bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of buffer layers on the dislocation structure of heteroepitaxial systems
Authors: Bolkhovityanov Yu. B. , Vaulin Yu. D. , Gutakovsky A. K. , Stenin S. I. , Yudaev V. I. 
Published: July 2007

AbstractTransmission electron microscopy (TEM) as well as X‐ray topography (XRT) and X‐ray diffractometry have been used for investigation of the structure of the LPE heteroepitaxial system In0.05Ga0.95As‐InyGa1−yAs1−xPx‐GaAs(111) A. A critical value of the lattice misfit has been shown to exist at the metallurgical boundary ((Δa/a)* ≈ 10−3) which results in the change of the film nucleation and growth mechanism as well as the change of misfit dislocations (MDs) generation mechanism. With (Δa/a)0 > (Δa/a)* the nucleation and growth mechanism is mixed: island growth at the first stages of growth and layer‐by‐layer growth at large thicknesses. MDs are created in an “island film” developing a non‐ordered dislocation network. The density of threading dislocations (Nd) is ∼ 108 cm−2. With (Δa/a)0 < (Δa/a)* there is layer‐by‐layer mechanism of film's nucleation and growth from the very first stages of crystallization. MDs are injected into continuous layer along the inclined slip planes {111}, thus forming a regular three‐dimensional grid of MDs. Nd is less than 106 cm−2 in the case. A model of dislocation structure formation in heterolayers has been proposed. Within the frame of this model the two critical values of phosphorus concentration in the quaternary melt have been quantitatively determined. These are corresponding to the change of MD generation mechanism. The expected values of Nd for (Δa/a)0 > (Δa/a)* and (Δa/a)0 < (Δa/a)* have been theoretically determined.
The effect of solvents and crystallization conditions on crystal habit of cholesterol
Authors: Garti N. , Karpuj L. , Sarig S. 
Published: July 2007

AbstractThe effect of various organic solvents as well as the crystallization conditions on the crystal habit of anhydrous cholesterol have been studied. Both plates and needle‐like crystals can be obtained in a particular solvent depending on the degree of supersaturation of the solution. However, the crystals grown at about the same supersaturation, from different solvents, show differences in their habit indicating dependence on the solvent‐solute interaction. Thus, it is advisable not to identify needle‐like crystals with anhydrous‐cholesterol and plates with mono‐hydrate cholesterol without specifying the crystallization conditions. A prediction on the crystal habit length to width ratios can be made using those parameters.
The Analysis of Growth Kinetics in Liquid Phase Electroepitaxy (LPEE) of binary systems
Authors: Ivashchenko A. I. , Kopanskaya F. Ya. 
Published: July 2007

AbstractGrowth kinetics of binary systems in liquid phase electroepitaxy (LPEE) is analysed in terms of one‐dimensional forced diffusion with initial and boundary conditions reflecting the features of various modifications of LPEE. Electromigration of a solute in the melt and the Peltier effect at the interface between liquid and solid phases induced by electric current are taken into account.Three LPEE modifications are considered here. The first modification is when liquid phase is constantly riched due to dissolution of the semiconductor cathode. The second one‐when liquid phase is constantly riched from vapour phase by controlled vapour pressure. The third one‐when any source of the melt enrichment is absent.This consideration is limited by the assumption that the deviation of the solution heighs or convection doesn' affect the steady‐state temperature at the interfaces between solid and liquid phases. The obtained expressions for growth rate show that quantitative results of the epitaxial growth are closely connected with a concrete method of LPEE realization.
The precipitation of sparingly‐soluble metal salts from aqueous solution: Heterogeneous nucleus numbers at low to intermediate supersaturation
Authors: Packter A. , Alleem A. , Chauhan P. , Uppaladini S. C. 
Published: July 2007

