bluuebunny/crossref_metadata_2025 huggingface dataset:
PARALLEL INCOMPLETE LU FACTORIZATION AS A PRECONDITIONER FOR KRYLOV SUBSPACE METHODS
Authors: GONZALEZ PATRICIA , CABALEIRO JOSE C. , PENA TOMAS F.
Published: April 2003

In this paper we describe a new method for the ILU(0) factorization of sparse systems in distributed memory multiprocessor architectures. This method uses a symbolic reordering technique, so the final system can be grouped in blocks where the rows are independent and the factorization of these entries can be carried out in parallel. The parallel ILU(0) factorization has been tested on the Cray T3E multicomputer using the MPI communication library. The performance was analysed using matrices from the Harwell–Boeing collection.
PARALLEL REAL-TIME OPTIMIZATION: BEYOND SPEEDUP
Authors: AKL SELIM G. , Bruda Stefan D.
Published: April 2003

Traditionally, interest in parallel computation centered around the speedup provided by parallel algorithms over their sequential counterparts. In this paper, we ask a different type of question: Can parallel computers, due to their speed, do more than simply speed up the solution to a problem? We show that for real-time optimization problems, a parallel computer can obtain a solution that is better than that obtained by a sequential one. Specifically, a sequential and a parallel algorithm are exhibited for the problem of computing the best-possible approximation to the minimum-weight spanning tree of a connected, undirected and weighted graph whose vertices and edges are not all available at the outset, but instead arrive in real time. While the parallel algorithm succeeds in computing the exact minimum-weight spanning tree, the sequential algorithm can only manage to obtain an approximate solution. In the worst case, the ratio of the weight of the solution obtained sequentially to that of the solution computed in parallel can be arbitrarily large.
LOOKING FOR Z′ BOSONS IN SUPERSYMMETRIC E6 Models THROUGH ELECTROWEAK PRECISION DATA
Authors: CHO GI-CHOL
Published: April 2003

We review constraints on additional Z′ bosons predicted in supersymmetric (SUSY) E6 models from electroweak experiments — Z-pole experiments, mW measurements and the low-energy neutral current (LENC) experiments. Four representative models — χ, ψ, η and ν — are studied in some detail. We find that the improved data of parity violation in cesium atom, which is 2.2-σ away from the standard model (SM) prediction, could be explained by the exchange of the heavy mass eigenstate Z2 in the intermediate state. The improvement over the SM can be found in χ, η, ν models, where the total χ2 of the fit to the 26 data points decreases by about five units, owing to the better fit to the atomic parity violation. Impacts of the kinetic mixing between the U (1)Y and U (1)′ gauge bosons on the χ2-analysis are studied. We find that the Z′ model with (βE,δ)=(-π/4,0.2), where βE is the mixing angle between Zχ and Zψ bosons and δ denotes the kinetic mixing, shows the most excellent fit to the data: The total χ2 decreases by about seven units as compared to the SM. We introduce the effective mixing parameter ζ, a combination of the mass and the kinetic mixing parameters. The 95% CL lower mass bound of Z2 can be shown as a function of ζ. A theoretical prediction on ζ and the U (1)′ gauge coupling gE is studied for the χ, ψ, η and ν models by assuming the minimal particle content of the SUSY E6 models.
CP VIOLATION AND BEAUTY DECAYS — A CASE STUDY OF HIGH IMPACT, HIGH SENSITIVITY AND EVEN HIGH PRECISION PHYSICS
Authors: BIGI I. I.
Published: April 2003

The narrative of these lectures contains three main threads: (i) CP violation despite having so far been observed only in the decays of neutral kaons has been recognized as a phenomenon of truly fundamental importance. The KM ansatz constitutes the minimal implementation of CP violation: without requiring unknown degrees of freedom it can reproduce the known CP phenomenology in a nontrivial way. (ii) The physics of beauty hadrons — in particular their weak decays — opens a novel window onto fundamental dynamics: they usher in a new quark family (presumably the last one); they allow us to determine fundamental quantities of the Standard Model like the b quark mass and the CKM parameters V(cb), V(ub), V(ts) and V(td); they exhibit speedy or even rapid [Formula: see text] oscillations. (iii) Heavy Quark Expansions allow us to treat B decays with an accuracy that would not have been thought possible a mere decade ago. These three threads are joined together in the following manner: (a) Huge CP asymmetries are predicted in B decays, which represents a decisive test of the KM paradigm for CP violation. (b) Some of these predictions are made with high parametric reliability, which (c) can be translated into numerical precision through the judicious employment of novel theoretical technologies. (d) Beauty decays thus provide us with a rich and promising field to search for New Physics and even study some of its salient features. At the end of it there might quite possibly be a New Paradigm for High Energy Physics. There will be some other threads woven into this tapestry: electric dipole moments, and CP violation in other strange and in charm decays.
RESUMMATION FOR HEAVY QUARK AND JET CROSS-SECTIONS
Authors: KIDONAKIS NIKOLAOS
Published: April 2003

We review the resummation of threshold logarithms for heavy quark, dijet, direct photon, and W boson production cross-sections in hadronic collisions. Beyond leading logarithms the resummed cross-section is sensitive to the color exchange in the hard scattering. The resummation is formulated at next-to-leading logarithmic or higher accuracy in terms of anomalous dimension matrices which describe the factorization of soft gluons from the hard scattering. We give results for the soft anomalous dimension matrices at one loop for the full range of partonic subprocesses involved in heavy quark, dijet, direct photon, and W boson production. We discuss the general diagonalization procedure that can be implemented for the calculation of the resummed cross-sections, and we give numerical results for top quark production at the Fermilab Tevatron. We also present analytical results for the one- and two-loop expansions of the resummed cross-sections.
CENTRAL RAPIDITY DENSITIES OF CHARGED PARTICLES AT RHIC AND LHC
Authors: ARMESTO N. , PAJARES C.
Published: April 2003

