bluuebunny/crossref_metadata_2025 huggingface dataset:
HAVEGE
Authors: Seznec André , Sendrier Nicolas
Published: October 2003

Random numbers with high cryptographic quality are needed to enhance the security of cryptography applications. Software heuristics for generating empirically strong random number sequences rely on entropy gathering by measuring unpredictable external events. These generators only deliver a few bits per event. This limits them to being used as seeds for pseudorandom generators.General-purpose processors feature a large number of hardware mechanisms that aim to improve performance: caches, branch predictors, …. The state of these components is not architectural (i.e., the result of an ordinary application does not depend on it). It is also volatile and cannot be directly monitored by the user. On the other hand, every operating system interrupt modifies thousands of these binary volatile states.In this article, we present and analyze HAVEGE (HArdware Volatile Entropy Gathering and Expansion), a new user-level software heuristic to generate practically strong random numbers on general-purpose computers. The hardware clock cycle counter of the processor can be used to gather part of the entropy/uncertainty introduced by operating system interrupts in the internal states of the processor. Then, we show how this entropy gathering technique can be combined with pseudorandom number generation in HAVEGE. Since the internal state of HAVEGE includes thousands of internal volatile hardware states, it seems impossible even for the user itself to reproduce the generated sequences.
Predicting behaviour from perceived behavioural control: Tests of the accuracy assumption of the theory of planned behaviour
Authors: Sheeran Paschal , Trafimow David , Armitage Christopher J.
Published: October 2003

The theory of planned behaviour assumes that the accuracy of perceived behavioural control (PBC) determines the strength of the PBC‐behaviour relationship. However, this assumption has never been formally tested. The present research developed and validated a proxy measure of actual control (PMAC) in order to test the assumption. In two studies, participants completed measures of intention and PBC, and subsequently completed measures of behaviour and the PMAC. Validity of the PMAC was established by findings showing; (a) that the PMAC moderated the intention‐behaviour relation, and (b) that PMAC scores did not reflect attributions for participants' failure to enact their stated intentions. Accuracy was operationalized as the difference between PBC and PMAC scores. Consistent with theoretical expectations, several analyses indicated that greater accuracy of PBC was associated with improved prediction of behaviour by PBC.
ISO 14001 EMS standard registration decisions among Canadian organizations
Authors: Yiridoe Emmanuel K. , Clark J. Stephen , Marett Geb E. , Gordon Robert , Duinker Peter
Published: October 2003

This study characterized the costs and benefits associated with adopting ISO 14001 environmental management system (EMS) standard, based on a survey of ISO 14001‐registered organizations in Canada. Decision makers are contemplating whether it is necessary to register to one or more of the ISO and other international standards and, if so, which ones. Furthermore, an organization that has registered separate departments to different standards and contemplates integrating such standards across the different units may be interested in attributes of particular units that will facilitate integration. Discriminant analysis was conducted to characterize the factors that distinguish between organizations that adopted ISO 14001 alone (single standard), versus those that registered to ISO 14001 along with other quality, health, and safety standards (i.e., multiple standards). The most important factor that motivated adoption to ISO 14001 was to establish a positive environmental profile, thereby promoting goodwill and integrity. Internal factors tended to dominate the motivations for adopting ISO 14001, supporting the hypothesis that external benefits may not be fully realized due to market and policy failure. Internal costs associated with registration depended on the size of the organization and ranged, on average, from CND$17,000 (for organizations with less than 100 employees), to CND$42,000 (for organizations with more than 500 employees). External costs depended more on the type (i.e., sector of the Canadian economy) than on size of the organization. The most important variable that distinguished between Canadian organizations that adopted ISO 14001 alone versus those that adopted ISO 14001 and other standards was whether the organization had an international orientation, that is, those with more than 50% of services or exports to other countries. [EconLit citations: L150, L200, Q290]. © 2003 Wiley Periodicals, Inc. Agribusiness 19: 439–457, 2003.
Correlates of falls and fear of falling among adults with rheumatoid arthritis
Authors: Jamison Marian , Neuberger Geri B. , Miller Peggy A.
Published: October 2003

Objective

To identify correlates of falling and fear of falling, and to examine how fear of falling affects activities among adults with rheumatoid arthritis (RA).

Methods

Adults (mean age 54.2 years; SD 9.1) with RA (n = 128) responded to questions related to falls, fear of falling, and activities modified. Other measures included the Profile of Mood States Short Form, the McGill Pain Questionnaire Short Form, walk time, grip strength, predicted maximum oxygen uptake, and joint count.

Results

Thirty‐five percent of participants fell during the previous year. Subjects who fell had more comorbid conditions than subjects who did not fall. Almost 60% were fearful of falling. Compared with subjects who denied fear of falling, fearful subjects had longer walk times, more comorbid conditions, and more intense pain. Activities affected most by fear of falling involved heavy work and climbing.

Conclusions

The number of comorbid conditions plays an important role in falling and fear of falling in adults with RA. Knowledge of this and other factors, such as pain intensity and functional status, can facilitate appropriate interventions.
Glucocorticoid therapy in giant cell arteritis: Duration and adverse outcomes
Authors: Proven Anne , Gabriel Sherine E. , Orces Carlos , O'Fallon W. Michael , Hunder Gene G.
Published: October 2003

Objective

To evaluate the course of glucocorticoid (GC) therapy and associated adverse events in a population‐based cohort of patients with giant cell arteritis (GCA).

