bluuebunny/crossref_metadata_2025 huggingface dataset:
Approaches to the factory of the future. An empirical taxonomy
Authors: Boyer Kenneth K. , Ward Peter T. , Leong G.Keong
Published: April 2003

An empirical analysis of the patterns in which companies invest in advanced manufacturing technologies (AMTs) such as computer‐aided design, computer‐aided manufacturing, and flexible manufacturing systems is presented. Data for this analysis are gathered from 202 manufacturing plants chosen from industries generally considered to have relatively high investments in technology.

Three general types of AMTs are identified from the literature: design, manufacturing, and administrative. Multiple item scales are developed to measure each type of AMT. These scales are shown to be reliable instruments, and are used to develop an empirical taxonomy which validates existing conceptual typologies of AMTs. A cluster analysis reveals four distinct groups of companies with respect to their approaches toward investing in AMTs. TRADITIONALISTS do not invest heavily in any of the three types of AMTs. GENERALISTS have moderate investments in each technology type. HIGH INVESTORS have the highest investment in each of the three technology types. The most interesting group may well be the DESIGNERS, which have low investments for manufacturing and administrative AMTs, but have the second highest investment in design‐related AMTs.

An analysis of the four technology groups reveals that while plants do differ in terms of plant size and integration, they do not differ significantly in terms of industry membership or performance. This suggests that successful firms can be found in each of the groups and that good strategies may be found that are consistent with each of these approaches. Therefore, the taxonomy is fairly robust, and further research must analyze companies within these groupings in order to identify the contingencies or other factors that may act in conjunction with technology to separate high and low performing firms. The data from our study clearly suggest that investments in technology alone are not a causal factor for performance improvement.
Corporate governance and market valuation of capital and R&D investments
Authors: Chung Kee H. , Wright Peter , Kedia Ben
Published: April 2003

In this study, we examine how corporate governance structure affects market valuation of capital and R&D investments. We employ three empirical proxies of corporate governance—analyst following, board composition, and institutional holdings, and study whether market valuation of corporate investments varies with governance structure. Our results show that the market valuation of the firm's capital and R&D investments depends critically on analyst following and board composition, but not on institutional holdings.
Time Integration Questionnaire
Authors: DrakuliĆ Bogdan , TenjoviĆ Lazar , LeČiĆ-Tosevski Dusica
Published: April 2003

Summary: The paper presents the Time Integration Questionnaire (TIQ) for the assessment of subjective time experience, constructed in a phenomenologically enriched form, as compared to those reduced to succession and three basic dimensions: the past, the present, and the future. In the formulation of items we utilized the questionnaire empirical procedure, commencing from 233 dictionary terms of the meaning of time. Based on the statistical analyses of 213 university students' responses to the initial version of the questionnaire, we constructed eight preliminary scales to assess tentative aspects of time organization of psychological functioning: Speed, Repetition, Continuity, Stability, Retroversion, Progression, Contiguity, and Anteversion. Because exploratory factor analysis of 73 items from the preliminary questionnaire on the sample of 473 medical students did not support eight preliminary scales and rather suggested a two-factor structure of the questionnaire, new final scales were proposed: Succession and Integration. The Succession scale comprises mainly the items from the preliminary Speed, Repetition, and Continuity scales, whereas the Integration scale encompasses items from the preliminary Progression, Contiguity, and Anteversion scales. Factor loadings of the items from the final Succession and Integration scales on the new sample of 97 adults were consistent with item assignment to two respective scales. Indices of internal, factorial, and concurrent validity of Succession and Integration Scales as obtained on the samples of 97 healthy adults and 85 subjects with psychiatric diagnosis further justified two final scale construction as a better solution in comparison with eight preliminary scales. The Temporal Integration Questionnaire, in its present form, may be utilized primarily in research, while the justification of its usage in psychodiagnostics would depend on a future results achieved in the various homogeneous clinical populations.
Ketone bodies disturb fatty acid handling in isolated cardiomyocytes derived from control and diabetic rats
Authors: HASSELBAINK Danny M. , GLATZ Jan F. C. , LUIKEN Joost J. F. P. , ROEMEN Theo H. M. , VAN der VUSSE Ger J.
Published: April 2003

According to the current paradigm, fatty acid (FA) utilization is increased in the diabetic heart. Since plasma levels of competing substrates such as ketone bodies are increased during diabetes, the effect of those substrates on cardiac FA handling was explored. Cardiomyocytes were isolated from control and streptozotocin-treated diabetic rats and incubated with normal (80 μM) and elevated (160 μM) palmitate concentrations in the absence or presence of ketone bodies, including acetoacetate (AcAc). Comparing control cardiomyocytes under normal conditions (80 μM, no AcAc) with diabetic cardiomyocytes (160 μM, 3 mM AcAc) showed that palmitate uptake was increased from 35.2 ± 4.8 to 60.2 ± 14.0 nmol · 3 min−1 · g wet weight−1 respectively. Under these conditions, palmitate oxidation rates were comparable (58.9 ± 23.6 versus 53.2 ± 18.5 nmol · 30 min−1 · g wet weight−1). However, in the absence of AcAc, palmitate oxidation was significantly enhanced in diabetic cardiomyocytes, indicating that ketone bodies are able to suppress cardiac FA oxidation in diabetes. The concomitantly increased FA uptake in diabetic cells, mainly due to the elevated extracellular FA levels, may be responsible for the accumulation of FA and triacylglycerol, as observed in the diabetic heart in situ.
Stimulation of glycogen synthesis by heat shock in L6 skeletal-muscle cells: regulatory role of site-specific phosphorylation of glycogen-associated protein phosphatase 1
Authors: MOON Byoung , DUDDY Noreen , RAGOLIA Louis , BEGUM Najma
Published: April 2003