AbstractThe precipitation of series of alkaline‐earth metal and transition hydroxides, sulphates, chromates and molybdates, hydrogen phosphate carbonates, oxalates and ‘oxinates’ were studied in aqueous solution of low to intermediate supersaturation. Heterogeneous nucleation probably occurred onto micro‐crystalline particles of some siliceous mineral (of the trigonal, hexagonal or cubic system), dispersed in the solution. The heterogeneous nucleus numbers for these precipitations then depended on the rates of the heterogeneous nucleation onto these substrates and the rates of the mononuclear growth of nuclei to crystallites (during the induction periods). Generally, Nhet values in polypropylene and glass beakers, at low supersaturation, varied from 104 to 1013 dm−3: the Nhet values then increased slightly with concentration and supersaturation according to the relation Nhet = KNβ, where KN is a function of the metal salt surface energy and an ‘epitaxy’ factor; β = 0.4–0.5. In turn, at any supersaturation, log Nhet = log N + Fσ, where N and F were constants for any precipitation: Nhet values then increased from 104 to 108 times for increase in σ from 50 to 150 mJ m−2.At any supersaturation and surface energy, Nhet values increased in the order monoclinic < orthohombic < tetragonal < trigonal crystals.
An evaluation of quarterly national institute forecasts
Authors: Holden K. , Peel D. A. 
Published: July 2007

AbstractThis paper examines the quarterly forecasts by the U.K. National Institute of Economic and Social Research of the rate of inflation and the change in real gross domestic product and its components for horizons of one to four quarters ahead in the U.K. The forecasts are tested to see if they satisfy three implications of the rational expectations hypothesis: unbiasedness, efficiency and consistency. Explicit consideration is given to the information set available when the forecasts are made. In general, the data are consistent with the rational expectations hypothesis and our results provide encouragement for the view that aggregate expectations will meet the ex post requirements of rationality.
An examination of the accuracy of judgemental confidence intervals in time series forecasting
Authors: O'Connor Marcus , Lawrence Michael 
Published: July 2007

AbstractThis paper examines the accuracy (calibration) of judgemental and selected statistical confidence intervals in time series forecasting. Using the forecasts and forecast errors produced by the deseasonalized single exponential smoothing method, three statistical intervals were produced utilizing three assumptions about the distribution of errors: the normal distribution, the empirical distribution and the distribution based on the Chebyshev inequality. Using 33 real‐life time series, results indicated that the judgemental confidence intervals were initially excessively overconfident, thus confirming the finding of Lichtenstein et al. (1982). However, calibration of the judgemental intervals improved considerably with feedback, and was found to be influenced by the degree of forecasting difficulty of the series.
The application of numerical models to assess dispersion and deposition in the event of a nuclear accident
Authors: Apsimon Helen M. , Wilson Julian 
Published: July 2007

AbstractNumerical models have been widely used in risk studies to estimate how hypothetical releases of radionuclides will disperse and lead to exposure of the population. In this context large numbers of possible scenarios are treated; absolute accuracy in simulating each particular situation is not necessary as long as the correct statistical distribution of consequences emerges. Since the Chernobyl accident there has been more interest in the use of numerical models as tools to assist in real‐time in emergency procedures if and when a nuclear accident occurs. However, the use of models in a real situation is distrusted by many people, who feel that the only way to assess an emergency situation is by making radiological measurements. This paper addresses uncertainties involved in modelling and argues that a combination of both approaches should be employed, using numerical modelling as an aid in intelligent interpretation of measurements, and suggesting priorities for international exchange of radiological data.
Uncertainty propagation and speculation in projective forecasts of environmental change: A lake‐eutrophication example
Authors: Van Straten Gerr T. , Keesman Karel J. 
Published: July 2007

