bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulmonary edema of enterovirus 71 encephalomyelitis is associated with left ventricular failure: Implications for treatment
Authors: Fu Yun‐Ching , Chi Ching‐Shiang , Jan Sheng‐Ling , Wang Teh‐Ming , Chen Po‐Yen , Chang Yen , Chou Guan , Lin Chieh‐Chung , Hwang Betau , Hsu Shih‐Lan 
Published: March 2003

AbstractEpidemics of enterovirus 71 infections caused the rapid death of many children in Malaysia in 1997 and in Taiwan in 1998. Pulmonary edema occurred in most of the fatal cases and was considered to be neurogenic. The role of the heart was rarely investigated before. Between January 1998–January 2001, 34 consecutive patients who were admitted to the intensive care unit due to enterovirus infection were studied prospectively. Patients were divided into two groups: group I with pulmonary edema, and group II without pulmonary edema. Comparisons were made between the two groups based upon demographic, neurological, and cardiovascular manifestations. Group I consisted of 11 patients (5 boys, 6 girls; mean age, 22.8 months), and group II of 23 patients (12 boys, 11 girls; mean age, 28.8 months). There were no significant differences between the two groups in comparing sex, age, body weight, neurological severity, intracranial pressure, cell count, protein and glucose levels in cerebral spinal fluid, and blood pressure. All group I patients had left ventricular dysfunction, and their ejection fractions were significantly lower than those of patients in group II (37 ± 11% vs. 75 ± 6%, P < 0.001). Group I heart rates were higher than those of group II (175 ± 24 vs. 137 ± 25, P < 0.001). In group I, 9 patients who received conventional treatment died, and the only two survivors received left ventricular assist devices. In conclusion, the pulmonary edema of fulminant enterovirus 71 infection is associated with left ventricular failure. Left ventricular function is the major determinant of outcome. Early recognition of heart failure and aggressive cardiac intervention are life‐saving. Pediatr Pulmonol. 2003; 35:263–268. © 2003 Wiley‐Liss, Inc
Novel Segmented Thermoplastic Polyurethanes Elastomers Based on Tetrahydrofuran Ethylene Oxide Copolyethers as High Energetic Propellant Binders
Authors: Chen Fu‐Tai , Duo Ying‐Quan , Luo Shan‐Guo , Luo Yun‐Jun , Tan Hui‐Min 
Published: March 2003

AbstractNovel thermoplastic polyurethane (TPU) elastomers based on copolyether (tetrahydrofuran ethylene oxide) as soft segments, isophorone diisocyanate and 1,4‐butanediol as hard segments were synthesized for the purpose of using as propellant binders. In order to increase the miscibility of thermoplastic polyurethane elastomers with nitrate ester, polyethylene glycol (PEG) is incorporated in the co‐polyether (tetrahydrofuran ethylene oxide) as soft segment. When the molecular weight and content of polyethylene glycol are controlled to 4000 and 6% of soft segments, respectively, the properties of thermoplastic polyurethane elastomers are most perfect. If plasticizing ratio of nitrate ester to thermoplastic polyurethane elastomers exceeds 4 no crystallinities are determined at room temperature. The propellant samples were prepared by a conventional absorption‐rolling extrusion process and the mechanical and combustion properties evaluated afterwards. The maximum impulse reaches up to 265∼270 s which is a little bit higher than that of a HTPB propellant. The measured results reveal a promising TPE propellant candidate which shows good processing temperature (<393 K) and excellent mechanical properties. An attracting feature which can be pointed out is that the burning rate pressure exponent reaches as low as 0.36 without the addition of burning rate catalysts. This enables an easy control of propellant combustion.
Programmable quantum measurement device that approximates all projective measurements on a qubit
Authors: Fiurášek J. , Dušek M. , Filip R. 
Published: March 2003

AbstractA “universal” quantum measurement device is proposed. It can approximate any projective measurement on a qubit. The measurement basis is selected by the quantum state of a “program register''. The device is optimized with respect to maximal average fidelity. A contra‐intuitive result is that if two qubits in the same state are used as a program the average fidelity is higher than if the second program qubit is in the respective orthogonal state.
Hidden nonlocality in quantum complementarity
Authors: Filip R. 
Published: March 2003

