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Final States (final + states)
Selected AbstractsRelationship between the isotopically exchangeable and resin-extractable phosphate of deficient to heavily fertilized soilEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2000A. Schneider Summary The rate and extent of soil,solution transfer of orthophosphate ions (Pi) depend both on soil solution Pi concentration and on time. This is so both in experiments on sorption,desorption and in those on isotopic exchange. Because the two methods are based on different principles, it is questionable whether they give a similar quantification of Pi transfer. The amount of isotopically exchangeable Pi, E, was determined over periods of 100 minutes and described as a function of both time and Pi concentration in solution for three soil samples taken from field plots having different P fertilizer histories over 26 years of annual application. In separate experiments, amounts of Pi, Qd, were extracted from soil suspensions using three levels of anion exchange resin strips for periods ranging from 10 minutes to 7 days. Both initial and final solution Pi concentrations were measured. These concentrations and periods of resin-contact were used to predict the difference in E, ,E, between the initial and final states of the suspension,resin system using extrapolations of the equations fitted to the exchange data. Under conditions in which the solution concentration of Pi decreased during extraction the ,E values and the resin-extracted Pi values, Qd, were equal. It is thus possible, using the description of E, to predict the amount of Pi released from soil suspension knowing the initial and final solution Pi concentrations and the time it took for the system to pass from the initial to the final state. For the soil studied, identical amounts of mobile Pi, i.e. the Pi which participates in the soil,solution dynamics, may therefore be assessed by either isotopic exchange or desorption. [source] Means-End Behavior in Young Infants: The Interplay of Action Perception and Action ProductionINFANCY, Issue 6 2009Moritz M. Daum In 2 experiments, the interplay of action perception and action production was investigated in 6-month-old infants. In Experiment 1, infants received 2 versions of a means-end task in counterbalanced order. In the action perception version, a preferential looking paradigm in which infants were shown an actor performing means-end behavior with an expected and an unexpected outcome was used. In the action production version, infants had to pull a cloth to receive a toy. In Experiment 2, infants' ability to perform the action production task with a cloth was compared to their ability to perform the action production task with a less flexible board. Finally, Experiment 3 was designed to control for alternative low-level explanations of the differences in the looking times toward the final states presented in Experiment 1 by only presenting the final states of the action perception task without showing the initial action sequence. Results obtained in Experiment 1 showed that in the action perception task, infants discriminated between the expected and the unexpected outcome. This perceptual ability was independent of their actual competence in executing means- end behavior in the action production task. Experiment 2 showed no difference in 6-month-olds' performance in the action production task depending on the properties of the support under the toy. Similarly, in Experiment 3, no differences in looking times between the 2 final states were found. The findings are discussed in light of theories on the development of action perception and action production. [source] Consolidation around stone columns.INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 7 2009Influence of column deformation Abstract A solution is presented for the radial consolidation around stone columns under constant surcharge load. The solution considers the influence of vertical and radial deformation of the column, either in elastic and elastoplastic regimes. The solution is in terms of the average excess pore pressure in the soil. It is based on previous solutions, initially developed for rigid column, or including only vertical deformation. For elastic column, the solution gives the variation of strains and stresses between the undrained and final states, for which it coincides with the existing elastic solutions. All the results are given in closed form, and both the elastic and plastic deformations of the column lead to an equivalent coefficient of consolidation for the radial flow, which enables the application of the existing methods of integration of the consolidation equation. A parametric study is presented, showing the influence of the main problem features. A design example is used to illustrate the application to practical cases. Copyright © 2008 John Wiley & Sons, Ltd. [source] Vesicles as reactors of nanoparticles: an anomalous small-angle X-ray scattering study of the domains rich in copper ionsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2007Attila