Predictions on central rapidity densities of charged particles at energies of the relativistic heavy ion collider and the large hadron collider, for central collisions between the largest nuclei that will be available at these accelerators, are reviewed. Differences among the results of the existing models are discussed in relation with their underlying physical basis and with the possibilities to discriminate them.
PEAK-TO-PEAK DYNAMICS: A CRITICAL SURVEY
Authors: CANDATEN MATTEO , RINALDI SERGIO
Published: April 2003

This paper is devoted to the study of a particular form of deterministic chaos, here called peak-to-peak dynamics (PPD). When a continuous-time system of order n has PPD, the amplitude and the time of occurrence of the next peak of its output variable can be predicted from information concerning at most two previous peaks. In other words, n differential equations can be substituted by a reduced order model, if attention is restricted to the peaks of the variable of concern. The observation of the output peaks is equivalent to the observation of the system on a Poincaré section. This is why the existence of PPD is simply related to the dimension of the attractor. The usefulness of peak-to-peak analysis for the retrieval of one-dimensional dynamics within the attractor and for the estimate of the first Liapunov exponent is demonstrated through examples. Particular attention is devoted to the possibility of exploiting the PPD reduced order models for forecasting the next peak and for the regularization of the dynamics of chaotic systems by means of piecewise constant controls.
NUCLEON STRUCTURE AND PARITY-VIOLATING ELECTRON SCATTERING
Authors: BECK DOUGLAS H. , HOLSTEIN BARRY R.
Published: April 2003

We review the area of strange quark contributions to nucleon structure. In particular, we focus on current models of strange quark vector currents in the nucleon and the associated parity-violating elastic electron scattering experiments from which vector and axial-vector currents are extracted.
SOLITON-LIKE PROPAGATION IN BIEXCITON TWO-PHOTON RESONANT REGION
Authors: SAKAI MASARU , SANO KAZUMI , KUNUGITA HIDEYUKI , EMA KAZUHIRO
Published: April 2003

We performed sub-ps pulse-propagation experiments around the biexciton two-photon resonance in CuCl, and confirmed the soliton-like propagation of exciton–polariton pulses proposed by one of us [Phys. Rev. Lett.75, 224 (1995)]. In our scheme two-photon nonlinearity compensates exciton–polariton dispersion, and pulse propagate without distortion. We compared our results with the calculated ones and obtained a good agreement between them.
IN-LINE FIBER EVANESCENT FIELD ELECTROOPTIC MODULATORS
Authors: ARFT CARL , YANKELEVICH DIEGO R. , KNOESEN ANDRÉ , MAO ERJI , HARRIS JAMES S.
Published: April 2003

Electrooptic modulators that consist of an optical fiber waveguide coupled to an electrooptic waveguide are reviewed. Desirable attributes of these devices are that the optical fiber is uninterrupted and the interaction with the electrooptic region occurs only where the optical properties are modulated. In this paper we review in-line fiber evanescent field modulators that we have implemented with electrooptic polymers and compound semiconductor quantum wells. We show that the beam propagation method can accurately simulate the behavior measured in these devices.
LIGHT-INDUCED MODIFICATION OF KINETIC MOLECULAR PROPERTIES: ENHANCEMENT OF OPTICAL KERR EFFECT IN ABSORBING LIQUIDS, PHOTOINDUCED TORQUE AND MOLECULAR MOTORS IN DYE-DOPED NEMATICS
Authors: KREUZER M. , MARRUCCI L. , PAPARO D.
Published: April 2003

In this paper we review some experimental and theoretical results on the enhancement of orientational optical nonlinearities observed in dye-doped liquids and liquid crystals. We argue that this enhancement is derived from a photoinduced modification of kinetic molecular properties. Moreover we highlight an analogy between the mechanism of this effect in nematic liquid crystals and the working principles of "molecular motors". This analogy helps us to refine the understanding of this effect and to identify the molecular parameters which play the main role. Finally we review some recent experimental results about the dependence of the optical nonlinearity enhancement on the detailed dye and host molecular structures. These results provide some insight into the light-induced phenomena taking place inside a dye molecule.
LIGHT-INDUCED CHANGES OF THE SPONTANEOUS POLARIZATION IN FERROELECTRIC LIQUID CRYSTAL PHASE
Authors: KOMITOV L. , RUSLIM C. , ICHIMURA K.
Published: April 2003

The spontaneous polarization is a very important material parameter of the ferroelectric liquid crystals. By controlling their molecular structure, the spontaneous polarization can effectively be tuned. Here, we present a study of light-induced changes of the spontaneous polarization due to photoisomerization of azo dye dissolved in the ferroelectric liquid crystal material. It was found that the spontaneous polarization was decreasing with increasing the exposure time of UV light. These changes were reversible and the spontaneous polarization recover slowly its initial value after switching off the light illumination. The photoinduced modulation of the spontaneous polarization can be implemented, for instance, in light-controlled liquid crystal optical switches.
NOISE EFFECTS ON THE ELECTROSENSE-MEDIATED FEEDING BEHAVIOR OF SMALL PADDLEFISH
Authors: RUSSELL DAVID F. , TUCKER ANNA , WETTRING BARBARA A. , NEIMAN ALEXANDER B. , WILKENS LON , MOSS FRANK
Published: April 2003

