bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anti-Hepatitis A Virus Immunoglobulin M Antibodies in Urine Samples for Rapid Diagnosis of Outbreaks
Authors: de los Angeles Rodríguez Lay Licel , Larralde Díaz Osmany , Martínez Casanueva Raiza , Gutiérrez Moreno Aidonis 
Published: May 2003

ABSTRACT
The main goal of this study was to test the feasibility of using urine for diagnosing hepatitis A virus (HAV) infections. A correlation of 90.78% between the test results of urine and serum samples was obtained. Four outbreaks of hepatitis A were confirmed by testing only urine samples. The levels of anti-HAV immunoglobulin M (IgM) antibodies in urine samples remained stable during 6 months of storage at −70°C but decreased when the samples were stored at 4°C. The results of tests of samples obtained 2 and 6 months after infection suggested that IgM levels decline more rapidly in urine than in serum.
Activation of Coagulation by Administration of Recombinant Factor VIIa Elicits Interleukin 6 (IL-6) and IL-8 Release in Healthy Human Subjects
Authors: de Jonge Evert , Friederich Philip W. , Vlasuk George P. , Rote William E. , Vroom Margaretha B. , Levi Marcel , van der Poll Tom 
Published: May 2003

ABSTRACTThe activation of coagulation has been shown to contribute to proinflammatory responses in animal and in vitro experiments. Here we report that the activation of coagulation in healthy human subjects by the administration of recombinant factor VIIa also elicits a small but significant increase in the concentrations of interleukin 6 (IL-6) and IL-8 in plasma. This increase was absent when the subjects were pretreated with recombinant nematode anticoagulant protein c2, the inhibitor of tissue factor-factor VIIa.
MICROLOCAL SPECTRUM CONDITION AND HADAMARD FORM FOR VECTOR-VALUED QUANTUM FIELDS IN CURVED SPACETIME
Authors: SAHLMANN HANNO , VERCH RAINER 
Published: May 2003

Some years ago, Radzikowski has found a characterization of Hadamard states for scalar quantum fields on a four-dimensional globally hyperbolic spacetime in terms of a specific form of the wavefront set of their two-point functions (termed "wavefront set spectrum condition"), thereby initiating a major progress in the understanding of Hadamard states and the further development of quantum field theory in curved spacetime. In the present work, we extend this important result on the equivalence of the wavefront set spectrum condition with the Hadamard condition from scalar fields to vector fields (sections in a vector bundle) which are subject to a wave-equation and are quantized so as to fulfill the covariant canonical commutation relations, or which obey a Dirac equation and are quantized according to the covariant anti-commutation relations, in any globally hyperbolic spacetime having dimension three or higher. In proving this result, a gap which is present in the published proof for the scalar field case will be removed. Moreover we determine the short-distance saling limits of Hadamard states for vector-bundle valued fields, finding them to coincide with the corresponding flat-space, massless vacuum states.
THE INFLUENCE OF TRUCKS ON TRAFFIC FLOW — AN INVESTIGATION ON THE NAGEL–SCHRECKENBERG-MODEL
Authors: EBERSBACH ANJA , SCHNEIDER JOHANNES , MORGENSTERN INGO , HAMMWÖHNER RAINER 
Published: May 2003

A few years ago Nagel and Schreckenberg introduced a model for traffic flow,1 which, though quite simple, is able to reproduce the basic properties of traffic. Meanwhile many variations of the model have been developed, part of them concentrate on introducing an inhomogenous fleet of cars with different maximum velocities. Here we also want to study the effect of introducing a certain fraction of vehicles with a lower maximum velocity ("trucks") to the Nagel–Schreckenberg-model. We give a detailed description of this effect and focus on the time development of the influence of trucks on traffic flow.
STILL FLAT AFTER ALL THESE YEARS!
Authors: PIERPAOLI ELENA , SCOTT DOUGLAS , WHITE MARTIN 
Published: May 2003

The Universe could be spatially flat, positively curved or negatively curved. Each option has been popular at various times, partly affected by an understanding that models tend to evolve away from flatness. The curvature of the Universe is amenable to measurement, through tests such as the determination of the angles of sufficiently large triangles. The angle subtended by the characteristic scale on the cosmic microwave sky provides a direct test, which has now been realized through a combination of exquisite results from a number of CMB experiments. After a long and detailed investigation, with many false clues, it now seems that the mystery of the curvature of the Universe is now solved. It is an open and shut case: the Universe is flat!
IMPLICATIONS OF THE UNITARITY TRIANGLE "uc" FOR J, δ AND |VCKM| ELEMENTS
Authors: RANDHAWA MONIKA , BHATNAGAR V. , GILL P. S. , GUPTA M. 
Published: May 2003

