bluuebunny/crossref_metadata_2025 huggingface dataset:
Acetylcholinesterase induces neuronal cell loss, astrocyte hypertrophy and behavioral deficits in mammalian hippocampus
Authors: Chacón Marcelo A. , Reyes Ariel E. , Inestrosa Nibaldo C.
Published: September 2003

Previous studies have demonstrated that acetylcholinesterase (AChE) promotes the assembly of amyloid‐β‐peptides into neurotoxic amyloid fibrils and is toxic for chick retina neuronal cultures and neuroblastoma cells. Moreover, AChE is present in senile plaques in Alzheimer's disease (AD) brains. Here we have studied the effect of AChE on astrocytes and hippocampal neurons in vivo. Morphological as well as behavioral disturbances were analyzed after intrahippocampal injection of AChE. Rats were trained in the Morris water maze and assayed for behavioral parameters. Neuronal cell loss was found in the upper leaf of the dentate gyrus in rats injected with AChE in comparison with control animals. Glial fibrillary acidic protein immunoreactivity showed astrocytic hypertrophy and the magnitude of the response was associated with neuronal cell loss. Behavioral results show that injection of AChE produces cognitive impairment demonstrated by an altered water maze performance including (i) a higher escape latency score, (ii) a decreased spatial acuity and (iii) a shorter time of swimming in the platform quadrant. These findings indicate that a local increment in neuronal AChE concentration at the mammalian hippocampus, such as those present in amyloid deposits, may play a role in triggering neuropathological and behavioral changes such as those observed in AD brains.
Fenfluramine‐induced serotonergic neurotoxicity in mice: lack of neuroprotection by inhibition/ablation of nNOS
Authors: Itzhak Yossef , Ali Syed F. , Anderson Karen L.
Published: September 2003

Previous studies have implicated a role for nitric oxide (NO) and peroxynitrite in methamphetamine‐induced dopaminergic neurotoxicity. The present study was undertaken to investigate whether NO is involved in serotonergic neurotoxicity caused by fenfluramine. In the first experiment, the effect of the neuronal nitric oxide synthase (nNOS) inhibitor 7‐nitroindazole (7‐NI; 25 mg/kg × 4) on fenfluramine (25 mg/kg × 4)‐induced serotonergic neurotoxicity in Swiss Webster mice was investigated. In the second experiment, the effect of fenfluramine (25 mg/kg × 4) on nNOS (–/–) and wild‐type (WT) mice was investigated. Fenfluramine induced hypothermia in all three mouse strains, and 7‐NI had no thermoregulatory effect. Selective depletion of 5‐HT and 5‐HT transporter binding sites in the striatum, frontal cortex and hippocampus in all three mouse strains was observed, with no evidence of dopaminergic neurotoxicity. In the first experiment, 7‐NI did not attenuate serotonergic neurotoxicity in Swiss Webster mice. In the second experiment, nNOS(–/–) and WT mice were equally sensitive to serotonergic neurotoxicity. These findings suggest that NO and peroxynitrite do not mediate fenfluramine‐induced serotonergic neurotoxicity, and that NO is a selective mediator of amphetamines‐induced dopaminergic neurotoxicity.
A rivulet of perfectly wetting fluid with temperature-dependent viscosity draining down a uniformly heated or cooled slowly varying substrate
Authors: Duffy B. R. , Wilson S. K.
Published: September 2003

We use the lubrication approximation to analyze the steady locally unidirectional gravity-driven draining of a thin rivulet of a perfectly wetting Newtonian fluid with temperature-dependent viscosity down a slowly varying substrate that is either uniformly hotter or uniformly colder than the surrounding atmosphere, and hence highlight the similarities and differences between the perfectly wetting and the nonperfectly wetting cases.
Computational study of a weakly compressible mixing barrier in low Prandtl number, strongly stratified fluids
Authors: McLaughlin Richard M. , Zhou Hong , Forest M. Gregory
Published: September 2003

The effects of weak compressibility in the evolution of a fluid governed by the anelastic fluid equations are explored computationally. The basis for this study is a careful determination of the role which the anelastic divergence constraint plays in the evolution of a periodic array of interacting vortices. Our numerical studies address a blocking phenomenon occurring in strongly stratified flows with small Prandtl numbers. Computationally, we first document this blocking event which strongly limits vertical mixing. This is achieved using idealized equations of fluid motion which do not excite a density perturbation and exhibits that the presence of a strong density transition layer, consistently modeled in the anelastic mass balance, may lead to a dramatic modification of vortex interactions when compared with the incompressible analog. These modifications are evidenced by the formation of a weakly compressible mixing barrier. We subsequently isolate this particular blocking phenomenon as emerging in the limit of small Prandtl number through a sequence of computational simulations of the complete anelastic fluid equations which retain a density perturbation. It is shown that a sequential reduction of the Prandtl number yields much weaker vertical mixing as evidenced by passive tracer statistics.
A gas phase displacing a liquid with soluble surfactants out of a small conduit: The plane case
Authors: Severino Marcelo , Giavedoni Marı́a D. , Saita Fernando A.
Published: September 2003

