bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrostatic pressure response of polymer-dispersed liquid crystal gratings
Authors: Ermold Michael L. , Rai Kashma , Fontecchio Adam K.
Published: April 2005

Experimental analysis showed shifts in Bragg wavelength when examining the effects of applied hydrostatic pressure (0–10psi above ambient) on the reflection spectrum of holographic polymer-dispersed liquid-crystal Bragg gratings. With increased pressure, a spectral blueshift was observed, suggesting applications in optical pressure sensing. To analyze and quantify the observations, a Gaussian curve was fitted to the reflection spectrum of the gratings at each pressure interval. The spectral dependence on applied pressure is explained by elastic compression of the polymer sections of the Bragg planes in the reflection grating. The presented theory shows that the response of the gratings to the applied pressure is independent of the probe light incidence angle, but is linearly dependent on the ambient pressure reflection wavelength of the gratings.
Evolution of a vortex in glow discharge plasma
Authors: Soukhomlinov V. S. , Sheverev V. A. , Ötügen M. V.
Published: April 2005

The evolution of a vortex in glow discharge plasma is studied analytically. Specifically, the mechanism of local energy deposition into the flow by the plasma is considered and its effect on the structure of an inviscid vortex is analyzed. The vortex is modeled by a set of Euler’s equations while the energy transferred by the plasma into the gas is represented by Rayleigh mechanism. In this mechanism, the amount of heat addition is a function of local gas density. The analysis indicates that the plasma can have a considerable effect on the structure of a vortex. The inviscid calculations show that in a uniform discharge, a 1 cm vortex dies out in a fraction of a second.
Stability of Se passivation layers on Si(001) surfaces characterized by time-of-flight positron annihilation induced Auger electron spectroscopy
Authors: Zhu J. G. , Nadesalingam M. P. , Weiss A. H. , Tao M.
Published: April 2005

The stability of the selenium passivation layer on the Si(001) surface was investigated using a nondestructive surface-sensitive technique: time-of-flight positron annihilation induced Auger electron spectroscopy. After 10days of exposure in the air, the Se passivation layer was observed to incorporate some oxygen but to remain largely intact. Part of the adsorbed oxygen was desorbed during annealing up to 400°C in the ultrahigh-vacuum environment. However, some oxygen remained on the surface until high-temperature annealing at 1030°C. We posit that the oxygen that remained after the low-temperature anneals was chemisorbed on the Si surface at defects in the Se passivation layer. The Se passivation layer was stable up to an annealing temperature of ∼800°C before desorbing from the surface. The stability of the Se-passivated Si(001) surface is attributed to the saturation of the Si dangling bonds on the surface and to the strong Se–Si bonds.
Electronic properties of iron-boron pairs in crystalline silicon by temperature- and injection-level-dependent lifetime measurements
Authors: Birkholz Jens E. , Bothe Karsten , Macdonald Daniel , Schmidt Jan
Published: April 2005

Iron-boron pairs in crystalline silicon are studied by measuring the recombination lifetime as a function of injection density, doping concentration, and temperature. The characteristic crossover point of the injection-level-dependent carrier lifetime curves measured before and after optical dissociation of the iron-boron pairs is analyzed to determine the energy level as well as the electron- and hole-capture cross sections of the acceptor level of iron-boron pairs, assuming known recombination parameters for interstitial iron. The doping concentration dependence of the crossover point gives an electron-capture cross section of (1.4±0.2)×10−14cm2, while the temperature dependence results in a hole-capture cross section in the range from 0.5×10−15to2.5×10−15cm2 and an energy level of (0.26±0.02)eV below the conduction-band edge.
Cylindrical and spherical ion acoustic waves in a plasma with nonthermal electrons and warm ions
Authors: Sahu Biswajit , Roychoudhury Rajkumar
Published: April 2005

Using the reductive perturbation technique, nonlinear cylindrical and spherical Korteweg–de Vries (KdV) and modified KdV equations are derived for ion acoustic waves in an unmagnetized plasma consisting of warm adiabatic ions and nonthermal electrons. The effects of nonthermally distributed electrons on cylindrical and spherical ion acoustic waves are investigated. It is found that the nonthermality has a very significant effect on the nature of ion acoustic waves.
Increased field-emission site density from regrown carbon nanotube films
Authors: Wang Y. Y. , Gupta S. , Liang M. , Nemanich R. J.
Published: April 2005

Electron field-emission properties of as-grown, etched, and regrown carbon nanotube thin films were investigated. The aligned carbon nanotube films were deposited by the microwave plasma-assisted chemical vapor deposition technique. The surface of the as-grown film contained a carbon nanotube mat of amorphous carbon and entangled nanotubes with some tubes protruding from the surface. Hydrogen plasma etching resulted in the removal of the surface layer, and regrowth on the etched surface displayed the formation of a new carbon nanotube mat. The emission site density and the current–voltage dependence of the field emission from all of the samples were analyzed. The results showed that the as-grown sample had a few strong emission spots and a relatively high emission current density (∼20μA∕cm2 at 1V∕μm), while the regrown sample exhibited a significantly increased emission site density.
Vortex triple rings
Authors: Aref Hassan , van Buren Martin
Published: April 2005