The Jarlskog rephasing invariant parameter |J| is evaluated using one of the six unitarity triangles involving well-known CKM matrix elements |Vud|, |Vus|, |Vub/Vcb|, |Vcd|, |Vcs|, and |Vcb|. With PDG2000 values of |Vud| etc. as input, we obtain |J|= (2.71±1.12)×10-5, which in the PDG representation of CKM matrix leads to the range 21° to 159° for the CP violating phase δ. The CKM matrix elements evaluated using this range of δ are in agreement with the PDG CKM matrix. The implications of refinements in the input on |J|, δ and CKM matrix elements have also been studied.
COSMOLOGICAL CONSTANT OF THE INFLATING BRANES IN THE RANDALL–SUNDRUM–ODA MODEL
Authors: MERSINI LAURA 
Published: May 2003

We examine the issue of the cosmological constant in the many inflating branes scenario, extending on two recent models by I. Oda and Randall–Sundrum. The exact solution in a closed form is found in the slow-roll approximation for the branes. We show that each positive tension brane has an induced canonical cosmological constant and expansion rate that are decreasing functions of their position in the fifth dimension. The reason is that the square of the effective expansion rate enters as a source term in the Einstein equations for the branes. Thus the brane has two scale factors depending on time and the fifth dimension respectively. A displacement of the brane along the fifth dimension would adjust its effective expansion rate in such a way that it compensates for its internal energy changes due to inflation and possible phase transitions.
OSCILLATIONS OF FASTER THAN LIGHT MAJORANA NEUTRINOS: A CAUSAL FIELD THEORY
Authors: CHANG NGEE-PONG 
Published: May 2003

In this paper, we carry out the canonical quantization of the field theory of an interacting tachyonic Majorana neutrino. We show how micro-causality is preserved in the physical scattering matrix elements between the in and out vacua. The phenomenology of this radical proposal is nevertheless compatible with normal timelike oscillations.
SUBMODELS OF NONLINEAR GRASSMANN SIGMA MODELS IN ANY DIMENSION AND CONSERVED CURRENTS, EXACT SOLUTIONS
Authors: FUJII KAZUYUKI , HOMMA YASUSHI , SUZUKI TATSUO 
Published: May 2003

In the preceding paper,1 we constructed submodels of nonlinear Grassmann sigma models in any dimensions and, moreover, an infinite number of conserved currents and a wide class of exact solutions. In this letter, we first construct almost all conserved currents for the submodels and all those for CP1-model. We next review the Smirnov and Sobolev construction for the equations of CP1-submodel and extend the equations, the S-S construction and conserved currents to higher order ones.
REAL STRUCTURES IN CLIFFORD ALGEBRAS AND MAJORANA CONDITIONS IN ANY SPACE–TIME
Authors: DE ANDRADE M. A. , TOPPAN F. 
Published: May 2003

Clifford algebras and Majorana conditions are analyzed in any space–time. An index labelling inequivalent Γ-structures up to orthogonal conjugations is introduced. Inequivalent charge-operators in even dimensions, invariant under Wick rotations, are considered. The hermiticity condition on free-spinors Lagrangians is presented. The constraints put by the Majorana condition on the free-spinors dynamics are analyzed. Tables specifying which space–times admit Lagrangians with nonvanishing kinetic, massive or pseudo-massive terms (for both charge-operators in even dimensions) are given. The admissible free Lagrangians for free Majorana–Weyl spinors are fully classified.
R&D PROGRESS TOWARD FUTURE LINEAR COLLIDERS
Authors: VOSS G.-A. 
Published: May 2003

