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Results for "N. Lessmann"

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Automatic brain tissue segmentation in fetal MRI using convolutional neural networksJun 11 2019MR images of fetuses allow clinicians to detect brain abnormalities in an early stage of development. The cornerstone of volumetric and morphologic analysis in fetal MRI is segmentation of the fetal brain into different tissue classes. Manual segmentation ... More
Simple Homogeneous ModelsJan 04 2001Jul 25 2002Geometrical stability theory is a powerful set of model-theoretic tools that can lead to structural results on models of a simple first-order theory. Typical results offer a characterization of the groups definable in a model of the theory. The work is ... More
Abstract decomposition theorem and applicationsSep 29 2005Let K be an Abstract Elementary Class. Under the asusmptions that K has a nicely behaved forking-like notion, regular types and existence of some prime models we establish a decomposition theorem for such classes. The decomposition implies a main gap ... More
Iterative fully convolutional neural networks for automatic vertebra segmentation and identificationApr 12 2018Feb 11 2019Precise segmentation and anatomical identification of the vertebrae provides the basis for automatic analysis of the spine, such as detection of vertebral compression fractures or other abnormalities. Most dedicated spine CT and MR scans as well as scans ... More
Direct and Real-Time Cardiovascular Risk PredictionDec 08 2017Coronary artery calcium (CAC) burden quantified in low-dose chest CT is a predictor of cardiovascular events. We propose an automatic method for CAC quantification, circumventing intermediate segmentation of CAC. The method determines a bounding box around ... More
Automatic calcium scoring in low-dose chest CT using deep neural networks with dilated convolutionsNov 01 2017Feb 01 2018Heavy smokers undergoing screening with low-dose chest CT are affected by cardiovascular disease as much as by lung cancer. Low-dose chest CT scans acquired in screening enable quantification of atherosclerotic calcifications and thus enable identification ... More
Direct Automatic Coronary Calcium Scoring in Cardiac and Chest CTFeb 12 2019Cardiovascular disease (CVD) is the global leading cause of death. A strong risk factor for CVD events is the amount of coronary artery calcium (CAC). To meet demands of the increasing interest in quantification of CAC, i.e. coronary calcium scoring, ... More
Interpreting groups and fields in some nonelementary classesJun 23 2004This paper is concerned with extensions of geometric stability theory to some nonelementary classes. We prove the following theorem: Theorem: Let C be a large homogeneous model of a stable diagram D. Let p, q in S_D(A), where p is quasiminimal and q unbounded. ... More
Evaluating software defect prediction performance: an updated benchmarking studyJan 07 2019Accurately predicting faulty software units helps practitioners target faulty units and prioritize their efforts to maintain software quality. Prior studies use machine-learning models to detect faulty software code. We revisit past studies and point ... More
Direct Prediction of Cardiovascular Mortality from Low-dose Chest CT using Deep LearningOct 04 2018Cardiovascular disease (CVD) is a leading cause of death in the lung cancer screening population. Chest CT scans made in lung cancer screening are suitable for identification of participants at risk of CVD. Existing methods analyzing CT images from lung ... More
Robust identification of email tracking: A machine learning approachJun 11 2018Email tracking allows email senders to collect fine-grained behavior and location data on email recipients, who are uniquely identifiable via their email address. Such tracking invades user privacy in that email tracking techniques gather data without ... More
Can Deep Learning Predict Risky Retail Investors? A Case Study in Financial Risk Behavior ForecastingDec 14 2018Jan 17 2019The success of deep learning for unstructured data analysis is well documented but little evidence has emerged related to the structured, tabular datasets used in decision support. We address this research gap by considering the potential of deep learning ... More