In this work we report the actions of soluble surfactants when a liquid contained between parallel plates is being displaced by a steadily moving gas phase. For that purpose the full Navier–Stokes equations are solved together with surfactant mass balances at the interface, as well as in the liquid phase. The influence of the different relevant dimensionless parameters is described and analyzed for capillary numbers within the range 10−4–1; these results proved to be in good agreement with those obtained by Ratulowski and Chang for very low values of the capillary number. Besides, the bulk and interfacial distribution of surfactants along with the corresponding flow fields are shown for several values of the elasticity and Péclet numbers.
Direct numerical simulations of free convection beneath an air–water interface at low Rayleigh numbers
Authors: Leighton R. I. , Smith G. B. , Handler R. A.
Published: September 2003

Direct numerical simulations of a cooling air–water interface were employed to determine the structure of the temperature, velocity, and vorticity fields in the thin thermal boundary layer formed at the free surface. The simulations were performed at low to moderate Rayleigh numbers. In this flow, the turbulence is initiated by the Rayleigh instability at the interface and is maintained by buoyant production. Visualizations of the flow reveal that the temperature field at the interface is composed of large warm patches surrounded by cooler dense fluid which accumulates in thin bands. The cool fluid associated with the bands initially falls in sheets, but rapidly forms descending tubes and plumes. The turbulence statistics were scaled both with outer and inner variables. The latter scaling is based on the so-called surface strain model which is essentially consistent with Townsend’s inner scaling. It is found that the temperature statistics collapse well using inner variables. On the other hand, the vertical velocity scales well with inner variables within the thermal boundary layer, but at greater depths it becomes more appropriate to use outer scaling. The anisotropic nature of the velocity statistics in the core of the flow is ascribed to the relatively low Rayleigh numbers used in the simulations. An explanation for this anisotropy is offered based on a detailed examination of the turbulence kinetic energy balances.
A priori testing of wall models for separated flows
Authors: Kaltenbach Hans-Jakob
Published: September 2003

Databases from numerical simulation of wall-bounded flows with closed reverse flow regions were examined in order to derive models, which relate the mean wall shear stress to flow quantities in a certain distance from the wall. The approach makes use of the particular shape of the profiles of turbulent shear stress which balances the streamwise pressure gradient outside the viscosity-affected near-wall region. One model version requires as input the streamwise pressure gradient and a velocity scale UW which results from linear extrapolation of the mean flow to the wall. Its application is restricted to the part of the reverse flow region with nonvanishing adverse pressure gradient. A more general applicable skin-friction law is derived from the observation that near-wall mean velocity profiles approximately collapse if they are scaled in a defect form. This scaling holds up to approximately half a bubble length downstream of attachment. Numerical values for model coefficients vary slightly from flow to flow and seem to depend on the Reynolds number.
On the displacement of fluid bridges from solid surfaces in viscous pressure-driven flows
Authors: Dimitrakopoulos P. , Higdon J. J. L.
Published: September 2003

The yield conditions for the displacement of three-dimensional fluid bridges from solid boundaries are studied in pressure-driven Stokes flows. The study seeks the optimal shape of the contact line that yields the maximum flow rate for which a fluid bridge can adhere to the surfaces. The contact line contours show fore-and-aft asymmetry with a distorted shape not well represented by simple circular/elliptical planforms. The critical shear rate is shown to be sensitive to viscosity ratio; as the viscosity of the bridge increases, the critical shear rate decreases facilitating the displacement. The effects of the contact angles are found to be similar for both viscous and inviscid bridges, in direct contrast with our earlier results for drop displacement from a single substrate. The critical flow rate is strongly affected by the plate spacing; bridges with moderate height are shown to withstand the highest flow rate. This behavior is readily explained employing scaling analysis.
Magnetic properties of heavily Mn-doped quaternary alloy ferromagnetic semiconductor (InGaMn)As grown on InP
Authors: Ohya Shinobu , Kobayashi Hideo , Tanaka Masaaki
Published: September 2003

We have studied magnetic properties of heavily Mn-doped [(In0.44Ga0.56)0.79Mn0.21]As thin films grown by low-temperature molecular-beam epitaxy on InP substrates. (InGaMn)As with high Mn content (21%) was obtained by decreasing the growth temperature to 190 °C. When the thickness of the [(In0.44Ga0.56)0.79Mn0.21]As layer is equal or thinner than 10 nm, the reflection high-energy electron diffraction pattern and transmission electron microscopy show no MnAs clustering, indicating that a homogeneous single crystal was grown. Magnetic circular dicroism characterizations, as well as transport and magnetization measurements, indicate that the Curie temperature is 125–130 K.
Probing carriers in two-dimensional systems with high spatial resolution by scanning spreading resistance microscopy
Authors: Maknys K. , Douhéret O. , Anand S.
Published: September 2003

In this work, cross-sectional scanning spreading resistance microscopy (SSRM) is used to profile carriers in quantum wells (QWs). The investigated structures consist of InGaAs wells of different widths sandwiched between Si-doped InP barriers. It is demonstrated that SSRM is indeed capable of detecting electrons in the quantum wells with high lateral resolution and that the SSRM signal shows a systematic trend for the different wells. Clear dips in the resistance signal are observed at the quantum wells and imply accumulated electron densities higher than in the surrounding barriers. Carrier density in the QW is found by using the calibration curve obtained from the resistance measurements on reference layers sample. It is also shown that only at certain appropriate tip-sample bias conditions the depletion regions in the barriers adjacent to the wells are resolved. Finally, we demonstrate that under very low forward biases the full width at half maximum of the observed resistance dips in SSRM data is nearly equal to the geometric QW widths.
Microchemistry and magnetization reversal mechanism in melt-spun 2:17-type Sm-Co magnets
Authors: Yan A. , Gutfleisch O. , Gemming T. , Müller K.-H.
Published: September 2003