Methods

We identified 125 Olmsted County residents with GCA diagnosed between 1950 and 1991 and obtained followup information on the 120 patients who were diagnosed antemortem and agreed to participate in this study. Clinical variables, GC doses, and GC adverse events on each patient were recorded. The relationship between GC therapy and the development of adverse events was studied by the Cox and Anderson‐Gill proportional hazards models.

Results

All patients were treated with GCs and responded rapidly (median initial dosage 60 mg prednisone/day). The dosage was later reduced according to the treating physicians' judgment. The median duration required to reach 7.5 mg/day was 6.5 months and the median duration required to reach 5 mg/day was 7.5 months. Relapses or recurrences occurred in 57 patients. For the 87 patients followed to discontinuation of GC therapy and permanent remission of GCA (median of 22 months), the total median dose of prednisone was 6.47 gm. Adverse events associated with GCs were recorded in 103 (86%) patients and 2 or more events occurred in 70 patients (58%). Age and higher cumulative dose of GCs were associated with the development of adverse GC side effects.

Conclusion

GCs are therapeutically effective in GCA and the prednisone dosage was reduced to physiologic levels in three‐fourths of the patients within 1 year. However, most patients developed serious adverse side effects related to GCs, indicating that less toxic therapeutic measures are needed.
Mass Transfer In Trickle‐Bed Reactors With Structured Packing
Authors: Battista J. , Böhm U.
Published: October 2003

An experimental investigation was carried out to examine the fluid dynamic and mass transfer behavior of structured packing, with the liquid and gas phase flowing co‐currently downwards in the column. Liquid to packing mass transfer coefficients for three positions within the pack were measured by an electrochemical method, varying both the liquid and gas loads as well as the physical properties of the liquid phase. Due to the high void fraction of structured packing, much higher liquid flow rates can be used than in traditional particle trickle‐beds. It was found that in the range studied, the gas superficial velocity has no effect on the mass transfer rate and thus, a general mass transfer correlation in terms of liquid Reynolds number only, was developed. Wetted areas and the radial distribution of liquid through the packing element were determined by a colorimetric method. Within the range of liquid flow rates investigated, complete wetting is not achieved, even with the low viscosity solutions. The measured ratios of hydraulic to geometric area, agree reasonably well with values predicted by existing relationships.
Comparison of Hydrodynamics and Mass Transfer in Airlift and Bubble Column Reactors Using CFD
Authors: van Baten J.M. , Krishna R.
Published: October 2003

Computational Fluid Dynamics (CFD) is used to compare the hydrodynamics and mass transfer of an internal airlift reactor with that of a bubble column reactor, operating with an air/water system in the homogeneous bubble flow regime. The liquid circulation velocities are significantly higher in the airlift configuration than in bubble columns, leading to significantly lower gas holdups. Within the riser of the airlift, the gas and liquid phases are virtually in plug flow, whereas in bubble columns the gas and liquid phases follow parabolic velocity distributions. When compared at the same superficial gas velocity, the volumetric mass transfer coefficient, kLa, for an airlift is significantly lower than that for a bubble column. However, when the results are compared at the same values of gas holdup, the values of kLa are practically identical.
Three‐Dimensional Numerical Simulation of Flow‐Induced Tube Bundle Vibration
Authors: Fischer M.
Published: October 2003

Efforts have been made to increase thermal efficiency of tube bundle heat exchangers by increasing flow velocities and decreasing tube wall thicknesses, which led to a number of damages due to flow‐induced vibrations. Here, a numerical tool is presented which, for the first time, makes it possible to simulate fluid‐structure‐coupled vibrations in tube bundles in three dimensions. This tool has the potential to optimize tube bundle structures such that thermal efficiency is improved in terms of economy and safety.
Effect of Peripheral Substitution on the Electronic Absorption and Fluorescence Spectra of Metal‐Free and Zinc Phthalocyanines
Authors: Kobayashi Nagao , Ogata Hiroshi , Nonaka Naokazu , Luk'yanets Eugene A.
Published: October 2003

The effect of substituents on the position and intensity of the electronic absorption and fluorescence spectra of phthalocyanines (Pcs) was examined for 35 Pc compounds. When electron‐releasing groups are bound to four α‐benzo positions of the Pc skeleton, the B and Q bands shift to longer wavelength. Relative to this shift, the effect of introducing the same electron‐releasing groups at the other four α positions amounts to about 1.6–2.0. Although the effect is not always clearly seen, introduction of electron‐releasing groups in the β‐benzo positions of the Pc skeleton generally shifts the Q band to shorter wavelength. The effect of electron‐withdrawing groups is exactly the opposite with respect to the α and β positions. These effects can be reasonably explained by considering the magnitude of the atomic orbital coefficients of the carbon atoms derived from molecular orbital (MO) calculations. In addition, the following intriguing phenomena were observed in the experiments, although not all were explained theoretically: 1) the splitting of the Q band of metal‐free Pcs decreases with increasing wavelength of the Q band, 2) the ring currents of Pcs with Q bands at longer wavelength are generally smaller, and 3) the absorption coefficients of the Q band of Pc compounds with 16‐electron‐releasing substituents are larger than those of the corresponding tetra‐ and octasubstituted Pcs by several tens of percent. 4) Our PPP calculations suggested that the absorption coefficient of the Q band of Pcs with more strongly electron releasing substituents is larger. 5) The second HOMO of the Pcs with the Q band at longer wavelength has b1u symmetry, as opposed to the a2u symmetry of normal Pcs. 6) Pcs showing S1 emission maxima at wavelengths longer than about 740 nm generally have quantum yields of less than 0.1.
Discrimination of Peptides by Using a Molecularly Imprinted Piezoelectric Biosensor
Authors: Lin Chung‐Yin , Tai Dar‐Fu , Wu Tzong‐Zeng
Published: October 2003