SONATA: Service Programming and Orchestration for Virtualized Software NetworksMay 19 2016In conventional large-scale networks, creation and management of network services are costly and complex tasks that often consume a lot of resources, including time and manpower. Network softwarization and network function virtualization have been introduced ... More
Deep learning analysis of the myocardium in coronary CT angiography for identification of patients with functionally significant coronary artery stenosisNov 24 2017Dec 06 2017In patients with coronary artery stenoses of intermediate severity, the functional significance needs to be determined. Fractional flow reserve (FFR) measurement, performed during invasive coronary angiography (ICA), is most often used in clinical practice. ... More
Bosonic stimulation of cold 1s excitons into a harmonic potential minimum in Cu$_2$OFeb 07 2003Density distribution of cold exciton clouds generated into a strain-induced potential well by two-photon excitation in Cu$_2$O is studied at 2 K. We find that an anomalous spike, which can be interpreted as accumulation of the excitons into the ground ... More
The Universal Equation of State near the Critical Point of QCDJan 12 2004Jun 18 2004We study the universal properties of the phase diagram of QCD near the critical point using the exact renormalization group. For two-flavour QCD and zero quark masses we derive the universal equation of state in the vicinity of the tricritical point. ... More
Analytical Estimate of the Effect of Spherical Inhomogeneities on Luminosity Distance and RedshiftFeb 06 2008Jun 25 2008We provide an analytical estimate of the effect of a spherical inhomogeneity on light beams that travel through it. We model the interior of the inhomogeneity in terms of the Lemaitre-Tolman-Bondi metric. We assume that the beam source is located outside ... More
Heavy quark skyrmionsMay 18 2009The description of the heavy baryons as heavy-meson--soliton bound systems is reviewed. We outline how such bound systems arise from effective lagrangians that respect both chiral symmetry and heavy quark symmetry. Effects due to finite heavy quark masses ... More
Wind of presupernova IIn SN~1997egJan 15 2019Spectra and phototometry of type IIn supernova SN 1997eg are used to determine properties of the circumstellar gas lost by the presupernova during the latest 200 years before the explosion. The analysis of narrow H$\alpha$ and [Fe X] 6374 \AA\ results ... More
Connection between Diffraction and Small-$x$Nov 30 2001A brief review of the modern QCD theory of diffractive DIS is given.
Diffractive DIS: Where Are We?Nov 12 2001Nov 20 2001A brief review of the modern QCD theory of diffractive DIS is given. The recent progress has been remarkably rapid, all the principal predictions from the color dipole approach to diffraction - the $(Q^2+m_V^2)$ scaling, the pattern of SCHNC, shrinkage ... More
Diffractive Vector Mesons in DIS: Meson Structure and QCDSep 15 2000I review the modern status of QCD theory of diffractive vector meson production with the focus on shrinkage of photons with Q2 and (Q2+mV2)$scaling, j-plane properties of the QCD pomeron and Regge shrinkage of diffraction cone, $s$-channel helicity non-conservation ... More
Spin dependence of diffractive DISMay 31 1999I review the recent progress in the theory of s-channel helicity nonconservation (SCHNC) effects in diffractive DIS including the unitarity driven demise of the Burkhardt-Cottingham sum rule and strong scaling departure from the Wandzura-Wilczek relation. ... More
Flow-invariant hypersurfaces in semi-dispersing billiardsMar 15 2006This work results from our attempts to solve Boltzmann-Sinai's hypothesis about the ergodicity of hard ball gases. A crucial element in the studies of the dynamics of hard balls is the analysis of special hypersurfaces in the phase space consisting of ... More
New upper bound for a class of vertex Folkman numbersJan 11 2006We improve the previuosly known bound for some vertex Folkman numbers.
Upgrading the Local Ergodic Theorem for planar semi-dispersing billiardsMay 29 2007Jun 04 2009The Local Ergodic Theorem (also known as the `Fundamental Theorem') gives sufficient conditions under which a phase point has an open neighborhood that belongs (mod 0) to one ergodic component. This theorem is a key ingredient of many proofs of ergodicity ... More
Effective quantum number for axially symmetric problemsAug 15 2014We generalize the universal effective quantum number introduced earlier for centrally symmetric problems. The proposed number determines the semiclassical quantization condition for axially symmetric potentials.