We determine equilibrium configurations of interacting point vortices in which identical vortices are arranged on concentric circles and/or form a set of nested regular polygons with or without a vortex at the center. A new analytical method is developed that uses moments of the vortex positions and yields particularly simple results for equilibria of this kind. A complete determination of all triple-ring equilibria is given and numerous previously unknown configurations are identified. Several equilibria previously reported in the literature, found by numerical solution, are characterized analytically.
On the measurement of frequency and of its sample variance with high-resolution counters
Authors: Rubiola Enrico
Published: April 2005

A frequency counter measures the input frequency ν¯ averaged over a suitable time τ, versus the reference clock. High resolution is achieved by interpolating the clock signal. Further increased resolution is obtained by averaging multiple frequency measurements highly overlapped. In the presence of additive white noise or white phase noise, the square uncertainty improves from σν2∝1∕τ2 to σν2∝1∕τ3. Surprisingly, when a file of contiguous data is fed into the formula of the two-sample (Allan) variance σy2(τ)=E{12(y¯k+1−y¯k)2} of the fractional frequency fluctuation y, the result is the modified Allan variance mod σy2(τ). But if a sufficient number of contiguous measures are averaged in order to get a longer τ and the data are fed into the same formula, the results is the (nonmodified) Allan variance. Of course interpretation mistakes are around the corner if the counter internal process is not well understood. The typical domain of interest is the the short-term stability measurement of oscillators.
Portable 543 nm length standard and magnetic-induced zero-crossing shift on length standard transition
Authors: Cheng Wang-Yau , Hu Chun Yi , Shy Jow-Tsong
Published: April 2005

This study reports on the development of a portable iodine-stabilized 543 nm (green) length-standard laser, which is low cost and robust. All the needed optics and electronics were integrated into one box which measured 36 cm in length, 30 cm in width, and 15 cm in height. Simple circuits for third harmonic locking are presented and the laser’s frequency instability could be as small as 2×10−12, normalized to one hertz bandwidth. The influence of the magnetic field to the locking point of the 543 nm length-standard transitions was investigated.
Zonal flow dynamics and anomalous transport
Authors: White Roscoe , Chen Liu , Zonca Fulvio
Published: April 2005

Nonlinear equations for the slow space-time evolution of the radial drift wave-ion-temperature gradient (DW-ITG) envelope and zonal flow (ZF) amplitude have been derived within a coherent four-wave drift wave-zonal flow model. In the local limit this model demonstrates spontaneous generation of zonal flow and nonlinear drift wave-zonal flow dynamics in toroidal plasmas. The model allows slow temporal and spatial variations of the DW-ITG radial envelope, incorporating the effects of equilibrium variations, i.e., turbulence spreading and size dependence of the saturated wave intensities and transport coefficients. The competition between linear drive/damping and drift wave spreading due to linear and nonlinear group velocities and nonlinear energy transfer between DW and ZF determines the saturation levels of the fluctuating fields. The turbulence intensity level exhibits a transition from Bohm scaling at small system size (Lp∕ρi) to gyro-Bohm for large system size. This system exhibits chaotic behavior and intermittency, depending on system size and proximity to marginal stability.
Application of pulse compression signal processing techniques to electromagnetic acoustic transducers for noncontact thickness measurements and imaging
Authors: Ho K. S. , Gan T. H. , Billson D. R. , Hutchins D. A.
Published: April 2005

A pair of noncontact Electromagnetic Acoustic Transducers (EMATs) has been used for thickness measurements and imaging of metallic plates. This was performed using wide bandwidth EMATs and pulse-compression signal processing techniques, using chirp excitation. This gives a greatly improved signal-to-noise ratio for air-coupled experiments, increasing the speed of data acquisition. A numerical simulation of the technique has confirmed the performance. Experimental results indicate that it is possible to perform noncontact ultrasonic imaging and thickness gauging in a wide range of metal plates. An accuracy of up to 99% has been obtained for aluminum, brass, and copper samples. The resolution of the image obtained using the pulse compression approach was also improved compared to a transient pulse signal from conventional pulser/receiver. It is thus suggested that the combination of EMATs and pulse compression can lead to a wide range of online applications where fast time acquisition is required.
High pressure jump apparatus for measuring Grűneisen parameter of NaCl and studying metastable amorphous phase of poly (ethylene terephthalate)
Authors: Hong S. M. , Chen L. Y. , Liu X. R. , Wu X. H. , Su L.
Published: April 2005

A rapid-compression apparatus with a large pressure jump is described. The pressure jump was performed principally by using a large volume bladder-type power accumulator that contains compressed nitrogen and the connected electromagnetic valves. Maximum force induced by the press is 1.1 MN. Within 20 ms the pressure of the sample could be increased from 0.1 to 2.0 GPa in piston-cylinder modules of 26 mm diameter and to 5.8 GPa in Bridgman-type anvils of 26 mm top diameter. The apparatus has been used successfull in determining the Grűneisen parameter of NaCl at high pressures. Furthermore a metastable amorphous phase of poly (ethylene terephthalate) was solidified from its melt in a rapid compressing process; this phase could not be obtained by slow compressing to high pressure or by naturally cooling at ambient pressure.
Chemical and dielectrical characteristics of ultrathin oxides grown by atomic force microscopy and scanning electron beam
Authors: Xie X. N. , Chung H. J. , Sow C. H. , Wee A. T. S.
Published: April 2005

