bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum mechanical calculation of the OH+HCl→H2O+Cl reaction rate: Full-dimensional accurate, centrifugal sudden, and J-shifting results
Authors: Huarte-Larrañaga Fermı́n , Manthe Uwe
Published: April 2003

Full-dimensional quantum calculations for the thermal rate constant of the OH+HCl→H2O+Cl reaction rigorously accounting for the total angular momentum are presented in this work. The dynamics calculation is performed on the Clary, Hernández, and Nyman potential energy surface and employs the flux correlation function formalism and the multiconfigurational time-dependent Hartree scheme. Comparison of the theoretical k(T) values with experiment reveals deficiencies of the potential energy surface. In order to test the validity of different approximations often imposed on the overall rotation, quantum dynamics simulations have also been carried out within the coupled states (CS) and J-shifting approximations. No significant discrepancies are found between CS and accurate results as was to be expected from previous experience. In contrast to previous results for the OH+H2 reaction, the J-shifting approximation yields a reasonable agreement as well.
Temperature-dependent rotational relaxation in a viscous alkane: Interplay of shape factor and boundary condition on molecular rotation
Authors: Dutt G. B. , Sachdeva A.
Published: April 2003

Rotational relaxation of three organic solutes, coumarin 6 (C6), 2,5-dimethyl-1, 4-dioxo3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP), and nile red (NR), that are similar in size but distinct in shape has been studied in a nonpolar solvent, squalane as a function of temperature to find out how the mechanical friction experienced by the solute molecule is influenced by its shape. It has been observed that C6 rotates slowest followed by NR and DMDPP. The results are analyzed using Stokes–Einstein–Debye (SED) hydrodynamic theory and also quasihydrodynamic theories of Gierer and Wirtz, and Dote, Kivelson, and Schwartz. Analysis of the data using the SED theory reveals that the measured reorientation times of C6 and DMDPP follow subslip behavior whereas those of NR are found to match slip predictions. While no single model could mimic the observed trend even in a qualitative manner, the reorientation times of C6 and DMDPP when normalized by their respective shape factors and boundary-condition parameters can be scaled on a common curve over the entire range of temperature studied. The probable reasons for the distinctive rotational behavior of NR as compared to C6 and DMDPP are explained in terms of its molecular shape and how this in turn influences the boundary-condition parameter are discussed.
Analysis of turbulent-transport suppression in non-neutral plasmas by turbulence theory based on mass-weighted averaging
Authors: Yoshizawa Akira , Yokoi Nobumitsu
Published: April 2003

Turbulent-transport suppression is investigated on the basis of the turbulence theory founded on the mass-weighted averaging. Effects of plasma non-neutrality occur twofold. One is a direct electric-field effect, and the other is an indirect effect through the E×B flow. The results are discussed in light of transport barriers in tokamaks. Specifically, it is shown that the electric-field curvature and the bulk poloidal flow generating a centripetal force contribute to the suppression of turbulence and heat transport, but that the shear part of the flow leads to the enhancement of turbulence.
Atomic diffraction study of the interaction of helium atoms with the surface of an organic single crystal: The (001) cleavage planes of guanidinium methanesulfonate
Authors: Bracco Gianangelo , Ward Michael D. , Scoles Giacinto
Published: April 2003

The guanidinium methanesulfonate is a layered self-assembled organic crystal which presents a bilayer structure and two different (001) planes can be exposed upon cleavage. In a previous paper we have shown that the analysis of the rate of decay in the thermal attenuation of the diffraction intensities in the scattering from the (001) surface of single crystal guanidinium methanesulfonate allows for distinguishing between the two possible (001) cleavage planes. However, since a more detailed knowledge of the He-surface interaction was lacking, in this paper we complete the investigation by studying the attractive part of the interaction potential between He and the surface terminated by methyl groups projecting outward from the hydrogen bonded sulfonate and guanidinium sheets. Four bound state levels have been determined and a well depth D=(6.7±0.2) meV has been estimated.
Sufficient condition for the stability of rotating plasmas
Authors: Badin V. I.
Published: April 2003

The infinitesimal stability of the differential rotation of cold homogeneous collisionless plasmas is examined using the hydrodynamic equations. A sufficient condition for the stability with respect to two-dimensional perturbations is obtained via the general Lyapunov approach and compared with similar conditions for the stability of fluids.
Kinetic ballooning stability of internal transport barriers in tokamaks
Authors: Hirose A. , Elia M.
Published: April 2003

Steep plasma pressure gradient can be stably sustained in tokamaks if the magnetic shear s is weak, either positive or negative. A fully kinetic integral equation code has been developed to investigate stability of the drift and ballooning modes in tokamaks. For small shear |s|≪1 where the magnetohydrodynamic ballooning mode is known to be stable, the kinetic ballooning mode is stable only if the pressure gradient exceeds a threshold.
The use of Simmons’ equation to quantify the insulating barrier parameters in Al/AlOx/Al tunnel junctions
Authors: Dorneles L. S. , Schaefer D. M. , Carara M. , Schelp L. F.
Published: April 2003