Propagation of a Dark Soliton in a Disordered Bose-Einstein CondensateJun 01 2005Sep 26 2005We consider the propagation of a dark soliton in a quasi 1D Bose-Einstein condensate in presence of a random potential. This configuration involves nonlinear effects and disorder, and we argue that, contrarily to the study of stationary transmission coefficients ... More
Unnatural Oscillon Lifetimes in an Expanding BackgroundApr 19 2006Jul 11 2006We consider a classical toy model of a massive scalar field in 1+1 dimensions with a constant exponential expansion rate of space. The nonlinear theory under consideration supports approximate oscillon solutions, but they eventually decay due to their ... More
Non-linear Matter Spectrum for a Variable Equation of StateFeb 17 2010Apr 10 2014We study the growth of matter perturbations beyond the linear level in cosmologies in which the dark energy has a variable equation of state. The non-linear corrections result in shifts in the positions of the maximum, minima and nodes of the spectrum ... More
Unifying aspects of polarization of vector mesons from hard production in DIS and at TevatronAug 08 2001Virtual photons have both the transverse and longitudinal polarization. In the inclusive DIS the impact of longitudinal photons, quantified by R=sigmaL/\igmaT sim 0.2, is marginal, but in diffractive DIS with excitation of small mass hadronic states or ... More
Incomplete Tribonacci-Lucas numbers and polynomialsApr 16 2014In this paper, we define Tribonacci-Lucas polynomials and present Tribonacci-Lucas numbers and polynomials as a binomial sum. Then, we introduce incomplete Tribonacci-Lucas numbers and polynomials. In addition we derive recurrence relations, some properties ... More
Chern invariants of some flat bundles in the arithmetic Deligne cohomologyApr 09 2006In this note, we investigate the Chern classes of flat bundles in the arithmetic Deligne Cohomology, introduced by Green-Griffiths, Asakura-Saito. We show nontriviality of the Chern classes in some cases and the proof also indicates that generic flat ... More
Stability of tangent bundle on the moduli space of stable bundles on a curveNov 01 2011Feb 12 2014In this paper, we prove that the tangent bundle of the moduli space $\cSU_C(r,d)$ of stable bundles of rank $r>2$ and of fixed determinant of degree $d$ (such that $(r,d)=1$), on a smooth projective curve $C$ is always stable, in the sense of Mumford-Takemoto. ... More
Cohomological invariants of a variation of flat connectionApr 20 2015Sep 23 2015In this paper, we apply the theory of Chern-Cheeger-Simons to construct canonical invariants associated to a $r$-simplex whose points parametrize flat connections on a smooth manifold $X$. These invariants lie in degrees $(2p-r-1)$-cohomology with $C/Z$-coefficients, ... More
Random data Cauchy theory for supercritical wave equations II : A global existence resultJul 10 2007We prove that the subquartic wave equation on the three dimensional ball $\Theta$, with Dirichlet boundary conditions admits global strong solutions for a large set of random supercritical initial data in $\cap_{s<1/2} H^s(\Theta)$. We obtain this result ... More
SN 2011ht: Weak explosion in massive extended envelopeOct 21 2015Oct 29 2015A possibility is explored to account for the light curve and the low expansion velocity of the supernova SN~2011ht, a member of group of three objects showing signatures of both IIn and IIP supernovae. It is argued that the radiated energy and the expansion ... More
Affine metrics and algebroid structures: Application to general relativity and unificationAug 14 2011Affine metrics and its associated algebroid bundle are developed. Theses structures are applied to the general relativity and provide an structure for unification of gravity and electromagnetism. The final result is a field equation on the associated ... More
$ΔS = 1$ Hadronic Weak Decays of Hyperons in a Soliton ModelSep 23 1997We study the parity violating hyperon non-leptonic weak decays in the three flavor Skyrme model. We follow the approach in which the symmetry breaking terms in the action are diagonalized exactly within the collective coordinate approximation. We show ... More
Fate of k_perp-factorization for hard processes in nuclear environmentDec 15 2004Large thickness of heavy nuclei brings in a new scale into the pQCD description of hard processes in nuclear environment. The familiar linear $k_{\perp}$-factorization breaks down and must be replaced by a new concept of the nonlinear $k_{\perp}$-factorization ... More
Random data Cauchy theory for supercritical wave equations I: Local theoryJul 10 2007We study the local existence of strong solutions for the cubic nonlinear wave equation with data in $H^s(M)$, $s<1/2$, where $M$ is a three dimensional compact riemannian manifold. This problem is supercritical and can be shown to be strongly ill-posed ... More
Henon-Heiles Hamiltonian for Coupled Upper-Hybrid and Magnetoacoutic Waves in Magnetized PlasmasJul 24 1995We show that the coupled mode equations for the stationary propagation of upper--hybrid and magnetoacoustic waves in magnetized electron--ion plasmas with negative group dispersion can be exactly derived from the generalized \Henon--Heiles Hamiltonian. ... More