The stability of microstructure and of microchemistry in melt-spun precipitation-hardened Sm(Co,Fe,Cu,Zr)z magnets at high temperature and its effect on the magnetic properties, especially the coercivity at room temperature, were investigated by transmission electron microscopy, nanoprobe chemical analysis, and magnetic measurements. A very large gradient of the Cu content within the 1:5-type cell boundary phase was observed in highly coercive melt-spun Sm(Co,Fe,Cu,Zr)z magnets with uniform cellular structure. After an additional isothermal aging at 850 °C for 5 min, the coercivity is reduced dramatically from 3 T to 0.16 T. This is accompanied by the disappearance of the large gradient of Cu content within the cell boundary phase. Thus, it is proposed that the high coercivity in 2:17 Sm-Co magnets originates from the large gradient of domain wall energy within the Sm(Co,Cu)5 cell boundary phase. This gradient is caused by a very rapid phase separation taking place within the cell boundary phase during slow cooling.
Stagnant Layer Conduction in Surfactant-Stabilized Hexadecane Emulsion Systems Measured by Electroacoustics
Authors: Djerdjev Alex M. , Beattie James K. , Hunter Robert J.
Published: September 2003

Previously reported zeta-potentials calculated from the electroacoustic behaviour of sodium dodecyl sulfate (SDS) stabilized hexadecane emulsion droplets show certain anomalies. These can be resolved when electrical conduction in the stagnant layer behind the shear plane is included in the analysis. If stagnant layer conduction is ignored the addition of salt causes the apparent droplet size to increase and the magnitude of the zeta-potential to show a maximum. When stagnant layer conduction is included the dynamic mobility spectra can be fitted to a constant size distribution independent of the salt concentration with zeta-potentials that decrease as expected with increasing electrolyte concentration. Increasing SDS concentration, before the homogenization process, causes a decrease in droplet size and an increase in the total surface conductance to a constant value corresponding to the saturation of the surface with SDS. It is shown that the surface conductance and particle size distribution of hexadecane at any given volume fraction are functions of the concentration of SDS and the oil volume fraction. The zeta-potential changes log-linearly with added electrolyte and is independent of the SDS concentration or oil volume fraction used during the emulsification process.
Preparation and Catalysis of Inverted Core/Shell Structured Pd/Au Bimetallic Nanoparticles
Authors: Shiraishi Yukihide , Ikenaga Daisuke , Toshima Naoki
Published: September 2003

Reduction of two different precious metal ions by refluxing in ethanol/water in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) gave a colloidal dispersion of core/shell structured bimetallic nanoparticles. In the case of Pd and Au ions, for example, the colloidal dispersions of bimetallic nanoparticles with a Au core/Pd shell structure are produced. In contrast, it is difficult to synthesize bimetallic nanoparticles with the inverted core/shell (in this case, Pd core/Au shell) structure. Here the sacrificial hydrogen strategy has been used to construct the inverted core/shell structure, where the colloidal dispersions of Pd cores are treated with hydrogen and then the solution of the second element, Au ions, is slowly added to the dispersions. This novel method, developed by us, gave the inverted core/shell structured bimetallic nanoparticles. The Pd core/Au shell structure has been confirmed by FT-IR spectra of adsorbed carbon monoxide. The hydrogenation of methyl acrylate catalyzed by the nanoparticles before and after heat treatment was investigated as well.
Sonochemical Degradation of Sodium Dodecylbenzene Sulfonate in Aqueous Solutions
Authors: Ashokkumar Muthupandian , Niblett Tyson , Tantiongco Lyndon , Grieser Franz
Published: September 2003

The sonochemical degradation of sodium dodecylbenzene sulfonate (SDBS) has been studied over a wide concentration range spanning the critical micelle concentration (CMC) of the surfactant. The rate of degradation of SDBS increased linearly with increasing concentration below the CMC of SDBS. Above the CMC, the degradation rate continued to increase but at a much slower rate compared with that below the CMC. It was found that the increasing rate of degradation of SDBS correlated closely with the decrease in the air/water surface tension of the surfactant solutions. The results of this study strongly suggest that the initial step in the degradation process is OH• radical attack onto SDBS molecules adsorbed at the cavitation bubble/solution interface. The sonication of SDBS solutions for extended periods of time (ca. 12 h) led to the generation of gaseous hydrocarbon products, such as methane, ethane, ethylene, and acetylene. It is concluded that further radical attack occurs on the intermediates produced from the initial degradation step. This further degradation pathway is responsible for producing both water-soluble species, and volatile products that are pyrolyzed within the cavitation bubbles.
Effects of pruning a temperate mangrove forest on the associated assemblages of macroinvertebrates
Authors: Gladstone William , Schreider Maria J.
Published: September 2003