Based on the direct formation of a molecularly imprinted polymer on gold electrodes, we have developed a peptide sensor for the detection of low‐molecular‐weight peptides. A new cross‐linking monomer, (N‐Acr‐L‐Cys‐NHBn)2, was employed to attach the surface of the chip and to copolymerize with other monomers. Interestingly, N‐benzylacrylamide participates in the polymerization and recognition is carried out in an aqueous environment. By using quartz crystal microbalance detection, short peptides can be monitored by their interaction with plastic antibodies specific for the target peptides. The selectivity of molecularly imprinted polymers and the sensitivity of such artificial biosensors have been combined to differentiate between traces of oxytocin and vasopressin to the ng mL−1 scale.
“Janus” Supermolecular Liquid Crystals—Giant Molecules with Hemispherical Architectures
Authors: Saez Isabel M. , Goodby John W.
Published: October 2003

Liquid crystals represent a unique class of self‐organising systems, which although found in many day‐to‐day practical material applications, such as displays, are also intimately entwined with living processes. They have the potential, just like living systems, to provide us with a unique vehicle for the development of self‐ordering nano‐ and mesoscopic‐engineered materials with specific functional properties. In this article we describe a new concept for the design of self‐assembling functional liquid crystals as segmented or “Janus” liquid‐crystalline supermolecular materials in the form of structures that contain two different types of mesogenic units, which favour different types of mesophase structure, grafted onto the same star‐shaped scaffold to create supermolecules that contain different hemispheres. The materials exhibit chiral nematic and chiral smectic C phases.
Tailoring the Catalytic Performance of Sol–Gel‐Encapsulated Tetra‐n‐propylammonium Perruthenate (TPAP) in Aerobic Oxidation of Alcohols
Authors: Ciriminna Rosaria , Pagliaro Mario
Published: October 2003

Sol–gel nanohybrid silica particles organically modified and doped with the ruthenium species tetra‐n‐propylammonium perruthenate (TPAP) are highly efficient catalysts for the selective oxidation of alcohols to carbonyl groups with O2 at low pressure in toluene. The materials are easily prepared by a one‐step sol–gel process, and their catalytic performance can be optimised by tailoring the conditions of their synthesis by hydrolytic co‐polycondensation of tetramethoxysilane (TMOS) and alkyltrimethoxysilanes R‐Si(OMe)3 in the presence of TPAP. Eventually, heterogeneous catalysts considerably more active than the unsupported perruthenate were obtained, while also being leach‐proof and recyclable. The correlation between the materials' activity, surface polarity and textural properties suggests valuable information on the chemical behaviour of sol–gel catalytic materials in oxidation catalysis; this is of interest in view of the importance of efficient solid catalysts for the selective oxidation of alcohols with O2.
Contributions of Yuri L. Klimontovich to the kinetic theory of nonideal plasmas
Authors: Bonitz M. , Ebeling W. , Romanovsky Yu. M.
Published: October 2003

We give a short summary of live and work of Yuri L. Klimontovich (1924–2002), in particular we discuss his work on nonideal plasma physics. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Einstein frequency distributions for strongly coupled plasmas
Authors: Bakshi P. , Donkó Z. , Kalman G. J.
Published: October 2003

Einstein frequencies of strongly coupled plasma systems are investigated theoretically, and through molecular dynamics simulations. Expressions are derived that connect the deviations from local order to the Einstein frequencies. A scaling relation is obtained for the spread of the frequency distribution as a function of the coupling strength. Theoretical results are compared with simulations. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fluctuation‐dissipation‐dispersion relations for a nonuniform plasma
Authors: Belyi V.V.
Published: October 2003

Using the Langevin approach and the multiscale technique, a kinetic theory of the time and space nonlocal fluctuations in the collisional plasma is constructed. In local equilibrium a generalized version of the Callen‐Welton theorem is derived. It is shown that not only the dissipation but also the time and space derivatives of the dispersion determine the amplitude and the width of the spectrum lines of the electrostatic field fluctuations, as well as the form factor. There appear significant differences with respect to the non‐uniform plasma. In the kinetic regime the form factor is more sensible to space gradient than the spectral function of the electrostatic field fluctuations. As a result of the inhomogeneity, these proprieties became asymmetric with respect to the inversion of the frequency sign. The differences in amplitude of peaks could become a new tool to diagnose slow time and space variations in the plasma. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
2‐ion and 3‐ion neighbor spatial distribution functions in plasmas
Authors: Fisher D.V. , Maron Y.
Published: October 2003