Recent evidence suggests that glycogen-associated protein phosphatase 1 (PP-1G) is essential for basal and exercise-induced glycogen synthesis, which is mediated in part by dephosphorylation and activation of glycogen synthase (GS). In the present study, we examined the potential role of site-specific phosphorylation of PP-1G in heat-shock-induced glycogen synthesis. L6 rat skeletal-muscle cells were stably transfected with wild-type PP-1G or with PP-1G mutants in which site-1 (S1) Ser48 and site-2 (S2) Ser67 residues were substituted with Ala. Cells expressing wild-type and PP-1G mutants, S1, S2 and S1/S2, were examined for potential alterations in glycogen synthesis after a 60min heat shock at 45°C, followed by analysis of [14C]glucose incorporation into glycogen at 37°C. PP-1G S1 mutation caused a 90% increase in glycogen synthesis on heat-shock treatment, whereas the PP-1G S2 mutant was not sensitive to heat stress. The S1/S2 double mutant was comparable with wild-type, which showed a 30% increase over basal. Heat-shock-induced glycogen synthesis was accompanied by increased PP-1 and GS activities. The highest activation was observed in S1 mutant. Heat shock also resulted in a rapid and sustained Akt/ glycogen synthase kinase 3β (GSK-3β) phosphorylation. Wortmannin blocked heat-shock-induced Akt/GSK-3β phosphorylation, prevented 2-deoxyglucose uptake and abolished the heat-shock-induced glycogen synthesis. Muscle glycogen levels regulate GS activity and glycogen synthesis and were found to be markedly depleted in S1 mutant on heat-shock treatment, suggesting that PP-1G S1 Ser phosphorylation may inhibit glycogen degradation during thermal stimulation, as S1 mutation resulted in excessive glycogen synthesis on heat-shock treatment. In contrast, PP-1G S2 Ser phosphorylation may promote glycogen breakdown under stressful conditions. Heat-shock-induced glycogenesis appears to be mediated via phosphoinositide 3-kinase/Akt-dependent GSK-3β inactivation as well as phosphoinositide 3-kinase-independent PP-1 activation.
A role for c-Jun N-terminal kinase 1 (JNK1), but not JNK2, in the beta-amyloid-mediated stabilization of protein p53 and induction of the apoptotic cascade in cultured cortical neurons
Authors: FOGARTY Marie P. , DOWNER Eric J. , CAMPBELL Veronica
Published: April 2003

β-Amyloid (Aβ) peptide has been shown to induce neuronal apoptosis; however, the mechanisms underlying Aβ-induced neuronal cell death remain to be fully elucidated. The stress-activated protein kinase, c-Jun N-terminal kinase (JNK), is activated in response to cellular stress and has been identified as a proximal mediator of cell death. In the present study, expression of active JNK was increased in the nucleus and cytoplasm of Aβ-treated cells. Evaluation of the nature of the JNK isoforms activated by Aβ revealed a transient increase in JNK1 activity that reached its peak at 1 h and a later activation (at 24 h) of JNK2. The tumour suppressor protein, p53, is a substrate for JNK and can serve as a signalling molecule in apoptosis. In cultured cortical neurons, we found that Aβ increased p53 protein expression and phosphorylation of p53 at Ser15. Thus it appears that Aβ increases p53 expression via phosphorylation-mediated stabilization of the protein. Given the lack of availability of a JNK inhibitor that can distinguish between JNK1- and JNK2-mediated effects, we employed antisense technology to deplete cells of JNK1 or JNK2 selectively. Using this strategy, the respective roles of JNK1 and JNK2 on the Aβ-mediated activation of the apoptotic cascade (i.e. p53 stabilization, caspase 3 activation and DNA fragmentation) were examined. The results obtained demonstrate a role for JNK1 in the Aβ-induced stabilization of p53, activation of caspase 3 and DNA fragmentation. In contrast, depletion of JNK2 had no effect on the proclivity of Aβ to activate capase 3 or induce DNA fragmentation. These results demonstrate a significant role for JNK1 in Aβ-mediated induction of the apoptotic cascade in cultured cortical neurons.
Nitric oxide donors inhibit formation of the Apaf-1/caspase-9 apoptosome and activation of caspases
Authors: ZECH Birgit , KÖHL Roman , von KNETHEN Andreas , BRÜNE Bernhard
Published: April 2003

Caspases are critical for the initiation and execution of apoptosis. Nitric oxide (NO) or derived species can prevent programmed cell death in several cell types, reportedly through S-nitrosation and inactivation of active caspases. Although we find that S-nitrosation of caspases can occur in vitro, our study questions whether this post-translational modification is solely responsible for NO-mediated inhibition of apoptosis. Indeed, using Jurkat cells as a model system, we demonstrate that NO donors block Fas- and etoposide-induced caspase activation and apoptosis (downstream of mitochondrial membrane depolarization) and cytochrome c release. However, caspase activity was not restored by the strong reducing agent dithiothreitol, as predicted for S-nitrosation reactions, thereby excluding active-site-thiol modification of caspases as the only anti-apoptotic mechanism of NO donors in cells. Rather, we observed that processing of procaspases-9, −3 and −8 was decreased due to ineffective formation of the Apaf-1/caspase-9 apoptosome. Gel-filtration and in vitro binding assays indicated that NO donors inhibit correct assembly of Apaf-1 into an active approx. 700 kDa apoptosome complex, and markedly attenuate caspase-recruitment domain (CARD)–CARD interactions between Apaf-1 and procaspase-9. Therefore we suggest that NO or a metabolite acts directly at the level of the apoptosome and inhibits the sequential activation of caspases-9, −3 and −8, which are required for both stress- and receptor-induced death in cells that use the mitochondrial subroute of cell demise.
Attenuation of glucocorticoid functions in an Anx-A1-/- cell line
Authors: CROXTALL Jamie D. , GILROY Derek W. , SOLITO Egle , CHOUDHURY Qamrul , WARD Barbara J. , BUCKINGHAM Julia C. , FLOWER Rod J.
Published: April 2003