Mangrove forests around the world are being impacted by development in adjacent land and water areas. An after-control-impact study was undertaken to assess the effects of mangrove forest pruning on the associated benthic macroinvertebrate fauna. Pruning, undertaken 5 years before our sampling period, reduced the height of the forest canopy from 5 m to 1 m. Macrobenthic assemblages were sampled in September 2000 and January 2001 from two randomly selected sites within the pruned section of forest, and two sites in each of two control locations in the same forest. Assemblage composition in the pruned and undisturbed mangrove forests was not significantly different, nor were there significant differences in variability between the two areas. Similarity matrices for assemblages based on higher taxonomic groups and molluscs were highly correlated with similarity matrices for all taxa, indicating the utility of more rapid forms of assessment in this habitat. The results suggest that although short-term impacts may have occurred, no impact on macroinvertebrate assemblages was evident 5 years after the pruning.
Strengthening farmers' capacities for plant genetic resources conservation in Mali
Authors: Huvio Tiina , Sidibé Amadou
Published: September 2003

Farmers in local communities have a considerable amount of information on their genetic resources both at the individual and community level. The farmers' knowledge is interweaved into their daily practices as a reserve accumulated over the generations. The Farmer Field Fora approach (FFF) has been conceptualized in order to activate farmers to identify the existing resources both in the crops they cultivate and in their knowledge, to recognize its value and to start using it more consciously. The FFF approach links the use of existing diversity to the possibility of having new varieties and to improving productivity. In weekly meetings farmers observe changes in the field between varieties, debate on them and draw conclusions. In every session a theme on plant development is debated among farmers with the aid of a facilitator. Close contact with researchers allows involvement with the breeding practices and enables the aims and conduct used in research to be understood. This empowers farmers to participate in a more active way in research, to apply more precise ways of observing and managing their genetic resources, and to link their work to conservation activities at the national and local level. The results of the FFF trial, which was carried out in 10 villages in the region of San in Mali in 2001, show an increased interest among farmers to observe varieties. The appreciation criteria used is multiple including yield, earliness, strong tillers, high number of tillers, and resistance for diseases and Striga. It seems obvious that even though the goal of the approach is on-farm conservation of plant genetic resources, it must be closely linked to farmers' interest. The variation of the results between villages demonstrates variability of climatic condition in this region and a high genotype—environment interaction. Further modifications of the approach are required in order to improve equitable participation of different stakeholders and improve the institutionalization of on-farm conservation.
Auxin Up-Regulates MtSERK1 Expression in Both Medicago truncatula Root-Forming and Embryogenic Cultures
Authors: Nolan Kim E. , Irwanto Rina R. , Rose Ray J.
Published: September 2003

We have cloned a SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) gene from Medicago truncatula (MtSERK1) and examined its expression in culture using real time PCR. In the presence of the auxin 1-naphthaleneacetic acid (NAA) alone, root differentiation occurs from the proliferating calli in both the cultured highly embryogenic seed line (2HA) and a low to nonembryogenic seed line (M. truncatula cv Jemalong). Auxin stimulated MtSERK1 expression in both 2HA and M. truncatula cv Jemalong. Embryo induction in proliferating calli requires a cytokinin in M. truncatula and unlike root formation is substantively induced in 2HA, not M. truncatula cv Jemalong. On embryo induction medium containing NAA and the cytokinin 6-benzylaminopurine (BAP), expression of MtSERK1 is elevated within 2 d of initiation of culture in both M. truncatula cv Jemalong and 2HA. However, MtSERK1 expression is much higher when both NAA and BAP are in the medium. BAP potentiates the NAA induction because MtSERK1 expression is not up-regulated by BAP alone. The 2HA genotype is able to increase its embryo formation because of the way it responds to cytokinin, but not because of the cytokinin effect on MtSERK1. Although the studies with M. truncatula indicate that somatic embryogenesis is associated with high SERK expression, auxin alone does not induce somatic embryogenesis as in carrot (Daucus carota) and Arabidopsis. Auxin in M. truncatula induces roots, and there is a clear up-regulation of MtSERK1. Although our analyses suggest that MtSERK1 is orthologous to AtSERK1, which in Arabidopsis is involved in somatic embryogenesis, in legumes, MtSERK1 may have a broader role in morphogenesis in cultured tissue rather than being specific to somatic embryogenesis.
Adoption of ICT and e‐commerce in small businesses: an HEI‐based consultancy perspective
Authors: Matlay Harry , Addis Mark
Published: September 2003

This article sets out to critically evaluate the impact that higher education institution (HEI)‐based consultancy can have upon the adoption and use of e‐commerce by businesses units operating in the small business sector of the British economy. Anecdotal evidence suggests that “new” (post‐1992) universities are more likely to offer consultancy services to small businesses. It is also claimed that owner/managers seem reluctant to pay full economic prices and would only subscribe to HEI‐based consultancy services if and when these are supported by considerable subsidies. In order to test the owner/manager reluctance hypothesis, 60 matched case studies were conducted, involving small businesses based in the West Midlands region of Great Britain. Preliminary results indicate that most small business owner/managers are aware of the potential benefits accruing from ICT and e‐commerce and tend to use HEI‐based consultancy services as a subsidised access point to e‐markets, involving both their core and peripheral activities. There exists, however, an apparent mismatch between the supply and demand sides of the HEI‐based ICT and e‐commerce consultancy market.
Benchmark Calculations in Risk Assessment Using Continuous Dose‐Response Information: The Influence of Variance and the Determination of a Cut‐Off Value
Authors: Sand Salomon J. , Von Rosen Dietrich , Filipsson Agneta Falk
Published: September 2003