AbstractThe issue of whether models developed for current conditions can yield correct predictions when used under changed control, as is often the case in environmental management, is discussed. Two models of different complexity are compared on the basis of performance criteria, but it appears that good performance at the calibration stage does not guarantee correctly predicted behavior. A requirement for the detection of such a failure of the model is that the prediction uncertainty range is known. Two techniques to calculate uncertainty propagation are presented and compared: a stochastic first‐order error propagation based on the extended Kalman filter (EKF), and a newly developed and robust Monte Carlo set‐membership procedure (MCSM). The procedures are applied to a case study of water quality, generating a projective forecast of the algal dynamics in a lake (Lake Veluwe) in response to management actions that force the system into a different mode of behavior. It is found that the forecast from the more complex model falls within the prediction uncertainty range, but its informative value is low due to large uncertainty bounds. As a substitute for time‐consuming revisions of the model, educated speculation about parameter shifts is offered as an alternative approach to account for expected but unmodelled changes in the system.
System identification and validation for output prediction of a dynamic hydrologic process
Authors: Jakeman A. J. , Thomas G. A. , Dietrich C. R. 
Published: July 2007

AbstractThe paper presents an identification procedure for a dynamic model of am hydrologic process. The process involves solute transport in streams subject to aquifer interaction and unsteady flows and the intended use of the model is prediction. Detailed assumptions and results are provided to illustrate the level of comprehensive analysis required to assess model adequacy. The assessment procedure easily generalizes to any dynamic model which is linear‐in‐the‐parameters. As a fundamental tool, instrumental variable algorithms can be adopted which have a number of attractive features. These algorithms make both model‐order identification and specification among alternatives a straightforward task. They are known to be consistent estimators in the presence of a wide class of errors. It is seen that they can be made stable and robust in the presence of data outliers. Instrumental variable algorithms can also be used which are asymptotically efficient and provide a covariance matrix of parameter estimates. The paper shows how they aid the quantification of predictive uncertainty and investigates the validity of the underlying assumptions. Further, it illustrates that, when instrumental variable algorithms are used in recursive mode, they can be used not only as an additional tool to access model inadequacy but also as an aid to model improvements.
Analysis and prediction of the population in Spain: 1910–2000
Authors: Garcia‐Ferrer Antonio , Hoyo Juan Del 
Published: July 2007

AbstractThe starting hypothesis of this paper was the actual occurrence of important interactions between demographic and socio‐economic factors when trying to reach population forecasts that may be more efficient than those obtained by mere extrapolative methods. In order to be able to implement this approach to the Spanish case it has been necessary to reconstruct first the Spanish population series by age and sex groups from 1910 to 1980. Later, we proceed to obtain population forecasts using alternative modeling strategies and comment on the potential problems that the new demographic situation may have for future public policy.
On the problem of forecasting prior to ‘price’ control and decontrol
Authors: Revankar Nagesh S. 
Published: July 2007

AbstractThe paper treats the forecasting problem in the context of a demand or supply equation, when the explanatory variable z1 = xi′z + et – the ‘price’ variable – is controlled (exogenous) in the forecast period – Case A; or vice versa – Case B. In either case, at least some parameters need to shift in value from the sample to the forecast period, and the forecasts in general need to use prior information on the forecast period values of such parameters. The paper assumes that shifts occur only πz, V(et), and the reduced‐form parameters involved in the exogeneity restriction. When V(et) is the only parameter to shift, neither case calls for any prior information. In other instances, Case A is less demanding than Case B in terms of prior information needs. Among other things, the paper draws attention to the relevance of the distinction between a conditional forecast and a controlled forecast in Case B.
Domestic and international macro‐economic effects of german economic and monetary union simulations on QUEST
Authors: Horn G. A. , Scheremet W. , Zwiener R. 
Published: July 2007

AbstractThis paper addresses the impact of German economic and monetary union on the world economy. The basic question is if positive growth effects of increased German imports dominate the negative forces caused by rising interest rates and varying exchange rates. From simulations on the multi‐country QUEST model which incorporates the major bilateral trade selections one can draw the conclusion that the former impact is stronger than the latter. Hence, in general, the world economy benefits from German unification.
Review of Deep Inelastic Charged Lepton Scattering
Authors: Nowak W.‐D. 
Published: July 2007