The Ca2+- and phospholipid-binding protein Anx-A1 (annexin 1; lipocortin 1) has been described both as an inhibitor of phospholipase A2 (PLA2) activity and as a mediator of glucocorticoid-regulated cell growth and eicosanoid generation. Here we show that, when compared with Anx-A1+/+ cells, lung fibroblast cell lines derived from the Anx-A1−/− mouse exhibit an altered morphology characterized by a spindle-shaped appearance and an accumulation of intracellular organelles. Unlike their wild-type counterparts, Anx-A1−/− cells also overexpress cyclo-oxygenase 2 (COX 2), cytosolic PLA2 and secretory PLA2 and in response to fetal calf serum, exhibit an exaggerated release of eicosanoids, which is insensitive to dexamethasone (10−8– 10−6 M) inhibition. Proliferation and serum-induced progression of Anx-A1+/+ cells from G0/G1 into S phase, and the associated expression of extracellular signal-regulated kinase 2 (ERK2), cyclin-dependent kinase 4 (cdk4) and COX 2, is strongly inhibited by dexamethasone, whereas Anx-A1−/− cells are refractory to the drug. Loss of the response to dexamethasone in Anx-A1−/− cells occurs against a background of no apparent change in glucocorticoid receptor expression or sensitivity to non-steroidal anti-inflammatory drugs. Taken together, these observations suggest strongly that Anx-A1 functions as an inhibitor of signal-transduction pathways that lead to cell proliferation and may help to explain how glucocorticoids regulate these processes.
Biosynthesis of 2-acetamido-2,6-dideoxy-l-hexoses in bacteria follows a pattern distinct from those of the pathways of 6-deoxy-l-hexoses
Authors: KNEIDINGER Bernd , LAROCQUE Suzon , BRISSON Jean-Robert , CADOTTE Nicolas , LAM Joseph S.
Published: April 2003

6-Deoxy-l-hexoses have been shown to be synthesized from dTDP-d-glucose or GDP-d-mannose so that the gluco/galacto-configuration is converted into the manno/talo-configuration, and manno/talo is switched to gluco/galacto. Our laboratory has been investigating the biosynthesis of 2-acetamido-2,6-dideoxy-l-hexoses in both Gram-positive and Gram-negative bacteria, and in a recent paper we described the biosynthesis of the talo (pneumosamine) and galacto (fucosamine) derivatives from UDP-d-N-acetylglucosamine a 2-acetamido sugar [Kneidinger, O'Riordan, Li, Brisson, Lee and Lam (2003) J. Biol. Chem. 278, 3615–3627]. In the present study, we undertake the task to test the hypothesis that UDP-d-N-acetylglucosamine is the common precursor for the production of 2-acetamido-2,6-dideoxy-l-hexoses in the gluco-, galacto-, manno- and talo-configurations. We present data to reveal the steps for the biosynthesis of the gluco (quinovosamine)- and manno (rhamnosamine)-configured compounds. The corresponding enzymes WbvB, WbvR and WbvD from Vibrio cholerae serotype O37 have been overexpressed and purified to near homogeneity. The enzymic reactions have been analysed by capillary electrophoresis and NMR spectroscopy. Our data have revealed a general feature of reaction cascades due to the three enzymes. First, UDP-d-N-acetylglucosamine is catalysed by the multi-functional enzyme WbvB, whereby dehydration occurs at C-4, C-6 and epimerization at C-5, C-3 to produce UDP-2-acetamido-2,6-dideoxy-l-lyxo-4-hexulose. Secondly, this intermediate is converted by the C-4 reductase, WbvR, in a stereospecific reaction to yield UDP-2-acetamido-l-rhamnose. Thirdly, UDP-2-acetamido-l-rhamnose is epimerized at C-2 to UDP-2-acetamido-l-quinovose by WbvD. Interestingly, WbvD is also an orthologue of WbjD, but not vice versa. Incubation of purified WbvD with UDP-2-acetamido-2,6-dideoxy-l-talose and analysing the reaction products by capillary electrophoresis revealed the same product peak as when WbjD was used. This sugar nucleotide is a specific substrate for WbjD and is a C-4 epimer of UDP-2-acetamido-l-rhamnose.
Safety and efficacy of low-energy cardioversion of 500 patients using two different techniques
Authors: Andraghetti A. , Scalese M.
Published: April 2003

Aim

To present some safety and efficacy issues of low-energy internal cardioversion of chronic atrial fibrillation from 500 consecutive procedures performed with two different techniques, using either two single-coil catheters, or a single twin-coil catheter.