AbstractBell's inequality violation in the which‐way experiment, demonstrating duality between visibility and distinguishability, is analyzed with taking to account the decoherence in the interferometer and which‐way detector. Consequently, boundary of local hidden variable explanation of quantum complementarity is discussed, and usefulness of the collective tests reveling hidden nonlocality is demonstrated.
Robustness of coherent control with light induced potentials
Authors: Garraway B.M. , Suominen K.‐A. 
Published: March 2003

AbstractIntense pulses of light can be used to guide a molecular system into particular molecular states even when the Franck‐Condon overlap is very small. The process of APLIP (Adiabatic Passage by Light Induced Potentials) is an example where light induced potentials effect the change of electronic state whilst maintaining the vibrational state. In this paper we look at the robustness of APLIP to some of its controlling parameters.
Antisymmetric multi‐partite quantum states and their applications
Authors: Jex I. , Alber G. , Barnett S.M. , Delgado A. 
Published: March 2003

AbstractEntanglement is a powerful resource for processing quantum information. In this context pure, maximally entangled states have received considerable attention. In the case of bipartite qubit‐systems the four orthonormal Bell‐states are of this type. One of these Bell states, the singlet Bell‐state, has the additional property of being antisymmetric with respect to particle exchange. In this contribution we discuss possible generalizations of this antisymmetric Bell‐state to cases with more than two particles and with single‐particle Hilbert spaces involving more than two dimensions. We review basic properties of these totally antisymmetric states. Among possible applications of this class of states we analyze a new quantum key sharing protocol and methods for comparing quantum states.
Quantum trajectory approach to stochastically‐induced quantum interference
Authors: Karpati A. , Adam P. , Gawlik W. , Lobodzinski B. , Janszky J. 
Published: March 2003

AbstractStochastic perturbation of two‐level atoms strongly driven by a coherent light field is analyzed by the quantum trajectory method. Narrow resonances as hole burning and dispersive Fano‐like profile occur in the spectra in the regime where the noise dominates the Rabi oscillations. It is shown that in this case the stochastic noise can unexpectedly create phase correlation between the neighboring atomic dressed states. This phase correlation is responsible for quantum interference between the related transitions resulting in anomalous modifications of the resonance fluorescence spectra.
Revealing non‐classical behaviours in the oscillatory motion of a trapped ion
Authors: Militello B. , Messina A. , Napoli A. 
Published: March 2003

AbstractThe possibility of revealing non‐classical behaviours in the dynamics of a trapped ion via measurements of the mean value of suitable operators is reported. In particular we focus on the manifestation known as “Parity Effect” which may be observed directly measuring the expectation value of an appropriate correlation operator. The experimental feasibility of our proposal is discussed.
Covariant phase observables
Authors: Pellonpää J.‐P. 
Published: March 2003

AbstractCovariant phase observables constitute a simple solution of the quantum phase problem of a single‐mode optical field. They share three important properties: their range of values is the phase interval [0,2π), they are covariant under shifts generated by the number operator (which is necessary for coherent state phase measurements), and they have the uniform phase distribution in number states. Moreover, some phase observables have been measured (e.g. the phase observable associated to the Q‐function). The canonical phase observable has some additional properties which distinguish it from other covariant phase observables: it generates number shifts, it is uniquely associated to the polar decomposition of the lowering operator (Dirac's idea [1]), it has a projection valued covariant dilation (Newton's extension [2]), and it has a projection valued discretization (the Pegg‐Barnett formalism [3]). The single‐mode covariant phase theory can easily be extended to the two‐mode theory of covariant phase difference observables. Finally, most of all phase theories have connections to the covariant phase theory.
Cavity QED with a trapped ion
Authors: Vogel W. , Di Fidio C. 
Published: March 2003

AbstractA trapped ion in a leaky cavity is studied in the regime of strong atom‐field coupling. Particular emphasis is paid on nonlinearities due to smooth localization of the ion's wavefunction and on decoherence effects caused by spontaneous emission and cavity losses. Possibilities of quantum‐state preparation are analyzed and single‐ion lasing is considered.
On the absence of large‐order divergences in superstring theory
Authors: Davis S. 
Published: March 2003