Circumstellar Na I and Ca II lines of type Ia supernovae in symbiotic scenarioJan 29 2008Formation of circumstellar lines of Na I and Ca II in type Ia supernovae is studied for the case, when supernova explodes in a binary system with a red giant. The model suggests a spherically-symmetric wind and takes into account ionization and heating ... More
Broad emission lines from opaque electron-scattering environment of SN 1998SJun 13 2001I propose that broad narrow-topped emission lines with full width at zero intensity >20000 km/s, seen in early-time spectra of SN 1998S, originate from a dense circumstellar gas and not from the supernova ejecta. The tremendous line width is the result ... More
Circumstellar interaction in type Ibn supernovae and SN 2006jcAug 05 2009I analyse peculiar properties of light curve and continua of enigmatic Ibn supernovae, including SN 2006jc, and argue in favour of the early strong circumstellar interaction. This interaction explains the high luminosity and fast flux rise of SN 1999cq, ... More
Light Scalar Mesons as Manifestation of Spontaneously Broken Chiral SymmetryJan 20 2010Attention is paid to the production mechanisms of light scalars that reveal their nature. We reveal the chiral shielding of the \sigma(600) meson. We show that the kaon loop mechanism of the \phi radiative decays, ratified by experiment, points to the ... More
Strong decays of P wave baryons in the $1/N_c$ expansionApr 18 2005The hadronic decays of non-strange negative parity baryons are analyzed in the framework of the 1/Nc expansion. A complete basis of spin-flavor operators for the pseudoscalar meson S and D partial wave amplitudes is established to order 1/Nc and the unknown ... More
Two and Three parametric regular generalizations of spherically symmetric and axially symmetric metricsNov 22 2002Regular generalizations of spherically and axially symmetric metrics and their properties are considered. Newton gravity law generalizations are reduced for null geodesic.
Stripes ordering in self-stratification experiments of binary and ternary granular mixturesApr 25 2000The self-stratification of binary and ternary granular mixtures has been experimentally investigated. Ternary mixtures lead to a particular ordering of the strates which was not accounted for in former explanations. Bouncing grains are found to have an ... More
Partition test and sexual motivation in male miceAug 02 2007Theoretical analysis of own and literature investigations of sexual motivation with the use of the partition test [Kudryavtseva, 1987, 1994] in male mice was carried out. It has been shown that appearance of a receptive female in the neighboring compartment ... More
Spin Dependence of Diffractive Vector Meson ProductionAug 24 1999Aug 26 1999I review the recent progress in the theory of s-channel helicity nonconservation (SCHNC) effects in diffractive DIS. SCHNC in diffractive vector meson production is an unique probe of the spin-orbit coupling and Fermi motion of quarks in vector mesons. ... More
Helicity Flip in Diffractive DISAug 26 1999I review new results on s-channel helicity nonconservation (SCHNC) in diffractive DIS. I discuss how by virtue of unitarity diffractive DIS gives rise to spin structure functions which were believed to vanish at x << 1. These include tensor polarization ... More
Asymptotic behaviour of the total cross section of p-p scattering and the Akeno cosmic ray dataApr 21 1993I present a new determination of the total cross section for proton-proton collisions from the recent Akeno results on absorption of the cosmic ray protons in the p-Air collisions. Extrapolation to the SSC energy suggests $\sigma_{tot}(p-p) \approx (160-170) ... More
Asymmetry of $^{56}$Ni ejecta and polarization in type IIP supernova 2004djAug 21 2006I study a problem, whether the asymmetry of a $^{56}$Ni ejecta that results in the asymmetry of the H$\alpha$ emission line at the nebular epoch of the type IIP supernova SN 2004dj is able also to account for the recently detected polarization of the ... More
Non-Abelian Lovelock-Born-Infeld Topological Black HolesSep 02 2009Oct 24 2009We present the asymptotically AdS solutions of the Einstein gravity with hyperbolic horizons in the presence of $So(n(n-1)/2-1, 1)$ Yang-Mills fields governed by the non-Abelian Born-Infeld lagrangian. We investigate the properties of these solutions ... More
Gaussian measures associated to the higher order conservation laws of the Benjamin-Ono equationSep 24 2011Jul 04 2012Inspired by the work of Zhidkov on the KdV equation, we perform a construction of weighted gaussian measures associated to the higher order conservation laws of the Benjamin-Ono equation. The resulting measures are supported by Sobolev spaces of increasing ... More
Stability of the Lepton-Flavor Mixing Matrix Against Quantum CorrectionsJun 24 1999Recent neutrino experiments suggest the strong evidences of tiny neutrino masses and the lepton-flavor mixing. Neutrino-oscillation solutions for the atmospheric neutrino anomaly and the solar neutrino deficit can determine the texture of neutrino mass ... More