We have analyzed the electron transport processes in Al/AlOx/Al junctions. The samples were produced by glow-discharge-assisted oxidation of the bottom electrode. The nonlinear I–V curves of 17 samples were measured at room temperature, being very well fitted using the Simmons’ equation with the insulating barrier thickness, barrier height, and the junction area as free parameters. An exponential growth of the area normalized electrical resistance with thickness is obtained, using just values from I–V curve simulations. The effective tunneling area corresponding to the “hot spots” can be quantified and is five orders of magnitude smaller than the physical area in the studied samples.
Investigation of degradation for ohmic performance of oxidized Au/Ni/Mg-doped GaN
Authors: Lin Yow-Jon , Li Zhen-Dao , Hsu Chou-Wei , Chien Feng-Tso , Lee Ching-Ting , Shao Sheng-Tien , Chang Hsing-Cheng
Published: April 2003

The mechanism of ohmic contact degradation for the oxidized Au/Ni/Mg-doped GaN under various annealing times has been investigated. According to the results from x-ray photoelectron spectroscopy and the Cserveny’s concept, we found that an increase of hole concentration of NiOx would lead to the increasing barrier height and the increasing specific contact resistance (ρc) of oxidized Au/Ni/Mg-doped GaN. This suggests that the NiOx plays an important role in increasing (or reducing) the ρc of oxidized Au/Ni/Mg-doped GaN.
Interfacial reaction during the epitaxial growth of yttrium on CaF2(111)
Authors: Borgschulte A. , Weber S. , Schoenes J.
Published: April 2003

By means of Auger electron spectroscopy and in situ reflection high-energy electron diffraction (RHEED) the interfacial reaction during the epitaxial growth of yttrium on CaF2(111) has been studied. The RHEED patterns confirm a smooth Volmer–Weber growth mode. Auger electron spectroscopy evidences a strong interdiffusion of the film and substrate, leading to a compressive in-plane strain of the growing film. Using RHEED, we can follow the strain relaxation via misfit glides during growth. The development and crystalline orientation of the glides are characterized.
Frequency multiplication of microwave radiation by propagating space-charge domains in a semiconductor superlattice
Authors: Scheuerer R. , Haeussler M. , Renk K. F. , Schomburg E. , Koschurinov Yu. I. , Pavelev D. G. , Maleev N. , Ustinov V. , Zhukov A.
Published: April 2003

We report on frequency multiplication of microwave radiation by propagating space-charge domains in a semiconductor superlattice; the domains were due to a negative differential mobility of miniband electrons. We irradiated an arrangement of two GaAs/AlAs superlattices, mounted in a rectangular waveguide system, with microwave radiation (frequency near 70 GHz) and observed the generation of harmonics; the conversion of radiation power to the third harmonic showed a remarkable efficiency (5%). A theoretical study, based on a drift-diffusion model for the miniband electrons, suggests that the microwave radiation has driven the formation and annihilation of space-charge domains and that the resulting anharmonic current was the source of the frequency-multiplied radiation. Our results indicate that frequency multiplication by space-charge domains in a semiconductor superlattice can be exploited for efficient generation of submillimeter-wave radiation.
Evidence of electronic phase separation in Er3+-doped La0.8Sr0.2MnO3
Authors: Ravindranath V. , Rao M. S. Ramachandra , Suryanarayanan R. , Rangarajan G.
Published: April 2003

Er 3+ doping at the La site in La0.8Sr0.2MnO3 showed an unusual increase in Curie/peak resistivity temperature (TC/TP) above a certain nominal dopant concentration (x⩾0.086). This increase is attributed to the presence of a cation-deficient ErMnO3 phase. Further, with increase in TP the overall resistivity of these compounds also decreases. We explain these results assuming the presence of a nanoscale mixture of charge-ordered antiferromagnetic insulating (CO-AFMI) phase in a ferromagnetic metallic matrix, wherein the increase in TC/TP with increase in Er3+ content is due to the local destruction of the CO-AFMI phase by the presence of the cation-deficient ErMnO3 phase. We thus provide an indirect evidence of electronic phase separation in these compounds.
Flat triode structure with a pulsed coplanar discharge channel representing similar features to a field-effect transistor
Authors: Sakai Osamu , Hashimoto Satoshi , Hatano Akitsugu
Published: April 2003

A completely flat configuration of three electrodes generates a regulated coplanar discharge in a pulse operation. The discharge current, flowing between one pair of electrodes, is monotonously controlled by the third electrode which keeps its isolation without any insulator layer. Current regulation mechanism is revealed by experimental and numerical analyses, which indicate that such a feature results from the mixed effects of electrode separation distance, gas pressure, and distortion of a three-dimensional potential profile.
Indirect excitation of Er3+ in sol-gel hybrid films doped with an erbium complex
Authors: Park Oun-Ho , Seo Se-Young , Bae Byeong-Soo , Shin Jung H.
Published: April 2003

Transparent sol-gel hybrid films doped with erbium tris 8-hydroxyquinoline were prepared using methyltriethoxysilane, vinyltriethoxysilane, and phenyltrimethoxysilane as precursors. We obtain a strong 1.53-μm Er3+ luminescence with a wide full width at half-maximum and no thermal quenching. Comparison of absorption of the film with the pump wavelength dependence of Er3+ luminescence intensity indicates the presence of an efficient indirect excitation path for Er3+ via organic ligands.
Turbine Blade Trailing Edge Flow Characteristics at High Subsonic Outlet Mach Number
Authors: Sieverding Claus H. , Richard Hugues , Desse Jean-Michel
Published: April 2003