We report a comparative study on the chemical and dielectrical properties of ultrathin oxides grown by atomic force microscopy (AFM) and scanning electron beam (SEB) techniques. Oxide grown by AFM (AFM oxide) shows preferential etching as compared to oxide grown by SEB (SEB oxide). The structural and chemical features of these oxides were probed using time-of-flight secondary ion mass spectrometry (TOF-SIMS) time profiling. It was found that AFM oxide is richer in Si–H and Si–OH content, while SEB oxide is oxygen rich and relatively dense in structure. The dielectric strength of AFM and SEB oxides were further evaluated by conducting AFM (c-AFM). The current–voltage characteristics and dielectric breakdown probability of these oxides were compared. The correlation between Si–H and Si–OH site formation and its impact on the chemical and dielectrical stability of AFM and SEB oxides was discussed.
Three-dimensional electric-field mapping system using crystal principal axes electro-optic rotation
Authors: Kuo Wen-Kai , Tang Deng-Tzung
Published: April 2005

This article presents three-dimensional electric-field mapping measurement system using crystal principal axes electro-optic rotation. An experimental system using a probe tip made of y-cut LiNbO3 crystal is constructed. The mapping measurement results for three directional electric fields on a test device are reported.
Enhanced coercivity in thermally processed (Nd,Dy)(Fe,Co,Nb,B)5.5∕α-Fe nanoscale multilayer magnets
Authors: Liu W. , Li X. Z. , Liu J. P. , Sun X. K. , Chen C. L. , Skomski R. , Zhang Z. D. , Sellmyer D. J.
Published: April 2005

Structural and magnetic properties of laminated (Nd,Dy)(Fe,Co,Nb,B)5.5∕Fe nanocomposites are investigated. Normally, the addition of the soft phase to the hard phase enhances the remanence but deteriorates the permanent-magnet performance of the material by reducing the coercivity. In the present system, the coercivity increases to 1608kA∕m (20.2kOe) in thermally processed Nd–Dy–Fe–Co–Nb–B(15nm)∕Fe(4nm) multilayered nanocomposites, which is higher than that of the single-layer hard-magnetic film. The abnormally high coercivity is achieved by annealing at relatively high temperature, which breaks the laminated structure of the as-deposited multilayer. A likely physical explanation of the enhanced coercivity is the introduction of the domain-wall pinning sites that counteract the inevitable decrease of the nucleation field.
Experimental setup for the measurement of the electrical resistivity and thermopower of thin films and bulk materials
Authors: Boffoué O. , Jacquot A. , Dauscher A. , Lenoir B. , Stölzer M.
Published: April 2005

An experimental setup was developed for the simultaneous measurements of the electrical resistivity and the thermopower in the temperature range going from 77 up to 330K. The system combines accuracy, rapidity, few efforts for the sample mounting, and is fully automated. Pressure contacts are used for contacting the thermocouples to the sample and the sample to the heat sink, making possible the measurement of both thin films and bulk materials with a great flexibility on their geometrical dimensions. Tests of the system have been made on a 99.98% pure Ni bulk sample and on PbTe∕BaF2 thin films for illustration.
Viscous contributions to the pressure for potential flow analysis of capillary instability of two viscous fluids
Authors: Wang J. , Joseph D. D. , Funada T.
Published: April 2005

Capillary instability of a liquid cylinder immersed in another liquid is analyzed using viscous potential flow. An effect of viscosity on the irrotational motion may be introduced by evaluating the viscous normal stress at the liquid–liquid interface on the irrotational motions. In a second approximation, the explicit effects of the discontinuity of the shear stress and tangential component of velocity which cannot be resolved pointwise in irrotational flows, can be removed in the mean from the power of traction integrals in the energy equation by the selection of two viscous corrections of the irrotational pressure. The actual resolution of these discontinuities presumably takes place in a boundary layer which is not computed or needed. We include the irrotational stress and pressure correction in the normal stress balance and compare the computed growth rates to the growth rates of the exact viscous flow solution. The agreement is excellent when one of the liquids is a gas; for two viscous liquids, the agreement is good to reasonable for the maximum growth rates but poor for long waves. Calculations show that good agreement is obtained when the vorticity is relatively small or the irrotational part is dominant in the exact viscous solution. We show that the irrotational viscous flow with pressure corrections gives rise to exactly the same dispersion relation as the dissipation method in which no pressure at all is required and the viscous effect is accounted for by evaluating the viscous dissipation using the irrotational flow.
Development of a laser-based high-precision six-degrees-of-freedom motion errors measuring system for linear stage
Authors: Liu Chien-Hung , Jywe Wen-Yuh , Hsu Cheng-Chung , Hsu Tung-Hui
Published: April 2005