AbstractThe present situation in deep inelastic lepton‐nucleon scattering is reviewed from an experimenter's point of view. After describing, in some detail, the quark‐parton model (QPM) predictions the basic ideas of Quantum Chromodynamics (QCD) are illustrated. The perturbative QCD predictions for deep inelastic scattering are summarised discussing also their theoretical uncertainties of today. Past and present experiments on deep inelastic electron and muon scattering are compared regarding their ability to test these predictions. It is shown that all data is in very good agreement with the QPM and fully consistent with perturbative QCD. New results on lepton scattering off nuclei are discussed and confronted to recently invented phenomenological models.
On the Correlation Inequalities in Some Models Involving Fermions
Authors: Gielerak Roman 
Published: July 2007

AbstractUsing the Coleman (‐Fröhlich‐Seiler) theorem we have mapped chargeless sectors of some (generalized) Yukawa‐Thirring‐(Schwinger) two‐dimensional models onto pure Bose theories. Discussion of certain correlation inequalities in this framework is made. In particular, we proved that the first and second Griffiths‐Kelly‐Shermann correlation inequalities hold.Correlation inequalities suggest that there is on phase transition of the first order in scalar versions of these models. Some results on the D‐L‐R equations for these models are established, confirming previous suggestion.
Relativistic Two‐Fermion Problem with the Most General Electric and Magnetic Potentials
Authors: Yilmazer A. Ulvi 
Published: July 2007

AbstractThe energy equation of two spin‐1/2 particles interacting with their charges and anomalous magnetic moments is examined. Starting with the most general Hamiltonian already obtained by other authors, the relevant wave equation has been written in terms of the generators of the de Sitter group. The radial equations for four different two‐fermion systems are derived and the positronium case is studied in detail. Their bound state solutions are discussed and the similarity to the sixteen radial equations arrived at by other authors in completely different manner is pointed out.
Spontaneous Compactification of Extra Dimensions in Eleven‐Dimensional Quantum Gravity
Authors: van Hieu Nguyen 
Published: July 2007

AbstractThe reduction of the eleven‐dimensional pure gravity theory to a field theory to a field theory in the four‐dimensional Minkowski space‐time by means of the spontaneous compactification of the extra dimensions is investigated. The contribution of the quantum fluctuations of the eleven‐dimensional second rank symmetric tensor field to the curvatures of the space‐time and the compactified space of the extra dimensions are calculated in the one‐loop approximations. It is shown that there exist the values of the cosmological constant such that the resulting four‐dimensional theory is self‐consistent.
Renormalization of Quantum Field Theory in Curved Space‐Time and Renormalization Group Equations
Authors: Buchbinder I. L. 
Published: July 2007

AbstractThe structure of quantum field theory renormalization in curved space‐time is investigated. The equations allowing us to investigate the behaviour of vacuum energy and vertex functions in the limit of small distances in the external gravitational field are established. The behaviour of effective charges corresponding to the parameters of nonminimal coupling of the matter with the gravitational field is studied and the conditions under which asymptotically free theories become asymptotically conformally invariant are found. The examples of asymptotically conformally invariant theories are given. On the basis of a direct solution of renormalization group equations the effective potential in the external gravitational field and the effective action in the gravity with the high derivatives are obtained. The expression for the cosmological constant in terms of R2‐gravity Lagrangian parameters is given which does not contradict the observable data. Renormalization and renormalization group equations for the theory in curved space‐time with torsion are investigated.
Communication protocols with untraceability of sender and receiver
Authors: Mambo Masahiro , Kinoshita Hirotsugu , Tsujii Shigeo 
Published: July 2007

AbstractPrevious research on information security has focused on the protection of the contents of messages. But in many cases it is equally important to protect the identities of the sender and receiver and also the time of message transmission.This paper proposes communication protocols which make it impossible both for the entities other than the right receiver to decipher the message and for any third party to identify the communicating entities. Since it is impossible in these protocols for any third party to identify the communicators, the protocols are classified into four groups according to whether or not the communicating pair can identify each other. In addition, the security, the implementability, and the mutual relationship of these four kinds of communication protocols are studied.
Automatic extraction of eyeblink for psychological experiment
Authors: Tanabe Kiichi , Sugiyama Makoto 
Published: July 2007