A benchmark dose (BMD) is the dose of a chemical that corresponds to a predetermined increase in the response (the benchmark response, BMR) of a health effect. In this article, a method (the hybrid approach) for benchmark calculations from continuous dose‐response information is investigated. In the formulation of the methodology, a cut‐off value for an adverse health effect has to be determined. It is shown that the influence of variance on the hybrid model depends on the choice of determination of the cut‐off point. If the cut‐off value is determined as corresponding to a specified tail proportion of the control distribution, P(0), the BMD becomes biased upward when the variance is biased upward. On the contrary, if the cut‐off value is directly determined to some level of the continuous response variable, the BMD becomes biased upward when the variance is biased downward. A simulation study was also performed in which the accuracy and precision of the BMD was compared for the two ways of determining the cut‐off value. In general, considering BMRs of 1, 5, and 10% (additional risk) the precision of the BMD became higher when the cut‐off value was estimated by specifying P(0), relative to the case with a direct determination. Use of the square‐root of the maximum‐likelihood estimator of the variance in BMD estimation may provide a bias that is reflected by the cut‐off formulation (downward bias if specifying P(0), and upward bias if specifying the cut‐off, c, directly). This feature may be reduced if an unbiased estimator of the standard deviation is used in the calculations.
The Krüger problem and neutron spin games
Authors: Ignatovich Vladimir K. , Ignatovich Filipp V.
Published: September 2003

We present a compact solution to the one-dimensional problem of neutron scattering from two mutually perpendicular magnetic fields: permanent and rotating ones. Both fields are confined inside a layer of matter or a layer of a free space. The applications of this solution to the interpretation of some experiments with polarized neutrons are considered.
Visualizing the mass and width spectrum of unstable particles
Authors: Harshman N. L.
Published: September 2003

Unstable particles are characterized by their mass and mass uncertainty, in addition to other kinematic and internal parameters. The mass uncertainty is called the width of the unstable particle and can be theoretically related to the particle lifetime by the Weisskopf–Wigner relation. Several graphical representations of the mass and width spectrum of unstable subatomic particles are presented. Such plots are useful tools for introducing students to the particle zoo and provide students an alternate way to organize conceptually what can seem like an overwhelming amount of data. In particular, such graphs highlight phenomenological features of unstable particles characteristic of different energy and time scales.
3,3'-Dipyrrolyl sulfides, useful building blocks for the syntheses of macrocycles containing dipyrromethene units
Authors: Chen Qingqi , Dolphin David
Published: September 2003

5,5'-Dicarboxy-3,3'-dipyrrolyl sulfide was condensed with 5,5'-diformyl-3,3'-dipyrrolyl sulfide or 5,5'-diformyldipyrromethane under acidic conditions to produce, in high yields, macrocycles containing four dipyrromethene units. Key words: 3,3-dipyrrolyl sulfide, cyclopolypyrrole, dipyrromethene, macrocycle.
Contrast-Enhanced Cranial Computed Tomography in Magnetic Resonance Imaging Era
Authors: Chishti Fayaz A. , Al Saeed Osama M. , Al-Khawari Hana , Shaikh Mehraj
Published: September 2003

Objective: To evaluate the usefulness of intravenous contrast administration in cranial computed tomography (CT) in a general hospital with a magnetic resonance imaging (MRI) facility, and to establish a protocol to determine which patients would benefit most from using contrast-enhanced cranial CT. Subjects and Methods: Five hundred and forty-seven patients who underwent routine nonenhanced CT (NECT) and contrast-enhanced CT (CECT) of the brain between June 1997 and June 2001 were divided into three groups. Group A: 496 patients in whom CECT was done in spite of normal NECT; group B: 16 patients in whom CECT was considered necessary irrespective of NECT findings, and group C: 35 patients in whom NECT was abnormal and CECT was performed. Results: Contrast-enhanced cranial CT changed and/or confirmed the diagnosis in 1 of 496 in group A, 2 of 16 in group B, and 12 of 35 in group C, thereby indicating that CECT was useful in the diagnosis of groups B and C. Conclusion: CECT is unlikely to be useful in patients with normal NECT in the appropriate clinical setting. A protocol is presented for the use of contrast media in cranial CT in a general hospital with an MRI facility. Using this protocol only 9.7% of patients for cranial CT would have needed CECT, resulting in considerable cost savings without affecting the quality of the service to the patient in a general hospital.
Orthotopic Heart Transplantation for Congenital Heart Disease: An Alternative for High-Risk Fontan Candidates?
Authors: Michielon Guido , Parisi Francesco , Squitieri Cosimo , Carotti Adriano , Gagliardi Giulia , Pasquini Luciano , Di Donato Roberto M.
Published: September 2003

Objective—

Evaluation of incremental risk factors for early mortality in children undergoing orthotopic heart transplantation (OHT) for congenital heart disease.