Weak electrical noise applied in the water around small paddlefish, Polyodon spathula, increases the spatial range over which they can detect and capture planktonic prey (Daphnia), demonstrating stochastic resonance at the level of an animal's feeding behavior. Here we show that optimal-amplitude (~ 0.5 μ V · cm-1) noise causes a fish to prefer more vertical angles of attack when striking at prey, as revealed in polar graphs. Increased spatial range is also seen in horizontal directions, as outlying shoulders in the probability distribution of horizontal strike distances. High levels of noise increased the distance that approaching prey travelled along the rostrum (an elongated appendage anterior to the head, functioning as an electrosensitive antenna), before the fish first showed a visible fin or body motion in response. There was no significant effect of optimal-amplitude noise on the rate of strikes, although high-amplitude noise reduced the strike rate. The behavioral data were confirmed in neurophysiological experiments demonstrating that stochastic resonance occurs in individual electroreceptors, and in fact occurs at a similar optimal noise level as in behavioral experiments. We conclude that stochastic resonance can be demonstrated in the behavior of animals, and that animals can make use of the increased sensory information available during near-threshold environmental noise.
CHARACTERISTIC TYPES OF EVOLUTION OF NOISE-INDUCED ESCAPE FLUX AT SHORT TIME SCALES
Authors: SOSKIN STANISLAV M. , SHEKA VALENTIN I. , LINNIK TATIANA L. , MANNELLA RICCARDO
Published: April 2003

Unlike the quasi-stationary escape flux, the flux on the time scales preceding the quasi-stationary stage may significantly depend on the initial state of the system. We analyze three characteristic initial stages: (i) the stable state of the noise-free system, i.e. the bottom of the potential well; (ii) the non-bottom state with given coordinate and velocity; (iii) a thermalized state. We prove rigorously and and demonstrate in simulations that, on the time scale of a period of eigenoscillation, the flux grows stepwise for cases (i) and (iii), and in an oscillatory manner for case (ii). Different steps/oscillations correspond to different topologies of the most probable escape path.
QUARTER POWER SCALING IN DYNAMICS: EXPERIMENTAL EVIDENCE FROM CELL BIOLOGY AND COGNITIVE PSYCHOLOGY
Authors: MORARIU VASILE V. , COZA AUREL
Published: April 2003

1/4 scaling of various biological variables in relation to body mass is universal in biology. Recent models provided evidence that such a scaling is a result of optimization of the processes in the system. We present evidence for 1/4 scaling in dynamical processes from two different types of experiments: fluctuation of the erythrocyte diameter and a task of random generation of series of numbers by human subjects. The time series obtained for different cells and human subjects respectively were analyzed by detrended fluctuation analysis. The exponents from different individuals presented a gaussian distribution centered at a scaling exponent equivalent to 1/4 for both types of experiments. While this proves the existence of 1/4 scaling in dynamics, it also shows that processes do not proceed equally efficient in various individuals. Consequently the deviation from the 1/4 scaling individuals can be used as a universal tool of investigation for the efficiency, or the optimization of various biological, psychological or other types of variables.
A REVIEW OF 1/f NOISE IN TERMS OF MOBILITY FLUCTUATIONS AND WHITE NOISE IN MODERN SUBMICRON BIPOLAR TRANSISTORS — BJTs AND HBTs
Authors: VANDAMME L. K. J. , TREFÁN GY.
Published: April 2003

Experimental studies on low frequency noise in bipolar junction transistors (BJT) including polysilicon emitter, hetero-junction bipolar transistors (HBTs) and silicon-germanium hetero-junction transistors (SiGe HBTs) are reviewed. The 1/f noise is treated in terms of mobility fluctuations. The validity of a new empirical relation between the 1/f noise corner frequency fc (the frequency where the 1/f noise and shot noise are equal) and the peak cutoff frequency frpeak is investigated. The experimental procedure to investigate the most dominant low-frequency noise source in the equivalent circuit is described. At medium frequencies, the white noise becomes dominant and the noise figure is calculated taking into account the emitter and base series resistance.
STOCHASTIC SCHRÖDINGER EQUATION APPROACH TO QUANTUM NOISE IN RESONANT TUNNELING CURRENT
Authors: SOLOMON WAYNE M. , SUN HE BI
Published: April 2003

We apply the quantum trajectory method to current noise in resonant tunneling devices. The results from dynamical simulation are compared with those from unconditional master equation approach. We show that the stochastic Schrödinger equation approach is useful in modeling the dynamical processes in mesoscopic electronic systems.
Role of Bombesin and Cholecystokinin Receptors in Gastric Injury Induced by Hemorrhagic Shock in the Rat
Authors: Ünlüer Erol Erden , Denizbaşi Arzu , Özyazgan Sibel , Akkan Ahmet Gökhan
Published: April 2003