This article presents a useful measuring system for the simultaneous measurement of six-degrees-of-freedom motion errors of a moving stage. The system integrates a miniature fiber coupled laser interferometer with specially designed optical paths and quadrant detectors, capable of measuring six-degrees-of-freedom motion errors. Using this model, the proposed measuring method provides rapid performance, simplicity of setup, and preprocess verification of a linear stage. The experimental setups and measuring procedures, and a systematic calculated method for the error verification are presented in the paper. The system’s resolution of measuring straightness error component is about 25nm. The resolution of measuring the pitch and yaw angular error component is about 0.06arcs. With the comparison between the HP calibration system and the proposed system in the measuring range of 120mm, the system accuracy of measuring straightness error and angular error is within the range ±0.6μm and ±0.3arcs.
High-detectivity InAs quantum-dot infrared photodetectors grown on InP by metal–organic chemical–vapor deposition
Authors: Zhang W. , Lim H. , Taguchi M. , Tsao S. , Movaghar B. , Razeghi M.
Published: April 2005

We report a high-detectivity InAs quantum-dot infrared photodetector. The InAs quantum dots were grown by self-assembly on InP substrates via low-pressure metal–organic chemical–vapor deposition. Highly uniform quantum dots with a density of 4×1010cm2 were grown on a GaAs∕InP matrix. Photoresponse was observed at temperatures up to 160 K with a peak of 6.4μm and cutoff of 6.6μm. Very low dark currents and noise currents were obtained by inserting Al0.48In0.52As current blocking layers. The background-limited performance temperature was 100 K. A detectivity of 1.0×1010cmHz1∕2∕W was obtained at 77 K with a bias of −1.1V.
Broadband InGaAs tapered diode laser sources for optical coherence radar and coherence tomography
Authors: Casel Oliver , Fuchs Harry , Tremont Marc A. , Woll Dirk , Wallenstein Richard
Published: April 2005

This letter reports on broadband laser sources based on InGaAs tapered diode laser amplifiers with external optical feedback. The generated 920nm radiation with a bandwidth of up to 20nm and a power of a few hundred milliwatts is emitted in an almost diffraction limited beam. Spectral filtering and subsequent amplification in a second tapered amplifier provides radiation with spectral widths in the range of 20to40nm and optical output powers of up to 2.5W.
Fair Division or Fair Dinkum? Australian Lessons for Intergovernmental Fiscal Relations in the United Kingdom
Authors: Kay Adrian , Bristow Gillian , McGovern Mark , Pickernell David
Published: April 2005

Current arguments in Australia concerning horizontal fiscal equalisation may help inform the debate in the United Kingdom concerning possible changes to the Barnett formula and the establishment of financial relations with any regional governments in England. Although Australia is a long-established federation, with mature institutions for managing the financial aspects of intergovernmental relations, the most populous states are now pushing for a per-capita-based system to replace the existing formula—based on needs and costs—overseen by the independent Commonwealth Grants Commission. This has important implications for the United Kingdom, where the Barnett formula—a per capita system for deciding annual changes in the funding for the devolved administrations—has been increasingly challenged. In particular, the Barnett system has been vulnerable to nontransparent ‘formula-bypass’ agreements. We argue that the status quo in the United Kingdom appears secure as long as England remains a single entity and the UK Treasury sees the financial implications of larger per capita expenditure in Scotland, Wales, and Northern Ireland as relatively small. However, we speculate that regionalisation of government in England would be likely to increase the pressure: to abandon the Barnett system; to look more systematically at need and cost, rather than population, as criteria for allocating funds between governments; and to move towards an Australian-type system. However, the recent experience of Australia also shows that larger states prefer a per-capita-based system allied to more political, less transparent, arrangements to deal with ‘special circumstances’. It may be that a Barnett-type formula would suit the new ‘dominant states’ in a fully federalised United Kingdom which would, ironically, create an alliance of interests between Scotland and London.
Auroral Contribution to Sky Brightness for Optical Astronomy on the Antarctic Plateau
Authors: Dempsey J. T. , Storey J. W. V. , Phillips A.
Published: April 2005

The Antarctic Plateau holds great promise for optical astronomy. One relatively unstudied feature of the polar night sky for optical astronomical observing is the potential contamination of observations by aurorae. In this study we analyse auroral measurements at South Pole Station and show that during an average winter season, the auroral contribution to the B band sky brightness is below 21.9 B mag arcsec−2 for 50% of the observing time. In V band, the median sky brightness contribution is 20.8 mag arcsec−2 during an average winter. South Pole Station is situated within the auroral zone and experiences strong and frequent auroral activity. The Antarctic locations of Dome C and Dome A are closer to the geomagnetic pole where auroral activity is greatly reduced compared with that of South Pole Station. Calculations based on satellite measurements of electron flux above the Antarctic Plateau are used to show that at Dome C, the contribution to sky background in the B and V bands is up to 3.1 mag less than that at the South Pole. The use of notch filters to reduce the contribution from the strongest auroral emission lines and bands is also discussed. The scientific potential of an extremely large telescope located at Dome C is discussed, with reference to the effect that auroral emissions would have on particular astronomical observations.
Neutrophil microtubules suppress polarity and enhance directional migration
Authors: Xu Jingsong , Wang Fei , Van Keymeulen Alexandra , Rentel Maike , Bourne Henry R.
Published: April 2005