Methods and Results

Low-energy internal cardioversion was carried out in 368 patients by means of two defibrillation catheters: the former was positioned in the right atrium and the latter either in the left pulmonary artery (212 patients), or in the distal coronary sinus (156 patients). In the remaining 132 patients, a single twin-coil catheter was positioned with the distal coil either in the pulmonary artery (75 patients) or in the coronary sinus (57 patients), while the proximal coil was in the right atrium. The external defibrillator delivered truncated biphasic shocks (6/6 ms, tilt 50%), with a voltage of 10–400 V. In 283 patients (57%) external cardioversion had been unsuccessfully tried before low-energy internal cardioversion. After a total of 1118 shocks, the overall success rate was 92·2% (91·3% with two catheters and 94·7% with the single catheter); the success rate was 93·4 and 91·3% with the coronary sinus and the pulmonary artery approach, respectively. The mean energy used was 6·5±3·4 J (voltage: 320±45 V); no difference was found between the twin catheter (6·3±3·1 J) and the single catheter approach (6·9±3·7 J), while the coronary sinus configuration required a significantly lower energy than the pulmonary artery configuration (5·6±2·9 vs 7·2±3·8 J, P<0·05). The duration of the current atrial fibrillation episode was the only clinical characteristic statistically different between the 461 successfully cardioverted patients and the 39 failures (295 vs 727 days, P<0·01). No complication was recorded during or after the delivery of the therapy; no procedure had to be terminated because of patient's intolerance.

Conclusions

Low-energy internal cardioversion is a safe and effective procedure for converting chronic atrial fibrillation, confirmed by this large multicentre experience. The newly available twin-coil catheter seems to achieve a slightly better success rate compared with the traditional two-catheter technique, and is associated with the same safety profile.
Simulation studies of the role of reconnection in the “current hole” experiments in the Joint European Torus
Authors: Breslau J. A. , Jardin S. C. , Park W.
Published: April 2003

Injection of lower hybrid current drive into the current ramp-up phase of Joint European Torus (JET) discharges has been observed to produce an annular current distribution with a core region of essentially zero current density [Hawkes et al., Phys. Rev. Lett. 87, 115001 (2001)]. Similar “current holes” have been observed in Japan Atomic Energy Research Institute Tokamak 60 Upgrade discharges with off-axis current drive supplied by bootstrap current [T. Fujita et al., Phys. Rev. Lett. 87, 245001 (2001)]. In both cases, the central current does not go negative, although current diffusion calculations indicate that there is sufficient noninductive current drive for this to occur. This is explained by the multilevel 3D code (M3D) nonlinear 2D and 3D resistive magnetohydrodynamic (MHD) simulations in toroidal geometry, which predict that these discharges undergo n=0 reconnection events—“axisymmetric sawteeth”—that redistribute the current to hold its core density near zero. Unlike conventional sawteeth, these events retain the symmetry of the equilibrium, and thus are best viewed as a transient loss of equilibrium caused when an ι=0 rational surface enters the plasma. If the current density profile has a central minimum, this surface will enter on axis; otherwise it will enter off-axis. In the first case, the reconnection is limited to a small region around the axis and clamps the core current at zero. In the second case, more typical of the JET experiments, the core current takes on a finite negative value before the ι=0 surface appears, resulting in discrete periodic axisymmetric sawtooth events with a finite minor radius. Interpretation of the simulation results is given in terms of analytic equilibrium theory, and the relation to conventional sawteeth and to a recent reduced-MHD analysis of this phenomenon in cylindrical geometry [Huysmans et al., Phys. Rev. Lett. 87, 245002 (2001)] is discussed.
Improved models for the dynamical overstability of radiative blast waves
Authors: Laming J. Martin , Grun Jacob
Published: April 2003

Further developments in atomic physics calculations of radiative cooling designed to interpret experimental observations of overstability in radiating decelerating blast waves by Grun et al. [Phys. Rev. Lett. 66, 2738 (1991)] are described. A previous paper on the subject [Laming and Grun, Phys. Rev. Lett. 89, 125002 (2002)] showed that in order to be overstable, shocked gas must cool significantly in a distance downstream from the shock similar to the width of the shock transition itself. In this paper a more realistic model for the shock jump is employed, and significantly improved agreement between theory and experiment is found.
Experimental characterization of coherent, radially-sheared zonal flows in the DIII-D tokamak
Authors: McKee G. R. , Fonck R. J. , Jakubowski M. , Burrell K. H. , Hallatschek K. , Moyer R. A. , Rudakov D. L. , Nevins W. , Porter G. D. , Schoch P. , Xu X.
Published: April 2003

The application of time-delay-estimation techniques to two-dimensional measurements of density fluctuations, obtained with beam emission spectroscopy in DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] plasmas, has provided temporally and spatially resolved measurements of the turbulence flow-field. Features that are characteristic of self-generated zonal flows are observed in the radial region 0.85⩽r/a⩽1.0. These features include a coherent oscillation (approximately 15 kHz) in the poloidal flow of density fluctuations that has a long poloidal wavelength, possibly m=0, narrow radial extent (krρI<0.2), and whose frequency varies monotonically with the local temperature. The approximate effective shearing rate, dvθ/dr, of the flow is of the same order of magnitude as the measured nonlinear decorrelation rate of the turbulence, and the density fluctuation amplitude is modulated at the frequency of the observed flow oscillation. Some phase coherence is observed between the higher wavenumber density fluctuations and low frequency poloidal flow fluctuations, suggesting a Reynolds stress contribution. These characteristics are consistent with predicted features of zonal flows, specifically identified as geodesic acoustic modes, observed in 3-D Braginskii simulations of core/edge turbulence.
NIMROD: A computational laboratory for studying nonlinear fusion magnetohydrodynamics
Authors: Sovinec C. R. , Gianakon T. A. , Held E. D. , Kruger S. E. , Schnack D. D. ,   NIMROD Team
Published: April 2003