Accurate treatment of the plasma density effects requires a detailed knowledge of spatial distribution of individual ions around a test ion. The 2‐body and 3‐body distribution functions involving the nearest neighbor (NN) and the next‐nearest neighbor (NNN) ions have recently been derived [1], valid for both ideal and nonideal plasmas. Here we apply these results to determine the effect of a few individual surrounding ions on the dense plasma electron states and, in particular, on the electron state collectivization by tunneling. Validity of the transient diatomic quasimolecule model, found in literature, is discussed. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coherent collisional absorption in clustered media
Authors: Mulser P.
Published: October 2003

In a clustered medium the deflections of an electron by the cluster ions superpose coherently, in this way acting as single ions of gigantic charge and hence leading to strongly increased inverse bremsstrahlung. Formulas for the absorption enhancement are presented and the main effects determining its efficiency are discussed. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mott effect and screening in quantum well structures
Authors: Reinholz H. , Röpke G.
Published: October 2003

We consider the formation of exciton bound states between electrons and holes in a 2D layer. The medium modifications of two‐particle properties are obtained froma systematic Green function approach within a cluster mean field approximation. Contributions from correlations (excitons) in the medium are given. The importance of Pauli blocking on the shift of the ionization energy of excitons in comparison to screening is shown. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Negative friction in dusty plasmas
Authors: Trigger S.A. , Zagorodny A.G.
Published: October 2003

Within the approximation of dominant charging collisions the explicit microscopic calculations of the Fokker‐Planck kinetic coefficients for highly‐charged grains moving in plasma are performed. It is shown that due to ion absorption by grain the collecting friction coefficient can be negative and the appropriate threshold value of the grain charge is found. The stationary solutions of the Fokker‐Planck equation with the velocity dependent kinetic coefficient are obtained and the considerable deviation of such solutions from the Maxwellian distribution is established. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermal benefit of sibling presence in the newborn rabbit
Authors: Bautista A. , Drummond H. , Martínez‐Gómez M. , Hudson R.
Published: October 2003

Newborn rabbits compete vigorously for the mother's milk, and survivors benefit from littermate deaths. Here we report that rabbit pups also may benefit from littermate presence in terms of increased thermal efficiency. Pups nursed normally once a day by their mother but otherwise raised alone had a lower probability of survival, lower body temperature, and lower efficiency of converting milk into body mass than their siblings raised with littermates. The contribution of a more favorable thermal environment to the better growth and survival of group‐raised pups was supported by the finding that single pups raised at higher ambient temperatures grew more rapidly than single pups raised at lower temperatures. These effects were most clearly seen across Days 2 to 5, after which time differences between treatment groups were no longer significant. Thus, the results of this study suggest that the benefits as well as costs of having siblings must be weighed against each other when considering the manner in which sibling presence influences individual development and survival. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 208–215, 2003.
Pricing recreation use of national parks for more efficient nature conservation: an application to the Portuguese case
Authors: Mendes Isabel
Published: October 2003

This paper considers under what theoretical conditions, based on utilitarian, individual preferences, an entrance fee can be applied to some national parks before clarifying the sustainable effects of this instrument when used for conservation. The fee is discussed in terms of efficiency and equity following on from conclusions of previous theoretical reviewing, and a travel cost empirical approach is further used to estimate one for a Portuguese national park. We conclude that entrance fees are efficient only if parks have positive recreation costs and if fee system administration costs are low. Any efficient fee must be set equal to the marginal costs of supplying the park for recreation where these costs are known and below current recreation demand, or to the marginal recreation benefit of each visitor where they are unknown and/or above the current recreation demand curve. Finally, characteristics of outdoor recreation demand require the adoption of differential entrance fee schemes given revenue and equity issues. Copyright © 2003 John Wiley & Sons, Ltd and ERP Environment.
A Novel PVC‐Membrane‐Coated Graphite Sensor Based on an Anthraquinone Derivative Membrane for the Determination of Lead
Authors: Riahi S. , Mousavi M. F. , Shamsipur M. , Sharghi H.
Published: October 2003

A highly selective membrane electrode for the determination of ultratrace amounts of lead was prepared. The PVC membrane electrode based on 2‐(2‐ethanoloxymethyl)‐1‐hydroxy‐9,10‐anthraquinone (AQ), directly coated on graphite, exhibits a good Nernstian response for Pb(II) ions over a very wide concentration range (1.0×10−7–1.0×10−2 M) with a limit of detection of 8.0×10−8 M. It has a fast response time of ca. 10 s and can be used over a period 2 months with good reproducibility (SD=±0.2 mV). The electrode revealed a very good selectivity respect to common alkali, alkaline earth, transition and heavy metal ions and could be used in the pH range of 3.5–6.8. It was used as an indicator electrode in potentiometric titration of lead ions with chromate and oxalate, and in indirect determination of lead in spring water samples.
Nonmonotonic Transient Potential Signals with an 18‐Crown‐6 based Ion‐Selective Electrode in a Flow‐Injection System
Authors: Ortuño Joaquín A. , Sánchez‐Pedreño Concepción , Martinez Domingo
Published: October 2003