Yukawa Interaction from a SUSY Composite ModelSep 04 1997We present a composite model that is based on non-perturbative effects of N=1 supersymmetric SU(N_C) gauge theory with N_f=N_C+1 flavors. In this model, we consider N_C=7, where all matter fields in the supersymmetric standard model, that is, quarks, ... More
Static Configurations of Dark Energy and Dark MatterSep 26 2005Dec 08 2005We study static configurations of dark matter coupled to a scalar field responsible for the dark energy of the Universe. The dark matter is modelled as a Fermi gas within the Thomas-Fermi approximation. The mass of the dark matter particles is a function ... More
Colour transparency: a novel test of QCD in nuclear interactionsApr 20 1993Colour transparency is a cute and indispensable property of QCD as the gauge theory of strong interaction. CT tests of QCD consist of production of the perturbative small-sized hadronic state and measuring the strngth of its non-perturbative diffraction ... More
Intrinsic $k_{\perp}$ in the pomeronMay 31 1999Aug 20 1999In a consistent QCD approach to diffractive DIS gluons in the pomeron have soft $z_{g}$ distribution and very broad intrinsic $k_{\perp}$ distribution. The latter has not yet been incorporated into diffractive Monte-Carlo generators (RAPGAP,....). I argue ... More
An example of a 16-vertex Folkman edge (3,4)-graph without 8-cliquesFeb 12 2006In this paper we prove a new upper bouhd on an edge Folkman number. In a previous paper we have proved that this bound is exact.
Invariant measure for a three dimensional nonlinear wave equationJul 10 2007We study the long time behavior of the subcritical (subcubic) defocussing nonlinear wave equation on the three dimensional ball, for random data of low regularity. We prove that for a large set of radial initial data in $\cap_{s<1/2} H^s(B(0,1))$ the ... More
Modified Gauss-Newton method in low-rank signal estimationMar 04 2018The paper is devoted to the solution of a weighted non-linear least-squares problem for low-rank signal estimation, which is related Hankel structured low-rank approximation problems. The solution is constructed by a modified weighted Gauss-Newton method. ... More
Pulsar Wind Nebulae ModelingNov 27 2013Pulsar Wind Nebulae (PWNe) are ideal astrophysical laboratories where high energy relativistic phenomena can be investigated. They are close, well resolved in our observations, and the knowledge derived in their study has a strong impact in many other ... More
Neutron star crust beyond the Wigner-Seitz approximationSep 24 2007For more than three decades, the inner crust of neutron stars, formed of a solid lattice of nuclear clusters coexisting with a gas of electrons and neutrons, has been traditionally studied in the Wigner-Seitz approximation. The validity of this approximation ... More
Constraint on the internal structure of a neutron star from Vela pulsar glitchesJul 20 2016Pulsars are spinning extremely rapidly with periods as short as about $1.4$ milliseconds and delays of a few milliseconds per year at most, thus providing the most accurate clocks in the Universe. Nevertheless, sudden spin ups have been detected in some ... More
Self-interaction errors in nuclear energy density functionalsDec 21 2010When applied to a single nucleon, nuclear energy density functionals may yield a non-vanishing internal energy thus implying that the nucleon is interacting with itself. It is shown how to avoid this unphysical feature for semi-local phenomenological ... More
Propagation of H and He cosmic ray isotopes in the Galaxy: astrophysical and nuclear uncertaintiesOct 27 2012Observations of light isotopes in cosmic rays provide valuable information on their origin and propagation in the Galaxy. Using the data collected by the AMS-01 experiment in the range ~0.2-1.5 GeV/nucleon, we compare the measurements on 1H, 2H, 3He, ... More
Quasi-one-dimensional superconductors: from weak to strong magnetic fieldAug 02 1999We discuss the possible existence of a superconducting phase at high magnetic field in organic quasi-one-dimensional conductors. We consider in particular (i) the formation of a Larkin-Ovchinnikov-Fulde-Ferrell state, (ii) the role of a temperature-induced ... More
A unified description of static and dynamic properties of Fermi liquidsJan 12 1999In Landau's phenomenological Fermi-liquid theory (FLT), most physical quantities are derived from the knowledge of the energy variation $\delta E[\delta n]$ corresponding to a change $\delta n$ of the quasi-particle (QP) distribution function $n \equiv ... More
Larkin-Ovchinnikov-Fulde-Ferrell state in quasi-one-dimensional superconductorsOct 24 1994The properties of a quasi-one-dimensional (quasi-1D) superconductor with {\it an open Fermi surface} are expected to be unusual in a magnetic field. On the one hand, the quasi-1D structure of the Fermi surface strongly favors the formation of a non-uniform ... More
The system of three vortexes of two dimensional ideal hydrodinamics as a new example of the (integrable) Nambu- Poisson mechanicsMar 31 1998A Nambu-Poisson formulation of the system of three ordinary differential equations describing dynamics of three vortexes of the ideal two-dimensional hydrodynamics is given. The system is integrated by quadratures.