How do microtubules, which maintain and direct polarity of many eukaryotic cells, regulate polarity of blood neutrophils? In sharp contrast to most cells, disrupting a neutrophil's microtubule network with nocodazole causes it to polarize and migrate [Niggli, V. (2003)J. Cell Sci.116, 813–822]. Nocodazole induces the same responses in differentiated HL-60 cells, a model neutrophil cell line, and reduces their chemotactic prowess by causing them to pursue abnormally circuitous paths in migrating toward a stationary point source of an attractant, f-Met-Leu-Phe (fMLP). The chemotactic defect stems from dramatic nocodazole-induced imbalance between the divergent, opposed fMLP-induced “backness” and “frontness” signals responsible for neutrophil polarity. Nocodazole (i) stimulates backness by increasing Rho- and actomyosin-dependent contractility, as reported by Niggli, and also (ii) impairs fMLP-dependent frontness: pseudopods are flatter, contain less F-actin, and show decreased membrane translocation of PH-Akt-GFP, a fluorescent marker for 3′-phosphoinositide lipids. Inhibiting backness with a pharmacologic inhibitor of a Rho-dependent kinase substantially reverses nocodazole's effects on chemotaxis, straightness of migration paths, morphology, and PH-Akt-GFP translocation. Thus, microtubules normally balance backness vs. frontness signals, preventing backness from reducing the strength of pseudopods and from impairing directional migration.
bptA(bbe16) is essential for the persistence of the Lyme disease spirochete,Borrelia burgdorferi, in its natural tick vector
Authors: Revel Andrew T. , Blevins Jon S. , Almazán Consuelo , Neil Lori , Kocan Katherine M. , de la Fuente José , Hagman Kayla E. , Norgard Michael V.
Published: April 2005

Borrelia burgdorferi(Bb), the agent of Lyme disease, is a zoonotic spirochetal bacterium that depends on arthropod (Ixodesticks) and mammalian (rodent) hosts for its persistence in nature. The quest to identify borrelial genes responsible forBb's parasitic dependence on these two diverse hosts has been hampered by limitations in the ability to genetically manipulate virulent strains ofBb. Despite this constraint, we report herein the inactivation and genetic complementation of a linear plasmid-25-encoded gene (bbe16) to assess its role in the virulence, pathogenesis, and survival ofBbduring its natural life cycle.bbe16was found to potentiate the virulence ofBbin the murine model of Lyme borreliosis and was essential for the persistence ofBbinIxodes scapularisticks. As such, we have renamedbbe16a gene encoding borrelial persistence in ticks (bpt)A. Although protease accessibility experiments suggested that BptA as a putative lipoprotein is surface-exposed on the outer membrane ofBb, the molecular mechanism(s) by which BptA promotesBbpersistence within its tick vector remains to be elucidated. BptA also was shown to be highly conserved (>88% similarity and >74% identity at the deduced amino acid levels) in allBb sensu latostrains tested, suggesting that BptA may be widely used by Lyme borreliosis spirochetes for persistence in nature. GivenBb's absolute dependence on and intimate association with its arthropod and mammalian hosts, BptA should be considered a virulence factor critical forBb's overall parasitic strategy.
Colonial Legacies
Authors: Pennington Brian K.
Published: April 2005

This final chapter makes the case for the retention of certain received categories and approaches in the study of Hindu traditions in response to the recent critiques of several western scholars who argue that terms such as “Hinduism” and “religion” cannot find meaningful analogues in Indian traditions, and that scholars in the history of religions ought to dispense with them. In some instances, utterly dismissive of religious faith, practice, or identity, this deconstruction of widely accepted categories is not without significant political ramifications, as seen in recent literatures of Christian missionaries and Hindu nationalism. In an atmosphere of global religious upheaval and transformation, this attack on these categories promises only to exacerbate the clash of identities and communities with one another and with the secular academy. Europe, North America, and India are all in need of new models for structuring the relationship of religion and citizenship, a task in which Hindu-Christian dialogue can play an important role. The simultaneous estrangement of religious communities from public life and nationalization of religious identity speak to the tensions inherent in the loyalties demanded by religious faith and citizenship. Some trends in religious studies today seem to offer not solutions to this impasse, but rather encouragement to further talking at cross purposes.
The HDG-machine: a highly distributed graph-reducer for a transputer network
Authors: Kingdon H. , Lester D. R. , Burn G. L.
Published: April 2005

Distributed implementations of programming languages with implicit parallelism hold out the prospect that the parallel programs are immediately scalable. This paper presents some of the results of our part of Esprit 415, in which we considered the implementation of lazy functional programming languages on distributed architectures.

A compiler and abstract machine were designed to achieve this goal. The abstract parallel machine was formally specified, using Miranda. Each instruction of the abstract machine was then implemented as a macro in the Transputer Assembler. Although macro expansion of the code results in non-optimal code generation, use of the Miranda specification makes it possible to validate the compiler before the Transputer code is generated.