The paper presents an experimental investigationof the effect of the trailing edge vortex shedding on the steady and unsteady trailing blade pressure distribution of a turbine blade at high subsonic Mach number M2,is=0.79 and high Reynolds number RE=2.8×106. The vortex formation and shedding process is visualized using a high-speed schlieren camera and a holographic interferometric density measuring technique. The blade is equipped with a rotatable trailing edge cylinder instrumented side-by-side with a pneumatic pressure tap and a fast response pressure sensor for detailed measurements of the trailing edge pressure distribution. The experiments demonstrate that contrary to the isobaric dead air region demonstrated at low subsonic Mach numbers the data reveal the existence of a highly nonuniform trailing edge pressure distribution with a strong pressure minimum at the center of the trailing edge. This finding is significant for the determination of the base pressure coefficient that is in general measured with a single pressure-sensing hole at the trailing edge center. The paper investigates further the effect of the vortex shedding on the blade rear suction side and discusses the superposition of unsteady effects emanating from the trailing edge and from the neighboring blade. The experimental data are a unique source for the validation of unsteady Navier-Stokes codes.
α-Heterosubstituted Aldehydes in Organic Synthesis. Enantioselective Approaches to New Analogues of Mevinic Acids
Authors: Enders Dieter , Burkamp Frank
Published: April 2003

Various aldol approaches towards the asymmetric synthesis of the lactone moiety of HMG-CoA-reductase inhibitors are described. Auxiliary controlled as well as catalytic aldol reactions resulted only in modest to low selectivities, whereas 1,2-additions to readily available highly enantiomerically enriched α-heterosubstituted aldehydes yielded δ-hydroxy-β-ketoesters with a high degree of diastereocontrol and in good chemical yields. The novel mevinic acid analogues could then be obtained bysyn-reduction of the addition products.
STABLE NON-BPS STATES IN STRING THEORY: A PEDAGOGICAL REVIEW
Authors: LERDA ALBERTO , RUSSO RODOLFO
Published: April 2003

We present a pedagogical review of the stable non-BPS states in string theory which have recently attracted some attention in the literature. In particular, following the analysis of A. Sen, we discuss in detail the case of the stable non-BPS D-particle of Type I theory whose existence is predicted (and required) by the heterotic/Type I duality. We show that this D-particle originates from an unstable bound state formed by a D1anti-D1 pair of Type IIB in which the tachyon field acquires a solitonic kink configuration. The mechanism of tachyon condensation is discussed first at a qualitative level and then with an exact conformal field theory analysis.
THE IMPACT OF NONLINEAR DYNAMICS IN THE ATMOSPHERIC SCIENCES
Authors: TSONIS A. A.
Published: April 2003

In this review some of the achievements in atmospheric sciences that resulted from chaos theory and its implications are discussed. They include El Niño dynamics, physics and spatiotemporal dynamics of the general circulation, and ensemble forecasting.
NONLINEAR OPTICAL PROPERTIES OFPbSNANOPARTICLES UNDER CW LASER ILLUMINATION
Authors: YU BAOLONG , GU YUZONG , MAO YANLI , ZHU CONGSHAN , GAN FUXI
Published: April 2003

The thermooptic coefficient dn/dT and the thermal-induced refractive index n2of PbS nanoparticles in organosol were measured. The optical limiting properties of PbS nanoparticles were studied under continuous wave (cw) laser illumination. The obtained results were analyzed and discussed.
BAND GAP RESONANT FEMTOSECOND PULSE PROPAGATION IN NONLINEAR DISPERSIVE SEMICONDUCTOR WAVEGUIDES
Authors: KUMAR ABHAY , SEN PRATIMA , SEN PRANAY K.
Published: April 2003

A detailed numerical analysis has been made for a femtosecond not-too-strong Gaussian pulse propagating through a millimeter size GaAs waveguide. The role of weakly bound 1s-excitonic structure below the fundamental absorption edge has been incorporated in the time dependent perturbation treatment of the coherent pulse-semiconductor interaction. The analysis reveals the occurrence of both self-steepening and spectral broadening arising due to the inherent intensity dependence of the complex optical susceptibility in GaAs waveguide structures.
TENDINOSIS OF THE ROTATOR CUFF: A REVIEW
Authors: Rosa Tammy L. Dela , Wang Allan W. , Zheng Ming H.
Published: April 2003

Rotator cuff tendinosis is a disease whose etiology and pathophysiology are still under debate. Three mechanisms have been proposed as giving rise to rotator cuff disease: the intrinsic mechanism, the extrinsic mechanism and overuse. Evidence for and against each one as being the primary cause of disease abounds. The current consensus is that the etiology is probably multifactorial and each factor plays different roles in different patients. The histologic features of rotator cuff disease are fibroblast hyperplasia, collagen disorganization and neovascularization. These findings together are termed angiofibroblastic hyperplasia, believed to be a reflection of unsuccessful attempts at repair of tendon with a tendency towards degeneration. The concept supports the current view that rotator cuff disease is a tendinosis, a degenerative process, rather than a tendinitis, an inflammatory one. This poor healing response is seen in the collagen content of diseased tendon. Production of collagen fails to shift from the initial type III collagen to the mature type I collagen, causing the tendon to become weak. Most current treatment modalities fail to address the biologic processes going on within the tendon and future directions need to address these problems.
Prenatal Imaging of Congenital Cerebral Primitive Neuroectodermal Tumor
Authors: Yamada Takashi , Takeuchi Kyousuke , Masuda Yukiko , Moriyama Toshitake , Kitazawa Souhei , Maruo Takeshi
Published: April 2003