On quantum critical destruction of the pseudogap phaseJul 15 2016Recent data on the critical events accompanying the quenching of the pseudogap (PG) phase in hole-doped cuprates are analysed. An original multiband model with the spectrum influenced by doping has been used. Two critical dopings are expected in evolving ... More
Fermionic instantonsApr 19 2016May 03 2016We demonstrate the existence of a broad class of non-perturbative fermionic solutions to the Euclidean supergravity equations of motion, which are half-BPS and nonsingular, possess zero action, and obey an (anti)self-duality condition. These are identified ... More
Entropy and Boundary Conditions in Random Lozenge TilingsApr 06 1998The tilings of lozenges in 2 dimensions and of rhomboedra in 3 dimensions are studied when they are constrained by fixed boundary conditions. We establish a link between those conditions and free or periodic boundary ones: the entropy is written as a ... More
Twice-iterated boson-exchange scattering amplitudesJun 12 2006We calculate at two-loop order the complex-valued scattering amplitude related to the twice-iterated scalar-isovector boson-exchange between nucleons. In comparison to the once-iterated boson-exchange amplitude it shows less dependence on the scattering ... More
Spin-isospin stability of nuclear matterJan 31 2006We calculate the density-dependent spin-isospin asymmetry energy $J(k_f)$ of nuclear matter in the three-loop approximation of chiral perturbation theory. The interaction contributions to $J(k_f)$ originate from one-pion exchange, iterated one-pion exchange, ... More
Spin-asymmetry energy of nuclear matterOct 05 2004We calculate the density-dependent spin-asymmetry energy $S(k_f)$ of isospin-symmetric nuclear matter in the three-loop approximation of chiral perturbation theory. The interaction contributions to $S(k_f)$ originate from one-pion exchange, iterated one-pion ... More
Three-body spin-orbit forces from chiral two-pion exchangeDec 16 2003Using chiral perturbation theory, we calculate the density-dependent spin-orbit coupling generated by the two-pion exchange three-nucleon interaction involving virtual $\Delta$-isobar excitation. From the corresponding three-loop Hartree and Fock diagrams ... More
Isovector nuclear spin-orbit interaction from chiral pion-nucleon dynamicsJan 08 2003Using the two-loop approximation of chiral perturbation theory, we calculate the momentum and density dependent isovector nuclear spin-orbit strength $V_{ls}(p,k_f)$. This quantity is derived from the spin-dependent part of the interaction energy $\Sigma_{spin} ... More
Nuclear spin-orbit interaction from chiral pion-nucleon dynamicsJun 24 2002Using the two-loop approximation of chiral perturbation theory, we calculate the momentum and density dependent nuclear spin-orbit strength $U_{ls}(p,k_f)$. This quantity is derived from the spin-dependent part of the interaction energy $\Sigma_{spin} ... More
Chiral 2$π$-exchange NN-potentials: Relativistic $1/M^2$-CorrectionsSep 24 2001We calculate in baryon chiral perturbation theory the relativistic $1/M^2$-corrections to the leading order two-pion exchange diagrams. We give explicit expressions for the corresponding one-loop NN-amplitudes in momentum space. The resulting isovector ... More
Chiral corrections to kaon-nucleon scattering lengthsJul 03 2001Apr 21 2006We calculate the threshold T-matrices of kaon-nucleon and antikaon-nucleon scattering to one loop order in SU(3) heavy baryon chiral perturbation theory. To that order the complex-valued isospin-1 $\bar KN$ threshold T-matrix can be successfully predicted ... More
$pp\to ppω$ reaction near thresholdJul 29 1999We analyze the total cross section data for $pp \to pp\omega$ near threshold measured recently at SATURNE. Using an effective range approximation for the on-shell $pp$ S-wave final state interaction we extract from these data the modulus $|\Omega| = 0.53$ ... More
Two more years of GRB optical afterglowsJan 31 2003Feb 04 2003I review the main observational achievements concerning GRB optical afterglows occurred in the past two years. Their emission seems to be well interpreted in terms of the `fireball' model, although a variety of behaviours are observed. Evidence for supernova-like ... More
Swift observation of Segue 1: constraints on sterile neutrino parameters in the darkest galaxyOct 22 2010Oct 25 2010Some extensions of standard particle physics postulate that dark matter may be partially composed of weakly interacting sterile neutrino particles that have so far eluded detection. We use a short (~5 ks) archival X-ray observation of Segue 1 obtained ... More
Pareidolic Dark Matter (PaDaM)Mar 28 2013A pareidolic conjecture for the Fermi Large Area Telescope.