Bombesin has been shown to have trophic effects on the gastrointestinal tissue. Bombesin has direct mitogenic effects besides stimulating release of gastric hormones. The aim of this study was to investigate the effect of bombesin in hemorrhagic shock-induced stress ulcers in rats, and the role of cholecystokinin (CCK) receptors in this activity. Hemorrhagic shock was created by withdrawing 3 ml blood/200 g b.w. of rats. At the end of the 1-hour hypovolemic shock period, histological analysis, gastric ulcer index, gastric myeloperoxidase activity and gastric protein oxidation levels were determined. When given before the hemorrhage, subcutaneous bombesin (10 µg/kg) reduced macroscopically gastric ulcer index (p < 0.05). Blockade of CCK-A receptors with intraperitoneal MK-329 (1 mg/kg) did not reverse bombesin-induced gastroprotection. Blockade of CCK-B receptors with intraperitoneal L-365,260 (25 mg/kg) reversed bombesin-induced gastroprotection. Blockade of the two receptors resulted in no gastroprotection at all. It is concluded that bombesin treatment attenuated hemorrhagic shock-induced stress ulcers in rats via CCK receptors.
Reperfusion-Induced Arrhythmias Are Suppressed by Inhibition of the Angiotensin II Type 1 Receptor
Authors: Yahiro Eiji , Ideishi Munehito , Wang Li Xing , Urata Hidenori , Kumagai Koichiro , Arakawa Kikuo , Saku Keijiro
Published: April 2003

We examined antiarrhythmic effects of drugs, including renin-angiotensin system (RAS) inhibitors, on reperfusion arrhythmias in rats in vivo. Anesthetized rats were subjected to 5 min of coronary occlusion and 30 min of reperfusion. Arrhythmia scores, calculated as the product of the type of arrhythmia (1 for ventricular tachycardia, 2 for ventricular fibrillation) and its duration (in seconds), were adopted to evaluate the severity of arrhythmias. Reperfusion arrhythmias were suppressed by Na+/H+ exchange inhibitor, Na+/Ca2+ exchange inhibitor and L-type Ca channel antagonist by more than 90%. Angiotensin-converting enzyme inhibitor and angiotensin II (Ang II) type 1 receptor (AT1) antagonist also modestly (by 60–70%) but significantly decreased reperfusion arrhythmias. These effects were not reversed by co-administration of bradykinin B2 receptor antagonist or AT2 antagonist, respectively. Effects of superoxide dismutase (SOD) were also examined, but SOD proved ineffective. Effects of Na+/H+ exchange inhibitor, Na+/Ca2+ exchange inhibitor and L-type Ca channel antagonist suggest a causative relationship of Ca overload in reperfusion arrhythmias. These transport systems are known to be activated by Ang II. Thus, the antiarrhythmic action of RAS inhibitors might be attributable to the inhibition of the action of Ang II via AT1.
Intracardiac Low-Energy versus Transthoracic High-Energy Direct-Current Cardioversion of Atrial Fibrillation: A Randomised Comparison
Authors: Friberg Jens , Gadsbøll Niels
Published: April 2003

Of 54 patients with long-standing atrial fibrillation (mean duration 8.3 months), 27 patients were randomised to transvenous low-energy intracardiac biphasic direct-current (DC) cardioversion (ICV) using a single-lead balloon-tipped catheter, and 27 patents were randomised to conventional high-energy transthoracic monophasic DC cardioversion (TCV). ICV was performed with increasing energy levels (7.5–10–12.5–15 J) during mild sedation. TCV was performed with 200–360–360 J during general anaesthesia. Cardioversion to sinus rhythm occurred in 93% (25/27) following ICV and in 67% (18/27) following TCV (p = 0.04). Due to the higher cardioversion rate following ICV, more patients were in sinus rhythm during 180 days of follow-up (log rank test, p = 0.04). Low-energy intracardiac cardioversion represents a highly efficacious alternative to high-energy transthoracic cardioversion.
Procalcitonin and C-Reactive Protein in Infective Endocarditis: Correlation with Etiology and Prognosis
Authors: Kocazeybek Bekir , Küçükoğlu Serdar , Öner Y. Ali
Published: April 2003

Background: The aim of this study was to investigate the diagnostic values of serum procalcitonin (PCT) and C-reactive protein (CRP) levels in infective endocarditis (IE) and to correlate them with the etiology of the disease and the prognosis of the patients. Methods: Fifty patients who were diagnosed as having IE based on Duke criteria (major and/or minor) were included in the study at the Istanbul University Cardiology Institute and Florence Nightingale Hospital. Forty patients with bacteremia (non-IE) and 50 healthy blood donors were also included in the study as the control group. During the 45 days of medical follow-up, in those patients who had a response to medical therapy based on the results of left ventricular function tests, transesophageal echocardiography (TEE) and culture, among other factors, PCT and CRP levels were measured in 5-cm3 blood samples obtained without anticoagulant when they were first admitted (day 0), as well as 24 h and 15, 30 and 45 days after admission. In the patients who had valve replacement, 5-cm3 blood samples without anticoagulant were similarly obtained on the day of admission, after 24 h and/or on the 15th day, and 1 day before and on the 2nd and 5th days after the operation. Results: In this study, a significant difference (p < 0.001) was found between the IE group and the healthy control group with respect to their serum PCT and CRP levels at the time of admission. No significant difference was found between IE and non-IE groups (p > 0.05). The sensitivity of PCT in comparison to CRP was found to be lower (84 vs. 100%); however, its specificity was determined to be higher (88 vs. 72%). The median values of serum PCT in the nonoperated and operated cases at the time of admission, after 24 h and on the 15th day were 3.71, 5.35 and 0.44, and 2.45, 4.28 and 4.22 ng/ml, respectively, and those of CRP were 9.30, 10.95 and 10.65, and 9.5, 10.9 and 10.2 mg/dl, respectively. The median values of serum PCT were found to be higher in cases with IE and non-IE related to gram-negative bacteria than those related to gram-positive bacteria (p < 0.02). This was found to be insignificant for CRP (p > 0.05). Conclusions: As a result, this study suggests that in the diagnosis of IE, it would be beneficial to use PCT, besides TEE, culture and other clinical criteria, for its high specificity and positive predictive value in comparison to CRP. This study also suggests that in determining the response to medical treatment in the follow-up period, PCT could be a more valuable parameter than CRP, as PCT has a high prognostic value and is a good indicator for valve replacement in addition to the major criteria. Furthermore, serum PCT levels may help the physician to decide on the antimicrobial therapy combination before obtaining the culture results, or in situations in which the agent could not be isolated yet.
Potentiation of Lipid Peroxidation in B16F10 and B16F1 Melanoma Cells by Caffeine, a Methylxanthine Derivative: Relationship to Intracellular Glutathione
Authors: Shukla Vivek , Gude Rajiv P.
Published: April 2003