A case of fetal brain tumor, which appeared after 32 weeks’ gestation, is presented. Prenatal ultrasonography and magnetic resonance imaging demonstrated a large heterogeneous mass in the right supratentorial region and left enlarged ventricle. A male fetus weighing 2,616 g was delivered at 34 weeks’ gestation by cesarean section and died on the 37th day of life due to rapid growth of the tumor. Following autopsy, the pathohistological examination revealed primitive neuroectodermal tumor. Magnetic resonance imaging in the prenatal management of the congenital brain tumor is efficient in evaluating the expansion and margin of the tumor and intratumoral bleeding, which are not demonstrated by ultrasonography.
In utero Diagnosis of Bladder Perforation with Urinary Ascites
Authors: Löwenstein Lior , Solt Ido , Talmon Rafael , Pery Menucha , Suhov Polo , Drugan Arie
Published: April 2003

Prenatal sonographic diagnosis of fetal obstructive uropathy is relatively common. However, the complication of spontaneous rupture of the obstructed bladder in utero causing fetal urinary ascites is extremely rare. This case report describes an unusual case of congenital bladder perforation and urinary ascites diagnosed in utero. The pertinent literature is reviewed.
Caveats for the Use of Humerus Length in the Prediction of Fetal Down Syndrome
Authors: Vergani Patrizia , Locatelli Anna , Ghidini Alessandro , Mariani Eloisa , Strobelt Nicola , Biffi Anna , Pezzullo John C.
Published: April 2003

Objective: To assess the reliability and reproducibility of fetal humerus length in the diagnosis of trisomy 21. Methods: Cohort study inclusive of 22 trisomy 21 fetuses, who underwent ultrasonographic examination between 14 and 22 weeks’ gestation, and 457 euploid controls. Regression analysis was performed for humerus length as function of biparietal diameter. Based on the generated regression equation in euploid fetuses, expected values of humerus length for a given biparietal diameter were calculated. The ratios of observed to expected (O/E) humerus length values were compared between euploid and trisomy 21 fetuses using Student’s t test. Receiver operating characteristic (ROC) curve analysis was used to detect optimal thresholds of O/E humerus length for diagnosis of trisomy 21. In addition, a MEDLINE search was conducted for articles published on humerus length as predictor of trisomy 21. Results: No differences were present between the regression lines of trisomy 21 and euploid fetuses (mean ± standard deviation O/E humerus length in euploid and aneuploid fetuses: 1.00 ± 0.10 vs. 0.97 ± 0.11, p = 0.21). The optimal threshold O/E humerus length <0.88 identified by ROC curve analysis had a sensitivity of 18% and a false-positive rate of 9% for the diagnosis of trisomy 21. From a review of the evidence provided by the 17 published series on humerus length as predictor of Down syndrome, the following caveats emerge: (1) with a median false-positive rate of 5% (range 1–12%), the median sensitivity of humerus length was only 28% (range 15–64%); (2) differences were present among centers in the regression lines of euploid fetuses and in the optimal diagnostic thresholds of humerus length, suggesting inter-center variability, and (3) most populations studied were at high genetic risk for trisomy 21, hence the diagnostic ability of humerus length in low risk populations has not been tested. Conclusions: The ability of humerus length to predict trisomy 21 is inconsistent. Only institutions with locally generated regression equations and documented predictive ability of this marker should utilize humerus length as a screening test for trisomy 21, alone or incorporated into diagnostic algorithms with serum or other sonographic markers of trisomy 21. The diagnostic ability of humerus length in low risk populations is currently unknown.
Correlation and Overlapping between Nuchal Translucency and Triple Test among Down Syndrome-Affected Pregnancies
Authors: Herman Arie , Dreazen Eliezer , Tovbin Yosef , Reish Orit , Bukovsky Ian , Maymon Ron
Published: April 2003

Objectives: To examine the correlation and extent of overlapping between first-trimester nuchal translucency (NT) and second-trimester triple test (TT) results in Down syndrome (DS)-affected pregnancies. Methods: Results of both tests were obtained in 28 cases with DS. Inter-test correlation was performed by comparing the likelihood ratios (LRs). Screen-positive rates (risk >1:380) were calculated for different age groups by adjusting age-dependent background risk and tests’ LRs. Overlapping referred to ratio between screen-positive cases by both tests simultaneously and total screen-positive cases by either one or both tests. Results: No correlation was found between the tests’ LRs (Pearson correlation test, r = 0.0487). The overlapping between the tests was 25% and 38.5% among young patients of 20 and 35 years of age, respectively. The average overlapping among patients between 25 and 35 years of age was ∼33%. Only 3 of the 28 DS cases demonstrated LRs <1 by both tests and moreover none exhibited LRs <0.2 by both tests. Conclusions: The degree of overlapping of one third, between NT and TT, confirms the assumption that both tests utilized together improves DS detection. Screen- negative result, by both tests simultaneously, may reassure low-risk population and aid to reduce the number of non-indicated invasive tests.
The Risk of Radiation-Induced Carcinogenesis after External Beam Radiotherapy of Graves’ Orbitopathy
Authors: Akmansu Muge , Dirican Bahar , Bora Huseyin , Gurel Ozgur
Published: April 2003

