: For real-time motion tracking the computational requirements suggest a parallel processing solution be followed. This thesis describes the implementation of a parallel motion tracking system. Focus is placed on the resulting system as well as some of the factors involved when performing a conversion from an existing sequential system. Different parallelization methods are compared along with many of the other related issues involved in implementing vision systems on multiple processors. The model-based motion tracking system uses detected line segments from the image as features, and tracks these features with a least-squares solution to match the model with the correct feature configuration. A pipelined multiprocessor system was constructed which is able to achieve a high level of throughput using many features of the TMS320C40 parallel processors. The system consists of six C40 processors which communicate through ports controlled by a software router. A "handshaking" scheme is employed to coordinate data transfers between processors. The motion tracking system was able to track moving objects at the rate of about 4 frames per second.
Διερεύνηση της σημασίας του αριθμού των εξαιρεθέντων λεμφαδένων σε ασθενείς με καρκίνο του παχέος εντέρου: μία μελέτη επιβίωσης:
Creators: name: Ντινόπουλος, Βασίλειος Απόστολου
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Καρκίνος παχέος εντέρου
Αριθμός λεμφαδένων
Επιβίωση
Colorectal cancer
Number of lymph nodes
Survival

description: Η ύπαρξη συσχέτισης μεταξύ αριθμού εξαιρεθέντων λεμφαδένων και επιβίωσης ασθενών με καρκίνο του παχέος εντέρου σταδίου Ι, ΙΙ και ΙΙΙ αποτελεί αντικείμενο έντονης αντιπαράθεσης στην ιατρική κοινότητα. Σκοπός της μελέτης είναι η αποσαφήνιση της ύπαρξης συσχέτισης μεταξύ τους, σταθμίζοντας για συγχυτικούς παράγοντες που επηρεάζουν την επιβίωση. Πραγματοποιήθηκε μελέτη επιβίωσης 313 ασθενών που χειρουργήθηκαν στο Α.Ν.Θ. Θεαγένειο την περίοδο 2000-2008. Για την ανάλυση των δεδομένων χρησιμοποιήθηκε το μοντέλο αναλογικών κινδύνων του Cox στο οποίο διερευνήθηκε μονοπαραγοντικά και πολυπαραγοντικά η σχέση μεταξύ επιβίωσης και ηλικίας, φύλου, συννοσηρότητας, Τ σταδίου, αριθμού διηθημένων λεμφαδένων, αριθμού εξαιρεθέντων λεμφαδένων, ιστολογικού τύπου, βαθμού διαφοροποίησης, διήθησης λεμφικών ή αιμοφόρων αγγείων, περινευρικής διήθησης και εξωλεμφαδενικών καρκινικών εναποθέσεων. Από τη μονοπαραγοντική ανάλυση παρατηρήθηκε στατιστικά σημαντική συσχέτιση της επιβίωσης με την ηλικία (p<0,001), τη συννοσηρότητα (p=0,035), τον αριθμό διηθημένων λεμφαδένων (p<0,001) και τη διήθηση λεμφικών ή αιμοφόρων αγγείων (p=0,005). Από την πολυπαραγοντική ανάλυση παρατηρήθηκε στατιστικά σημαντική συσχέτιση της επιβίωσης με την ηλικία (HR=1,073, 95% CI: 1,039-1,108, p<0,001) και τον αριθμό διηθημένων λεμφαδένων (HR=1,146, 95% CI: 1,092-1,203, p<0,001). Δεν παρατηρήθηκε στατιστικά σημαντική συσχέτιση μεταξύ αριθμού εξαιρεθέντων λεμφαδένων και επιβίωσης στους ασθενείς της μελέτης, επομένως εκτεταμένοι λεμφαδενικοί καθαρισμοί δε φαίνεται να βελτιώνουν την επιβίωση των ασθενών με καρκίνο του παχέος εντέρου σταδίου Ι, ΙΙ και ΙΙΙ.