Background: Caffeine has shown an inhibitory role in invasion and proliferation in melanoma pulmonary metastasis as well as in high-grade tissue sarcoma. However, little is known about its mechanism and possible role in metastatic cell lines. Materials and Methods: B16F10 and B16F1 cell lines of high and low metastatic potential were treated with caffeine at different time intervals with different doses. Reduced glutathione, glutathione S-transferase and lipid peroxides were estimated to evaluate the effect of caffeine. Results: Caffeine treatment showed glutathione depletion and increased lipid peroxidation with higher glutathione S-transferase activity in both B16F10 and B16F1 cell lines. However the effect of caffeine was dependent on the time factor as well as on the dose. Conclusions: Caffeine was an effective inhibitor of metastatic activity. Glutathione depletion in conjunction with increased lipid peroxidation was a potent indicator in the regulation of metastatic behavior of B16F10 and B16F1 melanoma cell lines.
In vitro and in vivo Antibacterial Activities of Telithromycin
Authors: Mikamo Hiroshige , Yin Xiang-Hua , Ninomiya Mochiyoshi , Tamaya Teruhiko
Published: April 2003

Background: Telithromycin is one of the ketolides, characterised by a 3-keto group instead of L-cladinose and a C11–C12 carbamate link by an alkyl chain to a pyridinum and imidazolium ring side chain. We evaluated in vitro and in vivo antibacterial activities of telithromycin against gynaecological pathogens. Methods: In the vitro study, the antibacterial activity of telithromycin against 180 isolates (isolated in the year 2000) of Streptococcus agalactiae (n = 33), Enterococcus faecalis (n = 22), Neisseria gonorrhoeae (n = 30), Peptostreptococcus anaerobius (n = 20), Finegoldia magna (n = 20), Bacteroides fragilis (n = 25) and Prevotella bivia (n = 30) was compared with that of erythromycin A, clarithromycin, azithromycin, ampicillin and levofloxacin. In the in vivo study, the efficacy of telithromycin was evaluated using experimental intra-abdominal abscesses in mice caused by B. fragilis (minimum inhibitory concentration of telithromycin 0.5 mg/l). Results: In the in vitro study, telithromycin inhibited more than 50% of clinical isolates of S. agalactiae, E. faecalis, N. gonorrhoeae, P. anaerobius, F. magna, B. fragilis and P. bivia at concentrations of 0.016, 0.063, 0.063, 0.032, 0.032, 0.5 and 0.25 mg/l, respectively. Telithromycin inhibited more than 90% of these clinical isolates at concentrations of 0.016, 4, 0.125, 0.063, 0.063, 4 and 1 mg/l, respectively. In the in vivo study, telithromycin inhibited abscess formation and significantly decreased viable cell counts in abscesses in comparison with the untreated group. Conclusions: These in vitro and in vivo antibacterial activities suggest that telithromycin could be a potential candidate for the treatment of bacterial infections complicated by chlamydial infection.
Drugs and Vascular Dementia
Authors: Allain Hervé , Bentue-Ferrer Danièle , Tribut Olivier , Pinel Jean-François
Published: April 2003

Between 20 and 35% of all dementias are vascular in origin, their etiology is due to cerebrovascular disease and the risk factors are known (e.g. hypertension, diabetes, smoking, or hyperlipidemia). Primary and secondary preventions are the basis of therapeutics. Symptomatic treatment is emerging, notably in the field of cognitive disorders. In that respect, monoamine oxidase inhibitors, and more recently acetylcholinesterase inhibitors, are in the process of being recognized as first-line treatments of established vascular dementia.
Growth during Early Childhood in Asthmatic Children: Relation to Inhalation Steroid Dose and Clinical Severity Score
Authors: Rotteveel J. , Potkamp J. , Holl H. , Delemarre-van de Waal H.A.
Published: April 2003

Background/Aim: While short-term studies reported a growth retardation in children with asthma treated with inhaled steroids, long-term studies described attainment of adult heights within the target height range. In the present work, we describe the growth pattern of children with asthma. Methods: In 58 children with asthma, we compared the height at age 3 years with the height at a mean age of 7.5 years during a 12-month study period. Results: No differences in growth could be detected within the study year. Children in the lowest tertile but not in other tertiles for asthma severity score and inhaled steroid dose showed a significant decrease in height standard deviation scores from age 3 to age 7.5 years. Conclusion: The decrease in height standard deviation scores might be explained by undertreatment or an individual sensitivity to inhaled steroids.
A Magnetic Stimulation Examination of Orthographic Neighborhood Effects in Visual Word Recognition
Authors: Lavidor Michal , Walsh Vincent
Published: April 2003