The dynamic potential response of an 18‐crown‐6 based ion‐selective electrode towards Li+, Na+, K+ and Ca2+, in a flow‐injection system is studied. Different double nonmonotonic transient signals are obtained for the different ions. The influence of the flow‐injection variables and of ion concentration on the signals is studied. Two signal parameters, the relative return rates, are found to be characteristic for each ion and are constant for a concentration range of 1–3 decades. The nonmomotonic transient signals obtained are explained by reference to the theoretical models reported.
Electrochemical Oxidation of 8‐Oxo‐2′‐Deoxyguanosine on Glassy Carbon, Gold, Platinum and Tin(IV) Oxide Electrodes
Authors: Langmaier Jan , Samec Zdeněk , Samcová Eva
Published: October 2003

Cyclic voltammetry was used to investigate the oxidation of 8‐oxo‐2′‐deoxyguanosine (8‐oxo‐dG) on the glassy carbon (GC), platinum, gold and SnO2 electrodes over a range of the sweep rate, 8‐oxo‐dG concentration and the solution pH. Reaction mechanism that is common to all these electrodes involves the two‐electron two‐proton charge transfer step followed by the irreversible chemical reaction(s). Rate of the charge transfer reaction decreases with the increasing solution pH (GC, Pt, Au), and depends on the nature of the electrode material following the sequence GC>Pt, Au>>SnO2. These effects can be related to the degree of oxidation of the electrode surface (Pt, Au, SnO2), or to the density of the active surface sites (GC). Any of these electrodes can be used for the fabrication of an amperometric detector for 8‐oxo‐dG .
A New Polyphenol Oxidase Biosensor Mediated by Azure B in Laponite Clay Matrix
Authors: Shan Dan , Mousty Christine , Cosnier Serge , Mu Shaolin
Published: October 2003

Amperometric biosensor based on the entrapment of polyphenol oxidase within a laponite clay coating and cross‐linked by glutaraldehyde is described for catechol detection. Laponite provides a hydrophilic enzyme surrounding increasing the long term stability of the biosensor compared to the corresponding biosensors obtained by chemical cross‐linking of PPO with glutaraldehyde. Azure B, a cationic dye exchanged within the clay matrix, is used as an electron shuttle allowing the mediated detection of phenol derivatives at −0.05 V. The detection limits obtained with the optimized biosensor configuration for catechol, p‐cresol and phenol are 1, 1 and 17 nM, respectively.
The Electrochemical Oxidation of 5‐Thio‐2‐nitrobenzoic acid (TNBA) at a Boron Doped Diamond Electrode: Demonstration of a CEC Reaction
Authors: Nekrassova Olga , Lawrence Nathan S. , Compton Richard G.
Published: October 2003

The oxidation of 5‐thio‐2‐nitrobenzoic acid (TNBA) over a wide pH range has been investigated using cyclic voltammetry at a boron doped diamond electrode. The reaction has been shown to proceed via a CEC reaction process in which at lower pH the thiol moiety of the TNBA species has to undergo deprotonation before oxidation. DIGISIM modelling of the voltammetric profiles deduced a value of 5.2 for the pKa of the thiol moiety which is in good agreement with that obtained from spectrophotometric data. Also reported are the rate constants for all the heterogeneous and homogeneous processes.
Shape of “True” transition boiling curve and two‐mode boiling
Authors: Lee Duu‐Jong , Mei Lu Shaw
Published: October 2003

Two‐mode boiling could occur on the same heating element, which provided information on the criterion separating the stable and metastable boiling regimes. The “equal‐area” criterion based on the complete boiling curve interpreted the criterion of coexistence of the two boiling modes. However, the transition boiling curve could not be constructed by the pool boiling tests. Literature works adopted various correlations of transition boiling curves for analysis, but failed to recognize the possible errors incorporated in such an approximation. This paper demonstrated the relative errors embedded in calculating the equal‐area criterion by assuming various shapes of the transition boiling curve. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(7): 593–601, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10113
A numerical study of combined forced and natural convection heat transfer in a vertical cylinder bundle
Authors: Inoue Ken , Hattori Naozo
Published: October 2003

Combined forced and natural convection in a bundle of vertical cylinders have been studied numerically with the aid of Riemann geometry. The cylinders heated uniformly are arranged in an equilateral triangular pattern of three bundle spacings S/D = 1.1, 1.5, and 1.9. Numerical calculations are made of the mixed convection of air (Pr = 0.7) in a subchannel of the bundle at ratios of modified Grashof number to Reynolds number Gr*/Re from 1 to 105. The results show that the reverse flows appear along the center line in the subchannel with increasing Gr*/Re. Local Nusselt numbers for the thermally fully‐developed region are well correlated with Gr*/Re. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(7): 639–649, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10118
Non‐viral human IL‐10 gene expression reduces acute rejection in heterotopic auxiliary liver transplantation in rats
Authors: Hong In Chul , Mullen Patricia M. , Precht Andrew F. , Khanna Ajai , Li Melissa , Behling Cynthia , Lopez Valerie F. , Chiou Henry C. , Moss Ronald B. , Hart Marquis E.
Published: October 2003