AbstractEyeblink analysis using video tape recorders (VTR) is becoming prevalent in psychological research investigating the relationship between eyeblinks and the cognitive process. One issue faced in this methodology has been the automation of eyeblink detection. Therefore, in this paper, we propose a method for automatically extracting eyeblinks from dynamic images recorded by VTRs using image processing techniques. This method is based on the principle of monitoring temporal changes in color information on the surface of the eye that accompany blinking and extracting regions where the color information changes as the eyeblink regions. The feature of this method is to introduce color judgement tables to accelerate the processing speed of the color data comparison computations. Then, the extracted eyeblink regions are used to illustrate the effect of basic data that was extracted in relation to eyeblinks. A detection experiment was performed by first using the area of the eyeblink region (number of extracted pixels) extracted in each frame, determining whether a blink occurred in each frame, and specifying the eyeblink occurrence time. The result was 28 out of 30 eyeblinks were successfully detected. In addition, the blink waveforms measured to illustrate the individual characteristics of eyeblinks were detected for six subjects. We verified the representation of the progression of eyeblinks was, for the most part, favorable for the blink waveforms we obtained.
Impact of written information on women's use of postpartum services: a randomised controlled trial
Authors: KABAKIAN‐KHASHOLIAN TAMAR , CAMPBELL OONA M.R. 
Published: July 2007

AbstractBackground. This study evaluates the impact of providing women with written educational material on their satisfaction with care, and use of health services postpartum. Methods. All women having a live birth at 4 private hospitals in Lebanon were eligible. The sample consisted of 187 women in the intervention and 191 in the control arms. An intervention booklet was developed following a qualitative study of women's information needs; placebo material was 2 leaflets about childproofing the house. Field workers administered a baseline questionnaire to recruit all eligible women, and conducted follow‐up interviews 6–20 weeks postpartum at the women's residences. The written material was handed out to women just before discharge from hospital. At the baseline interview, interviewers and women were blinded to the nature of the written material. Outcome measures were a postpartum visit to a health professional after discharge and before the follow‐up interview, and satisfaction with maternity care received during pregnancy, delivery and postpartum. Results. Satisfaction with care during the postpartum period was 57.2% in the intervention and 38.9% in the control arm (p<0.001). Some 85% of women in the intervention arm had a postpartum visit compared to 55% in the control arm (p<0.001). Conclusion. In the context of high female literacy, the intervention is effective and requires few resources.
Quantitative magnetic resonance imaging of experimentally injured porcine intervertebral disc
Authors: Niinimäki J. , Ruohonen J. , Silfverhuth M. , Lappalainen A. , Kääpä E. , Tervonen O. 
Published: July 2007

Background: Changes in T2 relaxation time (T2-TR) and apparent diffusion coefficients (ADC) have been suggested to appear in the intervertebral disc before morphological changes. Such sensitive imaging methods could be beneficial in the targeting and follow-up of intradiscal gene therapy. Purpose: To investigate the sensitivity of quantitative magnetic resonance (MR) imaging methods (T2-TR and ADC) in early disc degeneration, using an experimental porcine intervertebral disc injury model, and to investigate their sensitivity in depicting biochemically controlled degenerative changes in the disc. Material and Methods: Six juvenile pigs underwent experimental annular stab incisions, one superficial and one reaching the nucleus pulposus. The animals underwent repeated 1.5T MR imaging and were sacrificed 4 or 8 weeks after operation. Presence of degenerative changes was controlled with biochemical analysis. Results: Discs with full-thickness annular incisions lost 30% of their sagittal mid-slice nucleus pulposus area in 2 weeks ( P<0.05). T2-TRs of the respective discs were on average 73% of the control discs ( P<0.05). Discs with full-thickness annular lesions showed increased ADC values 4 weeks and reduced ADC values 8 weeks after the operation, compared to control discs ( P<0.05). Biochemical analysis showed changes consistent with early degeneration. Conclusion: Early traumatic or degenerative changes are detectable with both T2-TR and ADC. The ADC in the early phase after experimental trauma seems to initially increase before decreasing.