The hardware currently available consists of five T800-25s, each board having 16 Mbytes of memory. Benchmark timings using this hardware are given. In spite of the straightforward code-generation, the resulting system compares favourably with more sophisticated sequential implementations, such as that of LML.
Malabsorption of Carbohydrates and Depression in Children and Adolescents
Authors: Varea Vicente , de Carpi Javier Martín , Puig Conchita , Alda José Angel , Camacho Eva , Ormazabal Aida , Artuch Rafael , Gómez Lilianne
Published: April 2005

Background:

Previous studies have shown an association between sugar malabsorption and depressive symptoms in adult women. Incompletely absorbed sugars may form nonabsorbable complexes with tryptophan, an amino acid precursor of serotonin, decreasing its availability. As serotonin is the most important neurotransmitter involved in depressive disorders, its depletion could lead to the onset of depression.

Methods:

The authors' aim was to study the possible association between malabsorption of sugars (lactose and fructose) and depressive symptoms in adolescent patients of Spanish origin. The authors studied two groups of patients. Group G included 14 patients previously diagnosed with sugar intolerance. In these, the authors assessed depressive symptoms. Group P consisted of seven patients suffering from major depression. In these, the authors performed functional sugar absorption tests. The authors studied the metabolic pathway of tryptophan in both groups.

Results:

In the group with sugar malabsorption, there was a 28.5% prevalence of depressive symptoms that was higher than expected in our population. In the group with depression, the authors found a higher than expected prevalence of sugar intolerance (71.42% versus 15% in controls).

Conclusions:

The unexpected prevalences obtained for the groups studied suggest that there may be an association between sugar intolerance and depressive symptoms during adolescence.
Cognitive Preference Reversal or Market Price Reversal?
Authors: Chai Xiaoyong
Published: April 2005

Preference Reversal Phenomenon (PRP) has been most often scrutinized as a puzzle of ‘preferences’, while the discovery of the ‘endowment effect’ explicitly questions the parity between preference and price. The author's experiment (N = 186) connects these two extraordinary findings and illustrates that PRP is only a reversal of price in a ‘market.’ PRP merely proves that subjects demand to be compensated based on loss under market access deprivation when a ‘maximum buying’/‘minimum selling’ price is elicited, and preference transitivity is restored once the misleading market manipulation is experimentally controlled.

By defending preference transitivity, the author asserts that normal access to the bargaining process is indispensable for a competitive market where preference price parity is required.

To make valid measurements of preference and price, the sealed envelope method is substituted for the judged‐indifferent‐point (JIP) method, and the binding statement method is substituted for the Becker‐DeGroot‐Marschack method. McNemar test scores are calculated to compare the effects of different methods.
Viability, Economic Transition and Reflection on Neoclassical Economics*
Authors: Lin Justin Yifu
Published: April 2005

Many transition policies, based on the existing neoclassical economic theories, failed in Eastern Europe, the former Soviet Union, and China. This paper argues that the failure is due to the implicit viability assumption of neoclassical economics. The existing neoclassical economics implicitly assumes that a firm is expected to earn a socially acceptable profit in an open, competitive market as long as the firm has normal management. However, many firms in socialist as well as transitional economies are not viable, that is, they will not be able to earn a socially acceptable profit in an open, competitive market even if they are under normal management because they are in sectors that are inconsistent with their economies' comparative advantages. Under the viability assumption, neoclassical‐based reform policies focus on issues related to property rights, corporate governance, government interventions and other issues that may obstruct a firm's normal management. However, many of these issues are in fact endogenous to the firms' viability problem. Therefore, without resolving the firms' viability problem, such reforms fail to achieve their intended goals. Not only in socialist and transition economies but also in many developing economies there exist many nonviable firms. This paper suggests that the viability assumption in neoclassical economics should be relaxed when analyzing socialist, transition and developing economies.
Foreign Direct Investment and Regional Economic Performance
Authors: Mullen John K. , Williams Martin
Published: April 2005

Although foreign direct investment into developed economies continues to show dramatic growth, little consensus exists over either its national or regional impacts. The lack of empirical evidence, particularly on a sub‐national level, adds to the uncertainty over the efficacy of regional development strategies focused on attracting foreign investment. The present research uses book value and employment measures of U.S. state‐level FDI activity to assess the impact of foreign capital on regional growth and productivity performance. The results imply a vital role for FDI in stimulating regions within well‐integrated, developed economies.
The Role of Audiovisual Speech and Orthographic Information in Nonnative Speech Production
Authors: Erdener V. Doǧu , Burnham Denis K.
Published: April 2005

Visual information from the face is an integral part of speech perception. Additionally, orthography can play a role in disambiguating the speech signal in nonnative speech. This study investigates the effect of audiovisual speech information and orthography on nonnative speech. Particularly, orthographic depth is of interest. Turkish (transparent) and Australian English (opaque) speakers were tested for their production of nonwords in Spanish (transparent) and Irish (opaque). We found that transparent orthography enhanced pronunciation and orthographic responses. Results confirm previous findings that visual information enhances speech production and extend them to show the facilitative effects of orthography under certain conditions. Implications are discussed in relation to audiovisual speech perception and orthographic processing and practical considerations such as second language instruction.
Metalorganic Chemical Vapor Deposition by Pulsed Liquid Injection Using an Ultrasonic Nozzle: Titanium Dioxide on Sapphire from Titanium(IV) Isopropoxide
Authors: Versteeg Vera A. , Avedisian C. Thomas , Raj Rishi
Published: April 2005