The split-fovea theory proposes that visual word recognition is mediated by the splitting of the foveal image, with letters to the left of fixation projected to the right hemisphere (RH) and letters to the right of fixation projected to the left hemisphere (LH). We applied repetitive transcranial magnetic stimulation (rTMS) over the left and right occipital cortex during a lexical decision task to investigate the extent to which word recognition processes could be accounted for according to the split-fovea theory. Unilateral rTMS significantly impaired lexical decision latencies to centrally presented words, supporting the suggestion that foveal representation of words is split between the cerebral hemispheres rather than bilateral. Behaviorally, we showed that words that have many orthographic neighbors sharing the same initial letters (“lead neighbors”) facilitated lexical decision more than words with few lead neighbors. This effect did not apply to end neighbors (orthographic neighbors sharing the same final letters). Crucially, rTMS over the RH impaired lead-, but not end-neighborhood facilitation. The results support the split-fovea theory, where the RH has primacy in representing lead neighbors of a written word.
Adult Brain Plasticity Elicited by Anomia Treatment
Authors: Cornelissen Katri , Laine Matti , Tarkiainen Antti , Järvensivu Tiina , Martin Nadine , Salmelin Riitta
Published: April 2003

We describe a study where a specific treatment method for word-finding difficulty (so-called contextual priming technique, which combines massive repetition priming with semantic priming) was applied with three chronic left hemisphere-damaged aphasics. Both before and after treatment, which focused on naming of a series of pictures, naming-related brain activity was measured by magnetoencephalography (MEG). Due to its excellent temporal resolution and good spatial resolution, we were able to track treatment-induced changes in cortical activity. All three subjects showed improved naming of the trained items. In all subjects, a single source area, located in the left inferior parietal lobe, close to the lesioned area, displayed statistically significant training-induced changes. This effect was of long latency as it started 300–600 msec after picture presentation. The change in activation was specific to training, as it could not be accounted for by variation of cortical dynamics associated with increased proportion of correct answers. Our interpretation is that the training effect reflects more effective phonological encoding and storage of the trained items through the engagement of a left hemispheric word-learning system. This is in line with recent functional imaging studies, which have linked left inferior parietal lobe activity to the phonological storage component of the verbal working memory, as well as with theoretical arguments stating that the primary role of the phonological loop is to acquire new words. Finally, the MEG results showed no evidence of increased right hemisphere participation following training, supporting the view that restoration of language-related networks in the damaged left hemisphere is crucial for anomia recovery.
Revisiting the comparative fallacy: a reply to Lakshmanan and Selinker, 2001
Authors: Lardiere Donna
Published: April 2003

In a recent airing of methodological concerns in the analysis of spontaneous speech samples, Lakshmanan and Selinker (2001) suggest that Lardiere (1998a) should have carried out analyses of lexical aspect and discourse grounding in determining obligatory contexts for past tense marking. Failure to do so, they argue, renders the work in question susceptible to the comparative fallacy (Bley-Vroman, 1983). In this reply I would like to briefly address some of the problems with that argument, while showing that such analyses could themselves introduce a comparative fallacy problem.
A Novel Antiinflammatory Maintains Glucocorticoid Efficacy with Reduced Side Effects
Authors: Coghlan Michael J. , Jacobson Peer B. , Lane Ben , Nakane Masaki , Lin Chun Wei , Elmore Steven W. , Kym Philip R. , Luly Jay R. , Carter George W. , Turner Russell , Tyree Curtis M. , Hu Junlian , Elgort Marc , Rosen Jon , Miner Jeffrey N.
Published: April 2003

Glucocorticoids (GCs) are commonly used to treat inflammatory disease; unfortunately, the long-term use of these steroids leads to a large number of debilitating side effects. The antiinflammatory effects of GCs are a result of GC receptor (GR)-mediated inhibition of expression of proinflammatory genes as well as GR-mediated activation of antiinflammatory genes. Similarly, side effects are most likely due to both activated and repressed GR target genes in affected tissues. An as yet unachieved pharmaceutical goal is the development of a compound capable of separating detrimental side effects from antiinflammatory activity. We describe the discovery and characterization of AL-438, a GR ligand that exhibits an altered gene regulation profile, able to repress and activate only a subset of the genes normally regulated by GCs. When tested in vivo, AL-438 retains full antiinflammatory efficacy and potency comparable to steroids but its negative effects on bone metabolism and glucose control are reduced at equivalently antiinflammatory doses. The mechanism underlying this selective in vitro and in vivo activity may be the result of differential cofactor recruitment in response to ligand. AL-438 reduces the interaction between GR and peroxisomal proliferator-activated receptor γ coactivator-1, a cofactor critical for steroid-mediated glucose up-regulation, while maintaining normal interactions with GR-interacting protein 1. This compound serves as a prototype for a unique, nonsteroidal alternative to conventional GCs in treating inflammatory disease.
Factors relating to patients' reports about hospital care for coronary heart disease in England
Authors: Jenkinson Crispin , Coulter Angela , Bruster Steve , Chandola Tarani , Jones Phil
Published: April 2003

Objectives: All health care providers in England are required to conduct surveys of their patients' experience of health care. Data from such surveys contribute to the 'star rating' performance indicators. However, there are concerns that these subjective measures may be influenced more by characteristics of patients than by true variations in the quality of care. The purpose of this paper is threefold: to determine the relationship between demographic characteristics and an index measure of patients' reported experience; to explore the extent to which patients' experiences may be accounted for by the particular National Health Service (NHS) trust they attended; and to assess how meaningful a summary index is in terms of its ability to discriminate between providers.