Purpose: In order to estimate the risk of radiation-induced carcinogenesis after external beam radiotherapy of Graves’ orbitopathy, we made dosimetric measurements with thermoluminescent dosimeters in a male Rando phantom using our treatment technique. Methods: We produced dose-volume histograms from 5-mm CT slices using our treatment planning system. In this way we estimated the irradiation dose received by the main surrounding organs such as the brain, the bone and the eyeball. We use 6-MV X-ray for the treatment of Graves’ orbitopathy and our total dose is 2,000 cGy, 200 cGy per fraction. Clinical target volume was limited to the retrobulbar orbital content and medial rectus muscle, sparing the lenses, lacrimal glands and the sella turcica. All dosimetric measurements with thermoluminescent dosimeters were made 3 times. Results: We found that the dose to the right lens was 101.6 mGy and to left lens 103.4 mGy. Average absorbed doses to red bone marow, thyroid, lung, esophagus, bone surface, skin and brain, respectively, were estimated to be 523, 21, 4, 5, 81, 29, 47 mGy. Then, using tissue weighting factors specified by the International Commission of Radiation Protection, the resulting total effective dose was calculated to be 66.8 mSv. Conclusion: The risk factor for fatal cancer development derived from human epidemiological data is presently assumed to be 10% per Gy. In patients treated by our method of retro-orbital external beam radiotherapy for Graves’ orbitopathy, there is a 0.0067 (or 7 per 1,000 persons or 0.7%) risk of developing fatal radiation-induced cancer.
Psycholinguistic techniques in second language acquisition research
Authors: Marinis Theodore
Published: April 2003

This article presents the benefits of using online methodologies in second language acquisition (SLA) research. It provides a selection of online experiments that have been widely used in first and second language processing studies that are suitable for SLA research and most importantly discusses the hardware and software packages and other equipment required for the setting-up of a psycholinguistics laboratory, the advantages and disadvantages of the software packages available and what financial costs are involved. The aim of the article is to inspire researchers in second language acquisition to embark on research using online methodologies.
Costs and concentration of cancer care: evidence for pancreatic, oesophageal and gastric cancers in National Health Service hospitals
Authors: Bachmann Max , Peters Tim , Harvey Ian
Published: April 2003

Objectives: To examine relationships between the cost of hospital cancer care and the degree of specialisation of patients' doctors and hospitals as indicated by their annual case-loads.

Methods: Three cohorts comprising 2294 patients with cancers of the pancreas, oesophagus and stomach in 29 acute National Health Service (NHS) hospitals in south-west England and South Wales were followed prospectively for a year. For each patient, prognostic variables, service activity and survival data were recorded, and the hospital cost of cancer care and cost per year survived were estimated. Costs were estimated from quantities of resource units provided and a single set of unit costs. Costs per day survived after presentation to hospital were calculated as estimates of cost-effectiveness. Linear regression analyses examined the effects on total costs, and on costs per day survived of doctors' and hospitals' annual patient volumes, adjusting for prognostic variables and treatments.

Results: General ward care rather than specific treatments and investigations accounted for most of total costs. Costs per patient increased significantly with increasing doctor volumes. After adjustment for prognosis and treatments, however, cost-volume relationships were U-shaped, reflecting more active intervention by higher volume doctors, along with little activity and long stays among patients of lower volume doctors. Cost per day survived also had U-shaped relationships with doctor volumes. Regression models using continuous rather than categorical volume terms fitted the data best.

Conclusions: Doctors' specialisation is at least as important for efficiency and effectiveness as hospitals' specialisation. Cost and cost per day survived increased and then decreased with increasing doctor volumes, highlighting the need for critical attention to costs as services become highly specialised. Specialisation occurs along a continuum, with no clear volume threshold effects on survival or costs.
Development of a framework for knowledge translation: understanding user context
Authors: Jacobson Nora , Butterill Dale , Goering Paula
Published: April 2003

Objective: To develop a framework that researchers and other knowledge disseminators who are embarking on knowledge translation can use to increase their familiarity with the intended user groups.

Methods: The framework was derived from a review and analysis of the knowledge translation literature and from the authors' own experience with a variety of user groups.

Results: The framework consists of five domains: the user group, the issue, the research, the knowledge translation relationship, and dissemination strategies. Within each domain, the framework includes a series of questions. The questions provide the researcher with a way of organizing what he or she already knows about the user group and the knowledge translation project, of identifying what still is unknown, and of flagging what is important to learn.

Conclusions: Most researchers wishing to engage in knowledge translation are moving out of their own familiar contexts. By using this framework, researchers will learn about the new contexts in which they find themselves. The insights they gain will increase their familiarity with the user group, thus aiding in the implicit goal of the interactive model of knowledge translation: making the researcher a part of the user group context.
Pathways approaches to homelessness research
Authors: Clapham David
Published: April 2003

Research on homelessness has focused on either structural forces or individual actions or, where both are considered, has failed to find an effective way of analysing the two sets of factors together. This article looks at one way of doing this through the adoption of a ‘pathways’ framework. The article reviews existing pathways research on homelessness and argues that existing studies do not analyse the interaction of structural and action elements. A stronger theoretical framework is outlined and emphasis placed on the discourses which shape the nature of services for homeless people and the actions of both staff and homeless people themselves. Understanding of the interaction between these two groups is vital if the nature of homelessness is to be comprehended. A research method is needed which focuses on homelessness discourses and their restructuring and shaping through interaction in order that the aim of a holistic analysis can be achieved. Copyright © 2003 John Wiley & Sons, Ltd.
Homelessness in the US: an ethnographic look at consumption strategies
Authors: Hill Ronald Paul
Published: April 2003