During the last 20 years there has been a worldwide effort to develop the physics and technology of linear colliders. Present goals at SLAC, KEK and DESY are to bring the R&D efforts to the point where proposals for 500/1000 GeV cms electron–positron colliders can be officially submitted in the years 2002/2003. The CLIC study at CERN aims at a second generation very high energy electron–positron collider, to be considered after completion of the LHC. The main areas of hardware R&D include efficient accelerating waveguides without harmful higher order mode (h.o.m) effects, high peak power klystrons, klystron modulators and rf-power compression. Test facilities have been put in place for the testing of h.o.m behavior of new waveguide designs (ASSET), focusing on low emittance beams to spot sizes in the nanometer range (FFTB) and damping particle oscillations in a special damping ring (ATF) to prepare low emittance bunch trains of electrons for injection into linear colliders. The TESLA collaboration is making a major effort to develop the required technology for a superconducting linear collider. Test accelerator sections, which employ all the necessary new accelerator components, have been built and are currently being tested at SLAC and DESY.
POSSIBLE INSTABILITY OF THE VACUUM IN A STRONG MAGNETIC FIELD
Authors: CALUCCI GIORGIO 
Published: May 2003

The possibility that a static magnetic field may decay through production of electron positron pairs is studied. The conclusion is that this decay cannot happen through production of single pairs, as in the electric case, but only through the production of a many-body state, since the mutual magnetic interactions of the created pairs play a relevant role. The investigation is made in view of the proposed existence of huge magnetic field strengths around some kind of neutron stars.
ASPECTS OF THE STOCHASTIC BURGERS EQUATION AND THEIR CONNECTION WITH TURBULENCE
Authors: HAYOT F. , JAYAPRAKASH C. 
Published: May 2003

We present results for the one-dimensional stochastically forced Burgers equation when the spatial range of the forcing varies. As the range of forcing moves from small scales to large scales, the system goes from a chaotic, structureless state to a structured state dominated by shocks. This transition takes place through an intermediate region where the system exhibits rich multifractal behavior. This is mainly the region of interest to us. We only mention in passing the hydrodynamic limit of forcing confined to large scales, where much work has taken place since that of Polyakov.1 In order to make the general framework clear, we give an introduction to aspects of isotropic, homogeneous turbulence, a description of Kolmogorov scaling, and, with the help of a simple model, an introduction to the language of multifractality which is used to discuss intermittency corrections to scaling. We continue with a general discussion of the Burgers equation and forcing, and some aspects of three-dimensional turbulence where — because of the mathematical analogy between equations derived from the Navier–Stokes and Burgers equations — one can gain insight from the study of the simpler stochastic Burgers equation. These aspects concern the connection of dissipation rate intermittency exponents with those characterizing the structure functions of the velocity field, and the dynamical behavior, characterized by different time constants, of velocity structure functions. We also show how the exponents characterizing the multifractal behavior of velocity structure functions in the above mentioned transition region can effectively be calculated in the case of the stochastic Burgers equation.
LOW TEMPERATURE LINEAR DYNAMICAL SUSCEPTIBILITY OF THE ISING SPIN GLASS IN A TRANSVERSE FIELD
Authors: BUSIELLO G. , SABUROVA R. V. 
Published: May 2003

Low-temperature equilibrium dynamical behavior of the linear ac susceptibility in d-dimensional Ising spin glass with short-range interactions between spins in transverse field is investigated in terms of droplet model. The real part of linear ac susceptibility [Formula: see text] as functions of temperature T and frequency of external ac field ω is calculated. Frequency and temperature dependence of [Formula: see text] shows a glassy behavior. For instance, we find a broad maximum for [Formula: see text] which shifts towards higher temperatures with increasing frequency of ac-field. The temperature of maximum Tf(ω) depends on frequency and increases with frequency up to the magnitude where [Formula: see text] starts to decrease. A qualitative agreement of our calculations with experimental data, for example, in quantum dipole magnet LiHoxY1-xF4 and proton glasses, is found.
NANO-CRYSTALS OF c-DIAMOND, n-DIAMOND AND i-CARBON GROWN IN CARBON-ION IMPLANTED FUSED QUARTZ
Authors: PENG J. L. , ORWA J. O. , JIANG B. , PRAWER S. , BURSILL L. A. 
Published: May 2003