Nonlinear numerical studies of macroscopic modes in a variety of magnetic fusion experiments are made possible by the flexible high-order accurate spatial representation and semi-implicit time advance in the NIMROD simulation code [A. H. Glasser et al., Plasma Phys. Controlled Fusion 41, A747 (1999)]. Simulation of a resistive magnetohydrodynamics mode in a shaped toroidal tokamak equilibrium demonstrates computation with disparate time scales, simulations of discharge 87009 in the DIII-D tokamak [J. L. Luxon et al., Plasma Physics and Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. I, p. 159] confirm an analytic scaling for the temporal evolution of an ideal mode subject to plasma-β increasing beyond marginality, and a spherical torus simulation demonstrates nonlinear free-boundary capabilities. A comparison of numerical results on magnetic relaxation finds the n=1 mode and flux amplification in spheromaks to be very closely related to the m=1 dynamo modes and magnetic reversal in reversed-field pinch configurations. Advances in local and nonlocal closure relations developed for modeling kinetic effects in fluid simulation are also described.
Relativistic effects on intense laser beam propagation in plasma channels
Authors: Hafizi B. , Ting A. , Hubbard R. F. , Sprangle P. , Peñano J. R.
Published: April 2003

Propagation characteristics of a radiation beam in a preformed, tapered plasma channel are analyzed by means of an envelope equation for the beam spot size. The model allows for relativistic focusing and ponderomotive channeling, radial and axial density gradients, and is valid for arbitrary intensity. The characteristics of laser beam propagation are shown to be governed by two parameters, the ratio of laser power to the critical power for relativistic focusing, and a dimensionless focusing strength parameter that includes contributions from both relativistic and channel focusing. The envelope equation provides a unified approach for exploring diverse applications such as designing a tapered laser wakefield accelerator or a plasma lens. The model is employed in interpretation of pump–probe laser propagation experiments and an x-ray source experiment. Full-scale simulations of a plasma channel lens are presented and shown to be in excellent agreement with the analytical results.
Emission spectra of free base phthalocyanine in superfluid helium droplets
Authors: Lehnig R. , Slenczka A.
Published: April 2003

We report on the electronic emission spectra of free-base phthalocyanine doped into superfluid He4 droplets. The emission spectra of phthalocyanine obtained upon vibronic excitation show a doubling of all lines, absent in the gas phase [Fitch, Wharton, and Levy, J. Chem. Phys. 70, 2018 (1979)]. Similar features found for Mg-phthalocyanine in He4 droplets suggest that this doubling is due to the helium environment. Quantized relaxation states of the first helium layer surrounding the embedded molecule are discussed as likely causes of the doubling.
The effective valence shell Hamiltonian for spin-orbit coupling
Authors: Sun Hosung , Freed Karl F.
Published: April 2003

The size extensive, ab initio effective valence shell Hamiltonian method, which is based on quasidegenerate many-body perturbation theory, has been extended to treat spin-orbit coupling in atoms or molecules. Just as the exact projection of the nonrelativistic Hamiltonian into a prechosen valence space enables deriving the multireference perturbation expansion for the exact effective valence shell Hamiltonian, the addition of the Breit–Pauli spin-orbit operator to the original Hamiltonian (as an extra perturbation) enables the use of quasidegenerate many-body perturbation theory to produce the energy independent effective spin-orbit coupling operator that acts within the prechosen valence space. To assess the accuracy of the proposed method, test calculations are performed for the spin-orbit splittings in the valence states of C, Si, Ge, CH, SiH, and GeH and their positive ions using the one-electron spin-orbit approximation with standard values of the effective nuclear charge. The computed spin-orbit splittings are generally in good agreement with experiment and with the few available ab initio computations. Deviations appear in certain cases where the omitted coupling to Rydberg states is known to be relevant. One advantage of the method is that the spin-orbit coupling energies of all valence states for both the neutral species and its ions are simultaneously determined with a similar accuracy from a single computation of the effective spin-orbit coupling operator. Thus, fine structure splittings are predicted for a number of states of each system for which neither experiment nor theory is available. Another advantage stems from the fact that all off-diagonal spin-orbit matrix elements are also obtained.
Multi-keV x-ray conversion efficiency in laser-produced plasmas
Authors: Back C. A. , Davis J. , Grun J. , Suter L. J. , Landen O. L. , Hsing W. W. , Miller M. C.
Published: April 2003

X-ray sources are created at the Nova and Omega laser by irradiating a confined volume of Ar and Xe gas. The gas is heated by 20–35 kJ of 0.35 μm laser light and becomes a highly ionized mm-sized x-ray source which emits K-shell or L-shell x rays. The radiator is “underdense,” meaning that the initial electron density is lower than the critical density of the laser, nc∼1022 cm−3. It is heated primarily by inverse bremsstrahlung, which produces a supersonic ionization wave. In this paper, x-ray conversion efficiency and imaging from time-resolved and time-integrated diagnostics are compared over a range of experimental parameters. This work represents an important, new method for development of efficient, large-area, tailored multi-keV x-ray sources.
Probing the sulfur polymerization transition in situ with Raman spectroscopy
Authors: Kalampounias A. G. , Andrikopoulos K. S. , Yannopoulos S. N.
Published: April 2003