This article provides an overview of scholarship on the lived consumption experience of homeless people in the US. Three ethnographic studies are the input for this integration, and the results are expressed thematically to be consistent with this methodological form. Internal dialogue from two short stories concerning single adult males and female‐headed families is used to make the themes come alive for the reader. The article concludes with a brief summary of these findings and implications for future homelessness research. Copyright © 2003 John Wiley & Sons, Ltd.
Chemischer Apparatebau im Aufbruch?
Authors: Weiß E. , Praus S. , Rudolph J. , Lietzmann A. , Mense T.
Published: April 2003

Die ACHEMA stellt eine eindrucksvolle Leistungsschau des Apparatebaus dar, die im engen Zusammenhang mit den epochalen Entwicklungen der Verfahrens‐ und Prozesstechnik steht. Dies ist ein günstiger Zeitpunkt, um über die Entwicklungschancen nachzudenken. Der Großanlagenbau hat in den letzten Jahrzehnten eine beträchtliche Korrektur erfahren, was sich besonders auf den deutschen Apparatebau ausgewirkt hat. Wirtschaftliche Zwänge lieferten einen zusätzlichen Anstoß für einen beachtlichen Schrumpfungsprozess. Der Apparatebau muss sich in der Zukunft auf zwei Standbeine konzentrieren: Hochqualifizierte Standardapparate und neuartige Produkte, die im engen Zusammenwirken mit der Verfahrenstechnik entwickelt werden müssen, um für neue Technologien und Prozessstrategien die erforderliche Hardware auf den Markt zu bringen. Der Beitrag nennt Gebiete, in denen sich der allgemeine technische Fortschritt manifestiert, aber auch aus der apparatetechnischen Sicht werden Anstöße vermittelt, wie ein gehobenes Qualitätsniveau der Produkte erreicht werden kann. Hierbei handelt es sich durchaus um Eigenschaften, die sich letztlich im wirtschaftlichen Ergebnis niederschlagen.
Parameterschätzung für nichtlineare dynamische Modelle auf Basis stark verrauschter, statistisch unvollständig bestimmter Messdaten
Authors: Heine T. , Kawohl M. , King R.
Published: April 2003

No abstracts.
Untersuchungen zum Aerosoltransport in Abscheidekammern für die Spektroskopie mit CFD und PIV
Authors: Budde C. , Schaldach G. , Razilov I. , Berndt H. , Werner U. , Walzel P.
Published: April 2003

No abstracts.
Umfassende Charakterisierung einer rußenden laminaren Methan‐Diffusionsflamme unter Nutzung verschiedener Lasermessverfahren
Authors: Seeger T. , Egermann J. , Dankers S. , Beyrau F. , Leipertz A.
Published: April 2003

No abstracts.
Integration offener Absorptionskreisprozesse zur kombinierten Wärmenutzung und Entfeuchtung in technologischen Systemen
Authors: Bittrich P. , Hebecker D.
Published: April 2003

No abstracts.
Lipase‐Catalysed Regioselective Acylations in Combination with Regioselective Glycosylations as a Strategy for the Synthesis of Oligosaccharides: Synthesis of a Series of Fucosyllactose Building Blocks
Authors: Rencurosi Anna , Poletti Laura , Russo Giovanni , Lay Luigi
Published: April 2003

A family of five regioisomeric protected fucosyllactoses has been synthesised in only 14 overall steps from the easily available benzyllactoside. The adopted strategy combines enzymatic regioselective protection, introduction of orthogonal protecting groups and regioselective glycosylations on partially unprotected lactosidic acceptors. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of Novel 4‐(2‐Oxoethylidene)azetidin‐2‐ones by a Lewis Acid Mediated Reaction of Acyldiazo Compounds
Authors: Cainelli Gianfranco , Giacomini Daria , Galletti Paola , Quintavalla Arianna
Published: April 2003

We report the synthesis of a class of 4‐(2‐oxoethylidene)azetidin‐2‐ones by a novel Lewis acid mediated reaction of acyldiazo compounds with 4‐acetoxyazetidin‐2‐ones. Using this approach, C‐3‐and C‐4‐substituted 4‐alkylideneazetidin‐2‐ones were obtained depending on the choice of starting azetidinone and α‐diazocarbonyl compound. The products reveal excellent Z diastereoselection of the C‐4 double bond. Variable amounts of E isomers are obtained depending on the nature of the C‐3 side chain, the Lewis acid, and the β‐lactam protection. VT NMR spectroscopic experiments and X‐ray structural analysis of crystalline derivatives demonstrate the presence of an intramolecular hydrogen bond in Z isomers, which drives the stereochemical outcome of the reaction. A possible mechanism for this novel reaction is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Risk selection and matching in performance‐based contracting
Authors: Lu Mingshan , Albert Ma Ching‐to , Yuan Lasheng
Published: April 2003

This paper examines selection and matching incentives of performance‐based contracting (PBC) in a model of patient heterogeneity, provider horizontal differentiation and asymmetric information. Treatment effectiveness is affected by the match between a patient's illness severity and a provider's treatment intensity. Before PBC, a provider's revenue is unrelated to treatment effectiveness; therefore, providers supply treatments even if their treatment intensities do not match with the patients' severities. Under PBC, budget allocation is positively related to treatment performance; patient–provider mismatch is reduced because patients are referred more often. Using data from the state of Maine, we show that PBC leads to more referrals and better match between illness severity and treatment intensity. Moreover, we find that PBC has a positive but insignificant effect on dumping. Copyright © 2002 John Wiley & Sons, Ltd.
Rigid‐body dynamics in the isothermal‐isobaric ensemble: A test on the accuracy and computational efficiency
Authors: Shinoda Wataru , Mikami Masuhiro
Published: April 2003