Combined high-resolution transmission electron microscopy, selected area electron diffraction and parallel electron energy loss spectroscopy are used to characterise carbon nano-phases found embedded in fused quartz. These appear after implantation of 1 MeV carbon ions, followed by annealing in argon, oxygen and forming gas for 1 hour at 1100°C. For Ar, virtually all of the carbon diffuses out of the substrate with no observable carbon clusters for all doses studied. After annealing in oxygen, a crystalline CO x phase is identified at the end of range, following a dose of 5×1017 C/cm 2. Three nano-crystalline carbon phases, including diamond, appear after annealing in forming gas: these form a layer 170 nm beneath the fused quartz surface for all ion doses. The average size of these clusters and the corresponding phases depend on the ion dose; the smallest size of 5–7 nm diameter crystallise as fcc [Formula: see text] diamond following a dose of 0.5× 1017 C/cm 2, whereas clusters of 8–13 nm diameter, for a higher dose of 2× 1017 C/cm 2, have a [Formula: see text] modified phase of diamond known as n-diamond. The largest clusters, diameter 15–40 nm, for a dose of 5× 1017 C/cm 2, have the cubic P2 13 (or P4 232) structure known as i-carbon. These buried layered diamond and diamond-related materials may have applications for field emission and optical waveguide type devices.
SUPPORT VECTOR LEARNING FOR GENDER CLASSIFICATION USING AUDIO AND VISUAL CUES
Authors: WALAVALKAR L. , YEASIN M. , NARASIMHAMURTHY A. , SHARMA R. 
Published: May 2003

Computer vision systems for monitoring people and collecting valuable demographic information in a social environment is an important research problem. It is expected that such a system will play an increasingly important role in enhancing user's experience and can significantly improve the intelligibility of a human computer interaction (HCI) system. For example, a robust gender classification system can provide a basis for passive surveillance and access to a smart building using demographic information or can provide valuable consumer statistics in a public place. The option of an audio cue in addition to the visual cue promises a robust solution with high accuracy and ease-of-use in human computer interaction systems. This paper investigates gender classification using Support Vector Machines (SVMs). The visual (thumbnail frontal face) and the audio (features from speech data) cues were considered for designing the classifier. Three different representations of the data, namely, raw data, principle component analysis (PCA) and non-negative matrix factorization (NMF) were used for the experimentation with visual signal. For speech, mel-cepstral coefficient and pitch were used for the experimentation. It was found that the best overall classification rates obtained using the SVM for the visual and speech data were 95.31% and 100%, respectively, on data set collected in laboratory environment. The performance of the SVM was compared with two simple classifiers namely, the nearest prototype neighbor and the k-nearest neighbor on all feature sets. It was found that the SVM outperformed the other two classifiers on all datasets. To further understand the robustness issues, the proposed approach has been applied on a large balanced (roughly equal distribution of gender, ethnicity and age group) data-base consisting of 8000 faces collected in real world environment. While, the results are very promising it indicates more to be done to make a statistically meaningful conclusion.
NONLINEAR COOPERATIVE DYNAMICS OF LIVING NEURONS
Authors: RABINOVICH MIKHAIL I. , VARONA PABLO , ABARBANEL HENDRY D. I. 
Published: May 2003

There is a substantial body of experimental evidence that neurons often produce oscillations to achieve their functional goals. They thus behave as dynamical systems despite the fluctuations we observe due to environmental noise and imperfections in their construction. In observations of neural behavior these oscillations can appear "intrinsic" as in the rhythmical pulsing of Central Pattern Generators (CPGs) or the oscillations can arise in response to a stimulus as in the actions of projection neurons in olfactory operation or even in the dynamical response of cortex neurons. When assemblies of neurons perform oscillations, their collective behavior is determined in an essential way by both the nonlinear dynamics of the individuals in the assembly and by the architecture of the neural circuitry. The neurons inside an assembly can synchronize, possibly with an evident time lag, to produce particular patterns which control the rhythmic muscular activity of an animal, as in CPG operation. The component neurons may compete with each other in a dynamical fashion to solve the problem of pattern recognition, as in the cortex. They may collectively produce rich spatiotemporal behavior in response to specific forms of stimulus from sensory systems. This is a review of these phenomena which are discussed in language familiar in the description of nonlinear dynamical systems including synchronization and competition. We illustrate our ideas with data from experiment and model simulations for both individual neurons and assemblies of neurons.
CHAOS IN THE REORIENTATION PROCESS OF A DUAL-SPIN SPACECRAFT WITH TIME-DEPENDENT MOMENTS OF INERTIA
Authors: IÑARREA M. , LANCHARES V. 
Published: May 2003