A new method for metalorganic chemical vapor deposition has been developed in which a precursor solution is directly injected into a reaction chamber. The vaporization of short pulses of liquid is facilitated by atomization with a piezo‐electrically operated nozzle. The system has been used successfully to grow oriented, thin TiO2 (rutile) films on sapphire substrates with the crystalline relationship (101)[010]R || (1120)[0001]s. A film growth rate of approximately 2.5 monolayers of TiO2 (rutile) per pulse was achieved at 650°C for a reactant impingement rate of about 250 monolayers of Ti(OPri)4 per pulse.
Vitamin D and calcium deficits predispose for multiple chronic diseases
Authors: Peterlik M. , Cross H. S.
Published: April 2005

There is evidence from both observational studies and clinical trials that calcium malnutrition and hypovitaminosis D are predisposing conditions for various common chronic diseases. In addition to skeletal disorders, calcium and vitamin D deficits increase the risk of malignancies, particularly of colon, breast and prostate gland, of chronic inflammatory and autoimmune diseases (e.g. insulin‐dependent diabetes mellitus, inflammatory bowel disease, multiple sclerosis), as well as of metabolic disorders (metabolic syndrome, hypertension). The aim of the present review was to provide improved understanding of the molecular and cellular processes by which deficits in calcium and vitamin D cause specific changes in cell and organ functions and thereby increase the risk for chronic diseases of different aetiology. 1,25‐dihydroxyvitamin D3 and extracellular Ca++ are both key regulators of proliferation, differentiation and function at the cellular level. However, the efficiency of vitamin D receptor‐mediated intracellular signalling is limited by the negative effects of hypovitaminosis D on extrarenal 25‐hydroxyvitamin D‐1α‐hydroxylase activity and thus on the production of 1,25‐dihydroxyvitamin D3. Calcium malnutrition eventually causes a decrease in calcium concentration in extracellular fluid compartments, resulting in organ‐specific modulation of calcium‐sensing receptor activity. Hence, attenuation of signal transduction from the ligand‐activated vitamin D receptor and calcium‐sensing receptor seems to be the prime mechanism by which calcium and vitamin D insufficiencies cause perturbation of cellular functions in bone, kidney, intestine, mammary and prostate glands, endocrine pancreas, vascular endothelium, and, importantly, in the immune system. The wide range of diseases associated with deficits in calcium and vitamin D in combination with the high prevalence of these conditions represents a special challenge for preventive medicine.
Factors predicting the development of metabolic syndrome and type II diabetes against a background of hypertension
Authors: Lim H. S. , Lip G. Y. H. , Beevers D. G. , Blann A. D.
Published: April 2005

Background  The metabolic syndrome (MetS), predicting coronary heart disease (CHD), is a compound of risk factors including diabetes, obesity and hypertension. The relationship between the development of MetS, diabetes and CHD in patients with established hypertension is unclear. We hypothesized that patients with hypertension developing MetS are at increased risk of type II diabetes and CHD compared with patients who do not develop MetS.

Materials and methods  We prospectively studied 284 patients (100 with existing/established MetS) with hypertension but without diabetes and CHD over 4 years. MetS and diabetes were diagnosed by the modified NCEP and ADA criteria, and CHD risk by the Framingham risk equation; all patients had annual fasting blood sampling.

Results  Over 4 years of follow up, 75 of the 184 patients (41%) initially free of MetS at baseline subsequently fulfilled the criteria for MetS. These patients (i.e. ‘developing MetS’) had higher baseline BMI, triglycerides and lower HDL cholesterol, with a higher calculated CHD risk (all P ≤ 0·001) than those who did not develop MetS. The 4‐year odds ratios of developing diabetes in the patients with established MetS (23%) and the patients developing MetS (13·3%) vs. the patients not developing MetS (3·7%, P < 0·001) were 7·8 (95% CI: 2·6–23·5) and 4·0 (95% CI: 1·2–13·4), respectively.

Conclusions  Patients with hypertension developing MetS have an increased CHD risk and risk of developing type II diabetes even before fulfilling the criteria for MetS, and the former is comparable to patients with established MetS. These data suggest a high‐risk phase not adequately identified by current diagnostic thresholds for MetS.
An application of canonical correspondence analysis for developing ecological quality assessment metrics for river macrophytes
Authors: DODKINS IAN , RIPPEY BRIAN , HALE PETER
Published: April 2005

1. Aquatic macrophyte composition and abundance is required by the European Union's Water Framework Directive for determining ecological status. Five metrics were produced that can be combined to determine the deviation of aquatic macrophytes from reference conditions in Northern Ireland's rivers.

2. Species optima and niche breadths along silt, nitrate, pH, conductivity and dissolved oxygen gradients were generated from aquatic macrophyte and water quality surveys conducted at 273 sites throughout Northern Ireland using Canonical Correspondence Analysis (CCA). Five metric scores based on these environmental gradients were determined at new monitoring sites using the mean optima of the species occurring at the site, weighted by percentage cover and niche breadth of each species.