AbstractThe genus‐dependence of multi‐loop superstring amplitudes is estimated at large orders in perturbation theory using the super‐Schottky group parameterization of supermoduli space. Restriction of the integration region to a subset of supermoduli space and a single fundamental domain of the super‐modular group suggests an exponential dependence on the genus. Upper bounds for these estimates are obtained for arbitrary N‐point superstring scattering amplitudes and are shown to be consistent with exact results obtained for special type II string amplitudes for orbifold or Calabi‐Yau compactifications. The genus‐dependence is then obtained by considering the effect of the remaining contribution to the superstring amplitudes after the coefficients of the formally divergent parts of the integrals vanish as a result of a sum over spin structures. The introduction of supersymmetry therefore leads to the elimination of large‐order divergences in string perturbation theory, a result which is based only on the supersymmetric generalization of the Polyakov measure and not the gauge group of the string model.
Modelling of defects and surfaces in perovskite ferroelectrics
Authors: Borstel G. , Eglitis R. I. , Kotomin E. A. , Heifets E. 
Published: March 2003

AbstractThe results of electronic structure calculations for different terminations of SrTiO3 (100) and (110) perovskite thin films are discussed. These calculations are based on the ab initio Hartree‐Fock (HF) method and Density Functional Theory (DFT). Results are compared with previous ab initio plane‐wave LDA and classical Shell Model (SM) calculations. Calculated considerable increase of the Ti–O chemical bond covalency nearby the surface is confirmed by experimental data. Our quantum chemical calculations performed by means of the intermediate neglect of differential overlap (INDO) method confirm the existence of self‐trapped electrons in KNbO3, KTaO3 and BaTiO3 crystals. The relevant lattice relaxation energies are 0.21 eV, 0.27 eV and 0.24 eV, and the optical absorption energies 0.78 eV, 0.75 eV and 0.69 eV, respectively. We suggest a theoretical interpretation of the so‐called green luminescence (2.2–2.3 eV) in ABO3 perovskite crystals as a result of the recombination of electrons and holes forming the Charge‐Transfer‐Vibronic‐Exciton (CTVE). The calculated luminescence energies for SrTiO3, BaTiO3, KNbO3 and KTaO3 perovskite crystals are in a good agreement with the experimentally observed energies.
Orbital ordering and orbital fluctuations in transition metal oxides
Authors: Oleś Andrzej M. 
Published: March 2003

AbstractWe summarize some characteristic features of the frustrated magnetic interactions in spin‐orbital models adequate for cubic transition metal oxides with orbital degeneracy. A generic tendency towards dimerization, found already in the degenerate Hubbard model, is confirmed for t2g but not for eg systems. In the t2g case the quantum orbital fluctuations are more pronounced and contribute to a stronger competition between different magnetic and orbital states. Therefore the orbital liquid states exist in some undoped t2g systems, while in the manganites such states can be triggered only by doping.
Spinelectronics and its applications
Authors: Reiss G. , Brückl H. , Hütten A. , Schmalhorst J. , Justus M. , Thomas A. , Heitmann S. 
Published: March 2003

AbstractThe discovery of antiferromagnetic coupling in metallic Fe/Cr multilayers by Grünberg has triggered enormous research activities in the area of magnetic thin films. Additionally, the resistance of multilayers in the antiferromagnetic state is higher than in the parallel state at magnetic saturation. This Giant Magneto Resistance is caused by spin‐dependent scattering of the conduction electrons in the magnetic layers. For applications, however, moderate saturation fields, tailorable resistance characteristics and good temperature stability are required. Additional opportunities are opened by a similar effect in magnetic tunnel junctions. Here, the tunneling probability depends on the relative orientation of the magnetizations of the electrodes and thus a large dependence of the tunneling current on an external magnetic field can be found. This effect is usually called Tunneling Magneto Resistance and can again be used both for detecting external fields as well as for information storage. Much more possible applications are still ahead, especially after the finding of magnetoelectronic effects in semiconductors. In this contribution, we will sketch basic physics of these effects and give examples for current developments.
Nanocrystalline soft magnetic materials: intergrain coupling and spin freezing effects
Authors: Škorvánek I. , Kováč J. , Kötzler J. 
Published: March 2003