description: Association between lymph node yield and survival in patients with stage I, II and III colorectal cancer remains disputed among medical practitioners. Aim of this study was to assess whether such correlation exists, weighting for confounding factors. A survival analysis was conducted, which included 313 patients operated at Theageneio Cancer Hospital of Thessaloniki during 2000-2008. Data analysis was performed using the Cox proportional hazards model. Univariate and multivariate analysis was performed for assessment of association between survival and age, sex, comorbidity, T stage, number of infiltrated lymph nodes, number of harvested lymph nodes, histological type, differentiation grade, lymphovascular invasion, perineural invasion and extranodal tumor deposits. Univariate analysis showed statistically significant association between survival and age (p
U-boson at BESIII
Creators: name: Zhu, Shou-hua
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The $O$(MeV) spin-1 U-boson has been proposed to mediate the interaction among electron-positron and $O$(MeV) dark matter, in order to account for the 511 keV $γ$-ray observation by SPI/INTEGRAL. In this paper the observability of such kind of U-boson at BESIII is investigated through the processes $e^+e^- \to U γ$ and $e^+e^- \to J/Ψ\to e^+e^- U$. We find that BESIII and high luminosity B-factories have the comparable capacity to detect such U-boson. If U-boson decays mainly into dark matter, i.e. invisibly, BESIII can measure the coupling among U-boson and electron-positron $g_{eR}$ (see text) down to $O(10^{-5})$, and cover large parameter space which can account for 511 keV $γ$-ray observation. On the other hand, provided that U decays mainly into electron-positron, BESIII can detect $g_{eR}$ down to $O(10^{-3})$, and it is hard to explore 511 keV $γ$-ray measurement allowed parameter space due to the irreducible QED backgrounds.
description: 3 refs added, minor text modification, PRD version
Self-consistent Ornstein-Zernike approximation for molecules with soft cores
Creators: name: Hoye, J. S.
name: Reiner, A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The Self-Consistent Ornstein-Zernike Approximation (SCOZA) is an accurate liquid state theory. So far it has been tied to interactions composed of hard core repulsion and long-range attraction, whereas real molecules have soft core repulsion at short distances. In the present work, this is taken into account through the introduction of an effective hard core with a diameter that depends upon temperature only. It is found that the contribution to the configurational internal energy due to the repulsive reference fluid is of prime importance and must be included in the thermodynamic self-consistency requirement on which SCOZA is based. An approximate but accurate evaluation of this contribution relies on the virial theorem to gauge the amplitude of the pair distribution function close to the molecular surface. Finally, the SCOZA equation is transformed by which the problem is reformulated in terms of the usual SCOZA with fixed hard core reference system and temperature-dependent interaction.
Low frequency ac transmission for power systems
Creators: name: Ngo, Tuan Anh, 1985-
Publisher: name: The University of Texas at Austin
Year: 2017
Subjects: Low frequency ac (LFAC) transmission
LFAC voltage stability
LFAC protection

description: Conventional transmission systems utilize either high voltage ac (HVAC), operating at 50 or 60 Hz, or high voltage dc (HVDC) to transfer bulk power. The HVAC system is designed to operate at a high voltage level to reduce losses and increase bulk power transfer. This method is limited, however, by the constraints of installed transmission overhead lines, such as voltage level and power transfer capability. In contrast, the HVDC system can handle a large amount of power on the transmission line by utilizing dc current instead of ac. While the HVDC system has no limitation in transmission line length for power transfer, it does however, require a high initial cost for converter stations and specialized protection systems. Additionally, the HVDC system is a point-to-point connection, and thus not flexible for multi-terminal connection. The low frequency ac (LFAC) transmission system, first introduced in 2000, is another solution for bulk power transmission that inherits advantages from both high voltage ac and high voltage dc systems. The primary advantage of LFAC transmission is that by operating the system at a frequency lower than 50 or 60 Hz, the transmission line reactance can be significantly reduced, thus extending power capacity. Further advantages include multi-terminal connections, distance protection using alternating-current based circuit breakers, and improving power transfer capability close to that of an HVDC system. This dissertation investigates the benefits of an LFAC system in terms of power transfer capability and voltage stability. First, the steady-state performances of the transmission line under low frequency range are investigated, including the skin effect to see any possible changes in transmission line model. More importantly, the power transfer capability, and voltage profiles during no-load and full-load conditions are examined. Next, the system voltage stability under low frequency operations is studied in detail to analyze how the low frequency operation helps improve a power system stability. Furthermore, the system modeling, protection, and hardware platform to test the low frequency ac transmission are studied deeply. A new grid synchronization configuration to interface a low frequency system with a 60 Hz ac system is also proposed. Moreover, a fast and robust fault detection mechanism based on the second-order generalized-integrator (SOGI) grid synchronization technique is to develop and work properly in a low frequency system. Last but not least, a small-scaled transmission and distribution system is built to verify the basic performances of a power system at a low frequency operations.