We have developed a time‐reversible rigid‐body (rRB) molecular dynamics algorithm in the isothermal‐isobaric (NPT) ensemble. The algorithm is an extension of rigid‐body dynamics [Matubayasi and Nakahara, J Chem Phys 1999, 110, 3291] to the NPT ensemble on the basis of non‐Hamiltonian statistical mechanics [Martyna, G. J. et al., J Chem Phys 1994, 101, 4177]. A series of MD simulations of water as well as fully hydrated lipid bilayer systems have been undertaken to investigate the accuracy and efficiency of the algorithm. The rRB algorithm was shown to be superior to the state‐of‐the‐art constraint‐dynamics algorithm SHAKE/RATTLE/ROLL, with respect to computational efficiency. However, it was revealed that both algorithms produced accurate trajectories of molecules in the NPT as well as NVT ensembles, as long as a reasonably short time step was used. A couple of multiple time‐step (MTS) integration schemes were also examined. The advantage of the rRB algorithm for computational efficiency increased when the MD simulation was carried out using MTS on parallel processing computer systems; total computer time for MTS‐MD of a lipid bilayer using 64 processors was reduced by about 40% using rRB instead of SHAKE/RATTLE/ROLL. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 920–930, 2003
The evolution of the concept of medicalization in the late twentieth century
Authors: Nye Robert A.
Published: April 2003

This article attempts to outline a history of the critique of medicalization that developed in the 1960s in the work of Thomas Szasz, R. D. Laing, Michael Foucault, and others that was applied in their work to medical and psychiatric theory and practice, the penal system, and public health systems. This article follows the development of Foucault's own work on “governmentality” that emphasized the individualization and internalization of the themes of medicalization and the application of these ideas by his disciples to contemporary medical developments. Finally, the author explores recent historiography in the history of medicine and public health that supports this thesis of individualization that both undermines and reconfigures the older notion of medicalization. © 2003 Wiley Periodicals, Inc.
Multiple‐point adsorption of terbium ions by lead ion templated thermosensitive gel: elucidating recognition of conformation in gel by terbium probe
Authors: Güney Orhan
Published: April 2003

Lead ion templated thermosensitive heteropolymer gel which has recognition ability of methacrylate pairs has been synthesized and characterized. The gel consists of a main monomer component, N‐isopropylacrylamide (NIPA), responsible for volume phase transition, methacrylic acid (MAA) moieties imprinted as pairs to adsorb terbium ions and cross‐links. An imprinting technique was applied using lead ion complex with methacrylate ligands in dioxane media. After gel was obtained, lead ions were removed by washing and the imprinted gel showed strong binding ability to terbium ions, comparable with that of the non‐imprinted gel prepared without lead ions. It was found that the Tb3+ fluorescence intensity was considerably increased upon binding this ion to both imprinted and non‐imprinted gels, but the largest enhancement of fluorescence intensity was observed when Tb3+ was bound to imprinted gel in shrunken state. This is because of the decrease of coordinated water molecules on Tb3+ and the strong binding of this ion to methacrylate pairs which are encoded within the weakly cross‐linked network of imprinted gel. Copyright © 2003 John Wiley & Sons, Ltd.
Canopy leaching of cations in Central European forest ecosystems – a regional assessment
Authors: Langusch Jens‐Johann , Borken Werner , Armbruster Martin , Dise Nancy B. , Matzner Egbert
Published: April 2003

The leaching of Ca, Mg, and K from canopies is a major pathway of these cations into forest soils. Our aim was to quantify rates of canopy leaching and to identify driving factors at the regional scale using annual fluxes of bulk precipitation and throughfall from 37 coniferous and deciduous forests of North and Central Europe. Total deposition of Ca, Mg, K, and H+ was estimated with Na as an index cation. The median canopy leaching increased in the order: Mg (0.11 kmolc ha–1 a–1) < Ca (0.31 kmolc ha–1 a–1) < K (0.39 kmolc ha–1 a–1). Canopy leaching of Ca and K was positively correlated with the calculated total H+ deposition and H+ buffered in the canopy, whereas canopy leaching of Mg was not. With contrasting effects, fluxes of SO4‐S and NH4‐N in throughfall explained to 64 % (P<0.001) of the Ca canopy leaching. Fluxes of NH4‐N and Ca were negatively correlated, suggesting that buffering of H+ by NH3 deposition reduced canopy leaching of Ca. Amount of bulk precipitation and SO4‐S in throughfall were identified as much weaker driving factors for canopy leaching of K (r2=0.28, P<0.01). Our results show that Ca is the dominant cation in buffering the H+ input in the canopy. At the regional and annual scale, canopy leaching of Mg appears to be unaffected by H+ deposition and H+ buffering in the canopy.
A Generalized Least Square Model for the Determination of Monomer Reactivity Ratios in Free Radical Copolymerization Systems
Authors: Habibi Ali , Vasheghani‐Farahani Ebrahim , Semsarzadeh Mohamad A. , Sadaghiani Kambiz
Published: April 2003