3. A preliminary reference network of 32 sites of high physico‐chemical and hydromorphological quality, and representative of the range of river types in Northern Ireland, enabled reference metric scores to be produced for each river type. Five unimpacted and twenty impacted sites were used for testing the performance of the metrics. By subtracting reference metric scores from metric scores at a monitoring site measures of ecological impact could be determined along five different impact gradients. Metrics were also combined to give a measure of total ecological change.

4. The metrics system distinguished unimpacted from impacted sites and correctly identified 77% of the known impacts. The metrics distinguished different types of impact, e.g. silt and nitrate.

5. Aquatic macrophyte occurrence and abundance has high natural variability at a site, both temporally and spatially. This method was designed to be sensitive to ecological change whilst reducing noise caused by natural variation.
Beringia as a glacial refugium for boreal trees and shrubs: new perspectives from mapped pollen data
Authors: Brubaker Linda B. , Anderson Patricia M. , Edwards Mary E. , Lozhkin Anatoly V.
Published: April 2005

Aim Beringia, far north‐eastern Siberia and north‐western North America, was largely unglaciated during the Pleistocene. Although this region has long been considered an ice‐age refugium for arctic herbs and shrubs, little is known about its role as a refugium for boreal trees and shrubs during the last glacial maximum (LGM,c. 28,000–15,000 calibrated years before present). We examine mapped patterns of pollen percentages to infer whether six boreal tree and shrub taxa (Populus,Larix,Picea,Pinus,Betula,Alnus/Duschekia) survived the harsh glacial conditions within Beringia.

Methods Extensive networks of pollen records have the potential to reveal distinctive temporal–spatial patterns that discriminate between local‐ and long‐distance sources of pollen. We assembled pollen records for 149 lake, peat and alluvial sites from the Palaeoenvironmental Arctic Sciences database, plotting pollen percentages at 1000‐year time intervals from 21,000 to 6000 calibrated years before present. Pollen percentages are interpreted with an understanding of modern pollen representation and potential sources of long‐distance pollen during the glacial maximum. Inferences from pollen data are supplemented by published radiocarbon dates of identified macrofossils, where available.

Results Pollen maps for individual taxa show unique temporal‐spatial patterns, but the data for each taxon argue more strongly for survival within Beringia than for immigration from outside regions. The first increase ofPopuluspollen percentages in the western Brooks Ranges is evidence thatPopulustrees survived the LGM in central Beringia. Both pollen and macrofossil evidence supportLarixsurvival in western Beringia (WB), but data forLarixin eastern Beringia (EB) are unclear. Given the similar distances of WB and EB to glacial‐age boreal forests in temperate latitudes of Asia and North America, the widespread presence ofPiceapollen in EB andPinuspollen in WB indicates thatPiceaandPinussurvived within these respective regions.Betulapollen is broadly distributed but highly variable in glacial‐maximum samples, suggesting thatBetulatrees or shrubs survived in restricted populations throughout Beringia.Alnus/Duschekiapercentages show complex patterns, but generally support a glacial refugium in WB.

Main conclusions Our interpretations have several implications, including: (1) the rapid post‐glacial migration rate reported forPiceain western Canada may be over estimated, (2) the expansion of trees and shrubs within Beringia should have been nearly contemporaneous with climatic change, (3) boreal trees and shrubs are capable of surviving long periods in relatively small populations (at the lower limit of detection in pollen data) and (4) long‐distance migration may not have been the predominant mode of vegetation response to climatic change in Beringia.
Response of semi‐desert grasslands invaded by non‐native grasses to altered disturbance regimes
Authors: Geiger Erika L. , McPherson Guy R.
Published: April 2005

Aim  Using a long‐term data set we investigated the response of semi‐desert grasslands to altered disturbance regimes in conjunction with climate patterns. Specifically, we were interested in the response of a non‐native grass (Eragrostis lehmanniana), mesquite (Prosopis velutina), and native species to the reintroduction of fire and removal of livestock.

Location  The study site is located on the 45,360‐ha Buenos Aires National Wildlife Refuge (31°32′ N, 110°30′ W) in southern Arizona, USA. In 1985, livestock were removed and prescribed fires were reintroduced to this semi‐desert grassland dominated by non‐native grasses and encroaching mesquite trees.

Methods  Plant species cover was monitored along 38, 30‐m transects five times over a period of 15 years. Data were analysed using principal components analysis on the variance–covariance and correlation matrix, multivariate analysis of variance for changes over time in relation to environmental data, and analysis of variance for altered disturbance regimes.

Results  Reintroduction of fire and removal of livestock have not led to an increase in native species diversity or a decrease in non‐native grasses or mesquite. The cover of non‐native grass was influenced by soil type in 1993.

Main conclusions  Variability of plant community richness, diversity, and cover over time appear to be most closely linked to fluctuations in precipitation rather than human‐altered disturbance regimes. The effects of altered grazing and fire regimes are likely confounded by complex interactions with climatic factors in systems significantly altered from their original physiognomy.