Large-Scale Meta-Learning with Continual Trajectory Shifting
Creators: name: Shin, Jaewoong
name: Lee, Hae Beom
name: Gong, Boqing
name: Hwang, Sung Ju
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Meta-learning of shared initialization parameters has shown to be highly effective in solving few-shot learning tasks. However, extending the framework to many-shot scenarios, which may further enhance its practicality, has been relatively overlooked due to the technical difficulties of meta-learning over long chains of inner-gradient steps. In this paper, we first show that allowing the meta-learners to take a larger number of inner gradient steps better captures the structure of heterogeneous and large-scale task distributions, thus results in obtaining better initialization points. Further, in order to increase the frequency of meta-updates even with the excessively long inner-optimization trajectories, we propose to estimate the required shift of the task-specific parameters with respect to the change of the initialization parameters. By doing so, we can arbitrarily increase the frequency of meta-updates and thus greatly improve the meta-level convergence as well as the quality of the learned initializations. We validate our method on a heterogeneous set of large-scale tasks and show that the algorithm largely outperforms the previous first-order meta-learning methods in terms of both generalization performance and convergence, as well as multi-task learning and fine-tuning baselines.
Τεχνικογεωλογικές συνθήκες του φράγματος του Ιάσμου, Ν. Ροδόπης:
Creators: name: Τσιφή, Παυλίνα-Δέσποινα Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Φράγμα
Τεχνικογεωλογικές συνθήκες
Ίασμος
Dam
Geotechnical conditions
Iasmos

description: Στην παρούσα έρευνα παρουσιάζεται η γεωλογική και τεχνικογεωλογική αξιολόγηση πρωτογενών δεδομένων για την κατασκευή του φράγματος Ιάσμου, Ν. Ροδόπης. Τα δεδομένα που επεξεργάστηκαν στην εργασία, αφορούν βιβλιογραφικά στοιχεία της γεωλογίας της περιοχής, τεχνικογεωλογικά στοιχεία των ερευνητικών γεωτρήσεων, στοιχεία αποσάθρωσης, μετρήσεις τεκτονικών στοιχείων, μετρήσεις επιτόπου και εργαστηριακών δοκιμών, όπως μονοαξονικών και τριαξονικών δοκιμών και δοκιμών σημειακής φόρτισης. Από εργασία στην ύπαιθρο με αξιολόγηση και επεξεργασία των στοιχείων, πραγματοποιήθηκαν ταξινομήσεις κατά G.S.I. και R.M.R. για τους διάφορους τύπους βραχόμαζας. Επίσης, εκτιμήθηκε, η στεγανότητα στον άξονα έδρασης του φράγματος από τις επί τόπου δοκιμές περατότητας (κυρίως Lugeon), και κατά συνέπεια η έκταση και το βάθος της κουρτίνας τσιμεντενέσεων. Τέλος, πραγματοποιήθηκαν γεωτεχνικές αναλύσεις, όπου προσομοιώνονται τα τεχνικογεωλογικά χαρακτηριστικά σε ειδικό λογισμικό, με στόχο τον έλεγχο των παραμορφώσεων στη περιοχή, την θεμελίωση του φράγματος και την εκτίμηση των υδατικών πιέσεων κάτω από το φράγμα.
description: In the present investigation is presented the geological and geotechnical evaluation of primary data of the dam Iasmos, Rodopi area in Northern Greece. The data processed concerns desk study, geotechnical investigation from the drillings, such us geotechnical classification by G.S.I. and R.Q.D., weathering grades, in situ and laboratory tests, such us uniaxial and triaxial tests and point load tests. It was also evaluated the tightness along the axis of the dam from the in situ permeability tests (mainly Lugeon tests), and consequently the extent and the depth of the grout curtain. Last, geotechnical analyzes in special software were performed in order to simulate the geotechnical characteristics, and evaluate the deformations below the foundation of the dam and estimate the groundwater leakage under the dam.