AbstractThe static and dynamic magnetic properties of the nanocrystalline soft magnetic FeNbB alloys consisting of Fe‐nanograins embedded in an amorphous matrix were investigated by means of dc and ac susceptibility, magnetization and hysteresis loop measurements in a wide temperature range. We show that these alloys exhibit particular complex magnetic behaviour versus temperature. The spin‐glass like behaviour at cryogenic temperatures is followed by a very soft magnetic behaviour at intermediate temperatures, and finally, a marked magnetic hardening due to decoupling between the nanograins is observed when temperature approaches the Curie temperature of the amorphous matrix. Upon further increase of temperature, the thermal relaxation of magnetization plays a dominant role. The results are discussed within a model that takes into account the presence of weakly magnetic Nb‐rich shells around the nanocrystalline grains.
Stripe fractionalization: the quantum spin nematic and the Abrikosov lattice
Authors: Zaanen J. , Nussinov Z. 
Published: March 2003

AbstractIn part (I) of this two paper series on stripe fractionalization [J. Phys. IV (France) 12, Prg‐245 (2002)], we argued that in principle the “domain wall‐ness” of the stripe phase could persist in the spin and charge disordered superconductors, and we demonstrated how this physics is in one‐to‐one correspondence with Ising gauge theory. Here we focus on yet another type of order suggested by the gauge theory: the quantum spin nematic. Although it is not easy to measure this order directly, we argue that the superconducting vortices act as perturbations destroying the gauge symmetry locally. This turns out to give rise to a simple example of a gauge‐theoretical phenomenon known as topological interaction. As a consequence, at any finite vortex density a globally ordered antiferromagnet emerges. This offers a potential explanation for recent observations in the underdoped 214 system.
Kondo effect in the presence of crystal‐field in Ce–Ni–Ge compounds
Authors: Pikul A. P. , Kaczorowski D. , Rogl P. , Grin Yu. 
Published: March 2003

AbstractPolycrystalline samples of CeNiGe3, Ce2Ni3Ge5, Ce3NiGe2, Ce3Ni2Ge7, and their nonmagnetic La or Y‐based analogues were studied by means of electrical resistivity measurements. The temperature dependencies of the electrical resistivity of YNiGe3, La2Ni3Ge5, La3NiGe2, and La3Ni2Ge7 are typical for simple intermetallics. In turn, the magnetic contributions ρmag(T) to the resistivity of the Ce‐based phases reveal in the paramagnetic region logarithmic slopes and humps, characteristic of Kondo systems with strong crystal‐field interactions, as predicted by the Cornut–Coqblin theory. The total crystal‐field splittings of the 2F5/2 ground multiplet of Ce3+ ions were estimated to be of 100–200 K. In the magnetically ordered region the resistivity strongly decreases showing at the lowest temperatures a behavior typical for electron–magnon scattering.
Correlated hopping in infinite dimensions: rigorous local approach
Authors: Shvaika A. M. 
Published: March 2003

AbstractA general approach for the description of correlated hopping in the dynamical mean‐field theory, which is based on the expansion over electron hopping around the atomic limit, is developed. It is formulated in terms of the local irreducible parts (cumulants) of Green's functions and allows to calculate thermodynamical functions. As a limiting case the Falicov–Kimball model with correlated hopping is considered.
Vertical and diagonal stripes in the extended Hubbard model
Authors: Raczkowski M. , Normand B. , Oleś A. M. 
Published: March 2003

AbstractWe extend previous real‐space Hartree–Fock studies of static stripe stability to determine the phase diagram of the Hubbard model with anisotropic nearest‐neighbor hopping t, by varying the on‐site Coulomb repulsion U and investigating locally stable structures for representative hole doping levels x = 1/8 and x = 1/6. We also report the changes in stability of these stripes in the extended Hubbard model due to next‐neighbor hopping t′ and to a nearest‐neighbor Coulomb interaction V.
Tunneling current in ferromagnetic metal – odd parity superconductor junction
Authors: Wojciechowski R. J. , Kowalewski L. , Wojtuś P. 
Published: March 2003

AbstractThe properties of tunneling conductance spectra of a ferromagnetic metal–insulator‐spin triplet superconductor junction are investigated. We take into account higher (p‐wave and f‐wave) relative angular momentum contributions to the superconducting order parameter and investigate the quasiparticle tunneling for both the unitary and non‐unitary pairing states, which are consistent with the experimental data for Sr2RuO4. The zero‐bias conductance peaks due to the quasiparticle bound states at the interface boundary and the gap‐like structure of the conductance depending on the orientation of the junction are obtained and the role of the Andreev reflection in identifying the pairing symmetry in the odd‐parity superconductors is also discussed.
Non‐ergodicity of the 1D Heisenberg model
Authors: Bak M. , Avella A. , Mancini F. 
Published: March 2003