Methods—

Between 1988 and 2002, 43 patients (mean age 9.1±7.2 years) underwent 44 OHT for complex TGA (6), DORV (4), single ventricle (21), and other end-stage structural heart disease (11). Two discernible ventricular chambers were present in 18 pts (41.8%). Previous reconstructive or palliative procedures had been previously accomplished in 35 pts (83.3%), including atrial switch (5), systemic-to-pulmonary shunts (10), cavopulmonary anastomosis (9), Fontan completion (6), and others (5).

Results—

30-day survival for the 2-ventricle subgroup was 94.4±5.4% compared with 67.2±9.5% for the single ventricle subgroup (
P
=0.04) (overall 78.6%±3.3%). OHT following single ventricle staging to bi-directional cavopulmonary anastomosis exhibited 100% early survival, as opposed to 62.5±17.1% for OHT after systemic-to-pulmonary shunts, and 33.3±19.2% for OHT following failing Fontan (
P
=0.010). HLHS diagnosis (0.0085) and failing Fontan (
P
=0.003) were identified as independent predictors of early mortality by regression logistic modeling, while Fontan stage represented the only predictor of overall mortality by Cox proportional hazard. Overall 10-year survival was 54.3±11%.

Conclusions—

OHT for structural congenital heart disease with single ventricle physiology entails substantial early mortality and bi-directional cavopulmonary anastomosis enables the best transition to heart transplant. OHT should be considered in the decision making process as an alternative to Fontan completion in high-risk candidates, since rescue-OHT after failing Fontan seems unwarranted.
Differential cellular localization among mitotic cyclins fromSaccharomyces cerevisiae: a new role for the axial budding protein Bud3 in targeting Clb2 to the mother-bud neck
Authors: Bailly Eric , Cabantous Sandrine , Sondaz Delphine , Bernadac Alain , Simon Marie-Noëlle
Published: September 2003

The mitotic cyclin Clb2 plays a major role in promoting M-phase in budding yeast, despite its functional redundancy with three closely related cyclins Clb1, Clb3 and Clb4. Here, we further investigate the mechanisms controlling the cellular distribution of Clb2 in living cells. In agreement with observations recently made by Hood et al. [Hood, J. K., Hwang, W. W. and Silver, P. A. (2001) J. Cell Sci. 114, 589-597], we find that GFP-tagged Clb2 expressed from its natural promoter localizes to various cellular compartments, including the nucleus, the mitotic spindle, the spindle pole bodies as well as the mother-bud neck. The neck localization is specific to Clb2 as Clb1, Clb3 and Clb4 are never observed there, even when over-expressed. Mutational analysis identifies a central region of Clb2, comprising residues 213-255 and a phylogenetically conserved hydrophobic patch, as an essential cis-acting determinant. Clb2 co-localizes with the bud site selection protein Bud3. Consistent with a role of Bud3 in targeting Clb2 to the bud neck, we report a two-hybrid interaction between these proteins. Furthermore, Clb2 is shown to be specifically delocalized in Δbud3 cells and in a bud3 mutant deleted for its C-terminal Clb2-interacting domain (bud3Δ1221), but not in a Δbud10 mutant. Correlating with this phenotype, bud3Δ1221 cells exhibit a pronounced (15-30 minutes) delay in cytokinesis and/or cell separation, suggesting an unanticipated function of Clb2 in these late mitotic events. Taken together, our data uncover a new role for Bud3 in cytokinesis that correlates with its capacity to target Clb2 at the neck, independently of its well established cell-type-specific function in bud site selection.
Characterisation of PGs1, a subunit of a protein complex co-purifying with tubulin polyglutamylase
Authors: Regnard Catherine , Fesquet Didier , Janke Carsten , Boucher Dominique , Desbruyères Elisabeth , Koulakoff Annette , Insina Christine , Travo Pierre , Eddé Bernard
Published: September 2003

Polyglutamylation is a post-translational modification initially discovered on tubulin. It has been implicated in multiple microtubule functions, including neuronal differentiation, axonemal beating and stability of the centrioles, and shown to modulate the interaction between tubulin and microtubule associated proteins. The enzymes catalysing this modification are not yet known. Starting with a partially purified fraction of mouse brain tubulin polyglutamylase, monoclonal antibodies were raised and used to further purify the enzyme by immunoprecipitation. The purified enzyme complex (Mr 360×103) displayed at least three major polypeptides of 32, 50 and 80×103, present in stochiometric amounts. We show that the 32×103 subunit is encoded by the mouse gene GTRGEO22, the mutation of which has recently been implicated in multiple defects in mice, including male sterility. We demonstrate that this subunit, called PGs1, has no catalytic activity on its own, but is implicated in the localisation of the enzyme at major sites of polyglutamylation, i.e. neurones, axonemes and centrioles.
Perturbation growth in terms of barotropic alignment properties
Authors: Riviéere G. , Hua B. L. , Klein P.
Published: September 2003

