TOWARD CONTROLLING NONPOINT SOURCE POLLUTION OF GROUNDWATER: A HIERARCHICAL POLICY FORMULATION GAME

An integrative approach to formulating agricultural policy instrument levels is suggested for controlling groundwater quality deterioration from agricultural chemical-use, while reconciling the conflicting goals of primary interest groups in the farm policy process. The paper develops a Stackelberg game-theoretic model of public policy formation that simultaneously determines endogenous price supports and nitrogen-use quota, as well as the optimal permissible water contamination. The analysis distinguishes between the private and social opportunity costs of producing agricultural crops and using groundwater as a repository for nitrate leachate from agricultural sources. It is recognized that the social benefit of using nitrogen in agriculture is less than the private benefit to producers. Private and social benefits, as well as optimal production and pollution solutions, will vary as the relative weights which policymakers attach to different social constituents change. The method developed in this paper may be applicable to any policy process in which policymakers exercise indirect influence over industrial production decisions through economic instruments.     

Domination dot-critical graphs

A graph G is dot-critical if contracting any edge decreases the domination number. It is totally dot-critical if identifying any two vertices decreases the domination number. We show that the totally dot-critical graphs essentially include the much-studied domination vertex-critical and edge-critical graphs as special cases. We investigate these properties, and provide a characterization of dot-critical and totally dot-critical graphs with domination number 2. We also consider the question of when a dot-critical graph contains a critical vertex.     

The dynamics of water exchange in gadolinium DOTA complexes studied by transition path sampling and potential of mean force methods

The mechanism of water exchange at the Gd centre of the two isomers of [Gd(iii)DOTA](-) (gadolinate(1-), [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetato(4-)-N1,N4,N7,N10,O1,O4,O7,O10]) has been explored using transition path sampling and potential of mean force methods to sample those regions of phase space inaccessible to standard molecular dynamics simulation. We find that there are definite differences in the details of the solvent rearrangement accompanying the exchange of the capping water molecule for the two isomers. We conclude that these solvent effects, rather than any differences in the binding energy of the capping water, are central in determining the exchange rate. We find that the potential of mean force studies yield absolute and relative rates of water exchange for the two isomers that are in good agreement with experiment.     

Effects of measurement techniques on the experimental characterization of crack tip opening angle-Δ<Emphasis Type="Italic">a</Emphasis> resistance curves

One of the most promising approaches to characterizing the stable tearing process for lower constraint configurations in metallic materials has been indicated to be the crack tip opening angle (CTOA) criterion. In this paper we examine the effect of measurement distance selection and the impact of measurement procedures/analysis on the experimental CTOA-Δa resistance curve behavior of a Ti-6Al-4V and an Al5083 alloy. A new, systematic procedure for carrying out the experimental, surface CTOA measurement process has been used, which has uncovered artifacts of measurement distance selection that have not been presented prior to this study. By studying the CTOA-Δa behavior using a rigidly defined and consistent method, it is apparent that the measurement distance behind the crack tip at which angles are measured has a direct impact on the shape of the early transitional behavior of the CTOA-Δa behavior as well as the critical, experimental CTOA values produced.     

Non-linear oscillator limit cycle analysis using a time transformation approach

A method is presented for the analysis of limit cycle behavior of autonomous non-linear oscillators characterized by second order ordinary differential equations containing a small parameter. The method differs from the classical perturbation methods in that the dependent variable is not expanded in a power series in the small parameter. Rather, a new independent variable is sought such that in its domain the motion is simple harmonic. Use of this time transformation technique to generate limit cycle phase portrait, amplitude and period is presented. We show results of the application of the method to the van der Pol oscillator, to an oscillator with quadratic damping, and to a modified van der Pol oscillator which is statically unstable in the limit of small motion.     

Fringe-pattern demodulation using an iterative linear digital phase locked loop algorithm

A novel technique called an iterative linear digital phase locked loop (DPLL) for fringe-pattern demodulation is presented. The proposed technique has better noise immunity than the basic one-dimensional DPLL algorithms (e.g., conventional and linear DPLLs) because it processes a fringe pattern in two dimensions. In the first iteration of the proposed algorithm, it uses a flat reference to estimate the phase of the fringe pattern. The estimated phase map resulting from the first iteration is smoothed using a moving average window and then it is used as a reference to estimate the phase of the fringe pattern in the second iteration. In the third iteration, the phase map resulting from the second iteration is smoothed and used as a reference to estimate the phase of the fringe pattern in the fourth iteration and so on until the demodulated phase map has a good signal-to-noise ratio.     

Das Atomgewicht des Magnesiums

Ohne Zusammenfassung     

Virtual stability: Constructing a simulation model

After a discussion of the importance of stability and instability for complex systems theory, we define the concept of virtual stability as a state in which a system employs self‐monitoring and adaptive control to maintain itself in a configuration that would otherwise be unstable. The energy expended in this gains the system an increase in its flexibility of behavioral response to environmental changes. A model designed to illustrate virtual stability is presented, followed by a brief discussion of the evolutionary advantage this capacity provides. This leads to the suggestion that such advantage gives an argument both for the directionality of evolution and for the emergence of self‐consciousness. © 2008 Wiley Periodicals, Inc. Complexity, 2009     

Eine Neubestimmung des Atomgewichtes des Zinks

Ohne Zusammenfassung