We studied nonviral delivery, expression, and the effect of the human interleukin‐10 (Hu IL‐10) gene on the rat model of heterotopic auxiliary liver transplantation (HALT). Two previous pilot studies showed remarkable expression of the Hu IL‐10 gene in donor and recipient rats, and a decreasing effect of acute rejection in certain cases. In this study, we focused on the efficacy of Hu IL‐10 gene expression to decrease acute rejection compared with cyclosporine A (CyA) in a HALT model. Three study groups and one control group were designed. Each group consisted of 6 DA donor and 6 Lewis recipient rats, which underwent HALT. In the control group, donors and recipients were not treated at all. In group II, recipients were treated with one dose of CyA. In group III, donors were treated with Hu IL‐10 plasmid. In group IV, donors were treated with Hu IL‐10 plasmid, and recipients were treated with one dose of CyA. Rejection was established by histopathology: it revealed 100% rejection in control and 33.3% rejection in study groups II, III, and IV. Human IL‐10 gene expression prevented acute rejection with the same efficacy as CyA in the HALT model in rats. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:432–436 2003
Charge injection into disordered molecular films
Authors: Burin Alexander L. , Ratner Mark A.
Published: October 2003

Light‐emitting devices made by organic or inorganic dielectric films placed between two metal electrodes emit light because of the radiative recombination of positive and negative charge carriers entering the dielectric from the anode and cathode sides, respectively, under applied voltage. Standard vapor‐deposition technology of the device construction suggests the remarkable disordering at the metal dielectric interface and in the structure of dielectric film. The structural imperfections strongly affect carrier injection and transport, device efficiency, performance, and stability. In this article we describe the effect of disordering on the injection current through the dielectric layer and discuss the implications for the device performance. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2601–2621, 2003
Synthesis and electrochromic properties of a new family of methacrylate polymers containing pendant oligothiophenes
Authors: Ohsedo Yutaka , Imae Ichiro , Shirota Yasuhiko
Published: October 2003

A new family of methacrylate polymers containing pendant terthiophene, quaterthiophene, quinquethiophene, and sexithiophene was synthesized by the radical polymerization of the corresponding methacrylate monomers, and the electrochemical and electrochromic properties were investigated. The anodic oxidation of these polymers in the presence of tetra‐n‐butylammonium perchlorate as a supporting electrolyte produced radical‐cation salts of pendant oligothiophenes with ClO as a dopant. The electrochemically oxidized polymers had partially crosslinked structures resulting from the coupling reaction of pendant oligothiophene radical cations, the extent of crosslinking significantly decreasing with the increasing conjugation length of the pendant oligothiophenes. Comparative spectroelectrochemical studies of the monomers in solution and the polymers as solid films showed that π‐dimer formation of oligothiophene radical cations took place more readily for the polymer films than for the monomers in solution. This new family of methacrylate polymers containing pendant oligothiophenes constitutes a new class of potential electrochromic materials, undergoing reversible, clear color changes on electrochemical oxidation and reduction. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2471–2484, 2003
Electronic injection and conduction processes for polymer devices
Authors: Braun David
Published: October 2003

This article summarizes mechanisms considered to explain electronic transport in organic and polymer devices, primarily light‐emitting diodes. Four tables summarize models on the basis of thermal processes such as thermionic and field emission, a variety of tunneling paths, hopping, space‐charge‐limited models, and several field‐dependent mobility models. Energy‐band diagrams illustrate and compare selected models. This article catalogs the mechanisms in an effort to easily direct readers to the relevant literature for more detailed treatments. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2622–2629, 2003
Magnetism of small Mn clusters
Authors: Guevara Javier , María Llois Ana , Aguilera‐Granja F. , Montejano‐Carrizales J. M.
Published: October 2003

The role of structure on the magnetic properties of Mn clusters is investigated by performing calculations for different growth families, icosahedral, bcc and fcc. The spin‐polarized electronic properties of these geometries are calculated by solving an spd tight‐binding Hubbard‐like Hamiltonian in the unrestricted Hartree–Fock approximation by using a bulk‐like parametrization, extra orbitals of s‐like character being added to take into account spillover effects present in transition metal clusters. Conclusions about the possible structure of these clusters as a function of size are drawn by comparison with recent experimental results. We find that for small clusters the preferred structure is mainly icosahedral while for larger sizes (N ≥ 30) the bcc structure begins to compete with the icosahedral one. The magnetic coupling within the clusters is non‐ferromagnetic.
Confinement‐, surface‐ and disorder‐related effects in the resonant Raman spectra of nanometric CdS1−xSex crystals
Authors: Gomonnai A. V. , Azhniuk Yu. M. , Yukhymchuk V. O. , Kranjčec M. , Lopushansky V. V.
Published: October 2003

The Raman spectra of CdS1−xSex nanocrystals, embedded in a borosilicate glass matrix, are studied, CdS‐like and CdSe‐like LO phonon frequencies being used to determine the nanocrystal composition. The Raman lineshape is analyzed taking account of confinement‐related phonons with nonzero wavevector, surface phonon modes, glass matrix pressure and disorder effects.
Electron irradiation‐induced electro‐migration and diffusion of defects in Mg‐doped GaN
Authors: Gelhausen O. , Klein H. N. , Phillips M. R. , Goldys E. M.
Published: October 2003