In order to study the error growth due to initial uncertainties in the model state, this paper examines the alignment dynamics of the perturbation velocity vector in quasi‐geostrophic flows. In a barotropic context, the time evolution of the perturbation velocity field is the sum of two terms: (i) the stretching of the perturbation velocity vector by the basic‐state velocity‐gradient tensor (denoted ∇u) and (ii) the perturbation ageostrophic pressure gradient, which also depends on ∇u. Different analytical results show that such a system has two types of preferred orientation that induce kinetic‐energy growth: one orientation concerns one eigenvector of ∇u, the other one is linked to a fixed point of the orientation equation of the perturbation velocity vector written in strain coordinates. This analytical diagnostic is confirmed by using Monte‐Carlo techniques in a quasi‐geostrophic oceanic‐basin model of a stratified wind‐driven double‐gyre circulation, and these orientations are shown to be the most probable. These preferred orientations are of great importance for diagnosing the most probable kinetic‐energy generation rate at each grid point. An interesting outcome is that the kinetic‐energy error field is localized in regions where the norm of ∇u is large. Copyright © 2003 Royal Meteorological Society
Exploring the intragroup conflict constructs and behaviors of African American public school children in an inner‐city conflict resolution education (CRE) program
Authors: Scott K. Michelle
Published: September 2003

The Consortium on Negotiation and Conflict Resolution's (CNCR) Conflict Resolution in Schools Program (CRiSP) conducted
a two‐year study of inner‐city African American public school children to discern any conflict constructs and behaviors that were
apparent in the children's intragroup interactions. This article presents findings of the CNCR study, including three emergent
themes—fears of victimization, identity conflict, and core values—that were consistently apparent in the children's demonstrations
of intragroup conflict constructs and behaviors.
Effect of coupling resistors on steady patterns in coupled oscillator networks
Authors: Moro Seiichiro , Matsumoto Tadashi
Published: September 2003

The present authors recently reported synchronization phenomena in a star connection of several oscillators with identical characteristics through resistors. In such a system there occurs synchronization of the oscillators with deviated phases. Hence, extremely many phase conditions can be observed. The authors have also proposed a coupled oscillator network by extending this system. In the present network, many different phase patterns are observed. Based on its configuration, this network is a candidate for application as a cellular neural network (CNN). When this network is applied as a CNN, control parameters that characterize the behavior of the network are needed. In the present paper, the coupling resistors are recognized as such parameters. This paper examines how the variations of the coupling resistors affect the relationship between the initial state and the observed steady‐state pattern. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(1): 29–37, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10102
Parametric estimation of higher‐order spectra by tensor product expansion with coordinate transformation
Authors: Nishiguchi Yoshitomo , Toda Naohiro , Usui Shiro
Published: September 2003

When the characteristics of non‐Gaussian time series, such as biological signals, are described, higher‐order spectra such as the bispectrum must be referenced in addition to the power spectrum. To obtain estimates having few statistical fluctuations, parametric estimation methods of these spectra should be established. In recent years, a simple discretization method (SDM) has been proposed as a numerical solution based on iterated integral transform of the stationary joint density probability function and the higher‐order spectra of nonlinear autoregressive models like a neural network autoregressive model. However, the SDM requires an amount of calculation memory that increases exponentially with respect to the lag order of corresponding models. In order to overcome this drawback, the tensor product expansion method (TPEM) where the joint probability density function is expanded as the sum of single‐variable functions was proposed. This method can suppress the increase in the required memory capacity to a linear increase. A numerical example has shown where the TPEM calculated the bispectrum more accurately than the SDM with an equivalent amount of memory. However, the relationship between the performance of tensor product expansion and the dependence properties of the target time series has not as yet been investigated. In this paper, we study the property dependence of the time series in the TPEM and point out the problem of worsening calculation accuracy for a time series in which values at each time instant highly depend on each other. As the solution, we propose a new method that introduces a linear coordinate transform in state space where the joint probability density function undergoes the tensor product expansion. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(1): 19–28, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10103
Structural impedance based damage diagnosis by piezo‐transducers
Authors: Bhalla Suresh , Kiong Soh Chee
Published: September 2003

Although structural mechanical impedance is a direct representation of the structural parameters, its measurement is difficult at high frequencies owing to practical considerations. This paper presents a new method of damage diagnosis by means of changes in the structural mechanical impedance at high frequencies. The mechanical impedance is extracted from the electro‐mechanical admittance signatures of piezoelectric‐ceramic (PZT) patches surface bonded to the structure using the electro‐mechanical impedance (EMI) technique. The main feature of the newly developed approach is that both the real as well as the imaginary component of the admittance signature is used in damage quantification. A complex damage metric is proposed to quantify damage parametrically based on the extracted structural parameters, i.e. the equivalent single degree of freedom (SDOF) stiffness, the mass, and the damping associated with the drive point of the PZT patch. The proposed scheme eliminates the need for anya prioriinformation about the phenomenological nature of the structure or any ‘model’ of the structural system. As proof of concept, the paper reports a damage diagnosis study conducted on a model reinforced concrete (RC) frame subjected to base vibrations on a shaking table. The proposed methodology was found to perform better than the existing damage quantification approaches, i.e. the low‐frequency vibration methods as well as the traditional raw‐signature based damage quantification in the EMI technique. Copyright © 2003 John Wiley & Sons, Ltd.
Issues and challenges in strategic repositioning: the case of Cable and Wireless
Authors: Turner Colin
Published: September 2003

Between 1999 and 2002, Cable and Wireless (C&W) undertook a radical strategic repositioning as it sought to become more focused on key growth markets. Due to a combination of a declining external environment and an inadequate external environment, this process of strategic change failed to establish the company as an Internet powerhouse.