Methods: Data from patients in the National Survey of National Health Service Patients treated for coronary heart disease in 194 NHS trusts. Patients were sent questionnaires after discharge, with a covering letter and a prepaid stamped addressed envelope. Up to two reminders were sent to non-responders. Multi-level linear regression models were used to estimate the extent to which patients' experiences differed between trusts and the association of demographic variables with the summary index.

Results: In total, 116 872 patients were sent questionnaires, but 3399 proved to be ineligible for the survey. Responses were gained from 84 310 (74.3% of eligible respondents). Age and sex were most strongly associated with reported patients' experiences. However, the actual impact of age and sex on patients' experience is small, accounting for less than 3% of the variance. The proportion of the variance that was accounted for by the hospital trust in which patients were treated was only 5%.

Conclusions: Demographic characteristics do not appear to account for differences between hospital trusts in patients' experience of health care. However, there is considerable variation in patients' experience within each provider. This would suggest that summary indices of patients' experience should not be used to rank providers, although detailed information from patient surveys have a useful role in determining priorities for quality improvement within individual hospitals and for assessing changes over time.
Action research: a way of researching or a way of managing?
Authors: Lilford Richard , Warren Rachel , Braunholtz David
Published: April 2003

Scrutinising recent systematic reviews both on action research and on the management of change in organisations, we have made two observations which, we believe, clarify a rather amorphous literature. First, by comparing formal descriptions of each, action research cannot be clearly distinguished from many other change methodologies. This applies particularly to total quality management (TQM). Both action research and TQM are cyclical activities involving examination of existing processes, change, monitoring the apparent effects of the change and further change. Both emphasise active participation of stakeholders. The examples used to illustrate action research would serve equally well as examples of TQM and vice versa. Second, the methods used in action research are neither specific to action research nor are they of any particular kind. It therefore follows that action research, in so far as it purports to describe a unique or discrete form of research rather than a change process, is a misnomer.

Based on these observations, we make two suggestions. Organisational change should be described in terms of the steps actually taken to effect change rather than in 'terms of art' which, like the various brands of post-Freudian psychotherapy, obscure what they have in common rather than illuminate substantive differences. And the research embedded in any cyclical managerial process can have two broad (non-exclusive) aims: to help local service managers to take the next step or to assist managers in other places and in future years to make decisions. These can be described as limited (formative) and general (summative) aims. Whether, or to what extent, a research finding is generalisable across place and time is a matter of judgement and turns on the form of the research and on its context; it is completely independent of whether or not the research was carried out within a cycle of managerial action currently described by terms such as action research or TQM.
Novel Route to Cubic Boron Nitride Dendritic Nanostructures under Electron Beam Irradiation
Authors: Yin L.‐W. , Li M.‐S. , Liu Y.‐X. , Xu B. , Sui J.‐L. , Qi Y.‐X.
Published: April 2003

The growth of c‐BN dendritic nanostructures (see Figure) has been investigated in situ using a combination of characterization techniques. It is concluded that the electron beam irradiation induced nucleation and growth of the nanostructures in vacuum is closely related to the nanoarches at the edge of the h‐BN starting material. A solid‐sate mechanism different from the traditional one for BN nanostructure growth from the gas phase is proposed.
Erhöhtes Krebsrisiko bei Störungen der inneren Uhr
Authors: Brennicke Axel
Published: April 2003

Innere Uhren steuern unser Leben, ohne dass wir uns dessen bewusst werden. Der Wecker steht jeden Morgen auf 7 Uhr, aber wir wachen schon eine Minute vor 7 auf und hören die Schaltung leise einrasten: Unsere innere Uhr hat uns pünktlich geweckt. Jetzt berichten Wissenschaftler, dass bei Mäusen sogar die Anfälligkeit für Krebs durch die innere Uhr reguliert wird.
Aktuelle Informationen zum Drogenkonsum: Cannabis, Ecstasy, Heroin & Co.
Authors: Croissant Bernhard , Croissant Daniela , Mann Karl
Published: April 2003

Eine nicht zu unterschätzende Anzahl der deutschen Jugendlichen beginnt schon früh mit dem Konsum von Drogen: Vom 18. Lebensjahr an hat bereits mehr als ein Drittel aller Jugendlichen Drogenerfahrung. Die meisten späteren Konsumenten illegaler Drogen (84 Prozent) machen erste einschlägige Erfahrungen im Alter von 14 bis 19 Jahren. Das Abhängigkeitspotenzial psychotroper Substanzen ist sehr unterschiedlich. Nicht jede Substanz, die eine psychische Abhängigkeit hervorruft, bewirkt automatisch auch eine physische Abhängigkeit. Umgekehrt allerdings besteht bei physischer Abhängigkeit meistens eine psychische Abhängigkeit. Eine physische Abhängigkeit ist im Wesentlichen durch ein körperliches Entzugssyndrom gekennzeichnet, welches dazu führt, dass ein großes Verlangen besteht, diese Substanz erneut zu konsumieren. Bei einer psychischen Abhängigkeit empfindet die Person die Notwendigkeit, in bestimmten Abständen eine entsprechende Substanz zu konsumieren, um bestimmte angenehme Wirkungen zu erzielen oder unangenehme Empfindungen zu vermeiden, die beim Nachlassen der Substanzwirkung auftreten würden.
Johann Friedrich Miescher
Authors: Dahm Ralf
Published: April 2003