We study the spin-up dynamics of a dual-spin spacecraft containing one axisymmetric rotor which is parallel to one of the principal axes of the spacecraft. It will be supposed that one of the moments of inertia of the platform is a periodic function of time and that the center of mass of the spacecraft is not modified. Under these assumptions, it is shown that in the absence of external torques and spinning rotors the system possesses chaotic behavior in the sense that it exhibits Smale's horseshoes. We prove this statement by means of the Melnikov method. The presence of chaotic behavior results in a random spin-up operation. This randomness is visualized by means of maps of the initial conditions with final nutation angle close to zero. This phenomenon is well described by a suitable parameter that measures the amount of randomness of the process. Finally, we relate this parameter with the Melnikov function in the absence of the spinning rotor and with the presence of subharmonic resonances.
DELAYED CONTROL OF A MOORE–GREITZER AXIAL COMPRESSOR MODEL
Authors: AERNOUTS WERNER , ROOSE DIRK , SEPULCHRE RODOLPHE 
Published: May 2003

Several feedback control laws have appeared in the literature concerning the stabilization of the nonlinear Moore–Greitzer axial compression model. Motivated by magnitude and rate limitations imposed by the physical implementation of the control law, Larsen et al. studied a dynamic implementation of the S-controller suggested by Sepulchre and Kokotović. They showed the potential benefit of implementing the S-controller through a first-order lag: while the location of the closed-loop equilibrium achieved with the static control law was sensitive to poorly known parameters, the dynamic implementation resulted in a small limit cycle at a very desirable location, insensitive to parameter variations. In this paper, we investigate the more general case when the control is applied with a time delay. This can be seen as an extension of the model with a first-order lag. The delay can either be a result of system constraints or be deliberately implemented to achieve better system behavior. The resulting closed-loop system is a set of parameter-dependent delay differential equations. Numerical bifurcation analysis is used to study this model and investigate whether the positive results obtained for the first-order model persist, even for larger values of the delay.
GENERIC HOPF BIFURCATION FROM LINES OF EQUILIBRIA WITHOUT PARAMETERS III: BINARY OSCILLATIONS
Authors: FIEDLER BERNOLD , LIEBSCHER STEFAN , ALEXANDER J. C. 
Published: May 2003

We consider discretized systems of hyperbolic balance laws. Decoupling of the flow, associated with a central difference scheme, can lead to binary oscillations — even and odd numbered grid points, separately, provide time-evolutions of two distinct, different, separate profiles. Investigating the stability of this decoupling phenomenon, we encounter Hopf-like bifurcations in the absence of parameters. With some computer-algebra assistance, we describe the qualitative behavior near these bifurcation points. In particular we observe distinct even/odd profiles which oscillate periodically in time and, for arbitrarily fine discretization, exhibit preferred, nonzero phase relationships between adjacent discretization points.
MENTAL CONDITIONS REFLECTED BY THE CHAOS OF PULSATION IN CAPILLARY VESSELS
Authors: SUMIDA TAKEO , ARIMITU YOITCHI , TAHARA TAKASHI , IWANAGA HIROAKI 
Published: May 2003

The presence of deterministic chaos has been clarified experimentally in the time series of pulsation of capillary vessels [Tsuda et al., 1992]. In this paper, first we reconfirmed the nonlinearity of the time series of pulsation of capillary vessels with surrogate data testing. Second, we investigated the characteristics of chaos of capillary data on normal subjects in different states of the autonomic nervous system and on psychiatric patients. As a result, the chaotic fluctuations decreased for the state of sympathetic dominance of normal subjects. On the contrary, the chaotic fluctuations increased for the state of parasympathetic predominance of normal subjects. We also found that the chaotic fluctuations decreased in the symptomatic phase of psychiatric patients. Interpretation of this fact is as follows. Psychiatric patients in symptomatic phase are in a condition of poor flexibility of emotion and motivated behavior in the limbic system. This condition affects the regulation of the autonomic nervous system in the hypothalamus. So it is easy to fall into the imbalance of the autonomic nervous system even with slight stress. Furthermore, in the attractor of capillary chaos we found two parts that showed the role of origin of stimulation of the sympathetic nervous system and that of stimulation of the parasympathetic nervous system, respectively. The geometrical change of topology was caused by the interplay of two parts. From our study we concluded that chaos of pulsation in capillary vessels reflected mental conditions through the autonomic nervous system.