This article examines the strategic repositioning undertaken by Cable and Wireless throughout the period 1999 to 2002. It scrutinizes how the company has sought to transform itself from an integrated communications provider, covering many segments in many different locations, into a more focused operator targeting a specific commercial segment.

The major problems that the company encountered in this process of change are examined, notably in terms of the limit to strategies based on the perceived benefits of strategic focus. It concludes with an examination of what lessons can be learnt from its experience of strategic change.

Copyright © 2003 John Wiley & Sons, Ltd.
Divided by a common business? Franchisor and franchisee relationships in the pub sector
Authors: Lashley Conrad , Rowson Bill
Published: September 2003

The relationship between franchisee and franchisor can be described as being based on a number of dynamic tensions that are clearly illustrated in the relationship between pub operating companies and their tenants and lessees. The differences in business objectives, control and support together with variations in power are common to all franchise relationships.

In the pub sector tensions are further intensified when the operating companies are constrained by legal and economic pressures. Short‐term concerns often result in tenants and lessees being located in pub properties that are not suited to their circumstances, resource and needs.

Selection and recruitment of tenants and lessees is often driven by the need to secure a rent‐paying tenant or lessee into a property. A consequence of this approach is that there is a high turnover of tenants and lessees that can add considerably to operating costs. In addition, many of the companies in this research were not providing their tenants and lessees with the levels of advice and support that might help the smaller firms overcome their resource disadvantage.

This paper argues that as the pub companies move increasingly towards high volume retail orientations they will need to examine some of the more formal franchise arrangements. These arrangements would involve much more careful scrutiny of potential tenants and lessees together with more centrally defined operating systems and closer support from business advisors.

Copyright © 2003 John Wiley & Sons, Ltd.
Evaluating European Union structural funding programmes for tourism SMEs: a case from industrial South Wales
Authors: O'Sullivan D. , Stewart E. J. , Thomas B. , Sparkes A. , Young J.
Published: September 2003

This paper considers the evaluation of a programme designed to improve the contribution of tourism to the economy of industrial South Wales. The evaluation of the Network of Excellence for Action in Tourism (NEAT) initiative is compared with recent thinking around two key areas of research into tourism and economic regeneration. First, is the need for alternative (non‐traditional) approaches to evaluation, and second, is the need for effective networks of communication between tourism employers to facilitate the effective demand for skills. This paper analyses the claim that tourism development programmes offer significant advantages other than those commonly identified by funding specifications. Copyright © 2003 John Wiley & Sons, Ltd.
A dynamic multicast routing satisfying multiple QoS constraints
Authors: Chakraborty Debasish , Chakraborty Goutam , Shiratori Norio
Published: September 2003

In this paper we propose a QoS‐based routing algorithm for dynamic multicasting. The complexity of the problem can be reduced to a simple shortest path problem by applying a Weighted Fair Queuing (WFQ) service discipline. Using a modified Bellman–Ford algorithm, the proposed routing builds a multicast tree, where a node is added to the existing multicast tree without re‐routing and satisfying QoS constraints. With user defined life‐time of connection this heuristic algorthm builds multicast tree which is near optimum over the whole duration of session. Simulation results show that tree costs are nearly as good as other dynamic multicast routings that does not consider QoS. Copyright © 2003 John Wiley & Sons, Ltd.
Three‐dimensional BEM for scattering of elastic waves in general anisotropic media
Authors: Niu Yuqing , Dravinski Marijan
Published: September 2003

Based on the full‐space Green's functions, a three‐dimensional time‐harmonic boundary element method is presented for the scattering of elastic waves in a triclinic full space. The boundary integral equations for incident, scattered and total wave fields are given. An efficient numerical method is proposed to calculate the free terms for any geometry. The discretization of the boundary integral equation is achieved by using a linear triangular element. Applications are discussed for scattering of elastic waves by a spherical cavity in a 3D triclinic medium. The method has been tested by comparing the numerical results with the existing analytical solutions for an isotropic problem. The results show that, in addition to the frequency of the incident waves, the scattered waves strongly depend on the anisotropy of the media. Copyright © 2003 John Wiley & Sons, Ltd.
Elastodynamic guided wave scattering in infinite plates
Authors: Galán José M. , Abascal Ramón
Published: September 2003

The scattering of elastic guided waves by defects in two‐dimensional infinite plates is analysed in the plane and antiplane cases, corresponding, respectively, to Lamb and SH modes. A hybrid boundary element–finite element technique is used, where the defect neighbourhood is discretized with quadratic boundary elements and the radiation condition in the plate is satisfied through a normal mode expansion. A semi‐analytical finite element technique is applied in the infinite plate to calculate its dispersion curves and normal modes. This hybrid technique, which showed excellent performance in the solution of Lamb wave reflection at the edge of semi‐infinite plates, is extended in this paper to a wider range of problems, such as Lamb mode scattering by delaminations and surface defects and SH mode interaction with step discontinuities. Copyright © 2003 John Wiley & Sons, Ltd.