In‐plane‐ and depth‐resolved cathodoluminescence (CL) microanalysis and spectroscopy was carried out to study the impact of electron injection on electro‐migration and diffusion of native defects and residual impurities in rapidly thermally annealed (RTA) Mg‐doped p‐type GaN. During intense electron beam irradiation (e.g. Eb = 10 keV, Ib = 80 nA), an electric field is generated within the primary beam interaction volume. We observed the following two electric field‐related effects: (i) an increased electron recombination length and a subsequent field‐assisted charge spreading, which causes a dissociation of Mg–H complexes beyond the interaction volume of the primary electron beam, and ii) thermally assisted electro‐migration of positively charged, mobile defects leading to the formation of deeper complexes, which are highly stable and act as nonradiative recombination pathways. Furthermore, the diffusion of electron beam‐dissociated hydrogen was found to result in the passivation of Mg acceptors beyond the charge recombination volume.
Prospects for carrier‐mediated ferromagnetism in GaN
Authors: Graf Tobias , Goennenwein Sebastian T. B. , Brandt Martin S.
Published: October 2003

Room‐temperature ferromagnetism has been theoretically predicted for Mn‐doped GaN, making this material promising for spintronic applications. The cover figure shows the defect molecule picture for Mn3+‐induced gap states, which are derived from the antibonding transition‐metal t2↑ orbitals and the dangling bond t2↑↓ states of the host lattice. One of the d‐like Mn3+ t2↑ levels is occupied by a hole. These localized spins together with free valence‐band holes mediate the magnetic coupling, resulting in a very high Curie temperature.

The first author of the Feature Article [1], Tobias Graf, has been working on electrically detected magnetic resonance of III–V alloys, at the Walter Schottky Institut of TU München.
The rehabilitation of unilateral neglect: a review of the
evidence
Authors: Bowen Audrey , Wenman Rachel
Published: October 2003

Unilateral spatial neglect is a disorder that has, for many years,
intrigued and frustrated researchers and clinicians working in the area of
stroke rehabilitation. A vast literature exists on the subject of neglect, much
of it published by neuropsychologists and neurologists. Many of these papers
aim to identify the underlying causal mechanisms, in terms of the
neuroanatomical structures and cognitive processes involved. More recently,
research has focused on evaluation of rehabilitation strategies to reduce the
disabling effects of neglect. Various research designs have been used to
examine whether a particular approach is effective or not. These range from
single-case experimental designs (where the individual acts as their own
control) through to randomized controlled trials (RCTs). In the latter,
comparisons are made between (typically) two groups, one randomly assigned to
receive the therapy approach under investigation and the other assigned to the
control treatment.
Surface forcing on the southern flank of Georges Bank, February–August 1995
Authors: Beardsley Robert C. , Lentz Steven J. , Weller Robert A. , Limeburner Richard , Irish James D. , Edson James B.
Published: October 2003

Surface wind stress, heat, and freshwater fluxes were estimated over the southern flank of Georges Bank during February–August 1995 using moored measurements made at ST1 located on the 76‐m isobath, roughly halfway between the tidal mixing and shelf/slope fronts. Wind stress variability was dominated by a succession of atmospheric lows that passed Georges Bank during the deployment. A transition between frequent lows and strong wind stress events (“winter”) to less frequent lows and weaker wind stresses (“summer”) occurred in mid‐May. In winter, wind stress fluctuations tended to be omnidirectional, with maximum stresses above 0.5 N/m2 during four storms, one a classic “nor'easter”, while summer fluctuations were weaker but strongly polarized in the along‐bank direction. The ST1 surface heat flux was dominated by shortwave heating, which increased from a winter mean of 130 W/m2 to 230 W/m2 in summer. Long‐wave cooling decreased from 50 W/m2 (winter) to 30 W/m2 (summer), while mean sensible and latent fluxes increased from −20 and −40 W/m2 (winter) to +10 and 0 (summer) respectively. Overall, winter was characterized by weak net heating (30 W/m2) with shortwave gain offset by long‐wave, latent, and sensible heat loss. In summer, increased shortwave gain and reduced long‐wave loss and weak sensible and latent fluxes combined to produce strong net heating (210 W/m2). ST1 precipitation was highly episodic with little seasonality while evaporation occurred mostly during winter, resulting in a net evaporation of −15 cm and net freshwater flux of +48 cm over the deployment.
Quantification of carbon sequestration in soils following pasture to forest conversion in northwestern Ecuador
Authors: de Koning G. H. J. , Veldkamp E. , López‐Ulloa M.
Published: October 2003