An Uncertainty Relation of Space-TimeMar 17 1999Jun 15 1999We propose an uncertainty relation of space-time. This relation is characterized by GhT \lesssim \delta V, where T and \delta V denote a characteristic time scale and a spatial volume, respectively. Using this uncertainty relation, we give qualitative ... More
Jet quenchingOct 12 2004Jet quenching studies play a prominent role in our current understanding of ultra-relativistic heavy ion collisions. In this review I first present the available formalism to compute medium-induced gluon radiation. Then I discuss its effect on single ... More
Nuclear effects in QCDMar 31 1998Apr 01 1998Production of Drell-Yan pairs and open and hidden heavy flavor on nuclear targets is examined within perturbative QCD. The effects of modifications of nucleon structure functions inside the nuclear medium are considered. Besides, nuclear dependence of ... More
Calculus teaching and learning in South KoreaApr 29 2015This article discusses an experience of teaching Calculus classes for the freshmen students enrolled at Sungkyunkwan University, one of the private universities in South Korea. The teaching and learning approach is a balance combination between the teacher-oriented ... More
Supersymmetric Unified ModelsMay 31 1996Jun 14 1996Supersymmetry and Supersymmetric models are reviewed. Lecture given at the KOSEF-JSPS Winter School, Recent Developments in Particle and Nuclear Theory February 21- March 2, 1996,
Produits dans la cohomologie des variétés arithmétiques : quelques calculs sur les séries thêtaDec 15 2006For abelian varieties $A$, in the most interesting cohomology theories $H^* (A)$ is the exterior algebra of $H^1(A)$. In this paper we study a weak generalization of this in the case of arithmetic manifolds associated to orthogonal or unitary groups. ... More
Représentations cohomologiques isolées, applications cohomologiquesNov 28 2005We give a new proof of a Theorem of Vogan which classify the cohomological representations of a real semisimple Lie group $G$ which are isolated in the unitary dual of $G$. We investigate the same question in the automorphic dual, and obtain partial results. ... More
On fractionality of the path packing problemSep 21 2008Nov 23 2008In this paper, we study fractional multiflows in undirected graphs. A fractional multiflow in a graph G with a node subset T, called terminals, is a collection of weighted paths with ends in T such that the total weights of paths traversing each edge ... More
Quantum nonlocality: How does Nature perform the trick?\cite{Bellprize}Dec 08 2009Since our early childhood we know in our bones that in order to interact with an object we have either to go to it or to throw something at it. Yet, contrary to all our daily experience, Nature is nonlocal: there are spatially separated systems that exhibit ... More
Magnet stability and reproducibilityMar 08 2011Magnet stability and reproducibility have become increasingly important as greater precision and beams with smaller dimension are required for research, medical and other purpose. The observed causes of mechanical and electrical instability are introduced ... More
Numerical treatment of long-range Coulomb potential with Berggren basesNov 09 2010May 05 2011The Schrodinger equation incorporating the long-range Coulomb potential takes the form of a Fredholm equation whose kernel is singular on its diagonal when represented by a basis bearing a continuum of states, such as in a Fourier-Bessel transform. Several ... More
Precise Coulomb wave functions for a wide range of complex l, eta and zFeb 06 2007A new algorithm to calculate Coulomb wave functions with all of its arguments complex is proposed. For that purpose, standard methods such as continued fractions and power/asymptotic series are combined with direct integrations of the Schrodinger equation ... More