AbstractThe relevance of zero‐energy functions, coming from zero‐energy modes and present in the structure of bosonic Green's functions, is often underestimated. Usually, their values are fixed by assuming the ergodicity of the dynamics, but it can be shown that this is not always correct. As the zero‐energy functions are connected to fundamental response properties of the system under analysis (specific heat, compressibility, susceptibility, etc.), their correct determination is not an irrelevant issue. In this paper we present some results regarding the zero‐energy functions for the Heisenberg chain of spin‐1/2 with periodic boundary conditions as functions of the number of sites, temperature, and magnetic field. Calculations are pursued for finite chains, using equations of motion, exact diagonalization and Lanczos technique, and the extrapolation to the thermodynamic limit is studied.
Effect of randomness on superconductivity and CDWin the (hard‐core) boson‐fermion model
Authors: Pawłowski G. , Robaszkiewicz S. 
Published: March 2003

AbstractWe discuss the influence of diagonal disorder (random site energy) on superconductivity (SC) and charge orderings (CDW) in a system of coexisting itinerant electrons and local pairs, described by the (hard‐core) boson‐fermion model. The evolution of the ground state properties and critical temperatures with increasing disorder is analysed. One finds that both the SC and the CDW can be substantially suppressed by the disorder effects. This is in obvious contrast with the s‐wave BCS superconductors which, according to the Anderson's theorem, are rather insensitive to the diagonal disorder (i.e. to nonmagnetic impurities).
The variational approach to the superconductivity in the Holstein–Hubbard model
Authors: Grzybowski P. , Micnas R. 
Published: March 2003

AbstractWe examine the variational squeezed‐state and the correlated squeezed‐state approach to the ground state of the Holstein–Hubbard model in the case of strong electron–phonon interaction, paying special attention to the electron–hole symmetry of the model Hamiltonian. We have found differences with respect to the results previously reported for the normal and superconducting phases, and present an improved analysis.
Monte Carlo Simulations of the 3D Ashkin–Teller Model: continuous phase transition lines
Authors: Musiał G. , Dębski L. , Kamieniarz G. 
Published: March 2003

AbstractLarge‐scale Monte Carlo simulations, based on the invariance of the Binder cumulant Q, for continuous phase transitions in the three‐dimensional Ashkin–Teller spin‐lattice model on a cubic lattice, have been performed. Using the universality hypotesis and the finite‐size‐scaling analysis, the Ising character of phase transitions from the antiferro‐ to paramagnetic phase, where the cumulant Q behavior is different than in the Ising model, is demonstrated. Some preliminary results demonstrating the existance of the tricritical points are also presented.
Specific features in magnetic resistivity of RFe11Ti single crystals
Authors: Tereshina I. S. , Nikitin S. A. , Bezkorovajnaja G. A. , Suski W. , Badurski D. 
Published: March 2003

AbstractMagnetic resistivity ρ and its anomalies in the vicinity of spin‐reorientation transitions (SRT) in single crystals of RFe11Ti (R = Y, Dy, and Er) are investigated in the temperatures range 4.2–130 K and in magnetic fields up to 8 T. Anomalous increases of magnetization σ(B) and ρ(B) are obtained for DyFe11Ti when a field of about 1–2 T is applied along the [001] axis at a temperature in the range 4.2–130 K. ErFe11Ti shows an SRT at T = 50 K from the c‐axis to a non‐collinear magnetic structure at low temperatures which also result in a sharp increase of ρ(B) at low magnetic fields.
Adiabatic sound velocity in the vicinity of phase transition in magnets
Authors: Pawlak A. 
Published: March 2003

AbstractThe Ginzburg‐Landau Hamiltonian of a magnetic system, containing magneto‐elastic as well as entropo‐elastic interactions in addition to usual magnetic ones, is considered in detail. Adiabatic longitudinal sound velocity is defined by the pressure correlation function and is found to be finite at the phase transition temperature in contrast to the behaviour of the isothermal sound velocity which goes asymptotically to zero. A weakly‐singular contribution to adiabatic sound velocity is also found. We show that it can be expressed entirely in terms of the static spin‐energy vertex function evaluated with an effective spin Hamiltonian. For the Ising‐type magnets the vertex function is found to exhibit a (T–TC)α singularity.