In this paper we demonstrate the ability of inelastic (Raman) light scattering to probe polymerization transitions. We show that after proper treatment—that is, separating isotropic and anisotropic contributions and employing the reduced representation which removes the thermal population effect of vibrational energy levels—the Raman data can be used as an accurate quantitative indicator of monomer↔polymer transitions. In particular, we have applied this method to study the thermoreversible polymerization transition of liquid sulfur up to 300 °C. Raman spectra obtained from rapidly quenched samples over a broad low-temperature range, from −180 °C to ambient temperature, revealed the fact that the equilibrium between monomers and polymers in the solid amorphous state is precarious; thus quench-and-dissolution methods employed to determine the polymer content of the liquid are not accurate. Our data are compared with existing data obtained via quench-and-dissolution techniques showing considerable dissimilarities above 250 °C. Our experimental data seem to conform better to the equilibrium polymerization transition theories than previously reported data especially in view of the lack of a high-temperature plateau value in the extent of polymerization, although complete agreement between experiments and theory is still missing. Finally, the width of the Raman peak assigned to polymeric sulfur vibrations has been used as a rough indicator of the size distribution of sulfur chains.
Lens-free heterodyne detection for transient grating experiments
Authors: Katayama K. , Yamaguchi M. , Sawada T.
Published: April 2003

An enhanced technique of heterodyne detection for transient grating experiments has been developed. This technique features a very simple optical alignment because no lenses are used to focus beams on the samples. It was applied to a vapor-deposited gold thin film (thickness: 30 nm), and the detected signal was confirmed to consist of a heterodyne component based on the dependence of the signal intensity on the pump intensity. Furthermore, this technique was shown to provide easy control of the phase difference between the probe and reference beams.
Tunable photonic crystals fabricated in III-V semiconductor slab waveguides using infiltrated liquid crystals
Authors: Schuller Ch. , Klopf F. , Reithmaier J. P. , Kamp M. , Forchel A.
Published: April 2003

Microcavity structures formed by two-dimensional photonic crystal mirrors with triangular lattice and a crystal period of 280 nm suitable for transmission experiments at about 1 μm were fabricated in III-V semiconductor planar waveguides. The photonic crystals were filled with a liquid crystal of type E7. The wavelength of the resonance peak can be shifted by the temperature-dependent refractive index of the liquid crystal. The temperature shift follows the typical refractive index behavior of liquid crystals, with a jump in wavelength at the clearing point (about 60 °C) and a continuous shift below. The wavelength jump is about 4 nm within a few Kelvin, while the total shift amounts to 9 nm between 20 and 70 °C. The experimental results agree well with the calculated temperature dependent photonic band structure by assuming a preferential alignment of the liquid-crystal molecules parallel to the holes.
Feasibility of performance measurement system for supply chain: a process‐based approach and measures
Authors: Chan Felix T.S. , Qi H.J.
Published: April 2003

Nowadays more than ever, supply chain management has gained a tremendous amount of attention from both the academic and practitioner communities. It provides a revolutionary management philosophy to cope with the increasing business competition and economy globalization. However, there exist many puzzles, especially in structure mapping and analysis, and performance measurement. The objective of this paper is to propose a process‐based approach to mapping and analyzing the practically complex supply chain network. Via this approach, a process‐based performance measurement system is proposed, in which a method called performance of activity is used to identify the performance measures and metrics.
Contribution of the dimeric state to the thermal stability of the flavoprotein D‐amino acid oxidase
Authors: Pollegioni Loredano , Iametti Stefania , Fessas Dimitrios , Caldinelli Laura , Piubelli Luciano , Barbiroli Alberto , Pilone Mirella S. , Bonomi Francesco
Published: April 2003

The flavoenzyme DAAO from Rhodotorula gracilis, a structural paradigm of the glutathione‐reductase family of flavoproteins, is a stable homodimer with a flavin adenine dinucleotide (FAD) molecule tightly bound to each 40‐kD subunit. In this work, the thermal unfolding of dimeric DAAO was compared with that of two monomeric forms of the same protein: a Δloop mutant, in which 14 residues belonging to a loop connecting strands βF5–βF6 have been deleted, and a monomer obtained by treating the native holoenzyme with 0.5 M NH4SCN. Thiocyanate specifically and reversibly affects monomer association in wild‐type DAAO by acting on hydrophobic residues and on ionic pairs between the βF5–βF6 loop of one monomer and the αI3′ and αI3″ helices of the symmetry‐related monomer. By using circular dichroism spectroscopy, protein and flavin fluorescence, activity assays, and DSC, we demonstrated that thermal unfolding involves (in order of increasing temperatures) loss of tertiary structure, followed by loss of some elements of secondary structure, and by general unfolding of the protein structure that was concomitant to FAD release. Temperature stability of wild‐type DAAO is related to the presence of a dimeric structure that affects the stability of independent structural domains. The monomeric Δloop mutant is thermodynamically less stable than dimeric wild‐type DAAO (with melting temperatures (Tms) of 48°C and 54°C, respectively). The absence of complications ensuing from association equilibria in the mutant Δloop DAAO allowed identification of two energetic domains: a low‐temperature energetic domain related to unfolding of tertiary structure, and a high‐temperature energetic domain related to loss of secondary structure elements and to flavin release.
Influence of Rub-Grooves on Labyrinth Seal Leakage
Authors: Denecke J. , Schramm V. , Kim S. , Wittig S.
Published: April 2003

An experimental investigation on the influence of stator rub-grooves on labyrinth seal leakage is presented in the present paper. In current labyrinth seal designs, abradable lands allow the rotor labyrinth teeth to rub grooves into the stator. These rub-grooves have a large influence on the seal leakage characteristic and impair the overall engine efficiency. To improve the understanding of rub-groove effects, discharge coefficients were determined using a plain nonrotating labyrinth seal model of scale 4:1 considering a wide variation of rub-groove geometries at different seal clearances. Three labyrinth seal types were covered in this investigation that are generally used in gas turbines, namely 1) straight-through labyrinth seals, 2) stepped labyrinth seals with forward facing steps, and 3) stepped labyrinth seals with backward facing steps. To attain a deeper insight into the flow mechanisms, water-channel visualizations were performed. The large data set generated in this study, provides the basis to analyze and quantify the influence of rub-grooves on the seal leakage for the three aforementioned labyrinth seal types. Current results were in agreement with previous studies on worn labyrinth seals for several seal geometries.
COMPUTATION OF THE CONTINUOUS WAVELET TRANSFORM ON MASSIVELY PARALLEL SIMD ARRAYS
Authors: FEIL MANFRED , UHL ANDREAS , VAJTERŠIC MARIAN
Published: April 2003