We studied the changes in soil carbon contents when pastures are converted to either secondary forest or plantation forest in north‐western Ecuador. At 40 sites within the region, paired pasture and forest plots were compared. We related the observed soil carbon concentrations, stocks, and changes (in the 0–0.25 m and 0.25–0.5 m layers) to land use history, climate, and soil characteristics. Variation in carbon concentrations over sites in volcanic soils could be well predicted for both pastures (R2 = 0.96) and forests (R2 = 0.93) on the basis of soil mineralogy, while for sedimentary soils, clearly less variation could be explained (R2 = 0.14 for pastures and 0.39 for forests). The dominant factor explaining changes in carbon stocks following pasture to forest conversion was pasture age. Forests, paired with pastures less than 10 years old, had on average 9.3 Mg ha−1 less soil carbon than the pastures, while forests paired with pastures between 20 and 30 years old had on average 18.8 Mg ha−1 more soil carbon and forest paired with pastures older than 30 years had on average 15.8 Mg ha−1 more carbon than the pastures. In this region, reforestation of old pastures will generally lead to an increase of soil carbon stocks. These results can be used for optimal site selection for carbon sequestration projects and for including soil carbon in the estimated benefits of these projects.
Height profile of particle concentration in an aeolian saltating cloud: A wind tunnel investigation by PIV MSD
Authors: Dong Zhibao , Wang Hongtao , Zhang Xiaohang , Ayrault Michael
Published: October 2003

Attempt is made to define the particle concentration in an aeolian saltating cloud and its variation with height using artificial spherical quartz sand in a wind tunnel. The height profiles of the relative particle concentration in aeolian saltating cloud at three wind velocities were detected by the state of the art PIV (Particle Image Velocimetry) MSD (Mie Scattering Diffusion) technique, and converted to actual concentration based on sand transport rate and the variation with height of velocity of the saltating cloud. The particle concentration was found to decay exponentially with height and to increase with wind velocity. It decayed more rapidly when the wind velocity decreased. The volume/volume concentration in the near‐surface layer was at the order of 10−4. The results obtained by PIV MSD technique were in good agreement with those derived from the sand flux and velocity profiles, the former being about 15% greater than the later.
Multiple‐event relocation of historic earthquakes along Blanco Transform Fault Zone, NE Pacific
Authors: Cronin Vincent S. , Sverdrup Keith A.
Published: October 2003

Blanco Transform Fault Zone (BTFZ) is part of the Juan de Fuca Ridge system located ∼200–500 km west of the Oregon coastline. Individually located epicenters reported by the International Seismological Center (ISC) and National Earthquake Information Center along the BTFZ are not well correlated spatially with the active transform boundary. More accurate locations of 120 mb ≥ 5.0 earthquakes relative to each other have been obtained using a joint‐relocation process that yields improved epicenter locations relative to each other. Six of these earthquakes have been independently located using data from the U.S. Navy's SOSUS hydrophone array, enabling specification of a static correction to improve absolute locations for all 120 relocated epicenters relative to the BTFZ. The final locations average ∼34.6 ± 15.2 km toward azimuth 196° ± 28° relative to the original ISC locations. The 95% confidence ellipses of most of the relocated epicenters fall on or very near active structural features along the BTFZ.
Numerical modelling of the growth dynamics of a simple silicic lava dome
Authors: Hale A. J. , Wadge G.
Published: October 2003

Two‐dimensional axisymmetrical computational models have been developed using finite element techniques to represent the rheological stiffening due to degassing‐induced crystallisation and the effects of a brittle carapace within a simple lava dome. The dome is modelled numerically considering the effects of temperature, pressure and rate of extrusion. Using these state variables the bulk viscosity is derived from empirical equations and the bulk rheology approximated using a solidification viscosity, dividing the dome into solid‐dominated and fluid‐dominated domains. Elastoplastic equations for the solid component and fluid‐mechanical equations for the fluid domain are solved simultaneously allowing continuous stress across the fluid‐solid interface to ensure the two components move in unison. We apply this model, a Hookean solid carapace model and a purely fluid lava dome model to the case of the October 1980 lava dome at Mount St. Helens. The results show that dynamic growth models involving a solid carapace are required to simulate this lava dome.
Germanium/silicon ratios in the Copper River Basin, Alaska: Weathering and partitioning in periglacial versus glacial environments
Authors: Anders Alison M. , Sletten Ronald S. , Derry Louis A. , Hallet Bernard
Published: October 2003

Glacial to interglacial variation in the germanium to silicon ratio (Ge/Si) of biogenic opal in oceanic sediment cores has been proposed to record terrestrial silicate weathering intensity. However, data connecting Ge/Si ratios to weathering are sparse, especially for cold regions. To characterize Ge/Si of the dissolved loads of rivers draining modern glacial and periglacial regions, we measured Ge and major element chemistry of more than 30 streams in the Copper River Basin of south Alaska. We measured significantly higher Ge/Si in rivers with greater than 15% glacial cover in their basins than in rivers draining areas with less glacial cover, which we attribute to preferencial subglacial weathering of biotite. We also ran laboratory experiments to investigate the role of differential sorption of Ge and Si on hydrous iron oxides in moderating the Ge/Si ratio of rivers in recently deglaciated basins. These experiments indicate that Ge is preferentially adsorbed over Si by hydrous iron oxides over a wide range of pH values and support differential sorption as a potentially significant fractionation process. Our measured high Ge/Si in glaciated basins is in striking contrast to the low Ge/Si in the oceanic record during glacial periods. The glacial to interglacial changes in marine Ge/Si cannot simply reflect changes in glacier cover on land, as the mineralogy of silicates weathered and processes partitioning Ge in soils must also strongly influence the fluvial Ge and Si inputs to the ocean.