Bóta The formation of copper hydroxide and copper oxide particles in the gaps among the stacks of multilamellar vesicles is described, illustrating a new pathway in the preparation of nanometre-scale particles. The in situ structural characterization of both the solid particles and the vesicles as a reaction medium was performed in the initial and final states of the process by using anomalous small-angle X-ray scattering (ASAXS) and freeze-fracture methods. The ASAXS method provides a description of the particle-size distribution of the copper nanoparticles, in spite of the fact that they are present in low concentration. This method allows the particle formation and growth to be monitored throughout the whole time range of the synthesis. [source] Interpretation of the temperature dependence of equilibrium and rate constantsJOURNAL OF MOLECULAR RECOGNITION, Issue 5 2006Donald J. Winzor Abstract The objective of this review is to draw attention to potential pitfalls in attempts to glean mechanistic information from the magnitudes of standard enthalpies and entropies derived from the temperature dependence of equilibrium and rate constants for protein interactions. Problems arise because the minimalist model that suffices to describe the energy differences between initial and final states usually comprises a set of linked equilibria, each of which is characterized by its own energetics. For example, because the overall standard enthalpy is a composite of those individual values, a positive magnitude for ,Ho can still arise despite all reactions within the subset being characterized by negative enthalpy changes: designation of the reaction as being entropy driven is thus equivocal. An experimenter must always bear in mind the fact that any mechanistic interpretation of the magnitudes of thermodynamic parameters refers to the reaction model rather than the experimental system For the same reason there is little point in subjecting the temperature dependence of rate constants for protein interactions to transition-state analysis. If comparisons with reported values of standard enthalpy and entropy of activation are needed, they are readily calculated from the empirical Arrhenius parameters. Copyright © 2006 John Wiley & Sons, Ltd. [source] On the Scaling Behavior of the Force/Extension Relation of a ChainMACROMOLECULAR THEORY AND SIMULATIONS, Issue 7 2010Marios K. Kosmas Abstract Applying an extending force F along the end-to-end vector r of a chain enlarges the initial size ,i , |ri| leading to a final state with ,f larger than ,i. Assuming a power law dependence of the size , , N, of the chain on its length N, at the two different states with different exponents ,i and ,f, a scaling relationship is derived between the measure of the extending force F and the extension , of the chain. The exponent , of the force/extension relation, , , F,, depends on both exponents ,i and ,f of the initial and the final states. A relation between , and the exponents ,i and ,f is derived which permits the explanation of previous results and predicts some more. The scaling behavior is checked with the exactly soluble model of a random walk under a force. [source] Pressure dependence of the optical properties of wurtzite and rock-salt Zn1,xCoxO thin filmsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2007J. A. Sans Abstract In this paper we investigate the electronic structure of Zn1,xCoxO by means of optical absorption measurements under pressure. Thin films of Zn1,xCoxO with different Co content (from 1 to 30%) were prepared by pulsed laser deposition on mica substrates. Absorption spectra exhibit three main features that are clearly correlated to the Co content in the films: (i) absorption peaks in the infrared associated to crystal-field-split internal transitions in the Co 3d shell, with very small pressure coefficients due to their atomic character; (ii) a broad absorption band below the fundamental edge associated to charge transfer transitions, that exhibit relatively large pressure coefficients, indicating that the Co 3d final states must be strongly hybridized to the conduction band; and (iii) a blue-shifted fundamental absorption edge associated to band to band transitions with a pressure coefficient close to that of pure ZnO. In the up-stroke the transition pressure from wurtzite to rock-salt phase decrease almost linearly as the Co increases, from 9.5 GPa in pure ZnO to about 6.5 GPa for x = 30%. In the down-stroke pressure we observe a similar behavior, yielding a metastable rock-salt phase at room pressure, after a pressure cycle up to 15 GPa. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Magnetoabsorption coefficient of donor impurities in CdS quantum dotPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2006A. Didi Seddik Abstract A theoretical study of the donor-related absorption coefficient in spherical CdS quantum dots (QD) in the presence of a uniform magnetic field is performed. The wave functions and the eigenvalues of the initial and final states are obtained in the effective-mass approximation by using a variational method and a perturbation method, respectively. The results obtained show that the absorption coefficient presents essentially two peaks; one associated with on-center donors and another related to transitions involving donors at the QD edge. The dependences of the absorption coefficient on sample dimensions, the magnetic field strength and the light polarization are discussed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Polariton correlation in microcavities produced by parametric scatteringPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2005Wolfgang Langbein Abstract The spontaneous and self-stimulated parametric emission from a semiconductor microcavity after resonant pulsed excitation is measured. The emission of the lower polariton branch is resolved in two-dimensional momentum space, using either time-resolved or spectrally resolved detection. The polariton,polariton scattering dynamics is generally in good agreement with the theory using the nonlinearity due to the excitonic part and the dispersion due to the photonic part of the polariton. The peculiar figure-8 shaped distribution in momentum space of the final states of the parametric scattering is observed. Renormalization of the dispersion due to the bound biexciton state is found to influence the final state distribution. Using two pump directions the shape of the final state distribution can be changed to a peanut or oval for the mixed parametric processes. In this dual pump configuration, we find that polaritons in two distinct idler-modes interfere if and only if they share the same signal-mode, showing the existence of polariton pair correlations that store the "which-way" information. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Discontinuous deformation in an elastic material.POLYMER ENGINEERING & SCIENCE, Issue 10 2007Part 1. The concept of energy or work dissipation from a perfectly elastic material, due to a discontinuous deformation mechanism, is developed in this study. Dissipation occurs even from a perfectly elastic material, preferably an elastomer, when subjected to a discontinuous "jump" stretch or "jump" contraction. Stretching an elastomeric member through free extension requires a large amount of work. Such a sudden jump stretch of an elastic material is difficult to accomplish and is equivalent to thermodynamic free compression of a gas. The amount of work required can greatly exceed the strain energy stored in the material if the extension were applied without the jump or "shock" process. Interestingly, only part of the stored energy is recovered on unloading the elastomer the same way (through contraction). Excess work lost in contraction dissipates as heat but is not due to the common viscoelastic/plastic losses associated with internal friction in solids. Dissipation is possible even from a perfectly elastic material. Energy values associated in this jump deformation process are independent of the stress,strain curve path, and depend only on initial and final states for the material. Heat dissipation from an elastic rubber belt is examined and some applications extended from the developed principle are enunciated. POLYM. ENG. SCI., 47:1511,1520, 2007. © 2007 Society of Plastics Engineers [source] Competing Risks and Time-Dependent CovariatesBIOMETRICAL JOURNAL, Issue 1 2010Giuliana Cortese Abstract Time-dependent covariates are frequently encountered in regression analysis for event history data and competing risks. They are often essential predictors, which cannot be substituted by time-fixed covariates. This study briefly recalls the different types of time-dependent covariates, as classified by Kalbfleisch and Prentice [The Statistical Analysis of Failure Time Data, Wiley, New York, 2002] with the intent of clarifying their role and emphasizing the limitations in standard survival models and in the competing risks setting. If random (internal) time-dependent covariates are to be included in the modeling process, then it is still possible to estimate cause-specific hazards but prediction of the cumulative incidences and survival probabilities based on these is no longer feasible. This article aims at providing some possible strategies for dealing with these prediction problems. In a multi-state framework, a first approach uses internal covariates to define additional (intermediate) transient states in the competing risks model. Another approach is to apply the landmark analysis as described by van Houwelingen [Scandinavian Journal of Statistics 2007, 34, 70,85] in order to study cumulative incidences at different subintervals of the entire study period. The final strategy is to extend the competing risks model by considering all the possible combinations between internal covariate levels and cause-specific events as final states. In all of those proposals, it is possible to estimate the changes/differences of the cumulative risks associated with simple internal covariates. An illustrative example based on bone marrow transplant data is presented in order to compare the different methods. [source] | |||||||||||||