Strategies for computing the continuous wavelet transform on massively parallel SIMD arrays are introduced and discussed. The different approaches are theoretically assessed and the results of implementations on a MasPar MP-2 are compared.
A NOTE ON COARSE GRAINED PARALLEL INTEGER SORTING
Authors: CHAN A. , DEHNE F.
Published: April 2003

We observe that for n/p ≥ p, which is usually the case in practice, there exists a very simple, deterministic, optimal coarse grained parallel integer sorting algorithm with 24 communication rounds (6 [Formula: see text]-relations and 18 p-relations), O (n/p) memory per processor and O (n/p) local computation. Experimental data indicates that the algorithm has very good performance in practice.
PARALLEL SEARCH AND MULTISEARCH IN MATRICES WITH SORTED COLUMNS
Authors: JAIN AMIT
Published: April 2003

In this paper we consider the problem of searching, and ranking, in an m × n matrix with sorted columns on the EREW PRAM model. We propose a work-optimal parallel algorithm, based on the technique of accelerated cascading, that runs in O( lg m lg lg m)-time for small elements with rank k ≤ m and in O( lg m lg lg m lg (k/m))-time otherwise. Then we show how to improve the parallel-searching algorithm to run in O( lg m lg * lg m))-time with optimal work for small elements (with rank k ≤ m) and in O( lg m lg * ( lg m) lg (k/m))-time with optimal work for large elements (m < k ≤ mn). Next we present a sequential algorithm for multisearch in a matrix with sorted columns. Finally we present a parallel multisearch algorithm that is a generalization of the sequential multisearch algorithm and has a nontrivial dependence on the ranks of the search-elements as well as on the number of search-elements.
APPLICATION OF JAIN AND MUNCZEK'S BOUND-STATE APPROACH TO γγ-PROCESSES OF π0, ηc AND ηb
Authors: KEKEZ DALIBOR , BISTROVIĆ BOJAN , KLABUČAR DUBRAVKO
Published: April 2003

We point out the problems affecting most quark–antiquark bound-state approaches when they are faced with the electromagnetic processes dominated by Abelian axial anomaly. However, these problems are resolved in the consistently coupled Schwinger–Dyson and Bethe–Salpeter approach. Using one of the most successful variants of this approach, we find the dynamically dressed propagators of the light u and d quarks, as well as the heavy c and b quarks, and find the Bethe–Salpeter amplitudes for their bound states π0, ηc and ηb. Thanks to incorporating the dynamical chiral symmetry breaking, the pion simultaneously appears as the (pseudo)Goldstone boson. We give the theoretical predictions for the γγ decay widths of π0, ηc and ηb, and for the π0γ⋆→γ transition form factor, and compare them with experiment. In the chiral limit, the axial-anomaly result for π0→γγ is reproduced analytically in the consistently coupled Schwinger–Dyson and Bethe–Salpeter approach, provided that the quark–photon vertex is dressed consistently with the quark propagator, so that the vector Ward–Takahashi identity of QED is obeyed. On the other hand, the present approach is also capable of quantitatively describing systems of heavy quarks, concretely ηc and possibly ηb, and their γγ-decays. We discuss the reasons for the broad phenomenological success of the bound-state approach of Jain and Munczek.
ANTI-DE-SITTER SPACE, BRANES, SINGLETONS, SUPERCONFORMAL FIELD THEORIES AND ALL THAT
Authors: DUFF M. J.
Published: April 2003

There has recently been a revival of interest in anti-de-Sitter space (AdS), brought about by the conjectured duality between physics in the bulk of AdS and a conformal field theory on the boundary. Since the whole subject of branes, singletons and superconformal field theories on the AdS boundary was an active area of research about ten years ago, we begin with a historical review, including the idea of the "membrane at the end of the universe." We then compare the old and new approaches and discuss some new results on AdS 5 × S5 and AdS 3 × S3.
SEMICLASSICAL THEORY OF EXCITONIC POLARITONS IN A PLANAR SEMICONDUCTOR MICROCAVITY
Authors: XU GU , LI DINGZHOU , WANG BINGSHEN , SU ZHAO-BIN
Published: April 2003

We present a comprehensive theoretical description of quantum well exciton–polaritons imbedded in a planar semiconductor microcavity. The exact nonlacal dielectric response of the quantum well exciton is treated in detail. The 4-spinor structure of the hole subband in the quantum well is considered, including the pronounced band mixing effect. The scheme is self-contained and can be used to treat different semiclassical aspects of the microcavity properties. As an example, we analyze the "selection" rules for the exciton–cavity mode coupling for different excitons.
STATICS OF RIGID UNITS CHAIN
Authors: LIPNIACKI TOMASZ
Published: April 2003

The statics of one-dimensional rigid units chain subject to stretching force is analyzed. The potential energy of adjacent units interaction is assumed in the simple periodic form (harmonic in the small distortion limit). The position angles of subsequent units are given by the system of two iteration equations, one of them being irreversible. The derived system of equations exhibits interesting properties significantly different from those of the standard system which describes the chain in the harmonic approximation.
GENERATING CHAOS VIA A DYNAMICAL CONTROLLER
Authors: ZHONG GUO-QUN , MAN KIM F. , CHEN GUANRONG
Published: April 2003