Am 25. April 1953 veröffentlichte die Fachzeitschrift „Nature”︁ einen kurzen Aufsatz von zwei jungen Forschern aus Cambridge. In ihm beschrieben der amerikanische Biologe James Watson und der britische Physiker Francis Crick zum ersten Mal die korrekte Struktur der DNA. Entdeckt wurde die Erbsubstanz jedoch fast 100 Jahre vor der Entschlüsselung ihrer Struktur: Bereits im Jahr 1869 isolierte der junge Schweizer Mediziner Johann Friedrich Miescher in der ehemaligen Küche des Tübinger Schlosses die DNA.
Kieselalgenschalen — Spielerei oder Anpassung?
Authors: Hamm Christian
Published: April 2003

Diatomeen (Kieselalgen) besitzen komplexe, meist sehr ästhetische Schalen aus Silikat, einem glasartigen Material. Es wird seit langem diskutiert, ob diese in zahlreichen Arten unterschiedlich ausgeprägten Strukturen eine bestimmte Funktion haben. Neue Untersuchungen zeigen, dass eine günstige Kombination von Material und Struktur die Schalen so stabil macht, dass sie einen effektiven Schutz vor Fressfeinden bieten.
Mass equidistribution for Hecke eigenforms
Authors: Luo Wenzhi , Sarnak Peter
Published: April 2003

In this work, we study the mass equidistribution for holomorphic Hecke eigenforms and establish, by employing incomplete Poincaré series and the Petersson formula, sharp equidistribution results when the average is performed over intervals much shorter than before. A key feature is the analysis of the off‐diagonal terms that result from this shortening of intervals. © 2003 Wiley Periodicals, Inc.
Pseudoathetosis in a patient with leprosy
Authors: Misra Usha Kant , Kalita Jayantee , Mahadevan Anita , Shankar Susarla Krishna
Published: April 2003

A 35‐year‐old man with borderline tuberculoid leprosy developed Type I lepra reaction 12 days after anti‐leprosy treatment. There was acute worsening of neuropathic symptoms and skin lesions. He developed severe sensory ataxia and pseudoathetosis resulting in marked disability. His symptoms significantly improved on corticosteroid therapy. © 2003 Movement Disorder Society
Dielectric properties of self‐catalytic interpenetrating polymer network based on modified bismaleimide and cyanate ester resins
Authors: Fan Jing , Hu Xiao , Yue Chee Yoon
Published: April 2003

Bismaleimide (BMI) resins with good thermal stability, fire resistance, low water absorption, and good retention of mechanical properties at elevated temperatures, especially in hot/wet environments, have attracted more attention in the electronic and aerospace industries. However, their relatively high dielectric constant limits their application in the aforementioned fields. In this work, a new promising approach is presented that consists of the formation of a self‐catalytic thermoset/thermoset interpenetrating polymer network. Interpenetrating polymer networks (IPNs) based on modified BMI resin (BMI/DBA) and cyanate ester (b10) were synthesized via prepolymerization followed by thermal curing. The self‐catalytic curing mechanism of BMI/DBA‐CE IPN resin systems was examined by differential scanning calorimetry. The dielectric properties of the cured BMI/DBA‐CE IPN resin systems were evaluated by a dielectric analyzer and shown in dielectric properties‐temperature‐log frequency three‐dimensional plots. The effect of temperature and frequency on the dielectric constant of the cured BMI/DBA‐CE IPN resin systems is discussed. The composition effect on the dielectric constant of the cured IPN resin systems was analyzed on the basis of Maxwell's equation and rule of mixture. The obtained BMI/DBA‐CE IPN resin systems have the combined advantages of low dielectric constant and loss, high‐temperature resistance, and good processability, which have many applications in the microelectronic and aerospace industries. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1123–1134, 2003
High‐modulus, high‐strength, thick polypropylene monofilament production: Response surface analysis approach
Authors: Lim Jung Yul , Kim Sang Yong
Published: April 2003

Response surface analysis was used in optimizing spinning and drawing conditions for the production of a high‐modulus, high‐strength, thick polypropylene (PP) monofilament. Rotatable octagonal central composite design was adopted with two independent variables (take‐up velocity and draw ratio), and variations in the diameter, tensile modulus, and tenacity of the PP monofilament were observed. Quadratic response surface functions described the variations in those properties with quite high correlation coefficients. Canonical analysis combined with contour plots revealed the variation sensitivity: the diameter varied more markedly with the take‐up velocity, and the tensile modulus varied somewhat equally with the two variables, whereas the tenacity varied more markedly with the draw ratio. From such contour plots, the optimum processing conditions for desired properties were predicted without intensive structural analysis. Case studies showed that under the suggested processing conditions, the PP monofilament fulfilled the property requirements, such as a tensile modulus of 10.4 GPa and a tenacity of 672 MPa with a diameter still above 400 μm. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1175–1182, 2003
Macroscopic quantum behavior of superconducting quantum interference devices
Authors: Castellano M.G.
Published: April 2003

Superconducting quantum interference devices (SQUIDs) are made by a superconducting loop interrupted by one or more Josephson junctions. They are described in terms of a macroscopic variable, the magnetic flux, which shows quantum effects such as tunnelling through a potential barrier. Besides making up the source of a quantum state, SQUIDs also provide the instruments necessary for its probing: as a fact, SQUID based magnetometers have a sensitivity approaching the quantum limit. In this paper I will review the working principle of these devices and illustrate the system of SQUIDs realized in my group to test the quantum behavior at a macroscopic level.