The reliable estimation of monomer reactivity ratios is a key problem in the development of process models, and, thus, is an important issue in both process design and control. Copolymers of isobutyl methacrylate (i‐BMA), and lauryl methacrylate (LMA) were prepared by free radical bulk copolymerization at 70 °C using 2,2′–azobisisobutyronitrile (AIBN) as initiator. The monomer reactivity ratios as well as the 95% confidence intervals were calculated from Fineman‐Ross, Ezrielev‐Brokhina‐Roskin, Kelen & Tudos, extended Kelen & Tudos and a linear iterative method proposed by Mao and Huglin. The estimation process was performed by applying nonlinear techniques based on Marquardt optimization, “ordinary least square” (OLS) and “generalized least square” (GLS) approaches and the results were compared with each other. The novel GLS estimator program developed during this study was employed to ascertain the shape of the copolymer composition curve and good agreement between experimental and calculated copolymer composition was obtained. Also, both real and simulated data was presented, which show GLS method is a statistically valid technique for estimating reactivity ratios by accounting response error structure. This new estimation method handles regression models with error terms that are heteroskedastic or serially correlated, or both.

95% joint confidence interval for reactivity ratios from “NLLS” analysis.

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95% joint confidence interval for reactivity ratios from “NLLS” analysis.
QSARs for the skin sensitization potential of aldehydes and related compounds
Authors: Patlewicz Grace , Roberts David W , Walker John D
Published: April 2003

Although not all aldehydes are skin sensitizers, many of them, covering a diverse range of structures, show varying degrees of sensitization potential. Based on consideration of their reaction chemistry, it is possible to identify structural features associated with sensitization potential or the lack of it. Many aldehydes, including several fragrance allergens, can sensitize by Schiff base formation. A QSAR based on reactivity and hydrophobicity parameters has been developed for these aldehydes. The QSAR can be extended to include 1,2‐diketones, which can also react by Schiff base formation. The findings indicate that for skin sensitization, as for several other areas of toxicology, chemicals are better classified in terms of their reaction chemistry rather than in terms of their functional groups, i.e., based on mechanisms of action as opposed to chemical class.
Mechanisms of action for general and polar narcosis: A difference in dimension
Authors: Roberts David W. , Costello Jayne F.
Published: April 2003

There are currently two schools of thought surrounding the existence of polar and non‐polar narcosis mechanisms in aquatic toxicity. Some authors argue that there is a real distinction between the two modes of action but recently support has grown for the suggestion that there may be no real difference and that the apparent distinction disappears when membrane/water partition ceofficients Kmware used, and has arisen purely because the octanol/water partition coefficient P is in fact an inadequate descriptor of partitioning into a lipid membrane. In this paper the evidence is analysed and it is concluded that although practically useful QSARs covering both general and polar narcotics can be developed based on log Kmw, there is nevertheless a real mechanistic difference between general and polar narcosis, which manifests itself by: significantly different QSARs, even when based on log Kmw, for general and polar narcotics treated separately; differences in FATS; non‐additivity between general narcotics and polar narcotics in mixture toxicity studies. We propose that this difference is based on a difference in physical chemistry, general narcotics acting via 3‐D partition (able to move in all directions in the hydrocarbon‐like interior of the membrane) and polar narcotics acting via 2‐D partition (involving binding between a functional group on the narcotic and the polar phosphatidyl choline head groups at the membrane surface). Based on this hypothesis a mathematical model is derived which can explain: why log P based QSARs covering diverse general narcotics are of statistically better quality than log P based QSARs covering diverse polar narcotics; why the slopes of log P based QSARs are larger for general narcosis than for polar narcosis: why the intercepts of log P based QSARs are larger for polar narcotics than for general narcotics; why some chemicals show additive toxicity both with general and polar narcotics.
QSAR analysis of metal ion toxicity data in sunflower callus cultures (Helianthus annuus “Sunspot”)
Authors: Enache Monica , Dearden John C. , Walker John D.
Published: April 2003

Toxicity data in sunflower callus cultures were determined for 12 metal ions: Ca(II), Cd(II), Co(II), Cu(II), K(I), Li(I), Mg(II), Mn(II), Na(I), Ni(II), Zn(II) and La(III). Based on fresh and dry weight measurements, in vitro EC50 values in solution and in callus tissue were determined. The correlations of the two toxicity data sets were modest. Pearson's correlation analysis of the toxicity data set determined in callus tissue and numerous parameters considered relevant in QSAR analysis showed the existence of a lower number of significant relationships, compared to the analogous analysis of EC50 values in solution. Presented here are the corresponding significant regression equations. Different types of properties appeared to correlate with toxicity, making it difficult to identify their potential significance, for example properties of the metallic state like densities, atomic properties like atomic radii and ionisation energies, chemical properties of metals like electronegativity and other surrogate measures considered to reflect qualities affecting interaction with ligands included as the chemical softness parameter, the covalent index, the first hydrolysis constant, quantitative measures of the stability of a metal complex in solution and hydration data.
Potential energy for slantwise parcel motion
Authors: Gray S. L. , Thorpe A. J.
Published: April 2003

Two formulations for the potential energy for slantwise motion are compared: one which applies strictly only to two‐dimensional flows (SCAPE) and a three‐dimensional formulation based on a Bernoulli equation. The two formulations share an identical contribution from the vertically integrated buoyancy anomaly and a contribution from different Coriolis terms. The latter arise from the neglect of (different) components of the total change in kinetic energy along a trajectory in the two formulations. This neglect is necessary in order to quantify the potential energy available for slantwise motion relative to a defined steady environment. Copyright © 2000 Royal Meteorological Society.