This Letter studies the generation of chaos from a linear autonomous system by employing a dynamical nonlinear feedback controller. The system setup is quite simple, and the only nonlinearity is a piecewise-quadratic function in the form of x|x|. Both computer simulation and circuit implementation are given to verify the chaos generated by this mechanism.
CONNECTIONS ON STATISTICAL MANIFOLDS OF DENSITY OPERATORS BY GEOMETRY OF NONCOMMUTATIVE Lp-SPACES
Authors: GIBILISCO PAOLO , ISOLA TOMMASO
Published: April 2003

Let [Formula: see text] be a statistical manifold of density operators, with respect to an n.s.f. trace τ on a semifinite von Neumann algebra M. If Sp is the unit sphere of the noncommutative space Lp(M, τ), using the noncommutative Amari embedding [Formula: see text], we define a noncommutative α-bundle-connection pair (ℱα, ∇α), by the pullback technique. In the commutative case we show that it coincides with the construction of nonparametric Amari–Čentsov α-connection made in Ref. 8 by Gibilisco and Pistone.
NOISE AS A PROBE OF THE CHARGE TRANSPORT MECHANISMS THROUGH THIN OXIDES IN MOS STRUCTURES
Authors: CRUPI F. , CIOFI C. , PACE C. , IANNACCONE G. , NERI B.
Published: April 2003

In this letter, we will show that the current through the oxide in MOS structures is not always characterized by full shot noise, as it is generally assumed. We will report different noise behaviors associated to different conduction mechanisms through the oxide and we will discuss a case where the noise characterization has been used as a powerful probe of the charge transport mechanism, thus resulting in the discrimination between the several proposed models.
COMMON AND DIFFERENT FEATURES BETWEEN THE BEHAVIOR OF THE CHAOTIC DYNAMICAL SYSTEMS AND THE 1/fα-TYPE NOISE
Authors: KOLEVA MARIA K. , COVACHEV VALÉRY C.
Published: April 2003

The major goal of the present paper is to find out the manifestation of the boundedness of fluctuations. Two different subjects are considered: (i) an ergodic Markovian process associated with a new type of large scale fluctuations at spatially homogeneous reaction systems; (ii) simulated dynamical systems that possess strange attractors. Their common property is that the fluctuations are bounded. It is found out that the mathematical description of the stochasticity at both types of systems is identical. Then, it is to be expected that it exhibits certain common features whose onset is the stochasticity, namely: (i) The power spectrum of a time series of length T comprises a striclty decreasing band that uniformly fits the shape 1/fα(f) where [Formula: see text] and α(f) strictly increases to the value α(∞) = p(p > 2) as f. approaches infinity. Practically, at low frequencies this shape is 1/f-like with high accuracy because the deviations of the non-constant exponent α(f) from 1 are very small and become even smaller as the frequency tends to 1/T. The greatest advantage of the shape 1/fα(f) is that it ensures a finite variance of fluctuations. (ii) It is found out that the structure of a physical and a strange attractor is identical and they are non-homogeneous. (iii) The Kolmogorov entropy is finite.
Clinical Implications of Abnormalities of Chromosomes 1 and 13 in Multiple Myeloma
Authors: Nakagawa Yasunori , Sawanobori Masakazu , Amaya Hiroshi , Matsuda Isao , Inoue Yasuyuki , Suzuki Kenshi , Hashimoto Sachiko , Kanno Keiko
Published: April 2003

Stratification of patients with multiple myeloma according to clinical severity was attempted by chromosomal analysis of 180 bone marrow specimens from 79 patients. The 79 patients were hospitalized and treated between 1994 and 1999. Abnormalities of chromosome 1 were detected at the initial medical examination in 8 (10%) of the 79 patients and were found during follow-up in additional 3 patients. Abnormalities of chromosome 1 were often detected in IgA (4/17) and IgD (2/4) multiple myeloma, while detection in IgG myeloma was relatively rare (4/42). The relevant break points were 1q12 in 5 patients and 1q42 and 1q21 in 3 patients, while 3 patients had trisomy 1. Deficiency of the long arm of chromosome 13 was detected in 6 patients, and this was believed to imply a prognosis. The long arm was completely deleted in 2 patients and part of the arm (13q10–14) was deleted in 4 patients. It is interesting that all 6 patients had concomitant abnormalities of chromosome 1. Although the initial response to treatment of patients having abnormal chromosomes 1 and 13 was comparable to that of patients having other chromosomal abnormalities or patients who were karyotypically normal, the median survival time was only 18 months (p < 0.02). Consequently, aggressive treatment such as early stem cell transplantation and so on is needed to improve their survival.
Alternative Splicing of Cyclooxygenase-1 mRNA in the Human Iris
Authors: Dröge Melloney J. , van Sorge Adriaan A. , van Haeringen Nicolaas J. , Quax Wim J. , Zaagsma Johan
Published: April 2003

In homogenates of the human iris, the nonsteroidal anti-inflammatory drug (NSAID) S(+)flurbiprofen has been reported to inhibit cyclooxygenase-1 (COX-1) 70-fold more potently than in human whole blood. We hypothesized that this difference may be due to alternative splicing of COX-1 mRNA in the human iris or in whole blood. In this study, we have identified a similar COX-1 splice variant (COX-1SV) in both tissues with comparable COX-1/COX-1SV expression ratios. Therefore, we conclude that the difference in IC50 values of S(+)flurbiprofen towards COX-1 in the human iris and human whole blood is not related to differences in the occurrence of spliced COX-1.